NLRP3负调控MFG-E8致小胶质细胞胞葬障碍加剧心肺复苏后脑损伤的机制研究

小胶质细胞通过胞葬吞噬凋亡细胞并依此启动抗炎通路以维持内稳态。心肺复苏后凋亡神经元急剧增多，若胞葬不能相应增强，则凋亡神经元可大量积聚、继发坏死并释放促炎介质加剧脑损伤。然而，心肺复苏后小胶质细胞胞葬的变化规律及具体调控机制尚不明确。我们前期发现，心肺复苏后早期凋亡神经元清除受限；桥接胞葬的MFG-E8在心肺复苏后24h表达才轻微升高，而强促炎信号NLRP3则在6h已激活，且抑制NLRP3可上调MFG-E8及抗炎分子的表达。由此我们推测：心肺复苏后超早期NLRP3通路激活，抑制MFG-E8致小胶质细胞胞葬受阻，因而无法及时清除凋亡神经元及启动抗炎通路，最终使脑损伤加剧。本项目拟基于前期工作，在体内外模型上阐明MFG-E8介导的小胶质细胞胞葬在心肺复苏后的变化规律及其对脑损伤的影响，明确NLRP3对MFG-E8的调控作用，探讨胞葬激活抗炎通路的分子机制，为靶向调控胞葬防治脑损伤提供科学依据。

Microglia phagocytose apoptotic cells through efferocytosis and thereby initiate an anti-inflammatory pathway to maintain homeostasis. After cardiac arrest and cardiopulmonary resuscitation (CA/CPR), the number of apoptotic neurons increases sharply. If the efferocytosis could not be enhanced correspondingly, the apoptotic neurons could accumulate in large quantities, develop secondary necrosis and release pro-inflammatory mediators to aggravate the brain injury. However, the dynamic changes of microglial efferocytosis after CA/CPR and the specific regulatory mechanism are still unclear. We previously found that the clearance of apoptotic neurons was limited in the early stage after CA/CPR. The expression of MFG-E8, which opsonizes efferocytosis was only slightly increased 24h after CA/CPR, while the strong pro-inflammatory signal NLRP3 was activated at 6h, and inhibition of NLRP3 could up-regulate the expression of MFG-E8 and anti-inflammatory cytokines. Thus, we hypothesize that the activation of NLRP3 pathway at the ultra-early stage after CA/CPR impedes the microglial efferocytosis due to the inhibition of MFG-E8, which prevents the timely clearance of apoptotic neurons and the initiation of anti-inflammatory pathways, and finally aggravates the brain injury. Based on the previous work, this project aims to elucidate the change rules of MFG-E8-mediated microglial efferocytosis after CA/CPR and its effect on brain injury both in vivo and in vitro, clarify the regulatory role of NLRP3 on MFG-E8, and explore the molecular mechanism of efferocytosis activating anti-inflammatory pathways, so as to provide scientific basis for targeted regulation of efferocytosis in the prevention and treatment of brain injury.