Research ArticleIschemia Injury induces mPTP opening by reducing Sirt3
Introduction
Stroke is one of the leading causes of death and physical disability worldwide (Panel et al., 2018). About 80% of strokes are ischemic stroke (Lapchak and Zhang, 2017). Mitochondria regulate cell energy homeostasis and cell death. Mitochondrial dysfunction is one of the hallmarks in neuronal death through calcium overload and mitochondrial permeability transition pore (mPTP) opening (Sims and Muyderman, 2010). mPTP opening is critical to mitochondrial apoptosis during ischemic injury (Chanoit et al., 2011, Kinnally et al., 2011). mPTP is composed of Cyclophilin D (CypD) in the mitochondrial matrix, voltage-dependent anion channel 1 (VDAC1) across the outer mitochondrial membrane, and adenine nucleotide translocator 1 (ANT1) in the inner mitochondrial membrane (Halestrap and Davidson, 1990, Szabó et al., 1993, Baines et al., 2005, Kalani et al., 2018).
There are seven mammalian sirtuins (Sirt1-7). Sirt3, 4, and 5 are mitochondrial sirtuins. Sirt3 plays an important role in regulating mitochondrial metabolism, such as amino acid metabolism, the urea cycle, the tricarboxylic acid cycle, fatty acid oxidation, oxidative phosphorylation and mitochondrial dynamics(Samant et al., 2014, Papa and Germain, 2017). Sirt3 is a mitochondrial deacetylase known to play a major role in stress resistance and in cell death (Castillo et al., 2019, Li et al., 2019a, Pillai et al., 2010, Sundaresan et al., 2009, Wu et al., 2020). Sirt3 inhibited mPTP opening in Huntington’s disease (Cheng et al., 2016), amyloid-β related oxidative stress injury (Jiang et al., 2017a), doxorubicin-induced brain cortex and cerebellum mitochondrial toxicity (Marques-Aleixo et al., 2016), seizure (Cheng et al., 2016, Amigo et al., 2017) and sepsis-associated encephalopathy (Jiang et al., 2017b). Sirt3 protected against neuronal ischemia by inhibiting apoptosis (Feng et al., 2018, Zhao et al., 2019). Our previous studies found that Sirt3 activate superoxide dismutase 2 and forkhead box O3a to reduce cellular reactive oxygen species (ROS) levels (Yin et al., 2015). However, it is unclear if there is a relationship between mPTP opening and Sirt3 in ischemic stroke. In this study, we hypothesize that ischemia injury induces mPTP opening by reducing Sirt3. To investigate the expression of Sirt3 and mPTP related proteins in ischemic stroke, we established the MCAO mice model. To explore the relationship between Sirt3 and mPTP opening, we overexpressed Sirt3 to measure mPTP and apoptosis proteins under ischemic condition in vitro in HT22 cells.
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Animals
C57BL/6 male mice (7–8 weeks, 22–24 g) were obtained from the SPF Biotechnology Co. Ltd. (Beijing, China). All mice were housed in a temperature and humidity-controlled vivarium, with food and water ad libitum. Approval was granted by the Ethics Committee of Beijing Tiantan Hospital. A total of twenty-three mice were used in this study, two animals died during MCAO operation and after ischemia. Three animals were excluded according to the neurologic function. Efforts were performed to minimize
Changes in protein levels of Sirt3, VDAC1 and ANT1 in the penumbra area.
Cerebral blood flow (CBF) was assessed by laser speckle contrast imaging (LSCI) (RWD Life Science Co., Ltd, Shenzhen, China). Blood perfusion was monitored by LSCI at the end of 60-minute occlusion (Fig. 1A, B). It showed that the CBF at the ischemic hemisphere was decreased about 58.86% compared to the contralateral hemisphere (p < 0.001). In the penumbra area, transmission electron microscopy showed that mitochondria of neurons were swelling and formed vacuolation. Both inner and outer
Discussion
Stroke has multifaceted pathology. Mitochondrial pathways are involved in the pathophysiology of stroke, however the role of Sirt3 in ischemic stroke is unclear. Our previous studies have shown that Sirt3 activates superoxide dismutase 2 and forkhead box O3a to reduce cellular ROS levels (Yin et al., 2015). The protective effect of Sirt3 was also demonstrated in oxygen and glucose deprivation (OGD)-induced neuronal injury via promoting autophagy through the AMPK-mTOR pathway in vitro (Dai et
Funding
This work was supported by Beijing Science and Technology Plan / Brain Science and Research North Science Center Project (Z181100001518005) and the Strategic Priority Research Program of the Chinese Academy of Sciences (XDB39000000).
Ethical approval
All animal experiments were conducted according to the authorization from the Ethics Committee of Beijing Tiantan Hospital.
Declaration of Competing Interest
The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
Acknowledgements
The authors would like to thank Qi Zhang and Cuiping Zhang for their help in transmission electron microscope.
References (47)
- et al.
Mitochondrial SIRT3 mediates adaptive responses of neurons to exercise and metabolic and excitatory challenges
Cell Metab
(2016) - et al.
Sirt3 confers protection against neuronal ischemia by inducing autophagy: Involvement of the AMPK-mTOR pathway
Free Radic Biol Med
(2017) - et al.
Icariside II alleviates oxygen-glucose deprivation and reoxygenation-induced PC12 cell oxidative injury by activating Nrf2/SIRT3 signaling pathway
Biomed Pharmacother
(2018) - et al.
Liproxstatin-1 protects the mouse myocardium against ischemia/reperfusion injury by decreasing VDAC1 levels and restoring GPX4 levels
Biochem Biophys Res Commun
(2019) - et al.
Mitochondrial permeability transition pore: a potential drug target for neurodegeneration
Drug Discov Today
(2018) - et al.
Is mPTP the gatekeeper for necrosis, apoptosis, or both?
BBA
(2011) - et al.
Physical exercise mitigates doxorubicin-induced brain cortex and cerebellum mitochondrial alterations and cellular quality control signaling
Mitochondrion
(2016) - et al.
Exogenous NAD blocks cardiac hypertrophic response via activation of the SIRT3-LKB1-AMP-activated kinase pathway
J Biol Chem
(2010) - et al.
Mitochondria, oxidative metabolism and cell death in stroke
BBA
(2010) - et al.
The mitochondrial permeability transition pore may comprise VDAC molecules. II. The electrophysiological properties of VDAC are compatible with those of the mitochondrial megachannel
FEBS Lett
(1993)
Ca(2+)-mediated regulation of VDAC1 expression levels is associated with cell death induction
BBA
Polydatin protects against lipopolysaccharide-induced endothelial barrier disruption via SIRT3 activation
Lab Invest
Genipin protects against cerebral ischemia-reperfusion injury by regulating the UCP2-SIRT3 signaling pathway
Eur J Pharmacol
Caloric restriction increases brain mitochondrial calcium retention capacity and protects against excitotoxicity
Aging Cell
Core and penumbral nitric oxide synthase activity during cerebral ischemia and reperfusion in the rat pup
Pediatr Res
Vdac1 downregulation causes mitochondrial disintegration leading to hippocampal neurodegeneration in scopolamine-induced amnesic mice
Mol Neurobiol
Loss of cyclophilin D reveals a critical role for mitochondrial permeability transition in cell death
Nature
Sirtuin 3 promotes microglia migration by upregulating CX3CR1
Cell Adhes Migr
Mitochondrial hyperacetylation in the failing hearts of obese patients mediated partly by a reduction in SIRT3: the involvement of the mitochondrial permeability transition pore
Cell Physiol Biochem
Inhibition of phosphodiesterases leads to prevention of the mitochondrial permeability transition pore opening and reperfusion injury in cardiac H9c2 cells
Cardiovasc Drugs Ther
Fundamental mechanisms of regulated cell death and implications for heart disease
Physiol Rev
Mitochondria: master regulators of danger signalling
Nat Rev Mol Cell Biol
Inhibition of Ca2(+)-induced large-amplitude swelling of liver and heart mitochondria by cyclosporin is probably caused by the inhibitor binding to mitochondrial-matrix peptidyl-prolyl cis-trans isomerase and preventing it interacting with the adenine nucleotide translocase
Biochem J
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