血管壁微环境中内皮细胞分泌的外泌体调控尿毒症动脉中膜钙化的机制研究

Arterial medial calcification is a positive regulation process resembling bone formation in arterial wall, and the osteoblastic transdifferentiation of vsascular smooth muscle cells (VSMCs) is the cytologic mechanism of arterial medial calcification. Previous study only focus on the transdifferentiation of VSMCs, however, endothelial cell and VSMCs constitute the microenvirment of arterial wall, and there is little information about the endothelial cell regulting the osteoblastic transdifferentiation of VSMCs. Our previous studies demonstrate exosome free uremia serum could stimulate the secretion of exosome enrichment with miR-27b in endothelial cell. The exosome could be uptaken by the VSMCs, resulting in accelerating osteoblastic transdifferentiation of VSMCs. Our present study investigate the molecular mechanism involved in enrichment miR-27b exosome regulting osteoblastic transdifferentiation of VSMCs after these exosome uptaken by VSMCs. Using arterial medical calcification mice model and clinical arterial medial calcification sample, the relationship between miR-27b and arterial medial calcification will be investigated. Using Endothelial cell-specific miR-27b knockout mice, the effect of endothelia cell original miR-27b on arterial medial calcification will be analysised. The project devote to reveal the new mechanism of arterial calcification based on the arterial wall microenvirment. The project will find a new target for treatment of arterial medial calcification.

动脉中膜钙化是血管壁发生的一种类似骨形成的主动调节过程，血管平滑肌细胞（VSMCs）向成骨样细胞转分化是其细胞学基础。既往研究仅关注VSMCs的转分化，而内皮细胞和VSMCs构成血管壁微环境，内皮细胞调控VSMCs的转分化研究较少。我们前期研究发现尿毒症血清可促进内皮细胞分泌富含miR-27b的外泌体，该外泌体被VSMCs摄取后，促进VSMCs向成骨样细胞分化。本项目探讨尿毒症血清干预内皮细胞来源富含miR-27b的外泌体被VSMCs摄取后，调控VSMCs向成骨样细胞分化的分子机制。通过在动脉中膜钙化动物模型及临床标本中证实miR-27b与动脉中膜钙化的关系，并采用内皮细胞特异性敲除miR-27b小鼠，观察尿毒症加高磷饮食对动脉中膜钙化的影响。本项目从血管壁微环境出发，探讨内皮细胞调控VSMCs向成骨样细胞分化的分子机制，揭示动脉中膜钙化新的发病机制，为动脉中膜钙化防治提供新的作用靶点。

动脉中膜钙化是血管壁发生的一种类似骨形成的主动调控过程，导致血管弹性下降，高血流灌注器官灌注减少，严重危害患者健康。动脉钙化常见于慢性肾功能不全、糖尿病及衰老患者。本项目在前期研究的基础上，发现尿毒症血清或高磷干预内皮细胞分泌的外泌体，可被血管壁平滑肌细胞（VSMCs）摄取，并促进VSMCs向成骨样细胞分化。GW4869阻断内皮细胞外泌体分泌，可抑制内皮细胞和VSMCs共培养时导致的VSMCs钙化。高磷处理的内皮细胞分泌富集miR-670-3p的外泌体，该外泌体被VSMCs摄取后，miR-670-3p作用于靶基因IGF-1从而发挥促进VSMCs钙化的作用。并且内皮细胞分泌的外泌体在体内可被VSMCs所摄取，体内阻断内皮细胞分泌外泌体可缓解动脉钙化发生发展，miR-670-3p内皮细胞特异性敲入(miR-670-3pEC-KI)和敲除(miR-670-3pEC-KO)小鼠可分别促进或抑制动脉钙化的发生发展。终末期肾病患者血浆外泌体miR-670-3p与血清IGF-1水平负相关，与冠状动脉钙化评分负相关。本项目在原有研究的基础上，揭示动脉钙化新的发病机制，为动脉钙化防治提供新的作用靶点和理论依据。.在此项目的资助下，我们还发表了与动脉钙化相关的SCI论文22篇，培养博士2名，硕士2名，出版专著一本。