Therapeutic inhibition of HBsAg and HBV cccDNA through a novel phased combination treatment: glycine and interferon-α

Background The elimination of HBV covalently closed circular DNA (cccDNA) remains a critical hurdle for chronic hepatitis B (CHB) management. Objective In this investigation, we examined the efficacy of glycine administration and its potential enhancement in interferon-α (IFN-α) antiviral efficacy to stimulate hepatocyte proliferation to mitigate cccDNA levels. Design The study cohort comprised 89 healthy individuals and 496 HBV-infected patients, with subgroups of 30 and 42 participants receiving randomised nucleos(t)ide analogue (NA) and PegIFN-α treatments, respectively. Glycine concentrations were quantified via liquid chromatography‒tandem mass spectrometry, and its diagnostic potential was assessed via receiver operating characteristic curve analysis. The therapeutic impact of glycine was evaluated in various HBV-infected cell lines and murine models via various methodologies including transcriptomic sequencing, metabolomics sequencing, flow cytometry, immunofluorescence and in situ hybridisation. Results Elevated serum glycine levels with a robust positive correlation with serum alanine aminotransferase levels (R=0.7650) were observed in HBV-infected patients relative to healthy controls. The area under the curve for differentiating patients with HBeAg-expressing CHB from healthy controls was 0.9701. Glycine supplementation diminished HBV cccDNA levels by approximately 50% by promoting hepatocyte proliferation. Glycine is metabolised into a one-carbon unit, activating mTORC1 signalling via glycine transporter-1. Furthermore, glycine ameliorates hepatic inflammation by inhibiting the nuclear factor-kappa B signalling pathway through glycine receptors. Combination therapy with IFN-α effectively suppressed HBV replication, achieving a 60% reduction in HBsAg levels and sustained viral suppression in mice. Conclusion Glycine has the potential to reduce HBV cccDNA levels by stimulating hepatocyte proliferation. The phased administration of glycine and IFN-α significantly enhances its therapeutic efficacy. These findings suggest a novel and promising strategy for the treatment of CHB.