Mechanisms Driving Metabolic Shifts in the Intestinal Epithelium

肠上皮细胞没有表现出统一的代谢状态。代谢变化伴随着 在成体茎-隐窝-绒毛稳态期间的过渡。代谢变化也发生在对损伤的反应中， 结肠癌这项研究的长期目标是确定有针对性的代谢调节过程，以治疗 肠道的疾病和紊乱。该提案的直接目标是定义监管 在上皮细胞寿命期间控制代谢转变的机制。 OX-PHOS基因表达水平在肠干细胞中高，在隐窝中低，在绒毛中最高。 OX-PHOS基因的动态表达与上皮的代谢转变平行。但 在肠上皮细胞转变期间调节细胞代谢的机制尚不清楚。我们 已经产生了新的小鼠模型，确定有助于上皮代谢的转录因子。 拟议研究的目标1将深入研究转录因子YY 1如何促进 驱动电子传递链的基因的表达。我们将检验YY 1调节 增强子-启动子染色质环，以促进线粒体所需的这些关键基因的表达， 呼吸我们还将检验YY 1功能在肠干细胞中与在肠干细胞中不同的假设。 在隐窝或绒毛肠细胞中的后代。将采用最先进的表观基因组学和蛋白质组学分析 in the context上下文of novel新mouse小鼠models模型.我们预计这些监管机制对于推动 在组织损伤/再生期间暴露于低氧环境时发生的代谢变化， 肿瘤发生因此，我们也将研究这些调控机制，在再生灶后，组织 损伤来辨别YY 1是否控制伴随组织再生的代谢变化。 目标2将着眼于调节线粒体呼吸的一个重要能量来源-脂肪酸 氧化我们将检验HNF 4转录因子促进脂肪酸氧化的假设，以支持 肠干细胞更新代谢组学、表观基因组学和基于类器官的测定的组合将是 使用新的小鼠模型。我们将进一步检验雌激素相关受体 是HNF 4重要和新的伴侣因子，HNF 4和ESRRA一起塑造了 肠上皮细胞对饮食脂肪变化的反应。据我们所知，这些研究将提供 核心肠转录因子调控网络和代谢状态之间的第一个联系 肠道干燥所需的过量的膳食脂肪会增加肥胖和结肠癌的风险。我们的研究将 将饮食和代谢物如何与转录调控交叉联系起来， 肠上皮的机制。总之，这些研究将揭示代谢转换是如何发生的。 在正常稳态期间以及在病理情况下（上皮 再生或在高脂肪饮食下）。

Cells of intestinal epithelium do not exhibit a uniform metabolic state. Metabolic shifts accompany transitions during adult stem-crypt-villus homeostasis. Metabolic shifts also occur in response to injury and in colon cancer. The long term goal of this research is to define targetable metabolic regulatory processes to treat diseases and disorders of the intestine. The immediate goal of this proposal is to define the regulatory mechanisms that govern metabolic shifts during the epithelial cell lifespan. OX-PHOS gene expression levels are high in intestinal stem cells, low in crypts, and highest in villus. Dynamic expression of OX-PHOS genes parallels the metabolic transitions of the epithelium. However, the mechanisms regulating cellular metabolism during epithelial cell transitions in the intestine are unclear. We have generated new mouse models that identify transcription factors contributing to epithelial metabolism. Aim 1 of the proposed studies will drill down to identify how the transcription factor, YY1, promotes expression of genes that drive the electron transport chain. We will test the hypothesis that YY1 regulates enhancer-promoter chromatin looping to promote expression of these key genes required for mitochondrial respiration. We will also test the hypothesis that YY1 function differs in intestinal stem cells versus in their progeny in crypts or in villus enterocytes. State-of-the-art epigenomic and proteomic assays will be employed in the context of novel mouse models. We expect these regulatory mechanisms are important to drive metabolic shifts that occur upon exposure to low oxygen environments during tissue damage/regeneration or in oncogenesis. Therefore, we will also investigate these regulatory mechanisms in regenerative foci after tissue damage to discern whether YY1 controls the metabolic shifts that accompany tissue regeneration. Aim 2 will look at regulation of an important energy source for mitochondrial respiration – fatty acid oxidation. We will test the hypothesis that HNF4 transcription factors promote fatty acid oxidation to support intestinal stem cell renewal. A combination of metabolomics, epigenomics, and organoid-based assays will be employed, using novel mouse models. We will further test the hypothesis that the Estrogen-Related Receptor is an important and novel partner factor of HNF4, and that together, HNF4 and ESRRA shape the response of the intestinal epithelium in response to a change in dietary fat. To our knowledge, these studies would provide the first link between the core intestinal transcription factor regulatory networks and the metabolic state required for intestinal stemness. Excess dietary fat increases risk for obesity and colon cancer. Our studies will move the field forward in linking how diet and metabolites can intersect with the transcriptional regulatory mechanisms of the intestinal epithelium. Together, these studies will reveal how metabolic transitions are regulated in the intestine during normal homeostasis, as well as under pathological situations (epithelial regeneration or under high-fat diet).