Pathogenic Mechanisms of Virus Induced Biliary Atresia

描述（由申请人提供）： 胆道闭锁是新生儿胆汁淤积的最常见原因，如果不治疗，会导致终末期肝病（ESLD）和死亡。即使采用目前的治疗策略，大多数儿童也会发展为进行性肝病，需要进行肝移植进行挽救。胆道闭锁是小儿肝移植的头号适应症。尽管其重要性，胆道闭锁的发病机制是未知的。一个可能的原因是环境因素如易感宿主中的病毒感染。我们建立了一种实验性胆道闭锁小鼠模型，发现一种特定的轮状病毒-恒河猴轮状病毒（RRV）可在易感鼠宿主- BALB/c小鼠中诱导小鼠胆道损伤，并进展为ESLD和死亡。炎症性胆管病起始于胆管上皮细胞水平，反映了婴儿中发现的疾病过程。该模型将用于定义调节病毒与胆道系统之间相互作用的分子机制，以验证过度假设，即胆道闭锁是由病毒对胆道上皮细胞（胆管细胞）的异常识别和感染引起的。这一假设将通过以下具体目的来解决：1）确定诱导小鼠胆道闭锁所需的特异性RRV基因。2)确定胆管细胞易受RRV感染的机制。3)确定RRV感染的胆管细胞触发宿主炎症反应的机制。轮状病毒基因重配特性将用于鉴定引起胆道闭锁小鼠模型的RRV基因。RRV能够感染胆管细胞系的新型体外模型将用于鉴定RRV感染胆管细胞的机制。流式细胞术用于检测已知赋予轮状病毒感染易感性的整合素α 2 β 1的存在。将使用天然配体和针对该蛋白的单克隆抗体进行阻断研究，以确定其作用。在体外，RRV感染的胆管细胞产生趋化因子。这可能是引发宿主炎症反应的触发机制。我们将确定在体内是否发生类似的过程。我们还将确定NF-κ B细胞内途径是否是RRV感染诱导趋化因子产生的机制。

DESCRIPTION (provided by applicant): Biliary atresia is the most common cause of neonatal cholestasis and if untreated results in end-stage liver disease (ESLD) and death. Even with current treatment strategies most children develop progressive liver disease and require liver transplantation for salvage. Biliary atresia is the number one indication for pediatric liver transplantation. Despite its importance, the pathogenesis of biliary atresia is unknown. One possible cause is an infection by an environmental agents such as viruses in a susceptible host. We established an experimental mouse model of biliary atresia and found that biliary injury in mice could be induced by a specific rotavirus species - rhesus rotavirus (RRV) in a susceptible murine host - BALB/c mice that progresses to ESLD and death. The inflammatory cholangiopathy is initiated at the biliary epithelial cell level and mirrors the disease process that is found in infants. This model will be used to define the molecular mechanisms regulating the interaction between a virus and the biliary system testing the over-arching hypothesis that the biliary atresia results from the abnormal recognition and infection of biliary epithelial cells (cholangiocytes) by a virus. This hypothesis will be addressed by the following specific aims: 1) Determine the specific RRV gene(s) necessary for the induction of biliary atresia in mice. 2) Determine the mechanism by which the cholangicoyte is susceptible to RRV infection. 3) Determine the mechanism by which RRV infected cholangiocytes triggers a host inflammatory response. The rotavirus property of gene reassortment will be used to identify the RRV gene(s) that cause the murine model of biliary atresia. A novel in vitro model in which RRV is able to infect a cholangiocyte cell line will be used to identify the mechanism by which RRV infects the cholangicoyte. Flow cytometry was used to detect the presence of the integrin apha2beta1 known to confer vulnerabiity to rotavirus infection. Blocking studies using natural ligands and monoclonal antibodies against this protein will be performed to determine its role. In vitro, cholangiocytes infected by RRV produce chemokines. This may be the triggering mechanism by which the host inflammatory response is initiated. We will determine if a similar process occurs in vivo. We will also determine if the NF-kappaB intracellular pathway is the mechansim by which RRV infection induces chemokine production.