Intestinal Lactobacillus and Mucosal Immunomodulation

描述（由申请人提供）：本提案的中心目标是了解益生菌的分子机制，以用于炎症性肠病的新治疗和预防策略。为了确定益生菌抗炎功能的分子基础，本建议包括综合遗传学和肽组学方法。我们的实验室已经获得了新的益生菌机制的证据，包括巨噬细胞抑制促炎tnf的产生。已分离出肠道乳酸菌并检测其肿瘤坏死因子- α (TNF-a)抑制活性。总体假设是益生菌肠道乳杆菌菌株分泌抑制巨噬细胞中TNF-a信号并抑制肠道炎症的肽。我们将利用toll样受体激动剂激活巨噬细胞，在体外研究调节益生菌活性（包括肽分泌）的候选乳杆菌基因的功能。将体外缺乏抗炎作用的野生型乳酸菌和敲除型乳酸菌给予il -10缺陷小鼠，以探索益生菌在体内的作用机制。鉴定巨噬细胞中编码抗炎功能的益生菌基因和益生菌反应途径可能为克罗恩病中益生菌作用的潜在人类靶点提供有价值的见解。1. 通过敲除诱变在肠道乳杆菌菌株中指定益生菌抗炎基因。2. 通过乳杆菌分泌组的比较肽组学鉴定抗炎含谷氨酸肽。3. 比较il -10缺陷小鼠肠道粘膜炎症反应与敲除型或野生型等基因益生菌乳酸菌定殖。这些研究将有助于鉴定可用于治疗炎症性肠病（如克罗恩病和溃疡性结肠炎）的有益细菌。我们试图了解有益肠道细菌的作用机制，以便自然或工程地鉴定新的菌株用于人类医学。

DESCRIPTION (provided by applicant): The central goal of this proposal is to understand molecular mechanisms of probiosis for new treatment and prevention strategies in inflammatory bowel disease. This proposal includes comprehensive genetic and peptidomic approaches in order to determine the molecular basis of anti-inflammatory functions by probiotics. Our laboratory has obtained evidence for novel mechanisms of probiosis including inhibition of pro-inflammatory TNFa production by macrophages. Intestinal lactobacilli have been isolated and tested for tumor necrosis factor-alpha (TNF-a)-inhibitory activity. The overall hypothesis is that probiotic intestinal Lactobacillus strains secrete peptides that suppress TNF-a signaling in macrophages and inhibit intestinal inflammation. The functions of candidate Lactobacillus genes that regulate probiotic activities including peptide secretion will be studied in vitro using macrophages activated by Toll-like receptor agonists. Wild type lactobacilli and knockout Lactobacillus strains lacking anti-inflammatory effects in vitro will be administered to IL-10-deficient mice in order to explore mechanisms of probiotic action in vivo. Identification of probiotic genes encoding anti-inflammatory functions and probiotic response pathways in macrophages may provide valuable insights into potential human targets for probiotic action in Crohn's disease. 1. Specify probiotic anti-inflammatory genes in intestinal Lactobacillus strains by knockout mutagenesis. 2. Identify anti-inflammatory glutamate-containing peptides by comparative peptidomics of the Lactobacillus secretome. 3. Compare mucosal inflammatory responses in the intestines of IL-10-deficient mice colonized with knockout or wild type isogenic strains of probiotic Lactobacillus. These studies will facilitate the identification of beneficial bacteria that can be used to treat inflammatory bowel disease such as Crohn's disease and ulcerative colitis. We seek to understand the mechanisms of action of beneficial intestinal bacteria so that new strains can be identified naturally or engineered for human medicine.