Department of Neurology, Hebei General Hospital, No.348 Heping West Road, Shijiazhuang, 050051, Hebei, P. R. China.
Neuromolecular Med. 2022 Sep;24(3):299-310. doi: 10.1007/s12017-021-08688-6. Epub 2021 Oct 27.
Previous studies have demonstrated that increased O-linked N-acetylglucosamine (O-GlcNAc) level could promote cell survival following environmental stresses. This study aimed to explore the role of O-GlcNAc transferase (OGT) during cerebral ischemia/reperfusion (I/R) injury. The mouse model with cerebral I/R injury was induced by middle cerebral artery occlusion/reperfusion (MCAO/R). The expression of ogt in brain tissues was detected by qRT-PCR, Western blot, and immunohistochemistry (IHC) staining assay. Neurological deficit was evaluated using a modified scoring system. The infarct volume was assessed by TTC staining assay. Neuronal apoptosis in brain tissues was evaluated by TUNEL staining assay. The level of cleaved caspase-3 in brain tissues was detected by Western blot and IHC staining assay. The expression of critical proteins involved in mitochondrial fission, including OPA1, Mfn1, and Mfn2, as well as Mff and Drp1 was detected by Western blot and IHC, respectively. The expression of ogt during cerebral I/R injury was significantly upregulated. Ogt knockdown significantly increased neurological score and infarct volume in I/R-induced mice. Meanwhile, ogt knockdown significantly enhanced neuronal apoptosis and cleaved caspase-3 level in brain tissues of I/R-induced mice. In addition, ogt knockdown markedly decreased serine 637 phosphorylation level of mitochondrial fission protein dynamin-related protein 1 (Drp1) and promoted Drp1 translocation from the cytosol to the mitochondria. Moreover, the specific Drp1 inhibitor mdivi-1 effectively attenuated ogt knockdown-induced brain injury of I/R-stimulated mice in vivo. Our study revealed that OGT protects against cerebral I/R injury by inhibiting the function of Drp1 in mice, suggesting that ogt may be a potential therapeutic target for cerebral I/R injury.
先前的研究表明，O-连接的 N-乙酰氨基葡萄糖（O-GlcNAc）水平的升高可促进环境应激后的细胞存活。本研究旨在探讨 O-连接糖基化转移酶（OGT）在脑缺血/再灌注（I/R）损伤中的作用。通过大脑中动脉闭塞/再灌注（MCAO/R）诱导小鼠脑 I/R 损伤模型。通过 qRT-PCR、Western blot 和免疫组织化学（IHC）染色检测脑组织中 ogt 的表达。采用改良评分系统评估神经功能缺损。采用 TTC 染色法评估梗死体积。采用 TUNEL 染色法评估脑组织中的神经细胞凋亡。采用 Western blot 和 IHC 染色法检测脑组织中裂解的 caspase-3 水平。通过 Western blot 和 IHC 分别检测参与线粒体分裂的关键蛋白，包括 OPA1、Mfn1 和 Mfn2，以及 Mff 和 Drp1 的表达。脑 I/R 损伤过程中 ogt 的表达明显上调。OGT 敲低可显著增加 I/R 诱导的小鼠的神经功能评分和梗死体积。同时，OGT 敲低可显著增强脑 I/R 诱导的小鼠脑组织中的神经细胞凋亡和裂解的 caspase-3 水平。此外，OGT 敲低可显著降低线粒体分裂蛋白动力相关蛋白 1（Drp1）的丝氨酸 637 磷酸化水平，并促进 Drp1 从细胞质向线粒体的易位。此外，特异性 Drp1 抑制剂 mdivi-1 可有效减轻体内 I/R 刺激的小鼠中 ogt 敲低诱导的脑损伤。我们的研究表明，OGT 通过抑制 Drp1 在小鼠中的功能来保护大脑免受 I/R 损伤，这表明 ogt 可能是脑 I/R 损伤的潜在治疗靶点。
