Mechanisms Driving Metabolic Shifts in the Intestinal Epithelium

肠上皮细胞并不呈现统一的代谢状态。代谢变化伴随而来 成体干细胞-隐窝-绒毛动态平衡的转变。新陈代谢的变化也会发生在对伤害和 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来治疗 肠道的疾病和紊乱。这项提案的直接目标是定义监管机构 控制上皮细胞寿命期间代谢变化的机制。 OX-PHOS基因在肠道干细胞中高表达，在隐窝中低表达，在绒毛中高表达。 OX-PHOS基因的动态表达与上皮细胞的代谢转变相平行。然而， 在肠道上皮细胞转变过程中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，确定了有助于上皮新陈代谢的转录因子。 拟议研究的目标1将深入研究转录因子YY1是如何促进 驱动电子传输链的基因表达。我们将检验YY1调控的假设 增强子-启动子染色质环促进线粒体所需这些关键基因的表达 呼吸。我们还将测试YY1在肠道干细胞中的功能不同于其 子代在隐窝或在绒毛肠腺细胞。将使用最先进的表观基因组和蛋白质组分析 在新的鼠标模型的背景下。我们预计这些监管机制对推动 在组织损伤/再生过程中暴露在低氧环境中或在 致癌作用。因此，我们还将研究组织后再生灶中的这些调节机制。 损伤以辨别YY1是否控制伴随组织再生的代谢变化。 目标2将着眼于线粒体呼吸的一种重要能源--脂肪酸的调节 氧化。我们将测试HNF4转录因子促进脂肪酸氧化的假设以支持 肠道干细胞更新。代谢组学、表观基因组学和基于有机物的分析的组合将是 使用了新的老鼠模型。我们将进一步检验雌激素相关受体的假设 是HNF4的一个重要和新的伙伴因子，HNF4和ESRRA共同塑造了 肠道上皮对饮食脂肪变化的反应。据我们所知，这些研究将提供 肠道核心转录因子调控网络与代谢状态之间的第一个联系 肠梗性所必需的。饮食中过多的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相结合的领域向前推进 肠道上皮的作用机制。总而言之，这些研究将揭示新陈代谢转变是如何 在正常动态平衡期间以及在病理情况下(上皮)在肠道中进行调节 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).