title: The Paradoxical Effects of Different Hepatitis C Viral Loads on Host DNA Damage and Repair Abilities.
abstract: Hepatitis C virus (HCV)-induced hepatic stress is associated with increased oxidative DNA damage and has been implicated in hepatic inflammation. However, HCV infection and replication are uneven and vary among individual hepatocytes. To investigate the effect of the viral load on host DNA damage, we used an Enhanced Yellow Fluorescent Protein gene (EYFP)-tagged HCV virus to distinguish between HCV intracellular high viral load (HVL) cells and low viral load (LVL) cells. The cell sorting efficiency was confirmed by the high expression of the HCV polyprotein. We found DNA damage γ-H2AX foci in the HVL population. Comet assays demonstrated that HVL was related to the extent of the DNA strand breaks. Surprisingly, the DNA qPCR arrays and western blotting showed that the damage-related genes GPX2, MRE11, phospho-ATM, and OGG1 were significantly up-regulated in LVL cells but inversely down-regulated or consistently expressed in HVL cells. The colony survival assay to examine the repair abilities of these cells in response to irradiation showed that the LVL cells were more resistant to irradiation and had an increased ability to repair radiation-induced damage. This study found that intracellular viral loads drove cellular DNA damage levels but suppressed damage-related gene expression. However, the increase in damage-related gene expression in the LVL cells may be affected by ROS from the HVL cells. These findings provide new insights into the distinct DNA damage and repair responses resulting from different viral loads in HCV-infected cells.
authors.affiliation: Health Management Center, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung, Taiwan.
authors.forename: Shu-Chi
authors.initials: SC
authors.lastname: Wang
authors.affiliation: Changhua Christian Hospital, Changhua, Taiwan.
authors.forename: Kuan-Ru
authors.initials: KR
authors.lastname: Lai
authors.affiliation: Graduate Institute of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan.|Center for Infectious Disease and Cancer Research, Kaohsiung Medical University, Kaohsiung, Taiwan.
authors.forename: Chia-Yang
authors.initials: CY
authors.lastname: Li
authors.affiliation: Department of Biomedical Engineering and Environmental Sciences, National Tsing-Hua University, Hsinchu, Taiwan.
authors.forename: Chi-Shiun
authors.initials: CS
authors.lastname: Chiang
authors.affiliation: National Institute of Infectious Diseases and Vaccinology, National Health Research Institutes, Miaoli, Taiwan.
authors.forename: Guann-Yi
authors.initials: GY
authors.lastname: Yu
authors.affiliation: Department of Gastroenterology and Hepatology, Tokyo Medical and Dental University, Tokyo, Japan.
authors.forename: Naoya
authors.initials: N
authors.lastname: Sakamoto
authors.affiliation: Hepatobiliary Division, Department of Internal Medicine, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung, Taiwan.
authors.forename: Wen-Yu
authors.initials: WY
authors.lastname: Tu
authors.affiliation: Health Management Center, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung, Taiwan.|Faculty of Medicine College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan.
authors.forename: Meng-Hsuan
authors.initials: MH
authors.lastname: Hsieh
authors.affiliation: Hepatobiliary Division, Department of Internal Medicine, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung, Taiwan.|Graduate Institute of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan.
authors.forename: Jee-Fu
authors.initials: JF
authors.lastname: Huang
authors.affiliation: Center for Infectious Disease and Cancer Research, Kaohsiung Medical University, Kaohsiung, Taiwan.|Hepatobiliary Division, Department of Internal Medicine, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung, Taiwan.|Faculty of Medicine College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan.|Graduate Institute of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan.
authors.forename: Wan-Long
authors.initials: WL
authors.lastname: Chuang
authors.affiliation: Health Management Center, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung, Taiwan.|Center for Infectious Disease and Cancer Research, Kaohsiung Medical University, Kaohsiung, Taiwan.|Hepatobiliary Division, Department of Internal Medicine, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung, Taiwan.|Faculty of Medicine College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan.|Graduate Institute of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan.
authors.forename: Chia-Yen
authors.initials: CY
authors.lastname: Dai
authors.affiliation: Center for Infectious Disease and Cancer Research, Kaohsiung Medical University, Kaohsiung, Taiwan.|Hepatobiliary Division, Department of Internal Medicine, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung, Taiwan.|Faculty of Medicine College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan.|Graduate Institute of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan.|Center for Lipid and Glycomedicine Research, Kaohsiung Medical University, Kaohsiung, Taiwan.|Institute of Biomedical Sciences, National Sun Yat-Sen University, Kaohsiung, Taiwan.
authors.forename: Ming-Lung
authors.identifier: 0000-0001-8145-1900
authors.initials: ML
authors.lastname: Yu
mesh_terms: D015153:Blotting, Western; D045744:Cell Line, Tumor; D004249:DNA Damage; D004260:DNA Repair / Q000235:genetics / Q000528:radiation effects; D005434:Flow Cytometry; D016174:Hepacivirus / Q000502:physiology* / Q000528:radiation effects; D054884:Host-Pathogen Interactions / Q000528:radiation effects; D006801:Humans; D016133:Polymerase Chain Reaction; D011839:Radiation, Ionizing; D019562:Viral Load / Q000502:physiology* / Q000528:radiation effects; D014764:Viral Proteins / Q000378:metabolism
chemical_list: D014764:Viral Proteins