TY - JOUR
T1 - Demethylase JMJD6 as a New Regulator of Interferon Signaling
T2 - Effects of HCV and Ethanol Metabolism
AU - Ganesan, Murali
AU - Tikhanovich, Irina
AU - Vangimalla, Shiva Shankar
AU - Dagur, Raghubendra Singh
AU - Wang, Weimin
AU - Poluektova, Larisa I.
AU - Sun, Yimin
AU - Mercer, David F.
AU - Tuma, Dean
AU - Weinman, Steven A.
AU - Kharbanda, Kusum K.
AU - Osna, Natalia A.
N1 - Funding Information:
Funding This work was supported by Merit Review BX001673 from the Department of Veterans Affairs, Office of Research and Development (Biomedical Laboratory Research and Development).
Publisher Copyright:
© 2018 The Authors
PY - 2018
Y1 - 2018
N2 - Background & Aims: Alcohol-induced progression of hepatitis C virus (HCV) infection is related to dysfunction of innate immunity in hepatocytes. Endogenously produced interferon (IFN)α induces activation of interferon-stimulated genes (ISGs) via triggering of the Janus kinase–signal transducer and activator of transcription 1 (STAT1) pathway. This activation requires protein methyltransferase 1–regulated arginine methylation of STAT1. Here, we aimed to study whether STAT1 methylation also depended on the levels of demethylase jumonji domain-containing 6 protein (JMJD6) and whether ethanol and HCV affect JMJD6 expression in hepatocytes. Methods: Huh7.5-CYP (RLW) cells and hepatocytes were exposed to acetaldehyde-generating system (AGS) and 50 mmol/L ethanol, respectively. JMJD6 messenger RNA and protein expression were measured by real-time polymerase chain reaction and Western blot. IFNα-activated cells either overexpressing JMJD6 or with knocked-down JMJD6 expression were tested for STAT1 methylation, ISG activation, and HCV RNA. In vivo studies have been performed on C57Bl/6 mice (expressing HCV structural proteins or not) or chimeric mice with humanized livers fed control or ethanol diets. Results: AGS exposure to cells up-regulated JMJD6 expression in RLW cells. These results were corroborated by ethanol treatment of primary hepatocytes. The promethylating agent betaine reversed the effects of AGS/ethanol. Similar results were obtained in vivo, when mice were fed control/ethanol with and without betaine supplementation. Overexpression of JMJD6 suppressed STAT1 methylation, IFNα-induced ISG activation, and increased HCV-RNA levels. In contrast, JMJD6 silencing enhanced STAT1 methylation, ISG stimulation by IFNα and attenuated HCV-RNA expression in Huh7.5 cells. Conclusions: We conclude that arginine methylation of STAT1 is suppressed by JMJD6. Both HCV and acetaldehyde increase JMJD6 levels, thereby impairing STAT1 methylation and innate immunity protection in hepatocytes exposed to the virus and/or alcohol.
AB - Background & Aims: Alcohol-induced progression of hepatitis C virus (HCV) infection is related to dysfunction of innate immunity in hepatocytes. Endogenously produced interferon (IFN)α induces activation of interferon-stimulated genes (ISGs) via triggering of the Janus kinase–signal transducer and activator of transcription 1 (STAT1) pathway. This activation requires protein methyltransferase 1–regulated arginine methylation of STAT1. Here, we aimed to study whether STAT1 methylation also depended on the levels of demethylase jumonji domain-containing 6 protein (JMJD6) and whether ethanol and HCV affect JMJD6 expression in hepatocytes. Methods: Huh7.5-CYP (RLW) cells and hepatocytes were exposed to acetaldehyde-generating system (AGS) and 50 mmol/L ethanol, respectively. JMJD6 messenger RNA and protein expression were measured by real-time polymerase chain reaction and Western blot. IFNα-activated cells either overexpressing JMJD6 or with knocked-down JMJD6 expression were tested for STAT1 methylation, ISG activation, and HCV RNA. In vivo studies have been performed on C57Bl/6 mice (expressing HCV structural proteins or not) or chimeric mice with humanized livers fed control or ethanol diets. Results: AGS exposure to cells up-regulated JMJD6 expression in RLW cells. These results were corroborated by ethanol treatment of primary hepatocytes. The promethylating agent betaine reversed the effects of AGS/ethanol. Similar results were obtained in vivo, when mice were fed control/ethanol with and without betaine supplementation. Overexpression of JMJD6 suppressed STAT1 methylation, IFNα-induced ISG activation, and increased HCV-RNA levels. In contrast, JMJD6 silencing enhanced STAT1 methylation, ISG stimulation by IFNα and attenuated HCV-RNA expression in Huh7.5 cells. Conclusions: We conclude that arginine methylation of STAT1 is suppressed by JMJD6. Both HCV and acetaldehyde increase JMJD6 levels, thereby impairing STAT1 methylation and innate immunity protection in hepatocytes exposed to the virus and/or alcohol.
KW - Alcohol
KW - HCV
KW - JMJD6
KW - STAT1
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U2 - 10.1016/j.jcmgh.2017.10.004
DO - 10.1016/j.jcmgh.2017.10.004
M3 - Article
C2 - 29693039
AN - SCOPUS:85042478712
SN - 2352-345X
VL - 5
SP - 101
EP - 112
JO - Cellular and Molecular Gastroenterology and Hepatology
JF - Cellular and Molecular Gastroenterology and Hepatology
IS - 2
ER -