Mechanisms of dental pulp stem cell differentiation into functional endothelium

描述(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。我们最近证明了人类牙髓干细胞在体内分化为血管内皮细胞，血管内皮细胞自我组织成功能血管。这一令人兴奋的观察表明，牙髓干细胞除了分化为生成新组织的实际细胞(例如成牙本质细胞、成骨细胞)外，还可以产生支持“组织形成”的高代谢需求的血管。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)增强了牙髓干细胞的血管生成能力。然而，血管内皮生长因子诱导牙髓干细胞分化为内皮细胞所需的信号转导事件尚不清楚。众所周知，无翼(Wnt)信号通路在决定细胞发育过程中的命运中起着关键作用。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Wnt信号在引导牙髓干细胞走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生成和骨形成之间密切相关。然而，干细胞介导的血管生成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一个实验模型，以评估调节干细胞对血管生成表型的承诺的机制，并确定干细胞来源的血管在矿化组织形成中的作用。这一建议的机制假设是：“血管内皮生长因子和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，我们提出了以下特定目标：-特定目标1：研究血管内皮生长因子诱导牙髓干细胞分化为内皮细胞的机制。-特定目的#2：评估Wnt信号在决定牙髓干细胞命运中的作用。-特定目标#3：了解牙髓干细胞血管分化与牙本质形成之间的功能关系。意义：干细胞疗法的临床翻译需要了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为新组织和器官的生成提供所需的血管。我们的最终目标是更深入地了解牙源性间充质干细胞的生物学，以造福于需要组织再生的患者。

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.