新型AMPK激动剂IMM-H007促进高密度脂蛋白胆固醇逆转运功能机制研究

机体胆固醇逆转运(RCT)功能是高密度脂蛋白胆固醇抗动粥最重要的内源性保护机制。腺苷三磷酸结合盒转运体(ABCA1)是RCT起始阶段限速蛋白，也是国际新药研发领域的热点药靶。我国自主研发的新型AMPK激动剂IMM-H007增强多种动物体内RCT功能。其在既不抑制胆固醇酯转移关键分子CEPT，也不影响核转录因子LXR的情况下，如何抑制ABCA1降解而发挥增强RCT功能，是本研究拟解决的科学问题。本项目拟采用流式细胞术、激光共聚焦、高分辨质谱、全细胞膜片钳和同位素标记等技术，阐明以下假说：IMM-H007可能通过抑制钙蛋白酶活性及其与ABCA1的PEST序列结合或抑制泛素蛋白酶与ABCA1结合，增强细胞膜表面ABCA1稳定性，从而促进胆固醇逆转运。本研究打破了目前胆固醇逆转运药物研发集中在以胆固醇酯转移蛋白CEPT和转录因子LXR为靶标的困境，为胆固醇逆转运药物的研发提供新靶点和新思路。

The function of reverse cholesterol transport (RCT) is the most important endogenous protective mechanism of HDL against atherosclerosis. Adenosine triphosphate binding cassette transporter (ABCA1) is considered to be a rate-limiting protein in the initial stage of RCT, and a popular drug target in the field of international new drug development. IMM-H007, a domestically researched and developed AMPK agonist, can enhance the RCT function in various animals. It is the scientific problem to resolve that how to suppress ABCA1 degradation and enhance RCT function without inhibiting a key molecule in cholesterol ester transfer CEPT and a nuclear transcription factor LXR exerted by the presence of IMM-H007. By using flow cytometry, laser confocal, high-resolution mass spectrometry, whole-cell patch-clamp, and isotope labeling, this investigation intends to clarify the hypothesis that IMM-H007 may inhibit the degradation of ABCA1 protein by inhibiting the activity of calpain and its binding to ABCA1 PEST sequence or inhibiting the binding of ubiquitin protease to ABCA1, thus enhancing the stability of ABCA1 on the cell membrane surface and promoting cholesterol reversal. These findings not only break the bottleneck of the current research and development of cholesterol reverse transport drugs focusing on the cholesterol ester transfer protein CEPT or the transcription factor LXR, but also provide new targets and strategy for the development of cholesterol reverse transport novel drugs.