基于光敏超分子水凝胶对干细胞微环境的光调控及干细胞响应机制研究

Modulation of stem cell differentiation represents one of the most important topics in the interdisciplinary research between chemistry and biomedical studies. Stem cells are able to respond to various changes in their microenvironment. We propose to develop new modulation methods of stem cell microenvironment by photo-modulation of the 3D matrix formed by the self-assembling of photo-responsive short peptides, which will allow us to further explore the intracellular mechanism responsible for the regulation of stm cell differentiation upon stimulation by microenvironmen change. Based on our previous work on the construction of photo-responsive short peptide self-assembling systems, we propose to use short peptides modified with tetrazole moieties as the hydrogelators to form highly biocompatible supramolecular hydrogels that allow 3D encapsulation of long-term culture of various stem cells. Then the intramolecular or intermolecular photo-click reaction will be applied to disturb the microenvironment of stem cells either by change of physical properties or chemical components around the stem cells encapsulated in the supramolecular hydrogel medium. The temporal and spatial resoluted photo-modulation of cellular microenvironment of stem cells will allow us to explore unknown mechanisms realted to the regulation of stem cell differentiation upon stimulation by microenvironment change. The change of intracellular regulators such as microRNAs in stem cells will be elucidated and possible microRNA involved regulatory pathway in the regulation of different stem cell differentiation will be explored.

干细胞的可控分化是当前化学与生物医学交叉的研究领域一大重要的研究方向，本项目拟探索通过光对干细胞三维生长微环境的调控进而对干细胞的分化等行为进行有效干预的方法，并基于此研究干细胞在对微环境中刺激因素发生响应时细胞内相应的调控机制。项目拟在已有的前期研究基础上，通过能发生分子内或分子间的光点击反应的光敏短肽分子的自组装形成的超分子水凝胶作为干细胞三维培养的新型光响应型基质材料，通过光诱导下的快速光反应对自组装体系的扰动，实现对于干细胞培养的三维微环境的时空分辨性调控，进而研究不同干细胞对其生长微环境的物理或化学性质变化产生响应的规律，并结合干细胞内相关调控因子如微小核糖核酸等在响应前后的变化情况发现与干细胞分化调控相关的新的分子机制。项目基于申请人课题组在光敏超分子水凝胶和细胞内微小核糖核酸调控等方面已有的研究基础提出，因此项目特色鲜明且具有较强的创新性和可行性。

在本项目执行过程中，我们对原申请研究内容进行了拓展和延伸，通过发展新型光诱导生物正交反应以及结合现有光催化生物正交反应构建了几种不同类型的光敏超分子水凝胶以及分子探针，并借助它们开展了一系列化学生物学研究，具体包括：（一）构建了可对光以及酶双重响应的超分子水凝胶，实现了细胞表面纤维自组装的调控；（二）基于光敏性超分子水凝胶实现了细胞外微小核糖核酸向细胞内的运输；（三）基于光点击化学反应建立了分子探针构建的简便新方法；（四）基于光点击化学反应建立了细胞内微小核糖核酸靶基因鉴定的新方法；（五）结合光诱导的生物正交反应构建功能短肽实现了微小核糖核酸的靶向运输、治疗及功能成像；（六）发展了可见光诱导光点击化学反应；（七）基于光点击化学反应构建可对紫外光和可见光双重响应的光敏超分子水凝胶，实现了干细胞分化的调控。这些研究成果为细胞微环境调控的化学生物学研究提供了新的工具或方法，也为相关生物医学研究提供新的工具或理论基础。基于这些研究成果，本项目总计发表SCI论文十一篇，申请发明专利一项。