BMSCs外泌体调控肾间质周细胞活化中蛋白翻译后核心岩藻糖基化的分子机制

Pericytes activation is the key event in the process of renal interstitial fibrosis. The overactivated multiple fibrotic signaling pathways including TGF-β and PDGF pathways, are the key base for the initiation and the mantainence of pericytes activation. Our previous creative studies have found that posttranslational core fucosylation regulated specifically by fucosyltransferase 8 (FUT8) was the common target for the abovementioned multiple fibrotic signaling pathways. In addition, BMSCs (bone marrow derived mesenchymal stem cells) or its exosome could inhibit core fucosylation and pericytes activation in renal interstitial fibrosis. But the underlying mechanism remained unclalified. Exosome may interact with target cells by surface-expressed ligands to deliver microRNA. To clarify the action mode of BMSCs, the spatial and temporal distribution patterns of BMSCs or exosome after injection will be traced by in vivo imaging two-photon, microscopy. MicroRNA expression microarray will be used to analyze the candidate microRNA regulating the expression of FUT8 in BMSCs exosome exposed to the microenvironment of pericytes activation. Multiple labelled quantitative proteomics followed by localization, clustering and protein-protein interaction analyses will be used to screen the candidate exosome surface-expressed ligand mediating the interaction with surface-expressed receptor in pericytes. These study will clarify the effect and the underlying mechanism of BMSCs derived-exosome on pericytes activation. We believe that our findings will provide a new theory evidence for BMSCs therapy on renal interstitial fibrosis and a basis for clinical transformation.

周细胞活化是肾间质纤维化进展关键事件。TGF-β、PDGF等多条“致纤维化信号通路”过度激活是周细胞活化发生和维系重要基础。我们前期创新性发现：①核心岩藻糖转移酶FUT8特异介导的蛋白质翻译后核心岩藻糖基化（CF）修饰是调控上述信号通路活性共同靶点；②骨髓间充质干细胞（BMSCs）外泌体可抑制CF修饰及周细胞活化，但机制不清。BMSCs外泌体可通过膜配体与靶细胞相互作用并传递microRNA。本项目采用活体成像、激光扫描共聚焦显微镜等研究静脉输注BMSCs及外泌体在体内分布时空特征，明确BMSCs作用方式；收集周细胞活化微环境下BMSCs外泌体，筛选调控FUT8表达的microRNA；采用多重标技术定量蛋白质组学，定位、聚类及蛋白间相互作用分析筛选与外泌体膜配体相结合的周细胞膜受体，以阐明BMSCs外泌体对周细胞活化的作用与机制，为干细胞外泌体治疗肾间质纤维化提供新理论依据及临床转化基础。

肾间质纤维化（RIF）是慢性肾脏病不断进展的共同病理表现与最后通路，目前尚无有效阻止手段。周细胞活化是RIF的主要病理特征。此外，成纤维细胞和巨噬细胞的活化也参与了RIF的进程。核心岩藻糖转移酶FUT8特异介导的蛋白质翻译后核心岩藻糖基化（CF）修饰是调控TGF-β、PDGF等多条“致纤维化信号通路”活性共同靶点，在周细胞激活和RIF中发挥关键作用。本项目研究发现间充质干细胞(BMSCs)来源的外泌体趋向于受损的肾脏中，并通过传递microRNA (miR)-34c-5p以调控CF进而抑制多种致纤维化细胞的活化和RIF。揭示了CD81-EGFR配体-受体复合物帮助外泌体miR-34c-5p进入周细胞、成纤维细胞和巨噬细胞的新机制。此外，在对不同纤维化疾病（糖尿病肾病、腹膜纤维化）模型的研究中发现并阐明了抑制CF修饰可以抑制纤维化进展的现象及作用机制。综上，本项目发现并阐明了BMSCs外泌体对周细胞等多种致纤维化细胞活化的作用与新机制，为干细胞外泌体治疗肾间质纤维化提供新理论依据及临床转化基础。发表 SCI 文章4篇，影响因子大于8的2篇。代表论文发表在Molecular therapy、 Kidney International等杂志上，最高影响因子11.454分。获得专利3项。国际肾脏病年会壁报3篇，国内肾脏病年会特邀报告5次。