Controlling endothelial fate and vascular assembly from pluripotent stem cells

 描述(由申请人提供)：创造功能性血管的能力是血管治疗和组织工程的关键一步。目前，我们对人诱导多能干细胞(HiPSCs)向血管内皮细胞(ECs)和周细胞的分化还没有完全的了解和控制。在胚胎发生过程中，血管生成形成原始神经丛，随后血管生成，内皮细胞萌发、延长、管腔形成并结合形成管。同时，这些新生的ECs管通过血管周围细胞的募集而稳定下来。传统上，在体外构建功能性微血管结构需要在三维支架材料中嵌入两个不同的细胞来源：内皮细胞和周细胞。我们实验室建立了一种新的贴壁培养系统，可以从HiPSCs中获得早期血管细胞(EVCs)的双细胞群体。这些血管内皮细胞由VEcad+和PDGFR？细胞组成，可分别成熟为内皮细胞和周细胞，并可在水凝胶支架中自组织形成三维多细胞血管网络。这种方法为研究HiPSCs血管分化过程中的命运决定提供了很好的机会。它还有助于构建临床应用的血管结构。我们的目标是：(1)建立一种无饲养层、贴壁的培养体系，以获得高比例的内皮细胞和周细胞；(2)分析内皮细胞和周细胞分化的时空动力学；以及(3)实时分析细胞的相互作用和功能 自组织的血管网络。为了实现我们的目标，提出的研究战略结合了干细胞和血管生物工程技术。这些目标的成功实现将对改进的血管疗法产生相当大的临床影响，并将拓宽我们对血管发育和修复的理解。

 DESCRIPTION (provided by applicant): The ability to create functional vasculatures is a crucial step towards vascular therapy and tissue engineering. Currently, we still do not have full control and understanding of vascular differentiation including endothelial cells (ECs) and pericytes, from human induced pluripotent stem cells (hiPSCs). During embryogenesis, vasculogenesis gives rise to the primitive plexus followed by angiogenesis where ECs sprout, elongate, lumenize and coalesce to form tubes. Concurrently, these nascent ECs tubes are stabilized via the recruitment of perivascular cells. Traditionally, engineering of functional microvasculature constructs in vitro involves embedding two distinct cell sources of ECs and pericytes within a three-dimensional (3D) scaffold material. Our lab has established a novel adherent culture system to derive a bi-cellular population of early vascular cells (EVCs) from hiPSCs. These EVCs are composed of VEcad+ and PDGFR¿¿ cells that can mature to ECs and pericytes respectively, and can self-organize to a 3D multicellular vascular network in a hydrogel scaffold. This approach provides great opportunities to study fate decisions during vascular differentiation of hiPSCs. It also contributes to the construction of vascular structures for clinical applications. Our aims are: (1) Establish a feeder free, adherent culture system to obtain high ratio of EC to pericyte from hiPSCs; (2) Dissect the spatial and temporal kinetics of EC and pericyte differentiation; and (3) Analyze real- time cellular interactions and functionality of self-organized vascular networks. To achieve our aims, the proposed research strategy combines techniques in stem cell and vascular biology engineering. Successful completion of these aims has considerable clinical impact with respect to improved vascular therapeutics and will broaden our understanding of vascular development and repair.