GIARDIAL CROSSTALK WITH THE HUMAN INTESTINAL EPITHELIUM

蓝氏贾第鞭毛虫是世界范围内腹泻疾病的主要原因，但 其发病机制目前知之甚少。滋养体不是 已知入侵、表达任何毒力因子或引发炎症性 回应。因此，了解贾第鞭毛虫的相互作用至关重要。 与寄生虫和宿主的肠道上皮 透视。这个单元的总体目标是阐明分子， 十二指肠滋养体和贾第鞭毛虫之间的细胞和生化串扰 人肠上皮细胞的体外培养和体外培养 异种移植模型。基本的假设是生理刺激 可能调节贾第鞭毛虫的行为，并使 滋养体，以更好地定居和逃避自然宿主防御。 相反，滋养体的附着可能会引起生理上的相关。 对宿主上皮屏障的反应。我们将确定是否 串扰是由于心包附着在活细胞上或由 释放到环境中的因素。目标1是研究滋养体 对培养的人肠道的存活、生长和附着反应 上皮细胞。目标2是测试暴露于 上皮细胞或它们发出的信号可能：A.导致包囊滋养体 从分化恢复到生长；B.改变整个滋养体 发展计划表现为蛋白质、蛋白质的变化 C.诱导贾第鞭毛膜蛋白的表达 毒力因素。目标3是检验依恋将会 诱导两种滋养体细胞骨架和超微结构的变化 和肠道上皮细胞，这可能会给他们提供关键的见解 互动。目的4评价人异种小肠移植模型 一种研究正常肠上皮细胞对 贾第鞭毛虫的殖民。该系统将允许我们定义主机和 感染所需的寄生虫因子。 这些研究将极大地扩展我们对一个重要的 肠道寄生虫，并有可能对 肠道屏障和防御功能。

Giardia lamblia is a major cause of diarrheal disease worldwide, yet little is known of its mechanisms of pathogenesis. Trophozoites are not known to invade, express any virulence factor, or elicit an inflammatory response. Therefore, it is crucial to understand giardial interactions with the intestinal epithelium from both the parasite and the host perspective. The overall goal of this Unit is to elucidate the molecular, cellular, and biochemical cross talk between giardial trophozoites and human intestinal epithelial cells in vitro and in a human intestinal xenograft model. The underlying hypothesis is that physiologic stimuli from host epithelial cells may modulate giardial behavior and enable trophozoites to better colonize and evade natural host defenses. Conversely, attachment of trophozoites may elicit physiologically relevant responses to the host epithelial barrier. We will determine whether the cross talk is due to giardial attachment to live cells or caused by factors released into the environment. Aim 1 is to investigate trophozoite survival., growth, and attachment responses to cultured human intestinal epithelial cells. Aim 2 is to test the hypothesis that exposure to epithelial cells or signals from them may: A. cause encysting trophozoites to revert from differentiation to growth; B. change overall trophozoite development programs as manifested by alterations in protein, protein phosphorylation, and mRNA fingerprints; C. induce expression of giardial virulence factors. Aim 3 is to test the hypothesis that attachment will induce changes in the cytoskeleton and ultrastructure of both trophozoites and intestinal epithelial cells that may give key insights into their interactions. Aim 4 is to evaluate the human intestinal xenograft model as a system to study the response of normal intestinal epithelial cells to giardial colonization. This system will allow us to define both host and parasite factors required for infection. These studies will greatly extend our understanding of an important intestinal parasite and have the potential to yield new insights into intestinal barrier and defense functions.