Identification of amino acids restricting HBV receptor function in porcine NTCP

With 254 million chronically infected patients, hepatitis B virus (HBV) continues to be a severe health threat. While animal models play a crucial role in developing new therapies, the availability of preclinical HBV models is highly restricted, underlining the urgent need for novel in vivo infection models.

The bona fide HBV receptor, sodium-taurocholate cotransporting polypeptide (NTCP), determines the species and cell-type specificity of HBV. Recent studies have indicated that the expression of human NTCP is the only limiting factor for HBV infection in selected species, such as macaques or pigs.

Here, we confirm HBV infection of pig hepatocytes expressing human NTCP and demonstrate that porcine NTCP does not support HBV binding. By gradually humanizing porcine NTCP and site-directed mutagenesis, we identified amino acids 158 and 167 in porcine NTCP to be the crucial residues limiting HBV interaction. In a proof-of-concept experiment, we showed that the expression of porcine NTCP with humanized amino acids 157-167 renders primary porcine hepatocytes fully susceptible to HBV.

These results pave the way for generating transgenic pigs with humanized porcine chimeric NTCP as a novel, fully immunocompetent infection model for developing and validating new curative HBV therapies.

Publication History

Article published online:
20 January 2025