Transcriptional regulation of esophageal stem cell gene signature

组织的维持是由稀有的细胞保证的，这些细胞寿命长，可以自我更新，并产生组织的所有细胞类型，称为干细胞。干细胞保证在正常条件下产生新的细胞，以补偿细胞死亡或终末分化造成的细胞损失，以及组织再生过程中的损失。干细胞在皮肤和消化道等周转率高的组织中尤为重要。食道内有一层称为复层鳞状上皮的多层上皮，它形成了一道紧密的屏障，保护组织免受食管腔内严酷环境的影响。在我们的研究之前，干细胞在食道上皮中的存在一直存在争议。我们最近鉴定并鉴定了第一批小鼠食道干细胞。这些细胞被角蛋白15(Krt15)标记，并表现出与干细胞群体一致的特征，如自我更新和再生能力。Krt15食道干细胞的鉴定和描述极大地改变了我们对食道上皮生物学的理解。尽管如此，我们仍然对食道上皮中驱动细胞命运决定和干细胞维持的转录调控知之甚少。这个项目的长期目标是确定参与食道干细胞维持的转录网络的性质。我们已经确定了Krt15食道干细胞的转录图谱，并观察到与Krt15-细胞相比，Krt15细胞中Ascl2基因转录大量上调。ASCL2是一种与其他组织的自我更新和细胞增殖相关的转录因子。因此，短期目标是研究转录因子ASCL2作为一个潜在的候选转录调控食道干细胞基因信号和食道上皮内稳态的影响。我们将通过两个具体的目标来实现这一目标：*1)分析Ascl2缺失对食道上皮细胞自我更新的影响。*2)确定食道上皮细胞中ASCL2的结合伙伴和基因靶点。*我们将使用几种3D细胞培养模型，结合转录组学和RNA基因组学方法来实现这些目标。总之，通过剖析ASCL2在食道细胞自我更新中的作用以及ASCL2这一作用背后的转录机制，我们独特的研究计划将提高我们对食道干细胞生物学的了解。

Tissue maintenance is assured by rare cells that are long-lived, can self-renew and give rise to all cell types of a tissue, known as stem cells. Stem cells assure the production of new cells in normal condition to compensate for cell loss due to cell death or terminal differentiation, and also during tissue regeneration. Stem cells are particularly important in tissues with high turnover such as the skin and the digestive tract. The esophagus is lined by a multilayered epithelium called stratified squamous epithelium which forms a tight barrier protecting the tissue from the austere environment that can be found in the esophageal lumen. The existence of stem cells in the esophageal epithelium remained controversial until our study. We recently identified and characterized the first population of mouse esophageal stem cells. These cells are marked by Keratin 15 (Krt15) and display characteristics consistent with a stem cell population such as self-renewal and regenerative capacity. The identification and description of Krt15+ esophageal stem cells have dramatically changed our understanding of esophageal epithelial biology. Nonetheless, we still understand little about the transcriptional regulation that drives cell fate decision and stem cell maintenance in the esophageal epithelium.****** The long-term goal of this project is to determine the nature of the transcriptional network involved in the maintenance of esophageal stem cells. We have determined the transcriptional profile of Krt15+ esophageal stem cells and observed a massive upregulation of Ascl2 gene transcript in Krt15+ cells when compared to Krt15- cells. ASCL2 is a transcription factor associated with self-renewal and cell proliferation in other tissues. Therefore, the short-term objective is to investigate the impact of transcriptional factor ASCL2 as a potential candidate for transcriptional regulation of the esophageal stem cell gene signature and esophageal epithelial homeostasis. We will pursue this objective through two specific aims:******1) Analyze the impact of Ascl2 loss on self-renewal of esophageal epithelial cells.***2) Determine ASCL2 binding partners and gene targets in esophageal epithelial cells. ******We will use several 3D cell culture models in combination with transcriptomics and RNomics approaches to accomplish these aims. Altogether, by dissecting the role of ASCL2 on esophageal cell self-renewal and the transcriptional mechanisms underlying this role of ASCL2, our unique research program will improve our knowledge on esophageal stem cell biology.**