Academic literature on the topic 'HTRA1 [HtrA serine peptisade 1]'

The mammalian HtrA family consists of serine proteases with distinct domains homologous to the bacterial high temperature requirement factor (HtrA). Three human HtrA members have been reported: HtrA1 (PRSS11 or L56), HtrA2 (OMI) and HtrA3 (PRSP). The function of HtrA1 is not well characterised, but it has been shown to be downregulated in malignant tissues (1–3) indicating that the downregulation of HtrA1 is associated with cancer progression. HtrA2 regulates apoptosis by interacting with X-linked inhibitors of apoptosis (XIAP) thus preventing the caspase-inhibitory function of XIAP (4). The function of newly identified HtrA3 is not known, however it shares a high degree of sequence and domain homologies with HtrA1 and may therefore share a functional similarity with HtrA1 (5). Endometrial cancer (EC) is a prevalent gynaecological cancer, commonly affecting women after menopause. In this study we examined the expression of HtrA1, 2 and 3 in EC. Reverse transcriptase-PCR (semi-quantitative) analysis showed decreased mRNA expression of both HtrA1 and HtrA3, but no significant change for HtrA2, in EC tissue samples compared to normal endometrium. We then determined the protein level of expression and the cellular localisation of all three HtrA members in EC progression using immunohistochemistry. HtrA1 and HtrA3 showed a similar pattern of expression and both decreased dramatically with the progression of cancer from grade 1 through to 3. Surprisingly, HtrA2 protein expression was also decreased with cancer progression, but the decline was not as dramatic as that for HtrA1 and HtrA3. Interestingly, considerably less staining was observed for all three HtrA proteins in grade 3 cancer tissues. These data suggest that decreased expression of HtrA proteins, particularly HtrA1 and HtrA3, is associated with the progression of endometrial cancer. (1) Nie, G., Hampton, A., Li, Y., Findlay, J., Salamonsen, L.A. (2003) Identification and cloning of two isoforms of human high-temperature requirement factor A3 (HtrA3), characterization of its genomic structure and comparison of its tissue distribution with HtrA1 and HtrA2. Biochem. J. 371, 39–48. (2) van Loo, G., van Gurp, M., Depuydt, B., Srinivasula, S.M., Rodriguez, I., Alnemri, E.S., Gevaert, K., Vandekerckhove, J., Declercq, W., Vandenabeele, P. (2002) The serine protease OMI/HtrA2 is released from mitochondria during apoptosis. OMI interacts with caspase-inhibitor XIAP and induces enhanced caspase activity. Cell Death Diff. 9, 20–26. (3) Chien, J., Staub, J., Hu, S., Erickson-Johnson, M.R., Couch, F.J., Smith, D.I., Crowl, R.M., Kaufmann, S., Shridhar, V. (2004) A candidate tumour supressor HtrA1 is down-regulated in ovarian cancer. Oncogene 23, 1636–1644. (4) Shridhar, V., Sen, A., Chien, J., Staub, J., Avula, R., Kovats, S., Lee, J., Lillie, J., Smith, D.I. (2002) Identification of underexpressed genes in early- and late-stage primary ovarian tumours by suppression subtraction hybridization. Cancer Res. 62, 262–270. (5) Baldi, A., De Luca, A., Morini, M., Battista, T., Felsani, A., Baldi, F., Catricala, C., Amantea, A., Noonan, D. M., Albini, A., Ciorgio, P., Lombardi, D., Paggi, M. G. (2002) The HtrA1 serine protease is down-regulated during human melanoma progression and represses growth of metastatic melanoma cells. Oncogene 21, 6684–6688.

Abstract BACKGROUND: Neutrophil extracellular traps (NET) are extracellular lattices of decondensed chromatin associated with anti-microbial proteins and degradative enzymes released by polymorphonuclear leukocytes (PMN) to trap and kill invading microbes. Dysregulated NET formation, however, contributes to inflammatory tissue damage. We have identified a novel NET-inhibitory peptide, neonatal NET-Inhibitory Factor (nNIF), present in the fetal circulation. nNIF is formed as a carboxy-terminus cleavage fragment of alpha-1 antitrypsin (AAT), an abundant, circulating protease inhibitor with homologs in human and mouse blood. However, the exact mechanisms by which nNIF is generated in fetal and neonatal blood remains unknown. OBJECTIVE: High temperature requirement A 1 (HTRA1) is expressed in the placenta during fetal development and inhibits AAT. We hypothesized that placentally expressed HTRA1, a serine protease, regulates the formation of NET-inhibitory peptides, such as nNIF, through cleavage of AAT. DESIGN/METHODS: Term and preterm placenta were lysed and probed for HTRA1 expression. HTRA1 and AAT plasma expression from term and preterm infants and adults were determined by ELISA. Recombinant, bioactive HTRA1 or placenta-eluted HTRA1 were incubated with AAT and the generation of carboxy-terminus fragments of AAT was assessed using western blotting and mass spectrometry. Fragments of AAT generated by HTRA1 were incubated with LPS-stimulated PMNs and NET formation was examined qualitatively using live cell imaging and quantitatively using a high throughput fluorescence assay. The effect of the HTRA-AAT cleavage fragment on reactive oxygen species generation, neutrophil chemotaxis, phagocytosis, and bacterial killing was measured using flow cytometry, a modified Boyden chamber asssay, neutrophil labeled Escherichia coli uptake assay, and a bacterial killing assay with a pathogenic strain of Escherichia coli, respectively. Finally, NET formation was evaluated qualitatively and quantitatively in murine PMNs isolated from neonatal WT and HTRA1-/- pups between 1-3, 4-6 and 7-10 days after birth to determine when PMNs become NET-competent. RESULTS: Term and preterm infant placentas express HTRA1, and we detected significantly (p<0.05) higher levels of HTRA1 in plasma from term (465.1±71.8 µg/mL) and preterm (385.9±71.3 µg/mL) infant cord blood compared to adults (58.6±11.6 µg/mL). Recombinant, bioactive HTRA1 and placenta-derived HTRA1 incubated with AAT generate a 4kD AAT fragment based on western blot and mass spectrometry similar to the nNIF fragment found in cord blood from term and preterm infants. Pre-incubation of this fragment with LPS-stimulated PMNs significantly inhibits NET formation (p<0.05). The cleavage fragment from HTRA1-AAT, however, has no effect on reactive oxygen species generation, chemotaxis, or phagocytosis. However, incubation of this fragment with LPS-stimulated PMNs significantly (p<0.05) reduces NET-associated bacterial killing by 62% compared to a scrambled HTRA-AAT control peptide. In addition, the HTRA1-AAT fragment significantly (p<0.05) reduces nuclear decondensation by 93% compared to LPS-stimulated PMN, suggesting this fragment inhibits PAD4 activation similar to other NIFs previously examined. Neonatal murine plasma contains a 4kD AAT fragment which inhibits NET formation by adult mouse PMNs, indicating that nNIF generation is conserved in mice. Neonatal PMNs stimulated with LPS exhibit delayed NET formation following birth with PMNs becoming NET-competent by day 8 of life. However, neonatal PMNs from pups born from HTRA1-/- deficient mice generate significantly (p<0.05) more NETs between day 4-6 of life compared to WT controls, suggesting that HTRA1 regulates NET formation through nNIF production. CONCLUSIONS: Placental HTRA1 interacts with AAT to generate a carboxy-terminus cleavage fragment of AAT with identical NET-inhibitory properties to nNIF. Our data strongly indicate that placental HTRA1 generates nNIF in the fetal circulation. We speculate that nNIF participates in the required tolerance to new microbial antigens encountered during the transition to extrauterine life. Disclosures No relevant conflicts of interest to declare.

4077 Background: Human HtrA1 is a member of the HtrA (High temperature requirement) family of serine proteases. Recent reports suggest that htrA1 plays a protective role in varous malignancies due to its tumour suppressive properties. This study was performed to estimate HtrA1 expression as a predictor of the response to chemotherapy of patients with gastric cancer. Methods: HtrA1 was measured immunohistochemically on archival specimens of primary gastric cancer from 51 patients treated consecutively at our institution with a weekly chemotherapy including cisplatin 40 mg/m2, epirubicin 35 mg/m2, 6S-leucovorin 100 mg/m2, 5-fluorouracil 500 mg/m2, with the support of filgrastim 5 μg/Kg from the day 2 to 7 (PELF regimen), or cisplatin 40 mg/m2, epirubicin 35 mg/m2, 6S-leucovorin 100 mg/m2, 5-fluorouracil 500 mg/m2 (PLF regimen). Response to chemotherapy was assessed after 8 weekly treatments according to the WHO criteria. Results: our population consisted of M/F 32/19; median age 64 years (range, 46–79). The prevalent metastatic sites were liver (17 pts), peritoneum (13 pts), lymph nodes (21 pts), locoregional disease (16 pts); 31/16/4 pts had 1/2/3 or more sites of disease. 23 pts had a low expression of HtrA1 (0/1+) versus 28 patients with higher expression (2+). Of the total 51 patients, there were 28 responders: 8 showing complete response (CR) and 20, partial response (PR). Of the 28 responders, 20 were in the higher HtrA1 staining group (2+), while of the 23 non-responders, 15 were in the higher HtrA1 staining group (0/1+). A statistically significant correlation between HtrA1 expression (HtrA1 2+ versus HtrA1 0/1+) and the clinical response was observed (response rate in patients with 2+ and 0/1+: 71.4% versus 34.8%, P < 0.01, respectively). Interestingly, among 16 pts with locoregional disease (stomach, gastric bed, anastomosis), 1/6 pts had HtrA1 1+ expression compared to 8/10 pts with HtrA1 2+ (17% versus 80%, respectively; p = 0.025). Conclusions: The immunohistochemical identification of HtrA1 on the primary gastric cancer prior to chemotherapy may be a useful predictor for choice of potentially responders to a cisplatin-based chemotherapy. No significant financial relationships to disclose.

Cerebral amyloid angiopathy (CAA) is characterized by accumulation of amyloid β (Aβ) in walls of leptomeningeal vessels and cortical capillaries in the brain. The loss of integrity of these vessels caused by cerebrovascular Aβ deposits results in fragile vessels and lobar intracerebral hemorrhages. CAA also manifests with progressive cognitive impairment or transient focal neurological symptoms. Although development of therapeutics for CAA is urgently needed, the pathogenesis of CAA remains to be fully elucidated. In this review, we summarize the epidemiology, pathology, clinical and radiological features, and perspectives for future research directions in CAA therapeutics. Recent advances in mass spectrometric methodology combined with vascular isolation techniques have aided understanding of the cerebrovascular proteome. In this paper, we describe several potential key CAA-associated molecules that have been identified by proteomic analyses (apolipoprotein E, clusterin, SRPX1 (sushi repeat-containing protein X-linked 1), TIMP3 (tissue inhibitor of metalloproteinases 3), and HTRA1 (HtrA serine peptidase 1)), and their pivotal roles in Aβ cytotoxicity, Aβ fibril formation, and vessel wall remodeling. Understanding the interactions between cerebrovascular Aβ deposits and molecules that accumulate with Aβ may lead to discovery of effective CAA therapeutics and to the identification of biomarkers for early diagnosis.

Background: Cerebral autosomal-dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is an autosomal-dominant, inherited, systemic, vascular disorder primarily involving the small arteries. It is characterized by migraine, recurrent ischemic strokes, cognitive decline, and dementia. Mutations in the Notch receptor 3 gene (NOTCH3) and the HtrA serine peptidase 1 gene (HTRA1) are 2 genetic causes for CADASIL. The NOTCH3 gene, located on chromosome 19p13.12, is the most common disease-causing gene in CADASIL. Objective: To investigate genetic causes in 2 unrelated Han-Chinese patients with presentations strongly suggestive of CADASIL. Methods: Exome sequencing was performed on both patients and potential pathogenic mutations were validated by Sanger sequencing. Results: This study reports on 2 unrelated Han-Chinese patients with presentations strongly suggestive of CADASIL, identifying that NOTCH3 mutations were the genetic cause. A common mutation, c.268C>T (p.Arg90Cys), and a novel mutation, c.331G>T (p.Gly111Cys) in the NOTCH3 gene, were detected and confirmed in the patients, respectively, and were predicted to be deleterious based on bioinformation analyses. Conclusions: We identified 2 NOTCH3 mutations as likely genetic causes for CADASIL in these 2 patients. Our findings broaden the mutational spectrum of the NOTCH3 gene accountable for CADASIL. Clinical manifestations supplemented with molecular genetic analyses are critical for accurate diagnosis, the provision of genetic counseling, and the development of therapies for CADASIL.

HtrA which is characterized by the combination of a trypsin-like catalytic domain with at least one C-terminalPDZ domain is a highly conserved family of serine proteases found in a wide range of organisms. However theidentified HtrA family numbers varies among spesies, for example the number of mammalian, Eschericia coli,fruit fly-HtrA family are 4, 3 and 1 gene respectively. One gene is predicted exist in zebrafish. Since no completeinformation available on zebrafish HtrA, in this paper zebrafish HtrA (zHtrA) gene was analyzed. The zHtrA isbelonged to HtrA1 member and predicted encodes 478 amino acids with a signal peptide, a IGF binding domain,a Kazal-type inhibitor domain in the up stream of HtrA-bacterial homolog. At the amino acid sequence the zHtrA1showed the 69%, 69%, 68%, 54% and 54% with the rat HtrA1, mouse HtrA1, human HtrA1, human HtrA3 andmouse HtrA4 respectively. The zHtrA1 is firstly expressed at 60 hpf and mainly in the vertebral rudiments in thetail region.