缺氧诱导的骨髓间充质干细胞旁分泌在心肌重构中的作用及其机制的研究

项目名称： 缺氧诱导的骨髓间充质干细胞旁分泌在心肌重构中的作用及其机制的研究

项目编号： No.30871024

项目类型： 面上项目

立项/批准年度： 2009

项目学科： 轻工业、手工业

项目作者： 陈曦

作者单位： 中国医学科学院

项目金额： 32万元

中文摘要： 干细胞旁分泌改善缺血心肌心功能的观点已被广泛认可，但其机制尚不清楚。本项目研究证明，缺氧/缺血清可诱导骨髓间充质干细胞（MSCs）旁分泌抗炎因子IL-10，抑制心脏成纤维细胞增殖以及胶原表达，说明MSCs在缺血心肌中可通过旁分泌IL-10发挥抗心肌纤维化作用。我们以往工作表明，MSCs经溶血磷脂酸（LPA）处理后，再移植入缺血心肌，可显著增加毛细血管密度，且自身存活率提高。本研究证明，LPA可促进MSCs 分泌VEGF，但不影响其基因的表达；该作用与mitoKATP通道和蛋白质转运相关的ORP150有关。这说明LPA通过调节MSC旁分泌VEGF促进缺血心肌毛细血管新生，其机制与促进VEGF向胞外转运有关。此外，缺氧/缺血清诱导的MSC凋亡除涉及线粒体通路外，内质网应激也参与其中，LPA通过抑制p38活性阻止上述两凋亡通路，提高MSCs在缺血微环境中的存活率。以上研究从胶原代谢、血管新生和干细胞存活等多个侧面阐述了干细胞旁分泌以及内源性磷脂类活性小分子LPA在细胞移植、心脏重构调节中的积极作用，为MSCs移植缺血心肌参与心脏逆重构、改善心功能的旁分泌机制提供了新的科学依据。

中文关键词： 骨髓间充质干细胞；细胞移植；旁分泌；溶血磷脂酸；心脏重构

英文摘要： It is widely recognized that stem cell transplantation improve cardiac function by its paracrine response, but its mechanism is unclear. The present studies have shown that both the conditioned medium from hypoxia?SD-stimulated mesenchymal stem cells (MSC-CM) and IL-10 efficiently inhibited cardiac fibroblast proliferation and collagen expression in vitro. And hypoxia?SD promoted mesenchymal cells secriting IL-10. It suggests that mesenchymal cell-secreted IL-10 prevents cardiac fibrosis in a paracrine manner under ischaemic conditions. Our previous work shows that, MSCs treated by lysophosphatidic acid (LPA) significantly increased capillary density and kept higher graft survival cells in ischemic myocardium. This study demonstrated that LPA promoted VEGF release from MSCs, but failed to increase VEGF mRNA and protein levels. mitoKATP channel and transport-related protein ORP150 involved LPA-induced VEGF secretion, indicating that by regulating MSC paracrine VEGF, LPA promote angiogenesis in ischemic myocardium and the underlying mechanism is related the promotion of VEGF to the extracellular transportation. In addition, hypoxia / serum-induced apoptosis of MSCs, besides involving mitochondrial pathway, the pathway of endoplasmic reticulum stress was also involved. LPA improved MSC survival in the ischemic microenvironmen by inhibiting p38 activity to prevent the above apoptosis pathways. Taken together, paracrine response of MSCs and endogenous phospholipids molecules-LPA play the positive roles for MSCs transplantation in improving heart function and reversing remodeling of ischemic myocardium by regulation of collagen metabolism, angiogenesis and stem cell survival. This study provides new scientific evidence for paracrine mechanism of MCs transplantation.

英文关键词： mesenchymal stem cells; cell transplantation; paracrine; lysophosphatidic acid; heart remodeling