Receptors and Signals in Coxsackievirus Pathogenesis

性状（由申请方提供）：科萨基B病毒（CBV）与两种受体相互作用以启动感染。所有CBV通过附着于柯萨奇病毒和腺病毒受体（CAR）来启动感染;许多CBV分离物还结合第二种受体，人衰变加速因子（CAR）。CBV与其他肠道病毒一样，在人类中通过粪-口途径传播，并通过穿过肠粘膜引发感染;然而，CAR不在排列在肠腔中的极化上皮细胞的顶端表面上表达。在这项资助的第一个资助期内，我们发现，细胞分裂素对极化细胞的感染是必不可少的。它允许病毒附着在细胞表面，但更重要的是，它诱导多种细胞内信号，这些信号是病毒摄入细胞所需的。我们已经发现，额外的病毒诱导的信号通过激活钙依赖性蛋白酶（钙蛋白酶）启动非凋亡性细胞死亡。基于这些观察结果，我们提出了一系列新的实验，重点是病毒相互作用与肠道途径，肠道感染中的作用，钙介导的死亡信号的机制和重要性。1.我们将定义的网站上的病毒表面上，允许附件到ESTA，和ESTA分子上负责与病毒相互作用的网站，使用定点诱变测试模型的病毒ESTA复合物最近来自冷冻EM实验。2.我们将使用在肠上皮细胞上表达人p53的转基因小鼠，确定p53在上皮细胞表面的表达是否对肠内途径的体内感染重要。3.我们将确定导致培养的肠上皮细胞坏死的信号通路，确定钙蛋白酶激活是否有助于感染动物心肌炎和胰腺炎的发病机制，并测试钙蛋白酶抑制剂是否降低疾病的严重程度。 相关性：在美国，肠道病毒是病毒性脑膜炎的主要原因，也是心肌炎的第二大原因。了解病毒如何与其肠道受体相互作用，因为它启动感染，并了解病毒诱导的细胞死亡的机制，可能会提供新的治疗干预的目标。

DESCRIPTION (provided by applicant): Coxsackie B viruses (CBV) interact with two receptors to initiate infection. All CBV initiate infection by attaching to the coxsackievirus and adenovirus receptor (CAR); many CBV isolates also bind to a second receptor, human decay accelerating factor (DAF). CBV, like other enteroviruses, are transmitted by the fecal-oral route in humans, and initiate infection by crossing the intestinal mucosa; however, CAR is not expressed on the apical surface of the polarized epithelial cells that line the intestinal lumen. In the first funding period of this grant, we have found that DAF is essential for infection of polarized cells. DAF permits virus to attach to the cell surface, but more importantly, it induces multiple intracellular signals that are required for virus uptake into the cell. We have found that additional virus-induced signals initiate non-apoptotic cell death by activating calcium-dependent proteases (calpains). Based on these observations, we propose a new series of experiments, focused on virus interaction with DAF, the role of DAF in infection by the enteral route, and the mechanisms and importance of calcium-mediated death signals. 1. We will define the site on the virus surface that permits attachment to DAF, and the site on the DAF molecule responsible for interaction with virus, using site-directed mutagenesis to test a model of the virus-DAF complex recently derived from cryo-em experiments. 2. We will determine whether DAF expression on the epithelial cell surface is important for in vivo infection by the enteral route, using transgenic mice expressing human DAF on intestinal epithelium. 3. We will define the signaling pathway that leads to necrotic cell death in cultured intestinal epithelium, determine whether calpain activation contributes to the pathogenesis of myocarditis and pancreatitis in infected animals, and test whether calpain inhibitors reduce the severity of disease. Relevance: Enteroviruses are the major cause of viral meningitis, and the second major cause of myocarditis in the US. Understanding how virus interacts with its intestinal receptor as it initiates infection, and understanding the mechanisms of virus-induced cell death, may provide new targets for therapeutic intervention.