Identification and Characterization of Melanocyte Stem Cells

描述(申请人提供)：这项拟议的研究旨在确定我们已经鉴定的黑素细胞干细胞(MSCs)的不同亚群如何被调节和维持在干细胞状态，并有助于色素再生。这项研究的基本原理是基于我们的发现，间充质干细胞不仅分布在小鼠毛囊(HF)中称为隆起的区域，也是毛囊的角质形成干细胞(KcSCs)的位置，而且还存在于次级毛胚(SHG)，这是一种位于毛乳头附近的端原或静止毛囊的临时结构。我们的实验室利用独特的转基因小鼠系统和荧光激活细胞分选(FACS)相结合的方法来分离和研究这两个存活状态的细胞亚群。我们研究的目的是确定这些MSC亚群中哪些具有更大的再生潜力，并描述这些不同亚群之间的相互关系和维持决定因素。为了实现这一目标，我们计划在体外和体内测试这些细胞亚群自我更新、保持静止的能力，并在以前未着色的活体HFs中再生色素沉着。这些研究将由我们开发的独特的双转基因小鼠品系DCT-H2BGFPki与FACS设施和其他核心资源相结合来完成，这些资源与我位于马里兰大学医学院生物化学和分子生物学系的研究实验室相关。这些研究的结果应该会对普通公众的医疗保健产生积极的影响。通过确定哪些小鼠MSC亚群在再生色素沉着方面最有效，我们将能够将这一知识应用于人类黑素细胞，分离或产生具有强大再生特性的人类细胞。这些细胞可以用来治疗正在脱色的白癜风患者，或者在愈合的伤口或疤痕中再生色素沉着。此外，干细胞与癌症有关，因为在干细胞中表观遗传抑制的基因更有可能在相应的癌细胞类型中被抑制。通过确定MSCs中关键黑素细胞和生长基因的表观遗传状态，我们可以揭示导致黑色素瘤发生发展中不可逆转基因抑制的分子机制，从而揭示特定来源的细胞如何促进这种特定恶性肿瘤的发展。

DESCRIPTION (provided by applicant): The proposed study is designed to determine how distinct subsets of melanocyte stem cells (MSCs) we have identified are regulated and maintained in the stem cell state and contribute to pigment regeneration. The rationale for the study is based upon our discovery that MSCs not only populate a region of the murine hair follicle (HF) termed the bulge, also the site of keratinocyte stem cells (KcSCs) of the HF, but also the secondary hair germ (SHG), a transient structure at the base of the telogen, or resting, HF adjacent to the dermal papilla. Our laboratory has developed methods to separate and study these two cell subsets in the viable state using a combination of a unique transgenic mouse system and fluorescence-activated cell sorting (FACS).The objectives of our studies are to determine which of these MSC subsets has greater regenerative potential, and to describe the interrelationship between and maintenance determinants of these distinct subsets. To realize this objective, we plan to test in vitro and in vivo the capacity of these cell subsets to self-renw, maintain quiescence, and also regenerate pigmentation in previously unpigmented living HFs. These studies will be accomplished a unique, bitransgenic mouse line we have developed, Dct-H2BGFPki, in combination with the FACS facility and other core resources associated with my research laboratory located in the Department of Biochemistry and Molecular Biology at the University of Maryland School of Medicine. The results of these studies should have a positive impact on the health care of the general public. By determining which murine MSC subsets are most effective at regenerating pigmentation, we will be able to apply that knowledge to human melanocytes, isolating or generating human cells with potent regenerative properties. These cells can be developed to treat patients with the depigmenting disease vitiligo or for regenerating pigmentation in healing wounds or scars. In addition, stem cells are related to cancer because genes repressed epigenetically in stem cells are more likely to be suppressed in the corresponding cancer cell type. By determining the epigenetic state of key melanocyte and growth genes in MSCs, we may highlight molecular mechanisms leading to irreversible gene repression in melanoma developing, thereby revealing how particular cells of origin contribute to the development of this particular malignancy.