Defining the molecular mechanisms driving intestinal epithelial cell specification

肠上皮是一个动态系统，在整个生物体生命过程中不断快速地再生。这种上皮组织在隐窝和绒毛区室中，具有不同的细胞群和功能。肠隐窝含有上皮干细胞，周围是分化的paneth细胞。这些后一种细胞表达促进生长和细胞保护肽，以确保干细胞产生最佳的祖细胞。肠绒毛包含分化的上皮细胞亚型，包括肠细胞、杯状细胞和肠内分泌细胞。尽管在过去的几年里已经收集了一些线索，关于在这种特殊情况下前上皮细胞规范和维持所需的分子机制的本质，但所涉及的确切调控电路仍然没有很好地定义。此次发现基金的续期将继续进行这一研究项目，并建议在未来五年内整合一组蛋白质之间的互动转录网络，其中包括我们过去几年研究过的一些蛋白质。更准确地说，我们提出的工作将集中在GATA4转录因子上，我们最近已经确定了它的特异性新的肠上皮细胞功能，随着其他相关转录调节因子的发现，它的综合转录和生物学影响。我们还打算利用我们最近在实验室优化的创新系统模型。该生物系统由离体生长的小型上皮肠道组成，可以很好地概括肠上皮的增殖和细胞分化。本研究计划旨在确定在干细胞和分化细胞中易调控肠上皮转录组的GATA4蛋白复合物的性质，并确定GATA4与大多数相关的相互作用转录调节因子结合的全局肠上皮遗传靶标。我们希望这些策略将为上皮干细胞和分化细胞中上皮细胞特异性转录相互作用组的性质提供重要信息。这将使我们更好地理解肠上皮细胞规范中重要的调节因子的性质，并可能提供新的长期靶向策略，以替代产生独特的肠道上皮细胞富集和特异性亚型的培养集，这些模型仍有待优化。

The intestinal epithelium is a dynamic system that constantly and rapidly regenerates throughout theorganism life. This epithelium is organized in crypt and villus compartments harboring distinct cellpopulations and functions. Intestinal crypts contain epithelial stem cells surrounded by differentiatedPaneth cells. These latter cells express growth-promoting and cell-protective peptides to ensureoptimal production of progenitors from the stem cells. Intestinal villi contain differentiated subtypesof epithelial cells including enterocytes, goblet and enteroendocrine cells. Although some clues havebeen collected over the past years on the nature of the molecular mechanisms that are required forepithelial cell specification and maintenance in this particular context, the exact regulatory circuitinvolved is still not well defined. This renewal of Discovery Grant intends to pursue this program ofresearch and proposes to integrate, over the next five years, the interactive transcriptional networkbetween a set of proteins including some of which we have studied over the past years. Moreprecisely, our proposed work will focus on the GATA4 transcription factor, for which we haverecently identified specific novel intestinal epithelial cell functions, toward its integratedtranscriptional and biological impact with the discovery of other relevant transcriptional regulators.We also intend to take advantage of an innovative system model that we have recently optimized inthe laboratory. This biological system consists of mini epithelial guts growing ex vivo that perfectlyrecapitulate proliferation and cytodifferentiation of the intestinal epithelium. This research programwill aim to define the nature of GATA4 protein complexes susceptible to regulate the intestinalepithelial transcriptome in stem and differentiated cells and to define the global intestinal epithelialgenetic targets of GATA4 in combination to most relevant identified interacting transcriptionregulator(s). It is our hope that these strategies will provide crucial information on the nature of theepithelial cell specific transcriptional interactome(s) in both epithelial stem and differentiated cells.This will allow a better understanding of the nature of regulators important for intestinal epithelial cellspecification and perhaps provide novel long-term targeting strategies to alternatively produceunique culture sets of enriched and specific subtypes of intestinal epithelial cells, models that stillawait to be optimized.