Regulation of Quiescence and Activation in Skin Stem Cells

描述（由申请人提供）：本提案的长期目标是了解如何适当调节干细胞的活性以维持体内平衡和组织完整性。毛囊是皮肤重要的附属器官之一，是解决这一问题的理想范例。毛囊经历生长期（生长期）、破坏期（退化期）和休止期（休止期）的周期。毛囊干细胞（HFSC）位于毛囊的永久性突起中，这种结构称为凸起。隆突期HFSC周期不频繁。在正常的体内平衡期间，HFSC仅在生长期的非常短暂的窗口中增殖，而在所有其他阶段期间保持静止。 HFSC也可以在受伤时被激活。 HFSC活性的失调导致严重的后果。 例如，脱发（脱发）和延迟的伤口愈合可能由HFSC的低效激活引起。相反，皮肤肿瘤，如基底细胞癌和鳞状细胞癌，可来源于HFSC过度增殖。干细胞的活动受到其微环境的严重影响，称为生态位。传统上，关于生态位的研究仅关注周围的异源细胞类型，即，细胞来自不同的谱系。最近的研究，包括我自己的发现的重要性，干细胞后代作为生态位组成部分，在几个脊椎动物和无脊椎动物干细胞系统，这是以前没有认识到的。在毛囊中，我的初步研究已经确定了两个重要的后代群体， HFSC增殖的调节剂。该提议要检验的中心假设是，来自HFSC后代的反馈调节对于HFSC的适当行为和活性至关重要。该假设将在本授权申请中通过以下实验进行测试：1）检查子代表达的候选信号，2）确定子代在生理和病理条件下对HFSC活化的贡献，和3）鉴定子代表达的调节HFSC的新功能因子。候选信号将在指导阶段进行调查。在独立阶段，将跟踪动态条件下子代的贡献以及子代表达的鉴定的新因子。成功完成所提出的实验将显着推进我们的理解的细胞类型和信号，调节HFSC增殖和静止。此外，这些拟议的研究将可能导致与异常干细胞活性相关的皮肤疾病的治疗方法的发展。我的长期职业目标是领导一个成功的，独立的，资金充足的实验室研究皮肤和干细胞生物学。 我的研究生和博士后培训到目前为止，我准备在技术和智力上开发严格的研究项目。这个职业发展奖和我提出的研究计划将进一步为我提供机会，扩大我在皮肤干细胞生物学和小鼠遗传学方面的知识，获得生物信息学分析，小鼠胚胎操作，基于图像的FACS分析的新技能，并进一步积累经验，以提高指导，演讲和写作技能，所有这些都是我作为一名独立研究人员取得成功的关键。 在指导阶段产生的试剂也将有助于建立我在独立阶段的研究计划。洛克菲勒大学及其邻近的两个机构，纪念斯隆-凯特琳癌症中心和威尔康奈尔医学院，提供了一个主要的研究环境和许多研讨会和课程，以支持我的研究和职业发展。我将与我的导师Elaine Fuchs博士，我的合作者Olivier Elemento博士以及纽约地区的皮肤和小鼠发育生物学社区不断互动。他们将一起评估我的进展，并提供批评或建议。总之，拟议的研究和职业发展计划将更好地为我的独立科学生涯做好准备，确保我实现我的长期职业目标，并使我能够为我们理解干细胞活性如何在稳态和疾病中调节做出持续贡献。

DESCRIPTION (provided by applicant): The long-term objective of this proposal is to understand how the activity of stem cells is properly regulated to maintain homeostasis and tissue integrity. The hair follicle, one of the important skin appendages, is an ideal paradigm to address this problem. Hair follicles undergo cycles of growth (anagen), destruction (catagen) and rest (telogen) phases. Hair follicle stem cells (HFSCs) are located in a permanent protrusion of the hair follicle, a structure known as the bulge. HFSCs in the bulge cycle infrequently. During normal homeostasis, HFSCs only proliferate in a very transient window of anagen, while remaining quiescent during all the other phases. HFSCs can also become activated upon wounding. Dis-regulation of HFSC activity results in severe consequences. For example, alopecia (hair loss) and delayed wound healing may arise from inefficient activation of HFSCs. On the contrary, skin tumors, such as basal cell carcinoma and squamous cell carcinoma, can derive from HFSC hyper-proliferation. Stem cell activity is heavily influenced by their microenvironment, known as the niche. Traditionally, studies about niche focus only on the surrounding heterologous cell types, i.e., cells originated from a different lineage. Recent studies including my own discover the importance of stem cell progeny as niche components in several vertebrate and invertebrate stem cell systems, which is previously unrecognized. In the hair follicle, my preliminary studies have identified two important progeny populations as critical regulators for HFSC proliferation. The central hypothesis to be tested by this proposal is that feedback regulation from HFSC progeny is crucial for the proper behavior and activity of HFSCs. This hypothesis will be tested in this grant application by experiments that: 1) examine candidate signals expressed by the progeny 2) determine the contributions of the progeny to HFSC activation under physiological and pathological conditions and 3) identify novel functional factors expressed by the progeny to regulate HFSCs. Candidate signals will be investigated during the mentored phase. The contributions of progeny under dynamic conditions as well as identified novel factors expressed by the progeny will be follow-up during the independent phase. Successful completion of the proposed experiments will significantly advance our understanding of the cell types and signals that regulate HFSC proliferation and quiescence. In addition, these proposed studies will potentially lead to the development of therapeutic treatments for skin disorders associate with aberrant stem cell activity. My long-term career goal is to lead a successful, independent, and well-funded laboratory studying skin and stem cell biology. My graduate and postdoctoral training up to date has prepared me technically and intellectually to develop rigorous research projects. This career development award and my proposed research plan will further provide me with opportunities to expand my knowledge in skin stem cell biology and mouse genetics, gain new skills in bioinformatics analysis, mouse embryo manipulation, image-based FACS analysis, and further accumulate experience to improve mentoring, presentation, and writing skills, all of which are critical to my fuure success as an independent researcher. The reagents generated during the mentored phase will also help to build up my research program in the independent phase. The Rockefeller University together with its two neighboring institutions, Memorial Sloan-Kettering Cancer Center and Weill Cornell Medical College, offer a prime research environment and many workshops and courses to support my proposed research and my career development. I will have constant interactions with my mentor Dr. Elaine Fuchs, my collaborator Dr. Olivier Elemento, and the skin and mouse developmental biology communities in the New York area. Together they will assess my progress and provide critique or advice. In summary, the proposed studies and career development plan will better prepare me for my independent scientific career, ensure that I achieve my long-term career goals, and allow me to make continuous contributions towards our understanding of how stem cell activity is regulated in homeostasis and disease.