Identification and Characterization of Melanocyte Stem Cells

描述（由申请人提供）：拟议的研究旨在确定我们已经确定的黑色素细胞干细胞（MSCs）的不同亚群如何被调节和维持在干细胞状态并促进色素再生。这项研究的基本原理是基于我们的发现，MSCs不仅填充了小鼠毛囊（HF）的一个称为凸起的区域，也是HF的角化细胞干细胞（KcSCs）的位置，而且还填充了次级毛胚（SHG），这是一个位于休止期或休息期HF底部的短暂结构，靠近真皮乳头。我们的实验室已经开发出分离和研究这两种细胞亚群的方法，使用独特的转基因小鼠系统和荧光激活细胞分选（FACS）的组合。我们研究的目的是确定哪些MSC亚群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的自我更新能力，保持沉默，并在先前未着色的活hf中再生色素沉着。这些研究将利用我们开发的一种独特的双转基因小鼠系Dct-H2BGFPki，结合FACS设备和我位于马里兰大学医学院生物化学与分子生物学系的研究实验室的其他核心资源来完成。这些研究的结果应该对公众的医疗保健产生积极的影响。通过确定哪些小鼠间充质干细胞亚群在再生色素沉着方面最有效，我们将能够将这些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。这些细胞可用于治疗白癜风患者的脱色性疾病，或用于愈合伤口或疤痕的再生色素沉着。此外，干细胞与癌症有关，因为在干细胞中被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，我们可以突出导致黑色素瘤发展中不可逆基因抑制的分子机制，从而揭示特定的起源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.