Bone morphogenetic protein-7 and interferon-alpha synergistically suppress hepatitis C virus replicon

Various cytokines contribute to control hepatitis C virus (HCV) viral replication. HCV subgenomic replicon systems have been developed, and cell-cycle-dependent replication has been reported. But the molecules involved in this processes is not totally elucidated. The aim of this study is to investigate the involvement of the bone morphogenetic protein (BMP)-7, a member of TGF-β superfamily, to the in vitro HCV replication. BMP-7 dose-dependently suppressed the replication and protein expression from the HCV replicon in Huh7/Rep-Feo cells and was associated with cell-cycle arrest at the G1 phase. These results were consistent with the effect of TGF-β in a previous study. Combination of BMP-7 and interferon-alpha showed a synergic decrease of HCV replication, and was more effective compared to the treatment with interferon-alpha alone. This synergistic effect was also present in HCV-JFH1 virus cell culture. While BMP-7 alone did not stimulate expression of the interferon-stimulated genes (ISGs), it augmented interferon-induced expression of the ISGs independently of the interferon-induced Jak/STAT pathway. Taken together, BMP-7 may constitute a novel molecule to suppress HCV replication.