Apolipoprotein(a) inhibits hepatitis C virus entry through interaction with infectious particles.
The development of different cell culture models has greatly contributed to increased understanding of the hepatitis C virus (HCV) life cycle. However, it is still challenging to grow HCV clinical isolates in cell culture. If overcome, this would open new perspectives to study HCV biology, including drug-resistant variants emerging with new antiviral therapies. In this study we hypothesized that this hurdle could be due to the presence of inhibitory factors in patient serum. Combining polyethylene glycol precipitation, iodixanol gradient, and size-exclusion chromatography, we obtained from HCV-seronegative sera a purified fraction enriched in inhibitory factors. Mass spectrometric analysis identified apolipoprotein(a) (apo[a]) as a potential inhibitor of HCV entry. Apo(a) consists of 10 kringle IV domains (KIVs), one kringle V domain, and an inactive protease domain. The 10 KIVs are present in a single copy with the exception of KIV type 2 (KIV2), which is encoded in a variable number of tandemly repeated copies, giving rise to numerous apo(a) size isoforms. In addition, apo(a) covalently links to the apolipoprotein B component of a low-density lipoprotein through a disulfide bridge to form lipoprotein(a). Using a recombinant virus derived from the JFH1 strain, we confirmed that plasma-derived and recombinant lipoprotein(a) as well as purified recombinant apo(a) variants were able to specifically inhibit HCV by interacting with infectious particles. Our results also suggest that small isoforms are less inhibitory than the large ones. Finally, we observed that the lipoprotein moiety of HCV lipoviroparticles was essential for inhibition, whereas functional lysine-binding sites in KIV7, KIV8, and KIV10were not required.



Our results identify apo(a) as an additional component of the lipid metabolism modulating HCV infection. (Hepatology 2017;65:1851-1864).
EA4294, Laboratoire de Virologie, Centre Universitaire de Recherche en Santé, Centre Hospitalier Universitaire et Université de Picardie Jules Verne, Amiens, France.
Catarina
C
Oliveira
EA4294, Laboratoire de Virologie, Centre Universitaire de Recherche en Santé, Centre Hospitalier Universitaire et Université de Picardie Jules Verne, Amiens, France.
Carole
C
Fournier
EA4294, Laboratoire de Virologie, Centre Universitaire de Recherche en Santé, Centre Hospitalier Universitaire et Université de Picardie Jules Verne, Amiens, France.
Véronique
V
Descamps
EA4294, Laboratoire de Virologie, Centre Universitaire de Recherche en Santé, Centre Hospitalier Universitaire et Université de Picardie Jules Verne, Amiens, France.
Virginie
V
Morel
Robarts Research Institute, Schulich School of Medicine & Dentistry, Western University, London, ON, Canada.
Corey A
CA
Scipione
Department of Chemistry & Biochemistry, University of Windsor, Windsor, ON, Canada.
Rocco
R
Romagnuolo
Robarts Research Institute, Schulich School of Medicine & Dentistry, Western University, London, ON, Canada.
Marlys L
ML
Koschinsky
INSERM U1088, Centre Universitaire de Recherche en Santé, Centre Hospitalier Universitaire et Université de Picardie Jules Verne, Amiens, France.
Agnès
A
Boullier
Plateforme ICAP, Centre Universitaire de Recherche en Santé, Université de Picardie Jules Verne, Amiens, France.
Paulo
P
Marcelo
EA3900 BIOPI, Biologie des Plantes et Innovation, UFR des Sciences, Université de Picardie Jules Verne, Amiens, France.
Jean-Marc
JM
Domon
EA4294, Laboratoire de Virologie, Centre Universitaire de Recherche en Santé, Centre Hospitalier Universitaire et Université de Picardie Jules Verne, Amiens, France.
Etienne
E
Brochot
EA4294, Laboratoire de Virologie, Centre Universitaire de Recherche en Santé, Centre Hospitalier Universitaire et Université de Picardie Jules Verne, Amiens, France.|Biobanque de Picardie, Centre Hospitalier Universitaire, Amiens, France.
Gilles
G
Duverlie
EA4294, Laboratoire de Virologie, Centre Universitaire de Recherche en Santé, Centre Hospitalier Universitaire et Université de Picardie Jules Verne, Amiens, France.
Catherine
C
Francois
EA4294, Laboratoire de Virologie, Centre Universitaire de Recherche en Santé, Centre Hospitalier Universitaire et Université de Picardie Jules Verne, Amiens, France.
Sandrine
S
Castelain
EA4294, Laboratoire de Virologie, Centre Universitaire de Recherche en Santé, Centre Hospitalier Universitaire et Université de Picardie Jules Verne, Amiens, France.
Francois
0000-0001-6884-2456
F
Helle
D015153:Blotting, Western; D002470:Cell Survival / Q000187:drug effects; D002478:Cells, Cultured; D002853:Chromatography, Liquid / Q000379:methods; D016174:Hepacivirus / Q000187:drug effects / Q000378:metabolism*; D006526:Hepatitis C / Q000097:blood / Q000628:therapy*; D022781:Hepatocytes / Q000187:drug effects / Q000378:metabolism; D006801:Humans; D047468:Immunoprecipitation; D017270:Lipoprotein(a) / Q000494:pharmacology*; D008239:Lysine / Q000378:metabolism; D011485:Protein Binding; D012680:Sensitivity and Specificity; D013329:Structure-Activity Relationship
D017270:Lipoprotein(a); D008239:Lysine