The Molecular Determinants of Virus Induced Biliary Atresia

描述(申请人提供)：胆道闭锁是儿童终末期肝病最常见的原因，也是儿童肝移植的头号适应症。由于在患病儿童的肝脏中发现了致病病毒，故提出的胆道闭锁的病因是围产期病毒感染，引发免疫介导的胆管上皮破坏。胆道闭锁的小鼠模型支持一种病毒致病机制，即感染恒河猴轮状病毒(RRV)的新生小鼠发展为门静脉内炎症和肝外胆管梗阻。RRV以胆管细胞为感染靶点，除直接损伤胆管细胞外，还可诱导T细胞介导的胆管上皮损伤。轮状病毒是由11个基因片段组成的dsRNA病毒。我们假设，特定的轮状病毒基因控制着感染胆管细胞和诱导免疫介导的损伤的能力。为了验证这一假设，我们从亲本RRV和TUCH菌株中产生了一套完整的单基因重组体。这些重组子为我们提供了一套独特的工具来确定特定的轮状病毒基因如何参与发病机制。在初步研究中，我们发现RRV片段3、4、6、8、9和11是感兴趣的基因。考虑到对基因片段4的观察结果的健壮性，我们将重点放在这个基因上。我们将使用RRV-胆管细胞感染和T细胞激活的体外模型来确定基因片段4参与疾病发病的机制。我们还将使用反向遗传学产生突变基因片段4的传染性病毒，以确定在更复杂的环境中的完整宿主的基础。这些互补的方法将在病毒诱导的胆道闭锁中产生新的见解。

DESCRIPTION (provided by applicant): 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 extra- hepatic bile duct obstruction. RRV targets the cholangiocyte for infection and in addition to direct cholangiocyte injury also induces T-cell mediated injury to the biliary epithelium. Rotavirus is a dsRNA virus comprised of 11 gene segments. We hypothesized that specific rotavirus genes govern the ability to infect the cholangiocyte and induce immune mediated injury. To test this hypothesis, we generated a complete set of single gene reassortants derived from the parental strains RRV and TUCH. These reassortants give us a unique set of tools to determine how specific rotavirus genes contribute to the pathogenesis. In preliminary studies, we found that RRV segments 3, 4, 6, 8, 9 and 11 are genes of interest. Given the robust nature of the observations made with gene segment 4, we focused on this gene. We will use in vitro models of RRV - cholangiocyte infection and T-cell activation to determine the mechanisms by which gene segment 4 contributes to disease pathogenesis. We will also use reverse genetics to generate mutate gene segment 4 infectious virus to determine the basis in the more complex environment of the intact host. These complimentary approaches will generate new insight in viral induced biliary atresia.