线粒体自噬通过清除受损线粒体，保护脑缺血后的神经元。PINK1(PTEN-induced putative kinase 1)/Parkin通路通过催化底物的泛素化，介导线粒体自噬。我们前期研究发现，予8%O2的低氧后处理可激活短暂全脑缺血后海马CA1区PINK1/Parkin通路，促进线粒体自噬而起神经保护作用。已有研究证实TANK结合激酶1（TBK1）的激活参与调控线粒体自噬。然而，PINK1/Parkin通路能否调控TBK1的活化，介导脑缺血耐受？迄今未见报道。为此，我们提出假设，低氧后处理激活脑缺血后CA1区PINK1/Parkin通路，除促进线粒体泛素化外，还调控TBK1的翻译后修饰并使其激活，从而使p62磷酸化，促进自噬小体识别与吞噬受损线粒体，发挥神经保护作用。本项目将揭示PINK1/Parkin通路依赖的线粒体自噬在脑缺血耐受中的新机制，为干预脑缺血损伤提供潜在靶点。

Mitophagy plays an essential role in protecting neurons against cerebral ischemia/reperfusion injury by selectively removing impaired or dysfunctional mitochondria, thereby maintaining mitochondrial homeostasis. In general, the mechanisms of mitophagy in mammalian cells involve in Parkin-dependent and Parkin-independent pathways. Our previous studies demonstrated that hypoxic postconditioning (HPC) with 8% O2 activated the PTEN-induced putative kinase 1(PINK1)/Parkin pathway, upregulated the level of mitochondrial ubiquitination and promoted the clearance of damaged mitochondria in the hippocampal CA1 subregion after transient global cerebral ischemia (tGCI). However, the underlying molecular mechanisms of PINK1/Parkin-mediated mitophagy in ischemic tolerance against tGCI need to be further elucidated. Recent reports have showed that PINK1/Parkin pathway mediated mitophagy through ubiquitylating the substrates. Moreover, the K63-linked polyubiquitination of TBK1 (TANK-binding kinase 1) contributed to its activation. Intriguingly, the activation of TBK1, mediated by PINK1/Parkin pathway, was involved in the regulation of mitophagy. However, the roles of mitophagy induced by PINK1/Parkin-mediated ubiquitination of TBK1 in cerebral ischemic tolerance against tGCI and the underlying molecular mechanisms have not been reported. Therefore, we hypothesize that HPC can offer neuroprotection against tGCI by promoting PINK1/Parkin-dependent mitochondrial ubiquitination in CA1. Furthermore, HPC induces TBK1 activation mediated by PINK1/Parkin-dependent K63-linked polyubiquitination, thereby phosphorylating p62 and regulating the autophagosomal engulfment of ubiquitinated mitochondria and subsequently promoting mitochondrial clearance by autophagy after tGCI. In this project, we will provide new insights into the molecular mechanisms underlying PINK1/Parkin-dependent mitophagy and assert that mitophagy may play a part in ischemic tolerance against tGCI-induced injury. Therefore, these findings bring forth the possibility that the targeted manipulation of mitophagy may be of clinical significance for the novel therapeutic interventions to cerebral ischemic injury.