基质硬度（Stiffness）调控血管内皮祖细胞分化及在组织工程血管化中的应用

Angiogenesis is a key process required for regenerative medicine and complete organ engineering. The establishment of functional vascularization with appropriate arterial-venous differentiation remains a major challenge for the widespread translation of tissue engineering applications into medical practice. Recent studies have revealed that stem cell lineage commitment was sensitive to the biophysical status of the microenvironment. For example, the inherent stiffness of the extracellular matrix has a profound impact on cell morphology, proliferation, and cell fate decision. Therefore, in this study, we attempt to develop a two-dimensional polydimethylsiloxane(PDMS)-based substrate and a three-dimensional polyethyleneglycol(PEG) hydrogel, respectively. These two biomaterials are both capable of simulating the physiologically relevant matrix stiffness of both venous and arterial tissue. The bone marrow derived endothelial progenitor cells(EPCs) will be cultured on substrates of different stiffness. And the variations of expressions of arterial and venous specific markers in EPCs will be evaluated. Furthermore, the PEG hydrogel model will be used in nude mice for the blood vessel formation assay. The expressions of arterial and venous specific markers of new vessels in hydrogels of different stiffness will be measured. The effect of different degrees of substrate stiffness on the arterial-venous differentiation of EPCs and new vessels will be revealed and the underlying mechanism will be explored as well. This work may represent a potential method for regulating arterial-venous differentiation for the fulfilment of diverse functions of the vasculature.

血管化是组织工程中的难点，构建功能性动静脉血管系统是组织工程在实际应用中的攻坚课题。本课题组最新研究发现，细胞外基质硬度（Stiffness）对血管内皮祖细胞向动脉-静脉内皮方向分化等生物学行为有重要调控作用。本研究拟合成Stiffness可精确调控的二维PDMS材料和三维PEG水凝胶，模拟体内动脉、静脉内皮细胞基质的硬度微环境，深入研究Stiffness-Ras/RhoA- Notch-EphB4/EphrinB2-VEGF信号通路对内皮祖细胞定向分化的调控机制。在此基础上制备梯度硬度的三维PEG水凝胶开展体内研究，期望形成方向可控的功能动静脉血管网络。本研究可为精确调控内皮祖细胞分化和动-静脉功能血管网络形成提供研究基础，为组织工程血管化研究提供新的思路和研究模型。

本课题围绕组织工程血管化硬度仿生材料构建、内皮祖细胞分化的关键问题，阐明硬度Stiffness对内皮祖细胞分化方向的调控机制，建立通过硬度Stiffness的调节实现对内皮祖细胞分化调控的诱导体系，探索血管生成的最佳硬度仿生材料和最适条件。通过本项目的研究，成功构建血管化硬度仿生材料，搭建内皮祖细胞向动、静脉内皮细胞分化和组织工程血管化的研究平台。发表通讯/第一作者SCI论文42篇，累积影响因子370。其中影响因子＞6的论著30篇，影响因子＞10的论著5篇，主编英文专著1部。在读博士研究生8名，硕士研究生9名，毕业硕士研究生9名。作为第二完成人获得教育部自然科学奖二等奖、中华医学会科技二等奖、华夏医学科技二等奖。在承担课题期间，课题负责人新获得国家自然科学基金2项（82171006，81970986），四川省青年科技创新团队1项。担任Journal of Biomedical Nanotechnology（SCI）副主编，Nanoscience and Nanotechnology Letters（SCI） 副主编，Cell Proliferation，Chinese Chemical Letters, Frontiers in Bioengineering and Biotechnology和Frontier in Materials（SCI）编委。担任International College of Dentistry Fellow，中国医学装备协会组织再生分会常委，中华口腔医学会口腔种植专委会委员，四川省口腔医学会牙槽外科分会副主任委员。