NSP4 stimulated ion channels and age-dependent diarrhea

描述（由申请人提供）：轮状病毒是导致 危及生命的腹泻在世界各地的婴儿和儿童。以下病毒 感染，腹泻被视为与病理生理变化， 粘膜液和电解质平衡。我的团队专注于定义一个新的 腹泻的病理生理成分。我们已经证明， 一种称为NSP4的非结构蛋白在正常和囊性病变中均诱导腹泻。 纤维化小鼠幼崽伴有钙敏感性氯化物分泌电流 由胃肠粘膜产生。既不腹泻也不分泌阴离子 发生在成年老鼠身上。在亚细胞水平，NSP4引起磷脂酶C 敏感的细胞内钙（Ca2+）i动员和钙敏感的 卤化物流入粘膜隐窝。NSP4诱导的（Ca2+）i动员（我们的测定 对于受体占有率）不是年龄依赖性的。因此，我们假设NSP4 激活幼鼠粘膜中年龄依赖性的钙敏感氯离子通道 引起氯化物分泌和分泌性腹泻。我们建议研究 天然细胞，以识别和表征电生理和 氯离子通道的药理学特性，因此明确 证明了这种传导在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细胞信号传导机制耦合 NSP4介导的（Ca2+）i的变化，这种电导。这些机械研究 可以确定药理学干预的新靶点， 本案无关这些目标将为年龄依赖性 分泌性腹泻，并可能确定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 钙激活氯离子通道在体外培养的大鼠心肌细胞中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 这样做，我们的结果将提供一个很好的可能性， 轮状病毒胃肠炎和其他传染病的新疗法 发生粘膜（Ca2+）i稳态改变的儿童。

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.