Department of Neurology, the First Affiliated Hospital of Chongqing Medical University, 1 Youyi Road, Yuzhong District, Chongqing, 400016, China.
Mol Biol Rep. 2023 Apr;50(4):3317-3327. doi: 10.1007/s11033-022-08167-6. Epub 2023 Feb 1.
Cerebral ischemic injury leads to over-activation of microglia, which release pro-inflammatory factors that deteriorate neurological function during the acute phase of stroke. Thus, inhibiting microglial over-activation is crucial for reducing ischemic injury. Sirtuin 1 (Sirt1) has been shown to play a critical role in stroke, neurodegenerative diseases and aging. However, the effect of Sirt1 on the regulation of microglial activation following cerebral ischemic injury, as well as the underlying mechanism, remain unknown. Therefore, the purpose of the present study is to mainly investigate the effect of Sirt1 on oxygen-glucose deprivation/reoxygenation (OGD/R)-treated N9 microglia following treatment with the Sirt1 agonists resveratrol and SRT1720 and the Sirt1 antagonist sirtinol.
Cell viability, Apoptosis, activation and inflammatory responses of microglia, expressions and activity of Shh signaling pathway proteins were detected by Cell Counting Kit 8, Flow Cytometry, immunocytochemistry, ELISA, and Western blotting, respectively.
The results demonstrated that treatment with resveratrol or SRT1720 could inhibit the activation of microglia and inflammation during OGD/R. Moreover, these treatments also led to the translocation of the GLI family zinc finger-1 (Gli-1) protein from the cytoplasm to the nucleus and upregulated the expression of Sonic hedgehog (Shh), Patched homolog-1 (Ptc-1), smoothened frizzled class receptor and Gli-1. By contrast, the inhibition of Sirt1 using sirtinol had the opposite effect.
These findings suggested that Sirt1 may regulate microglial activation and inflammation by targeting the Shh/Gli-1 signaling pathway following OGD/R injury. Schematic representation of Sirt1 regulating the microglial activation and inflammation following oxygen-glucose deprivation/reoxygenation injury via mediation of Shh/Gli-1 signaling pathway.
脑缺血损伤导致小胶质细胞过度激活，释放促炎因子，在中风急性期恶化神经功能。因此，抑制小胶质细胞过度激活对于减少缺血性损伤至关重要。Sirtuin 1（Sirt1）已被证明在中风、神经退行性疾病和衰老中发挥关键作用。然而，Sirt1 对脑缺血损伤后小胶质细胞激活的调节作用及其潜在机制尚不清楚。因此，本研究的主要目的是研究 Sirt1 激动剂白藜芦醇和 SRT1720 以及 Sirt1 拮抗剂 sirtinol 处理后对氧葡萄糖剥夺/复氧（OGD/R）处理的 N9 小胶质细胞的影响。
通过细胞计数试剂盒 8、流式细胞术、免疫细胞化学、酶联免疫吸附试验和 Western blot 分别检测小胶质细胞活力、细胞凋亡、激活和炎症反应，Shh 信号通路蛋白的表达和活性。
结果表明，白藜芦醇或 SRT1720 处理可抑制 OGD/R 中小胶质细胞的激活和炎症。此外，这些处理还导致 GLI 家族锌指蛋白-1（Gli-1）蛋白从细胞质易位到细胞核，并上调 Sonic hedgehog（Shh）、Patched 同源物-1（Ptc-1）、平滑 Frizzled 类受体和 Gli-1 的表达。相比之下，使用 sirtinol 抑制 Sirt1 则产生相反的效果。
这些发现表明，Sirt1 可能通过靶向 OGD/R 损伤后的 Shh/Gli-1 信号通路来调节小胶质细胞的激活和炎症。Sirt1 通过调节 Shh/Gli-1 信号通路调节氧葡萄糖剥夺/复氧损伤后小胶质细胞激活和炎症的示意图。
