scholarly journals Generation of the mitochondrial permeability transition does not involve inhibition of lysophospholipid acylation. Acyl-coenzyme A:1-acyllysophospholipid acyltransferase activity is not found in rat liver mitochondria.

1991 ◽  
Vol 266 (31) ◽  
pp. 20700-20708
Author(s):  
K.M. Broekemeier ◽  
P.C. Schmid ◽  
M.E. Dempsey ◽  
D.R. Pfeiffer
Author(s):  
Marina R. Sartori ◽  
Claudia D.C. Navarro ◽  
Roger F. Castilho ◽  
Anibal E. Vercesi

The interaction between supraphysiological cytosolic Ca2+ levels and mitochondrial redox imbalance mediates the mitochondrial permeability transition (MPT). MPT is involved in cell death, diseases, and aging. This study compared the liver mitochondrial Ca2+ retention capacity and oxygen consumption in the long-lived red-footed tortoise (Chelonoidis carbonaria) to the rat as a reference standard. Mitochondrial Ca2+ retention capacity, a quantitative measure of MPT sensitivity, was remarkably higher in tortoises than rats. This difference was minimized in the presence of the MPT inhibitors, ADP and cyclosporine A. However, the Ca2+ retention capacities of tortoise and rat liver mitochondria were similar when both MPT inhibitors were present simultaneously. NADH-linked phosphorylating respiration rates of tortoise liver mitochondria represented only 30% of the maximal electron transport system capacity, indicating a limitation imposed by the phosphorylation system. These results suggested underlying differences in putative MPT structural components (e.g. ATP synthase, adenine nucleotide translocase (ANT), and cyclophilin D) between tortoises and rats. Indeed, in tortoise mitochondria, titrations of inhibitors of the oxidative phosphorylation components revealed a higher limitation of ANT. Furthermore, cyclophilin D activity was approximately 70% lower in tortoises than in rats. Investigation of critical properties of mitochondrial redox control that affect MPT demonstrated that tortoise and rat liver mitochondria exhibited similar rates of H2O2 release and glutathione redox status. Overall, our findings suggest that constraints imposed by ANT and cyclophilin D, putative components or regulators of the MPT pore, are associated with the enhanced resistance to Ca2+-induced MPT in tortoises.


Cells ◽  
2020 ◽  
Vol 9 (8) ◽  
pp. 1774
Author(s):  
Yulia Baburina ◽  
Irina Odinokova ◽  
Olga Krestinina

Decades of active research have shown that mitochondrial dysfunction, the associated oxidative stress, impaired anti-stress defense mechanisms, and the activation of the proapoptotic signaling pathways underlie pathological changes in organs and tissues. Pathologies caused by alcohol primarily affect the liver. Alcohol abuse is the cause of many liver diseases, such as steatosis, alcoholic steatohepatitis, fibrosis, cirrhosis, and, potentially, hepatocellular cancer. In this study, the effect of chronic alcohol exposure on rat liver mitochondria was investigated. We observed an ethanol-induced increase in sensitivity to calcium, changes in the level of protein kinase Akt and GSK-3β phosphorylation, an induction of the mitochondrial permeability transition pore (mPTP), and strong alterations in the expression of mPTP regulators. Moreover, we also showed an enhanced effect of PK11195 and PPIX, on the parameters of the mPTP opening in rat liver mitochondria (RLM) isolated from ethanol-treated rats compared to the RLM from control rats. We suggest that the results of this study could help elucidate the mechanisms of chronic ethanol action on the mitochondria and contribute to the development of new therapeutic strategies for treating the effects of ethanol-related diseases.


2017 ◽  
Vol 6 (6) ◽  
pp. 822-830 ◽  
Author(s):  
Long Ma ◽  
Jun-Yi Liu ◽  
Jia-Xin Dong ◽  
Qi Xiao ◽  
Jie Zhao ◽  
...  

Toxicities and mechanisms of Pb2+ on isolated rat liver mitochondria.


2003 ◽  
Vol 285 (2) ◽  
pp. G274-G281 ◽  
Author(s):  
Thilo Hagen ◽  
Christopher J. Lagace ◽  
Josephine S. Modica-Napolitano ◽  
June R. Aprille

Mitochondrial permeability transition, due to opening of the permeability transition pore (PTP), is triggered by Ca2+ in conjunction with an inducing agent such as phosphate. However, incubation of rat liver mitochondria in the presence of low micromolar concentrations of Ca2+ and millimolar concentrations of phosphate is known to also cause net efflux of matrix adenine nucleotides via the ATP-Mg/Pi carrier. This raises the possibility that adenine nucleotide depletion through this mechanism contributes to mitochondrial permeability transition. Results of this study show that phosphate-induced opening of the mitochondrial PTP is, at least in part, secondary to depletion of the intramitochondrial adenine nucleotide content via the ATP-Mg/Pi carrier. Delaying net adenine nucleotide efflux from mitochondria also delays the onset of phosphate-induced PTP opening. Moreover, mitochondria that are depleted of matrix adenine nucleotides via the ATP-Mg/Pi carrier show highly increased susceptibility to swelling induced by high Ca2+ concentration, atractyloside, and the prooxidant tert-butylhydroperoxide. Thus the ATPMg/Pi carrier, by regulating the matrix adenine nucleotide content, can modulate the sensitivity of rat liver mitochondria to undergo permeability transition. This has important implications for hepatocytes under cellular conditions in which the intramitochondrial adenine nucleotide pool size is depleted, such as in hypoxia or ischemia, or during reperfusion when the mitochondria are exposed to increased oxidative stress.


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