期刊
JOURNAL OF EXPERIMENTAL BIOLOGY
卷 225, 期 1, 页码 -出版社
COMPANY BIOLOGISTS LTD
DOI: 10.1242/jeb.243532
关键词
Reptiles; Mitochondrial bioenergetics; Negligible senescence; Aging; Cyclophilin D; Adenine nucleotide translocator
类别
资金
- Sao Paulo Research Foundation (Fundacao de Amparo a Pesquisa do Estado de Sao Paulo, FAPESP) [2017/05487-6, 2019/20855-7]
- FAPESP [2017/17728-8]
This study found that the retention capacity of tortoise liver mitochondria for Ca2+ is significantly higher than that of rats, which may be related to the limitations of ANT and cyclophilin D in tortoises. In addition, the rates of H2O2 release and glutathione redox status are similar between tortoises and rats.
The interaction between supraphysiological cytosolic Ca2+ levels and mitochondrial redox imbalance mediates the mitochondrial permeability transition (MPT). The 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 carbonada) with those in the rat as a reference standard. Mitochondrial Ca2+ retention capacity, a quantitative measure of MPT sensitivity, was remarkably higher in tortoises than in 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.
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