Genetic basis of virus induced Biliary Atresia

项目摘要/摘要 胆道闭锁是儿童终末期肝病最常见的病因 这是儿童肝移植的一个适应症。因为在中国发现了致病病毒 胆道闭锁的病因是一种围产期病毒感染 引发免疫介导的对胆管上皮的破坏。小鼠胆汁淤积模型的建立 闭锁支持新生小鼠感染恒河猴轮状病毒(RRV)的病毒致病机制 出现门静脉内炎症和肝外胆管梗阻。RRV目标 而对胆管细胞的感染除了直接损伤胆管细胞外，还可自然诱导 杀伤细胞介导的胆管上皮损伤。 我们先前已经证明，序列“SRL”(氨基)中的氨基酸精氨酸(R) RRV VP4蛋白上的酸445-447)是病毒结合和进入胆管上皮所必需的 细胞。我们开发了一种反向遗传学系统来创造RRV的突变体(RRVVP4-R446G)，该突变体 与野生型RRV相比，VP4蛋白发生了单一氨基酸的变化。在体外，突变体 病毒降低了胆管细胞的结合力和感染性。在体内，它产生的症状较少 和新生小鼠的死亡率，导致胆道闭锁的减轻形式。我们将使用这个 突变株与额外的VP4突变株一起确定RRV如何结合、进入、运输 最终激活胆管细胞的先天免疫反应。我们会 也确定了这些VP4突变体感染和激活浆细胞样树突状细胞的能力. 自然杀手细胞的激活。这些免费的方法将产生对病毒的新见解 诱发胆道闭锁。

Project Summary/Abstract Biliary atresia is the most common cause of pediatric end stage liver disease and the number one indication for pediatric liver transplantation. Because pathogenic viruses have been found in the liver of afflicted children, a proposed etiology for biliary atresia is a perinatal viral infection triggering immune mediated destruction of the biliary epithelium. The murine model of biliary atresia supports a viral pathogenesis as newborn mice infected with rhesus rotavirus (RRV) develop inflammation within the portal tract and extrahepatic bile duct obstruction. RRV targets the cholangiocyte for infection and in addition to direct cholangiocyte injury also induces Natural Killer cell mediated injury to the biliary epithelium. We have previously shown that the amino acid, arginine (R) within the sequence “SRL” (amino acids 445-447) on the RRV VP4 protein is required for viral binding and entry into biliary epithelial cells. We developed a reverse genetics system to create a mutant of RRV (RRVVP4-R446G), which had a single amino acid change in VP4 protein compared to wild type RRV. In vitro, the mutant virus had reduced binding and infectivity in cholangiocytes. In vivo, it produced less symptoms and mortality in neonatal mice, resulting in an attenuated form of biliary atresia. We will use this mutant strain along with additional VP4 mutants to determine how RRV binds to, enters, traffics through the cell, and ultimately activates the cholangiocyte's innate immune response. We will also ascertain these VP4 mutants' ability to infect and activate plasmacytoid dendritic cells leading to Natural Killer cell activation. These complimentary approaches will generate new insight in viral induced biliary atresia.