The Role of PAF and TLR in NEC

PAF 和 TLR 在 NEC 中的作用

基本信息

批准号：
7647906
负责人：
MICHAEL S CAPLAN
金额：
$ 27.8万
依托单位：
NORTHSHORE UNIVERSITY HEALTHSYSTEM
依托单位国家：
美国
项目类别：
财政年份：
2000
资助国家：
美国
起止时间：
2000-08-01 至 2011-06-30
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/7647906
关键词：
Address Affect Animals Asphyxia Bacteria Binding C3H/HeJ Mouse C3HeB/FeJ Mouse C57BL/6 Mouse Caspase Cell Culture Techniques Cell Wall Cells Complex Control Animal DNA Fragmentation Data Development Developmental Biology Disease Dominant-Negative Mutation Electrolytes Enterocytes Environment Enzymes Epithelial Epithelial Cells Etiology Event Frozen Sections Functional disorder Funding Gene Expression Genetic Determinism Gram-Negative Bacteria Growth Host Defense Human Hypoxia In Vitro Incidence Inflammation Inflammation Mediators Inflammatory Inflammatory Response Injury Intestines Ischemic Bowel Disease Knock-out Knockout Mice Laboratories Lipopolysaccharides Measures Mediator of activation protein Messenger RNA Modeling Mothers Mus NF-kappa B Necrosis Necrotizing Enterocolitis Neonatal Newborn Animals Operative Surgical Procedures Pathogenesis Pathology Pathway interactions Patients Physiological Platelet Activating Factor Play Premature Infant Principal Investigator Process Protein Biosynthesis Proteins Rattus Reaction Receptor Activation Receptor Gene Receptor Signaling Regulation Reporter Reporter Genes Research Rodent Role STAT3 gene Series Signal Pathway Signal Transduction Specimen Stress Supplementation TLR4 gene Testing Time Toll-like receptors Transgenic Mice United States National Institutes of Health Up-Regulation Work base cell type design feeding in vivo intestinal epithelium laser capture microdissection mouse model mutant neonate novel platelet activating factor receptor prevent programs promoter receptor receptor expression response toll-like receptor 4

项目摘要

DESCRIPTION (provided by applicant): Necrotizing enterocolitis (NEC) is an abrupt and devastating inflammatory necrosis of the bowel affecting 10% of premature infants born weighing less than 1500 grams. Although the etiology of this complex disorder is poorly understood, the evidence suggests that intestinal ischemia, formula feeding, and bacterial challenge activates platelet activating factor (PAF) and other inflammatory mediators leading to intestinal injury. Results from our previous NIH funded project have shown that PAF receptor activation by PAF leads to a series of physiological and/or pathological changes in the intestinal epithelium, including the stimulation of transepithelial electrolyte transport, cytoplasmic acidification, caspase activation and DNA fragmentation. In addition, endogenous bacteria stimulate the inflammatory cascade and are a prerequisite for neonatal NEC. Specific bacterial cell wall products stimulate toll receptors (TLR's) on multiple cell types that result in significant downstream events. In a healthy intestinal environment, the mucosal barrier is poorly responsive to bacterial cell wall products, partly because of low or absent TLR expression. Nonetheless, in the neonate during early development and bacterial colonization, intestinal expression of TLR and regulation of this process is incompletely understood. We hypothesize that during the developmental acquisition of neonatal bacterial colonization with the addition of asphyxia stress, there is abnormal intestinal gene expression of TLR-4, and that PAF contributes to this abnormal upregulation. Following TLR activation, downstream signaling initiates a series of events that culminate in the final common pathway of intestinal necrosis and NEC. Utilizing a novel neonatal mouse model of NEC that will allow testing of genetically-altered animals and cell culture studies that will provide additional mechanistic detail, the research plan is designed to 1) characterize the developmental regulation of intestinal TLR expression and study the importance of TLR in human NEC and the neonatal mouse model, 2) delineate the signaling mechanisms responsible for PAF-induced TLR expression in intestinal epithelial cells from humans and rodents, and 3) investigate the role of PAF on intestinal TLR gene expression and protein synthesis in vivo. The proposed studies will elucidate the interactions between PAF and TLR signaling, and clarify whether these pathways play an underlying role in the initiation of neonatal NEC.

描述（由申请人提供）：坏死性小肠结肠炎（NEC）是肠的突然而毁灭性的炎症坏死，影响10％的早产婴儿体重小于1500克。尽管这种复杂疾病的病因知之甚少，但证据表明，肠缺血，配方奶粉和细菌挑战激活了血小板激活因子（PAF）和其他炎症介质导致肠道损伤。我们以前的NIH资助项目的结果表明，PAF受到PAF受体的激活导致肠上皮的一系列生理和/或病理学变化，包括刺激跨皮物电解质转运，细胞质酸化，caspase酸化，caspase激活和DNA碎片。另外，内源性细菌刺激炎症性级联反应，是新生儿NEC的先决条件。特定的细菌细胞壁产物在多种细胞类型上刺激收费受体（TLR），从而导致重大下游事件。在健康的肠道环境中，粘膜屏障对细菌细胞壁产物的反应不佳，部分原因是TLR表达低或不存在。尽管如此，在早期发育和细菌定植期间的新生儿中，TLR的肠道表达和该过程的调节尚不完全理解。我们假设，在加入新生儿细菌定殖的发展中，加入了窒息应激，TLR-4的肠道基因表达异常，并且PAF有助于这种异常上调。 TLR激活后，下游信号传导启动了一系列事件，这些事件在肠道坏死和NEC的最终公共途径中达到了最终。利用NEC的新型新生小鼠模型，该模型将允许测试遗传变化的动物和细胞培养研究，以提供其他机械细节，研究计划设计为1）表征1）特征是在人NEC和NEEC中的TLR的重要性，并研究人NEC和Neonatal小鼠模型的重要性，并构成了Neonatal小鼠模型，2）在启用paftr paftr，2）人类和啮齿动物，以及3）研究PAF在体内肠道TLR基因表达和蛋白质合成的作用。拟议的研究将阐明PAF和TLR信号之间的相互作用，并阐明这些途径在新生儿NEC的启动中是否起着潜在的作用。