Regenerating Blood Vessels Using iPS Cells

描述（由申请人提供）：诱导多能干细胞（iPS）具有修复患病或创伤血管的巨大潜力。事实上，我们首先使用全反式维甲酸（atRA）成功地诱导iPS细胞分化为平滑肌细胞（SMC）。我们的长期目标是使用患者来源的iPS细胞再生功能性人类血管。使用iPS细胞进行功能性血管再生的关键是 分化和维持血管SMC的收缩表型。总体假设是，关键信号分子与由先进支架限定的仿生微环境的协调是实现iPS衍生的血管SMC的收缩表型和功能性血管再生所需的。 最近发现Hippo-YAP信号通路在维持iPS细胞多能性中起关键作用。初步的数据支持，我们假设Yap 1是一个关键的分子，抑制iPS细胞分化为血管平滑肌细胞和抑制血管平滑肌细胞的收缩表型。我们开发了3D多孔和纳米纤维（NF）支架，并发现NF结构增强了iPS细胞向血管SMC的分化和对照支架的收缩表型。在本项目中，我们将首先在二维培养系统中确定雅普在调控iPS细胞向血管SMC分化和血管SMC表型转换中的作用。然后，我们将开发最佳的NF支架，以确定Yap 1在三维培养系统中调控iPS细胞向血管SMC分化的作用。我们还将在支架内开发控释系统，以最大限度地利用atRA沿着Yap 1调节，增强血管SMC分化及其成熟收缩表型的维持。在这些机械理解和先进技术的基础上，我们将设计血管，并使用生物反应器和大鼠植入模型对其进行评估。 通过实现这些具体目标，我们将提高对iPS细胞分化为血管SMC的机制理解，并开发关键技术，以推进基于患者的iPS细胞用于人类血管再生的治疗效用。

DESCRIPTION (provided by applicant): Induced pluripotent stem (iPS) cells have enormous potential for the repair of diseased or traumatized blood vessels. Indeed, we, among the first, have successfully induced iPS cell differentiation to smooth muscle cells (SMC) using all-trans retinoid acid (atRA). Our long-term goal is to regenerate functional human blood vessels using patient-derived iPS cells. The key to a functional blood vessel regeneration using iPS cells is the differentiation and maintenance of the contractile phenotype of the vascular SMC. The overall hypothesis is that the coordination of the key signaling molecules with the biomimetic microenvironment defined by an advanced scaffold is required for achieving the contractile phenotype of iPS-derived vascular SMC and functional blood vessel regeneration. The Hippo-YAP signaling pathway has recently been found to play a critical role in maintaining iPS cell pluoripotency. Supported by preliminary data, we hypothesize that Yap1 is a critical molecule inhibiting the differentiation of iPS cells to vascular SMC and suppressing the contractile phenotype of vascular SMC. We developed 3D porous and nanofibrous (NF) scaffolds and found that the NF architecture enhanced iPS cell differentiation to vascular SMC and the contractile phenotype over control scaffolds. In this project, we will first define the role of Yap in regulating iPS cell differentiation to vascular SMC and vascular SMC phenotypic switch in a 2D culture system. We will then develop optimal NF scaffolds to define the role of Yap1 in regulating iPS cell differentiation to vascular SMC in 3D culture system. We will also develop controlled release system inside the scaffolds to maximize the utility of atRA along with Yap1 modulation in enhancing the vascular SMC differentiation and their mature contractile phenotype maintenance. Built on these mechanistic understandings and advanced technologies, we will engineer blood vessels and evaluate them using bioreactors and a rat implantation model. By accomplishing these specific aims, we will improve mechanistic understandings of iPS cell differentiation to vascular SMC and develop key technologies to advance the therapeutic utility of patient based iPS cells for human vascular regeneration.