Hair follicle bulge cells in tumorigenesis and alopecia

描述(申请人提供)：这个项目的长期目标是更好地了解上皮干细胞生物学。上皮干细胞负责表皮、毛囊和角膜等自我更新组织的再生。我们最初在毛囊的隆起中发现了可能的上皮干细胞。然后我们分离了一个角蛋白15启动子，该启动子针对转基因小鼠中的隆起细胞。K15启动子可用于毛囊干细胞的分离、谱系分析和分子鉴定。我们发现，凸起细胞具有干细胞的特性，分离的凸起细胞可以重建毛囊、表皮和皮脂腺。我们现在已经确定了一些基因，我们假设这些基因保持干细胞的表型。在这项拨款申请中，我们将： 1.通过以下方法评估隆起细胞中上调的基因对维持毛囊干细胞表型是否重要： A.在转基因小鼠的非毛囊干细胞中过度表达候选基因，然后测试这些细胞是否表现为毛囊干细胞。 B.利用我们的Kl5CrePrl小鼠在隆起细胞中删除或过度表达特定基因，从而阻断特定于隆起细胞的候选基因通路。 2.通过以下方式确定端原膨大细胞中下调的基因是否参与干细胞激活和/或谱系决定： A.使用RU486诱导系统产生可诱导的转基因小鼠，其中候选基因在珠状细胞中过表达，以及 B.使用K1SCrePR L小鼠，删除凸起细胞及其后代中特定的候选“凸起激活”或谱系决定基因。 3.开发分离和鉴定人毛囊干细胞的方法。 A.我们将确定在小鼠肿胀中发现的基因是否也在人类肿胀中表达。 B.我们将根据细胞表面蛋白的表达模式来描述小鼠和人类毛囊内的毛囊干细胞和祖细胞。这些毛囊内不同的细胞亚群将通过荧光激活细胞分选得到分离，并将识别它们的干细胞性质、基因表达模式和功能特征。 脱发、毛干紊乱、基底细胞癌、毛囊肿瘤或慢性伤口的患者可能会从这项研究中受益。

DESCRIPTION (provided by applicant): The long term goal of this project is to better understand epithelial stem cell biology. Epithelial stem cells are responsible for the regeneration of self-renewing tissues such as epidermis, hair follicle, and cornea. We originally identified putative epithelial stem cells in the bulge of the hair follicle. We then isolated a keratin 15 promoter that targets bulge cells in transgenic mice. The K15 promoter allowed for the isolation, lineage analysis and molecular characterization of hair follicle stem cells. We showed, that bulge cells have properties of stem cells, and isolated bulge cells can reconstitute hair follicles, epidermis and sebaceous glands. We have now identified a number of genes which we hypothesize maintain the stem cell phenotype. In this grant application we will: 1. evaluate whether genes upregulated in the bulge cells are important for maintaining the hair follicle stem cell phenotype by: a. overexpressing candidate genes in non-hair follicle stem cells of transgenic mice, and then testing whether these cells behave as hair follicle stem cells. b. blocking candidate gene pathways specifically in the bulge cells using our Kl5CrePrl mice to delete or overexpress genes specifically in the bulge cells. 2. determine if genes downregulated in telogen bulge cells are involved in stem cell activation and/or lineage determination by: a. generating inducible transgenic mice in which candidate genes are over-expressed in bulgecells using an RU486 inducible system, and b. deleting candidate "bulge activation" or lineage determining genes specifically in bulge cells and their progeny using theKlSCrePR l mice. 3. develop means for isolating and characterizing human hair follicle stem cells. a. We will establish whether genes identified in mouse bulge are also expressed in human bulges. b. We will delineate hair follicle stem and progenitor cells within both the mouse and human hair follicle based on cell surface protein expression patterns. These distinct subpopulations of cells within the hair follicle will be isolated by fluorescent activated cell sorting, and their stem cell nature, gene expression patterns and functional characteristics will be discerned. Patients with alopecia, hair shaft disorders, basal cell carcinoma, hair follicle tumors, or chronic wounds could potentially benefit from this research.