Cell Fate Regulation in Esophageal Progenitor Cells

项目摘要 Barrett食管和食管小细胞癌的特征是鳞状细胞的丢失 同时获得其他细胞的命运。到目前为止，这些疾病的有效治疗选择在一定程度上受到限制。 这是由于对驱动初始细胞命运变化的分子机制的不完全理解。这 应用程序将解决转录因子p63如何指导鳞状细胞分化程序和保障 食管基底祖细胞来自神经内分泌细胞定型。 我们和其他人已经证明，p63的缺失导致复层鳞状上皮的消失， 在发育中的食道里然而，p63如何调节食管祖细胞的细胞命运决定 仍然是未知的。令人惊讶的是，我们发现p63缺失导致广泛的神经内分泌失调， 食管的分化。此外，p63表达的丢失也见于小细胞癌， 食道抑制关键的表观遗传沉默因子EZH 2重新激活p63表达， 神经内分泌细胞，这是伴随着收购的鳞状细胞的命运。因此我们假设 表观遗传学调节的p63表达抑制神经内分泌，同时促进鳞状细胞 在食管中的分化程序。三个具体的目标是制定测试的假设。目标1将 测试p63在细胞命运决定中所起的作用是否是同种型特异性的并且在人类中是保守的 食管祖细胞（EPCs）。我们将把联合收割机小鼠遗传模型和人类多能干细胞 差异化是为了实现这一目标。目的2将确定p63介导的转录程序， EPC的规格。我们将使用多种表观基因组测定，包括ChIP-seq和ATAC-seq，以确定 p63下游靶点在全基因组水平。我们还将使用生物化学分析来测试候选基因 参与细胞命运转变，其可能被p63结合并在功能上受p63调节。目标3将决定 p63基因沉默对神经内分泌定向的影响及其机制。在这个目标中，我们将研究如何 在异常细胞命运定型过程中，p63表达受表观遗传调控机制调节，因此 确定恢复鳞状分化程序的策略。结合我们在鼠标方面的共同专业知识 遗传学，细胞生物学，染色质生物学和表观基因组学，这项工作将提供新的机制见解， 为神经内分泌病变的治疗提供了新的途径。

Project Summary Barrett’s esophagus and small cell carcinoma in the esophagus are characterized by the loss of squamous cell identity while gaining other cell fates. Thus far effective treatment options for these diseases are limited in part due to an incomplete understanding of the molecular mechanisms driving the initial cell fate changes. This application will address how the transcription factor p63 directs the squamous differentiation program and safeguards esophageal basal progenitor cells from neuroendocrine cell commitment. We and others have demonstrated that loss of p63 leads to the abrogation of the stratified squamous epithelium in the developing esophagus. However, how p63 regulates cell fate determination of esophageal progenitor cells remains largely unknown. Surprisingly, we found that p63 deletion results in extensive neuroendocrine differentiation in the esophagus. Moreover, loss of p63 expression was also observed in small cell carcinoma of the esophagus. Inhibition of the key epigenetic silencing factor EZH2 re-activates p63 expression in neuroendocrine cells, which is accompanied by the acquisition of squamous cell fate. We therefore hypothesize that epigenetically regulated p63 expression suppresses neuroendocrine while promoting the squamous cell differentiation program in the esophagus. Three specific aims are formulated to test the hypothesis. Aim 1 will test whether the role played by p63 in cell fate determination is isoform-specific and conserved in human esophageal progenitor cells (EPCs). We will combine mouse genetic models and human pluripotent stem cell differentiation to address this Aim. Aim 2 will determine p63-mediated transcriptional program during the specification of EPCs. We will use multiple epigenomic assays including ChIP-seq and ATAC-seq to determine p63 downstream targets at the genome-wide level. We will also use biochemistry assays to test candidate genes implicated in cell fate transition that are potentially bound and functionally regulated by p63. Aim 3 will determine the mechanism and impact of p63 silencing on neuroendocrine commitment. In this Aim we will investigate how p63 expression is modulated by epigenetic regulatory mechanisms during aberrant cell fate commitment, thus identifying strategies to restore the squamous differentiation program. Combining our joint expertise on mouse genetics, cell biology, chromatin biology and epigenomics, this work will provide novel mechanistic insights into esophageal cell fate regulation and offer new approaches to treat neuroendocrine lesions.