Decoding LRH-1 Activity in Gut Regeneration and Differentiation

项目总结/摘要 背景资料： 十多年来，人们已经知道肠道中的初级上皮干细胞，这导致了重要的 观察上皮更新和损伤恢复。这些基础研究表明， 肠上皮细胞是一个平衡的连续体之间的干在隐窝基地和分化， 粘膜表面，复杂的信号网络影响分化的干细胞和命运， 祖细胞一些研究小组现在已经表明，肠道干细胞和/或广泛的 上皮损伤可以通过祖细胞的去分化来修复。因此， 干性和分化可以通过尚未确定的分子机制来改变。 我们发现，核受体肝受体同源物-1（LRH-1; NR 5A 2）对这两种细胞都是必不可少的。 干细胞维持和指导高度特化的肠内分泌细胞谱系的分化。 因此，这种不寻常的转录因子具有促进干细胞和细胞分化的双重作用，使其 一个有吸引力的目标，阐明机制负责肠上皮更新和愈合。 方法： 在本申请中，我们将1）确定LRH-1对上皮修复和干细胞恢复的贡献， 肠炎模型，2）确定LRH-1的SUMO化如何调节干细胞和祖细胞中的受体功能 细胞，和3）确定和验证细胞特异性肠道LRH-1“靶组”。我们将通过以下方式实现这一目标： 谱系追踪小鼠模型的使用和肠道类器官平台的新实现。 在成功完成我们的目标后，我们将机械地评估一个 可药用核受体1）平衡干细胞更新，分化和受损细胞的恢复 2）提供了第一次详细评估SUMO化的LRH-1在肠道中，和3）产生了一个 真正的LRH-1肠道靶点，这将是非常宝贵的受体药物开发。 目标： 本提案旨在扩大我资助的K 08调查期间发现的一个关键发现， 推进我们对肠道如何在正常和正常发育过程中平衡干性与分化的机械理解， 病态的国家这项工作的基础是我们的假设，LRH-1是不同的调制内独特的 干细胞和祖细胞中的细胞环境，以驱动多种基因程序，同时支持细胞 更新和专门的细胞分化。我们的实验旨在最大限度地利用 肠上皮生理学和核受体生物学的非凡融合由LRH-1框架。

Project Summary/Abstract Background: The primary epithelial stem cell in the intestine has been known for over a decade, leading to important observations in epithelial renewal and injury recovery. These fundamental studies have demonstrated that the intestinal epithelium is a balanced continuum between stemness in the crypt base and differentiation towards the mucosal surface, with complex signaling networks influencing stemness and fate of the differentiating progenitor cells. Several groups have now shown that destruction of intestinal stem cells and/or extensive epithelial damage can be repaired by the dedifferentiation of progenitor cells. Thus, the balance between stemness and differentiation can be tipped by as yet undefined molecular mechanisms. We discovered that the nuclear receptor Liver Receptor Homolog-1 (LRH-1; NR5A2) is essential for both stem cell maintenance and for directing differentiation of the highly specialized enteroendocrine cell lineage. Therefore, this unusual transcription factor has dual roles promoting stemness and cell differentiation, making it an attractive target for elucidating the mechanisms responsible for gut epithelial renewal and healing. Approach: In this application, we will 1) determine the contribution of LRH-1 to epithelial repair and stem cell restitution in enteritis models, 2) determine how SUMOylation of LRH-1 modulates receptor function in stem and progenitor cells, and 3) determine and validate the cell-specific gut LRH-1 “targetome.” We will accomplish this through the use of lineage-traced mouse models and novel implementations of the intestinal organoid platform. Following successful completion of our aims, we will have mechanistically evaluated the contribution of a druggable nuclear receptor to 1) balancing stem cell renewal, differentiation, and restitution of damaged epithelium 2) provided the first ever detailed evaluation of SUMOylated LRH-1 in the gut, and 3) generated a bona fide LRH-1 gut targetome that will be invaluable for receptor drug development. Goals: This proposal is designed to expand upon a key finding uncovered during my funded K08 investigation and advance our mechanistic understanding of how the gut balances stemness vs differentiation during normal and diseased states. Underlying this work is our hypothesis that LRH-1 is differentially modulated within unique cellular contexts in stem and progenitor cells to drive diverse gene programs simultaneously supporting cell renewal and specialized cell differentiation. Our experiments are designed to maximally exploit the extraordinary confluence of intestinal epithelial physiology and nuclear receptor biology framed by LRH-1.