Guo Jingjing, Li Yun, Ma Kun, Su Guohai
Jinan Central Hospital, Cheeloo College of Medicine, Shandong University, Jinan, China.
Department of General Medicine, Central Hospital Affiliated to Shandong First Medical University, Jinan, China.
Front Cell Neurosci. 2025 Feb 20;19:1546848. doi: 10.3389/fncel.2025.1546848. eCollection 2025.
Autophagy, a regulator of inflammation, has been implicated in various central nervous system pathologies. Despite this, the role and mechanisms of autophagy in lipopolysaccharide (LPS)-induced neuroinflammation are not clear. This study investigated whether autophagy can play a neuroprotective role in LPS-induced neuroinflammation.
Primary microglial cells and male C57BL/6 J mice were treated with LPS, autophagy inhibitors (3-methyladenine, 3-MA), or autophagy activators (rapamycin). Cell viability, NF-κB pathway activation, pro-inflammatory cytokine expression, M1 polarization, autophagy markers, and neuronal damage were evaluated via various techniques including CCK-8 assay, Western blot analysis, ELISA, immunohistochemistry, and histological staining.
LPS (1 μg/mL) effectively inhibited cell viability, stimulated the expression of IκB-α and NF-κB, and simultaneously suppressed autophagy protein expression. The pro-inflammatory cytokines IL-1β and IL-6 showed a significant increase. Contrary to the effect of 3-MA, the rapamycin treatment inhibited the polarization of microglia cells to the M1 type in the various groups of microglia cells after LPS stimulation. This was evidenced by decreased expression of cytokines IL-1β, IL-6, and CD86, and increased expression of Arg-1, IL-10, and CD206. experiments found that mice with injections of LPS and 3-MA in the lateral ventricle showed significantly increased expression of IκB-α and NF-κB in brain tissues, elevated levels of pro-inflammatory cytokines, decreased autophagy levels, and increased necrotic neurons. There was increased aggregation of microglia cells and increased neuronophagocytosis. Conversely, mice injected with rapamycin showed enhanced neuronal cell autophagy, decreased expression of pro-inflammatory cytokines and apoptosis, and reduced neuronophagocytosis.
Enhancing autophagy can effectively mitigate LPS-induced neuroinflammation by inhibiting microglial M1 polarization and neuronophagocytosis, thereby protecting neuronal integrity. These findings suggest potential therapeutic strategies targeting autophagy in neuroinflammatory conditions.
自噬作为炎症的调节因子，已被证实与多种中枢神经系统疾病有关。尽管如此，自噬在脂多糖（LPS）诱导的神经炎症中的作用和机制仍不清楚。本研究旨在探讨自噬是否能在LPS诱导的神经炎症中发挥神经保护作用。
用LPS、自噬抑制剂（3-甲基腺嘌呤，3-MA）或自噬激活剂（雷帕霉素）处理原代小胶质细胞和雄性C57BL/6 J小鼠。通过CCK-8检测、蛋白质免疫印迹分析、酶联免疫吸附测定、免疫组织化学和组织学染色等多种技术评估细胞活力、NF-κB通路激活、促炎细胞因子表达、M1极化、自噬标志物和神经元损伤。
LPS（1μg/mL）有效抑制细胞活力，刺激IκB-α和NF-κB的表达，同时抑制自噬蛋白表达。促炎细胞因子IL-1β和IL-6显著增加。与3-MA的作用相反，雷帕霉素处理抑制了LPS刺激后各组小胶质细胞向M1型的极化。细胞因子IL-1β、IL-6和CD86表达降低，Arg-1、IL-10和CD206表达增加证明了这一点。实验发现，侧脑室内注射LPS和3-MA的小鼠脑组织中IκB-α和NF-κB表达显著增加，促炎细胞因子水平升高，自噬水平降低，坏死神经元增加。小胶质细胞聚集增加，噬神经元作用增强。相反，注射雷帕霉素的小鼠神经元细胞自噬增强，促炎细胞因子表达和细胞凋亡减少，噬神经元作用降低。
增强自噬可通过抑制小胶质细胞M1极化和噬神经元作用有效减轻LPS诱导的神经炎症，从而保护神经元完整性。这些发现提示了在神经炎症性疾病中针对自噬的潜在治疗策略。
