Prominent steatosis with hypermetabolism of the cell line permissive for years of infection with hepatitis C virus.
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.
Center for the Study of Chronic Liver Diseases, Keio University School of Medicine, Tokyo, Japan.
Kazuo
K
Sugiyama
Division of Gastroenterology and Hepatology, Department of Internal Medicine, Keio University School of Medicine, Tokyo, Japan.
Hirotoshi
H
Ebinuma
Division of Gastroenterology and Hepatology, Department of Internal Medicine, Keio University School of Medicine, Tokyo, Japan.
Nobuhiro
N
Nakamoto
Graduate School, Keio University School of Medicine, Tokyo, Japan.
Noriko
N
Sakasegawa
Division of Pharmacotherapeutics, Faculty of Pharmacy, Keio University, Tokyo, Japan.
Yuko
Y
Murakami
Division of Gastroenterology and Hepatology, Department of Internal Medicine, Keio University School of Medicine, Tokyo, Japan.
Po-Sung
PS
Chu
Division of Gastroenterology and Hepatology, Department of Internal Medicine, Keio University School of Medicine, Tokyo, Japan.
Shingo
S
Usui
Division of Gastroenterology and Hepatology, Department of Internal Medicine, Keio University School of Medicine, Tokyo, Japan.
Yuka
Y
Ishibashi
Division of Gastroenterology and Hepatology, Department of Internal Medicine, Keio University School of Medicine, Tokyo, Japan.
Yuko
Y
Wakayama
Division of Gastroenterology and Hepatology, Department of Internal Medicine, Keio University School of Medicine, Tokyo, Japan.
Nobuhito
N
Taniki
Division of Gastroenterology and Hepatology, Department of Internal Medicine, Keio University School of Medicine, Tokyo, Japan.
Hiroko
H
Murata
Division of Pharmacotherapeutics, Faculty of Pharmacy, Keio University, Tokyo, Japan.
Yoshimasa
Y
Saito
Department of Biochemistry and Cell Biology, National Institute of Infectious Disease, Tokyo, Japan.
Masayoshi
M
Fukasawa
Department of Biochemistry and Cell Biology, National Institute of Infectious Disease, Tokyo, Japan.
Kyoko
K
Saito
Division of Gastroenterology and Hepatology, Department of Internal Medicine, Keio University School of Medicine, Tokyo, Japan.
Yoshiyuki
Y
Yamagishi
Virology II, National Institute of Infectious Disease, Tokyo, Japan.
Takaji
T
Wakita
Department of Life and Environmental Sciences, Chiba Institute of Technology, Chiba, Japan.
Hiroshi
H
Takaku
Center for Advanced IBD Research and Treatment, Kitasato Institute Hospital, Kitasato University, Tokyo, Japan.
Toshifumi
T
Hibi
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.
Hidetsugu
H
Saito
Division of Gastroenterology and Hepatology, Department of Internal Medicine, Keio University School of Medicine, Tokyo, Japan.
Takanori
T
Kanai
D000596:Amino Acids / Q000378:metabolism; D053898:Biosynthetic Pathways; D002460:Cell Line; D002784:Cholesterol / Q000378:metabolism; D002999:Clone Cells; D003470:Culture Media; D003897:Desmosterol / Q000378:metabolism; D005227:Fatty Acids / Q000378:metabolism; D005234:Fatty Liver / Q000378:metabolism*; D055785:Gene Knockdown Techniques; D016174:Hepacivirus / Q000502:physiology*; D006526:Hepatitis C / Q000378:metabolism* / Q000473:pathology / Q000821:virology*; D006801:Humans; D042541:Intracellular Space / Q000378:metabolism; D066292:Lipid Droplets / Q000378:metabolism; D055432:Metabolomics; D009249:NADP / Q000378:metabolism; D051267:NF-E2-Related Factor 2 / Q000378:metabolism; D009711:Nucleotides / Q000378:metabolism; D014158:Transcription, Genetic; D015533:Transcriptional Activation / Q000235:genetics; D014280:Triglycerides / Q000378:metabolism; D014764:Viral Proteins / Q000378:metabolism
D000596:Amino Acids; D003470:Culture Media; D005227:Fatty Acids; D051267:NF-E2-Related Factor 2; C495635:NFE2L2 protein, human; D009711:Nucleotides; D014280:Triglycerides; D014764:Viral Proteins; D003897:Desmosterol; D009249:NADP; D002784:Cholesterol