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PLoS One. 2014 Apr 9;9(4):e94460. doi: 10.1371/journal.pone.0094460. eCollection 2014.

Prominent steatosis with hypermetabolism of the cell line permissive for years of infection with hepatitis C virus.

Author information

1
Center for the Study of Chronic Liver Diseases, Keio University School of Medicine, Tokyo, Japan.
2
Division of Gastroenterology and Hepatology, Department of Internal Medicine, Keio University School of Medicine, Tokyo, Japan.
3
Graduate School, Keio University School of Medicine, Tokyo, Japan.
4
Division of Pharmacotherapeutics, Faculty of Pharmacy, Keio University, Tokyo, Japan.
5
Department of Biochemistry and Cell Biology, National Institute of Infectious Disease, Tokyo, Japan.
6
Virology II, National Institute of Infectious Disease, Tokyo, Japan.
7
Department of Life and Environmental Sciences, Chiba Institute of Technology, Chiba, Japan.
8
Center for Advanced IBD Research and Treatment, Kitasato Institute Hospital, Kitasato University, Tokyo, Japan.
9
Division of Gastroenterology and Hepatology, Department of Internal Medicine, Keio University School of Medicine, Tokyo, Japan; Division of Pharmacotherapeutics, Faculty of Pharmacy, Keio University, Tokyo, Japan.

Abstract

Most of experiments for HCV infection have been done using lytic infection systems, in which HCV-infected cells inevitably die. Here, to elucidate metabolic alteration in HCV-infected cells in a more stable condition, we established an HCV-persistently-infected cell line, designated as HPI cells. This cell line has displayed prominent steatosis and supported HCV infection for more than 2 years, which is the longest ever reported. It enabled us to analyze metabolism in the HCV-infected cells integrally combining metabolomics and expression arrays. It revealed that rate-limiting enzymes for biosynthesis of cholesterol and fatty acids were up-regulated with actual increase in cholesterol, desmosterol (cholesterol precursor) and pool of fatty acids. Notably, the pentose phosphate pathway was facilitated with marked up-regulation of glucose-6-phosphate dehydrogenase, a rete-limiting enzyme, with actual increase in NADPH. In its downstream, enzymes for purine synthesis were also up-regulated resulting in increase of purine. Contrary to common cancers, the TCA cycle was preferentially facilitated comparing to glycolysis pathway with a marked increase of most of amino acids. Interestingly, some genes controlled by nuclear factor (erythroid-derived 2)-like 2 (Nrf2), a master regulator of antioxidation and metabolism, were constitutively up-regulated in HPI cells. Knockdown of Nrf2 markedly reduced steatosis and HCV infection, indicating that Nrf2 and its target genes play important roles in metabolic alteration and HCV infection. In conclusion, HPI cell is a bona fide HCV-persistently-infected cell line supporting HCV infection for years. This cell line sustained prominent steatosis in a hypermetabolic status producing various metabolites. Therefore, HPI cell is a potent research tool not only for persistent HCV infection but also for liver metabolism, overcoming drawbacks of the lytic infection systems.

PMID:
24718268
PMCID:
PMC3981821
DOI:
10.1371/journal.pone.0094460
[Indexed for MEDLINE]
Free PMC Article
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