A dysregulated hepcidin-iron axis impairs antiviral immunity and induces lethal liver pathology in neonates.

Systemic rotavirus (RV) infection poses a substantial health challenge in neonates, but the underlying pathogenesis remains elusive. In RV-infected neonatal mice and infants with biliary atresia (BA), we discovered that persistent type I interferon (IFN-I) signaling upregulated hepcidin expression in hepatocytes and TREM2+ macrophages. This impaired SLC40A1-mediated iron excretion, leading to lipid peroxidation- and ferroptosis-mediated tissue damage. In mice deficient in Slc40a1 in myeloid cells, iron accumulation promoted RV replication and IFN-I activation in Kupffer cells. Blocking IFN-I-hepcidin signaling and iron chelation reduced RV-induced tissue damage in mice. Folic acid suppressed IFN-I-hepcidin-iron signaling in mice, and in an open-label clinical trial, folic acid supplementation in infants with BA reduced cholangitis and liver transplantation rates. Our data show that hepcidin-iron dysregulation plays a critical role in neonatal RV infection and reveal therapeutic targets for BA and other RV-related neonatal diseases. The clinical trial was registered in the Chinese Clinical Trial Registry ChiCTR2100050992.