School of Basic Medical Sciences, Nanjing Medical University, Nanjing, 211166, China.
Department of Pathology, The Affiliated Jiangning Hospital of Nanjing Medical University, Nanjing, 211100, China.
J Neuroimmune Pharmacol. 2024 Aug 28;19(1):48. doi: 10.1007/s11481-024-10138-6.
Traumatic brain injury (TBI) is a leading cause of death and disability worldwide. Microglial activation and neuroinflammation are key cellular events that determine the outcome of TBI, especially neuronal and cognitive function. Studies have suggested that the metabolic characteristics of microglia dictate their inflammatory response. The pyruvate kinase isoform M2 (PKM2), a key glycolytic enzyme, is involved in the regulation of various cellular metabolic processes, including mitochondrial metabolism. This suggests that PKM2 may also participate in the regulation of microglial activation during TBI. Therefore, the present study aimed to evaluate the role of PKM2 in regulating microglial activation and neuroinflammation and its effects on cognitive function following TBI. A controlled cortical impact (CCI) mouse model and inflammation-induced primary mouse microglial cells in vitro were used to investigate the potential effects of PKM2 inhibition and regulation. PKM2 was significantly increased during the acute and subacute phases of TBI and was predominantly detected in microglia rather than in neurons. Our results demonstrate that shikonin and TEPP-46 can inhibit microglial inflammation, improving mitochondria, improving mouse behavior, reducing brain defect volume, and alleviating pathological changes after TBI. There is a difference in the intervention of shikonin and TEPP-46 on PKM2. Shikonin directly inhibits General PKM2; TEPP-46 can promote the expression of PKM2 tetramer. In vitro experiments, TEPP-46 can promote the expression of PKM2 tetramer, enhance the interaction between PKM2 and MFN2, improve mitochondria, alleviate neuroinflammation. General inhibition and tetramerization activation of PKM2 attenuated cognitive function caused by TBI, whereas PKM2 tetramerization exhibited a better treatment effect. Our experiments demonstrated the non-metabolic role of PKM2 in the regulation of microglial activation following TBI. Both shikonin and TEPP-46 can inhibit pro-inflammatory factors, but only TEPP-46 can promote PKM2 tetramerization and upregulate the release of anti-inflammatory factors from microglia.
创伤性脑损伤（TBI）是全球范围内导致死亡和残疾的主要原因。小胶质细胞激活和神经炎症是决定 TBI 结局的关键细胞事件，特别是神经元和认知功能。研究表明，小胶质细胞的代谢特征决定了其炎症反应。丙酮酸激酶同工酶 M2（PKM2）是一种关键的糖酵解酶，参与调节各种细胞代谢过程，包括线粒体代谢。这表明 PKM2 也可能参与调节 TBI 中小胶质细胞的激活。因此，本研究旨在评估 PKM2 在调节小胶质细胞激活和神经炎症以及对 TBI 后认知功能的影响中的作用。使用控制皮质撞击（CCI）小鼠模型和体外炎症诱导的原代小鼠小胶质细胞来研究 PKM2 抑制和调节的潜在作用。在 TBI 的急性期和亚急性期，PKM2 显著增加，主要在小胶质细胞中检测到，而不是在神经元中。我们的结果表明，紫草素和 TEPP-46 可以抑制小胶质细胞炎症，改善线粒体，改善小鼠行为，减少脑损伤体积，并减轻 TBI 后的病理变化。紫草素和 TEPP-46 对 PKM2 的干预存在差异。紫草素直接抑制普通 PKM2；TEPP-46 可以促进 PKM2 四聚体的表达。在体外实验中，TEPP-46 可以促进 PKM2 四聚体的表达，增强 PKM2 与 MFN2 的相互作用，改善线粒体，减轻神经炎症。PKM2 的普遍抑制和四聚体激活减轻了 TBI 引起的认知功能障碍，而 PKM2 四聚体激活表现出更好的治疗效果。我们的实验证明了 PKM2 在 TBI 后调节小胶质细胞激活中的非代谢作用。紫草素和 TEPP-46 都可以抑制促炎因子，但只有 TEPP-46 可以促进 PKM2 四聚体形成并上调小胶质细胞中抗炎因子的释放。
