VitminD/VDR调控染色质空间构象抗乙肝纤维化及其黄芪总黄酮干预的分子机制研究

乙肝纤维化是慢性肝病的重要病理过程，纤维化伴随多种细胞活化和极化的重编程，染色质空间构象变化是细胞重编程的重要环节。课题组前期发现：黄芪总黄酮能激活和增强VDR与VDRE的结合和转录调控；VDR激活抑制肝星状细胞活化和巨噬细胞促炎极化的重编程并调控基因表达；激活星状和巨噬细胞中的VDR，其结合的VDRE数显著增加，启动子区和非启动区VDRE的结合数和位置发生改变，暗示核内染色质构象改变。而VitaminD/VDR的这种调节染色质空间构象抗乙肝纤维化的分子机制尚不清楚。本项目将通过维生素D缺乏的乙肝纤维化小鼠和原代细胞(肝星状细胞和巨噬细胞)体内外模型的黄芪总黄酮干预，利用高通量染色质构象捕获技术(Hi-C)和传统分子细胞生物学等技术，揭示VitaminD/VDR在抗乙肝纤维化过程中调控星状和巨噬细胞重编程的作用机制，论证黄芪抗乙肝纤维化新的作用靶点，为中药黄芪抗纤维化治疗提供新的研究基础。

HBV-associated fibrosis is an important pathological process of chronic liver disease. Liver fibrosis is associated with reprogramming of multiple cellular activation and polarization. Chromatin spatial conformation change plays an important role in regulating cellular reprogramming. We found that the Total Astragalus Flavone (TAF) could activate and enhance the regulatory of Vitamin D/VDR and binding of VDR and VDRE. The activation of VDR inhibited the activation of hepatic stellate cells, macrophages proinflammatory polarization and expression of genes. The numbers of VDRE by activation of VDR in hepatic stellate cells and macrophages were increased significantly. The binding sites and numbers of VDRE in promoter regions and no promoter regions were changed after activation of VDR. It suggested chromatin conformation was changed. However, the molecular mechanism of chromatin conformation against HBV-associated fibrosis by Vitamin D/VDR is unclear. Vitamin D deficiency of HBV-associated fibrosis in mice and primary cells (hepatic stellate cells and macrophages) models by TAF treatment in vivo and in vitro were analyzed by high-throughput chromatin conformation capture technology (Hi-C) and traditional techniques such as molecular and cellular biology to reveal vitamin D/VDR in the regulation of gene expression in the process of HBV-associated fibrosis and stellate and the mechanism of action of macrophage reprogramming. The research will demonstrate the new target of astragalus against liver fibrosis and provide a new research basis for the treatment of astragalus against HBV-associated fibrosis.