BACTERIAL TOXINS INTERACTION WITH THE GUT

在项目1中，我们将研究细菌内外毒素与肠道发育的相互作用。腹泻病是全球范围内婴儿和儿童发病率和死亡率的主要原因之一。我们从临床研究中了解到，早产儿肠道不适当的初始细菌定植可能导致严重炎症，导致早产儿特有的肠道疾病，例如-坏死性小肠结肠炎（NEC）和某些致炎性小肠结肠炎更常见，并且在新生儿期表现得更严重。在人肠道模型（细胞系、器官培养、Ussing室和新生儿期）的初步研究中。在人类肠道模型（细胞系、器官培养、Ussing和异种移植）的初步研究中，我们提供了未成熟的人类肠道通过分泌过量的IL-8（一种中性粒细胞的趋化因子）（内毒素）和过量的氯化物分泌（内毒素）以及过量的氯化物分泌（外毒素）对细菌毒素产生不适当反应的数据。基于这些观察结果，我们对这项研究建议的总体假设是，新生儿细菌性炎症性肠病和某些涉及细菌毒素的分泌性腹泻的发病机制主要是由于不成熟（不适当）的肠上皮细胞对细菌毒素刺激的反应。为了检验这一假设，我们将使用两个毒素肠上皮细胞的“串扰”的范例在人类肠道模型，以表征上皮细胞的反应和这种反应的机制，在不成熟的成熟肠相比。因此，我们的具体目标是：（1）通过检查LPS-LBP-CD 14与工具样受体（TLR）的相互作用和受体后信号转导事件，使用IL-8分泌作为效应子应答，通过检查LPS-LBP-CD 14与胎儿肠上皮细胞的相互作用，检查内毒素与胎儿肠上皮细胞的相互作用（主要是导致NfkappaB活化的IL-1信号转导途径）和（2）通过检查毒素结合和经由cAMP、Gsalpha、核糖基化因子的受体后应答，使用Cl-分泌作为效应物应答来研究外毒素-胎儿肠上皮细胞相互作用，PGE 2和5-HT介导的效应子表达和磷酸化以及其他途径。在检查了内毒素和外毒素与发育中的肠道相互作用的每个步骤后，我们将尝试通过使用已知的突变（营养）因子，使用发育调节步骤本身作为效应器反应，调节任何可识别的发育调节。这些研究可能为使用特定营养因子或营养因子组合预防早产儿和新生儿NEC和腹泻提供基础。

In Project 1, a new research project, we will study the interactions of bacterial endo- exotoxin with the developing gut. Diarrheal disease constitutes one of the major causes of morbidity and mortality in infants and children on a global scale. We know from clinical studies that an inappropriate initial bacterial colonization of the premature intestine may result in severe inflammation leading to an intestinal disease unique to the premature, e.g.-necrotizing enterocolitis (NEC) and that certain toxigenic diarrheas occur more commonly and are manifested more severely in the neonatal period. In preliminary studies in human intestinal models (cell lines, organ culture, Ussing chambers, and neonatal period. In preliminary studies in human intestinal models (cell lines, organ culture, Ussing, and xenograph transplants), we provide data that the immature human intestine inappropriately responds to bacterial toxin by secreting excessive IL-8, a chemokine for neutrophils, (endotoxin) and by excessive chloride secretion (endotoxin and by excessive chloride secretion (exotoxin). Based on these observations, our overall hypothesis for this research proposal is that the pathogenesis of neonatal bacterial inflammatory intestinal diseases and certain secretory diarrheas involving bacterial toxins is principally due to an immature (inappropriate) enterocyte response to the bacterial toxin stimulation. In order to test this hypothesis, we will use two toxin-enterocyte "crosstalk" paradigms in human intestinal models to characterize the epithelial response and the mechanisms of this response in the immature compared to the mature intestine. Accordingly, our specific aim are: (1) to examine endotoxin interaction with the fetal enterocyte using IL-8 secretion as the effector response by examining LPS-LBP-CD14 interaction with the fetal enterocyte using IL-8 secretion as the effector response by examining LPS-LBP-CD14 interaction with tool-like receptors (TLRs) and post- receptor signal transduction events (principally the IL-1 signal transduction pathway leading to NfkappaB activation) and (2) to study exotoxin-fetal enterocyte interaction using Cl-secretion as the effector response by examining toxin binding and post-receptor responses via cAMP, Gsalpha, ribosylation factors, effector expression and phosphorylation and other pathways mediated by PGE2 and 5-HT. Having examined each step in the interaction of endo- and exotoxin with the developing intestine we will attempt we will attempt to modulate any identifiable that is developmentally regulated by using known mutational (trophic) factors using the developmentally regulated step itself as the effector response. These studies may provide the basis for using a specific trophic factor or combination of trophic factors in the prevention of NEC and toxigenic diarrhea in premature and neonatal infants.