Distinct antiviral signaling pathways in primary human hepatocytes and their differential disruption by HCV NS3 protease.
OBJECTIVE
Molecular sensors recognize viral nucleic acids and initiate events that subsequently enable cells to control and clear infection. Hepatitis C Virus (HCV) can interfere with the innate host response and the NS3/4A protease was reported to specifically block antiviral signaling pathways, a finding that had yet to be studied in human primary hepatocytes.


METHODS
Freshly isolated human primary hepatocytes, transduced with a lentiviral vector expressing HCV NS3/4A were stimulated with extracellular and intracellular double-stranded RNA (dsRNA) and the innate immune antiviral genes were quantified by quantitative PCR and microarrays analysis.


RESULTS
We demonstrate that sensing receptors of human hepatocytes in primary cultures are stimulated following recognition of either mode of dsRNA delivery, inducing transcriptional up-regulation (over 100-fold) of multiple immune genes, either selectively or independently of recognition pathways. We also report that the intracellular dsRNA-activated innate response is severely compromised upon ectopic expression of the HCV NS3/4A protease gene in normal human primary hepatocytes, and completely restored by treatment with the NS3/4A protease specific inhibitor BILN2061.


CONCLUSIONS
The present study indicates that NS3/4A has a wider protease-dependent effect on the intracellular Pathogen Recognition Receptor (PRR)-mediated immune response than on its extracellular counterpart, which underlies the major role of cytosolic dsRNA receptors in HCV recognition by primary human hepatocytes.
Jouan
Loubna
L
Laboratoire d'immunologie virale, Centre de Recherche du CHUM (CRCHUM), Hôpital Saint-Luc, 264 René Levesque-Est, PEA 312, Québec, Canada.
Melançon
Pierre
P
Rodrigue-Gervais
Ian-Gaël
IG
Raymond
Valérie-Ann
VA
Selliah
Subajini
S
Boucher
Geneviève
G
Bilodeau
Marc
M
Grandvaux
Nathalie
N
Lamarre
Daniel
D
D002478:Cells, Cultured; D020869:Gene Expression Profiling; D016174:Hepacivirus / Q000276:immunology / Q000378:metabolism; D022781:Hepatocytes / Q000276:immunology / Q000378:metabolism* / Q000821:virology*; D006801:Humans; D007113:Immunity, Innate; D066298:In Vitro Techniques; D020411:Oligonucleotide Array Sequence Analysis; D012313:RNA / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction; D017361:Viral Nonstructural Proteins / Q000378:metabolism*; D012697:Serine Endopeptidases; D043583:Nucleoside-Triphosphatase; D053487:DEAD-box RNA Helicases; D000085242:Viral Proteases
D012313:RNA; D017361:Viral Nonstructural Proteins; C084422:NS3 protein, hepatitis C virus; D012697:Serine Endopeptidases; D043583:Nucleoside-Triphosphatase; D053487:DEAD-box RNA Helicases; D000085242:Viral Proteases