SDF-1/CXCR4生物轴介导Exendin-4调控棕色脂肪来源心脏干细胞心梗后归巢的作用研究

Stem cells’ homing recruitment is the key element of stem cells’ transplantation for treatment of myocardial infarction. Our previous study had found that cardiac stem cells’ amplification in rats’ brown adipose tissue could be stimulated by specific situation. Exedin-4, a long-lasting analogue of glucagon-like peptide-1 as one of endogenous active substances, can exert pleiotropic biological effects including regulating metabolic stimulation. The present study aims to establish a stable and efficient BADCSCs’ culture system in vitro at first. Then, the change of Exendin-4 regulatory BADCSCs cell migration and homing were observed, with expression pattern related to the molecular mechanism of SDF-1/CXCR4 signaling pathway mediated by downstream molecule Rac GTPase. Furthermore, BADCSCs from Fluc+ transgenic mice were intravenously injected after myocardial infarction. BADCSCs homing, as well as tissue and functional improvement were determined. Through this study, we aim to eventually put forward new direction for developing adult stem cells application, and further provide theoretical basis and experimental support to optimize the stem cells technologies on treating myocardial infarction.

干细胞归巢是制约干细胞移植治疗心肌梗死疗效的关键瓶颈。棕色脂肪组织内存在一类具有自发心肌分化功能的心脏干细胞。我们的前期研究发现，棕色脂肪来源心脏干细胞（BADCSCs）可在寒冷刺激下实现体内扩增。Exendin-4是胰高血糖素样肽-1的长效类似物，可通过调节代谢刺激影响细胞生物学性能。本项目拟先通过细胞分离和流式分选技术，建立稳定、高效的BADCSCs体系；随后体外观察Exendin-4调控BADCSCs细胞迁移的变化现象，重点阐明SDF-1/CXCR4信号通路介导上述变化的分子机制以及下游效应分子开关Rac GTP酶的表达规律；最后利用转基因小鼠分离标记Fluc+的BADCSCs经尾静脉移植治疗心肌梗死，通过活体成像技术评价exendin-4对BADCSCs归巢的影响，并测定组织功能改善情况。为进一步拓展成体干细胞运用领域提出新的方向，为优化干细胞治疗心肌梗死提供理论基础和实验支持。

目的与意义：干细胞归巢是制约干细胞移植治疗心肌梗死疗效的关键瓶颈。Exendin-4是胰高血糖素样肽-1的长效类似物，可通过调节代谢刺激影响细胞生物学性能。本项目先通过细胞分离和流式分选技术，建立了稳定、高效的BADCSCs体系；随后体外观察Exendin-4调控BADSCs细胞迁移的变化现象，重点阐明了SDF-1/CXCR4信号通路介导上述变化的分子机制以及下游效应分子开关Rac GTP酶的表达规律；最后利用标记后的干细胞移植治疗心肌梗死，通过活体成像技术评价了exendin-4对干细胞移植疗效的影响，并测定组织功能改善情况。本研究进一步拓展了成体干细胞运用领域的新方向，为优化干细胞治疗心肌梗死提供理论基础和实验支持。.结果：1. 分析培养的BADSCs表面抗原为CD29+, CD34-, CD45-, CD90+和CD133+。2. Exendin-4能够以剂量依赖方式提高体外培养BADSCs的数目。3. 随着Exendin-4浓度的提高，细胞迁徙能力增强。4. 验证了Exendin-4对干细胞体外迁移的影响，阐明了Exendin-4对干细胞趋化体系SDF-1/CXCR-4信号通路的调节作用。5. 揭示了Exendin-4对干细胞迁移归巢的作用通过关键蛋白Rho GTP酶来实现。6. 成功建立干细胞在体示踪平台，利用活体成像技术证实褪黑素纳米微粒可提高干细胞的心梗区域定植率。7. Exendin-4能够增强干细胞的迁移能力，褪黑素纳米微粒能协助干细胞更有效的对抗氧化应激损伤，提高移植后存活能力。8. 发表3篇SCI文章（最高影响因子5.6）；2篇Medline文章；1篇核心期刊文章。