Human poliovirus receptor contributes to biliary atresia pathogenesis by exacerbating natural‐killer‐cell‐mediated bile duct injury

Abstract Background and Aims Natural killer (NK) cells play an important role in biliary atresia (BA) pathogenesis; human poliovirus receptor (PVR) is an important NK‐cell modulator. Here, we explored the role of PVR in BA pathogenesis. Methods Poliovirus receptor expression and NK cell‐associated genes were detected in human BA samples and a rotavirus‐induced BA mouse model using quantitative PCR and immunofluorescence staining. Chemically modified small interfering RNA silenced PVR expression in the BA model, and its effects on the population and function of intrahepatic NK cells were investigated using flow cytometry (FCM). The effects of PVR overexpression and knockdown on proliferation, apoptosis and NK‐cell‐mediated lysis of cultured human cholangiocytes were analysed using FCM and cell viability assays. Serum PVR, high‐mobility group box 1 (HMGB1), and interleukin‐1beta (IL‐1beta) levels were measured in a cohort of 50 patients using ELISA. Results Poliovirus receptor expression was upregulated in the biliary epithelium of BA patients and BA model and was positively correlated with the population and activation of intrahepatic NK cells. Silencing of PVR expression impaired the cytotoxicity of NK cells, reduced inflammation and protected mice from rotavirus‐induced BA. Activation of the TLR3‐IRF3 signalling pathway induced PVR expression in cultured cholangiocytes. PVR overexpression promoted proliferation and inhibited the apoptosis of cholangiocytes but exacerbated NK cell‐mediated cholangiocyte lysis. Serum PVR levels were elevated in BA patients and were positively correlated with HMGB1 and IL‐1beta levels. Conclusions Poliovirus receptor contributes to BA pathogenesis by regulating NK cell‐mediated bile duct injury; PVR has the value as a biomarker of BA.