Rhesus rotavirus receptor-binding site affects high mobility group box 1 release, altering the pathogenesis of experimental biliary atresia

Authors: Mohanty, Sujit; DONNELLY, BRYAN - Cincinnati Children'S Research Hospital; TEMPLE, HALEY - Cincinnati Children'S Research Hospital; MOWERY, SARAH - Cincinnati Children'S Research Hospital; POLING, HOLLY - Cincinnati Children'S Research Hospital; MELLER, JAROSLAW - Cincinnati Children'S Research Hospital; MALIK, ASTHA - Cincinnati Children'S Research Hospital; MCNEAL, MONICA - Cincinnati Children'S Research Hospital; TIAO, GREG - Cincinnati Children'S Research Hospital

Submitted to: Hepatology Communications
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/30/2022
Publication Date: 7/22/2022
Citation: Mohanty, S.K., Donnelly, B., Temple, H., Mowery, S., Poling, H.M., Meller, J., Malik, A., Mcneal, M., Tiao, G. 2022. Rhesus rotavirus receptor-binding site affects high mobility group box 1 release, altering the pathogenesis of experimental biliary atresia. Hepatology Communications. 6(10):2702-2714. https://doi.org/10.1002/hep4.2024.
DOI: https://doi.org/10.1002/hep4.2024

Interpretive Summary: Biliary atresia (BA) is a newborn disease causing bile duct blockage that requires a surgery to maintain bile flow from the liver. Even after a successful surgery, most patients develop liver disease requiring a liver transplantation for survival. In the rotavirus infected mouse model of BA, following infection, newborn mice liver shows a pattern similar to that seen in human biliary atresia (BA) patients. The mouse model is caused by a binding of the virus protein to another surface proteins on the cells of bile ducts. In this study we investigated how different changes in gene/proteins resulted in different outcome of BA. We have shown earlier that following virus infection, binding of viral protein to another protein called Hsc70 on bile duct surface resulted in release of a protein called HMGB1 from the bile duct cells. Infection of mice with a virus which do not have this protein, resulted in a lower level of HMGB1 release from bile duct cells and in the serum of infected pups. Virus infection of Hsc70 minus cells (cells which don't have Hsc70) resulted in no HMGB1 release but when these Hsc70 minus cells were substituted with a Hsc70, HMGB1 release was reestablished indicating a important role for Hsc70. Conclusion: The result of this study suggests that binding to Hsc70 contributes to HMGB1 release; therefore Hsc70/HMGB1 can potentially serves as a therapeutic target for BA.

Technical Abstract: Biliary atresia (BA) is a neonatal inflammatory cholangiopathy that requires surgical intervention by Kasai portoenterostomy to restore biliary drainage. Even with successful portoenterostomy, most patients diagnosed with BA progress to end-stage liver disease, necessitating a liver transplantation for survival. In the murine model of BA, rhesus rotavirus (RRV) infection of neonatal mice induces an inflammatory obstructive cholangiopathy that parallels human BA. The model is triggered by RRV viral protein (VP)4 binding to cholangiocyte cell-surface proteins. High mobility group box 1 (HMGB1) protein is a danger-associated molecular pattern that when released extracellularly moderates innate and adaptive immune response. In this study, we investigated how mutations in three RRV VP4-binding sites, RRVVP4-K187R (sialic acid-binding site), RRVVP4-D308A (integrin a2ß1-binding site), and RRVVP4-R446G (heat shock cognate 70 [Hsc70]-binding site), affects infection, HMGB1 release, and the murine model of BA. Newborn pups injected with RRVVP4-K187R and RRVVP4-D308A developed an obstruction within the extrahepatic bile duct similar to wild-type RRV, while those infected with RRVVP4-R446G remained patent. Infection with RRVVP4-R446G induced a lower level of HMGB1 release from cholangiocytes and in the serum of infected pups. RRV infection of HeLa cells lacking Hsc70 resulted in no HMGB1 release, while transfection with wild-type Hsc70 into HeLa Hsc70-deficient cells reestablished HMGB1 release, indicating a mechanistic role for Hsc70 in its release. Conclusion: Binding to Hsc70 contributes to HMGB1 release; therefore, Hsc70 potentially serves as a therapeutic target for BA.