CXCR4/CXCR7在SDF-1诱导平滑肌祖细胞参与哮喘气道重塑中的作用及信号转导机制研究

airway remodeling is an important pathological character of asthma, its pathogenesis is unclear. Smooth muscle progenitor cells (SPCs) possess themselves of character of mesenchymal stem cells and smooth muscle cells. Recent data suggest SPCs contributes to vascular remodeling, it is unclear whether SPCs play the same role in airway remodeling as in vascular remodeling. Stromal cell-derived factor-1（SDF-1）is an important α-chemokine that binds to its cognate receptor CXCR4 and CXCR7 and thus regulates mesenchymal stem cells migration, proliferation and homing, etc. But it is unclear whether SDF-1/CXCR4/CXCR7 axis regulates SPCs migration, proliferation and homing, and how about it's downstream signal pathway. In this study, we will isolate rat bone marrow mesenchymal stem cells and then differentiate them into SPCs. Chronic female rat asthmatic model will be established, SPCs which isolated from male rats are transplanted to female rat asthmatic model by intravenous injection, airway samples of asthmatic rat were examinated Sry (sex-determining region on the Y chromosome) positive cell count by hybridization in situ to evaluate SPCs niche and differentiation, at the same time , roles of SPCs contributes to airway remodeling of asthma through SDF-1/CXCR4/CXCR7 axis is investigated. In vitro, CXCR4 and/or CXCR7 inhibitor, phosphoinositide 3-kinase (PI3K) inhibitor Wortmannin are used to explore roles of CXCR4/CXCR7 in smooth muscle progenitor cells induced by SDF-1 migration, proliferation, apoptosis and signal pathway. We now sought to elucidate that SPCs migration, proliferation and apoptosis induced by SDF-1/CXCR4/CXCR7 axis contributes to airway remodeling of asthma through activated PI3K/NF-ΚB signal pathway, SPCs is a new therapeutic target in asthmatic airway remodeling.

气道重塑是哮喘重要病理特征，其发病机制未明。平滑肌祖细胞(SPCs) 具有干细胞及平滑肌细胞特征，参与多种血管重塑性疾病，SPCs是否也参与了哮喘气道重塑？SDF-1/CXCR4/CXCR7在祖细胞归巢中的作用及信号转导机制如何？目前未见报道。本课题将大鼠骨髓间充质干细胞诱导分化为SPCs，复制雌性慢性哮喘大鼠模型时移植雄性大鼠SPCs，原位杂交检测性别差异基因Sry阳性细胞在气道壁内定植和分化情况,并观察阻断SDF-1/CXCR4/CXCR7对哮喘大鼠气道重塑中SPCs作用的影响。利用CXCR4和/或CXCR7拮抗剂、PI3K抑制剂等体外考察CXCR7/CXCR4在SDF-1诱导的SPCs迁移、增殖、凋亡中的作用及其信号转导机制。力求阐明SDF-1/CXCR4/CXCR7通过激活PI3K/NF-ΚB信号通路诱导SPCs迁移、增殖、凋亡并在哮喘气道重塑中起重要作用，为哮喘治疗开拓新的领域。

气道平滑肌的增生、肥大以及分泌异常是哮喘气道重塑的主要病理过程。已有研究表明,气道平滑肌来源于平滑肌祖细胞(SPCs)，但SPCs 是否参与哮喘气道重塑以及SDF-1/CXCR4/CXCR7 信号轴在诱导平滑肌祖细胞参与哮喘气道重塑中的作用机制目前未见报道。本课题利用细胞培养、细胞迁移实验、流式细胞术、原位杂交、RT-PCR、MTT 等分子生物学技术，从动物、细胞、分子水平探讨SDF-1/CXCR4/CXCR信号轴在诱导平滑肌祖细胞迁移、增殖、凋亡参与哮喘气道重塑中的作用，首次证实平滑肌祖细胞(SPCs)可以迁移至气道壁并参与气道重塑过程。首次证实SDF-1 /CXCR4/CXCR7信号轴在诱导平滑肌祖细胞迁移至气道壁参与哮喘气道重塑中起重要作用。对哮喘气道重塑的发病机制进行了全新的诠释，可望给哮喘治疗开辟更加广阔的前景。