The diverse contribution of TLR pathways to intestinal homeostasis

描述（由申请人提供）：与我们的内部环境相反，G-l通道，特别是结肠，持续暴露于大量的共生体及其产物（例如tlr -配体）。因此，这个器官的先天免疫反应必须严格调节，以避免慢性炎症和器官功能障碍，从持续暴露于肠道微生物群。最近的数据强调了TLR在结肠中的生理任务。我们最近发现了TLR信号在结肠粘膜中的独特调节功能。我们假设肠道中的TLR信号支持宿主和管腔之间的复杂关系。其他“无菌”器官中不存在的微生物群。为了确定独特的结肠特异性tlr启动的分子事件，我们提出了三个SA。在SA-1中，我们将利用dss敏感和dss耐药的tlr相关突变体，确定tlr在结肠中诱导的促炎和抗炎途径的调节机制。在静止和炎症条件下（即DSS给药），将测定结肠的炎症、生化、微生物和组织学参数。在SA-2中，我们将使用DC消融和过继性转移方法确定SA-1突变体中固有层（LP）和脾髓样树突状细胞（MDC）亚群的促炎和抗炎作用。tlr激活的SP-和LP-MDC产生的效应分子将通过功能基因组方法进一步分析。在SA-3中，我们将进一步探索tlr激活的MDC对结肠上皮的保护作用。这些包括：1)保护肠上皮细胞（lEC）免受细胞死亡和炎症损伤；2)增加肠上皮屏障功能；3)促进损伤上皮（IEC）的修复。将采用各种生化分析、生理测量（电阻和细胞旁泄漏）、微生物分析（EPEC感染）和信号事件（STAT1 vs. STATS）进行解剖。这些研究将深入了解tlr -共生体相互作用触发的保护机制，由此产生的独特信号级联，以及支持结肠稳态的效应分子。

DESCRIPTION (provided by applicant): In contrast to our internal environment, the G-l tract, especially the colon, is continuously exposed to a vast number of commensals and their products (e.g., TLR-ligands). The innate immune response of this organ must therefore be tightly regulated to avoid chronic inflammation and organ dysfunction from the constant exposure to luminal microbiota. Recent data has underlined the physiological tasks of TLR in the colon. We recently identified unique regulatory functions of TLR signaling in colonic the colonic mucosa. We hypothesize that TLR signaling in the gut supports a complex relationship between the host and luminal. microbiota that does not exist in other "sterile" organs. To identify the unique colon-specific TLR-initiated molecular events, we propose three SA. In SA-1 we will identify the mechanisms that regulate TLR-induced pro- and anti-inflammatory pathways in the colon using DSS-sensitive and DSS-resistant TLR-related mutants. Inflammatory, biochemical, microbiological and histological parameters of the colon will be determined under quiescent and inflammatory conditions (i.e., DSS administration). In SA-2 we will identify the pro- and anti-inflammatory effects of lamina propria (LP) and splenic (SP) myeloid dendritic cell (MDC) subsets in the mutants identified in SA-1 using DC ablation and adoptive transfer approaches. The effector molecules produced by TLR-activated SP- and LP-MDC will be further analyzed by a functional genomic approach. In SA-3 we will further explore the protective effects mediated by TLR-activated MDC on colonic epithelium. These include: 1) protection of intestinal epithelial cells (lEC) from cell-death and inflammatory insult, 2) increase of epithelial barrier functions of IEC and 3) enhancing the restitution of injured epithelium (IEC). Dissection via diverse biochemical assays, physiological measurements (electrical resistance and paracellular leak), microbiological analysis (EPEC infection) and signaling events (STAT1 vs. STATS) will be employed. These studies will provide insight into protective mechanisms triggered by TLR-commensals interactions, the resulting unique signaling cascade, and the effector molecules that support colonic homeostasis.