Mechanisms of dental pulp stem cell differentiation into functional endothelium

描述（由申请人提供）：问题：牙髓含有多能干细胞，在牙齿发育和组织再生中发挥关键作用。我们最近发现人牙髓干细胞分化为血管内皮细胞，这些细胞在体内组织成功能性血管。这一令人兴奋的观察结果表明，牙髓干细胞可以产生血管，支持“组织制造”的高代谢需求，此外还可以分化为产生新组织的实际细胞（例如成牙本质细胞，成骨细胞）。然而，控制牙髓干细胞血管生成命运的机制尚不清楚。这些知识是最大限度地利用牙髓干细胞在临床应用中的分化潜力所必需的。假设：在初步研究中，我们证明了血管内皮生长因子（VEGF）增强牙髓干细胞的血管生成潜力。然而，VEGF诱导牙髓干细胞分化为内皮细胞所需的信号事件是未知的。无翅（Wingless，Wnt）信号通路在细胞发育过程中起着决定细胞命运的重要作用。值得注意的是，Wnt抑制牙髓干细胞向成牙本质细胞的分化。但是Wnt信号在引导牙髓干细胞向血管生成命运中的作用尚不清楚。有趣的是，在发育过程中观察到血管发生和骨形成之间的紧密相关性。然而，干细胞介导的血管发生对牙本质形成的影响尚不清楚。在这里，我们将使用牙齿作为实验模型，用于评估调节干细胞向血管生成表型的承诺的机制，并确定干细胞衍生的血管在矿化组织形成中的作用。该建议的机制假设是：“VEGF和Wnt信号调节牙髓干细胞的血管生成命运”。为了验证这一假设，我们提出了以下具体目标：-具体目标#1：研究VEGF诱导牙髓干细胞分化为内皮细胞的机制。 - 具体目标#2：评估Wnt信号传导对牙髓干细胞命运的确定的功能。 - 具体目标#3：了解牙髓干细胞的血管分化和牙本质形成之间的功能关系。重要性：基于干细胞疗法的临床转化需要理解控制这些细胞分化命运的机制。该项目旨在开发基于机制的方法，利用干细胞的血管生成潜力，提供生成新组织和器官所需的血管。我们的最终目标是利用对牙齿来源的间充质干细胞生物学的更深入理解，使需要组织再生的患者受益。

DESCRIPTION (provided by applicant): The Problem: The dental pulp contains pluripotent stem cells that play a critical role in tooth development and tissue regeneration. We have recently demonstrated that human dental pulp stem cels diferentiate into vascular endothelial cells that organize themselves into functional blood vessels in vivo. This exciting observation suggest that dental pulp stem cells can give rise to blood vessels that support the high metabolic demands of "tissue-making", in addition to differentiate into the actual cells that generate the new tissue (e.g. odontoblasts, osteoblasts). However, the mechanisms that control the vasculogenic fate of dental pulp stem cells are not understood. Such knowledge is required to maximize the use of the diferentiation potential of dental pulp stem cells in clinical applications. Hypothesis: In preliminary studies, we demonstrated that vascular endothelial growth factor (VEGF) enhances the vasculogenic potential of dental pulp stem cells. However, the signaling events required for VEGF-induced differentiation of dental pulp stem cells into endothelial cells are unknown. It is known that the Wingless (Wnt) signaling pathway plays a critical role in the determination of cell fate during development. Notably, Wnt inhibits the differentiation of dental pulp stem cells into odontoblasts. But the role of Wnt signaling in directing dental pulp stem cells towards a vasculogenic fate is not understood. Interestingly, a tight correlation between vasculogenesis and bone formation is observed during development. However, the impact of stem cel- mediated vasculogenesis on dentin formation is not known. Here, we will use the tooth as an experimental model for the evaluation of mechanisms that regulate the commitment of stem cells towards the vasculogenic phenotype and determine the role of stem cell-derived blood vessels in mineralized tissue formation. The mechanistic hypothesis of this proposal is: "VEGF and Wnt signaling regulate the vasculogenic fate of dental pulp stem cells". To test this hypothesis, we propose the following specific aims: -Specific Aim #1: To study mechanisms involved in VEGF-induced differentiation of dental pulp stem cells into endothelial cells. -Specific Aim #2: To evaluate the function of Wnt signaling on the determination of dental pulp stem cell fate. -Specific Aim #3: To understand the functional relation between vascular differentiation of dental pulp stem cells and dentinogenesis. Significance: The clinical translation of stem cell-based therapies requires the understanding of mechanisms that control the differentiation fate of these cels. This project aims at the development of mechanism-based approaches that exploit the vasculogenic potential of stem cells to provide the blood vessels required for the generation of new tissues and organs. Our ultimate goal is to employ a deeper understanding of the biology of mesenchymal stem cells of dental origin to benefit patients that require tissue regeneration.