Periostin在Nestin+心脏间充质干细胞调节巨噬细胞治疗心肌梗死的作用研究

In myocardial infarction (MI), local inflammatory response is an important pathogenesis of myocardial remodeling and heart failure. Cardiac stem cells are reported to play an important role in cardiac repair, and becomes an advanced and promising field in the medical research. However, specific stem cell type and mechanism of cardiac repair in MI remains unclear. Our previous study have found that Nestin+ cells from heart of Nestin-GFP transgenic mice were resident cardiac mesenchymal stem cells (CMSCs). When transplanted in the animal model of MI, these Nestin+ cells promote the repair of cardiac function, significantly reduce macrophage infiltration in the onset of the disease and increase M2 type of macrophage. Moreover, Peirostin, a macrophage regulatory factor, was highly expressed in these cells.Taken together, these results suggests that Nestin+ CMSCs are involved in the macrophage-mediated inflammatory response after MI. Here, we explore the direct mechanism in which Nestin+ CMSCs modulate the inflammatory response of macrophages by in vitro and in vivo models, gene sequencing, gene interference and periostin knockout mice model. This study is the first to demonstrate that the mechanism of Nestin+ CMSCs in cardiac repair by targeting Periostin-mediated M2 macrophages recruitment, and also further clarifies the type of cardiac stem cells suitable for transplantation and provides a novel and reliable theoretical basis for cell therapy in MI.

心肌梗死（MI）后局部炎症反应是心肌重塑和心力衰竭的重要发病机制。心脏干细胞研究提示其在心脏修复中发挥重要作用，成为医学前沿重点发展领域，然而对其干细胞类型以及作用机制尚不明确，亟待阐明。申请人利用Nestin-GFP转基因小鼠发现，Nestin+细胞为心脏间充质干细胞（CMSCs），移植于MI动物模型体内可以促进心功能修复，明显减少了疾病早期巨噬细胞的浸润及增加M2型巨噬细胞，且该细胞自身高表达巨噬细胞调节因子Periostin, 提示其可能参与MI后巨噬细胞炎症反应的调解。据此，本研究拟利用体内外模型、基因测序、基因干扰及Periostin基因敲除小鼠模型等方法，探讨Nestin+CMSCs的特性及调控巨噬细胞炎症反应的直接作用机制。通过上述研究，阐明Nestin+CMSCs在心肌修复中的作用机制，也为进一步明确适合移植的心脏干细胞类型，及进行MI细胞治疗提供新的思路和可靠的理论依据。

本研究利用巢蛋白Nestin做为间充质基质细胞（Mesenchymal Stromal Cells，MSCs）的筛选标记，分别从心脏和骨髓中分选得到Nestin+的细胞，并通过体外培养和基因测序分析比较，证实了心脏来源的Nestin+细胞具备MSCs的生物学特性。然而在，干细胞特性上，不同组织来源MSCs之间存在组织差异性。.本课题组首次证实心脏Nestin+cMSCs对急性心肌梗死（Acute myocardial infarction，AMI）的治疗效果明显优于骨髓Nestin+bmMSCs，表现为降低AMI小鼠梗死病灶炎症细胞的浸润，降低梗死面积及纤维化程度，改善心脏功能。该结果提示，组织特异性的MSCs在治疗其靶组织的损伤修复中较非特异性组织来源的MSCs发挥至关重要的角色，该现象的发现可提高MSCs对AMI的临床治疗效果的稳定性。进一步研究发现心脏Nestin+cMSCs的靶向迁移和促进抑炎的M2巨噬细胞转化能力均明显强于骨髓Nestin+bmMSCs；后续表达谱测序分析中筛选的P2ry1嘌呤受体和Periostin旁分泌蛋白分别是介导心脏Nestin+cMSCs靶向迁移和促进M2型巨噬细胞转化的关键分子；进而通过干扰Periostin和过表达P2ry1实验，证实了它们在心脏MSCs治疗AMI中的作用优势，并系统阐明了相关机制。该研究为提高MSCs治疗AMI的稳定性，推进MSCs的临床应用奠定了坚实的理论和实验基础，并提供新的治疗靶点。