Pseudomonas' effects on the gut barrier from surgery

仅仅是人类机会致病菌，铜绿假单胞菌在肠道内的存在 一个危重的外科病人的道，是相关的死亡率过高（-50%）<$a超过3倍 高于生理学匹配的患者，这些患者对该病原体培养呈阴性。在本提案中，我们 提供了强有力的证据，表明在应激宿主的肠道内， 直接向铜绿假单胞菌的分子机制发出信号以表达毒性和致死表型。我们 假设特定宿主应激衍生的细菌信号化合物（BSC），包括阿片样物质， 受体激动剂（吗啡、κ和δ受体激动剂）和干扰素-γ（IFN-γ）被释放到细胞内。 肠道对手术应激的反应。我们进一步假设，这些化合物直接结合到 铜绿假单胞菌上的特异性细菌膜受体，导致群体感应的表达- 依赖的毒力决定因子，PA-1凝集素。我们先前已经证明，PA-1的表达， 在手术应激的肠道内的铜绿假单胞菌中在该病原体中产生致死表型， 诱导其强效细胞毒素的严重上皮通透性缺陷。因此，具体目标 目的：1）确定铜绿假单胞菌表达PA-1所需的基因和受体 2）验证阿片激动剂和IFN-γ信号转导P. 铜绿假单胞菌通过其对肠上皮细胞的作用，表达对肠上皮细胞更具毒性的表型。 PA-I凝集素;和3）分离、鉴定和纯化另外的宿主来源的细菌信号传导化合物 在应激期间释放到肠中，其向铜绿假单胞菌发出信号以表达PA-1凝集素。详细 了解在手术应激宿主和经典的 机会主义者，如铜绿假单胞菌，将在这种高度耐药和致命的疾病中产生新的治疗靶标。 病原体和策略，以阻断在其最近点的传染过程。

The mere presence of the human opportunistic pathogen, Pseudomonas aeruginosa within the intestinal tract of a critically ill surgical patient, is associated an excessive mortality rate (-50%)¿a more than 3-fold increase above physiologically-matchedpatients who culture negative for this pathogen. In this proposal, we provide strong evidence that within the intestinal tract of a surgicallystressed host, mediators are released that directly signal the molecular machinery of P. aeruginosa to express a virulent and lethal phenotype. We hypothesize that specific host stress-derived Bacterial Signaling Compounds (BSCs), includingopioid agonists (morphine, kappa and delta receptor agonists) and Interferon-gamma (IFN-y), are released into the intestinal tract in response to surgical stress. We further hypothesize that these compounds directly bind to specific bacterial membrane receptors on P. aeruginosa that lead to the expression of the quorum sensing- dependent virulence determinant, the PA-I lectin. We have previously demonstrated that expression of PA-I in P. aeruginosa within the intestinal tract of a surgically stressed creates a lethal phenotype in this pathogen, inducing a profound epithelial permeability defect to its potent cytotoxins. Therefore, the Specific Aims of this application are:1) To define the genes and receptors that are required for P. aeruginosa to express PA-I in response to opioid agonists and IFN-y; 2) To test the hypothesis that opioid agonists and IFN-y signal P. aeruginosa to express a more virulent phenotype against the intestinal epithelium through the action of its PA-I lectin; and 3) To isolate, identify, and purify additional host-derived bacterial signaling compounds released into the intestine during stress that signal P. aeruginosa to express the PA-I lectin. A detailed understanding of the moleculardialogue that develops between a surgically stressed host and a classic opportunist like P. aeruginosa will lead to novel therapeutic targets in this highly resistant and lethal pathogen and strategies to interdict in the infectious process at its most proximal point.