分阶段调控诱导多能干细胞分化在肌腱损伤治疗的应用和机理研究

Tendon injuries occur frequently during sports and other rigorous physical activities. Due to their limited vascularity, innervation and cellular content, natural healing of tendon tissue is extremely inefficient. Human-induced pluripotent stem cells (hiPSCs) are a highly promising cell source for regenerative medicine. However, the application study of hiPSCs in tendon repair and regeneration is rare. Our team previous demonstrated physical property of substrates such as stiffness and topography has been reported to induce tendon stem cells differentiation into tenocyte. Here we are planning to develop a stepwise strategy to induce hiPSCs differentiate into teno-lineage by both physical and chemical approaches. Firstly hiPSCs will be differentiated into MSCs on smooth plastic surface through an EMT (Epithelial-Mesenchymal Transition) process. Subsequently, the hiPSC derived MSCs were induced by TGF beta to Scx positive tendon stem/progenitor cells, followed by seeded onto well-aligned nanoscale fibers to differentiate into tenocyte-like cells. The in situ tendon repair study further conducted to confirm tenogenic induce hiPSC had significant effect on improving the structural and mechanical properties of tendon injury repair. These findings develop the stepwise tenogenic strategy can be adopted to induce hiPSCs differentiation for tissue regeneration and provide significant insight to the underlying mechanism for tenogenesis.

诱导多能干细胞（iPS）具有与胚胎干细胞类似的分化潜能，却规避了伦理争议和干细胞移植医学上的免疫排斥问题，成为了再生医学研究领域的热点。而iPS在肌腱组织工程中实现应用面临的核心问题是缺少调控全能干细胞向肌腱系特异分化的高效方案。本课题组前期研究发现，细胞外基质的排列显著正向调控了多能干细胞的腱系分化（Biomaterials2010,2015）。本课题在此基础上拟结合干细胞生物学、材料工程学和组织工程学手段，提出生化物理手段相结合的策略分阶段实现诱导iPS向肌腱系的特异分化，并进一步通过体内异位和原位的肌腱修复再生实验，评估阶段诱导iPS向肌腱分化的可行性和功效性。在此基础上深入探索Tet1调控的细胞DNA甲基化水平参与物理特性诱导细胞分化的调控机制。预期本课题将通过分步诱导方案实现全能干细胞向多能干细胞的分化并进一步向肌腱系特异的诱导分化，也为iPS在肌腱组织工程的应用提供全新的思路。

肌腱病是最常见的运动损伤之一，然而其关键的发病机理尚不明确且临床缺乏长期有效的治疗方法。诱导多能干细胞（iPSC）具有与胚胎干细胞类似的分化潜能，是再生医学研究领域的热点。而iPSC在肌腱组织工程中实现应用面临的核心问题是缺少调控全能干细胞向肌腱系特异分化的高效方案。本课题结合干细胞生物学、材料工程学和组织工程学手段，提出生化物理手段相结合的策略分阶段实现诱导iPSC向肌腱系的特异分化，并进一步通过体内异位和原位的肌腱修复再生实验，评估阶段诱导iPSC向肌腱分化的可行性和功效性。在此基础上深入探索材料表面拓扑结构这一物理学信号转化为细胞核内的生物化学信号，为组织工程走向临床提供理论基础。.本研究发现：1，成功获取和鉴定了iPSC，并在平板上诱导其向iPSC-MSC分化。2，构建了有序和无序的支架，发现有序支架更能诱导iPSC-MSC向肌腱细胞分化。3，在跟腱损伤动物模型中，有序支架组取得了更好的疗效。.本研究建立了iPSC向肌腱细胞分步诱导的方案，为iPSC在肌腱组织工程的应用提供全新的思路。