SRF调控lincRNA-p21通过miR-1184-COL1A1通路促进腹膜纤维化

Previous work revealed that serum response factor (SRF) was involved in the phenotypic transition and fibrosis of the peritoneal membrane during treatment with peritoneal dialysis (PD). RNA-CHiP and lncRNA array analysis showed that, LincRNA-P21, which has a CArG element in the promoter, was found to be regulated by SRF by, but its role in peritoneal fibrosis remained unclear. Here, we found that, lincRNA-P21, which was found to be highly expressed in HG-induced HPMCs, was directly regulated by active SRF after HG stimulation in human peritoneal mesothelial cells (HPMCs) and that it contributed to peritoneal fibrosis. The silencing of lincRNA-P21 could inhibit HG-induced damage and alleviate fibrosis in PD rats in vivo, and caused cells migrated, and adhere closely in vitro. Mechanistically, lincRNA-P21 could inhibit the expression of miRNA-1184, which was characterized to target the COL1A1 messenger RNAs, and finally contribute to the adhesion of cellsin HG induced HPMCs. Overall, this study reveals a novel SRF-lincRNA-P21-miR-1184-COL1A1 axis that mediates damage and fibrosis in PD.

腹膜纤维化导致的超滤衰竭是腹膜透析失败的原因之一，而高糖导致的人腹膜间皮细胞（HPMC）损伤是纤维化的起始阶段，可逆转纤维化过程。实验组前期证实血清反应因子（SRF）是促进高糖诱导的HPMC损伤的重要分子，但其具体调控机制不清楚。LncRNA芯片筛选及预测发现，lincRNA-p21在高糖损伤的HPMC中显著增加，可能被SRF直接调控，CLIP-seq、miRNA芯片筛选及靶分子预测结果提示：lincRNA-p21可能通过海绵效应抑制miRNA-1184，进而上调靶分子胶原蛋白Ⅰ（COL1A1），最终导致胶原纤维过度沉积及腹膜纤维化。本研究在前期基础上，在体内外水平进一步探讨高糖损伤的HPMC中SRF调控的lincRNA-p21促纤维化机制以及其下游可能的miR-1184-COL1A1分子调控通路，进而从转录因子-lncRNA-microRNA-基因的调节水平探讨腹膜纤维化的分子机制。

本课题组长期以来致力于腹膜纤维化的相关机制研究，前期在JASN等杂志发表腹膜纤维化相关分子通路。同时，在前期工作基础上进一步发现，一些长链非编码RNA(lncRNA)可能受转录因子SRF的调控，而除了lincRNA-p21外，一些其他的lncRNA分子的高表达也会与腹膜纤维化的发生正相关，其机制可能通过抑制下游靶miRNA-1184，最终作用于COL1A1靶基因，促进胶原蛋白的沉积造成的。阐明SRF调控的LincRNA -miRNA-COL1A1分子通路，有助于揭示腹膜纤维化的相关机制，为逆转纤维化进程提供实验基础。. 本课题拟在前期对腹膜纤维化相关机制的研究基础上，在长链非编码RNA水平上，继续探讨lncRNA在高糖损伤导致的HPMC表型转换以及纤维化中的作用以及下游可能调控的分子通路。通过进一步的体内、外干预实验，以期探明在腹膜纤维化损伤早期，是否存在转录因子SRF在转录水平调控长链非编码RNA分子lncRNA以及下游可能调控的miRNA以及其可能的靶分子胶原蛋白的一个亚基COL1A1，最终导致胶原蛋白collagen（collagenⅠ）蛋白沉积过多这条分子通路，为寻找逆转细胞表型转换的治疗靶点奠定试验基础。经过筛选后，我们发现一个新的lncRNA RPL29P2，该分子可受SRF的调控，而lncRNA RPL29P2的高表达与腹膜纤维化的发生正相关，其机制可能通过抑制下游靶miRNA-1184，最终作用于COL1A1靶基因，促进胶原蛋白的沉积造成的。阐明SRF调控的LncRNA RPL29P2-miRNA-1184-COL1A1分子通路，为寻找逆转纤维化进程的分子靶点提供实验基础。并在此基金基础上，进行拓展实验，进一步发现H19的促腹膜纤维化作用及PD1/PDL1通过在腹膜纤维化中的作用机制及参与的相关免疫细胞及免疫分子。