hPepT1 in Intestinal Inflammation

项目摘要 炎症性肠病(IBD)是一种慢性消化道炎症性疾病， 一个不确定的病因。目前，IBD的治疗仅限于5-氨基水杨酸酯， 皮质类固醇和免疫抑制剂，包括硫唑嘌呤和6-巯基嘌呤。 因为具有可接受的毒性和副作用的特效性和根治性治疗是 缺乏这一点，仍然需要开发有效的治疗方法。 对本应用程序具有重要意义的是我们来自先前研究的发现，该研究 证明细菌产物，如fMLP和MDP，可以通过 肠上皮寡肽转运蛋白PepT1。一旦被吸收到细胞质中，这些小的 细菌肽会引发炎症反应。这些细菌肽还可以相互作用 直接与免疫细胞结合。由于包括巨噬细胞在内的免疫细胞也表达PepT1， 它们有能力摄取细小的细菌肽，然后与NBS相互作用- 细胞内受体LRR家族(例如，NOD2)，介导细胞内识别 微生物及其产品。因此，连同在 上皮水平，免疫系统细胞中的这些小细菌肽可能导致 导致组织损伤的炎性级联反应。 我们的总体假设是PepT1通过以下方式在调节免疫反应中发挥关键作用 作为细菌产品的门户。这项提案的最初目的是调查 诱导结肠上皮细胞表达PepT1。其次，我们将调查 利用嵌合小鼠在肠道炎症中免疫细胞表达PepT1。最后，PepT1将 被用于靶向抗炎三肽，KPV，以炎症的结肠上皮和 免疫细胞。 该项目将在体外实验中涉及多种生化和分子方法 和活体水平。拟议的研究将产生新的见解，这将是设计的关键 以及改善肠道炎症状况的治疗策略的发展， 包括IBD。 美国有100多万成年人和儿童患有IBD。新疗法 基于对IBD发病机制的更好理解的策略将改善临床 照顾患有这种疾病的病人。

Project Summary Inflammatory bowel disease (IBD) is a chronic inflammatory condition of the digestive tract with an uncertain etiology. At present, treatment of IBD is limited to 5-aminosalicylates, corticosteroids, and immunosuppressants, including azathioprine and 6-mercaptopurine. Because specific and curative treatments with acceptable toxicity and side effect profiles are lacking, there remains a demand for the development of effective therapeutic approaches. Of significant importance to the present application are our findings from previous studies, which demonstrated that bacterial products, such as fMLP and MDP, could be transported by the intestinal epithelial oligopeptide transporter, PepT1. Once taken up into the cytosol, these small bacterial peptides initiate an inflammatory response. These bacterial peptides can also interact directly with immune cells. Since immune cells, including macrophages, also express PepT1, they have the capacity to take up small bacterial peptides, which can then interact with the NBS- LRR family of intracellular receptors (e.g., NOD2) that mediate intracellular recognition of microbes and their products. Thus, together with the inflammatory response initiated at the epithelial level, these small bacterial peptides in immune system cells may lead to an inflammatory cascade that results in tissue damage. Our overall hypothesis is that PepT1 plays a critical role in regulating the immune response by serving as a gateway for bacterial products. The initial aim of this proposal is to investigate the induction of PepT1 expression in colonic epithelial cells. Secondly, we will investigate the role of immune cell-expressed PepT1 in intestinal inflammation using chimeric mice. Finally, PepT1 will be used to target the anti-inflammatory tripeptide, KPV, to inflamed colonic epithelial and immune cells. The project will involve a variety of biochemical and molecular approaches at both the in vitro and in vivo level. The proposed study will generate new insights that will be key to the design and development of therapeutic strategies to ameliorate intestinal inflammatory conditions, including IBD. More than one million adults and children in the United States suffer from IBD. New therapeutic strategies based on a better understanding of the pathogenesis of IBD will improve the clinical care of patients with this disorder.