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，胃肠道，特别是结肠，持续暴露于大量的益生菌及其产物（例如，TLR-配体）。因此，必须严格调节该器官的先天免疫反应，以避免因持续暴露于管腔微生物群而导致的慢性炎症和器官功能障碍。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，TLR信号在肠道支持宿主和管腔之间的复杂关系。这是其他“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，我们将使用DSS敏感和DSS抗性TLR相关突变体来确定调节TLR诱导的促炎和抗炎通路的机制。结肠的炎症、生物化学、微生物和组织学参数将在静止和炎症条件下测定（即，DSS管理）。在SA-2中，我们将使用DC消融和过继转移方法鉴定SA-1中鉴定的突变体中固有层（LP）和脾（SP）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，我们将进一步探讨TLR激活的MDC对结肠上皮的保护作用。其中包括：1）保护肠上皮细胞（IEC）免于细胞死亡和炎性损伤，2）增加IEC的上皮屏障功能和3）增强受损上皮（IEC）的恢复。将采用通过各种生化测定、生理测量（电阻和细胞旁渗漏）、微生物分析（EPEC感染）和信号事件（STAT 1与STATS）进行的解剖。这些研究将提供对TLR-β-半胱氨酸相互作用触发的保护机制的深入了解，所产生的独特的信号级联反应，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.