Small intestinal PepT1 expression plays a critical role in maintaining intestinal homeostasis and in shaping the gut microbiota

PepT 1是质子寡肽转运蛋白（POT）超家族的成员， 转运二肽/三肽。我们的研究小组和其他人已经表明，PepT 1在上皮细胞中高度表达， 小肠，但在正常大肠的这些细胞中以低水平或不可检测的水平存在（1-8）。 我们以前的研究表明PepT 1的表达和转运活动有助于结肠炎和结肠炎 相关癌症（5，9）。最近，我们报道了这种膜转运蛋白的功能不是 仅限于其作为二-三肽转运蛋白的经典功能。例如，我们证明PepT 1 表达通过介导肠miRNA表达/分泌来帮助维持肠内稳态（10，48）。 总之，我们先前的研究表明，PepT 1可能与肠道内稳态有关， 在各种病因中，包括结肠炎和结肠炎相关癌症的病因。我们的新假设 小肠PepT 1的表达在维持肠道内环境稳定和 塑造肠道微生物群这项建议的最初目的是证明缺乏小肠 PepT 1表达将肠道微生物群塑造成抗炎微生物群， 预防结肠炎和结肠炎相关癌症。然后，我们将探讨小肠PepT 1的影响， 表达，并因此导致肠miRNA对肠粘膜稳态的失调。 最后，我们将研究微生物群是如何通过宿主miRNA的表达/分泌来调节的， 依赖于PepT 1在小肠中的表达，我们将定义操纵PepT 1的方法。 微生物组通过管理特定的miRNA。我们预计，计划中的工作将确定 小肠PepT 1的表达在维持肠道内稳态和塑造 肠道菌群拟议的研究还将促进治疗策略的发展 治疗肠道炎症

PepT1, which is a member of the proton oligopeptide transporter (POT) superfamily, is well known to transport di/tripeptides. Our group and others have shown that PepT1 is highly expressed in epithelial cells of the small intestine, but present at low or undetectable levels in such cells of the normal large intestine (1-8). We previously showed that the expression and transport activities of PepT1 contribute to colitis and colitis associated cancer (5, 9). More recently, we reported that the function of this membrane transporter is not restricted to its classical function as transporter of di-tripeptides. For example, we demonstrated that PepT1 expression helps maintain intestinal homeostasis by mediating intestinal miRNA expression/secretion (10, 48). Together, our prior studies revealed that PepT1 may be associated with intestinal homeostasis and implicated in various pathogeneses, including those of colitis and colitis associated cancer. Our novel overall hypothesis is that small intestinal PepT1 expression plays a critical role in maintaining intestinal homeostasis and in shaping the gut microbiota. The initial aim of this proposal is to demonstrate that a lack of small intestinal PepT1 expression shapes the gut microbiota into an anti-inflammatory microbiota that is implicated in preventing colitis and colitis associated cancer. We will then explore the effects of small intestinal PepT1 expression and consequently the intestinal miRNA dysregulation on the intestinal mucosal homeostasis. Finally, we will investigate how the microbiota is regulated by the expression/secretion of host miRNAs that depend on the expression of PepT1 in the small intestine, and we will define ways to manipulate the microbiome by administering specific miRNAs. We envisage that the planned work will identify the role played by small intestinal PepT1 expression plays a critical role in maintaining intestinal homeostasis and in shaping the gut microbiota. The proposed research will also facilitate the development of therapeutic strategies targeting intestinal inflammatory conditions.