Hepatitis C virus production requires apolipoprotein A-I and affects its association with nascent low-density lipoproteins
- Carmine Mancone1,
- Corinna Steindler1,
- Laura Santangelo1,2,
- Giacoma Simonte1,
- Chrysoula Vlassi1,
- Maria Antonella Longo1,
- Gianpiero D'Offizi1,
- Cristina Di Giacomo1,
- Leopoldo Paolo Pucillo1,
- Laura Amicone2,
- Marco Tripodi1,2,
- Tonino Alonzi1
- 1National Institute for Infectious Diseases L Spallanzani IRCCS, Rome, Italy
- 2Istituto Pasteur-Fondazione Cenci Bolognetti, Dipartimento di Biotecnologie Cellulari ed Ematologia, Università Sapienza, Rome, Italy
- Correspondence to Tonino Alonzi, Laboratory of Gene Expression, National Institute for Infectious Diseases L Spallanzani IRCCS, Via Portuense 292, 00149 Rome, Italy; and Marco Tripodi, Dipartimento di Biotecnologie Cellulari ed Ematologia, Università degli Studi di Roma “Sapienza”, Viale Regina Elena 324, 00161 Rome, Italy.
- Revised 25 August 2010
- Accepted 26 August 2010
- Published Online First 12 October 2010
Background/aims The life cycle of hepatitis C virus (HCV) is intimately linked to the lipid metabolism of the host. In particular, HCV exploits the metabolic machinery of the lipoproteins in several steps of its life cycle such as circulation in the bloodstream, cell attachment and entry, assembly and release of viral particles. However, the details of how HCV interacts with and influences the metabolism of the host lipoproteins are not well understood. A study was undertaken to investigate whether HCV directly affects the protein composition of host circulating lipoproteins.
Methods A proteomic analysis of circulating very low-, low- and high-density lipoproteins (VLDL, LDL and HDL), isolated from either in-treatment naïve HCV-infected patients or healthy donors (HD), was performed using two-dimensional gel electrophoresis and tandem mass spectrometry (MALDI-TOF/TOF). The results obtained were further investigated using in vitro models of HCV infection and replication.
Results A decreased level of apolipoprotein A-I (apoA-I) was found in the LDL fractions of HCV-infected patients. This result was confirmed by western blot and ELISA analysis. HCV cellular models (JFH1 HCV cell culture system (HCVcc) and HCV subgenomic replicons) showed that the decreased apoA-I/LDL association originates from hepatic biogenesis rather than lipoprotein catabolism occurring in the circulation, and is not due to a downregulation of the apoA-I protein concentration. The sole non-structural viral proteins were sufficient to impair the apoA-I/LDL association. Functional evidence was obtained for involvement of apoA-I in the viral life cycle such as RNA replication and virion production. The specific siRNA-mediated downregulation of apoA-I led to a reduction in both HCV RNA and viral particle levels in culture.
Conclusions This study shows that HCV induces lipoprotein structural modification and that its replication and production are linked to the host lipoprotein metabolism, suggesting apoA-I as a new possible target for antiviral therapy.
Funding This work was supported by grants from Ministero della Salute (Ricerca Finalizzata Onc. Ord. 35/07, Ricerca Corrente), MIUR Ministero dell'Università e Ricerca Scientifica and Associazione Italiana per la Ricerca sul Cancro (AIRC).
Competing interests None.
Patient consent Obtained.
Ethics approval This study conformed to the ethical guidelines of the 1975 Declaration of Helsinki and was conducted with the approval of the National Institute for Infectious Diseases L Spallanzani IRCCS, Rome Italy.
Provenance and peer review Not commissioned; externally peer reviewed.