Li Yin, Zhou Hang, He Xuchao, Jin Lingji, Zhu Yuhan, Hu Libin, Feng Majing, Zhu Jun, Wang Liang, Zheng Yonghe, Li Shiwei, Yan Zhiyuan, Cen Peili, Hu Junwen, Chen Zihang, Yu Xiaobo, Fu Xiongjie, Xu Chaoran, Cao Shenglong, Cao Yang, Chen Gao, Wang Lin
Department of Neurosurgery & Key Laboratory of Precise Treatment and Clinical Translational Research of Neurological Diseases, Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, China.
School of Medicine, Zhejiang University, Hangzhou, China.
J Adv Res. 2024 Aug 13. doi: 10.1016/j.jare.2024.08.016.
Intracerebral haemorrhage (ICH) is a devastating disease that leads to severe neurological deficits. Microglia are the first line of defence in the brain and play a crucial role in neurological recovery after ICH, whose activities are primarily driven by glucose metabolism. However, little is known regarding the status of glucose metabolism in microglia and its interactions with inflammatory responses after ICH.
This study investigated microglial glycolysis and its mechanistic effects on microglial inflammation after ICH.
We explored the status of glucose metabolism in the ipsilateral region and in fluorescence-activated-cell-sorting-isolated (FACS-isolated) microglia via 2-deoxy-[F]fluoro-D-glucose positron emission tomography (FDG-PET) analyses and gamma emission, respectively. Energy-related targeted metabolomics, along with C-glucose isotope tracing, was utilised to analyse glycolytic products in microglia. Mitochondrial membrane potential and mitochondrial reactive oxygen species (MitoROS) accumulation was assessed by flow cytometry. Behavioural, western blotting, gene regulation, and enzymatic activity analyses were conducted with a focus on microglia.
Neurological dysfunction was strongly correlated with decreased FDG-PET signals in the perihaematomal region, where microglial uptake of FDG was reduced. The decreased quantity of glucose-6-phosphate (G-6-P) in microglia was attributed to the downregulation of glucose transporter 1 (GLUT1) and hexokinase 2 (HK2). Enhanced inflammatory responses were driven by HK2 suppression via decreased mitochondrial membrane potential, which could be rescued by MitoROS scavengers. HK inhibitors aggravated neurological injury by suppressing FDG uptake and enhancing microglial inflammation in ICH mice.
These findings indicate an unexpected metabolic status in pro-inflammatory microglia after ICH, consisting of glycolysis impairment caused by the downregulation of GLUT1 and HK2. Additionally, HK2 suppression promotes inflammatory responses by disrupting mitochondrial function, providing insight into the mechanisms by which inflammation may be facilitated after ICH and indicating that metabolic enzymes as potential targets for ICH treatment.
脑出血（ICH）是一种破坏性疾病，会导致严重的神经功能缺损。小胶质细胞是大脑的第一道防线，在脑出血后的神经恢复中起关键作用，其活动主要由葡萄糖代谢驱动。然而，关于脑出血后小胶质细胞中葡萄糖代谢的状态及其与炎症反应的相互作用，我们知之甚少。
本研究调查了脑出血后小胶质细胞的糖酵解及其对小胶质细胞炎症的机制性影响。
我们分别通过2-脱氧-[F]氟-D-葡萄糖正电子发射断层扫描（FDG-PET）分析和γ发射，探索同侧区域以及荧光激活细胞分选分离（FACS分离）的小胶质细胞中的葡萄糖代谢状态。利用能量相关的靶向代谢组学以及C-葡萄糖同位素示踪，分析小胶质细胞中的糖酵解产物。通过流式细胞术评估线粒体膜电位和线粒体活性氧（MitoROS）积累。重点针对小胶质细胞进行行为、蛋白质印迹、基因调控和酶活性分析。
神经功能障碍与血肿周围区域FDG-PET信号降低密切相关，该区域小胶质细胞对FDG的摄取减少。小胶质细胞中葡萄糖-6-磷酸（G-6-P）数量的减少归因于葡萄糖转运蛋白1（GLUT1）和己糖激酶2（HK2）的下调。HK2抑制通过降低线粒体膜电位驱动炎症反应增强，而线粒体活性氧清除剂可挽救这种情况。HK抑制剂通过抑制ICH小鼠的FDG摄取和增强小胶质细胞炎症，加重神经损伤。
这些发现表明脑出血后促炎性小胶质细胞存在意外的代谢状态，包括由GLUT1和HK2下调引起的糖酵解受损。此外，HK2抑制通过破坏线粒体功能促进炎症反应，为脑出血后炎症可能被促进的机制提供了见解，并表明代谢酶是脑出血治疗的潜在靶点。
