骨形态发生蛋白7修饰的骨髓间充质干细胞对糖尿病肾病纤维化的修复及相关机制

Diabetic kidney disease (DKD) is a serious complication of diabetes. At its core, DKD is a metabolic disorder which can also manifest itself in terms of local inflammation in the kidneys, and such inflammation can then drive the classical markers of fibrosis and structural remodeling. Therefore, resolution of immune-mediated inflammation is critical towards achieving a cure for DKD. Studies have shown that bone marrow mesenchymal stem cells and bone morphogenetic protein 7 (BMP7) can regulate inflammation. So, whether bone marrow mesenchymal stem cells can effectively combine the lentiviral vector of BMP7 overexpressing improved kidney fibrosis and significantly enhance the therapeutic effect of DKD. It is worth further study. The current study aims: (1) to detect the inflammation through immune response regulated by BMP7 modified mesenchymal stem cells in macrophage cultured in angiotensin II induced system in vitro; (2) to apply BMP7 modified mesenchymal stem cells regulation of the inflammatory response induced by macrophage in DKD rats. This study will clarify the regulatory mechanism of BMP7 modified bone marrow mesenchymal stem cells in inflammation and in the control of DKD progress, which would provide a theoretical basis for clinical treatment.

糖尿病肾病（DKD）是糖尿病严重的并发症。核心机制即代谢紊乱引起肾脏局部炎症以及炎症驱动的纤维化和结构的重塑。因此，针对免疫介导的炎症是治疗DKD的关键。有研究显示，骨髓间充质干细胞和骨形态发生蛋白7(BMP7)均可调控炎症，那么骨髓间充质干细胞和BMP7过表达慢病毒载体的联合应用是否更有效改善DKD肾脏纤维化并显著提高疗效，值得进一步研究。本课题拟：(1)利用体外血管紧张素II诱导的巨噬细胞培养体系，检测BMP7修饰的骨髓间充质干细胞通过免疫反应参与调控的炎性反应；(2)应用BMP7修饰的骨髓间充质干细胞调控DKD大鼠巨噬细胞诱发的炎性反应。本研究可望明确BMP7修饰的骨髓间充质干细胞参与调控DKD炎症的机制，为临床治疗提供理论依据。

糖尿病肾病（DKD）是糖尿病严重的并发症。核心机制即代谢紊乱引起肾脏局部炎症以及炎症驱动的纤维化和结构的重塑。因此，针对免疫介导的炎症是治疗DKD的关键。有研究显示，间充质干细胞和骨形态发生蛋白7（BMP7）均可调控炎症。本研究观察了骨髓间充质干细胞和BMP7过表达慢病毒载体的联合应用对于DKD肾脏炎症反应和纤维化的改善作用。首先，通过观察脐带间充质干细胞（UMSCs）的移植对局灶节段性硬化症(GSGS)小鼠炎症反应的作用，发现UMSCs通过调节促炎症因子TNF-α、促纤维因子TGF-β1及抗纤维化因子BMP-7的表达，从而抑制肾组织免疫炎症反应和细胞外基质（FN）沉积；以及UMSCs通过调节血循环中L-TH、棕榈油酸、3'-唾液乳糖的水平，从而改善FSGS小鼠肾组织氧化应激、抑制肾组织免疫炎症反应。其次，通过构建BMP7慢病毒过表达载体（pCDH-BMP7）并转染骨髓间充质干细胞（BMSCs），对DKD大鼠移植转染了pCDH-BMP7的BMSCs，通过western blot、免疫组化和ELISA等方法分析BMSCs结合pCDH-BMP7对DKD大鼠肾脏炎症反应的作用，结果显示，BMSCs结合pCDH-BMP7比单独pCDH-BMP7更有效的改善DKD大鼠的肾功能，且通过过表达BMP7基因调控肾脏炎症反应MAPK/NF-kB通路和纤维化TGF-β1/SMAD2/3信号途径，进而改善DKD病变进程。此外，通过构建BMP7过表达载体（pCDNA-BMP7），转染AngII诱导的巨噬细胞培养体系，确定了BMP7对于抑制巨噬细胞极化诱发的炎症反应的重要性，BMP7基因过表达诱导M1型向M2型极化，同时减弱M1型的炎症反应和氧化应激反应，且BMP7基因通过调控miR-23b-3p/NF-kB通路介导巨噬细胞炎症反应。综合上述结果，本研究为探讨间充质干细胞和BMP7基因治疗的基础研究奠定了坚实的工作基础，同时为临床慢性肾炎治疗而开展间充质干细胞作为载基因治疗有效工具的研究提供了启示性的理论依据。