CD169经DAP12抑制巨噬细胞M2极化并加重急性胰腺炎的机制研究

急性胰腺炎（AP）是内科常见急危重症，巨噬细胞极化在AP炎症风暴中起重要作用，但机制未明。申请人前期研究发现，AP小鼠模型胰腺组织CD169表达水平升高，敲除CD169减轻胰腺损伤；CD169负调控巨噬细胞M2极化及DAP12/Syk通路。结合前期结果及文献资料，申请人推测，CD169可能与DAP12结合并竞争抑制Syk磷酸化，通过负调控其下游PI3K/Akt/mTORC1和JNK/c-JUN信号通路，分别从转录水平和组蛋白乙酰化水平抑制巨噬细胞M2极化，促进炎症因子风暴并最终加重AP。本项目拟通过流式细胞分析、免疫荧光、免疫共沉淀、染色质共沉淀、siRNA等技术，结合CD169-白喉毒素受体小鼠、在体内和体外等不同水平揭示CD169经DAP12抑制巨噬细胞M2极化并加重急性胰腺炎损伤的机制研究。本项目预期结果将揭示CD169调控巨噬细胞功能在AP中的作用及机制，并为疾病治疗提供新依据。

Acute pancreatitis is one of the most common acute and severe gastrointestinal diseases. Macrophage is reported to be an important activator in the inflammation storm during AP. The mechanism of its pathogenesis remains unclear. Our previous studies found that the expression of CD169 was unregulated in AP mice model. Knocking out of CD169 alleviated the severity of pancreatitis, promoted M2 macrophage polarization and induced the activation of DAP12/Syk pathway. Based on preliminary study and literature research, our hypothesis was that CD169 negatively regulates M2 macrophage polarization in a DAP12 depedent manner through PI3K/Akt/mTORC1 and JNK/c-JUN pathways, which further promotes pro-inflammation response and aggravates pancreatic injury. In this research project, by using flow cytometry, immunofluorescence, co-immunoprecipitation and siRNA-dependent silence or knockout, as well as CD169-DTR mice, we aim to determine the influence of CD169 on M2 macrophage polarization and AP severity in vivo and in vitro as well as explore the specific mechanism of DAP12 dependent pathways. The results of this study will illuminate the influence of CD169 in AP and macrophage polarization and provide theoretical evidence of further clinical application.