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Miyata, Toshio, Shunya Takizawa, and Charles van Ypersele de Strihou. "Hypoxia. 1. Intracellular sensors for oxygen and oxidative stress: novel therapeutic targets." American Journal of Physiology-Cell Physiology 300, no. 2 (2011): C226—C231. http://dx.doi.org/10.1152/ajpcell.00430.2010.
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A variety of human disorders, e.g., ischemic heart disease, stroke, kidney disease, eventually share the deleterious consequences of a common, hypoxic and oxidative stress pathway. In this review, we utilize recent information on the cellular defense mechanisms against hypoxia and oxidative stress with the hope to propose new therapeutic tools. The hypoxia-inducible factor (HIF) is a key player as it activates a broad range of genes protecting cells against hypoxia. Its level is determined by its degradation rate by intracellular oxygen sensors prolyl hydroxylases (PHDs). There are three different PHD isoforms (PHD1–3). Small molecule PHD inhibitors improve hypoxic injury in experimental animals but, unfortunately, may induce adverse effects associated with PHD2 inhibition, e.g., angiogenesis. As yet, no inhibitor specific for a distinct PHD isoform is currently available. Still, the specific disruption of the PHD1 gene is known to induce hypoxic tolerance, without angiogenesis and erythrocytosis, by reprogramming basal oxygen metabolism with an attendant decreased oxidative stress in hypoxic mitochondria. A specific PHD1 inhibitor might therefore offer a novel therapy against hypoxia. The nuclear factor-erythroid 2 p45-related factor 2 (Nrf2) regulates the basal and inducible expression of numerous antioxidant stress genes. Disruption of its gene exacerbates oxidative tissue injury. Nrf2 activity is modulated by Kelch-like ECH-associated protein 1 (Keap1), an intracellular sensor for oxidative stress. Inhibitors of Keap 1 may prove therapeutic against oxidative tissue injury.
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Li, Ningjun, Fan Yi, Christina M. Sundy, et al. "Expression and actions of HIF prolyl-4-hydroxylase in the rat kidneys." American Journal of Physiology-Renal Physiology 292, no. 1 (2007): F207—F216. http://dx.doi.org/10.1152/ajprenal.00457.2005.
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Hypoxia inducible factor (HIF) prolyl-4-hydroxylase domain-containing proteins (PHDs) promote the degradation of HIF-1α. Because HIF-1α is highly expressed in the renal medulla and HIF-1α-targeted genes such as nitric oxide synthase, cyclooxygenase, and heme oxygenase are important in the regulation of renal medullary function, we hypothesized that PHD regulates HIF-1α levels in the renal medulla and, thereby, participates in the control of renal Na+ excretion. Using real-time RT-PCR, Western blot, and immunohistochemical analyses, we have demonstrated that all three isoforms of PHD, PHD1, PHD2, and PHD3, are expressed in the kidneys and that PHD2 is the most abundant isoform. Regionally, all PHDs exhibited much higher levels in renal medulla than cortex. A furosemide-induced increase in renal medullary tissue Po2 significantly decreased PHD levels in renal medulla, whereas hypoxia significantly increased mRNA levels of PHDs in cultured renal medullary interstitial cells, indicating that O2 regulates PHDs. Functionally, the PHD inhibitor l-mimosine (l-Mim, 50 mg·kg−1·day−1 ip for 2 wk) substantially upregulated HIF-1α expression in the kidneys, especially in the renal medulla, and remarkably enhanced (by >80%) the natriuretic response to renal perfusion pressure in Sprague-Dawley rats. Inhibition of HIF transcriptional activity by renal medullary transfection of HIF-1α decoy oligodeoxynucleotides attenuated l-Mim-induced enhancement of pressure natriuresis, which confirmed that HIF-1α mediated the effect of l-Mim. These results indicate that highly expressed PHDs in the renal medulla make an important contribution to the control of renal Na+ excretion through regulation of HIF-1α and its targeted genes.
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Xing, Weirong, Sheila Pourteymoor, and Subburaman Mohan. "Ascorbic acid regulates osterix expression in osteoblasts by activation of prolyl hydroxylase and ubiquitination-mediated proteosomal degradation pathway." Physiological Genomics 43, no. 12 (2011): 749–57. http://dx.doi.org/10.1152/physiolgenomics.00229.2010.
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Mouse genetic studies reveal that ascorbic acid (AA) is essential for osteoblast (OB) differentiation and that osterix (Osx) was a key downstream target of AA action in OBs. To determine the molecular pathways for AA regulation of Osx expression, we evaluated if AA regulates Osx expression by regulating production and/or actions of local growth factors and extracellular matrix (ECM) proteins. Inhibition of actions of IGFs by inhibitory IGFBP-4, BMPs by noggin, and ECM-mediated integrin signaling by RGD did not block AA effects on Osx expression in OBs. Furthermore, blockade of components of MAPK signaling pathway had no effect on AA-induced Osx expression. Because AA is required for prolyl hydroxylase domain (PHD) activity and because PHD-induced prolyl-hydroxylation targets proteins to proteosomal degradation, we next tested if AA effect on Osx expression involves activation of PHD to hydroxylate and induce ubiquitin-proteosome-mediated degradation of transcriptional repressor(s) of Osx gene. Treatment of OBs with dimethyloxallyl glycine and ethyl 3, 4-dihydroxybenzoate, known inhibitors of PHD, completely blocked AA effect on Osx expression and OB differentiation. Knockdown of PHD2 expression by Lentivirus-mediated shRNA abolished AA-induced Osx induction and alkaline phosphatase activity. Furthermore, treatment of OBs with MG115, inhibitor of proteosomal degradation, completely blocked AA effects on Osx expression. Based on these data, we conclude that AA effect on Osx expression is mediated via a novel mechanism that involves PHD2 and proteosomal degradation of a yet to be identified transcriptional repressor that is independent of BMP, IGF-I, or integrin-mediated signaling in mouse OBs.
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Uchida, Lisa, Tetsuhiro Tanaka, Hisako Saito, et al. "Effects of a prolyl hydroxylase inhibitor on kidney and cardiovascular complications in a rat model of chronic kidney disease." American Journal of Physiology-Renal Physiology 318, no. 2 (2020): F388—F401. http://dx.doi.org/10.1152/ajprenal.00419.2019.
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Cardiovascular disease (CVD) is the main cause of death in patients with kidney disease. Hypoxia plays a crucial role in the progression of chronic kidney disease (CKD) and cardiovascular disease, which is associated with fibrosis, inflammation, and oxidative injury. Previous studies have indicated that prolyl hydroxylase (PHD) inhibitors, stabilizers of hypoxia-inducible factors (HIFs), can be used to treat acute organ injuries such as renal ischemia-reperfusion, myocardial infarction, and, in some contexts, CKD. However, the effects of PHD inhibitors on cardiovascular complications in CKD remain unknown. In the present study, we investigated whether HIF activation has a beneficial effect on kidney and cardiovascular outcomes in the remnant kidney model. We used the 5/6 nephrectomy model with the nitric oxide synthase inhibitor Nω-nitro-l-arginine (20 mg/L in the drinking water). Rats received diet with 0.005% enarodustat (PHD inhibitor) or vehicle for 8 wk starting 2 wk before 5/6 nephrectomy. Activation of HIF by the PHD inhibitor reduced cardiac hypertrophy and ameliorated myocardial fibrosis in association with restored capillary density and improvement in mitochondrial morphology. With regard to kidneys, enarodustat ameliorated fibrosis in association with reduced proinflammatory cytokine expression, reduced apoptosis, and restored capillary density, even though renal endpoints such as proteinuria and serum creatinine levels were not significantly affected by enarodustat, except for blood urea nitrogen levels at 4 wk. In addition, cardiac hypertrophy marker genes, including atrial natriuretic peptide, were suppressed in P19CL6 cells treated with enarodustat. These findings suggest that PHD inhibitors might show beneficial effects in cardiovascular complications caused by CKD.
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Schultz, Kelly, Vanishree Murthy, Jeffrey B. Tatro та Debbie Beasley. "Prolyl hydroxylase 2 deficiency limits proliferation of vascular smooth muscle cells by hypoxia-inducible factor-1α-dependent mechanisms". American Journal of Physiology-Lung Cellular and Molecular Physiology 296, № 6 (2009): L921—L927. http://dx.doi.org/10.1152/ajplung.90393.2008.
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Arterial O2 levels are thought to modulate vascular smooth muscle cell (VSMC) proliferation and vascular remodeling, but the mechanisms involved are poorly understood. Here, we tested the hypothesis that PHD2, a prolyl hydroxylase domain (PHD)-containing O2 sensor, modulates growth factor-induced proliferative responses of human pulmonary artery SMC (HPASMC). We found that both PHD1 and PHD2 were robustly expressed by HPASMC, and inhibiting prolyl hydroxylase activity pharmacologically by using the nonselective dioxygenase inhibitor dimethyloxalylglycine (DMOG) inhibited proliferation and cyclin A expression induced by PDGF-AB or FGF-2. Specific knockdown of PHD2 using small interfering RNAs had similar effects. The inhibitory effects of DMOG and PHD2 knockdown on proliferation and cyclin A expression were seen under both normoxic (20% O2) and moderately hypoxic (5% O2) conditions, and PHD2 expression was not affected by O2 level nor by stimulation with PDGF or FGF-2, indicating that the proproliferative influence of PHD2 does not involve alterations of its expression. Knockdown of PHD2 increased hypoxia-inducible factor (HIF)-1α expression, as expected, but we also found that HIF-1α knockdown abolished the inhibitory effect of PHD2 knockdown on PDGF-induced cyclin A expression. Therefore, we conclude that PHD2 promotes growth factor-induced responses of human VSMC, acting by HIF-1α-dependent mechanisms. Given the role of PHD2 as an oxygen sensor in mammalian cells, these results raise the possibility that PHD2 links VSMC proliferation to O2 availability.
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Frost, Julianty, Alessio Ciulli, and Sonia Rocha. "RNA-seq analysis of PHD and VHL inhibitors reveals differences and similarities to the hypoxia response." Wellcome Open Research 4 (January 29, 2019): 17. http://dx.doi.org/10.12688/wellcomeopenres.15044.1.
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Background:Hypoxia-inducible factor (HIF) transcription factors are well known to control the transcriptional response to hypoxia. Given the importance of cellular response to hypoxia, a number of pharmacological agents to interfere with this pathway have been developed and entered pre-clinical or clinical trial phases. However, how similar or divergent the transcriptional response elicited by different points of interference in cells is currently unknown.Methods:We performed RNA-sequencing to analyse the similarities and differences of transcriptional response in HeLa cells treated with hypoxia or chemical agents that stabilise HIF by inhibiting components of the hypoxia signalling pathway – prolyl hydroxylase (PHD) inhibitor or von Hippel–Lindau (VHL) inhibitor.Results:This analysis revealed that hypoxia produces the highest changes in gene transcription, with activation and repression of genes being in large numbers. Treatment with the PHD inhibitor IOX2 or the VHL inhibitor VH032 led mostly to gene activation, majorly via a HIF-dependent manner. These results were also confirmed by qRT-PCR using more specific and/or efficient inhibitors, FG-4592 (PHDs) and VH298 (VHL).Conclusion:PHD inhibition and VHL inhibition mimic gene activation promoted by hypoxia via a HIF-dependent manner. However, gene repression is mostly associated with the hypoxia response and not common to the response elicited by inhibitors of the pathway.
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Sugahara, Mai, Shinji Tanaka, Tetsuhiro Tanaka, et al. "Prolyl Hydroxylase Domain Inhibitor Protects against Metabolic Disorders and Associated Kidney Disease in Obese Type 2 Diabetic Mice." Journal of the American Society of Nephrology 31, no. 3 (2020): 560–77. http://dx.doi.org/10.1681/asn.2019060582.
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BackgroundProlyl hydroxylase domain (PHD) inhibitors, which stimulate erythropoietin production through the activation of hypoxia-inducible factor (HIF), are novel therapeutic agents used for treating renal anemia. Several PHD inhibitors, including enarodustat, are currently undergoing phase 2 or phase 3 clinical trials. Because HIF regulates a broad spectrum of genes, PHD inhibitors are expected to have other effects in addition to erythropoiesis, such as protection against metabolic disorders. However, whether such beneficial effects would extend to metabolic disorder–related kidney disease is largely unknown.MethodsWe administered enarodustat or vehicle without enarodustat in feed to diabetic black and tan brachyury (BTBR) ob/ob mice from 4 to 22 weeks of age. To elucidate molecular changes induced by enarodustat, we performed transcriptome analysis of isolated glomeruli and in vitro experiments using murine mesangial cells.ResultsCompared with BTBR ob/ob mice that received only vehicle, BTBR ob/ob mice treated with enarodustat displayed lower body weight, reduced blood glucose levels with improved insulin sensitivity, lower total cholesterol levels, higher adiponectin levels, and less adipose tissue, as well as a tendency for lower macrophage infiltration. Enarodustat-treated mice also exhibited reduced albuminuria and amelioration of glomerular epithelial and endothelial damage. Transcriptome analysis of isolated glomeruli revealed reduced expression of C-C motif chemokine ligand 2/monocyte chemoattractant protein-1 (CCL2/MCP-1) in enarodustat-treated mice compared with the vehicle-only group, accompanied by reduced glomerular macrophage infiltration. In vitro experiments demonstrated that both local HIF-1 activation and restoration of adiponectin by enarodustat contributed to CCL2/MCP-1 reduction in mesangial cells.ConclusionsThese results indicate that the PHD inhibitor enarodustat has potential renoprotective effects in addition to its potential to protect against metabolic disorders.
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Kosyna, Friederike K., Marie Nagel, Larissa Kluxen, Kim Kraushaar та Reinhard Depping. "The importin α/β-specific inhibitor Ivermectin affects HIF-dependent hypoxia response pathways". Biological Chemistry 396, № 12 (2015): 1357–67. http://dx.doi.org/10.1515/hsz-2015-0171.
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Abstract Hypoxia-inducible transcription factors (HIFs) regulate hundreds of genes involved in cellular adaptation to reduced oxygen availability. HIFs consist of an O2-labile α-subunit (primarily HIF-1α and HIF-2α) and a constitutive HIF-1β subunit. In normoxia the HIF-α subunit is hydroxylated by members of a family of prolyl-4-hydroxylase domain (PHD) proteins, PHD1-3, resulting in recognition by von Hippel-Lindau protein, ubiquitination and proteasomal degradation. In contrast, reduced oxygen availability inhibits PHD activity resulting in HIF-1α stabilisation and nuclear accumulation. Nuclear import of HIF-1α mainly depends on classical nuclear localisation signals (NLS) and involves importin α/β heterodimers. Recently, a specific inhibitor of nuclear import has been identified that inhibits importin α/β-dependent import with no effects on a range of other nuclear transport pathways involving members of the importin protein family. In this study we evaluated the physiological activity of this importin α/β-inhibitor (Ivermectin) in the hypoxia response pathway. Treatment with Ivermectin decreases binding activity of HIF-1α to the importin α/β-heterodimer. Moreover, HIF-1α nuclear localisation, nuclear HIF-1α protein levels, HIF-target gene expression, as well as HIF-transcriptional activity are reduced upon Ivermectin treatment. For the first time, we demonstrate the effect of specific importin α/β-inhibition on the hypoxic response on the molecular level.
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Chaturvedi, Anuhar, Michelle Maria Araujo Cruz, Ramya Goparaju, et al. "Prolyl Hydroxylase 3 (Phd3) Is a Therapeutic Target in Isocitrate Dehydrogenase 1 (IDH1) Mutated Acute Myeloid Leukemia." Blood 132, Supplement 1 (2018): 759. http://dx.doi.org/10.1182/blood-2018-99-110425.
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Abstract Background: About 40% of IDH1 mutated (IDH1mut) acute myeloid leukemia (AML) patients respond to IDH1 inhibitors with a median duration of response of 8.2 months. A better understanding of the biology of IDH1mut leukemia may further improve the treatment of these patients. IDH1mut produces R-2-hydroxyglutarate (R-2HG), which activates PHD1 and PHD2 but have negligible effects on PHD3. In the present study we assessed whether PHD3 plays a role in the pathogenesis of IDH1 mutated leukemia and can be targeted in a patient-derived xenograft (PDX) model of IDH1 mutated AML. Methods: Bone marrow cells from Phdwt and Phd3ko mice were immortalized with HoxA9, and IDH1wildtype (IDH1wt) and IDH1mut respectively, were constitutively expressed. The effects on cell proliferation, apoptosis and colony formation were evaluated in vitro, whereas the leukemic potential was evaluated in vivo by transplantation in syngeneic mice. To show that PHD3 is a therapeutic target, either IDH1mut cells from AML patients were transduced with shRNA against PHD3 and transplanted in immunocompromised mice, or leukemic cells from an AML patient with mutated IDH1 were xenografted in immunocompromised mice and treated with the PHD inhibitor molidustat. Results: In in-vitro functional assays loss of Phd3 specifically impaired proliferation, apoptosis and clonogenic capacity of HoxA9-IDH1mut but not HoxA9-IDH1wt cells. Likewise, in mouse transplantation assays, loss of Phd3 eliminated HoxA9-IDH1mut induced leukemia. However, Phd3 was dispensable to the engraftment and proliferation of HoxA9-IDH1wt cells. Additionally, the IDH1-independent model of MN1-induced leukemia remained unaltered in the absence of Phd3, indicating the specificity of the role of Phd3 in mutant IDH1-induced transformation. To identify molecular pathways that might explain in vitro and in vivo phenotypes gene expression profiling was performed. Immune and stress-response pathways as well as metabolism-related genes were most prominently dysregulated in Phd3ko IDH1-mutant cells. Analysis of dysregulated transcription factors by gene set enrichment analysis revealed a depletion of key oncogenic transcription factors (Myc, Rb, Stk33, and Rps14) in Phd3ko IDH1mut cells compared to Phd3ko IDH1wt cells. To study if IDH1mut signals to Phd3 through R-2HG, we transduced Phd3kocells, with a splice variant of mutant IDH1, which does not produce R-2HG but causes leukemia in mice with similar kinetics as in mice with the full-length IDH1 mutant protein. Interestingly, loss of Phd3 also eliminated leukemia in these mice, which demonstrates that mutant IDH1 signals through Phd3 independently of R-2HG. To study the functional relevance of PHD3 inhibition in patients, cells from an IDH1 mutated AML patient were transduced with an shRNA against PHD3 and were transplanted in immunodeficient NSG mice. Inhibition of PHD3 depleted human AML cells in the IDH1-mutated PDX model. Moreover, the PHD inhibitor molidustat was 50-fold more active in IDH1mut (80 nM) compared to IDH1wt AML patient cells (4000 nM) in colony-forming unit assays. In a xenograft model of IDH1 mutated AML, molidustat significantly prolonged survival compared to control-treated mice (P<.001). Conclusion: We demonstrate that the leukemogenic activity of the mutant IDH1 protein depends on PHD3 independently of R-2HG. We identified inhibition of PHD3 as a novel therapeutic strategy in IDH1 mutated AML. Since PHD3 can be targeted pharmacologically, combinatorial treatment of PHD3 and IDH1 inhibitors is warranted to improve eradication of leukemic stem cells in IDH1 mutated AML. #AC and MMAC share first authorship Disclosures Ganser: Novartis: Membership on an entity's Board of Directors or advisory committees. Heuser:Karyopharm: Research Funding; Daiichi Sankyo: Research Funding; Sunesis: Research Funding; Tetralogic: Research Funding; Bayer Pharma AG: Consultancy, Research Funding; StemLine Therapeutics: Consultancy; Janssen: Consultancy; Pfizer: Consultancy, Honoraria, Research Funding; BergenBio: Research Funding; Astellas: Research Funding; Novartis: Consultancy, Honoraria, Research Funding.
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Nakano, Daisuke, Li Lei, and Akira Nishiyama. "Modulistat, a PHD inhibitor, ameliorated erythropoiesis in adenine-induced nephropathy mice." Proceedings for Annual Meeting of The Japanese Pharmacological Society 93 (2020): 2—O—059. http://dx.doi.org/10.1254/jpssuppl.93.0_2-o-059.
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Ozurumba, Ezinne, Omana Mathew, Katsuri Ranganna, Myung Choi та Adebayo Oyekan. "Regulation of hypoxia inducible factor/prolyl hydroxylase binding domain proteins 1 by PPARα and high salt diet". Journal of Basic and Clinical Physiology and Pharmacology 29, № 2 (2018): 165–73. http://dx.doi.org/10.1515/jbcpp-2017-0074.
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Abstract Background: Hypoxia inducible factor (HIF)/prolyl hydroxylase domain (PHD)-containing proteins are involved in renal adaptive response to high salt (HS). Peroxisome proliferator activated receptor alpha (PPARα), a transcription factor involved in fatty acid oxidation is implicated in the regulation of renal function. As both HIF-1α/PHD and PPARα contribute to the adaptive changes to altered oxygen tension, this study tested the hypothesis that PHD-induced renal adaptive response to HS is PPARα-dependent. Methods: PPARα wild type (WT) and knock out (KO) mice were fed a low salt (LS) (0.03% NaCl) or a HS (8% NaCl) diet for 8 days and treated with hydralazine. PPARα and heme oxygenase (HO)-1 expression were evaluated in the kidney cortex and medulla. A 24-h urinary volume (UV), sodium excretion (UNaV), and nitrite excretion (UNOx V) were also determined. Results: PHD1 expression was greater in the medulla as compared to the cortex of PPARα WT mice (p<0.05) fed with a LS (0.03% NaCl) diet. The HS diet (8% NaCl) downregulated PHD1 expression in the medulla (p<0.05) but not the cortex of WT mice whereas expression was downregulated in the cortex (p<0.05) and medulla (p<0.05) of KO mice. These changes were accompanied by HS-induced diuresis (p<0.05) and natriuresis (p<0.05) that were greater in WT mice (p<0.05). Similarly, UNOx V, index of renal nitric oxide synthase (NOS) activity or availability and heme oxygenase (HO)-1 expression was greater in WT (p<0.05) but unchanged in KO mice on HS diet. Hydralazine, a PHD inhibitor, did not affect diuresis or natriuresis in LS diet-fed WT or KO mice but both were increased (p<0.05) in HS diet-fed WT mice. Hydralazine also increased UNOx V (p<0.05) with no change in diuresis, natriuresis, or HO-1 expression in KO mice on HS diet. Conclusions: These data suggest that HS-induced PPARα-mediated downregulation of PHD1 is a novel pathway for PHD/HIF-1α transcriptional regulation for adaptive responses to promote renal function via downstream signaling involving NOS and HO.
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Panne, Daniel. "Chromatin recognition and regulation of the acetyltransferase CBP/p300." Acta Crystallographica Section A Foundations and Advances 70, a1 (2014): C1586. http://dx.doi.org/10.1107/s2053273314084137.
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Gene regulation in higher eukaryotes requires recruitment of the transcriptional co-activators CBP/p300 that associate with transcriptional regulators and integrate a large number of signal transduction pathways. Recruitment of CBP/p300 results in acetylation and remodeling of inhibitory chromatin. Recently we have determined the 2.8Å crystal structure of the catalytic core of p300 containing its Bromodomain, the CH2 region and HAT domain in complex with the bi-substrate inhibitor, Lys-CoA. Unexpectedly the structure reveals that the CH2 region contains a discontinuous PHD domain which is interrupted by a RING domain. The Bromodomain, PHD, RING and HAT domains adopt an assembled configuration in which the RING domain is positioned over the HAT substrate binding pocket. Disease mutations that disrupt RING attachment lead to upregulation of HAT activity, revealing an auto-inhibitory role for this domain. Detailed investigation of chromatin substrate recognition showed that the Bromodomain preferentially interacts with histones containing combinations of acetylations rather than singly modified sequences, whereas the p300 PHD domain did not interact with canonical substrates. Our results demonstrate that the Bromodomain substrate specificity is compatible with HAT substrate acetylation patterns suggesting that positive feedback is likely an important component in establishment of active chromatin states. We here present progress in our understanding of the regulation of p300 activity, chromatin modification, readout and how disease-related mutations result in dysregulation of these activities.
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Matsunaga, Shinji, and Shuhei Tomita. "The effect of PHD inhibitor on tumor microenvironment and tumor immune response." Proceedings for Annual Meeting of The Japanese Pharmacological Society 92 (2019): 2—S13–2. http://dx.doi.org/10.1254/jpssuppl.92.0_2-s13-2.
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Matsunaga, Shinji, and Shuhei Tomita. "The effect of PHD inhibitor on tumor microenvironment and tumor immune response." Folia Pharmacologica Japonica 155, no. 1 (2020): 35–39. http://dx.doi.org/10.1254/fpj.19119.
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TAKEMURA, K., H. Nishi, T. Higashihara, and M. Nangaku. "SUN-285 PHD inhibitor and hypoxia influence on skeletal muscle glucose metabolism." Kidney International Reports 4, no. 7 (2019): S278. http://dx.doi.org/10.1016/j.ekir.2019.05.790.
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Nazir, Yasir, Hummera Rafique, Naghmana Kausar, et al. "Methoxy-Substituted Tyramine Derivatives Synthesis, Computational Studies and Tyrosinase Inhibitory Kinetics." Molecules 26, no. 9 (2021): 2477. http://dx.doi.org/10.3390/molecules26092477.
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Targeting tyrosinase for melanogenesis disorders is an established strategy. Hydroxyl-substituted benzoic and cinnamic acid scaffolds were incorporated into new chemotypes that displayed in vitro inhibitory effects against mushroom and human tyrosinase for the purpose of identifying anti-melanogenic ingredients. The most active compound 2-((4-methoxyphenethyl)amino)-2-oxoethyl (E)-3-(2,4-dihydroxyphenyl) acrylate (Ph9), inhibited mushroom tyrosinase with an IC50 of 0.059 nM, while 2-((4-methoxyphenethyl)amino)-2-oxoethyl cinnamate (Ph6) had an IC50 of 2.1 nM compared to the positive control, kojic acid IC50 16700 nM. Results of human tyrosinase inhibitory activity in A375 human melanoma cells showed that compound (Ph9) and Ph6 exhibited 94.6% and 92.2% inhibitory activity respectively while the positive control kojic acid showed 72.9% inhibition. Enzyme kinetics reflected a mixed type of inhibition for inhibitor Ph9 (Ki 0.093 nM) and non-competitive inhibition for Ph6 (Ki 2.3 nM) revealed from Lineweaver–Burk plots. In silico docking studies with mushroom tyrosinase (PDB ID:2Y9X) predicted possible binding modes in the catalytic site for these active compounds. Ph9 displayed no PAINS (pan-assay interference compounds) alerts. Our results showed that compound Ph9 is a potential candidate for further development of tyrosinase inhibitors.
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Favier, Francois B., Florian A. Britto, Benjamin Ponçon, et al. "Endurance training prevents negative effects of the hypoxia mimetic dimethyloxalylglycine on cardiac and skeletal muscle function." Journal of Applied Physiology 120, no. 4 (2016): 455–63. http://dx.doi.org/10.1152/japplphysiol.00171.2015.
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Hypoxic preconditioning is a promising strategy to prevent hypoxia-induced damages to several tissues. This effect is related to prior stabilization of the hypoxia-inducible factor-1α via inhibition of the prolyl-hydroxylases (PHDs), which are responsible for its degradation under normoxia. Although PHD inhibition has been shown to increase endurance performance in rodents, potential side effects of such a therapy have not been explored. Here, we investigated the effects of 1 wk of dimethyloxalylglycine (DMOG) treatment (150 mg/kg) on exercise capacity, as well as on cardiac and skeletal muscle function in sedentary and endurance-trained rats. DMOG improved maximal aerobic velocity and endurance in both sedentary and trained rats. This effect was associated with an increase in red blood cells without significant alteration of skeletal muscle contractile properties. In sedentary rats, DMOG treatment resulted in enhanced left ventricle (LV) weight together with impairment in diastolic function, LV relaxation, and pulse pressure. Moreover, DMOG decreased maximal oxygen uptake (state 3) of isolated mitochondria from skeletal muscle. Importantly, endurance training reversed the negative effects of DMOG treatment on cardiac function and restored maximal mitochondrial oxygen uptake to the level of sedentary placebo-treated rats. In conclusion, we provide here evidence that the PHD inhibitor DMOG has detrimental influence on myocardial and mitochondrial function in healthy rats. However, one may suppose that the deleterious influence of PHD inhibition would be potentiated in patients with already poor physical condition. Therefore, the present results prompt us to take into consideration the potential side effects of PHD inhibitors when administrated to patients.
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Melekhova, Anna, Mirjam Leeder, Thanakorn Pungsrinont, et al. "A Novel Splice Variant of the Inhibitor of Growth 3 Lacks the Plant Homeodomain and Regulates Epithelial–Mesenchymal Transition in Prostate Cancer Cells." Biomolecules 11, no. 8 (2021): 1152. http://dx.doi.org/10.3390/biom11081152.
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Inhibitor of growth 3 (ING3) is one of five members of the ING tumour suppressor family, characterized by a highly conserved plant homeodomain (PHD) as a reader of the histone mark H3K4me3. ING3 was reported to act as a tumour suppressor in many different cancer types to regulate apoptosis. On the other hand, ING3 levels positively correlate with poor survival prognosis of prostate cancer (PCa) patients. In PCa cells, ING3 acts rather as an androgen receptor (AR) co-activator and harbours oncogenic properties in PCa. Here, we show the identification of a novel ING3 splice variant in both the human PCa cell line LNCaP and in human PCa patient specimen. The novel ING3 splice variant lacks exon 11, ING3∆ex11, which results in deletion of the PHD, providing a unique opportunity to analyse functionally the PHD of ING3 by a natural splice variant. Functionally, overexpression of ING3Δex11 induced morphological changes of LNCaP-derived 3D spheroids with generation of lumen and pore-like structures within spheroids. Since these structures are an indicator of epithelial–mesenchymal transition (EMT), key regulatory factors and markers for EMT were analysed. The data suggest that in contrast to ING3, ING3Δex11 specifically modulates the expression of key EMT-regulating upstream transcription factors and induces the expression of EMT markers, indicating that the PHD of ING3 inhibits EMT. In line with this, ING3 knockdown also induced the expression of EMT markers, confirming the impact of ING3 on EMT regulation. Further, ING3 knockdown induced cellular senescence via a pathway leading to cell cycle arrest, indicating an oncogenic role for ING3 in PCa. Thus, the data suggest that the ING3Δex11 splice variant lacking functional PHD exhibits oncogenic characteristics through triggering EMT in PCa cells.
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Grzeszczak, Władysław, Dariusz Szczyra, and Mirosław Śnit. "Whether Prolyl Hydroxylase Blocker—Roxadustat—In the Treatment of Anemia in Patients with Chronic Kidney Disease Is the Future?" International Journal of Environmental Research and Public Health 18, no. 4 (2021): 1612. http://dx.doi.org/10.3390/ijerph18041612.
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In patients with chronic kidney disease (CKD), anemia develops gradually, which is primarily due to an inadequate synthesis of erythropoietin by the kidneys, as well as to iron disorders in the body, blood loss, shortened erythrocyte survival and inflammation. The currently accepted treatment employs iron, vitamin B12, folic acid supplementation and the use of erythropoiesis stimulants, which are administered only parenterally. Research is currently underway on the new erythropoiesis drugs that can be orally administered, i.e., hypoxia-inducible factor-propyl hydroxylase inhibitor (HIF-PHI) inhibitors which temporarily block propyl hydroxylase [PHD] catalysis and promote a transient increase in the expression of genes regulated by HIF, including kidney and liver erythropoietin [EPO]. Roxadustat is the first oral drug in this class and a potent HIF-PHD inhibitor, exerted to treat anemia in patients with CKD. In phase 1, 2 and 3 studies with CKD-affected patients, roxadustat was more effective to stimulate erythropoiesis for anemia correction than previously used drugs. Roxadustat can be orally given, unlike other erythropoiesis drugs with parenteral administration only, which grants roxadustat a considerable advantage. Our paper presents the results of studies with roxadustat applied for the treatment of anemia in CKD patients with or without dialysis. We are currently not yet able to know the exact role of roxadustat in the treatment of anemia in patients with CKD, but time will tell. It is possible that roxadustat has benefits an iron metabolism and cardiovascular risk.
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Yang, Ying, Yujun Dai, Xuejiao Yang, Songfang Wu, and Yueying Wang. "DNMT3A Mutation-Induced CDK1 Overexpression Promotes Leukemogenesis by Modulating the Interaction between EZH2 and DNMT3A." Biomolecules 11, no. 6 (2021): 781. http://dx.doi.org/10.3390/biom11060781.
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DNMT3A mutations are frequently identified in acute myeloid leukemia (AML) and indicate poor prognosis. Previously, we found that the hotspot mutation DNMT3A R882H could upregulate CDK1 and induce AML in conditional knock-in mice. However, the mechanism by which CDK1 is involved in leukemogenesis of DNMT3A mutation-related AML, and whether CDK1 could be a therapeutic target, remains unclear. In this study, using fluorescence resonance energy transfer and immunoprecipitation analysis, we discovered that increased CDK1 could compete with EZH2 to bind to the PHD-like motif of DNMT3A, which may disturb the protein interaction between EZH2 and DNMT3A. Knockdown of CDK1 in OCI-AML3 cells with DNMT3A mutation markedly inhibited proliferation and induced apoptosis. CDK1 selective inhibitor CGP74514A (CGP) and the pan-CDK inhibitor flavopiridol (FLA) arrested OCI-AML3 cells in the G2/M phase, and induced cell apoptosis. CGP significantly increased CD163-positive cells. Moreover, the combined application of CDK1 inhibitor and traditional chemotherapy drugs synergistically inhibited proliferation and induced apoptosis of OCI-AML3 cells. In conclusion, this study highlights CDK1 overexpression as a pathogenic factor and a potential therapeutic target for DNMT3A mutation-related AML.
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Jennings, I. G., R. G. M. Russell, W. L. F. Armarego, and R. G. H. Cotton. "Functional analysis of the effect of monoclonal antibodies on monkey liver phenylalanine hydroxylase." Biochemical Journal 235, no. 1 (1986): 133–38. http://dx.doi.org/10.1042/bj2350133.
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An analysis of the effect of eleven monoclonal antibodies on the functional characteristics of monkey liver phenylalanine hydroxylase is presented. These eleven antibodies have been found to react with eight distinct regions on the phenylalanine hydroxylase protein. PH1 antibody inhibits enzyme activity, is dependent on phenylalanine for its binding, and appears to be related to structural changes occurring during phenylalanine activation of the enzyme activity. PH2 and PH3 antibodies stimulate enzyme activity, their binding is inhibited by lysolecithin and this group apparently is recognizing structures involved in lysolecithin activation of the enzyme activity. PH5, PH10, PH12 and PH6 recognise sites on phenylalanine hydroxylase affected by lysolecithin activation.
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Marverti, Gaetano, Gaia Gozzi, Eleonora Maretti, et al. "A Peptidic Thymidylate-Synthase Inhibitor Loaded on Pegylated Liposomes Enhances the Antitumour Effect of Chemotherapy Drugs in Human Ovarian Cancer Cells." International Journal of Molecular Sciences 21, no. 12 (2020): 4452. http://dx.doi.org/10.3390/ijms21124452.
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There is currently no effective long-term treatment for ovarian cancer (OC) resistant to poly-chemotherapy regimens based on platinum drugs. Preclinical and clinical studies have demonstrated a strong association between development of Pt-drug resistance and increased thymidylate synthase (hTS) expression, and the consequent cross-resistance to the hTS inhibitors 5-fluorouracil (5-FU) and raltitrexed (RTX). In the present work, we propose a new tool to combat drug resistance. We propose to treat OC cell lines, both Pt-sensitive and -resistant, with dual combinations of one of the four chemotherapeutic agents that are widely used in the clinic, and the new peptide, hTS inhibitor, [D-Gln4]LR. This binds hTS allosterically and, unlike classical inhibitors that bind at the catalytic pocket, causes cell growth inhibition without inducing hTS overexpression. The dual drug combinations showed schedule-dependent synergistic antiproliferative and apoptotic effects. We observed that the simultaneous treatment or 24h pre-treatment of OC cells with the peptide followed by either agent produced synergistic effects even in resistant cells. Similar synergistic or antagonistic effects were obtained by delivering the peptide into OC cells either by means of a commercial delivery system (SAINT-PhD) or by pH sensitive PEGylated liposomes. Relative to non-PEGylated liposomes, the latter had been previously characterized and found to allow macrophage escape, thus increasing their chance to reach the tumour tissue. The transition from the SAINT-PhD delivery system to the engineered liposomes represents an advancement towards a more drug-like delivery system and a further step towards the use of peptides for in vivo studies. Overall, the results suggest that the association of standard drugs, such as cDDP and/or 5-FU and/or RTX, with the novel peptidic TS inhibitor encapsulated into PEGylated pH-sensitive liposomes can represent a promising strategy for fighting resistance to cDDP and anti-hTS drugs.
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Gough, Sheryl M., Fan Lee, Robert L. Walker, et al. "Leukemia Driven By a NUP98-Phd Domain Fusion Is Highly Sensitive To Disruption Of H3K4me3-Phd Domain Binding By a Small Molecule Inhibitor." Blood 122, no. 21 (2013): 3759. http://dx.doi.org/10.1182/blood.v122.21.3759.3759.
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Abstract NUP98 gene fusions, created by non-random chromosomal translocations, are associated with a wide spectrum of high risk hematologic malignancies, and typically lead to overexpression of abdominal-b HOXA genes, a common theme shared by ∼50% of AML patients. We have generated a transgenic mouse model of the NUP98-PHF23 (NP23) gene fusion, initially identified in patients with AML, which develop AML, erythroleukemia, pre-T lymphoblastic leukemia (pre-T LBL), and a novel pre-B1 B cell acute lymphoblastic leukemia (pre-B1 ALL). A common theme in the leukemias and the premalignant hematopoietic tissues, is the overexpression of a Hoxa/b +Meis1 stem cell-like gene expression signature. GSEA analysis reveals this signature to be enriched in both human AML and ALL malignancies, and in human HSPC profiles. In addition, we found Bahcc1, a gene not previously associated with malignancy, to consistently segregate with the Hoxa/b+Meis1 signature in the NP23 leukemias and the premalignant tissues, independent of hematopoietic cell lineage. Furthermore, data-mining revealed BAHCC1 to be markedly overexpressed in AML patients with HOXA9/MEIS1 overexpression, and in a subset of MLL rearranged pre-B-ALL patients, suggesting BAHCC1 may be a previously unsuspected marker of leukemic transformation. NUP98-PHF23 belongs to a subset of fusion oncoproteins (including some MLL- and NUP98-fusions) that are potently tumorigenic and act by abrogating the normal reading, writing and erasure of histone methylation. Wild type PHF23 binds H3K4me3 residues via a PHD domain, therefore we used ChIP-seq to characterize global chromatin H3K4me3 and NP23 enrichment in NP23 leukemia derived cell lines. The vast majority (88%) of NP23 binding sites were enriched for H3K4me3 binding. Conversely, the NP23 protein co-localized at only 1.6% of all H3K4me3 enriched sites (including Hoxa, Hoxb and Meis1 loci) identifying these sites as direct targets of the NP23 fusion protein. Given that the NP23 fusion appears to function, at least in part, via binding to H3K4me3 sites at specific loci, we hypothesized that NP23 cells would be sensitive to disruption of the H3K4me4 binding by the NP23 PHD domain. Treatment of leukemic NP23 cells with Tetraethylthiuram disulfide (Disulfiram), a small molecule shown to inhibit PHD domain binding of H3K4me3 marks in vitro, rapidly and selectively killed NP23 myeloblasts but not control myeloblast cell lines (188G3, 189E6 and 32D) at 2 µM. Cell death was rapid, being 100% complete within 24 hours. Cell death was preceded by decreased levels of NP23 protein bound at target loci and decreased expression of these loci (e.g., Hoxa7/9/10, Hoxb5 and Meis1). We conclude that inhibitors of H3K4me3 PHD domain readers are promising therapeutic compounds that can kill leukemic cells driven by proteins that aberrantly read or write the histone code. The NP23 model provides a robust platform on which to identify and improve such compounds. Disclosures: Denu: Sirtris-GSK: Consultancy.
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Chaturvedi, Anuhar, Charu Gupta, Stefan Kaulfuss, et al. "Efficacy of Chemotherapy, Phd-Inhibitor Molidustat or BRD4 Inhibitor JQ1 in Combination with Targeted Inhibition of Mutated IDH1 in Human AML In Vivo." Blood 134, Supplement_1 (2019): 3933. http://dx.doi.org/10.1182/blood-2019-124016.
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Background: Approximately 40% of AML patients with IDH1 mutation respond to monotherapy with the IDH1 inhibitor ivosidenib with a median duration of response of 8.2 months, suggesting that IDH1 inhibitors should be rationally combined with other agents to improve efficacy. We have previously shown the synergistic activity of the mutant IDH1 (mIDH1) inhibitor BAY1436032 with azacitidine. We have also shown that the leukemogenic activity of the mIDH1 protein depends on PHD3 independent of R-2HG and its inhibition as a novel therapeutic strategy (Chaturvedi et al. 2018). Inhibition of Brd4 has been shown to induce rapid differentiation and death of IDH2 mutated AML mouse models (Chen et al., 2013). In the present study, we assessed the combination of either conventional chemotherapy, prolyl hydroxylase (PHD) inhibitor molidustat or bromodomain inhibitor JQ1 with BAY1436032 (BAY) in a preclinical patient-derived xenograft (PDX) model of mIDH1 AML. Methods and Results: Leukemic cells from an AML patient with mutated IDH1, NPM1, FLT3-TKD and NRAS were xenografted in immunocompromised mice. We investigated the effects of BAY in sequential (seq) or simultaneous (sim) combination with cytarabine plus doxorubicin in our mIDH1 PDX model. The control groups were treated with either vehicle, BAY (150 mg/kg once daily p.o. continuously), or chemotherapy, which consisted of cytarabine (50 mg/kg once daily days 1-5 i.v.) and doxorubicin (1 mg/kg once daily days 1-3 i.v.). The treatment was repeated once after 29 days. The test groups were treated with BAY and chemotherapy in the doses mentioned above either starting both drugs on day 1 (sim group) or starting chemotherapy on day 1 and BAY on day 6 (seq group). Treatment with BAY was stopped after 12 weeks. Leukemic cells in peripheral blood constantly increased in vehicle and chemotherapy-treated mice with median time to 50% engraftment (MT 50%) of 84 and 112 days respectively. After stop of treatment, the percentage of leukemic cells increased in the group receiving BAY1436032 (MT 50%: 252 days) and sequential combination (MT 50%: 280 days), however, the MT50% was not reached with the simultaneous treatment (P<0.001). Median survival for vehicle-treated mice was 173 days, 206 days for chemotherapy-treated mice, 325 days for BAY treated mice, and 340 days for the sequential combination treatment. Strikingly, 5/8 mice treated simultaneously with BAY and chemotherapy survived until the end of the study at 400 days and the median survival was not reached. We hypothesized that combination therapy with BAY and molidustat may demonstrate superior anti-leukemic activity in comparison to single agents in the treatment of IDH1-mutant AML. mIDH1 PDX mice were treated with either vehicle, BAY at a dose of 150 mg/kg or molidustat at a dose of 10 mg/kg p.o. as monotherapy or in combination. The MT50% for Vehicle, Molidustat and BAY was 70, 70 and 182 days respectively,. However, the MT50% was significantly delayed (322 days) for the combination treatment (P<0.001). Interestingly, all mice treated with the combination had normal blood counts until week 40 and survived significantly longer than in the BAY group (median latency: 249 vs 179 days, P<0.001). Mutant IDH1 PDX mice were treated with either vehicle, BAY, BRD4 inhibitor JQ1 (50mg/kg i.p. once daily) or the combination of BAY and JQ1 for 12 weeks. JQ1 monotherapy showed a significant delay in leukemia engraftment compared to vehicle-treated mice in the first 12 weeks of treatment. During the treatment, the leukemic cells remained low in both BAY and combination treated mice but relapsed at the same time 4 weeks after the treatment had been stopped. Median survival for vehicle-treated mice was 139 days, 164 days for JQ1-treated mice, 220 days for BAY treated mice, and 242 days for the combination treatment (BAY vs combination; P=0.03). Conclusion: Similar to the combination treatment of BAY with azacitidine the concurrent administration of BAY with chemotherapy significantly improves efficacy of this combination compared to sequential administration. In addition, the combination of an IDH1 inhibitor with molidustat is a promising therapeutic approach, while the combination with the BRD4 inhibitor JQ1 did not improve the outcome compared to treatment with an IDH1 inhibitor alone. Our findings support ongoing and future clinical investigations and suggest that IDH1 inhibitors should be applied concurrently with chemotherapy. Disclosures Chaturvedi: Bayer Pharma AG, Berlin, Germany: Research Funding. Kaulfuss:Bayer Pharma AG, Berlin, Germany: Employment. Panknin:Bayer Pharma AG, Berlin, Germany: Employment. Wagner:Bayer Pharma AG, Berlin, Germany: Employment, Equity Ownership. Jeffers:Bayer Pharma AG, Whippany, NJ, USA: Employment. Haegebarth:Bayer Pharma AG, Berlin, Germany: Employment, Equity Ownership. Heuser:Synimmune: Research Funding; Bayer Pharma AG, Berlin: Research Funding.
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Nishide, Shunji, Shinji Matsunaga, Masayuki Shiota, et al. "Explore the effect of PHD inhibitor on innate immune systems in tumor mouse model." Proceedings for Annual Meeting of The Japanese Pharmacological Society 92 (2019): 2—YIA—28. http://dx.doi.org/10.1254/jpssuppl.92.0_2-yia-28.
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Philipp, Sebastian, Lin Cui, Barbara Ludolph, et al. "Desferoxamine and ethyl-3,4-dihydroxybenzoate protect myocardium by activating NOS and generating mitochondrial ROS." American Journal of Physiology-Heart and Circulatory Physiology 290, no. 1 (2006): H450—H457. http://dx.doi.org/10.1152/ajpheart.00472.2005.
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Protection from a prolyl hydroxylase domain-containing enzyme (PHD) inhibitor, desferoxamine (DFO), was recently reported to be dependent on production of reactive oxygen species (ROS). Ischemic preconditioning triggers the protected state by stimulating nitric oxide (NO) production to open mitochondrial ATP-sensitive K+ (mitoKATP) channels, generating ROS required for protection. We tested whether DFO and a second PHD inhibitor, ethyl-3,4-dihydroxybenzoate (EDHB), might have similar mechanisms. EDHB and DFO increased ROS generation by 50–75% ( P < 0.001) in isolated rabbit cardiomyocytes. This increase after EDHB exposure was blocked by Nω-nitro-l-arginine methyl ester (l-NAME), an NO synthase (NOS) inhibitor; ODQ, a guanylyl cyclase antagonist; and Rp-8-bromoguanosine-3′,5′-cyclic monophosphorothioate Rp isomer, a PKG blocker, thus implicating the NO pathway in EDHB's signaling. Glibenclamide, a nonselective KATP channel blocker, or 5-hydroxydecanoate, a selective mitoKATP channel antagonist, also prevented EDHB's ROS production, as did blockade of mitochondrial electron transport with myxothiazol. NOS is activated by Akt. However, neither wortmannin, an inhibitor of phosphatidylinositol-3-kinase, nor Akt inhibitor blocked EDHB-induced ROS generation, indicating that EDHB initiates signaling downstream of Akt. DFO also increased ROS production, and this effect was blocked by ODQ, 5-hydroxydecanoate, and N-(2-mercaptopropionyl)glycine, an ROS scavenger. DFO increased cardiomyocyte production of nitrite, a metabolite of NO, and this effect was blocked by an inhibitor of NOS. DFO also spared ischemic myocardium in intact hearts. This infarct-sparing effect was blocked by ODQ, l-NAME, and N-(2-mercaptopropionyl)glycine. Hence, DFO and EDHB stimulate NO-dependent activation of PKG to open mitoKATP channels and produce ROS, which act as second messengers to trigger entrance into the preconditioned state.
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Ehling, Manuel, Ward Celus, Rosa Martín-Pérez та ін. "B55α/PP2A Limits Endothelial Cell Apoptosis During Vascular Remodeling". Circulation Research 127, № 6 (2020): 707–23. http://dx.doi.org/10.1161/circresaha.119.316071.
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Rationale: How endothelial cells (ECs) migrate and form an immature vascular plexus has been extensively studied. Yet, mechanisms underlying vascular remodeling remain poorly established. A better understanding of these processes may lead to the design of novel therapeutic strategies complementary to current angiogenesis inhibitors. Objective: Starting from our previous observations that PP2A (protein phosphatase 2) regulates the HIF (hypoxia-inducible factor)/PHD-2 (prolyl hydroxylase 2)-constituted oxygen machinery, we hypothesized that this axis could play an important role during blood vessel formation, tissue perfusion, and oxygen restoration. Methods and Results: We show that the PP2A regulatory subunit B55α is at the crossroad between vessel pruning and vessel maturation. Blood vessels with high B55α counter cell stress conditions and thrive for stabilization and maturation. When B55α is inhibited, ECs cannot cope with cell stress and undergo apoptosis, leading to massive pruning of nascent blood vessels. Mechanistically, we found that the B55α/PP2A complex restrains PHD-2 activity, promoting EC survival in a HIF-dependent manner, and furthermore dephosphorylates p38, altogether protecting ECs against cell stress occurring, for example, during the onset of blood flow. In tumors, EC-specific B55α deficiency induces pruning of immature-like tumor blood vessels resulting in delayed tumor growth and metastasis, without affecting nonpathological vessels. Consistently, systemic administration of a pan-PP2A inhibitor disrupts vascular network formation and tumor progression in vivo without additional effects on B55α-deficient vessels. Conclusions: Our data underline a unique role of the B55α/PP2A phosphatase complex in vessel remodeling and suggest the use of PP2A-inhibitors as potent antiangiogenic drugs targeting specifically nascent blood vessels with a mode-of-action complementary to VEGF-R (vascular endothelial growth factor receptor)-targeted therapies. Graphical Abstract: A graphical abstract is available for this article.
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Hong, Yu Ah, So Young Jung, Keum Jin Yang та ін. "Cilastatin Preconditioning Attenuates Renal Ischemia-Reperfusion Injury via Hypoxia Inducible Factor-1α Activation". International Journal of Molecular Sciences 21, № 10 (2020): 3583. http://dx.doi.org/10.3390/ijms21103583.
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Cilastatin is a specific inhibitor of renal dehydrodipeptidase-1. We investigated whether cilastatin preconditioning attenuates renal ischemia-reperfusion (IR) injury via hypoxia inducible factor-1α (HIF-1α) activation. Human proximal tubular cell line (HK-2) was exposed to ischemia, and male C57BL/6 mice were subjected to bilateral kidney ischemia and reperfusion. The effects of cilastatin preconditioning were investigated both in vitro and in vivo. In HK-2 cells, cilastatin upregulated HIF-1α expression in a time- and dose-dependent manner. Cilastatin enhanced HIF-1α translation via the phosphorylation of Akt and mTOR was followed by the upregulation of erythropoietin (EPO) and vascular endothelial growth factor (VEGF). Cilastatin did not affect the expressions of PHD and VHL. However, HIF-1α ubiquitination was significantly decreased after cilastatin treatment. Cilastatin prevented the IR-induced cell death. These cilastatin effects were reversed by co-treatment of HIF-1α inhibitor or HIF-1α small interfering RNA. Similarly, HIF-1α expression and its upstream and downstream signaling were significantly enhanced in cilastatin-treated kidney. In mouse kidney with IR injury, cilastatin treatment decreased HIF-1α ubiquitination independent of PHD and VHL expression. Serum creatinine level and tubular necrosis, and apoptosis were reduced in cilastatin-treated kidney with IR injury, and co-treatment of cilastatin with an HIF-1α inhibitor reversed these effects. Thus, cilastatin preconditioning attenuated renal IR injury via HIF-1α activation.
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Nurmemmedov, Elmar, and Santosh Kesari. "DDRE-11. DEVELOPMENT OF THE FIRST-IN-CLASS INHIBITOR OF CHD4 - SENSITIZING RESISTANT GLIOMAS." Neuro-Oncology 22, Supplement_2 (2020): ii63. http://dx.doi.org/10.1093/neuonc/noaa215.256.
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Abstract Glioblastoma is a lethal brain tumor with high recurrence rate. CHD4 overexpression, which drives resistance to DNA damage, is one of the major sources of recurrence. Since standard GBM treatments like radiation and temozolomide chemotherapy create DNA damage, inhibition of CHD4 offers a new therapeutic option for resensitizing GBM. CHD4 is a ubiquitously expressed ATP-dependent chromatin remodeler, which plays a crucial role in epigenetic regulation of gene expression and in DNA damage repair. Structurally, CHD4 contains an HMG-like domain, PHD domains, two chromodomains, a catalytic ATPase module, two domains of unknown function (DUF) and a C-terminal domain CHDCT2. Currently, no specific inhibitors targeting this chromatin remodeler have been reported yet. We aim to develop the first-in-class inhibitor targeting chromo-domain of CHD4. We have performed in silico screens to identify small molecules binding to the chromo-domains of CHD4. We present our growing in vitro data demonstrating biophysical properties and mechanism-of-action of these novel inhibitors. We expect that the experiments proposed here will result in the development of the first-in-class CHD4 inhibitor which can be used in the future not only to better study the physiological role of CHD4 but also to determine its potential as a novel targeted therapy for GBM.
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Coakley, Eoin, Alaa Ahmad, Kajal Larson, et al. "LB6. EDP-938, a Novel RSV N-Inhibitor, Administered Once or Twice Daily Was Safe and Demonstrated Robust Antiviral and Clinical Efficacy in a Healthy Volunteer Challenge Study." Open Forum Infectious Diseases 6, Supplement_2 (2019): S995. http://dx.doi.org/10.1093/ofid/ofz415.2489.
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Abstract Background Respiratory syncytial virus (RSV) represents an important global health challenge with significant morbidity and mortality in infants, elderly, and immunocompromised adults. No effective therapy is currently available. EDP-938 demonstrates potent in vitro activity against RSV Subtypes A and B. We report data from EDP 938-101, a double-blind, placebo-controlled, Phase 2a study that evaluated EDP-938 in adult volunteers inoculated with RSV-A Memphis 37b. Methods Subjects were healthy volunteers, 18–45 years, who were sero-suitable (i.e., lower 25th percentile). After RSV inoculation on Study Day 0, subjects had 12 hourly nasal wash monitored for RSV infection by qualitative RSV RT–PCR. On Study Day 5 or previously if qualitative RT–PCR was RSV+, subjects were randomized to receive 5 days of EDP-938 600 mg once daily (QD arm) or 500 mg loading dose then 300 mg twice daily (BID arm), or placebo twice daily. Assessments included 12 hourly nasal wash for quantitative RSV viral load, 8 hourly RSV Total Symptom Scoring (TSS) and daily mucus weights. Safety assessments were continued though Day 28 (last follow-up). The primary endpoint was the RSV viral load area under the curve (AUC) from first dose through Day 12 among RSV-infected subjects, defined as the Intent To Treat-Infected (ITT-I) population. The study was fully powered for both RSV viral load and TSS endpoints. Results A total of 115 subjects were randomized and inoculated; 86 were included in the ITT-I analysis. The primary and secondary efficacy endpoints were achieved with high statistical significance in QD and BID arms (figure and table). Among EDP-938 recipients all adverse events (AEs) were mild except for a single AE of moderate dyspepsia in the BID arm and events of moderate headache (n = 2) and hypoacusis (n = 1) in the placebo arm. All AEs resolved in follow-up. Conclusions In the RSV Challenge study, EDP-938 administered once or twice daily achieved primary and key secondary endpoints with robust reductions in RSV viral load (by both qRT–PCR and plaque assays), symptom scores and mucus weights. These data support the further clinical evaluation of EDP-938 in populations at risk of severe RSV disease. Disclosures Eoin Coakley, MD, Enanta Pharmaceuticals (Employee), Alaa Ahmad, PhD, Enanta Pharmaceuticals (Employee), Kajal Larson, PhD, Enanta Pharmaceuticals (Employee), Ty McClure, PhD, Enanta Pharmaceuticals (Employee), Kai Lin, PhD, Enanta Pharmaceuticals (Employee), Kursten Tenhoor, n/a, Enanta Pharmaceuticals (Consultant), Kingsley Eze, n/a, hVIVO Services Ltd. (Employee), Nicolas Noulin, PhD, No financial relationships or conflicts of interest, Veronika Horvathova, MBChB, MSc, hVIVO Services Limited (Other Financial or Material Support, Employed by hVIVO during the conduct of the study), Bryan Murray, MBBS, No financial relationships or conflicts of interest, Mark Baillet, PhD, S-CUBED (Employee), Julie Mori, PhD, hVIVO (Employee, Shareholder) Nathalie Adda, MD, Enanta Pharmaceuticals (Employee).
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Sridharan, Vijayalakshmi, Jason Guichard, Rachel M. Bailey, Harinath Kasiganesan, Craig Beeson, and Gary L. Wright. "The prolyl hydroxylase oxygen-sensing pathway is cytoprotective and allows maintenance of mitochondrial membrane potential during metabolic inhibition." American Journal of Physiology-Cell Physiology 292, no. 2 (2007): C719—C728. http://dx.doi.org/10.1152/ajpcell.00100.2006.
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The cellular oxygen sensor is a family of oxygen-dependent proline hydroxylase domain (PHD)-containing enzymes, whose reduction of activity initiate a hypoxic signal cascade. In these studies, prolyl hydroxylase inhibitors (PHIs) were used to activate the PHD-signaling pathway in cardiomyocytes. PHI-pretreatment led to the accumulation of glycogen and an increased maintenance of ATP levels in glucose-free medium containing cyanide. The addition of the glycolytic inhibitor 2-deoxy-d-glucose (2-DG) caused a decline of ATP levels that was indistinguishable between control and PHI-treated myocytes. Despite the comparable levels of ATP depletion, PHI-preconditioned myocytes remained significantly protected. As expected, mitochondrial membrane potential (ΔΨmito) collapses in control myocytes during cyanide and 2-DG treatment and it fails to completely recover upon washout. In contrast, ΔΨmito is partially maintained during metabolic inhibition and recovers completely on washout in PHI-preconditioned cells. Inclusion of rotenone, but not oligomycin, with cyanide and 2-DG was found to collapse ΔΨmito in PHI-pretreated myocytes. Thus, continued complex I activity was implicated in the maintenance of ΔΨmito in PHI-treated myocytes, whereas a role for the “reverse mode” operation of the F1F0-ATP synthase was ruled out. Further examination of mitochondrial function revealed that PHI treatment downregulated basal oxygen consumption to only ∼15% that of controls. Oxygen consumption rates, although initially lower in PHI-preconditioned myocytes, recovered completely upon removal of metabolic poisons, while reaching only 22% of preinsult levels in control myocytes. We conclude that PHD oxygen-sensing mechanism directs multiple compensatory changes in the cardiomyocyte, which include a low-respiring mitochondrial phenotype that is remarkably protected against metabolic insult.
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Sridharan, Vijayalakshmi, Jason Guichard, Chuan-Yuan Li, Robin Muise-Helmericks, Craig Cano Beeson, and Gary L. Wright. "O2-sensing signal cascade: clamping of O2 respiration, reduced ATP utilization, and inducible fumarate respiration." American Journal of Physiology-Cell Physiology 295, no. 1 (2008): C29—C37. http://dx.doi.org/10.1152/ajpcell.00466.2007.
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These studies explore the consequences of activating the prolyl hydroxylase (PHD) O2-sensing pathway in spontaneously twitching neonatal cardiomyocytes. Full activation of the PHD pathway was achieved using the broad-spectrum PHD inhibitor (PHI) dimethyloxaloylglycine (DMOG). PHI treatment of cardiomyocytes caused an 85% decrease in O2 consumption and a 300% increase in lactic acid production under basal conditions. This indicates a ∼75% decrease in ATP turnover rate, inasmuch as the increased ATP generation by glycolysis is inadequate to compensate for the lower respiration. To determine the extent to which decreased ATP turnover underlies the suppressed O2 consumption, mitochondria were uncoupled with 2,4-dinitrophenol. We were surprised to find that 2,4-dinitrophenol failed to increase O2 consumption by PHI-treated cells, indicating that electron transport chain activity, rather than ATP turnover rate, limits respiration in PHI-treated cardiomyocytes. Silencing of hypoxia-inducible factor-1α (HIF-1α) expression restored the ability of uncoupled PHI-treated myocytes to increase O2 consumption; however, basal O2 uptake rates remained low because of the unabated suppression of cellular ATP consumption. Thus it appears that respiration is actively “clamped” through an HIF-dependent mechanism, whereas HIF-independent mechanisms are responsible for downregulation of ATP consumption. In addition, we find that PHD pathway activation enables mitochondria to utilize fumarate as a terminal electron acceptor when cytochrome c oxidase is inactive. The source of fumarate for this unusual respiration is derived from aspartate via the purine nucleotide cycle. In sum, these studies show that the O2-sensing pathway is sufficient to actively “clamp” O2 consumption and independently suppress cellular ATP consumption. The PHD pathway also enables the mitochondria to utilize fumarate for respiration.
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Lob, Sibylle, Krystyna Kazmierczak, Greg Stone, and Daniel F. Sahm. "1570. In Vitro Activity of Ceftazidime-Avibactam and Comparator Agents Against Enterobacterales from ICU and Non-ICU Wards Collected in Latin America and Globally as part of the ATLAS Surveillance Program 2017-2018." Open Forum Infectious Diseases 7, Supplement_1 (2020): S784. http://dx.doi.org/10.1093/ofid/ofaa439.1750.
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Abstract Background Ceftazidime-avibactam (CAZ-AVI) is a β-lactam/non-β-lactam β-lactamase inhibitor combination with activity against Enterobacterales producing class A, C and some class D β-lactamases. Resistance caused by these β-lactamases is especially high in ICUs. This study evaluated the in vitro activity of CAZ-AVI and comparators against Enterobacterales isolates from patients in ICU and non-ICU wards. Methods Non-duplicate clinical isolates were collected in 2017-2018 from patients in Asia/Pacific, Europe, Latin America, and Middle East/Africa. Susceptibility testing was performed using CLSI broth microdilution and interpreted using CLSI 2020 and FDA (tigecycline) breakpoints. PCR and sequencing were used to determine the β-lactamase genes present in all isolates with meropenem (MEM) MIC &gt;1 µg/ml, and Escherichia coli, Klebsiella spp. and Proteus mirabilis with aztreonam or ceftazidime MIC &gt;1 µg/ml. Results The activity of CAZ-AVI and comparators is shown in the table. Susceptibility rates among global Enterobacterales were generally lower for isolates from patients in ICU than non-ICU wards, but this difference was small for CAZ-AVI, which inhibited ≥97% of isolates from both ward types. Among MEM-nonsusceptible (NS) isolates, CAZ-AVI was active against 66.5% and 68.1% of ICU and non-ICU isolates, respectively (of which 31.8% and 30.8%, respectively, carried metallo-β-lactamases [MBLs]). CAZ-AVI inhibited &gt;97% of MEM-NS MBL-negative isolates collected globally. Antimicrobial activity against all Enterobacterales from both ICU and non-ICU wards in Latin America (LA) was generally similar to the global average. Among MEM-NS isolates, antimicrobial activity of CAZ-AVI and TGC was higher in LA than the global average among isolates from both ward types, at least partly because of a lower proportion of MBL-positive isolates in this subset (15.8% and 17.9% in ICU and non-ICUs, respectively). CAZ-AVI inhibited 100% of MEM-NS MBL-negative isolates from LA. Table Conclusion CAZ-AVI provides a valuable treatment option for infections caused by Enterobacterales that do not carry MBLs, including those among patients in ICU wards, where antimicrobial resistance is typically higher. Disclosures Sibylle Lob, PhD, IHMA (Employee)Pfizer, Inc. (Consultant) Krystyna Kazmierczak, PhD, IHMA (Employee)Pfizer, Inc. (Consultant) Greg Stone, PhD, AztraZeneca (Shareholder, Former Employee)Pfizer, Inc. (Employee) Daniel F. Sahm, PhD, IHMA (Employee)Pfizer, Inc. (Consultant)Shionogi & Co., Ltd. (Independent Contractor)
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Martin, David G. E., Kristin Baetz, Xiaobing Shi, et al. "The Yng1p Plant Homeodomain Finger Is a Methyl-Histone Binding Module That Recognizes Lysine 4-Methylated Histone H3." Molecular and Cellular Biology 26, no. 21 (2006): 7871–79. http://dx.doi.org/10.1128/mcb.00573-06.
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ABSTRACT The ING (inhibitor of growth) protein family includes a group of homologous nuclear proteins that share a highly conserved plant homeodomain (PHD) finger domain at their carboxyl termini. Members of this family are found in multiprotein complexes that posttranslationally modify histones, suggesting that these proteins serve a general role in permitting various enzymatic activities to interact with nucleosomes. There are three members of the ING family in Saccharomyces cerevisiae: Yng1p, Yng2p, and Pho23p. Yng1p is a component of the NuA3 histone acetyltransferase complex and is required for the interaction of NuA3 with chromatin. To gain insight into the function of the ING proteins, we made use of a genetic strategy to identify genes required for the binding of Yng1p to histones. Using the toxicity of YNG1 overexpression as a tool, we showed that Yng1p interacts with the amino-terminal tail of histone H3 and that this interaction can be disrupted by loss of lysine 4 methylation within this tail. Additionally, we mapped the region of Yng1p required for overexpression of toxicity to the PHD finger, showed that this region capable of binding lysine 4-methylated histone H3 in vitro, and demonstrated that mutations of the PHD finger that abolish binding in vitro are no longer toxic in vivo. These results identify a novel function for the Yng1p PHD finger in promoting stabilization of the NuA3 complex at chromatin through recognition of histone H3 lysine 4 methylation.
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Peffault De Latour, Regis, Simona Sica, Julia Ramos, et al. "COMPOSER Part 4: An Optimized Dosing Strategy for Crovalimab in the Treatment of Complement Inhibitor-Naïve or -Experienced Patients with Paroxysmal Nocturnal Hemoglobinuria." Blood 136, Supplement 1 (2020): 6–7. http://dx.doi.org/10.1182/blood-2020-135841.
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Background Inhibition of complement C5 is the current standard of care for paroxysmal nocturnal hemoglobinuria (PNH). C5 inhibition reduces transfusion requirements and improves anemia and quality of life by ameliorating intravascular hemolysis. However, current therapies require lifelong intravenous infusions at regular intervals, and breakthrough hemolysis may occur due to inadequate C5 inhibition. Crovalimab is a novel anti-human C5 antibody characterized by pH-dependent target binding, enhanced recycling by the neonatal Fc receptor, and high bioavailability, allowing for small-volume (2 × 2 mL) subcutaneous administration every 4 weeks. Part 3 of the Phase I/II COMPOSER study (Sostelly et al. Blood. 2019; Röth et al. Blood. 2020) demonstrated that in patients switched from eculizumab, enhanced crovalimab clearance occurred during the switching phase due to the formation of drug-target-drug complexes, with a risk of temporary loss of complete complement inhibition. Part 4 of COMPOSER tested a dosing regimen optimized to maintain complete complement inhibition in C5 inhibitor-naive patients and those switched from eculizumab to crovalimab. Objectives To evaluate the safety, pharmacokinetic (PK), and pharmacodynamic (PD) effects of an optimized crovalimab regimen. Study Design and Methods Crovalimab is being evaluated in the ongoing Phase I/II COMPOSER study (NCT03157635). Parts 1, 2, and 3 of COMPOSER assessed the PK and safety of crovalimab in healthy volunteers, C5 inhibitor-naive patients, and patients switched from eculizumab, respectively. In Part 4, patients received an intravenous loading series of crovalimab 1000 mg on day 1 followed by 340 mg subcutaneous on days 2, 8, 15, and 22. Maintenance dosing of 680 mg subcutaneous every 4 weeks was started on day 29 (week 5). Plasma concentrations of crovalimab, lactate dehydrogenase (LDH), and free and total C5, as well as complement activity were determined at follow-up visits. The primary endpoints were PK and PD effects of the dosing strategy. Patients were followed up for safety and efficacy, including transfusion avoidance, breakthrough hemolysis events, and hemoglobin stabilization. Results Data for 15 patients (8 naive, 7 switched) treated with the optimized crovalimab dosing strategy in Part 4 are presented here. The data cutoff was January 29, 2020. The PK profiles showed that crovalimab exposure was maintained above the target concentration (100 µg/mL) for complete complement inhibition in all patients, naive and switched. Complete complement inhibition, as measured by liposome immunoassay &lt; 10 U/mL, was achieved immediately following the initial dose and maintained throughout the study treatment period. Consistent with these results, crovalimab-free C5 levels declined rapidly following the initial dose and remained low throughout the follow-up period. As expected based on the target-disposal properties of crovalimab, limited total C5 accumulation was observed in naive patients and a decline was seen in switched patients. Median LDH rapidly declined to ≤ 1.5-fold the upper limit of normal (ULN) in naive patients, remained ≤ 1.5-fold the ULN in switched patients, and remained below this level throughout the observation period in both patient groups (Figure). Crovalimab was well tolerated, and no serious treatment-related adverse events were observed. Conclusions These data showed that the optimized dosing strategy for crovalimab in PNH did not raise any safety concerns and suggest that the strategy results in sustained complete complement inhibition in patients naive to complement inhibitor therapy and those switched from eculizumab. These data support the continued development of crovalimab. Disclosures Peffault De Latour: Alexion Pharmaceuticals Inc.: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Apellis: Membership on an entity's Board of Directors or advisory committees; Amgen: Research Funding; Pfizer: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Novartis: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau. Sica:F. Hoffmann-La Roche Ltd: Other: All authors received support for third-party writing assistance, furnished by Scott Battle, PhD, provided by F. Hoffmann-La Roche, Basel, Switzerland., Research Funding. Ramos:F. Hoffmann-La Roche Ltd: Other: All authors received editorial support for this abstract, provided by Scott Battle, PhD, of Health Interactions and funded by F. Hoffmann-La Roche.; Genentech, Inc: Current Employment, Other: Fellowship support. Hernández-Sánchez:F. Hoffmann-La Roche Ltd: Current Employment, Other: All authors received support for third-party writing assistance, furnished by Scott Battle, PhD, provided by F. Hoffmann-La Roche, Basel, Switzerland.. Kim:Alexion Pharmaceuticals Inc.: Honoraria, Research Funding. Kiialainen:F. Hoffmann-La Roche Ltd: Current Employment, Other: All authors received editorial support for this abstract, provided by Scott Battle, PhD, of Health Interactions and funded by F. Hoffmann-La Roche.. Yoon:F. Hoffmann-La Roche: Other: All authors received support for third-party writing assistance, furnished by Scott Battle, PhD, provided by F. Hoffmann-La Roche, Basel, Switzerland., Research Funding; Janssen: Consultancy; Novartis: Consultancy, Honoraria; YuhanPharma: Research Funding; Amgen: Consultancy, Honoraria; Kyowahako Kirin: Research Funding. Sreckovic:F. Hoffmann-La Roche Ltd: Current Employment, Other: All authors received support for third-party writing assistance, furnished by Scott Battle, PhD, provided by F. Hoffmann-La Roche, Basel, Switzerland.. Soubret:F. Hoffmann-La Roche Ltd: Current Employment, Other: All authors received support for third-party writing assistance, furnished by Scott Battle, PhD, provided by F. Hoffmann-La Roche, Basel, Switzerland.. Ninomiya:F. Hoffmann-La Roche Ltd: Other: All authors received editorial support for this abstract, provided by Scott Battle, PhD, of Health Interactions and funded by F. Hoffmann-La Roche., Research Funding; Alexion: Honoraria; Chugai: Membership on an entity's Board of Directors or advisory committees. Sostelly:F. Hoffmann-La Roche Ltd: Current Employment, Other: All authors received support for third-party writing assistance, furnished by Scott Battle, PhD, provided by F. Hoffmann-La Roche, Basel, Switzerland.. Panse:F. Hoffmann-La Roche Ltd: Consultancy, Membership on an entity's Board of Directors or advisory committees; Boehringer Ingelheim: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Grunenthal: Consultancy, Membership on an entity's Board of Directors or advisory committees; Apellis: Consultancy, Membership on an entity's Board of Directors or advisory committees; Novartis: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; MSD: Consultancy, Membership on an entity's Board of Directors or advisory committees; Alexion: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Blueprint Medicines: Consultancy, Membership on an entity's Board of Directors or advisory committees; Amgen: Consultancy, Membership on an entity's Board of Directors or advisory committees; Chugai: Speakers Bureau; Pfizer: Speakers Bureau; BMS: Consultancy, Membership on an entity's Board of Directors or advisory committees. Buatois:F. Hoffmann-La Roche Ltd: Current Employment, Other: All authors received support for third-party writing assistance, furnished by Scott Battle, PhD, provided by F. Hoffmann-La Roche, Basel, Switzerland.. Schrezenmeier:Alexion Pharmaceuticals Inc.: Honoraria, Research Funding. Paz-Priel:Genentech, Inc: Current Employment; F. Hoffmann-La Roche Ltd: Current equity holder in publicly-traded company, Other: All authors received editorial support for this abstract, provided by Scott Battle, PhD, of Health Interactions and funded by F. Hoffmann-La Roche.. Nishimura:F. Hoffmann-La Roche Ltd: Consultancy, Other: All authors received editorial support for this abstract, provided by Scott Battle, PhD, of Health Interactions and funded by F. Hoffmann-La Roche.; Alexion: Honoraria, Research Funding; Chugai: Consultancy. Röth:Alexion Pharmaceuticals Inc.: Consultancy, Honoraria, Research Funding; Novartis: Consultancy, Honoraria; Roche: Consultancy, Honoraria, Research Funding; Biocryst: Consultancy, Honoraria; Sanofi: Consultancy, Honoraria; Apellis: Consultancy, Honoraria. OffLabel Disclosure: Yes. Crovalimab is an anti-C5 monoclonal antibody being evaluated as a therapy for paroxysmal nocturnal hemoglobinuria
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Takahashi, Eiji, and Michihiko Sato. "Anaerobic respiration sustains mitochondrial membrane potential in a prolyl hydroxylase pathway-activated cancer cell line in a hypoxic microenvironment." American Journal of Physiology-Cell Physiology 306, no. 4 (2014): C334—C342. http://dx.doi.org/10.1152/ajpcell.00255.2013.
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To elucidate how tumor cells produce energy in oxygen-depleted microenvironments, we studied the possibility of mitochondrial electron transport without oxygen. We produced well-controlled oxygen gradients (ΔO2) in monolayer-cultured cells. We then visualized oxygen levels and mitochondrial membrane potential (ΔΦm) in individual cells by using the red shift of green fluorescent protein (GFP) fluorescence and a cationic fluorescent dye, respectively. In this two-dimensional tissue model, ΔΦm was abolished in cells >500 μm from the oxygen source [the anoxic front (AF)], indicating limitations in diffusional oxygen delivery. This result perfectly matched GFP-determined ΔO2. In cells pretreated with dimethyloxaloylglycine (DMOG), a prolyl hydroxylase domain-containing protein (PHD) inhibitor, the AF was expanded to 1,500–2,000 μm from the source. In these cells, tissue ΔO2 was substantially decreased, indicating that PHD pathway activation suppressed mitochondrial respiration. The expansion of the AF and the reduction of ΔO2 were much more prominent in a cancer cell line (Hep3B) than in the equivalent fibroblast-like cell line (COS-7). Hence, the results indicate that PHD pathway-activated cells can sustain ΔΦm, despite significantly decreased electron flux to complex IV. Complex II inhibition abolished the effect of DMOG in expanding the AF, although tissue ΔO2 remained shallow. Separate experiments demonstrated that complex II plays a substantial role in sustaining ΔΦm in DMOG-pretreated Hep3B cells with complex III inhibition. From these results, we conclude that PHD pathway activation can sustain ΔΦm in an otherwise anoxic microenvironment by decreasing tissue ΔO2 while activating oxygen-independent electron transport in mitochondria.
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He, Qiuping, Mengzhi Hong, Jincan He, Weixin Chen, Meng Zhao, and Wei Zhao. "Isoform-specific involvement of Brpf1 in expansion of adult hematopoietic stem and progenitor cells." Journal of Molecular Cell Biology 12, no. 5 (2019): 359–71. http://dx.doi.org/10.1093/jmcb/mjz092.
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Abstract Bromodomain-containing proteins are known readers of histone acetylation that regulate chromatin structure and transcription. Although the functions of bromodomain-containing proteins in development, homeostasis, and disease states have been well studied, their role in self-renewal of hematopoietic stem and progenitor cells (HSPCs) remains poorly understood. Here, we performed a chemical screen using nine bromodomain inhibitors and found that the bromodomain and PHD finger-containing protein 1 (Brpf1) inhibitor OF-1 enhanced the expansion of Lin−Sca-1+c-Kit+ HSPCs ex vivo without skewing their lineage differentiation potential. Importantly, our results also revealed distinct functions of Brpf1 isoforms in HSPCs. Brpf1b promoted the expansion of HSPCs. By contrast, Brpf1a is the most abundant isoform in adult HSPCs but enhanced HSPC quiescence and decreased the HSPC expansion. Furthermore, inhibition of Brpf1a by OF-1 promoted histone acetylation and chromatin accessibility leading to increased expression of self-renewal-related genes (e.g. Mn1). The phenotypes produced by OF-1 treatment can be rescued by suppression of Mn1 in HSPCs. Our findings demonstrate that this novel bromodomain inhibitor OF-1 can promote the clinical application of HSPCs in transplantation.
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Ueno, Manabu, Toshitaka Maeno, Miyuki Nomura та ін. "Hypoxia-inducible factor-1α mediates TGF-β-induced PAI-1 production in alveolar macrophages in pulmonary fibrosis". American Journal of Physiology-Lung Cellular and Molecular Physiology 300, № 5 (2011): L740—L752. http://dx.doi.org/10.1152/ajplung.00146.2010.
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Hypoxia-inducible factor-1α (HIF-1α), a transcription factor that functions as a master regulator of oxygen homeostasis, has been implicated in fibrinogenesis. Here, we explore the role of HIF-1α in transforming growth factor-β (TGF-β) signaling by examining the effects of TGF-β1on the expression of plasminogen activator inhibitor-1 (PAI-1). Immunohistochemistry of lung tissue from a mouse bleomycin (BLM)-induced pulmonary fibrosis model revealed that expression of HIF-1α and PAI-1 was predominantly induced in alveolar macrophages. Real-time RT-PCR and ELISA analysis showed that PAI-1 mRNA and activated PAI-1 protein level were strongly induced 7 days after BLM instillation. Stimulation of cultured mouse alveolar macrophages (MH-S cells) with TGF-β1induced PAI-1 production, which was associated with HIF-1α protein accumulation. This accumulation of HIF-1α protein was inhibited by SB431542 (type I TGF-β receptor/ALK receptor inhibitor) but not by PD98059 (MEK1 inhibitor) and SB203580 (p38 MAP kinase inhibitor). Expression of prolyl-hydroxylase domain (PHD)-2, which is essential for HIF-1α degradation, was inhibited by TGF-β1, and this decrease was abolished by SB431542. TGF-β1induction of PAI-1 mRNA and its protein expression were significantly attenuated by HIF-1α silencing. Transcriptome analysis by cDNA microarray of MH-S cells after HIF-1α silencing uncovered several pro-fibrotic genes whose regulation by TGF-β1required HIF-1α, including platelet-derived growth factor-A. Taken together, these findings expand our concept of the role of HIF-1α in pulmonary fibrosis in mediating the effects of TGF-β1on the expression of the pro-fibrotic genes in activated alveolar macrophages.
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Mannick, Joan, Amelia Tomlinson, Sarb Shergill, Grace Teo, and Lloyd Klickstein. "LB2. TORC1 Inhibition with RTB101 as a Potential Pan-Antiviral Immunotherapy to Decrease the Incidence of Respiratory Tract Infections Due to Multiple Respiratory Viruses in Older Adults." Open Forum Infectious Diseases 6, Supplement_2 (2019): S993—S994. http://dx.doi.org/10.1093/ofid/ofz415.2485.
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Abstract Background Respiratory tract infections (RTIs) are a leading cause of hospitalization and death in people age ≥65 years. RTIs are caused by multiple viruses, most of which lack effective treatments. An immunotherapy that enhances pan-antiviral innate immunity may reduce RTI incidence in older adults. Inhibition of targets downstream of target of rapamycin complex 1 (TORC1) was reported to upregulate pan-antiviral gene expression and protect mice from a viral RTI (York AG et al. Cell 2015). We evaluated whether TORC1 inhibition increased antiviral gene expression and decreased RTI incidence in older adults. Methods A randomized, double-blind, placebo, controlled study was conducted to determine whether the TORC1 inhibitor RTB101 alone or in combination with the TORC1 inhibitor everolimus reduced the incidence of laboratory-confirmed RTIs. The study enrolled 652 older adults at increased risk of RTI-related morbidity and mortality (defined as age ≥85 years, or age ≥65 years with asthma, COPD, type 2 diabetes mellitus, or current smokers). Subjects were treated for 16 weeks during winter cold and flu season with oral RTB101 5 mg or 10 mg once daily (QD), RTB101 10 mg twice daily, RTB101 10 mg + everolimus 0.1 mg QD, or matched placebo. The primary endpoint was the percentage of subjects with ≥1 laboratory-confirmed RTI through Week 16. Results RTB101 was well tolerated. In the intent-to-treat analysis, RTB101 10 mg QD was observed to: reduce the percentage of subjects with laboratory-confirmed RTIs by 30.6% compared with placebo (P = 0.025); reduce the incidence of RTIs caused by multiple different viruses; and upregulate interferon-stimulated pan-antiviral gene expression in whole blood (P = 0.00001 vs. placebo, Figure 1). Furthermore, RTB101 10 mg QD was observed to reduce the time to alleviation of moderate to severe RTI symptoms by 5 days, and to reduce the rate of all-cause hospitalization (rate ratio 0.439, 90% CI 0.196–0.983, P = 0.047). Conclusion RTB101 10 mg QD was associated with a significant reduction in laboratory-confirmed RTIs due to multiple viral pathogens that lack effective medicines for treatment or prevention. RTB101 was observed to upregulate interferon-stimulated pan-antiviral gene expression, which may underlie the reduction in RTI incidence. Disclosures Joan Mannick, MD, resTORbio (Employee, Shareholder), Amelia Tomlinson, PhD, resTORbio (Employee), Sarb Shergill, PhD, resTORbio (Employee), Grace Teo, PhD, resTORbio (Employee), Lloyd Klickstein, MD, PhD, resTORbio (Employee).
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Suhara, Tomohiro, Takako Hishiki, Masataka Kasahara, et al. "Inhibition of the oxygen sensor PHD2 in the liver improves survival in lactic acidosis by activating the Cori cycle." Proceedings of the National Academy of Sciences 112, no. 37 (2015): 11642–47. http://dx.doi.org/10.1073/pnas.1515872112.
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Loss of prolyl hydroxylase 2 (PHD2) activates the hypoxia-inducible factor-dependent hypoxic response, including anaerobic glycolysis, which causes large amounts of lactate to be released from cells into the circulation. We found that Phd2-null mouse embryonic fibroblasts (MEFs) produced more lactate than wild-type MEFs, as expected, whereas systemic inactivation of PHD2 in mice did not cause hyperlacticacidemia. This unexpected observation led us to hypothesize that the hypoxic response activated in the liver enhances the Cori cycle, a lactate–glucose carbon recycling system between muscle and liver, and thereby decreases circulating lactate. Consistent with this hypothesis, blood lactate levels measured after a treadmill or lactate tolerance test were significantly lower in Phd2-liver-specific knockout (Phd2-LKO) mice than in control mice. An in vivo 13C-labeled lactate incorporation assay revealed that the livers of Phd2-LKO mice produce significantly more glucose derived from 13C-labeled lactate than control mice, suggesting that blockade of PHD2 in the liver ameliorates lactic acidosis by activating gluconeogenesis from lactate. Phd2-LKO mice were resistant to lactic acidosis induced by injection of a lethal dose of lactate, displaying a significant elongation of survival. Moreover, oral administration of a PHD inhibitor improved survival in an endotoxin shock mice model. These data suggest that PHD2 is a potentially novel drug target for the treatment of lactic acidosis, which is a serious and often fatal complication observed in some critically ill patients.
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Kazmierczak, Krystyna, Sibylle Lob, Greg Stone, and Daniel F. Sahm. "1569. In Vitro Activity of Ceftazidime-avibactam and Comparator Agents against Enterobacterales and Pseudomonas aeruginosa Collected from Patients with Bloodstream Infections as Part of the ATLAS Global Surveillance Program, 2015-2018." Open Forum Infectious Diseases 7, Supplement_1 (2020): S783—S784. http://dx.doi.org/10.1093/ofid/ofaa439.1749.
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Abstract Background Avibactam (AVI) is a β-lactamase inhibitor with potent inhibitory activity against Class A, Class C, and some Class D serine β-lactamases. The combination of ceftazidime (CAZ) with AVI has been approved in Europe and in the United States for several indications. This study evaluated the in vitro activity of CAZ-AVI and comparators against Enterobacterales (Eba) and Pseudomonas aeruginosa (Pae) isolates collected from patients with bloodstream infections as part of the ATLAS surveillance program in 2015-2018. Methods A total of 57048 Eba and 15813 Pae non-duplicate clinically significant isolates, including 7720 Eba and 1286 Pae isolated from bloodstream infections, were collected in 52 countries in Europe, Latin America, Asia/Pacific (excluding mainland China), and the Middle East/Africa region. Susceptibility testing was performed by CLSI broth microdilution. CAZ-AVI was tested at a fixed concentration of 4 µg/ml AVI. Meropenem-nonsusceptible (MEM-NS) Eba and Pae isolates were screened for the presence of β-lactamase genes. Results Susceptibility data are shown in the Table. Percentages of susceptibility (% S) to the tested agents were 0.3-2.9% lower among Eba and Pae from bloodstream infections compared to isolates from combined sources in most cases. CAZ-AVI showed potent in vitro activity against all Eba bloodstream isolates and the CAZ-NS subset (MIC90, 0.5-2 µg/ml, 93.4-98.1% S). Reduced activity against MEM-NS Eba was attributable to carriage of class B metallo-β-lactamases (MBLs) because 99% of MEM-NS MBL-negative isolates were susceptible to CAZ-AVI. None of the tested comparators exceeded the activity of CAZ-AVI. CAZ-AVI also showed good in vitro activity against the majority of Pae bloodstream isolates (MIC90, 16 µg/ml, 89.4% S). Activity was reduced against CAZ-NS and MEM-NS subsets (54.2-63.8% S), which included isolates carrying MBLs, but exceeded the activity of CAZ and MEM against these subsets by 26-31 percentage points. Amikacin was the only tested comparator that demonstrated comparable activity against Pae bloodstream isolates. Table Conclusion CAZ-AVI provides a valuable therapeutic option for treating bloodstream infections caused by MBL-negative Eba and Pae isolates. Disclosures Krystyna Kazmierczak, PhD, IHMA (Employee)Pfizer, Inc. (Consultant) Sibylle Lob, PhD, IHMA (Employee)Pfizer, Inc. (Consultant) Greg Stone, PhD, AztraZeneca (Shareholder, Former Employee)Pfizer, Inc. (Employee) Daniel F. Sahm, PhD, IHMA (Employee)Pfizer, Inc. (Consultant)Shionogi & Co., Ltd. (Independent Contractor)
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Yang, Yunwen, Xiaowen Yu, Yue Zhang, et al. "Hypoxia-inducible factor prolyl hydroxylase inhibitor roxadustat (FG-4592) protects against cisplatin-induced acute kidney injury." Clinical Science 132, no. 7 (2018): 825–38. http://dx.doi.org/10.1042/cs20171625.
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Renal hypoxia occurs in acute kidney injury (AKI) of various etiologies. Activation of hypoxia-inducible transcription factor (HIF) has been identified as an important mechanism of cellular adaptation to low oxygen. Preconditional HIF activation protects against AKI, suggesting a new approach in AKI treatment. HIF is degraded under normoxic conditions mediated by oxygen-dependent hydroxylation of specific prolyl residues of the regulative α-subunits by HIF prolyl hydroxylases (PHD). FG-4592 is a novel, orally active, small-molecule HIF PHD inhibitor for the treatment of anemia in patients with chronic kidney disease (CKD). The current study aimed to evaluate the effect of FG-4592 (Roxadustat) on cis-diamminedichloroplatinum (cisplatin)-induced kidney injury. In mice, pretreatment with FG-4592 markedly ameliorated cisplatin-induced kidney injury as shown by the improved renal function (blood urea nitrogen (BUN), serum creatinine (Scr), and cystatin C) and kidney morphology (periodic acid-Schiff (PAS) staining) in line with a robust blockade of renal tubular injury markers of kidney injury molecule 1 (KIM-1) and neutrophil gelatinase-associated lipocalin (NGAL). Meanwhile, the renal apoptosis and inflammation induced by cisplatin were also strikingly attenuated in FG-4592-treated mice. Along with the protective effects shown above, FG-4592 pretreatment strongly enhanced HIF-1α in tubular cells, as well as the expressions of HIF target genes. FG-4592 alone did not affect the renal function and morphology in mice. In vitro, FG-4592 treatment significantly up-regulated HIF-1α and protected the tubular cells against cisplatin-induced apoptosis. In summary, FG-4592 treatment remarkably ameliorated the cisplatin-induced kidney injury possibly through the stabilization of HIF. Thus, besides the role in treating CKD anemia, the clinical use of FG-4592 also could be extended to AKI.
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Zhang, Anqi, Daisuke Nakano, Norihiko Morisawa, and Akira Nishiyama. "Effects of molidustat, a HIF-PHD inhibitor, on sodium dynamics and distribution in hypertensive subtotally nephrectomized rats." Proceedings for Annual Meeting of The Japanese Pharmacological Society 94 (2021): 2—O—D3–3. http://dx.doi.org/10.1254/jpssuppl.94.0_2-o-d3-3.
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Kazmierczak, Krystyna, Francis Arhin, Greg Stone, and Daniel F. Sahm. "1567. In Vitro Activity of Aztreonam-Avibactam and Comparator Agents Against Multidrug-Resistant Enterobacterales Collected Globally as Part of the ATLAS Surveillance Program, 2016-2018." Open Forum Infectious Diseases 7, Supplement_1 (2020): S783. http://dx.doi.org/10.1093/ofid/ofaa439.1747.
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Abstract Background Avibactam (AVI) is a serine-β-lactamase inhibitor in development with aztreonam (ATM) for treatment of infections caused by drug-resistant Enterobacterales (Ent), especially carbapenem-resistant isolates co-producing serine- and metallo-β-lactamases (MBL), which are often resistant to agents from multiple drug classes. This study evaluated the in vitro activity of ATM-AVI and comparators against Ent collected globally as part of the Antimicrobial Testing Leadership and Surveillance (ATLAS) program. Methods 44,671 non-duplicate clinical isolates were collected in 2016-2018 in 52 countries in Europe, Asia/Pacific (excluding China and India), Middle East/Africa, and Latin America. Susceptibility testing was performed by CLSI broth microdilution and interpreted using CLSI 2020 and FDA (tigecycline) breakpoints. ATM-AVI was tested at a fixed concentration of 4 µg/mL AVI. Drug-resistant phenotypes were defined as: multidrug resistant (MDR), resistant (R) to ≥3 of 7 sentinel agents (amikacin [AMK], ATM, cefepime [FEP], colistin [CST], levofloxacin [LVX], meropenem [MEM], piperacillin-tazobactam [TZP]); extensively drug resistant (XDR), susceptible to ≤2 sentinel agents; and pandrug resistant (PDR), non-susceptible to all sentinel agents. Isolates with MEM MIC &gt;1 µg/mL were screened for β-lactamase genes by PCR and sequencing. Results 14.9%, 4.3%, 3.7%, 1.3%, and 0.3% of Ent collected globally were MDR, XDR, MEM-R, MBL-positive, and PDR, respectively. ATM-AVI tested with MIC90 values of 0.12 µg/mL against all Ent and 0.5 µg/mL against subsets of resistant isolates (Table). On the regional level, similar values were observed against all (MIC90, 0.12 µg/mL) and resistant isolates (MIC90, 0.25-1 µg/mL) (not shown). The tested comparators, excluding TGC, showed percentages of susceptibility &lt; 90% against regional and global subsets of resistant isolates. 99.97% (44658 of 44671) Ent, including all MBL-positive and PDR isolates, were inhibited by ≤8 µg/mL of ATM-AVI. Table Conclusion Based on MIC90 values, ATM-AVI demonstrated potent in vitro activity against resistant and MBL-positive subsets of Ent collected globally. ATM-AVI could be an effective therapy for difficult-to-treat infections caused by drug-resistant Ent. Disclosures Krystyna Kazmierczak, PhD, IHMA (Employee)Pfizer, Inc. (Consultant) Francis Arhin, PhD, Pfizer, Inc. (Employee) Greg Stone, PhD, AztraZeneca (Shareholder, Former Employee)Pfizer, Inc. (Employee) Daniel F. Sahm, PhD, IHMA (Employee)Pfizer, Inc. (Consultant)Shionogi & Co., Ltd. (Independent Contractor)
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Matsunaga, Shinji, Shunji Nishide, Kentaro Tokudome, Takehiro Yamaguchi, and Shuhei Tomita. "Phenotypic alteration of tumor infiltrating macrophage by PHD inhibitor lead to improve tumor microenvironment in vivo mouse model." Proceedings for Annual Meeting of The Japanese Pharmacological Society 93 (2020): 1—O—006. http://dx.doi.org/10.1254/jpssuppl.93.0_1-o-006.
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Döhrmann, Simon, Amanda Almaguer, Nicholas Dedeic, et al. "162. CD377, a Novel Antiviral Fc-conjugate, Demonstrates Potent Viral Burden Reduction Against Influenza a (H1N1) in Mouse and Ferret Models." Open Forum Infectious Diseases 7, Supplement_1 (2020): S210—S211. http://dx.doi.org/10.1093/ofid/ofaa439.472.
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Abstract Background AVCs (antiviral Fc-conjugates) are novel, long-acting immunotherapeutic conjugates of potent antivirals conjugated to the Fc domain of human IgG1. CD377, an AVC development candidate for the prevention and treatment of influenza A and B, comprises multiple copies of a novel neuraminidase inhibitor conjugated to IgG1 Fc. CD377 demonstrated potent, broad-spectrum activity in vitro and in lethal mouse models. Herein, we characterize the activity of CD377 on viral lung burden in lethal mouse models and in a ferret model of influenza A (H1N1) infection. Methods BALB/c mice were challenged intranasally with 3 x 102 PFU of influenza A/PR/8/1934 (H1N1) or with 3 x 104 PFU A/CA/07/2009 (H1N1)pdm. Ferrets were challenged sub-lethally at 1 x 106 PFU with influenza A/CA/07/2009 (H1N1)pdm. A single dose of CD377 was given 2 h post-challenge in the mouse (subcutaneous dose ranging from 0.1 – 3 mg/kg) or 24 h prior to challenge in the ferret (intravenous dose ranging from 0.3 – 30 mg/kg). In mice, oral oseltamivir was given at 5 mg/kg (human equivalent dose, HED) or at 50 mg/kg BID x 4 days starting at 2 h post-challenge and in ferrets at 20 mg/kg (4x HED) BID x 4 days starting at 4 h prior to infection. Viral burden was determined on day 4 (mouse) or days 2 and 4 (ferret) post-challenge by plaque assay. Results In mice, CD377 demonstrated dose-dependent reduction in viral lung burden (1.1 logs at 0.1 mg/kg, 2.1 logs at 0.3 mg/kg, 3.1 logs at 1 mg/kg and 3.6 logs at 3 mg/kg) compared to PBS against influenza A/PR/8/1934 (H1N1) (Fig. 1A). In the same study, oseltamivir reduced viral lung burden only by 0.8 logs at both 5 mg/kg (HED) and 50 mg/kg. No significant reduction in lung burden was observed between negative controls, PBS and hIgG1 Fc. Similarly, CD377 demonstrated a dose-dependent, multi-log reduction in viral lung burden against influenza A/CA/07/2009 (H1N1)pdm (Fig. 1B). In ferrets, CD377 reduced viral load with dose dependency at days 2 (Fig. 1C) and 4 post-infection (Fig. 1D). CD377 at 3 mg/kg or higher dose was superior compared to oseltamivir at 4x HED on days 2 and 4 post-challenge. Conclusion CD377 demonstrated superior viral load reduction compared to oseltamivir in lethal influenza A (H1N1) mouse and ferret models. These data support further development of CD377 for prevention and treatment of influenza infection. Disclosures Simon Döhrmann, PhD, Cidara Therapeutics (Shareholder) Amanda Almaguer, Bachelors, Cidara Therapeutics, Inc. (Employee, Shareholder) Nicholas Dedeic, n/a, Cidara Therapeutics (Employee) Karin Amundson, BSc, Cidara Therapeutics (Shareholder) Thomas P. Brady, PhD Chemistry, Cidara Therapeutics (Employee) Alain Noncovich, PhD, Cidara Therapeutics (Shareholder) Grayson Hough, MS - Chemistry, Cidara Therapeutics (Employee) Allen Borchardt, PhD, Cidara Therapeutics (Employee) Jeffrey B. Locke, PhD, Cidara Therapeutics, Inc. (Employee, Shareholder) Jason Cole, PhD, Cidara Therapeutics (Shareholder) James Levin, PhD, Cidara Therapeutics (Shareholder) Les Tari, PhD, Cidara Therapeutics (Shareholder)
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Ahmed, Shakil, Carmela Palermo, Shanhong Wan, and Nancy C. Walworth. "A Novel Protein with Similarities to Rb Binding Protein 2 Compensates for Loss of Chk1 Function and Affects Histone Modification in Fission Yeast." Molecular and Cellular Biology 24, no. 9 (2004): 3660–69. http://dx.doi.org/10.1128/mcb.24.9.3660-3669.2004.
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ABSTRACT The conserved protein kinase Chk1 mediates cell cycle progression and consequently the ability of cells to survive when exposed to DNA damaging agents. Cells deficient in Chk1 are hypersensitive to such agents and enter mitosis in the presence of damaged DNA, whereas checkpoint-proficient cells delay mitotic entry to permit time for DNA repair. In a search for proteins that can improve the survival of Chk1-deficient cells exposed to DNA damage, we identified fission yeast Msc1, which is homologous to a mammalian protein that binds to the tumor suppressor Rb (RBP2). Msc1 and RBP2 each possess three PHD fingers, domains commonly found in proteins that influence the structure of chromatin. Msc1 is chromatin associated and coprecipitates a histone deacetylase activity, a property that requires the PHD fingers. Cells lacking Msc1 have a dramatically altered histone acetylation pattern, exhibit a 20-fold increase in global acetylation of histone H3 tails, and are readily killed by trichostatin A, an inhibitor of histone deacetylases. We postulate that Msc1 plays an important role in regulating chromatin structure and that this function modulates the cellular response to DNA damage.
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Garey, Kevin W., Kevin W. Garey, Martin Kankam, et al. "LB7. A Randomized, Blinded, Placebo- and Vancomycin-Controlled, First-In-Human (FIH) Study of the Safety, Pharmacokinetics (PK), and Fecal Microbiome Effects of ACX-362E, a Novel Anti-Clostridial DNA Polymerase IIIC (polIIIC) Inhibitor." Open Forum Infectious Diseases 6, Supplement_2 (2019): S995—S996. http://dx.doi.org/10.1093/ofid/ofz415.2490.
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Abstract Background ACX-362E, a novel DNA polIIIC inhibitor, is a narrow-spectrum antibacterial selectively active against certain Gram-positive bacteria, including Clostridioides difficile (MIC90 = 4 µg/mL). The objectives of this phase I study was to assess the safety, pharmacokinetics, and fecal microbiome effects of ACX-362E Methods This three-part FIH phase 1, double-blind, randomized healthy volunteer trial determined the safety profile, food effect, and systemic/stool pharmacokinetics of escalating single (150, 300, 600, and 900 mg) and multiple (300 and 450 mg) doses of oral ACX-362E vs. placebo (PBO). Fecal microbiome effects (metagenomic sequencing and qPCR) of multiple-dose ACX-362E were compared with 6 subjects receiving concomitant open-label vancomycin 125 mg four times daily. Dose escalation to each new cohort occurred following review of safety and PK data by a safety oversight committee. Results Forty-four subjects received ACX-362E (single dose = 24, multiple doses = 12, food effect = 8) and 12 PBO. Overall, ACX-362E was well tolerated at all dose levels. Adverse events were generally mild and transitory, and no moderate, severe, cumulative, or dose-limiting drug-related adverse events leading to discontinuation were observed. Mean plasma half-life was approximately 2 hours and no accumulation occurred with repeated dosing (Figure 1). Systemic exposure was less than 1 μg/mL and decreased with food. Fecal concentrations during multiple dosing exceeded the C. difficile MIC by multiples of up to ~2,500. ACX-362E had minimal effect on Bacteroidetes phylum and caused significantly less dysbiosis than vancomycin (Figure 2). Conclusion This FIH clinical trial with ACX-362E demonstrated a favorable safety profile, low systemic and high fecal concentrations, and favorable gut microbiome changes compared with vancomycin. These results shows promise for further clinical development to treat C. difficile infections. Disclosures Kevin W. Garey, MS, PharmD, Acurx (Grant/Research Support), Martin Kankam, MD, PhD, MPH, Acurx Pharmaceuticals, LLC (Research Grant or Support), Julie Mercier, BS, Acurx Pharmaceuticals, LLC (Research Grant or Support), Corinne Seng Yue, BPharm, MSc, PhD, Acurx Pharmaceuticals, LLC (Grant/Research Support), Murray Ducharme, PharmD, Acurx Pharmaceuticals, LLC (Grant/Research Support), Anne J. Gonzales-Luna, PharmD, no financial relationships or conflicts of interest, M Jahangir Alam, PhD, No financial relationships or conflicts of interest, Khurshida Begum, PhD, No financial relationships or conflicts of interest, Michael Silverman, MD, Acurx Pharmaceuticals, LLC (Consultant, Employee, Shareholder).
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Krishnakumari, Viswanatha, Nandini Rangaraj, and Ramakrishnan Nagaraj. "Antifungal Activities of Human Beta-Defensins HBD-1 to HBD-3 and Their C-Terminal Analogs Phd1 to Phd3." Antimicrobial Agents and Chemotherapy 53, no. 1 (2008): 256–60. http://dx.doi.org/10.1128/aac.00470-08.
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ABSTRACT The activities of defensins HBD-1, HBD-2, and HBD-3 and their C-terminal analogs Phd1, Phd2, and Phd3 against Candida albicans were investigated. Phd1 to Phd3 showed lower-level activities than HBD-1 to HBD-3, although metabolic inhibitors did not render Phd1 to Phd3 inactive. Their activities were also less salt sensitive than those of HBD-1 to HBD-3. Confocal microscope images indicated that the initial site of action was the fungal membrane.
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Akinsiku, Oluwayimika E., Opeyemi S. Soremekun, Fisayo A. Olotu, and Mahmoud E. S. Soliman. "Exploring the Role of Asp1116 in Selective Drug Targeting of CREBcAMP- Responsive Element-binding Protein Implicated in Prostate Cancer." Combinatorial Chemistry & High Throughput Screening 23, no. 3 (2020): 178–84. http://dx.doi.org/10.2174/1386207323666200219122057.
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Background: The selective targeting of CREB-cAMP-responsive element-binding protein (CBP) has recently evolved as a vital therapeutic approach for curtailing its aberrant upregulation associated with the development of prostate cancer. Inhibition of CBP has been discovered to be an important therapeutic option in androgen receptor signalling pathway mediated prostate cancer. Y08197, a novel selective inhibitor of CBP, has shown promising therapeutic outcome in prostate carcinogenesis over non-selective analogues such as CPI-637. Methods/Results: Herein, we used molecular dynamics simulation to gain insights into the mechanistic and selective targeting of Y08197 at the bromodomain active site. Molecular Mechanics/ Poisson-Boltzmann Surface Area (MM/PBSA) analysis revealed a similar inhibitory effect between Y08197 and CPI-637. Furthermore, in exploring the selective affinity of Y08197 towards CBP in combination with Bromodomain and PHD finger-containing protein 1(BRPF1), our findings highlighted Asp1116 as the ‘culprit’ residue responsible for this selective targeting. Upon binding, Asp1116 assumed a conformation that altered the architecture of the bromodomain active site, thereby orienting the helices around the active site in a more compacted position. In addition to some specific structural perturbations mediated by Asp1116 on the dynamics of CBP, our study revealed that the strong hydrogen bond interaction (N-H...O) elicited in CBP-Y08197 sequestered Y08197 tightly into the CBP bromodomain active site. Conclusion: Conclusively, the inhibition and selective pattern of Y08197 can be replicated in future structure-based CBP inhibitors and other bromodomain implicated in carcinogenesis.