Temporal balance between Notch and Wnt signaling during fracture healing

 描述（由申请人提供）：干细胞生物学领域正在以令人难以置信的速度发展，新技术定期出现，允许对成体干细胞生物学和组织再生的机制进行更深入的研究。Wnt信号和Notch信号被认为是调控成体干细胞增殖和分化的两条重要途径。过去的研究集中在Wnt信号的作用 在骨再生过程中，特别是其作为干细胞活化剂和促成骨生长因子的作用。然而，Notch信号传导途径没有受到太多关注，尽管在胚胎发育和成体组织再生（即肌肉）中有很好的证据表明Notch信号传导途径在祖细胞增殖中起核心作用。在本提案中，我们将重点关注Notch和Wnt信号通路，特别是这两条通路如何协调早期干细胞增殖和分化。(1)我们将首先表征损伤部位内骨祖细胞的Notch和Wnt反应性，并绘制这两种途径成员的空间和时间表达谱。(2)然后，我们将在早期增殖阶段抑制Notch信号传导，这将鉴定Notch信号传导调节增殖并潜在地影响随后分化的程度。(3)最后，我们将在体内独立激活Notch和Wnt信号通路，以确定这两条通路在成体骨干细胞活化过程中的潜在协同活性。虽然已经付出了很多努力来确定单一生长激素对骨再生的影响，但我们的研究旨在描述两个众所周知的途径之间精心策划的相互作用。这一提议可能会暴露出潜在的治疗靶点，这可能会导致未来仿生治疗算法的发展，其目标是增强人体自身的再生能力。我的职业目标是作为一名骨科临床科学家进行临床相关的基础研究。这个职业发展计划和研究提案将使我能够集中精力获得成为一名成功的临床科学家所需的技能。除了我的咨询委员会的五名成员之外，我的两名非常有成就的主要导师将保证我逐渐成长为骨生物学领域的有竞争力的研究人员。这种预期的学术增长，以及获得的新技能，将使我处于竞争独立R01资金的首要位置。

 DESCRIPTION (provided by applicant): The field of stem cell biology is advancing at an incredible speed, with new techniques emerging on a regular basis allowing for deeper investigations into the mechanisms underlying adult stem cell biology and tissue regeneration. Wnt signaling and Notch signaling have been identified as two key pathways that regulate adult stem cell proliferation and differentiation. Past research has focused on the role of Wnt signaling during bone regeneration, in particular on its role as a stem cell activator and pro-osteogenic growth factor. The Notch signaling pathway, however, has not received much attention, even though there is good evidence in embryonic development and adult tissue regeneration (i.e. muscle) that the Notch signaling pathway plays a central role in progenitor cell proliferation. In this proposal, we will focus on the Notch and Wnt signaling pathway, in particular how the two pathways orchestrate early stem cell proliferation and differentiation. (1) We will first characterize the Notch and Wnt responsiveness of osteoprogenitor cells within the injury site and map the spatial and temporal expression profile of members of both pathways. (2) We will then inhibit Notch signaling during the early proliferative phase, which will identify the degree t which Notch signaling regulates proliferation and potentially influences subsequent differentiation. (3) In the last aim, we will independently activate Notch and Wnt signaling in viv to define the potential coordinate activity between the two pathways during adult bone stem cells activation. While much effort has been exerted into identifying the effect of a singular growth hormone on bone regeneration, our research seeks to characterize a well-orchestrated interplay between two well-known pathways. This proposal may expose potential therapeutic targets, which may result in the future development of biomimetic treatment algorithms with the goal of enhancing the body's own regenerative capacity. My career goal is to conduct clinically relevant basic research as an orthopaedic clinician scientist. This career development plan and research proposal will allow me to focus my efforts on acquiring the desired skills that are necessary to become a successful clinician scientist. Receiving mentorship from my two highly accomplished primary mentors in addition to the five members of my advisory committee will guarantee my gradual growth into a competitive researcher in the field of bone biology. This expected academic growth in addition to the acquired new skills sets will place me in a prime position to compete for independent R01 funding.