TLR3 Activation of Hepatic Stellate Cell Line Suppresses HBV Replication in HepG2 Cells

There is limited information about the role of hepatic stellate cells (HSCs) in the liver innate immunity against hepatitis B virus (HBV) infection. We thus examined whether hepatic stellate cell line (LX-2) can be immunologically activated and produce antiviral factors that inhibit HBV replication in HepG2 cells. We found that LX-2 cells expressed the functional Toll-like receptor 3 (TLR3), activation of which by PolyI:C resulted in the selective induction of interferon-β (IFN-β) and IFN-λs, the phosphorylation of IFN regulatory factor 3 (IRF3) and IRF7. When HepG2 cells were treated with supernatant (SN) from PolyI:C-activated LX-2 cells, HBV replication was significantly inhibited. IFN-β and IFN-λ appeared to contribute to LX-2 SN-mediated HBV inhibition, as the antibodies to IFN-β and IFN-λ receptors could largely block the LX-2 SN action. Mechanistically, LX-2 SN treatment of the HepG2 cells indubced a number of antiviral IFN-stimulated genes (ISGs: ISG20, ISG54, ISG56, OAS-1, Trim22 and Trim25) and facilitated the phosphorylation of STATs. These observations support further studies on the role of HSCs in the liver innate immunity against HBV infection.