COTL1在非酒精性脂肪性肝病发生发展中作用的研究

At present, prevalence of nonalcoholic fatty liver disease (NAFLD) raises dramatically, especially the adolescent. NAFLD has become the second largest liver disease following chronic hepatitis in China. Although the relative importance of insulin resistance, oxidative stress, mitochondrial injury, adipocytokines and low-grade chronic inflammation has been elucidated, the mechanism of NAFLD remains to be indistinct. Our work was based on previously identified differential expressed proteins from high fat diet (HFD) and methionine choline deficiency diet (MCD) animal models in our lab. Coactosin-like protein (COTL1) was associated with lipid metabolism and inflammation, and it up-regulated invariably in all NAFLD stages. 42 cases of human liver biopsy tissue related analysis showed COTL1 was significantly positively related to inflammatory activity and lipopexia of NAFLD. Knockdown of aberrant COLT1 could relieve hepatic steatosis and liver injury. These results suggest that COTL1 may play an important role in NAFLD development and progression especial in NASH stage. We also found COTL1 mainly localized in Kuffer cells(KC) and liver sinusoidal endothelial cells(LSEC) in the normal liver. In this study, we specificity knockout COTL1 from KCs and LSECs to find its influence on macrophage polarization balance, LSEC differentiation status, fat accumulation and inflammatory related pathways. We try to discover the molecular mechanism of COTL1 promote the occurrence and development of NAFLD.

当前非酒精性脂肪性肝病发病率不断增高且渐趋低龄化，在我国很可能发展成为仅次于慢性病毒性肝炎的第二大肝病。目前，NAFLD发病机制尚不明确，缺乏有效的预防和治疗措施。前期，我们基于NAFLD小鼠模型中，筛选到与脂肪代谢和炎症相关的分子COTL1蛋白；42例人肝穿活检组织相关分析结果亦显示COTL1与NAFLD的炎症活动度和脂变率呈显著正相关；敲低异常上调的COTL1能够减少肝脏脂质异常蓄积并减轻肝损伤。以上结果提示，COTL1在NAFLD的发生发展过程中，特别是NASH阶段发挥重要作用。细胞分布实验，发现该分子主要定位在肝脏枯否细胞和肝窦内皮细胞。本课题，我们希望在前期工作的基础上，采用细胞特异性敲除COTL1小鼠模型，从细胞间协作角度探索COTL1对巨噬细胞极化平衡、肝窦内皮细胞分化状态及对肝实质细胞脂肪堆积、炎性相关通路的影响，探讨COTL1促进NAFLD 发生发展的分子机制。

当前非酒精性脂肪性肝病（NAFLD）发病率不断增高且渐趋低龄化，在我国很可能发展成为仅次于慢性病毒性肝炎的第二大肝病。NAFLD包括肝脏组织中一系列组织学异常，从单纯脂肪变性到脂肪性肝炎，进而可能发展为肝纤维化和肝硬化，这可能导致肝癌的发生。目前，NAFLD发病机制尚不明确，缺乏有效的预防和治疗措施。. 前期阶段，基于蛋氨酸胆碱缺乏（MCD）饮食诱导的NAFLD模型的小鼠肝脏差异蛋白质组分析，筛选到COTL1参与NAFLD发生发展的进程相关。COTL1分子是一种F-actin结合蛋白的高度同源蛋白质，目前国内外对 COTL1的分子功能研究尚浅，值得注意的是，未见COTL1与NAFLD发生发展相关的研究报道。. 本课题我们分别用MCD饮食和高脂饮食（HFD）诱导成功建立了NAFLD小鼠模型，证实COTL1在MCD和HFD饮食诱导的NAFLD模型小鼠肝脏中的表达量均是上调的。42例人肝穿活检组织相关分析结果亦显示COTL1与NAFLD的炎症活动度和脂变率呈显著正相关。利用腺相关病毒载体特异性敲低肝脏COTL1的表达能够改善肝脏脂肪变性，证实COTL1具有促进NAFLD发生发展的作用。细胞分布实验，我们发现该分子主要定位在肝脏枯否细胞（KCs）和肝窦内皮细胞（LSECs）。在本课题的研究中，我们重点构建了肝脏KCs特异性和LSECs特异性COTL1敲除的工具鼠，在此基础上，HFD饮食分别诱导肝脏KCs特异性和LSECs特异性COTL1敲除的NAFLD小鼠模型，发现肝脏KCs特异性和LSECs特异性敲除COTL1都能够减轻肝脏脂肪变性，减缓肝脏单纯性脂肪变向脂肪性肝炎发展转变的进程。研究进一步证明COTL1发挥作用的机制与ALOX5有关，且COTL1对NAFLD的促进作用是由肝脏实质细胞与非实质细胞协同调控完成。COTL1作为NAFLD发生发展进程中一个可能的分子靶标，为NAFLD的防治开辟新的治疗靶点和策略。.