Department of Pediatric Surgery, Affiliated Hospital of Nantong University, Nantong, 226001, Jiangsu, China.
Medical College of Nantong University, Nantong, 226001, Jiangsu, China.
Neurochem Res. 2019 Jul;44(7):1602-1612. doi: 10.1007/s11064-019-02784-7. Epub 2019 Mar 25.
Pyruvate Kinase isozymes M2 (PKM2) is a glycolytic enzyme involved in glycolysis that decarboxylates phosphoenolpyruvate to pyruvate and generates ATP. PKM2 also plays a significant role in tumor growth, in cell division, angiogenesis, apoptosis and metastasis. In this study, we have investigated the role of PKM2 in cortical neurons which suffered hypoxic-ischemic encephalopathy (HIE) in newborn rats. Immunohistochemistry and Western blot analysis revealed the protein expression of PKM2 peaking at 24 h after HIE. Double immunofluorescence labeling showed that PKM2 was mainly located in the neurons of the ipsilateral cerebral cortex, not in astrocytes or microglia. The increased level of active caspase-3 and the decreased level of phosphorylated AKT (p-AKT) were consistent with the PKM2 expression. TUNEL staining assay showed that PKM2 may participate in neuronal apoptosis in the rat ipsilateral cerebral cortex. Silencing of PKM2 in primary cultures of cortical neurons using a specific siRNA reduced the expression of active caspase-3 and upregulated p-AKT expression. Taken together, the results indicate that PKM2 may be involved in neuronal apoptosis after HIE by a mechanism dependent on the inactivation of p-AKT.
丙酮酸激酶同工酶 M2（PKM2）是一种参与糖酵解的糖酵解酶，它将磷酸烯醇丙酮酸脱羧生成丙酮酸并产生 ATP。PKM2 还在肿瘤生长、细胞分裂、血管生成、细胞凋亡和转移中发挥重要作用。在这项研究中，我们研究了 PKM2 在新生大鼠缺氧缺血性脑病（HIE）皮质神经元中的作用。免疫组织化学和 Western blot 分析显示，PKM2 的蛋白表达在 HIE 后 24 小时达到峰值。双重免疫荧光标记显示，PKM2 主要位于对侧大脑皮质的神经元中，而不在星形胶质细胞或小胶质细胞中。活性 caspase-3 的增加水平和磷酸化 AKT（p-AKT）的减少水平与 PKM2 的表达一致。TUNEL 染色实验表明，PKM2 可能参与了大鼠对侧大脑皮质神经元的凋亡。用特异性 siRNA 沉默原代皮质神经元中的 PKM2，可降低活性 caspase-3 的表达并上调 p-AKT 的表达。综上所述，这些结果表明，PKM2 可能通过依赖于 p-AKT 失活的机制参与 HIE 后的神经元凋亡。
