NSP4 stimulated ion channels and age-dependent diarrhea

描述(申请人提供)：轮状病毒是引起 全世界婴儿和儿童中危及生命的腹泻。关注病毒 感染，腹泻被认为与病理生理变化有关 粘膜液体和电解质平衡。我的团队一直专注于定义一个新的 腹泻的病理生理成分。我们已经证明了一种轮状病毒 一种名为NSP4的非结构蛋白导致正常和囊性腹泻 伴有钙敏感氯离子分泌电流的纤维化小鼠 由胃肠粘膜产生。既不腹泻也不阴离子分泌 发生在成年小鼠身上。在亚细胞水平上，nsp4导致磷脂酶C 敏感的细胞内钙(钙)i动员和钙敏感 卤化物流入粘膜隐窝。NSP4诱导的(Ca~(2+))i动员 受体占有率)与年龄无关。因此，我们假设nsp4 幼犬粘膜钙敏感氯离子通道的激活及其年龄依赖性 引起氯化物分泌，以及分泌性腹泻。我们建议在以下方面进行研究 自然细胞来识别和表征电生理和 氯通道的药理特性，因此毫不含糊 证实这种电导在NSP4介导的年龄依赖性细胞中的作用 卤化物流入。我们打算确定耦合的细胞信号机制 NSP4介导(Ca~(2+))i对此电导的影响。这些机械论研究 可能确定药物干预的新靶点，具有明确的临床意义 关联性。这些目标将为依赖年龄的 分泌性腹泻，并可能识别轮状病毒诱导的分子靶点 跨上皮阴离子分泌。他们还将翻译为 培养细胞钙激活氯通道表达的生物物理学研究 上皮细胞系进入临床医学和疾病领域。在……里面 这样做，我们的结果将提供一个极好的可能性发展 轮状病毒性胃肠炎和其他传染病的新疗法 发生粘膜(钙)i动态平衡改变的儿童。

DESCRIPTION (provided by applicant): Rotaviruses are a major cause of life-threatening diarrhea in infants and children worldwide. Following viral infection, diarrhea is seen associated with pathophysiological changes in mucosal fluid and electrolyte balance. My group has focused on defining a new pathophysiological component to diarrhea. We have shown that a rotaviral non-structural protein called NSP4 induces diarrhea in both normal and cystic fibrosis mouse pups accompanied by calcium-sensitive chloride secretory current generation by gastrointestinal mucosa. Neither diarrhea nor anion secretion occur in adult mice. At the sub-cellular level, NSP4 causes phospholipase C sensitive intracellular calcium (Ca2+)i mobilization and calcium-sensitive halide influx into mucosal crypts. NSP4-induced (Ca2+)i mobilization (our assay for receptor occupancy) is not age-dependent. Thus, we hypothesize that NSP4 activates and age-dependent calcium-sensitive chloride channel in pup mucosa causing chloride secretion, and secretory diarrhea. We propose studies in native cells to identify and characterize the electrophysiological and pharmacological properties of the chloride channel, and thus unequivocally demonstrate a role for this conductance in NSP4 mediated age-dependent cellular halide influx. We intend to identify the cellular signaling mechanisms coupling NSP4 mediated changes in (Ca2+)i to this conductance. These mechanistic studies may identify novel targets for pharmacological intervention with clear clinical relevance. These goals will provide the cellular basis for the age-dependent secretory diarrhea and may identify a molecular target for rotaviral-induced transepithelial anion secretion. They will also translate facts established for the biophysics of calcium-activated chloride channel expression in cultured epithelial cell-lines into the fields of clinical medicine and disease. In doing so, our results will provide an excellent possibility for development of new therapies for rotaviral gastroenteritis, and for other infectious diseases in children where altered mucosal (Ca2+)i homeostasis occurs.