巨噬细胞乙酰化修饰介导小檗碱抗炎效应和改善胰岛素抵抗的作用

Berberine (BBR) is a natural compound isolated from Chinese herbs, Coptis chinensis. One of the most important pharmacological properties of BBR is anti-inflammatory effect. BBR is used for the inflammatory diseases in TCM’s clinical practice, due to the action of heat clearing and detoxicating. Berberine also has been found to improve insulin resistance and the dysfunction of glucose and lipid metabolism and insulin resistance through inhibiting the expressions the proinflammatory factors and the activation of inflammatory signal pathway in macrophages and adipocytes. Current evidence shows that the inflammatory state and polarization of macrophages is control by histone acetylation which is catalyzed by histone deacetylase (HDACs). Our previous studies found that BBR inhibited the activity of ClassⅠ/ⅡHDACs and recovered the level of protein acetylation reduced by LPS. So, we hypothesize that histone acetylation in macrophages may links anti-inflammatory property of BBR with the improvement of insulin resistance..In this study, we will explore that the effect of BBR on the activity of HDACs and the changes of histone acetylation in HDAC over-expressed macrophages and HDAC transgenic mice, and the relationship of this effects to the improvement of insulin resistance. Furthermore, the specific site of lysine of histone deacetylation at proinflammatory factor genes will be detected in HDAC over-expressed macrophage cell line and macrophages isolated from macrophages-specific HDAC over-expressed mice treated with BBR. Finally, new histone acetylated targets induced by berberine in dependent of HDAC will be identified with SILAC-based HPLC-MS/MS technology of proteomics..The results of this study will be helpful to elucidate the epigenetics’ mechanism underlining BBR’ effects on inflammation and metabolic diseases in new viewpoint. It will provide a clue for research on diabetes in Chinese medicine and for potential mechanism of BBR’ s multiple pharmalogical actions.

抑制炎症反应是清热解毒中药黄连的有效成分小檗碱最重要的药理特性，也是小檗碱改善胰岛素抵抗和糖脂代谢紊乱的显著作用机制，而巨噬细胞的炎症反应受到组蛋白乙酰化的调控，前期研究发现小檗碱能抑制组蛋白去乙酰化酶（HDAC）活性和增强蛋白的乙酰化，表明巨噬细胞组蛋白乙酰化可能调控小檗碱的抗炎作用，并借此机制改善胰岛素抵抗。.本课题以巨噬细胞的组蛋白乙酰化为切入点，运用高表达HDAC巨噬细胞和HDAC转基因小鼠，借助细胞和分子生物学手段和技术，探明小檗碱抗炎和改善机体和组织胰岛素抵抗的作用与抑制HDAC导致组蛋白乙酰化的关系，借助ChiP-PCR技术明确小檗碱抗炎作用的巨噬细胞组蛋白乙酰化位点，运用蛋白质组学技术，探寻受小檗碱调节的新乙酰化分子靶点。.本研究从表观遗传修饰深入阐明小檗碱抗炎作用和治疗代谢性疾病的关系，对中医药抗糖尿病方药的研究思路做出探索，也为小檗多种药理效应的机制研究提供线索。

抑制炎症反应是清热解毒中药黄连的有效成分小檗碱最重要的药理特性，也是小檗碱改善胰岛素抵抗和糖脂代谢紊乱显著的作用机制，而巨噬细胞的炎症反应受到组蛋白乙酰化的调控。本研究首先通过定量蛋白质组学和定量乙酰化组学技术发现小檗碱改变脂多糖刺激的巨噬细胞内蛋白乙酰化水平，这些蛋白主要富集在炎症、代谢信号、信号转导等相关通路；同时发现小檗碱下调巨噬细胞内NF-κB的p65亚基上310位点的乙酰化水平，抑制了NF-κB的核转位和活性，并导致IL-1β、TNF-α和MCP-1等炎症因子转录和分泌的减少；进一步发现小檗碱是通过下调乙酰化酶p300的表达减少p65亚基上310位点的乙酰化修饰，发挥抗炎作用；在急性炎症小鼠中，小檗碱通过调节巨噬细胞p300/p65Lys310轴抑制机体炎症反应；在慢性炎症肥胖小鼠模型中验证了上述结果，并观察到胰岛素抵抗的显著改善。本研究探寻到小檗碱调节的巨噬细胞乙酰化新的分子靶点，从表观遗传修饰深入阐明小檗碱抗炎作用和治疗代谢性疾病的机制，也为小檗多种药理效应的机制研究提供新的线索。