Intestinal Stem/progenitor Cell Potency and Competence

描述(由申请人提供)： 胃肠道上皮是成体组织中增殖/再生能力最强的组织之一，表明存在肠道干细胞(ISC)池。到目前为止，由于以下因素，在鉴定、分离和研究自我更新的多潜能肠道干细胞方面的进展受到阻碍：a)缺乏特定的肠道干细胞标志物，b)对肠道干细胞用于在自我维持或分化之间选择的分子机制缺乏充分的了解，以及c)缺乏分离肠道干细胞并在分子和生理水平上对其进行表征的方法。鉴定肠道干细胞和确定肠道干细胞/祖细胞潜能的分子机制对于了解正常和异常的肠道功能都是至关重要的。最近，SOX转录因子家族被认为与调节干细胞或祖细胞的潜能和能力有关--即自我更新和分化为组织/器官的所有细胞类型的能力。已在成人小肠和结肠中检测到几个SOX家族成员的mRNAs。除SOX9外，SOX因子在肠道中的细胞定位和作用仍很不清楚。SOX9被定位在被广泛认为是小肠干细胞的位置。SOX9在隐窝底部的广泛表达模式表明它是干细胞和祖细胞的生物标记物。我们最近已经证明，SOX4和SOX7在小肠中的表达更多地限于小肠干细胞巢中的一小部分细胞。因此，本研究的中心假设是，特定的SOX蛋白是肠道干细胞和祖细胞隐窝细胞的生物标志物，在维持干/祖细胞的能力和能力方面发挥关键作用。为了验证这一假说，我提出了以下目标：1)建立SOX家族成员在干细胞和祖细胞中的表达谱；2)使用染色质免疫沉淀(CHIP)和一种新的Sox9EGFP报告鼠来定义SOX9的功能角色。3)建立红色荧光蛋白/谱系双重标记小鼠模型(Sox4Tomato/CreERT2)，以检测表达Sox4[SIC]的细胞的“严格性”。这些研究对提高我们对肠道损伤和修复、先天性疾病和癌症的理解和治疗至关重要。

DESCRIPTION (provided by applicant): The gastrointestinal epithelium is one of the most proliferative/regenerative tissues in adult organisms pointing to the existence of an intestinal stem cell (ISC) pool. Progress towards identification, isolation, and study of a self-renewing, multipotential intestinal stem cell has been hindered thus far due to the following factors: a) the lack of specific intestinal stem cell markers, b) the lack of a full understanding of the molecular mechanisms that the intestinal stem cell uses to choose between self-maintenance or differentiation, and c) a lack of methods to isolate intestinal stem cells and characterize them at the molecular and physiologic level. Identifying the intestinal stem cell and defining the molecular mechanisms that underlie intestinal stem/progenitor cell potency is critical to the understanding of both normal and dysregulated intestinal function. Recently, the SOX-family of transcription factors has been implicated in modulating stem or progenitor cell potency and competence - the ability to self-renew and differentiate into all cell types of the tissue/organ. The mRNAs for several SOX family members have been detected in both the adult small intestine and colon. With the exception of SOX9 the cellular localization and role of SOX factors in the intestine remain largely unknown. SOX9 has been localized to what is widely thought to be the stem cell niche in the small intestine. The broad expression pattern of SOX9 at the base of the crypt suggests it is a biomarker of both stem and progenitor cells. We have recently demonstrated that SOX4 and SOX7 expression is more restricted in small intestine to a very small population of cells in the small intestine stem cell niche. Thus, the central hypothesis of this study is that specific SOX proteins are biomarkers of stem and progenitor crypt cells in the intestine and play a critical role in maintaining stem/progenitor cell potency and competence. To test this hypothesis I propose the following aims: 1) To establish an expression profile for SOX family members in stem and progenitor cells, 2) To use chromatin immunoprecipitation (ChIP) and a novel Sox9EGFP reporter mouse to define the functional role of SOX9. 3) To develop a dual purpose red- fluorescent protein/lineage marking mouse model (Sox4Tomato/CreERT2) to assay 'sternness' of Sox4 [sic] - expressing cells. These studies are critical to enhance our understanding and treatment of intestinal injury and repair, congenital disorders, and cancer.