Sterile alpha and Toll/interleukin-1 receptor motif-containing 1 (SARM1) is a pro-degenerative molecule in Wallerian degeneration, which is mainly expressed in brain/neurons and colocalized with mitochondria and microtubules. The aim of this study was to determine the role of SARM1 in cerebral ischemia/reperfusion (I/R) injury and the underlying mechanisms. In vivo, a middle cerebral artery occlusion/reperfusion (MCAO/R) model in adult male Sprague Dawley rats (250–300 g) was established, and in vitro, cultured primary neurons were subjected to oxygen-glucose deprivation/reoxygenation (OGD/R) to imitate I/R injury. Overexpression lentiviruses encoding wild-type SARM1 and SARM1 with serine 548 alanine mutation (S548A) were constructed and administered to rats by intra-penumbral injection. First, the potential role of SARM1 in cerebral I/R injury was confirmed by the increased protein levels of SARM1 within penumbra tissue, especially in neurons. Second, there was an increase in the phosphorylation ratio of p-SARM1(S548)/SARM1 at 2 h after MCAO/R. Third, on the basis of site-specific mutagenesis, we identified S548 as a key site for SARM1 phosphorylation in I/R conditions. Fourth, SARM1 (S548A) overexpression reduced infarct size, neuronal death, and neurobehavioral dysfunction, while wild-type SARM1 overexpression had the opposite effects. Finally, we found that SARM1 phosphorylation at the S548 site switched SARM1 function from promoting mitochondrial transport to inhibiting mitochondrial transport along axons after I/R injury. Restriction of SARM1 phosphorylation at S548 may be a promising intervention target for I/R injury; thus, exogenous administration of SARM1 (S548A) may be a novel strategy for improving neurological outcomes.

不育 alpha 和 Toll/interleukin-1 受体基序包含 1 (SARM1) 是沃勒变性中的促退行性分子，主要在脑/神经元中表达，并与线粒体和微管共定位。本研究的目的是确定 SARM1 在脑缺血/再灌注 (I/R) 损伤中的作用及其潜在机制。在体内，建立成年雄性 Sprague Dawley 大鼠（250-300 g）大脑中动脉闭塞/再灌注（MCAO/R）模型，并在体外对培养的原代神经元进行氧-葡萄糖剥夺/复氧（OGD/ R) 模拟 I/R 损伤。构建了编码野生型 SARM1 和具有丝氨酸 548 丙氨酸突变 (S548A) 的 SARM1 的过表达慢病毒，并通过半影内注射给予大鼠。第一的，SARM1 在脑 I/R 损伤中的潜在作用通过半暗带组织中 SARM1 蛋白水平的增加得到证实，尤其是在神经元中。其次，在 MCAO/R 后 2 小时，p-SARM1(S548)/SARM1 的磷酸化比率增加。第三，基于位点特异性诱变，我们将 S548 鉴定为 I/R 条件下 SARM1 磷酸化的关键位点。第四，SARM1 (S548A) 过表达减少了梗死面积、神经元死亡和神经行为功能障碍，而野生型 SARM1 过表达具有相反的效果。最后，我们发现 S548 位点的 SARM1 磷酸化将 SARM1 的功能从促进线粒体转运转变为抑制 I/R 损伤后沿轴突的线粒体转运。S548 处 SARM1 磷酸化的限制可能是 I/R 损伤的一个有希望的干预目标；因此，