Uncontrolled microglial activation contributes to the pathogenesis of various neurodegenerative diseases. Previous studies have shown that proinflammatory microglia are powered by glycolysis, which relays on high levels of glucose uptake. This study aimed to understand how glucose uptake is facilitated in active microglia and whether microglial activation can be controlled by restricting glucose uptake. Primary murine brain microglia, BV2 cells and the newly established microglial cell line B6M7 were treated with LPS (100 ng/ml) + IFNγ (100 ng/ml) or IL-4 (20 ng/ml) for 24 h. The expression of glucose transporters (GLUTs) was examined by PCR and Western blot. Glucose uptake by microglia was inhibited using the GLUT1-specific inhibitor STF31. The metabolic profiles were tested using the Glycolysis Stress Test and Mito Stress Test Kits using the Seahorse XFe96 Analyser. Inflammatory gene expression was examined by real-time RT-PCR and protein secretion by cytokine beads array. The effect of STF31 on microglial activation and neurodegeneraion was further tested in a mouse model of light-induced retinal degeneration. The mRNA and protein of GLUT1, 3, 4, 5, 6, 8, 9, 10, 12, and 13 were detected in microglia. The expression level of GLUT1 was the highest among all GLUTs detected. LPS + IFNγ treatment further increased GLUT1 expression. STF31 dose-dependently reduced glucose uptake and suppressed Extracellular Acidification Rate (ECAR) in naïve, M(LPS + IFNγ) and M(IL-4) microglia. The treatment also prevented the upregulation of inflammatory cytokines including TNFα, IL-1β, IL-6, and CCL2 in M(LPS + IFNγ) microglia. Interestingly, the Oxygen Consumption Rates (OCR) was increased in M(LPS + IFNγ) microglia but reduced in M(IL-4) microglia by STF31 treatment. Intraperitoneal injection of STF31 reduced light-induced microglial activation and retinal degeneration. Glucose uptake in microglia is facilitated predominately by GLUT1, particularly under inflammatory conditions. Targeting GLUT1 could be an effective approach to control neuroinflammation.

中文翻译：

---

葡萄糖转运蛋白1通过促进糖酵解来严格控制小胶质细胞的活化

不受控制的小胶质细胞活化促成各种神经退行性疾病的发病机理。先前的研究表明，促炎性小胶质细胞由糖酵解提供动力，糖酵解依赖于高水平的葡萄糖摄取。这项研究旨在了解如何在活跃的小胶质细胞中促进葡萄糖的摄取，以及是否可以通过限制葡萄糖的摄取来控制小胶质细胞的活化。用LPS（100 ng / ml）+IFNγ（100 ng / ml）或IL-4（20 ng / ml）处理原代鼠脑小胶质细胞，BV2细胞和新建立的小胶质细胞系B6M7 24小时。通过PCR和蛋白质印迹检查葡萄糖转运蛋白（GLUT）的表达。使用GLUT1特异性抑制剂STF31抑制小胶质细胞摄取葡萄糖。使用糖酵解压力测试和Mito压力测试套件使用Seahorse XFe96 Analyser测试代谢曲线。通过实时RT-PCR检查炎性基因表达，并通过细胞因子珠阵列检查蛋白质分泌。STF31对小胶质细胞活化和神经变性的作用在光诱导的视网膜变性的小鼠模型中进一步进行了测试。在小胶质细胞中检测到GLUT1、3、4、5、6、8、9、10、12和13的mRNA和蛋白质。在所有检测到的GLUT中，GLUT1的表达水平最高。LPS +IFNγ处理可进一步增加GLUT1表达。STF31剂量依赖性地降低了幼稚，M（LPS +IFNγ）和M（IL-4）小胶质细胞的葡萄糖摄取并抑制了细胞外酸化率（ECAR）。该治疗还防止了炎症细胞因子的上调，包括TNFα，IL-1β，IL-6，M（LPS +IFNγ）小胶质细胞中的CCL2和CCL2。有趣的是，通过STF31处理，M（LPS +IFNγ）小胶质细胞的耗氧率（OCR）增加，而M（IL-4）小胶质细胞的耗氧率降低。腹膜内注射STF31可减少光诱导的小胶质细胞活化和视网膜变性。GLUT1主要促进小胶质细胞的葡萄糖摄取，特别是在炎症条件下。靶向GLUT1可能是控制神经炎症的有效方法。