Defining the molecular mechanisms driving intestinal epithelial cell specification

肠上皮细胞是一个动态系统，在整个生物体的生命周期中不断快速再生。这种上皮组织在隐窝和绒毛隔室中，具有不同的细胞群和功能。肠隐窝含有上皮干细胞，周围是分化的潘氏细胞。这些后一种细胞表达生长促进和细胞保护肽，以确保从干细胞最佳地产生祖细胞。肠绒毛含有分化的上皮细胞亚型，包括肠上皮细胞、杯状细胞和肠内分泌细胞。虽然在过去的几年里已经收集了一些线索，在这种特定的背景下，上皮细胞的规格和维护所需的分子机制的性质，涉及的确切的调节电路仍然没有很好地定义。发现补助金的更新旨在继续这项研究计划，并建议在未来五年内整合一组蛋白质之间的相互作用转录网络，包括我们过去几年研究的一些蛋白质。更确切地说，我们提出的工作将集中在GATA 4转录因子，我们最近已经确定了特定的新的肠上皮细胞功能，对它的综合转录和生物学影响与其他相关转录调节因子的发现。我们还打算利用我们最近在实验室中优化的创新系统模型。该生物系统由离体生长的微型上皮肠组成，其完美地再现了肠上皮的增殖和细胞分化。该研究计划旨在确定GATA 4蛋白复合物的性质，该蛋白复合物易于调节干细胞和分化细胞中的肠上皮转录组，并确定GATA 4与最相关的已鉴定相互作用转录调节因子组合的全球肠上皮遗传靶点。我们希望这些策略将提供关于上皮干细胞和分化细胞中上皮细胞特异性转录相互作用物组的性质的关键信息。这将允许更好地理解对肠上皮细胞特化重要的调节剂的性质，并可能提供新的长期靶向策略，以替代地产生肠上皮细胞的富集和特定亚型的独特培养物组，这些模型仍有待优化。

The intestinal epithelium is a dynamic system that constantly and rapidly regenerates throughout the organism life. This epithelium is organized in crypt and villus compartments harbouring distinct cell populations and functions. Intestinal crypts contain epithelial stem cells surrounded by differentiated Paneth cells. These latter cells express growth-promoting and cell-protective peptides to ensure optimal production of progenitors from the stem cells. Intestinal villi contain differentiated subtypes of epithelial cells including enterocytes, goblet and enteroendocrine cells. Although some clues have been collected over the past years on the nature of the molecular mechanisms that are required for epithelial cell specification and maintenance in this particular context, the exact regulatory circuit involved is still not well defined. This renewal of Discovery Grant intends to pursue this program of research and proposes to integrate, over the next five years, the interactive transcriptional network between a set of proteins including some of which we have studied over the past years. More precisely, our proposed work will focus on the GATA4 transcription factor, for which we have recently identified specific novel intestinal epithelial cell functions, toward its integrated transcriptional 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 in the laboratory. This biological system consists of mini epithelial guts growing ex vivo that perfectly recapitulate proliferation and cytodifferentiation of the intestinal epithelium. This research program will aim to define the nature of GATA4 protein complexes susceptible to regulate the intestinal epithelial transcriptome in stem and differentiated cells and to define the global intestinal epithelial genetic targets of GATA4 in combination to most relevant identified interacting transcription regulator(s). It is our hope that these strategies will provide crucial information on the nature of the epithelial 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 cell specification and perhaps provide novel long-term targeting strategies to alternatively produce unique culture sets of enriched and specific subtypes of intestinal epithelial cells, models that still await to be optimized.