Department of Neurobiology, Capital Medical University, #10 You An Men Wai Xi Tou Tiao, Fengtai District, Beijing, 100069, People's Republic of China.
Beijing Key Laboratory of Hypoxia Conditioning Translational Medicine, Beijing, 100053, China.
Transl Stroke Res. 2023 Oct;14(5):790-801. doi: 10.1007/s12975-022-01094-5. Epub 2022 Oct 10.
Neuron-specific conventional protein kinase C (cPKC)γ mediates cerebral hypoxic preconditioning (HPC). In parallel, autophagy plays a prosurvival role in ischemic preconditioning (IPC) against ischemic stroke. However, the effect of cPKCγ on autophagy in IPC still remains to be addressed. In this study, adult and postnatal 1-day-old C57BL/6 J wild-type (cPKCγ) and knockout (cPKCγ) mice were used to establish in vivo and in vitro IPC models. The results showed that IPC pretreatment alleviated neuronal damage caused by lethal ischemia, which could be suppressed by autophagy inhibitor 3-MA or bafilomycin A1. Meanwhile, cPKCγ knockout blocked IPC-induced neuroprotection, accompanied by significant increase of LC3-I to LC3-II conversion and Beclin 1 protein level, and a significant decrease in p62 protein level. Immunofluorescent staining results showed a decrease of LC3 puncta numbers in IPC-treated cPKCγ neurons with fatal ischemia, which was reversed in cPKCγ neurons. In addition, cPKCγ-modulated phosphorylation of mTOR at Ser 2448 and ULK1 at Ser 555, rather than p-Thr-172 AMPK, was detected in IPC-pretreated neurons upon lethal ischemic exposure. The present data demonstrated that cPKCγ-modulated autophagy via the mTOR-ULK1 pathway likely modulated IPC-induced neuroprotection.
神经元特异性经典蛋白激酶 C（cPKC）γ介导脑缺氧预处理（HPC）。与此同时，自噬在缺血预处理（IPC）中对缺血性中风起到了生存促进作用。然而，cPKCγ 对 IPC 中自噬的影响仍有待解决。在这项研究中，成年和新生 1 天的 C57BL/6J 野生型（cPKCγ）和敲除（cPKCγ）小鼠被用于建立体内和体外 IPC 模型。结果表明，IPC 预处理减轻了致死性缺血引起的神经元损伤，这种保护作用可以被自噬抑制剂 3-MA 或巴弗洛霉素 A1 抑制。同时，cPKCγ 敲除阻断了 IPC 诱导的神经保护作用，伴随着 LC3-I 向 LC3-II 转化和 Beclin 1 蛋白水平的显著增加，以及 p62 蛋白水平的显著降低。免疫荧光染色结果显示，在致死性缺血处理的 cPKCγ 神经元中，LC3 斑点数量减少，而在 cPKCγ 神经元中则相反。此外，在 IPC 预处理的神经元中，cPKCγ 调节的 mTOR 在 Ser 2448 和 ULK1 在 Ser 555 的磷酸化，而不是 p-Thr-172 AMPK，在受到致死性缺血暴露时被检测到。本研究数据表明，cPKCγ 通过 mTOR-ULK1 通路调节的自噬可能调节了 IPC 诱导的神经保护作用。
