To see the other types of publications on this topic, follow the link: Mice Mitochondria.
Journal articles on the topic 'Mice Mitochondria'
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the top 50 journal articles for your research on the topic 'Mice Mitochondria.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Browse journal articles on a wide variety of disciplines and organise your bibliography correctly.
1
Rossi, Ann E., Simona Boncompagni, Lan Wei, Feliciano Protasi, and Robert T. Dirksen. "Differential impact of mitochondrial positioning on mitochondrial Ca2+ uptake and Ca2+ spark suppression in skeletal muscle." American Journal of Physiology-Cell Physiology 301, no. 5 (November 2011): C1128—C1139. http://dx.doi.org/10.1152/ajpcell.00194.2011.
Full textAbstract:
Muscle contraction requires ATP and Ca2+ and, thus, is under direct control of mitochondria and the sarcoplasmic reticulum. During postnatal skeletal muscle maturation, the mitochondrial network exhibits a shift from a longitudinal (“longitudinal mitochondria”) to a mostly transversal orientation as a result of a progressive increase in mitochondrial association with Ca2+ release units (CRUs) or triads (“triadic mitochondria”). To determine the physiological implications of this shift in mitochondrial disposition, we used confocal microscopy to monitor activity-dependent changes in myoplasmic (fluo 4) and mitochondrial (rhod 2) Ca2+ in single flexor digitorum brevis (FDB) fibers from 1- to 4-mo-old mice. A robust and sustained Ca2+ accumulation in triadic mitochondria was triggered by repetitive tetanic stimulation (500 ms, 100 Hz, every 2.5 s) in FDB fibers from 4-mo-old mice. Specifically, mitochondrial rhod 2 fluorescence increased 272 ± 39% after a single tetanus and 412 ± 45% after five tetani and decayed slowly over 10 min following the final tetanus. Similar results were observed in fibers expressing mitochondrial pericam, a mitochondrial-targeted ratiometric Ca2+ indicator. Interestingly, sustained mitochondrial Ca2+ uptake following repetitive tetanic stimulation was similar for triadic and longitudinal mitochondria in FDB fibers from 1-mo-old mice, and both mitochondrial populations were found by electron microscopy to be continuous and structurally tethered to the sarcoplasmic reticulum. Conversely, the frequency of osmotic shock-induced Ca2+ sparks per CRU density decreased threefold (from 3.6 ± 0.2 to 1.2 ± 0.1 events·CRU−1·min−1·100 μm−2) during postnatal development in direct linear correspondence ( r2 = 0.95) to an increase in mitochondrion-CRU pairing. Together, these results indicate that mitochondrion-CRU association promotes Ca2+ spark suppression but does not significantly impact mitochondrial Ca2+ uptake.
2
Williams, Jessica A., Hong-Min Ni, Yifeng Ding, and Wen-Xing Ding. "Parkin regulates mitophagy and mitochondrial function to protect against alcohol-induced liver injury and steatosis in mice." American Journal of Physiology-Gastrointestinal and Liver Physiology 309, no. 5 (September 1, 2015): G324—G340. http://dx.doi.org/10.1152/ajpgi.00108.2015.
Full textAbstract:
Alcoholic liver disease claims two million lives per year. We previously reported that autophagy protected against alcohol-induced liver injury and steatosis by removing damaged mitochondria. However, the mechanisms for removal of these mitochondria are unknown. Parkin is an evolutionarily conserved E3 ligase that is recruited to damaged mitochondria to initiate ubiquitination of mitochondrial outer membrane proteins and subsequent mitochondrial degradation by mitophagy. In addition to its role in mitophagy, Parkin has been shown to have other roles in maintaining mitochondrial function. We investigated whether Parkin protected against alcohol-induced liver injury and steatosis using wild-type (WT) and Parkin knockout (KO) mice treated with alcohol by the acute-binge and Gao-binge (chronic plus acute-binge) models. We found that Parkin protected against liver injury in both alcohol models, likely because of Parkin's role in maintaining a population of healthy mitochondria. Alcohol caused greater mitochondrial damage and oxidative stress in Parkin KO livers compared with WT livers. After alcohol treatment, Parkin KO mice had severely swollen and damaged mitochondria that lacked cristae, which were not seen in WT mice. Furthermore, Parkin KO mice had decreased mitophagy, β-oxidation, mitochondrial respiration, and cytochrome c oxidase activity after acute alcohol treatment compared with WT mice. Interestingly, liver mitochondria seemed able to adapt to alcohol treatment, but Parkin KO mouse liver mitochondria had less capacity to adapt to Gao-binge treatment compared with WT mouse liver mitochondria. Overall, our findings indicate that Parkin is an important mediator of protection against alcohol-induced mitochondrial damage, steatosis, and liver injury.
3
King, Adrienne L., Telisha M. Swain, Zhengkuan Mao, Uduak S. Udoh, Claudia R. Oliva, Angela M. Betancourt, Corrine E. Griguer, David R. Crowe, Mathieu Lesort, and Shannon M. Bailey. "Involvement of the mitochondrial permeability transition pore in chronic ethanol-mediated liver injury in mice." American Journal of Physiology-Gastrointestinal and Liver Physiology 306, no. 4 (February 15, 2014): G265—G277. http://dx.doi.org/10.1152/ajpgi.00278.2013.
Full textAbstract:
Chronic ethanol consumption increases sensitivity of the mitochondrial permeability transition (MPT) pore induction in liver. Ca2+ promotes MPT pore opening, and genetic ablation of cyclophilin D (CypD) increases the Ca2+ threshold for the MPT. We used wild-type (WT) and CypD-null (CypD−/−) mice fed a control or an ethanol-containing diet to investigate the role of the MPT in ethanol-mediated liver injury. Ca2+-mediated induction of the MPT and mitochondrial respiration were measured in isolated liver mitochondria. Steatosis was present in WT and CypD−/− mice fed ethanol and accompanied by increased terminal deoxynucleotidyl transferase dUTP-mediated nick-end label-positive nuclei. Autophagy was increased in ethanol-fed WT mice compared with ethanol-fed CypD−/− mice, as reflected by an increase in the ratio of microtubule protein 1 light chain 3B II to microtubule protein 1 light chain 3B I. Higher levels of p62 were measured in CypD−/− than WT mice. Ethanol decreased mitochondrial respiratory control ratios and select complex activities in WT and CypD−/− mice. Ethanol also increased CypD protein in liver of WT mice. Mitochondria from control- and ethanol-fed WT mice were more sensitive to Ca2+-mediated MPT pore induction than mitochondria from their CypD−/− counterparts. Mitochondria from ethanol-fed CypD−/− mice were also more sensitive to Ca2+-induced swelling than mitochondria from control-fed CypD−/− mice but were less sensitive than mitochondria from ethanol-fed WT mice. In summary, CypD deficiency was associated with impaired autophagy and did not prevent ethanol-mediated steatosis. Furthermore, increased MPT sensitivity was observed in mitochondria from ethanol-fed WT and CypD−/− mice. We conclude that chronic ethanol consumption likely lowers the threshold for CypD-regulated and -independent characteristics of the ethanol-mediated MPT pore in liver mitochondria.
4
Saleem, Ayesha, Sobia Iqbal, Yuan Zhang, and David A. Hood. "Effect of p53 on mitochondrial morphology, import, and assembly in skeletal muscle." American Journal of Physiology-Cell Physiology 308, no. 4 (February 15, 2015): C319—C329. http://dx.doi.org/10.1152/ajpcell.00253.2014.
Full textAbstract:
The purpose of this study was to investigate whether p53 regulates mitochondrial function via changes in mitochondrial protein import, complex IV (COX) assembly, or the expression of key proteins involved in mitochondrial dynamics and degradation. Mitochondria from p53 KO mice displayed ultra-structural alterations and were more punctate in appearance. This was accompanied by protein-specific alterations in fission, fusion, and mitophagy-related proteins. However, matrix-destined protein import into subsarcolemmal or intermyofibrillar mitochondria was unaffected in the absence of p53, despite mitochondrial subfraction-specific reductions in Tom20, Tim23, mtHsp70, and mtHsp60 in the knockout (KO) mitochondria. Complex IV activity in isolated mitochondria was also unchanged in KO mice, but two-dimensional blue native-PAGE revealed a reduction in the assembly of complex IV within the IMF fractions from KO mice in tandem with lower levels of the assembly protein Surf1. This observed defect in complex IV assembly may facilitate the previously documented impairment in mitochondrial function in p53 KO mice. We suspect that these morphological and functional impairments in mitochondria drive a decreased reliance on mitochondrial respiration as a means of energy production in skeletal muscle in the absence of p53.
5
Eismann, Thorsten, Nadine Huber, Thomas Shin, Satoshi Kuboki, Elizabeth Galloway, Michael Wyder, Michael J. Edwards, et al. "Peroxiredoxin-6 protects against mitochondrial dysfunction and liver injury during ischemia-reperfusion in mice." American Journal of Physiology-Gastrointestinal and Liver Physiology 296, no. 2 (February 2009): G266—G274. http://dx.doi.org/10.1152/ajpgi.90583.2008.
Full textAbstract:
Hepatic ischemia-reperfusion (I/R) injury is an important complication of liver surgery and transplantation. Mitochondrial function is central to this injury. To examine alterations in mitochondrial function during I/R, we assessed the mitochondrial proteome in C57Bl/6 mice. Proteomic analysis of liver mitochondria revealed 234 proteins with significantly altered expression after I/R. From these, 13 proteins with the greatest expression differences were identified. One of these proteins, peroxiredoxin-6 (Prdx6), has never before been described in mitochondria. In hepatocytes from sham-operated mice, Prdx6 expression was found exclusively in the cytoplasm. After ischemia or I/R, Prdx6 expression disappeared from the cytoplasm and appeared in the mitochondria, suggesting mitochondrial trafficking. To explore the functional role of Prdx6 in hepatic I/R injury, wild-type and Prdx6-knockout mice were subjected to I/R injury. Prdx6-knockout mice had significantly more hepatocellular injury compared with wild-type mice. Interestingly, the increased injury in Prdx6-knockout mice occurred despite reduced inflammation and was associated with increased mitochondrial generation of H2O2 and dysfunction. The mitochondrial dysfunction appeared to be related to complex I of the electron transport chain. These data suggest that hepatocyte Prdx6 traffics to the mitochondria during I/R to limit mitochondrial dysfunction as a protective mechanism against hepatocellular injury.
6
Fokin, Andrej, Rasa Žūkienė, and Aivaras Ratkevičius. "REDUCED CITRATE SYNTHASE ACTIVITY EFFECT ON OXYGEN CONSUMPTION RATES IN ISOLATED MITOCHONDRIA FROM MICE LIVER AND MUSCLES." Baltic Journal of Sport and Health Sciences 2, no. 101 (2016): 26–30. http://dx.doi.org/10.33607/bjshs.v2i101.52.
Full textAbstract:
Background. Liver and skeletal muscles play the major role in metabolism. Mitochondria are of particular importance in functioning of these organs. We tested the hypothesis that reduced citrate synthase (CS) activity could induce improved fatty substrate and carbohydrate oxidation in mitochondria extracted from liver and hind limb muscles of mice. Methods. Eight mice each of 12-week-old control C57B6/J (B6) and congenic B6.A-(rs3676616-D10Utsw1)/ Kjn (B6.A) mice were studied. The mitochondria were isolated by differential centrifugation method followed by assessment of mitochondrial respiration and citrate synthase (CS) activity. Mitochondrial respiration was measured as oxygen consumption with Clark-type oxygen electrode by using polarography system. CS enzyme activity was measured spectrophotometrically. Results. The activity of CS was by ~32% lower for mitochondria for B6.A compared to B6 mice (603.9 ± 135.6 U/g and 894.2 ± 193.2 U/g, respectively). Mitochondrial respiration did not differ significantly between the strains. Conclusions. 30% reduction in citrate synthase activity does not impair mitochondrial respiration.
7
SPEER, Oliver, Nils BÄCK, Tanja BUERKLEN, Dieter BRDICZKA, Alan KORETSKY, Theo WALLIMANN, and Ove ERIKSSON. "Octameric mitochondrial creatine kinase induces and stabilizes contact sites between the inner and outer membrane." Biochemical Journal 385, no. 2 (January 7, 2005): 445–50. http://dx.doi.org/10.1042/bj20040386.
Full textAbstract:
We have investigated the role of the protein ubiquitous mitochondrial creatine kinase (uMtCK) in the formation and stabilization of inner and outer membrane contact sites. Using liver mitochondria isolated from transgenic mice, which, unlike control animals, express uMtCK in the liver, we found that the enzyme was associated with the mitochondrial membranes and, in addition, was located in membrane-coated matrix inclusions. In mitochondria isolated from uMtCK transgenic mice, the number of contact sites increased 3-fold compared with that observed in control mitochondria. Furthermore, uMtCK-containing mitochondria were more resistant to detergent-induced lysis than wild-type mitochondria. We conclude that octameric uMtCK induces the formation of mitochondrial contact sites, leading to membrane cross-linking and to an increased stability of the mitochondrial membrane architecture.
8
Hamilton, James, Tatiana Brustovetsky, Rajesh Khanna, and Nickolay Brustovetsky. "Mutant huntingtin does not cross the mitochondrial outer membrane." Human Molecular Genetics 29, no. 17 (August 21, 2020): 2962–75. http://dx.doi.org/10.1093/hmg/ddaa185.
Full textAbstract:
Abstract Mutant huntingtin (mHTT) is associated with mitochondria, but the exact mitochondrial location of mHTT has not been definitively established. Recently, it was reported that mHTT is present in the intermembrane space and inhibits mitochondrial protein import by interacting with TIM23, a major component of mitochondrial protein import machinery, but evidence for functional ramifications were not provided. We assessed mHTT location using synaptic and nonsynaptic mitochondria isolated from brains of YAC128 mice and subjected to alkali treatment or limited trypsin digestion. Mitochondria were purified either with discontinuous Percoll gradient or with anti-TOM22-conjugated iron microbeads. We also used mitochondria isolated from postmortem brain tissues of unaffected individuals and HD patients. Our results demonstrate that mHTT is located on the cytosolic side of the mitochondrial outer membrane (MOM) but does not cross it. This refutes the hypothesis that mHTT may interact with TIM23 and inhibit mitochondrial protein import. The levels of expression of nuclear-encoded, TIM23-transported mitochondrial proteins ACO2, TUFM, IDH3A, CLPP and mitochondrially encoded and synthesized protein mtCO1 were similar in mitochondria from YAC128 mice and their wild-type littermates as well as in mitochondria from postmortem brain tissues of unaffected individuals and HD patients, supporting the lack of deficit in mitochondrial protein import. Regardless of purification technique, mitochondria from YAC128 and WT mice had similar respiratory activities and mitochondrial membrane potentials. Thus, our data argue against mHTT crossing the MOM and entering into the mitochondrial intermembrane space, making it highly unlikely that mHTT interacts with TIM23 and inhibits protein import in intact mitochondria.
9
Martin, George M., and Lawrence A. Loeb. "Mice and mitochondria." Nature 429, no. 6990 (May 2004): 357–59. http://dx.doi.org/10.1038/429357a.
Full text
10
Kuznetsov, Andrey V., Oleg Mayboroda, Dagmar Kunz, Kirstin Winkler, Walter Schubert, and Wolfram S. Kunz. "Functional Imaging of Mitochondria in Saponin-permeabilized Mice Muscle Fibers." Journal of Cell Biology 140, no. 5 (March 9, 1998): 1091–99. http://dx.doi.org/10.1083/jcb.140.5.1091.
Full textAbstract:
Confocal laser-scanning and digital fluorescence imaging microscopy were used to quantify the mitochondrial autofluorescence changes of NAD(P)H and flavoproteins in unfixed saponin-permeabilized myofibers from mice quadriceps muscle tissue. Addition of mitochondrial substrates, ADP, or cyanide led to redox state changes of the mitochondrial NAD system. These changes were detected by ratio imaging of the autofluorescence intensities of fluorescent flavoproteins and NAD(P)H, showing inverse fluorescence behavior. The flavoprotein signal was colocalized with the potentiometric mitochondria-specific dye dimethylaminostyryl pyridyl methyl iodide (DASPMI), or with MitoTracker™ Green FM, a constitutive marker for mitochondria. Within individual myofibers we detected topological mitochondrial subsets with distinct flavoprotein autofluorescence levels, equally responding to induced rate changes of the oxidative phosphorylation. The flavoprotein autofluorescence levels of these subsets differed by a factor of four. This heterogeneity was substantiated by flow-cytometric analysis of flavoprotein and DASPMI fluorescence changes of individual mitochondria isolated from mice skeletal muscle. Our data provide direct evidence that mitochondria in single myofibers are distinct subsets at the level of an intrinsic fluorescent marker of the mitochondrial NAD–redox system. Under the present experimental conditions these subsets show similar functional responses.
11
Sayen, M. R., Åsa B. Gustafsson, Mark A. Sussman, Jeffery D. Molkentin, and Roberta A. Gottlieb. "Calcineurin transgenic mice have mitochondrial dysfunction and elevated superoxide production." American Journal of Physiology-Cell Physiology 284, no. 2 (February 1, 2003): C562—C570. http://dx.doi.org/10.1152/ajpcell.00336.2002.
Full textAbstract:
Introduction of the constitutively active calcineurin gene into neonatal rat cardiomyocytes by adenovirus resulted in decreased mitochondrial membrane potential ( P < 0.05). Infection of H9c2 cells with calcineurin adenovirus resulted in increased superoxide production ( P < 0.001). Transgenic mice with cardiac-specific expression of a constitutively active calcineurin cDNA (CalTG mice) exhibit a two- to threefold increase in heart size that progresses to heart failure. We prepared mitochondria enriched for the subsarcolemmal population from the hearts of CalTG mice and transgene negative littermates (control). Intact, well-coupled mitochondria prepared from one to two mouse hearts at a time yielded sufficient material for functional studies. Mitochondrial oxygen consumption was measured with a Clark-type oxygen electrode with substrates for mitochondrial complex II (succinate) and complex IV [tetramethylpentadecane (TMPD)/ascorbate]. CalTG mice exhibited a maximal rate of electron transfer in heart mitochondria that was reduced by ∼50% ( P < 0.002) without a loss of respiratory control. Mitochondrial respiration was unaffected in tropomodulin-overexpressing transgenic mice, another model of cardiomyopathy. Western blotting for mitochondrial electron transfer subunits from mitochondria of CalTG mice revealed a 20–30% reduction in subunit 3 of complex I (ND3) and subunits I and IV of cytochrome oxidase (CO-I, CO-IV) when normalized to total mitochondrial protein or to the adenine nucleotide transporter (ANT) and compared with littermate controls ( P < 0.002). Impaired mitochondrial electron transport was associated with high levels of superoxide production in the CalTG mice. Taken together, these data indicate that calcineurin signaling affects mitochondrial energetics and superoxide production. The excessive production of superoxide may contribute to the development of cardiac failure.
12
Dubinin, Mikhail V., Vlada S. Starinets, Eugeny Yu Talanov, Irina B. Mikheeva, Natalia V. Belosludtseva, Dmitriy A. Serov, Kirill S. Tenkov, Evgeniya V. Belosludtseva, and Konstantin N. Belosludtsev. "Effect of the Non-Immunosuppressive MPT Pore Inhibitor Alisporivir on the Functioning of Heart Mitochondria in Dystrophin-Deficient mdx Mice." Biomedicines 9, no. 9 (September 16, 2021): 1232. http://dx.doi.org/10.3390/biomedicines9091232.
Full textAbstract:
Supporting mitochondrial function is one of the therapeutic strategies that improve the functioning of skeletal muscle in Duchenne muscular dystrophy (DMD). In this work, we studied the effect of a non-immunosuppressive inhibitor of mitochondrial permeability transition pore (MPTP) alisporivir (5 mg/kg/day), reducing the intensity of the necrotic process and inflammation in skeletal muscles on the cardiac phenotype of dystrophin-deficient mdx mice. We found that the heart mitochondria of mdx mice show an increase in the intensity of oxidative phosphorylation and an increase in the resistance of organelles to the MPT pore opening. Alisporivir had no significant effect on the hyperfunctionalization of the heart mitochondria of mdx mice, and the state of the heart mitochondria of wild-type animals did not affect the dynamics of organelles but significantly suppressed mitochondrial biogenesis and reduced the amount of mtDNA in the heart muscle. Moreover, alisporivir suppressed mitochondrial biogenesis in the heart of wild-type mice. Alisporivir treatment resulted in a decrease in heart weight in mdx mice, which was associated with a significant modification of the transmission of excitation in the heart. The latter was also noted in the case of WT mice treated with alisporivir. The paper discusses the prospects for using alisporivir to correct the function of heart mitochondria in DMD.
13
Carpenter, T. O., and T. Shiratori. "Renal 25-hydroxyvitamin D-1 alpha-hydroxylase activity and mitochondrial phosphate transport in Hyp mice." American Journal of Physiology-Endocrinology and Metabolism 259, no. 6 (December 1, 1990): E814—E821. http://dx.doi.org/10.1152/ajpendo.1990.259.6.e814.
Full textAbstract:
The Hyp mouse is a homologue of the X chromosome-linked human disease, familial hypophosphatemic rickets (FHR). In FHR, reduced renal tubular brush-border membrane transport of phosphate results in hypophosphatemia and rickets. Both humans with FHR and Hyp mice have abnormal regulation of 25-hydroxyvitamin D-1 alpha-hydroxylase (1 alpha-hydroxylase), a mitochondrial enzyme found in proximal renal tubular cell epithelia, the apparent site of defective brush-border membrane phosphate transport. No common pathophysiology for these defects has been demonstrated. We hypothesized that phosphate transport may be present in renal mitochondria from Hyp mice and that its regulation may be deranged in parallel with the mitochondrial 1 alpha-hydroxylase. Using inhibitor-stop techniques described for measurement of phosphate transport in liver mitochondria, we examined mitochondria in normal and Hyp mouse kidney and found them to be comparable. We performed manipulations known to alter 1 alpha-hydroxylase differentially in normal and Hyp mice, i.e., phosphorus deprivation and phosphorus loading, and found no effect on mitochondrial phosphate transport. We also subjected Hyp and normal mice to calcium and vitamin D deprivation; this maneuver resulted in no significant changes in mitochondrial phosphate transport in Hyp or normal mice but confirmed the earlier observation that 1 alpha-hydroxylase activity is stimulated to a greater degree in normal mice than Hyp mice after this diet. Furthermore, administration of 1,25-hydroxyvitamin D3 depresses 1 alpha-hydroxylase activity in mitochondria from both normal and Hyp mice but has no effect on mitochondrial phosphate transport. We conclude that the mechanism of abnormal vitamin D metabolism in Hyp mice is not related to a primary defect in renal mitochondrial phosphate transport.
14
Nakamura, Yoshihiko, Eng H. Lo, and Kazuhide Hayakawa. "Placental Mitochondria Therapy for Cerebral Ischemia-Reperfusion Injury in Mice." Stroke 51, no. 10 (October 2020): 3142–46. http://dx.doi.org/10.1161/strokeaha.120.030152.
Full textAbstract:
Background and Purpose: There is an urgent need to develop adjunct therapies that can be added onto reperfusion for acute ischemic stroke. Recently, mitochondrial transplantation has emerged as a promising therapeutic approach for boosting brain tissue protection. In this proof-of-concept study, we investigate the feasibility of using placenta as a source for mitochondrial transplantation in a mouse model of transient focal cerebral ischemia-reperfusion. Methods: Mitochondria-enriched fractions were isolated from cryopreserved mouse placenta. Mitochondrial purity and JC1 membrane potentials were assessed by flow cytometry. Adenosine triphosphate and mitochondrial proteins were measured by luminescence intensity and western blot, respectively. Therapeutic efficacy of mitochondrial fractions was assessed in a mouse model of transient focal cerebral ischemia-reperfusion. Results: Flow cytometry analysis demonstrated that about 87% of placental mitochondria were viable and maintained JC1 membrane potentials after isolation. Placental mitochondrial fractions contained adenosine triphosphate equivalent to mitochondrial fractions isolated from skeletal muscle and brown fat tissue. Normalized mitochondrial antioxidant enzymes (glutathione reductase, MnSOD [manganese superoxide dismutase]) and HSP70 (heat shock protein 70) were highly preserved in placental mitochondrial fractions. Treatment with placental mitochondrial fractions immediately after reperfusion significantly decreased infarction after focal cerebral ischemia in mice. Conclusions: Cryopreserved placenta can be a feasible source for viable mitochondrial isolation. Transplantation with placental mitochondria may amplify beneficial effects of reperfusion in stroke.
15
Rodriguez, M. I., G. Escames, L. C. López, J. A. García, F. Ortiz, A. López, and D. Acuña-Castroviejo. "Melatonin administration prevents cardiac and diaphragmatic mitochondrial oxidative damage in senescence-accelerated mice." Journal of Endocrinology 194, no. 3 (September 2007): 637–43. http://dx.doi.org/10.1677/joe-07-0260.
Full textAbstract:
Cardiac and diaphragmatic mitochondria from male SAMP8 (senescent) and SAMR1 (resistant) mice of 5 or 10 months of age were studied. Levels of lipid peroxidation (LPO), glutathione (GSH), GSH disulfide (GSSG), and GSH peroxidase and GSH reductase (GRd) activities were measured. In addition, the effect of chronic treatment with the antioxidant melatonin from 1 to 10 months of age was evaluated. Cardiac and diaphragmatic mitochondria show an age-dependent increase in LPO levels and a reduction in GSH:GSSG ratios. Chronic treatment with melatonin counteracted the age-dependent LPO increase and GSH:GSSG ratio reduction in these mitochondria. Melatonin also increased GRd activity, an effect that may account for the maintenance of the mitochondrial GSH pool. Total mitochondrial content of GSH increased after melatonin treatment. In general, the effects of age and melatonin treatment were similar in senescence-resistant mice (SAMR1) and SAMP8 cardiac and diaphragmatic mitochondria, suggesting that these mice strains display similar mitochondrial oxidative damage at the age of 10 months. The results also support the efficacy of long-term melatonin treatment in preventing the age-dependent mitochondrial oxidative stress.
16
Munusamy, Shankar, Jussara M. do Carmo, Jonathan P. Hosler, and John E. Hall. "Obesity-induced changes in kidney mitochondria and endoplasmic reticulum in the presence or absence of leptin." American Journal of Physiology-Renal Physiology 309, no. 8 (October 15, 2015): F731—F743. http://dx.doi.org/10.1152/ajprenal.00188.2015.
Full textAbstract:
We investigated obesity-induced changes in kidney lipid accumulation, mitochondrial function, and endoplasmic reticulum (ER) stress in the absence of hypertension, and the potential role of leptin in modulating these changes. We compared two normotensive genetic mouse models of obesity, leptin-deficient ob/ob mice and hyperleptinemic melanocortin-4 receptor-deficient mice (LoxTB MC4R−/−), with their respective lean controls. Compared with controls, ob/ob and LoxTB MC4R−/− mice exhibit significant albuminuria, increased creatinine clearance, and high renal triglyceride content. Renal ATP levels were decreased in both obesity models, and mitochondria isolated from both models showed alterations that would lower mitochondrial ATP production. Mitochondria from hyperleptinemic LoxTB MC4R−/− mice kidneys respired NADH-generating substrates (including palmitate) at lower rates due to an apparent decrease in complex I activity, and these mitochondria showed oxidative damage. Kidney mitochondria of leptin-deficient ob/ob mice showed normal rates of respiration with no evidence of oxidative damage, but electron transfer was partially uncoupled from ATP synthesis. A fourfold induction of C/EBP homologous protein (CHOP) expression indicated induction of ER stress in kidneys of hyperleptinemic LoxTB MC4R−/− mice. In contrast, ER stress was not induced in kidneys of leptin-deficient ob/ob mice. Our findings show that obesity, in the absence of hypertension, is associated with renal dysfunction in mice but not with major renal injury. Alterations to mitochondria that lower cellular ATP levels may be involved in obesity-induced renal injury. The type and severity of mitochondrial and ER dysfunction differs depending upon the presence or absence of leptin.
17
De Gaetano, Anna, Lara Gibellini, Elena Bianchini, Rebecca Borella, Sara De Biasi, Milena Nasi, Federica Boraldi, Andrea Cossarizza, and Marcello Pinti. "Impaired Mitochondrial Morphology and Functionality in Lonp1wt/− Mice." Journal of Clinical Medicine 9, no. 6 (June 8, 2020): 1783. http://dx.doi.org/10.3390/jcm9061783.
Full textAbstract:
LONP1 is a nuclear-encoded mitochondrial protease crucial for organelle homeostasis; mutations of LONP1 have been associated with Cerebral, Ocular, Dental, Auricular, and Skeletal anomalies (CODAS) syndrome. To clarify the role of LONP1 in vivo, we generated a mouse model in which Lonp1 was ablated. The homozygous Lonp−/− mouse was not vital, while the heterozygous Lonp1wt/− showed similar growth rate, weight, length, life-span and histologic features as wild type. Conversely, ultrastructural analysis of heterozygous enterocytes evidenced profound morphological alterations of mitochondria, which appeared increased in number, swollen and larger, with a lower complexity. Embryonic fibroblasts (MEFs) from Lonp1wt/− mice showed a reduced expression of Lonp1 and Tfam, whose expression is regulated by LONP1. Mitochondrial DNA was also reduced, and mitochondria were swollen and larger, albeit at a lesser extent than enterocytes, with a perinuclear distribution. From the functional point of view, mitochondria from heterozygous MEF showed a lower oxygen consumption rate in basal conditions, either in the presence of glucose or galactose, and a reduced expression of mitochondrial complexes than wild type. In conclusion, the presence of one functional copy of the Lonp1 gene leads to impairment of mitochondrial ultrastructure and functions in vivo.
18
Dubinin, Mikhail V., Eugeny Yu Talanov, Kirill S. Tenkov, Vlada S. Starinets, Natalia V. Belosludtseva, and Konstantin N. Belosludtsev. "The Effect of Deflazacort Treatment on the Functioning of Skeletal Muscle Mitochondria in Duchenne Muscular Dystrophy." International Journal of Molecular Sciences 21, no. 22 (November 19, 2020): 8763. http://dx.doi.org/10.3390/ijms21228763.
Full textAbstract:
Duchenne muscular dystrophy (DMD) is a severe hereditary disease caused by a lack of dystrophin, a protein essential for myocyte integrity. Mitochondrial dysfunction is reportedly responsible for DMD. This study examines the effect of glucocorticoid deflazacort on the functioning of the skeletal-muscle mitochondria of dystrophin-deficient mdx mice and WT animals. Deflazacort administration was found to improve mitochondrial respiration of mdx mice due to an increase in the level of ETC complexes (complexes III and IV and ATP synthase), which may contribute to the normalization of ATP levels in the skeletal muscle of mdx animals. Deflazacort treatment improved the rate of Ca2+ uniport in the skeletal muscle mitochondria of mdx mice, presumably by affecting the subunit composition of the calcium uniporter of organelles. At the same time, deflazacort was found to reduce the resistance of skeletal mitochondria to MPT pore opening, which may be associated with a change in the level of ANT2 and CypD. In this case, deflazacort also affected the mitochondria of WT mice. The paper discusses the mechanisms underlying the effect of deflazacort on the functioning of mitochondria and contributing to the improvement of the muscular function of mdx mice.
19
Ronchi, Juliana A., Barbara Henning, Felipe G. Ravagnani, Tiago R. Figueira, Roger F. Castilho, Sergio F. dos Reis, and Anibal E. Vercesi. "Increased Susceptibility ofGracilinanus microtarsusLiver Mitochondria to Ca2+-Induced Permeability Transition Is Associated with a More Oxidized State of NAD(P)." Oxidative Medicine and Cellular Longevity 2015 (2015): 1–10. http://dx.doi.org/10.1155/2015/940627.
Full textAbstract:
In addition to be the cell’s powerhouse, mitochondria also contain a cell death machinery that includes highly regulated processes such as the membrane permeability transition pore (PTP) and reactive oxygen species (ROS) production. In this context, the results presented here provide evidence that liver mitochondria isolated fromGracilinanus microtarsus, a small and short life span (one year) marsupial, when compared to mice, are much more susceptible to PTP opening in association with a poor NADPH dependent antioxidant capacity. Liver mitochondria isolated from the marsupial are well coupled and take upCa2+but exhibited a much lowerCa2+retention capacity than mouse mitochondria. Although the known PTP inhibitors cyclosporin A, ADP, and ATP significantly increased the marsupial mitochondria capacity to retainCa2+, their effects were much larger in mice than in marsupial mitochondria. Both fluorescence and HPLC analysis of mitochondrial nicotinamide nucleotides showed that both content and state of reduction (mainly of NADPH) were lower in the marsupial mitochondria than in mice mitochondria despite the similarity in the activity of the glutathione peroxidase/reductase system. Overall, these data suggest that PTP opening is an important event in processes ofCa2+signalling to cell death mediated by mitochondrial redox imbalance inG. microtarsus.
20
Takihara, Yuji, Masaru Inatani, Kei Eto, Toshihiro Inoue, Alexander Kreymerman, Seiji Miyake, Shinji Ueno, et al. "In vivo imaging of axonal transport of mitochondria in the diseased and aged mammalian CNS." Proceedings of the National Academy of Sciences 112, no. 33 (August 3, 2015): 10515–20. http://dx.doi.org/10.1073/pnas.1509879112.
Full textAbstract:
The lack of intravital imaging of axonal transport of mitochondria in the mammalian CNS precludes characterization of the dynamics of axonal transport of mitochondria in the diseased and aged mammalian CNS. Glaucoma, the most common neurodegenerative eye disease, is characterized by axon degeneration and the death of retinal ganglion cells (RGCs) and by an age-related increase in incidence. RGC death is hypothesized to result from disturbances in axonal transport and in mitochondrial function. Here we report minimally invasive intravital multiphoton imaging of anesthetized mouse RGCs through the sclera that provides sequential time-lapse images of mitochondria transported in a single axon with submicrometer resolution. Unlike findings from explants, we show that the axonal transport of mitochondria is highly dynamic in the mammalian CNS in vivo under physiological conditions. Furthermore, in the early stage of glaucoma modeled in adult (4-mo-old) mice, the number of transported mitochondria decreases before RGC death, although transport does not shorten. However, with increasing age up to 23–25 mo, mitochondrial transport (duration, distance, and duty cycle) shortens. In axons, mitochondria-free regions increase and lengths of transported mitochondria decrease with aging, although totally organized transport patterns are preserved in old (23- to 25-mo-old) mice. Moreover, axonal transport of mitochondria is more vulnerable to glaucomatous insults in old mice than in adult mice. These mitochondrial changes with aging may underlie the age-related increase in glaucoma incidence. Our method is useful for characterizing the dynamics of axonal transport of mitochondria and may be applied to other submicrometer structures in the diseased and aged mammalian CNS in vivo.
21
Bézaire, Véronic, Wolfgang Hofmann, John K. G. Kramer, Leslie P. Kozak, and Mary-Ellen Harper. "Effects of fasting on muscle mitochondrial energetics and fatty acid metabolism in Ucp3(−/−) and wild-type mice." American Journal of Physiology-Endocrinology and Metabolism 281, no. 5 (November 1, 2001): E975—E982. http://dx.doi.org/10.1152/ajpendo.2001.281.5.e975.
Full textAbstract:
Uncoupling protein-3 (UCP3) is a mitochondrial carrier protein of as yet undefined physiological function. To elucidate characteristics of its function, we studied the effects of fasting on resting metabolic rate, respiratory quotient, muscle Ucp3expression, and mitochondrial proton leak in wild-type and Ucp3(−/−) mice. Also analyzed were the fatty acid compositions of skeletal muscle mitochondria in fed and fasted Ucp3(−/−) and wild-type mice. In wild-type mice, fasting caused significant increases in Ucp3 (4-fold) and Ucp2 (2-fold) mRNA but did not significantly affect mitochondrial proton leak. State 4 oxygen consumption was not affected by fasting in either of the two groups. However, protonmotive force was consistently higher in mitochondria of Ucp3(−/−) animals ( P = 0.03), and fasting further augmented protonmotive force in Ucp3(−/−) mice; there was no effect in wild-type mitochondria. Resting metabolic rates decreased with fasting in both groups. Ucp3(−/−) mice had higher respiratory quotients than wild-type mice in fed resting states, indicating impaired fatty acid oxidation. Altogether, results show that the fasting-induced increases in Ucp2 and Ucp3 do not correlate with increased mitochondrial proton leak but support a role for UCP3 in fatty acid metabolism.
22
Holloway, Graham P., Swati S. Jain, Veronic Bezaire, Xiao Xia Han, Jan F. C. Glatz, Joost J. F. P. Luiken, Mary-Ellen Harper, and Arend Bonen. "FAT/CD36-null mice reveal that mitochondrial FAT/CD36 is required to upregulate mitochondrial fatty acid oxidation in contracting muscle." American Journal of Physiology-Regulatory, Integrative and Comparative Physiology 297, no. 4 (October 2009): R960—R967. http://dx.doi.org/10.1152/ajpregu.91021.2008.
Full textAbstract:
The plasma membrane fatty acid transport protein FAT/CD36 is also present at the mitochondria, where it may contribute to the regulation of fatty acid oxidation, although this has been challenged. Therefore, we have compared enzyme activities and rates of mitochondrial palmitate oxidation in muscles of wild-type (WT) and FAT/CD36 knockout (KO) mice, at rest and after muscle contraction. In WT and KO mice, carnitine palmitoyltransferase-I, citrate synthase, and β-hydroxyacyl-CoA dehydrogenase activities did not differ in subsarcolemmal (SS) and intermyofibrillar (IMF) mitochondria of WT and FAT/CD36 KO mice. Basal palmitate oxidation rates were lower ( P < 0.05) in KO mice (SS −18%; IMF −13%). Muscle contraction increased fatty acid oxidation (+18%) and mitochondrial FAT/CD36 protein (+16%) in WT IMF but not in WT SS, or in either mitochondrial subpopulation in KO mice. This revealed that the difference in IMF mitochondrial fatty acid oxidation between WT and KO mice can be increased ∼2.5-fold from 13% under basal conditions to 35% during muscle contraction. The FAT/CD36 inhibitor sulfo- N-succinimidyl oleate (SSO), inhibited palmitate transport across the plasma membrane in WT, but not in KO mice. In contrast, SSO bound to mitochondrial membranes and reduced palmitate oxidation rates to a similar extent in both WT and KO mitochondria (∼80%; P < 0.05). In addition, SSO reduced state III respiration with succinate as a substrate, without altering mitochondrial coupling (P/O ratios). Thus, while SSO inhibits FAT/CD36-mediated palmitate transport at the plasma membrane, SSO has undefined effects on mitochondria. Nevertheless, the KO animals reveal that FAT/CD36 contributes to the regulation of mitochondrial fatty acid oxidation, which is especially important for meeting the increased metabolic demands during muscle contraction.
23
Faustini, Gaia, Elena Marchesan, Laura Zonta, Federica Bono, Emanuela Bottani, Francesca Longhena, Elena Ziviani, Alessandra Valerio, and Arianna Bellucci. "Alpha-Synuclein Preserves Mitochondrial Fusion and Function in Neuronal Cells." Oxidative Medicine and Cellular Longevity 2019 (November 23, 2019): 1–11. http://dx.doi.org/10.1155/2019/4246350.
Full textAbstract:
Dysregulations of mitochondria with alterations in trafficking and morphology of these organelles have been related to Parkinson’s disease (PD), a neurodegenerative disorder characterized by brain accumulation of Lewy bodies (LB), intraneuronal inclusions mainly composed of α-synuclein (α-syn) fibrils. Experimental evidence supports that α-syn pathological aggregation can negatively impinge on mitochondrial functions suggesting that this protein may be crucially involved in the control of mitochondrial homeostasis. The aim of this study was to assay this hypothesis by analyzing mitochondrial function and morphology in primary cortical neurons from C57BL/6JOlaHsd α-syn null and C57BL/6J wild-type (wt) mice. Primary cortical neurons from mice lacking α-syn showed decreased respiration capacity measured with a Seahorse XFe24 Extracellular Flux Analyzer. In addition, morphological Airyscan superresolution microscopy showed the presence of fragmented mitochondria while real-time PCR and western blot confirmed altered expression of proteins involved in mitochondrial shape modifications in the primary cortical neurons of α-syn null mice. Transmission electron microscopy (TEM) studies showed that α-syn null neurons exhibited impaired mitochondria-endoplasmic reticulum (ER) physical interaction. Specifically, we identified a decreased number of mitochondria-ER contacts (MERCs) paralleled by a significant increase in ER-mitochondria distance (i.e., MERC length). These findings support that α-syn physiologically preserves mitochondrial functions and homeostasis. Studying α-syn/mitochondria interplay in health and disease is thus pivotal for understanding their involvement in PD and other LB disorders.
24
Desautels, M. "Mitochondrial thermogenin content is unchanged during atrophy of BAT of fasting mice." American Journal of Physiology-Endocrinology and Metabolism 249, no. 1 (July 1, 1985): E99—E106. http://dx.doi.org/10.1152/ajpendo.1985.249.1.e99.
Full textAbstract:
The objectives of this study were to evaluate the rate at which brown adipose tissue (BAT) from mice atrophies when its thermogenic activity is suppressed during fasting or exposure to a thermoneutral environment (33 degrees C) and whether such atrophy is accompanied by loss from BAT mitochondria of "thermogenin," the GDP binding protein associated with the calorigenic proton conductance pathway. Atrophy of mouse BAT was characterized by rapid loss of protein but unchanged tissue DNA content. The rate of protein loss varied from 2 to 6 mg protein/day depending on the environmental and feeding status of the mice. In synchrony with tissue protein loss, there was a marked reduction in the tissue content of mitochondrial proteins and of thermogenin, measured by immunoassay. However, the concentration of thermogenin in isolated mitochondria was unchanged by fasting or exposure of the mice to 33 degrees C for 48 h. By contrast, marked reduction in [3H]GDP binding to isolated mitochondria were observed after exposure of the mice to 33 degrees C. Mice acclimated at 4 but not those acclimated at 21 degrees C showed reduction in GDP binding to isolated mitochondria during fasting. These results clearly indicate that changes in purine nucleotide binding to isolated mitochondria can occur in the absence of changes in the mitochondrial concentration of thermogenin. Thus rapid decrease in BAT thermogenic capacity (e.g., during fasting or 33 degrees C exposure) appears dependent on extensive loss of tissue protein, probably whole mitochondria, rather than rapid and selective removal of thermogenin from the mitochondria.
25
Chow, Lisa S., Laura J. Greenlund, Yan W. Asmann, Kevin R. Short, Shelly K. McCrady, James A. Levine, and K. Sreekumaran Nair. "Impact of endurance training on murine spontaneous activity, muscle mitochondrial DNA abundance, gene transcripts, and function." Journal of Applied Physiology 102, no. 3 (March 2007): 1078–89. http://dx.doi.org/10.1152/japplphysiol.00791.2006.
Full textAbstract:
We hypothesized that enhanced skeletal muscle mitochondrial function following aerobic exercise training is related to an increase in mitochondrial transcription factors, DNA abundance [mitochondrial DNA (mtDNA)], and mitochondria-related gene transcript levels, as well as spontaneous physical activity (SPA) levels. We report the effects of daily treadmill training on 12-wk-old FVB mice for 5 days/wk over 8 wk at 80% peak O2 consumption and studied the training effect on changes in body composition, glucose tolerance, muscle mtDNA muscle, mitochondria-related gene transcripts, in vitro muscle mitochondrial ATP production capacity (MATPC), and SPA levels. Compared with the untrained mice, the trained mice had higher peak O2 consumption (+18%; P < 0.001), lower percentage of abdominal (−25.4%; P < 0.02) and body fat (−19.5%; P < 0.01), improved glucose tolerance ( P < 0.04), and higher muscle mitochondrial enzyme activity (+19.5–43.8%; P < 0.04) and MATPC (+28.9 to +32.4%; P < 0.01). Gene array analysis showed significant differences in mRNAs of mitochondria-related ontology groups between the trained and untrained mice. Training also increased muscle mtDNA (+88.4 to +110%; P < 0.05), peroxisome proliferative-activated receptor-γ coactivator-1α protein (+99.5%; P < 0.04), and mitochondrial transcription factor A mRNA levels (+21.7%; P < 0.004) levels. SPA levels were higher in trained mice ( P = 0.056, two-sided t-test) and significantly correlated with two separate substrate-based measurements of MATPC ( P < 0.02). In conclusion, aerobic exercise training enhances muscle mitochondrial transcription factors, mtDNA abundance, mitochondria-related gene transcript levels, and mitochondrial function, and this enhancement in mitochondrial function occurs in association with increased SPA.
26
BRAND, Martin D., Reinald PAMPLONA, Manuel PORTERO-OTÍN, Jesús R. REQUENA, Stephen J. ROEBUCK, Julie A. BUCKINGHAM, John C. CLAPHAM, and Susana CADENAS. "Oxidative damage and phospholipid fatty acyl composition in skeletal muscle mitochondria from mice underexpressing or overexpressing uncoupling protein 3." Biochemical Journal 368, no. 2 (December 1, 2002): 597–603. http://dx.doi.org/10.1042/bj20021077.
Full textAbstract:
Five markers of different kinds of oxidative damage to proteins [glutamic semialdehyde, aminoadipic semialdehyde, N∊-(carboxymethyl)lysine, N∊-(carboxyethyl)lysine and N∊-(malondialdehyde)lysine] and phospholipid fatty acyl composition were identified and measured in skeletal muscle mitochondria isolated from mice genetically engineered to underexpress or overexpress uncoupling protein 3 (UCP3). Mitochondria from UCP3-underexpressing mice had significantly higher levels of oxidative damage than wild-type controls, suggesting that UCP3 functions in vivo as part of the antioxidant defences of the cell, but mitochondria from UCP3-overexpressing mice had unaltered oxidative damage, suggesting that mild uncoupling in vivo beyond the normal basal uncoupling provides little protection against oxidative stress. Mitochondria from UCP3-underexpressing mice showed little change, but mitochondria from UCP3-overexpressing mice showed marked changes in mitochondrial phospholipid fatty acyl composition. These changes were very similar to those previously found to correlate with basal proton conductance in mitochondria from a range of species and treatments, suggesting that high protein expression, or some secondary result of uncoupling, may cause the observed correlation between basal proton conductance and phospholipid fatty acyl composition.
27
Liu, Wenli, Yueqin Liu, Ruihong Wang, Cuiling Li, Chuxia Deng, and Griffin P. Rodgers. "Olfactomedin 4 Is Essential for Superoxide Production and Sensitizes Oxidative Stress-Induced Apoptosis in Neutrophils." Blood 114, no. 22 (November 20, 2009): 1356. http://dx.doi.org/10.1182/blood.v114.22.1356.1356.
Full textAbstract:
Abstract Abstract 1356 Poster Board I-378 Introduction Olfactomedin 4 (OLFM4), also called hGC-1, GW112 and pDP4, was first identified and specifically expressed in hematopoietic myeloid cells. OLFM4 expression in myeloid cells is regulated by transcription factors, PU1 and NF-κB. It has significant homology in its C-terminal domain with other olfactomedin-related proteins. OLFM4 encodes a 510 amino acid N-linked glycoprotein. The exact biological function of OLFM4, especially in neutrophils, is currently undefined. To characterize the in vivo function of OLFM4, we generated OLFM4 deficient mice (OLFM4-/-) and investigated its potential role in neutrophil functioins. Results 1) In this study, we showed that OLFM4 is a secreted glycoprotein and is also localized in the mitochondria, cytoplasm and cell membrane fractions of neutrophils. We demonstrated that OLFM4 interacts with GRIM-19 (Genes associated with Retinoid-IFN-induced Mortality-19), an apoptosis related protein, in the neutrophil mitochondria using co-immuoprecipitation assay. GRIM-19 is a subunit of complex I of mitochondrial respiratory chain and is essential for maintenance of mitochondrial membrane potential. Our result suggests that OLFM4 appears to be a novel component of complex I of mitochondrial respiratory chain and may be involved in regulation of mitochondrial membrane potential. 2) Mice heterozygous (OLFM4+/-) and homozygous (OLFM4-/-) for the null mutation in OLFM4 appeared to have normal development, fertility, and viability relative to wild-type (WT) mice. Whole blood analysis, differential leukocyte counts, blood chemistry and bone marrow smears were normal in OLFM4-/- mice, suggesting that OLFM4 is not essential for normal development and hematopoiesis in mice. 3) In response to LPS, fMLP and E.coli bacteria challenge, neutrophils from OLFM4-/- mice showed significantly reduced superoxide (O2−) and hydrogen peroxide (H2O2) production compared with WT mice. These results suggest that OLFM4 is an essential component to mediate O2− and H2O2 production in the neutrophil mitochondria under inflammation stimuli. 4) Exogenous H2O2 induced neutrophil apoptosis in a time and dose dependent manner in WT mice, but this induction of apoptosis was significantly reduced in OLFM4-/- mice. This result suggests that OLFM4 sensitizes and mediates H2O2-induced apoptosis in neutrophils. 5) Furthermore, we demonstrated that H2O2-stimulated mitochondrial membrane permeability reduction and caspase-3 and caspase-9 activation were inhibited in the neutrophils of OLFM4-/- mice. This result confirmed our hypothesis that OLFM4 may be involved in maintenance of mitochondrial membrane potential and suggests that OLFM4 may have opposite role as GRIM-19. 6) Moreover, Bax association with mitochondria and the cytoplasmic translocation of Omi/HtrA2 and Smac/DIABLO in response to H2O2 were inhibited in the neutrophils of OLFM4-/- mice. Conclusion Our results suggest: 1) OLFM4 has multiple subcellular localizations including mitochondria, cytoplasm, and cell membrane in neutrophils. The interaction of OLFM4 with GRIM-19 in the mitochondria suggests that OLFM4 is novel component of complex I of mitochondrial respiratory chain in the mitochondria of neutrophils, 2) OLFM4 is a novel mitochondrial molecule that is essential for O2− and H2O2 production in the neutrophils in the presence of inflammation stimuli, 3) Loss of OLFM4 in neutrophils does not trigger spontaneous apoptosis. However, OLFM4 sensitizes oxidative stress-induced apoptosis in mouse neutrophils. OLFM4 is involved in the regulation of mitochondria membrane potential and sensitizes cytoplasmic translocation of Omi/HtrA2 and Smac/DIABLO and caspases-3 and caspase-9 mediated apoptosis in the presence of oxidative stress. Disclosures No relevant conflicts of interest to declare.
28
Guo, Rui, Rui Si, Brian T. Scott, and Ayako Makino. "Mitochondrial connexin40 regulates mitochondrial calcium uptake in coronary endothelial cells." American Journal of Physiology-Cell Physiology 312, no. 4 (April 1, 2017): C398—C406. http://dx.doi.org/10.1152/ajpcell.00283.2016.
Full textAbstract:
Connexins (Cxs) are a group of integral membrane proteins that can form gap junctions between adjacent cells. Recently, it was reported that Cx43 is expressed not only in the plasma membrane but also in the inner mitochondrial membrane and that it regulates mitochondrial functions. Cx40 is predominantly expressed in vascular endothelial cells (ECs) and plays an important role in the electrical propagation between ECs and endothelial/smooth muscle cells. However, it is unknown whether Cx40 is expressed in the mitochondria and what the role of mitochondrial Cx40 is in endothelial functions. We observed in coronary ECs that Cx40 protein was expressed in the mitochondria, as determined by Western blot and immunofluorescence studies. We found that mouse coronary ECs (MCECs) isolated from Cx40 knockout (Cx40 KO) mice exhibited significantly lower resting mitochondrial calcium concentration ([Ca2+]mito) than MCECs from wild-type (WT) mice. After increase in cytosolic Ca2+ concentration ([Ca2+]cyto) with cyclopiazonic acid, calcium uptake into the mitochondria was significantly attenuated in MCECs from Cx40 KO mice compared with WT MCECs. There was no difference in resting [Ca2+]cyto and store-operated calcium entry in MCECs from WT and Cx40 KO mice. We also detected a significant decrease in the concentration of mitochondrial reactive oxygen species (ROS) in Cx40 KO MCECs. Cx40 overexpression in ECs significantly increased resting [Ca2+]mito level and calcium uptake by mitochondria in response to increased [Ca2+]cyto and augmented mitochondrial ROS production. These data suggest that mitochondrial Cx40 contributes to the regulation of mitochondrial calcium homeostasis.
29
Shimada, Keisuke, Soojin Park, Haruhiko Miyata, Zhifeng Yu, Akane Morohoshi, Seiya Oura, Martin M. Matzuk, and Masahito Ikawa. "ARMC12 regulates spatiotemporal mitochondrial dynamics during spermiogenesis and is required for male fertility." Proceedings of the National Academy of Sciences 118, no. 6 (February 3, 2021): e2018355118. http://dx.doi.org/10.1073/pnas.2018355118.
Full textAbstract:
The mammalian sperm midpiece has a unique double-helical structure called the mitochondrial sheath that wraps tightly around the axoneme. Despite the remarkable organization of the mitochondrial sheath, the molecular mechanisms involved in mitochondrial sheath formation are unclear. In the process of screening testis-enriched genes for functions in mice, we identified armadillo repeat-containing 12 (ARMC12) as an essential protein for mitochondrial sheath formation. Here, we engineered Armc12-null mice, FLAG-tagged Armc12 knock-in mice, and TBC1 domain family member 21 (Tbc1d21)-null mice to define the functions of ARMC12 in mitochondrial sheath formation in vivo. We discovered that absence of ARMC12 causes abnormal mitochondrial coiling along the flagellum, resulting in reduced sperm motility and male sterility. During spermiogenesis, sperm mitochondria in Armc12-null mice cannot elongate properly at the mitochondrial interlocking step which disrupts abnormal mitochondrial coiling. ARMC12 is a mitochondrial peripheral membrane protein and functions as an adherence factor between mitochondria in cultured cells. ARMC12 in testicular germ cells interacts with mitochondrial proteins MIC60, VDAC2, and VDAC3 as well as TBC1D21 and GK2, which are required for mitochondrial sheath formation. We also observed that TBC1D21 is essential for the interaction between ARMC12 and VDAC proteins in vivo. These results indicate that ARMC12 uses integral mitochondrial membrane proteins VDAC2 and VDAC3 as scaffolds to link mitochondria and works cooperatively with TBC1D21. Thus, our studies have revealed that ARMC12 regulates spatiotemporal mitochondrial dynamics to form the mitochondrial sheath through cooperative interactions with several proteins on the sperm mitochondrial surface.
30
Varghese, Merina, Wei Zhao, Jun Wang, Alice Cheng, Xianjuan Qian, Amna Chaudhry, Lap Ho, and Giulio Pasinetti. "Mitochondrial bioenergetics is defective in presymptomatic Tg2576 AD Mice." Translational Neuroscience 2, no. 1 (January 1, 2011): 1–5. http://dx.doi.org/10.2478/s13380-011-0011-8.
Full textAbstract:
AbstractAlzheimer’s disease (AD) is an age-related dementia, with the pathological hallmarks of neuritic plaques and neurofibrillary tangles, brain atrophy and loss of synaptic terminals. Dysfunctional mitochondrial bioenergetics is implicated as a contributing factor to the cognitive decline observed in AD. We hypothesized that, in the presence of the AD neurotoxic peptide beta-amyloid, mitochondrial respiration is impaired early in synaptic terminals, which are vital to cognitive performance, preferentially in cognitive centers of the brain. We compared oxygen consumption in synaptosomal and perikaryal mitochondria prepared from the cerebral cortex and cerebellum of wild type (WT) and AD transgenic Tg2576 mice. Compared to WT mice, Tg2576 mice showed decreased mitochondrial respiration in the cerebral cortex specifically in synaptosomal fraction, while the perikaryal mitochondria were unaffected. Neither mitochondrial fraction was affected in the cerebellum of Tg2576 mice as compared to WT. The occurrence of a bioenergetic defect in synaptic terminals of mice overexpressing mutant beta-amyloid, in particular in an area of the brain important to cognition, points to an early role of mitochondrial defects in the onset of cognitive deficits in AD.
31
Harrington, Monica. "Mice, mitochondria and myopathy." Lab Animal 37, no. 10 (October 2008): 440. http://dx.doi.org/10.1038/laban1008-440a.
Full text
32
Holding, Cathy. "Of mice and mitochondria." Genome Biology 4 (2003): spotlight—20030522–01. http://dx.doi.org/10.1186/gb-spotlight-20030522-01.
Full text
33
Amin, Shaimaa Nasr. "Platelets: the peripheral donor of mitochondria for diabetes-induced cognitive impairment." Clinical Science 135, no. 4 (February 2021): 593–95. http://dx.doi.org/10.1042/cs20201297.
Full textAbstract:
Abstract This commentary highlights the research entitled: Transplantation of platelet-derived mitochondria alleviates cognitive impairment and mitochondrial dysfunction in db/db mice, presented by Ma et al. appearing in Clinical Science (2020) 134(16), https://doi.org/10.1042/CS20200530. The authors evaluated the effect of xenograft transplantation of mitochondria isolated from peripheral blood platelets in an animal model of type II diabetes and evaluated the effects of transplantation on diabetes-associated cognitive impairment (DACI). They showed cognitive and molecular improvement in response to mitochondrial transplantation to db/db mice brains. Besides, they showed better internalization of the transplanted mitochondria into the diseased animals’ hippocampal cells compared with the healthy normal control.
34
Monemdjou, Shadi, Leslie P. Kozak, and Mary-Ellen Harper. "Mitochondrial proton leak in brown adipose tissue mitochondria of Ucp1-deficient mice is GDP insensitive." American Journal of Physiology-Endocrinology and Metabolism 276, no. 6 (June 1, 1999): E1073—E1082. http://dx.doi.org/10.1152/ajpendo.1999.276.6.e1073.
Full textAbstract:
Mice deficient in mitochondrial uncoupling protein (UCP) 1 are cold sensitive, despite abundant expression of the homologues, Ucp2 and Ucp3 (S. Enerbäck, A. Jacobsson, E. M. Simpson, C. Guerra, H. Yamashita, M.-E. Harper, and L. P. Kozak. Nature 387: 90–94, 1997). We have analyzed characteristics of mitochondrial proton leak from brown adipose tissue (BAT) of Ucp1-deficient mice and normal controls and conducted the first top-down metabolic control analysis of oxidative phosphorylation in BAT mitochondria. Because purine nucleotides inhibit UCP1 and because UCP2 and the long form of UCP3 have putative purine nucleotide-binding regions, we predicted that proton leak in BAT mitochondria from Ucp1-deficient mice would be sensitive to GDP. On the contrary, although control over mitochondrial oxygen consumption and proton leak reactions at state 4 are strongly affected by 1 mM GDP in mitochondria from normal mice, there is no effect in UCP1-deficient mitochondria. In the presence of GDP, the overall kinetics of proton leak were not significantly different between Ucp1-deficient mice and controls. In its absence, state 4 respiration in normal BAT mitochondria was double that in its presence. Leak-dependent oxygen consumption was higher over a range of membrane potentials in its absence than in its presence. Thus proton leak, potentially including that through UCP2 and UCP3, is GDP insensitive. However, our measurements were made in the presence of albumin and may not allow for the detection of any fatty acid-induced UCP-mediated leak; this possibility requires investigation.
35
Wang, Qiang, Ann M. Ratchford, Maggie M. Y. Chi, Erica Schoeller, Antonina Frolova, Tim Schedl, and Kelle H. Moley. "Maternal Diabetes Causes Mitochondrial Dysfunction and Meiotic Defects in Murine Oocytes." Molecular Endocrinology 23, no. 10 (October 1, 2009): 1603–12. http://dx.doi.org/10.1210/me.2009-0033.
Full textAbstract:
Abstract The adverse effects of maternal diabetes on embryo development and pregnancy outcomes have recently been shown to occur as early as the one-cell zygote stage. The hypothesis of this study was that maternally inherited mitochondria in oocytes from diabetic mice are abnormal and thus responsible in part for this latency of developmental compromise. In ovulated oocytes from diabetic mice, transmission electron microscopy revealed an alteration in mitochondrial ultrastructure, and the quantitative analysis of mitochondrial DNA copy number demonstrated an increase. The levels of ATP and tricarboxylic acid cycle metabolites in diabetic oocytes were markedly reduced compared with controls, suggesting a mitochondrial metabolic dysfunction. Abnormal distribution of mitochondria within maturing oocytes also was seen in diabetic mice. Furthermore, oocytes from diabetic mice displayed a higher frequency of spindle defects and chromosome misalignment in meiosis, resulting in increased aneuploidy rates in ovulated oocytes. Collectively, our results suggest that maternal diabetes results in oocyte defects that are transmitted to the fetus by two routes: first, meiotic spindle and chromatin defects result in nondisjunction leading to embryonic aneuploidy; second, structural and functional abnormalities of oocyte mitochondria, through maternal transmission, provide the embryo with a dysfunctional complement of mitochondria that may be propagated during embryogenesis.
36
Wang, Qiang, Ann M. Ratchford, Maggie M. Y. Chi, Erica Schoeller, Antonina Frolova, Tim Schedl, and Kelle H. Moley. "Maternal Diabetes Causes Mitochondrial Dysfunction and Meiotic Defects in Murine Oocytes." Journal of Clinical Endocrinology & Metabolism 94, no. 9 (September 1, 2009): 3618. http://dx.doi.org/10.1210/jcem.94.9.9995.
Full textAbstract:
The adverse effects of maternal diabetes on embryo development and pregnancy outcomes have recently been shown to occur as early as the one-cell zygote stage. The hypothesis of this study was that maternally inherited mitochondria in oocytes from diabetic mice are abnormal and thus responsible in part for this latency of developmental compromise. In ovulated oocytes from diabetic mice, transmission electron microscopy revealed an alteration in mitochondrial ultrastructure, and the quantitative analysis of mitochondrial DNA copy number demonstrated an increase. The levels of ATP and tricarboxylic acid cycle metabolites in diabetic oocytes were markedly reduced compared with controls, suggesting a mitochondrial metabolic dysfunction. Abnormal distribution of mitochondria within maturing oocytes also was seen in diabetic mice. Furthermore, oocytes from diabetic mice displayed a higher frequency of spindle defects and chromosome misalignment in meiosis, resulting in increased aneuploidy rates in ovulated oocytes. Collectively, our results suggest that maternal diabetes results in oocyte defects that are transmitted to the fetus by two routes: first, meiotic spindle and chromatin defects result in nondisjunction leading to embryonic aneuploidy; second, structural and functional abnormalities of oocyte mitochondria, through maternal transmission, provide the embryo with a dysfunctional complement of mitochondria that may be propagated during embryogenesis.
37
Ananthakrishnan, Radha, Michiyo Kaneko, Yuying C. Hwang, Nosirudeen Quadri, Teodoro Gomez, Qing Li, Casper Caspersen, and Ravichandran Ramasamy. "Aldose reductase mediates myocardial ischemia-reperfusion injury in part by opening mitochondrial permeability transition pore." American Journal of Physiology-Heart and Circulatory Physiology 296, no. 2 (February 2009): H333—H341. http://dx.doi.org/10.1152/ajpheart.01012.2008.
Full textAbstract:
Aldose reductase (AR), a member of the aldo-keto reductase family, has been demonstrated to play a central role in mediating myocardial ischemia-reperfusion (I/R) injury. Recently, using transgenic mice broadly overexpressing human AR (ARTg), we demonstrated that AR is an important component of myocardial I/R injury and that inhibition of this enzyme protects heart from I/R injury ( 20 – 22 , 48 , 49 , 56 ). To rigorously delineate mechanisms by which AR pathway influences myocardial ischemic injury, we investigated the role played by reactive oxygen species (ROS), antioxidant enzymes, and mitochondrial permeability transition (MPT) pore opening in hearts from ARTg or littermates [wild type (WT)] subjected to I/R. MPT pore opening after I/R was determined using mitochondrial uptake of 2-deoxyglucose ratio, while H2O2 was measured as a key indicator of ROS. Myocardial 2-deoxyglucose uptake ratio and calcium-induced swelling were significantly greater in mitochondria from ARTg mice than in WT mice. Blockade of MPT pore with cyclosphorin A during I/R reduced ischemic injury significantly in ARTg mice hearts. H2O2 measurements indicated mitochondrial ROS generation after I/R was significantly greater in ARTg mitochondria than in WT mice hearts. Furthermore, the levels of antioxidant GSH were significantly reduced in ARTg mitochondria than in WT. Resveratrol treatment or pharmacological blockade of AR significantly reduced ROS generation and MPT pore opening in mitochondria of ARTg mice hearts exposed to I/R stress. This study demonstrates that MPT pore opening is a key event by which AR pathway mediates myocardial I/R injury, and that the MPT pore opening after I/R is triggered, in part, by increases in ROS generation in ARTg mice hearts. Therefore, inhibition of AR pathway protects mitochondria and hence may be a useful adjunct for salvaging ischemic myocardium.
38
Wang, Xiaoxia, Chun Song, Xiao Zhou, Xiaorui Han, Jun Li, Zengwu Wang, Haibao Shang, Yuli Liu, and Huiqing Cao. "Mitochondria Associated MicroRNA Expression Profiling of Heart Failure." BioMed Research International 2017 (2017): 1–10. http://dx.doi.org/10.1155/2017/4042509.
Full textAbstract:
Heart failure (HF) is associated with mitochondrial dysfunction and energy metabolism impairment. MicroRNAs are implicated in the development of heart failure. However, the mitochondria enriched microRNA during heart failure remains elusive. Here, we generated a pressure overload-induced early and late stage heart failure model at 4 weeks and 8 weeks following transverse aortic constriction (TAC) in mice. We found that expression of mitochondrion protein COX4 was highly enriched in isolated mitochondria from cardiac tissues while GAPDH could hardly be detected. Furthermore, small RNA sequencing for mitochondria RNAs from failing hearts was performed. It was found that 69 microRNAs were upregulated and 2 were downregulated in early heart failure, while 16 microRNAs were upregulated and 6 were downregulated in late heart failure. 15 microRNA candidates were measured in both mitochondria and total cardiac tissues of heart failure by real-time PCR. MiR-696, miR-532, miR-690, and miR-345-3p were enriched in mitochondria from the failing heart at early stage. Bioinformatics analysis showed that mitochondria enriched microRNAs in HF were associated with energy metabolism and oxidative stress pathway. For the first time, we demonstrated microRNAs were enriched in mitochondria during heart failure, which established a link between microRNA and mitochondrion in heart failure.
39
Wang, Shanshan, Taiga Ichinomiya, Yuki Terada, Dongsheng Wang, Hemal H. Patel, and Brian P. Head. "Synapsin-Promoted Caveolin-1 Overexpression Maintains Mitochondrial Morphology and Function in PSAPP Alzheimer’s Disease Mice." Cells 10, no. 9 (September 20, 2021): 2487. http://dx.doi.org/10.3390/cells10092487.
Full textAbstract:
Mitochondrial dysfunction plays a pivotal role in the Alzheimer’s Disease (AD) pathology. Disrupted mitochondrial dynamics (i.e., fusion/fission balance), which are essential for normal mitochondria structure and function, are documented in AD. Caveolin-1 (Cav-1), a membrane/lipid raft (MLR) scaffolding protein regulates metabolic pathways in several different cell types such as hepatocytes and cancer cells. Previously, we have shown decreased expression of Cav-1 in the hippocampus of 9-month (m) old PSAPP mice, while hippocampal overexpression of neuron-targeted Cav-1 using the synapsin promoter (i.e., SynCav1) preserved cognitive function, neuronal morphology, and synaptic ultrastructure in 9 and 12 m PSAPP mice. Considering the central role of energy production in maintaining normal neuronal and synaptic function and survival, the present study reveals that PSAPP mice exhibit disrupted mitochondrial distribution, morphometry, and respiration. In contrast, SynCav1 mitigates mitochondrial damage and loss and enhances mitochondrial respiration. Furthermore, by examining mitochondrial dynamics, we found that PSAPP mice showed a significant increase in the phosphorylation of mitochondrial dynamin-related GTPase protein (DRP1), resulting in excessive mitochondria fragmentation and dysfunction. In contrast, hippocampal delivery of SynCav1 significantly decreased p-DRP1 and augmented the level of the mitochondrial fusion protein, mitofusin1 (Mfn1) in PSAPP mice, a molecular event, which may mechanistically explain for the preserved balance of mitochondria fission/fusion and metabolic resilience in 12 m PSAPP-SynCav1 mice. Our data demonstrate the critical role for Cav-1 in maintaining normal mitochondrial morphology and function through affecting mitochondrial dynamics and explain a molecular and cellular mechanism underlying the previously reported neuroprotective and cognitive preservation induced by SynCav1 in PSAPP mouse model of AD.
40
Park, Min, Takanori Nishimura, Carlos D. Baeza-Garza, Stuart T. Caldwell, Pamela Boon Li Pun, Hiran A. Prag, Tim Young, et al. "Confirmation of the Cardioprotective Effect of MitoGamide in the Diabetic Heart." Cardiovascular Drugs and Therapy 34, no. 6 (September 26, 2020): 823–34. http://dx.doi.org/10.1007/s10557-020-07086-7.
Full textAbstract:
Abstract Purpose HFpEF (heart failure with preserved ejection fraction) is a major consequence of diabetic cardiomyopathy with no effective treatments. Here, we have characterized Akita mice as a preclinical model of HFpEF and used it to confirm the therapeutic efficacy of the mitochondria-targeted dicarbonyl scavenger, MitoGamide. Methods and Results A longitudinal echocardiographic analysis confirmed that Akita mice develop diastolic dysfunction with reduced E peak velocity, E/A ratio and extended isovolumetric relaxation time (IVRT), while the systolic function remains comparable with wild-type mice. The myocardium of Akita mice had a decreased ATP/ADP ratio, elevated mitochondrial oxidative stress and increased organelle density, compared with that of wild-type mice. MitoGamide, a mitochondria-targeted 1,2-dicarbonyl scavenger, exhibited good stability in vivo, uptake into cells and mitochondria and reactivity with dicarbonyls. Treatment of Akita mice with MitoGamide for 12 weeks significantly improved the E/A ratio compared with the vehicle-treated group. Conclusion Our work confirms that the Akita mouse model of diabetes replicates key clinical features of diabetic HFpEF, including cardiac and mitochondrial dysfunction. Furthermore, in this independent study, MitoGamide treatment improved diastolic function in Akita mice.
41
Belosludtseva, Natalia V., Vlada S. Starinets, Lyubov L. Pavlik, Irina B. Mikheeva, Mikhail V. Dubinin, and Konstantin N. Belosludtsev. "The Effect of S-15176 Difumarate Salt on Ultrastructure and Functions of Liver Mitochondria of C57BL/6 Mice with Streptozotocin/High-Fat Diet-Induced Type 2 Diabetes." Biology 9, no. 10 (September 24, 2020): 309. http://dx.doi.org/10.3390/biology9100309.
Full textAbstract:
S-15176, a potent derivative of the anti-ischemic agent trimetazidine, was reported to have multiple effects on the metabolism of mitochondria. In the present work, the effect of S-15176 (1.5 mg/kg/day i.p.) on the ultrastructure and functions of liver mitochondria of C57BL/6 mice with type 2 diabetes mellitus (T2DM) induced by a high-fat diet combined with a low-dose streptozotocin injection was examined. An electron microscopy study showed that T2DM induced mitochondrial swelling and a reduction in the number of liver mitochondria. The number of mtDNA copies in the liver in T2DM decreased. The expression of Drp1 slightly increased, and that of Mfn2 and Opa1 somewhat decreased. The treatment of diabetic animals with S-15176 prevented the mitochondrial swelling, normalized the average mitochondrial size, and significantly decreased the content of the key marker of lipid peroxidation malondialdehyde in liver mitochondria. In S-15176-treated T2DM mice, a two-fold increase in the expression of the PGC-1α and a slight decrease in Drp 1 expression in the liver were observed. The respiratory control ratio, the level of mtDNA, and the number of liver mitochondria of S-15176-treated diabetic mice tended to restore. S-15176 did not affect the decrease in expression of Parkin and Opa1 in the liver of diabetic animals, but slightly suppressed the expression of these proteins in the control. The modulatory effect of S-15176 on dysfunction of liver mitochondria in T2DM can be related to the stimulation of mitochondrial biogenesis and the inhibition of lipid peroxidation in the organelles.
42
Winter, Lilli, Christina Abrahamsberg, and Gerhard Wiche. "Plectin isoform 1b mediates mitochondrion–intermediate filament network linkage and controls organelle shape." Journal of Cell Biology 181, no. 6 (June 9, 2008): 903–11. http://dx.doi.org/10.1083/jcb.200710151.
Full textAbstract:
Plectin is a versatile intermediate filament (IF)–bound cytolinker protein with a variety of differentially spliced isoforms accounting for its multiple functions. One particular isoform, plectin 1b (P1b), remains associated with mitochondria after biochemical fractionation of fibroblasts and cells expressing exogenous P1b. Here, we determined that P1b is inserted into the outer mitochondrial membrane with the exon 1b–encoded N-terminal sequence serving as a mitochondrial targeting and anchoring signal. To study P1b-related mitochondrial functions, we generated mice that selectively lack this isoform but express all others. In primary fibroblasts and myoblasts derived from these mice, we observe a substantial elongation of mitochondrial networks, whereas other mitochondrial properties remain largely unaffected. Normal morphology of mitochondria could be restored by isoform-specific overexpression of P1b in P1b-deficient as well as plectin-null cells. We propose a model where P1b both forms a mitochondrial signaling platform and affects organelle shape and network formation by tethering mitochondria to IFs.
43
Kappler, Lisa, Miriam Hoene, Chunxiu Hu, Christine von Toerne, Jia Li, Daniel Bleher, Christoph Hoffmann, et al. "Linking bioenergetic function of mitochondria to tissue-specific molecular fingerprints." American Journal of Physiology-Endocrinology and Metabolism 317, no. 2 (August 1, 2019): E374—E387. http://dx.doi.org/10.1152/ajpendo.00088.2019.
Full textAbstract:
Mitochondria are dynamic organelles with diverse functions in tissues such as liver and skeletal muscle. To unravel the mitochondrial contribution to tissue-specific physiology, we performed a systematic comparison of the mitochondrial proteome and lipidome of mice and assessed the consequences hereof for respiration. Liver and skeletal muscle mitochondrial protein composition was studied by data-independent ultra-high-performance (UHP)LC-MS/MS-proteomics, and lipid profiles were compared by UHPLC-MS/MS lipidomics. Mitochondrial function was investigated by high-resolution respirometry in samples from mice and humans. Enzymes of pyruvate oxidation as well as several subunits of complex I, III, and ATP synthase were more abundant in muscle mitochondria. Muscle mitochondria were enriched in cardiolipins associated with higher oxidative phosphorylation capacity and flexibility, in particular CL(18:2)4 and 22:6-containing cardiolipins. In contrast, protein equipment of liver mitochondria indicated a shuttling of complex I substrates toward gluconeogenesis and ketogenesis and a higher preference for electron transfer via the flavoprotein quinone oxidoreductase pathway. Concordantly, muscle and liver mitochondria showed distinct respiratory substrate preferences. Muscle respired significantly more on the complex I substrates pyruvate and glutamate, whereas in liver maximal respiration was supported by complex II substrate succinate. This was a consistent finding in mouse liver and skeletal muscle mitochondria and human samples. Muscle mitochondria are tailored to produce ATP with a high capacity for complex I-linked substrates. Liver mitochondria are more connected to biosynthetic pathways, preferring fatty acids and succinate for oxidation. The physiologic diversity of mitochondria may help to understand tissue-specific disease pathologies and to develop therapies targeting mitochondrial function.
44
Lopez-Manzaneda, Mario, Julio Franco-Espin, Rocio Tejero, Raquel Cano, and Lucia Tabares. "Calcium is reduced in presynaptic mitochondria of motor nerve terminals during neurotransmission in SMA mice." Human Molecular Genetics 30, no. 8 (March 9, 2021): 629–43. http://dx.doi.org/10.1093/hmg/ddab065.
Full textAbstract:
Abstract Spinal muscular atrophy (SMA) is an autosomal recessive degenerative motor neuron disease characterized by symmetrical muscle weakness and atrophy of limb and trunk muscles being the most severe genetic disease in children. In SMA mouse models, motor nerve terminals display neurotransmitter release reduction, endocytosis decrease and mitochondria alterations. The relationship between these changes is, however, not well understood. In the present study, we investigated whether the endocytosis impairment could be related to the functional alteration of the presynaptic mitochondria during action potential (AP) firing. To this aim, we generated a Synaptophysin-pHluorin (SypHy) transgenic mouse, crossed it with Taiwanese SMA mice, and recorded exo- and endocytosis and mitochondria Ca2+ signaling in real-time at ex vivo motor nerve terminals of Taiwanese-SypHy mice. The experiments were performed at the beginning of the motor symptoms to get an integrated view of the nerve terminal’s functional state before degeneration. Our electrophysiological and live imaging results demonstrated that the mitochondria’s capacity to increase matrix-free Ca2+ in SMA mice was significantly limited during nerve AP firing, except when the rate of Ca2+ entry to the cytosol was considerably reduced. These results indicate that both the mitochondrial Ca2+ signaling alterations and the secretion machinery defects are significant players in the dysfunction of the presynaptic terminal in SMA.
45
Singh, Abhishek K., Karin Golan, Mark J. Althoff, Ekaterina Petrovich-Kopitman, Ashley M. Wellendorf, Fatima Mohmoud, Mayla Bertagna, et al. "Bone Marrow Hematopoietic Connexin 43 Is Required for Mitotransfer and AMPK Dependent Mesenchymal Microenvironment Regeneration after Irradiation." Blood 132, Supplement 1 (November 29, 2018): 872. http://dx.doi.org/10.1182/blood-2018-99-118292.
Full textAbstract:
Abstract Hematopoietic stem cell/progenitor (HSCP) transplantation (HSCT) is routinely used for the treatment of cancer and inborn hematopoietic defects. The bone marrow (BM) microenvironment (ME) is a major regulator of hematopoietic function and fate. Clinical data supports osteoblastic regeneration after HSCT despite the inability of BM mesenchymal stem cells (BM-MSC) to engraft. Therefore, understanding the hematopoietic-dependent mechanisms controlling ME mesenchymal regeneration is expected to provide molecular targets for intervention in the context of HSCT. Hematopoietic connexin-43 (H-Cx43) mediates HSCP survival and efficient blood formation by scavenging damaging excess reactive oxygen species (ROS) through transfer to BM mesenchymal stromal cells (BM-MSC) after chemotherapy, preventing lethal hematopoietic failure (Taniguchi-Ishikwawa E et al., PNAS 2012), while the expression of Cx43 on BM-MSC regulates CXCL12 secretion and HSCP homeostasis (Schajnovitz A et al., Nat. Immunol., 2011). Since Cx43 is expressed in mitochondria, we hypothesized that H-Cx43 mediated ROS transfer upon stress depends on hematopoietic mitochondria transfer and uptake by the BM-MSC. We created chimeric mice by transplanting Vav1-CreTg/-, Cox8 mitochondrial localization signal-Dendra2Tg/- wild-type (mDendra2/WT) or Cx43fl/fl(mDendra2/Cx43Δ/Δ) HSCP to lethally irradiated, congenic WT mice and assessed the recovery of stromal cell regeneration via transfer of mitochondria to BM-MSC. H-Cx43Δ/Δchimeric mice have delayed lympho-hematopoietic recovery after irradiation or chemotherapy which can be reversed by restoration of hematopoietic Cx43 expression. H-Cx43Δ/Δchimeric mice exhibit decreased (~60-80%) and delayed colony-forming-unit-fibroblast (CFU-F) and osteoblast (CFU-Ob) regeneration and hematopoietic recovery. The delayed hematopoietic response in H-Cx43Δ/Δchimeras associated with ~40% reduction in mitochondrial transfer from HSCP to Lin-/CD45-/PDGFRα+/Sca1- BM stromal cells (MSC/P). Reverse transplantation experiments indicate that stromal Cx43 is dispensable for mitochondrial transfer from BM stroma to HSCP. Impaired mitochondrial uptake in H-Cx43Δ/Δchimeras associated with ~30-40% decreased mitochondrial ROS (mROS), membrane potential (MMP) and proliferation (assessed by in vivo BrdU uptake) of recipient MSC/P, suggesting that the transferred mitochondria reprogram the recipient mesenchymal progenitor metabolism. Defects of mitotransfer from H-Cx43Δ/ΔHSCP to BM MSC/P and in recipient BM MSC/P mitochondrial activity were recapitulated in in vitro co-cultures. Interestingly, intracellular [ATP] is upregulated (~2 fold) in MSC/P from chimeric H-Cx43Δ/ΔBM that received donor-derived mitochondria, as compared to donor mitochondria containing MSC/P from WTchimeras. Hemichannel opening causes loss of ATP, we therefore speculated that ATP released from MSC/P upon irradiation and transplantation is uptaken by HSPC, activating mitochondrial transfer as part of BM regeneration. Forced glycolysis-dependent restoration of [ATP] in MSC/P but not in HSCP enhances transfer of mitochondria from HSCP to MSC/P, suggesting that BM stromal [ATP] is an irradiation-responsive positive regulator of mitochondria transfer. Hemichannel-derived exogenous ATP suppresses AMPK activation, which regulates cellular metabolic homeostasis by modulating mitochondrial ROS, mitochondria dynamics and the fate of mitochondria. We found that MSC/P recipient of H-Cx43Δ/Δ mitochondria have increased AMPK activity as assessed by increased phosphorylation of AMPK and its downstream effectors ULK1 and ACC (~2-fold) when compared with MSC/P recipient of H-WT mitochondria, whereas MSC/P containing no donor-derived mitochondria from either chimeric mice are insensitive to the effect of Cx43 deficiency. In vivo administration of the AMPK inhibitor BML-275 dramatically increased the mitochondria transfer from HSCP to MSC/P in WT and H-Cx43Δ/Δ chimeras, and completely restores the negative effect of H-Cx43 deficiency on BM mesenchymal and hematopoietic regeneration. Our data indicate that hematopoietic mitochondrial Cx43 is required to control both mitochondrial transfer and BM ME energetic balance and regeneration after myeloablative irradiation. Disclosures No relevant conflicts of interest to declare.
46
Cohen, N. S., C. W. Cheung, and L. Raijman. "Altered enzyme activities and citrulline synthesis in liver mitochondria from ornithine carbamoyltransferase-deficient sparse-furash mice." Biochemical Journal 257, no. 1 (January 1, 1989): 251–57. http://dx.doi.org/10.1042/bj2570251.
Full textAbstract:
Male mice carrying the spfash mutation have 5-10% of the normal activity of ornithine carbamoyltransferase, yet are only slightly hyperammonaemic and develop quite well. A study of liver mitochondria from normal and spfash males showed that they differ in important ways. (1) The spfash liver contains about 33% more mitochondrial protein per g than does normal liver. (2) The specific activities of carbamoyl-phosphate synthetase (ammonia) and glutamate dehydrogenase are about 15% lower than normal in mitochondria from spfash mice, whereas those of beta-hydroxybutyrate dehydrogenase and cytochrome oxidase are 22% higher and 30% lower respectively. (3) In the presence of 10 mM-ornithine and the substrates for carbamoyl phosphate synthesis, coupled and uncoupled mitochondria from spfash mice synthesize citrulline at unexpectedly high rates, about 25 and 44 nmol/min per mg respectively. Though these are somewhat lower than the corresponding rates obtained with normal mitochondria, the difference does not arise from the deficiency in ornithine carbamoyltransferase, but from the lower carbamoyl-phosphate synthetase activity of the mutant mitochondria. (4) At lower external [ornithine] (less than 2 mM), a smaller fraction of the carbamoyl phosphate synthesized is converted into citrulline in spfash than in normal mitochondria. These studies show that what appears to be a single mutation brings about major adaptations in the mitochondrial component of liver. In addition, they clarify the role of ornithine transport and of protein-protein interactions in citrulline synthesis in normal mitochondria.
47
Szarek, Eva, Evan R. Ball, Alessio Imperiale, Maria Tsokos, Fabio R. Faucz, Alessio Giubellino, François-Marie Moussallieh, et al. "Carney triad, SDH-deficient tumors, and Sdhb+/− mice share abnormal mitochondria." Endocrine-Related Cancer 22, no. 3 (March 25, 2015): 345–52. http://dx.doi.org/10.1530/erc-15-0069.
Full textAbstract:
Carney triad (CTr) describes the association of paragangliomas (PGL), pulmonary chondromas, and gastrointestinal (GI) stromal tumors (GISTs) with a variety of other lesions, including pheochromocytomas and adrenocortical tumors. The gene(s) that cause CTr remain(s) unknown. PGL and GISTs may be caused by loss-of-function mutations in succinate dehydrogenase (SDH) (a condition known as Carney–Stratakis syndrome (CSS)). Mitochondrial structure and function are abnormal in tissues that carry SDH defects, but they have not been studied in CTr. For the present study, we examined mitochondrial structure in human tumors and GI tissue (GIT) of mice with SDH deficiency. Tissues from 16 CTr tumors (n=12), those with isolated GIST (n=1), and those with CSS caused bySDHC(n=1) andSDHD(n=2) mutations were studied by electron microscopy (EM). Samples of GIT from mice with a heterozygous deletion inSdhb(Sdhb+/−,n=4) were also studied by EM. CTr patients presented with mostly epithelioid GISTs that were characterized by plump cells containing a centrally located, round nucleus and prominent nucleoli; these changes were almost identical to those seen in the GISTs of patients with SDH. In tumor cells from patients, regardless of diagnosis or tumor type, cytoplasm contained an increased number of mitochondria with a ‘hypoxic’ phenotype: mitochondria were devoid of cristae, exhibited structural abnormalities, and were of variable size. Occasionally, mitochondria were small and round; rarely, they were thin and elongated with tubular cristae. Many mitochondria exhibited amorphous fluffy material with membranous whorls or cystic structures. A similar mitochondrial hypoxic phenotype was seen inSdhb+/−mice. We concluded that tissues from SDH-deficient tumors, those from mouse GIT, and those from CTr tumors shared identical abnormalities in mitochondrial structure and other features. Thus, the still-elusive CTr defect(s) is(are) likely to affect mitochondrial function, just like germline SDH-deficiency does.
48
Dubinin, Mikhail V., Vlada S. Starinets, Eugeny Yu Talanov, Irina B. Mikheeva, Natalia V. Belosludtseva, and Konstantin N. Belosludtsev. "Alisporivir Improves Mitochondrial Function in Skeletal Muscle of mdx Mice but Suppresses Mitochondrial Dynamics and Biogenesis." International Journal of Molecular Sciences 22, no. 18 (September 10, 2021): 9780. http://dx.doi.org/10.3390/ijms22189780.
Full textAbstract:
Mitigation of calcium-dependent destruction of skeletal muscle mitochondria is considered as a promising adjunctive therapy in Duchenne muscular dystrophy (DMD). In this work, we study the effect of intraperitoneal administration of a non-immunosuppressive inhibitor of calcium-dependent mitochondrial permeability transition (MPT) pore alisporivir on the state of skeletal muscles and the functioning of mitochondria in dystrophin-deficient mdx mice. We show that treatment with alisporivir reduces inflammation and improves muscle function in mdx mice. These effects of alisporivir were associated with an improvement in the ultrastructure of mitochondria, normalization of respiration and oxidative phosphorylation, and a decrease in lipid peroxidation, due to suppression of MPT pore opening and an improvement in calcium homeostasis. The action of alisporivir was associated with suppression of the activity of cyclophilin D and a decrease in its expression in skeletal muscles. This was observed in both mdx mice and wild-type animals. At the same time, alisporivir suppressed mitochondrial biogenesis, assessed by the expression of Ppargc1a, and altered the dynamics of organelles, inhibiting both DRP1-mediated fission and MFN2-associated fusion of mitochondria. The article discusses the effects of alisporivir administration and cyclophilin D inhibition on mitochondrial reprogramming and networking in DMD and the consequences of this therapy on skeletal muscle health.
49
Shibata, Mamoru, Yohei Kayama, Tsubasa Takizawa, Keiji Ibata, Toshihiko Shimizu, Michisuke Yuzaki, Norihiro Suzuki, and Jin Nakahara. "Resilience to capsaicin-induced mitochondrial damage in trigeminal ganglion neurons." Molecular Pain 16 (January 2020): 174480692096085. http://dx.doi.org/10.1177/1744806920960856.
Full textAbstract:
Capsaicin is an agonist of transient receptor potential cation channel subfamily V member 1 (TRPV1). Strong TRPV1 stimulation with capsaicin causes mitochondrial damage in primary sensory neurons. However, the effect of repetitive and moderate exposure to capsaicin on the integrity of neuronal mitochondria remains largely unknown. Our electron microscopic analysis revealed that repetitive stimulation of the facial skin of mice with 10 mM capsaicin induced short-term damage to the mitochondria in small-sized trigeminal ganglion neurons. Further, capsaicin-treated mice exhibited decreased sensitivity to noxious heat stimulation, indicating TRPV1 dysfunction, in parallel with the mitochondrial damage in the trigeminal ganglion neurons. To analyze the capsaicin-induced mitochondrial damage and its relevant cellular events in detail, we performed cell-based assays using TRPV1-expressing PC12 cells. Dose-dependent capsaicin-mediated mitochondrial toxicity was observed. High doses of capsaicin caused rapid destruction of mitochondrial internal structure, while low doses induced mitochondrial swelling. Further, capsaicin induced a dose-dependent loss of mitochondria and autophagy-mediated degradation of mitochondria (mitophagy). Concomitantly, transcriptional upregulation of mitochondrial proteins, cytochrome c oxidase subunit IV, Mic60/Mitofilin, and voltage-dependent anion channel 1 was observed, which implied induction of mitochondrial biogenesis to compensate for the loss of mitochondria. Collectively, although trigeminal ganglion neurons transiently exhibit mitochondrial damage and TRPV1 dysfunction following moderate capsaicin exposure, they appear to be resilient to such a challenge. Our in vitro data show a dose–response relationship in capsaicin-mediated mitochondrial toxicity. We postulate that induction of mitophagy and mitochondrial biogenesis in response to capsaicin stimulation play important roles in repairing the damaged mitochondrial system.
50
Hoeft, Konrad, Donald B. Bloch, Jan A. Graw, Rajeev Malhotra, Fumito Ichinose, and Aranya Bagchi. "Iron Loading Exaggerates the Inflammatory Response to the Toll-like Receptor 4 Ligand Lipopolysaccharide by Altering Mitochondrial Homeostasis." Anesthesiology 127, no. 1 (July 1, 2017): 121–35. http://dx.doi.org/10.1097/aln.0000000000001653.
Full textAbstract:
Abstract Background Perioperative and critically ill patients are often exposed to iron (in the form of parenteral-iron administration or blood transfusion) and inflammatory stimuli, but the effects of iron loading on the inflammatory response are unclear. Recent data suggest that mitochondrial reactive oxygen species have an important role in the innate immune response and that increased mitochondrial reactive oxygen species production is a result of dysfunctional mitochondria. We tested the hypothesis that increased intracellular iron potentiates lipopolysaccharide-induced inflammation by increasing mitochondrial reactive oxygen species levels. Methods Murine macrophage cells were incubated with iron and then stimulated with lipopolysaccharide. C57BL/6 wild-type mice were intraperitoneally injected with iron and then with lipopolysaccharide. Markers of inflammation and mitochondrial superoxide production were examined. Mitochondrial homeostasis (the balance between mitochondrial biogenesis and destruction) was assessed, as were mitochondrial mass and the proportion of nonfunctional to total mitochondria. Results Iron loading of mice and cells potentiated the inflammatory response to lipopolysaccharide. Iron loading increased mitochondrial superoxide production. Treatment with MitoTEMPO, a mitochondria-specific antioxidant, blunted the proinflammatory effects of iron loading. Iron loading increased mitochondrial mass in cells treated with lipopolysaccharide and increased the proportion of nonfunctional mitochondria. Iron loading also altered mitochondrial homeostasis to favor increased production of mitochondria. Conclusions Acute iron loading potentiates the inflammatory response to lipopolysaccharide, at least in part by disrupting mitochondrial homeostasis and increasing the production of mitochondrial superoxide. Improved understanding of iron homeostasis in the context of acute inflammation may yield innovative therapeutic approaches in perioperative and critically ill patients.