Cholangiocyte expression of α2β1-integrin confers susceptibility to rotavirus-induced experimental biliary atresia

Inoculation of BALB/c mice with rhesus rotavirus ( RRV) in the newborn period results in biliary epithelial cell ( cholangiocyte) infection and the murine model of biliary atresia. Rotavirus infection of a cell requires attachment, which is governed in part by cell-surface expression of integrins such as alpha(2)beta(1). We hypothesized that cholangiocytes were susceptible to RRV infection because they express alpha(2)beta(1). RRV attachment and replication was measured in cell lines derived from cholangiocytes and hepatocytes. Flow cytometry was performed on these cell lines to determine whether alpha(2)beta(1) was present. Cholangiocytes were blocked with natural ligands, a monoclonal antibody, or small interfering RNA against the alpha(2)- subunit and were infected with RRV. The extrahepatic biliary tract of newborn mice was screened for the expression of the alpha(2)beta(1)- integrin. Newborn mice were pretreated with a monoclonal antibody against the alpha(2)- subunit and were inoculated with RRV. RRV attached and replicated significantly better in cholangiocytes than in hepatocytes. Cholangiocytes, but not hepatocytes, expressed alpha(2)beta(1) in vitro and in vivo. Blocking assays led to a significant reduction in attachment and yield of virus in RRV- infected cholangiocytes. Pretreatment of newborn pups with an anti-alpha(2) monoclonal antibody reduced the ability of RRV to cause biliary atresia in mice. Cell-surface expression of the alpha(2)beta(1)- integrin plays a role in the mechanism that confers cholangiocyte susceptibility to RRV infection.