Objectives: Cerebral ischemia-reperfusion (I/R) injury is the leading cause of ischemic stroke. Pyruvate Kinase isozymes M2 (PKM2), as a critical glycolytic enzyme during glycolysis, is involved in neuronal apoptosis in rats with hypoxic-ischemic encephalopathy. This study focused on functional investigation and potential molecular mechanism toward PKM2 in cerebral I/R injury. Methods: Cerebral I/R injury model was established by middle cerebral artery occlusion (MCAO) in vivo or oxygen-glucose deprivation and reoxygenation (OGD/R) in vitro. qRT-PCR and Western blot were used to detect the expression of PKM2 in I/R injury models. The effects of PKM2 on I/R injury were determined via triphenyl tetrazolium chloride staining and evaluation of neurological deficits. Cell Counting Kit-8 was employed to detect cell viability, and ELISA was conducted to detect pro-inflammatory cytokines. The underlying mechanism involved in regulation of PKM2 on I/R injury was investigated via ELISA and Western blot. Results: PKM2 was upregulated after cerebral I/R injury. Knockdown of PKM2 alleviated MCAO-induced infarction and neurological dysfunction. Moreover, PKM2 knockdown also alleviated OGD/R-induced neuronal cell injury and inflammatory response. Mechanistically, PKM2 knockdown-induced neuroprotection was accompanied by inhibition of high-mobility group box 1 (HMGB1), reflected by inactivation of TLR4/MyD88 (myeloid differentiation factor 88)/TRAF6 (TNF receptor-associated factor 6) signaling pathway. Conclusions: Knockdown of PKM2 attenuated cerebral I/R injury through HMGB1-mediated TLR4/MyD88/TRAF6 expression change, providing a potential target for cerebral I/R injury treatment.
Neuroimmunomodulation

中文翻译：

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PKM2 通过 TLR4/MyD88/TRAF6 信号通路加重脑缺血再灌注诱导的神经炎症

目的：脑缺血再灌注（I/R）损伤是缺血性卒中的主要原因。丙酮酸激酶同工酶 M2 (PKM2) 作为糖酵解过程中的关键糖酵解酶，参与缺氧缺血性脑病大鼠的神经元凋亡。本研究的重点是脑 I/R 损伤中 PKM2 的功能研究和潜在分子机制。方法：通过体内大脑中动脉闭塞(MCAO)或体外氧-葡萄糖剥夺再氧合(OGD/R)建立脑I/R损伤模型。qRT-PCR和Western印迹用于检测PKM2在I/R损伤模型中的表达。PKM2 对 I/R 损伤的影响通过氯化三苯基四唑染色和神经功能缺损评估来确定。Cell Counting Kit-8用于检测细胞活力，ELISA检测促炎细胞因子。通过 ELISA 和蛋白质印迹研究了 PKM2 对 I/R 损伤的调节所涉及的潜在机制。结果：PKM2 在脑 I/R 损伤后上调。敲低 PKM2 可减轻 MCAO 诱导的梗死和神经功能障碍。此外，PKM2 敲低还减轻了 OGD/R 诱导的神经元细胞损伤和炎症反应。从机制上讲，PKM2 敲低诱导的神经保护伴随着高迁移率组框 1 (HMGB1) 的抑制，这反映在 TLR4/MyD88（骨髓分化因子 88）/TRAF6（TNF 受体相关因子 6）信号通路的失活。结论：敲低 PKM2 通过 HMGB1 介导的 TLR4/MyD88/TRAF6 表达变化减轻脑 I/R 损伤，为脑 I/R 损伤治疗提供潜在靶点。
神经免疫调节