脂肪细胞α7 nAChR调控肥胖时促酰化蛋白炎症效应的分子机制

Endogenous mechanism about obeisty-associated chronic inflammation and specific anti-proinflammatory drug development are the most pressing problem for medical researchers. α7 nicotinic acetylcholine receptor (α7 nAChR)-mediated cholinergic anti-inflammatory pathway brings a distinct breakthrough for inflammation intervention.The disruption of this cholinergic anti-inflammatory pathway might contribute to the continous inflammatory state related to pathogenesis of obesity. α7 nAChR-targeted therapeutic approaches has been a new hot point in alleviating inflammation and metabolic complications in obesity. In previous studies, we initially confirm that activated α7 nAChR on adipocytes could suppress the expression of some pro-inflammatory cytokines. However,its mechanism remain unclear. Acylation stimulating protein (ASP) is an adipokine which could induce early inflammation state in adipose tissue.Taken pro-inflammatory action triggered by ASP as footfold, the current study is designed to investigate in vivo and in vitro whether functional α7 nAChR on adipocytes could suppress ASP-induced inflammation, meanwhile, to evaluate the precise signaling mechanism. The involved methods will include laser scanning confocal microscope combined with immunohistochemical doublelabeling, realtime quantitative PCR, western blot,CBA and SAT,etc.Targeting this rapidly expanding area of anti-inflammatory pathway may provide novel therapeutic benefits in prevention and treatment of obesity-associated diseases

阐明肥胖时慢性炎症的发生机制以及寻找相关特异性抗炎药物是医学界亟待攻克的重大课题。α7 nAChR介导的胆碱能抗炎通路是近年来发现的内源性防御体系，其活性下调促进了肥胖时炎症反应的持续状态。α7 nAChR激动剂的研发已成为肥胖相关疾病靶向治疗的热点。申请人前期研究初步确立了3T3-L1脂肪细胞α7 nAChR活化对部分炎症因子表达的抑制效应,但对其机制了解甚少。目前认为新型脂肪因子促酰化蛋白（ASP）能够诱发脂肪组织的早期炎症状态。本研究以ASP的炎性效应为立足点，拟采用激光共聚焦显微镜荧光多重标记、实时定量PCR、免疫印迹、流式液相多重蛋白定量及悬液芯片等技术，从体内、体外两个层面探讨α7 nAChR功能状态对ASP炎症效应的影响及具体信号机制，为研发防治肥胖相关疾病的抗炎药物奠定新的理论基础与实践基础。

慢性炎症反应为脂代谢异常相关疾病的一个重要特征，我们的实验结果显示：（1）在脂肪细胞中，α7nAChR活化抑制ASP干预下趋化因子MCP-1和KC表达；其具体涉及的分子信号机制包括抑制ASP诱导的NFκB p65亚单位核转位、p65及p50亚单位与细胞核内DNA的结合力、IκBα的降解；STAT3转录后修饰和 p38磷酸化等环节。（2）在脂肪细胞与巨噬细胞体外共培养体系中，α7nAChR活化通过抑制巨噬细胞的炎症反应改善共培养状态下脂肪细胞的ASP敏感性。（3） 在肥胖鼠中，胆碱能系统活化降低高脂喂养肥胖鼠体重、血甘油三酯和ASP的水平，改善ASP敏感性。促进C5L2在脂肪、肝脏和肾脏组织的表达，但抑制其在肌肉组织的表达。本研究深入探讨了α7nAChR在缓解肥胖状态下ASP诱发的慢性炎症及ASP抵抗状态中的作用及具体信号分子机制,为脂代谢异常相关疾病的防治提供新视野。