种子细胞MSC释放的CXCL8募集宿主细胞促进组织工程骨成骨作用机制的研究

项目名称： 种子细胞MSC释放的CXCL8募集宿主细胞促进组织工程骨成骨作用机制的研究

项目编号： No.81471802

项目类型： 面上项目

立项/批准年度： 2015

项目学科： 医药、卫生

项目作者： 许建中

作者单位： 中国人民解放军第三军医大学

项目金额： 70万元

中文摘要： 以间充质干细胞（MSC）为种子细胞构建的组织工程骨（TEB）是修复大节段骨 缺损最有希望的策略之一。种子细胞通过募集宿主MSC加速成骨修复，但机制不明，严重制约了 TEB 的进一步应用。我们前期发现，种子细胞可分泌大量CXCL8募集宿主MSC，此过程中CXCL8/CXCR1/2-Akt通路表达上调，MMPs等蛋白酶活性增强。结合国内外研究，提出种子细胞通过释放CXCL8激活CXCR1/2-Akt通路促进宿主MSC的募集和增殖分化的假说。为此，拟在体外初步观察此通路对宿主MSC 迁移、增殖和成骨分化的影响及作用比例；在体内通过应用CXCL8 条件基因敲除小鼠、CXCR1/2拮抗剂和Akt抑制剂，进一步验证和评价此通路对宿主MSC迁移、增殖和成骨分化的影响及可能作用机制。本研究将进一步阐明 TEB 的成骨机制，为提高 TEB 的成骨效能、开发组织工程新产品提供理论基础和新思路。

中文关键词： 骨组织工程；间充质干细胞；C-X-C；模体配体；8；Akt；信号通路；宿主细胞募集

英文摘要： Tissue-engineered bones (TEB) seeded with mesenchymal stem cells (MSC) are considered one of the most promising strategies in treating large bone defect. Previous studies have shown that seeded MSC accelerate bone repair via recruiting host MSC. However, the underlying mechanisms remain elusive, greatly constraining the further application of TEB. In our preliminary experiments, seeded donor MSC could secrete abundant CXCL8 to recruit host MSC. During this process, the expressions of major signal molecules in the CXCL8/CXCR1-Akt and CXCL8/CXCR2-Akt pathways were elevated, and the activity of certain proteases, such as MMPs, were enhanced. Based on the current literature, we here propose the hypothesis that by releasing CXCL8, seeded MSC activate the CXCL8/CXCR1-Akt and CXCL8/CXCR2-Akt pathways in host MSC, which account for the acceleration of recruitment, proliferation and osteogenic differentiation of host MSC. For verification, we will preliminarily observe the effects of these two pathways on the migration, proliferation and osteogenic differentiation of host MSC in vitro, as well as their functional ratios. With the utilization of CXCL8 conditional know-out mice, CXCR1/2 antagonists and Akt inhibitors, the effects of these two pathways on host MSC and the possible mechanisms will be evaluated and verified further. This study will clarify the osteogenic mechanism of TEB to a deep further, and provide theoretical foundation and novel insights to the promotion of osteogenic efficacy of TEB and the development of tissue-engineered products.

英文关键词： bone tissue engineering;mesenchymal stem cells;CXCL8;Akt signal pathway;host cell recruitment