健脾补肾、清肠化湿介导SDF-1/CXCR4促进MSCs归巢调控miR-21治疗溃疡性结肠炎机制研究

Abstract：Increased expression of miR-21 due to the decrease of MSCs migration and differentiation is the significant mechanism for the immune disorders and hardly repair of intestinal barrier of UC.Regulating IL-6/STA3/miR-21 by MSCs though SDF-1 /CXCR4 axis is a new method for the treatment of UC. Although previous studies have shown that JianPiBuShen,QingChangHuaShi decoction (sheng huang qi,chao bai zhu,bu gu zhi,yi zhi ren,huang qin,huang lian,di yu,mu xiang,zhi gan cao) could promote MSCs migration and differentiation,reduce the inflammatory reaction, and repair intestinal barrier, the specific mechanism is still unknown. This research aims at exploring the specific mechanism of JianPiBuShen，QingChangHuaShi decoction for up-regulating SDF-1/CXCR4 axis to promote MSCs homing, and then regulating miR-21 though IL-6/STA3,repairing intestinal barrier by vivo and vitro experiments, so as to provide scientific basis for the clinic.

间充质干细胞（MSCs）归巢减少导致miR-21水平升高是溃疡性结肠炎（UC）免疫紊乱、肠黏膜损伤难以修复的重要原因。介导SDF-1/CXCR4促进MSCs归巢，通过IL-6/STA3下调miR-21已成为UC治疗的重要靶标。前期研究表明健脾补肾,清肠化湿方（生黄芪、炒白术、补骨脂、益智仁、黄芩、黄连、地榆、木香、炙甘草）能够促进MSCs归巢，减轻UC炎症反应，修复肠黏膜，但是否介导SDF-1 /CXCR4促进MSCs归巢，进而调控IL-6/STA3/miR-21的具体机制有待进一步阐明。本课题拟在此基础上，通过体外和体内实验，探索健脾补肾、清肠化湿复方及其拆方介导SDF-1 /CXCR4促进MSCs归巢，调控IL-6/STA3减少miR-21表达，进而调控免疫、修复肠黏膜屏障的作用机制，为临床用药提供依据。

溃疡性结肠炎(UC)是重要的结肠癌前病变，研究表明间充质干细胞（MSCs0）可以通过再生被破坏的组织或者对免疫系统进行调节，修复受损黏膜起到治疗作用。课题组前期研究发现健脾补肾、清肠化湿方具有促进MSCs增殖迁移、向受损肠道归巢。本研究进一步阐释健脾补肾、清肠化湿方促进MSCs组织归巢的相关信号通路，以及通过MSCs调控miR-21表达进而调节免疫、维护肠屏障治疗溃疡性结肠炎的机制，并通过复方、拆方和成分研究，解析健脾补肾、清肠化湿的优效配伍。研究结果表明：健脾补肾、清肠化湿可以通过上调SDF-1 /CXCR4信号轴，增加ERK蛋白表达，促进MSCs以及LPS预处理的MSCs的迁移趋化能力，增加模型大鼠肠干细胞标记物LGR5、ephrin-B3、Msi-1表达，拆方研究配伍健脾组效果更佳；体内外实验结果表明健脾补肾、清肠化湿可以抑制miR-21、pri-miR-21以及pre-miR-21的表达，其机制可能与IL-6/STA3/通路有关，能够下调IL-6和JAK2/STAT3水平，进而影响下游靶基因NF-κB、PDCD4、JAG1的表达，减轻炎症反应；主要活性成分没食子酸能够体外缓解MSCs的细胞周期阻滞，减少凋亡，增强其迁移侵袭能力，降低miR-21、STAT3的表达量。本研究以MSCs为枢纽，证实了健脾补肾、清肠化湿方降低炎症反应、黏膜修复的作用机制，通过拆方研究解析健脾补肾、清肠化湿药物配伍作用，为进一步开发治疗UC的中药新药打下了科学基础。