Expression and functionality of Toll- and RIG-like receptors in HepaRG cells

J Hepatol. 2015 Nov;63(5):1077-85. doi: 10.1016/j.jhep.2015.06.022. Epub 2015 Jul 3.

Abstract

Background & aims: HepaRG cells are considered as the best surrogate model to primary human hepatocyte (PHH) culture to investigate host-pathogen interactions. Yet their innate immune functions remain unknown. In this study, we explored the expression and functionality of Toll-like (TLR) and retinoic acid-inducible gene-1 (RIG-I)-like receptors (RLR) in these cells.

Methods: Gene and protein expression levels of TLR-1 to 9 and RLR in HepaRG were mainly compared to PHH, by RT-qPCR, FACS, and Western blotting. Their functionality was assessed, by measuring the induction of toll/rig-like themselves and several target innate gene expressions, as well as the secretion of IL-6, IP-10, and type I interferon (IFN), upon agonist stimulation. Their functionality was also shown by measuring the antiviral activity of some TLR/RLR agonists against hepatitis B virus (HBV) infection.

Results: The basal gene and protein expression profile of TLR/RLR in HepaRG cells was similar to PHH. Most receptors, except for TLR-7 and 9, were expressed as proteins and functionally active as shown by the induction of some innate genes, as well as by the secretion of IL-6 and IP-10, upon agonist stimulation. The highest levels of IL-6 and IP-10 secretion were obtained by TLR-2 and TLR-3 agonist stimulation respectively. The highest preventive anti-HBV activity was obtained following TLR-2, TLR-4 or RIG-I/MDA-5 stimulations, which correlated with their high capacity to produce both cytokines.

Conclusions: Our results indicate that HepaRG cells express a similar pattern of functional TLR/RLR as compared to PHH, thus qualifying HepaRG cells as a surrogate model to study pathogen interactions within a hepatocyte innate system.

Keywords: Antiviral activity; Hepatitis B virus; Hepatocyte; Pathogen recognition receptor; Toll-like receptor.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Blotting, Western
  • Cells, Cultured
  • DEAD Box Protein 58 / biosynthesis
  • DEAD Box Protein 58 / genetics*
  • DNA, Viral / genetics*
  • Enzyme-Linked Immunosorbent Assay
  • Flow Cytometry
  • Gene Expression Regulation*
  • Hepatitis B / genetics*
  • Hepatitis B / metabolism
  • Hepatitis B / virology
  • Hepatitis B virus / genetics*
  • Hepatocytes / metabolism
  • Hepatocytes / pathology*
  • Hepatocytes / virology
  • Humans
  • Real-Time Polymerase Chain Reaction
  • Receptors, Cytoplasmic and Nuclear
  • Toll-Like Receptors / biosynthesis
  • Toll-Like Receptors / genetics*
  • Virus Replication

Substances

  • DNA, Viral
  • Receptors, Cytoplasmic and Nuclear
  • Toll-Like Receptors
  • DDX58 protein, human
  • DEAD Box Protein 58