Huang Z W, Liu Y Y, Chen X M, Yu C L, He H Y, Deng Y H
Department of basic medicine, Medical School, Kunming University of Science and Technology, Kunming, 650093 China.
Anning First People's Hospital Affiliated to Kunming University of Science and Technology, Kunming, 650093 China.
Acta Naturae. 2023 Jul-Sep;15(3):91-99. doi: 10.32607/actanaturae.11830.
Neuronal CX3CL1 suppressed microglial inflammation by binding to its receptor CX3CR1 expressed on microglia. Neuronal autophagy was prominently activated by cerebral ischemia, whereas CX3CL1 expression in autophagic neurons was conversely down-regulated to exacerbate microglial inflammation. Accordingly, this study was meant to investigate whether ischemia-activated microglial inflammation could be repressed by promoting CX3CL1 expression via the attenuation of neuronal autophagy. Immunofluorescence showed that autophagy predominantly occurred in neurons but barely in microglia. Western blot and immunofluorescence demonstrated that attenuating HT22 autophagy significantly increased its CX3CL1 expression and subsequently mitigated the BV2-mediated inflammatory responses, as indicated by decreased inflammatory factors of NF-κB-p65, IL-6, IL-1β, TNF-α, and PGE2. Meanwhile, CCK-8, Nissl staining, and FJC staining showed that an OGD (Oxygen-glycogen deprivation)-created neuronal injury was greatly alleviated by CX3CL1-suppressed microglial inflammation. Contrarily, elevating HT22 autophagy markedly decreased its CX3CL1 expression, which consequently worsened microglial inflammation and the neuronal injury. Our data suggests that attenuating neuronal autophagy may be an effective method to alleviate a microglial inflammatory injury after an ischemic stroke.
神经元CX3CL1通过与小胶质细胞上表达的受体CX3CR1结合来抑制小胶质细胞炎症。脑缺血显著激活神经元自噬，而自噬神经元中CX3CL1的表达则相反下调，从而加剧小胶质细胞炎症。因此，本研究旨在探讨通过减弱神经元自噬来促进CX3CL1表达是否可以抑制缺血激活的小胶质细胞炎症。免疫荧光显示自噬主要发生在神经元中，而在小胶质细胞中几乎不发生。蛋白质免疫印迹和免疫荧光表明，减弱HT22细胞的自噬显著增加其CX3CL1表达，随后减轻BV2介导的炎症反应，表现为NF-κB-p65、IL-6、IL-1β、TNF-α和PGE2等炎症因子减少。同时，CCK-8、尼氏染色和FJC染色显示，CX3CL1抑制的小胶质细胞炎症极大地减轻了氧糖剥夺（OGD）造成的神经元损伤。相反，增强HT22细胞的自噬显著降低其CX3CL1表达，从而加剧小胶质细胞炎症和神经元损伤。我们的数据表明，减弱神经元自噬可能是减轻缺血性中风后小胶质细胞炎症损伤的有效方法。
