Pseudomonas' effects on the gut barrier from surgery

肠道内仅存在人类机会致病菌铜绿假单胞菌 外科危重患者的肠道，与过高的死亡率(-50%)有关？是三倍以上 在培养出这种病原体阴性的生理匹配的患者之上增加。在这项提案中，我们 提供强有力的证据表明，在手术后收缩的宿主的肠道内，介质被释放 直接向铜绿假单胞菌的分子机制发出信号，以表达一种毒力和致死性的表型。我们 假设特定宿主应激衍生的细菌信号化合物(BSCs)，包括阿片类药物 激动剂(吗啡、kappa和Delta受体激动剂)和干扰素-γ(干扰素-γ)被释放到 肠道对手术压力的反应。我们进一步假设这些化合物直接结合到 铜绿假单胞菌表面特异的细菌膜受体，导致群体感应- 依赖毒力决定因素，PA-I凝集素。我们之前已经证明了PA-I的表达 在肠道内的铜绿假单胞菌中，手术应激在这种病原体中产生了致命的表型， 对其强大的细胞毒素导致严重的上皮通透性缺陷。因此，该计划的具体目标 其应用是：1)确定铜绿假单胞菌表达PA-I所需的基因和受体 对阿片类激动剂和干扰素-γ的反应；2)检验阿片类激动剂和干扰素-γ信号转导P. 铜绿假单胞菌通过其作用表达对肠上皮更毒力的表型 PA-I凝集素；以及3)分离、鉴定和纯化其他宿主来源的细菌信号化合物 在应激过程中释放到肠道中，发出铜绿假单胞菌表达PA-I凝集素的信号。一个详细的 对手术应激宿主和经典宿主之间发展的分子对话的理解 像铜绿假单胞菌这样的机会主义者将在这种高度抵抗和致命的疾病中导致新的治疗靶点 病原体及其最近端阻断感染过程的策略。

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.