NLRC5与DNA甲基化修饰调控枯否细胞NF-κB对肝纤维化的影响

The Inflammatory factors secreted by KC is tumor-initiating link that cause liver damage and fibrosis.Inhibition of NF-κB can significantly slow down liver fibrosis.In KC, the activation of NF-kappa B is the key factor of inflammatory factors secreted by KC. NLRC5 (NOD protein family) can inhibit the activation of NF-kappa B and limit the release of inflammatory factors, but the roles in the different organizations are controversial. Our study found that the expression of NLRC5 is lower in the formation of liver fibrosis. With the reversal of liver fibrosis gradually increased, the application of 5-azadC can regulate the expression of NLRC5. Our initial study has confirmed that DNA methylation in epigenetic modification can regulate the formation of liver fibrosis, even though the exact mechanism is not clear. It has not been reported that whether the activation of KC is regulated by DNA methylation, or whether the inhibition of NLRC5 can promote the expression of NF- kappa B, thus promote the secretion of inflammatory cytokine .How to change NLRC5 in the activation of KC and whether increased expression of NLRC5 can inhibit the process of the liver fibrosis also has not been reported in the literature. This topic launchs research around the mechanism of NLRC5 that can regulate the inflammatory factor secreted by KC, in order to clear the effect of NLRC5 on NF- kappa B and the secretion of inflammatory factors in KC, as well as exploring the interaction relationship of DNA methylation and NLRC5.It is benificial for understanding the mechanism of liver fibrosis and looking for new drug targets the provide new ideas.

激活肝脏的KC分泌大量炎症因子是引起肝脏损伤和纤维化的始动环节。抑制NF-κB表达可明显减缓肝纤维化。NF-κB在KC炎症因子分泌中占重要位置，而NLRC5(NOD蛋白家族)可阻止NF-κB活化，抑制炎症因子释放。前期研究发现肝纤维化形成过程中NLRC5呈低表达，随着肝纤维化逆转逐渐升高；采用5-azadC可调控NLRC5的表达。晚近发现DAN甲基化表观遗传修饰可调控肝纤维化的形成，具体机制尚未明确。KC活化是否受DNA甲基化的调控，是否调控NLRC5影响NF-κB，从而影响肝纤维化形成发展的进程，还未见文献报道。本课题拟围绕NLRC5调控Kupffer分泌炎症因子的机制展开研究，明确Kupffer细胞NLRC5对NF-κB、分泌炎症因子的影响，及对HSC增值凋亡的作用；探讨DNA甲基化表观修饰与NLRC5的相互作用关系。为理解肝纤维化发病机制及寻找新的药物靶点提供新的思路。

抑制NF-κB表达可明显减缓肝脏炎症与肝纤维化等病变,NF-κB在星状细胞增殖活化与巨噬细胞炎症因子分泌中占重要位置，有研究报道NLRC5(NOD蛋白家族)可阻止NF-κB活化，抑制炎症因子释放。本项目重点观察了NLRC5在肝脏疾病中的作用及其可能的作用机制。.项目研究NLRC5对炎症因子影响，发现沉默NLRC5明显抑制p-IκBα的表达，抑制炎症因子的表达，研究还发现，NLRC5在调控NF-κB信号通路的同时，其自身表达也受NF-κB通路控制。鉴于巨噬细胞在肝脏疾病发生发展中的重要作用，项目研究了急性肝损伤中NLRC5的变化及对巨噬细胞炎症因子分泌的影响，发现NLRC5亦可通过调控JAK2/STAT3信号通路调控炎症因子的分泌。进一步探讨NLRC5表达变化的调控机制发现，甲基转移酶(DNMT1)对NLRC5的蛋白表达具有调控作用。.项目以肝纤维化患者肝脏为研究对象，发现NLRC5表达增加，荧光染色发现NLRC5与肝星状细胞标志物α-SMA共定位现象，提示NLRC5可表达与肝星状细胞。以人肝星状细胞LX-2为研究对象，发现沉默NLRC5可抑制LX-2活化，过表达NLRC5则促进LX-2活化。沉默NLRC5可促进核内P65蛋白表达，提示NLRC5可能是通过调控NF-κB信号通路促进LX-2活化增殖。肝纤维化自发逆转为肝纤维化的防治提供了新的方向，鉴于NLRC5在肝纤维化发生发展中的重要作用，项目探讨了NLRC5对HSC活化增殖与逆转的影响。发现活化的LX-2细胞中NLRC5表达增高，逆转期则明显降低；沉默NLRC5可促进活化的HSC发生逆转。.上述研究提示，NLRC5作为调控肝脏疾病的重要蛋白，深入研究其功能，明确其蛋白晶体结构，开展小分子化合物设计，可能为肝脏等炎症免疫性疾病的防治提供新的靶点。