Ji-Hua Ren1, Jie-Li Hu1,2, Sheng-Tao Cheng1, Hai-Bo Yu1, Vincent Kam Wai Wong3, Betty Yuen Kwan Law3, Yong-Feng Yang4, Ying Huang1, Yi Liu1, Wei-Xian Chen5, Xue-Fei Cai1, Hua Tang1, Yuan Hu1, Wen-Lu Zhang1, Xiang Liu1, Quan-Xin Long1, Li Zhou6, Na-Na Tao1, Hong-Zhong Zhou1, Qiu-Xia Yang1, Fang Ren1, Lin He1, Rui Gong1, Ai-Long Huang1,2, Juan Chen1. 1. The Key Laboratory of Molecular Biology of Infectious Diseases designated by the Chinese Ministry of Education, Institute for Viral Hepatitis, Department of Infectious Diseases, The Second Affiliated Hospital, Chongqing Medical University, Chongqing, China. 2. Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Zhejiang University, Zhejiang, China. 3. State Key Laboratory of Quality Research in Chinese Medicine, Macau University of Science and Technology, Macau, China. 4. Department of Liver Disease, The Second Hospital of Nanjing, Affiliated to Southeast University, Nanjing, China. 5. Department of Clinical Laboratory, The Second Affiliated Hospital of Chongqing Medical University, Chongqing, China. 6. Department of Epidemiology, School of Public Health and Management, Chongqing Medical University, Chongqing, China.
Abstract
Hepatitis B virus (HBV) infection remains a major health problem worldwide. Maintenance of the covalently closed circular DNA (cccDNA), which serves as a template for HBV RNA transcription, is responsible for the failure of eradicating chronic HBV during current antiviral therapy. cccDNA is assembled with cellular histone proteins into chromatin, but little is known about the regulation of HBV chromatin by histone posttranslational modifications. In this study, we identified silent mating type information regulation 2 homolog 3 (SIRT3) as a host factor restricting HBV transcription and replication by screening seven members of the sirtuin family, which is the class III histone deacetylase. Ectopic SIRT3 expression significantly reduced total HBV RNAs, 3.5-kb RNA, as well as replicative intermediate DNA in HBV-infected HepG2-Na+ /taurocholate cotransporting polypeptide cells and primary human hepatocytes. In contrast, gene silencing of SIRT3 promoted HBV transcription and replication. A mechanistic study found that nuclear SIRT3 was recruited to the HBV cccDNA, where it deacetylated histone 3 lysine 9. Importantly, occupancy of SIRT3 on cccDNA could increase the recruitment of histone methyltransferase suppressor of variegation 3-9 homolog 1 to cccDNA and decrease recruitment of SET domain containing 1A, leading to a marked increase of trimethyl-histone H3 (Lys9) and a decrease of trimethyl-histone H3 (Lys4) on cccDNA. Moreover, SIRT3-mediated HBV cccDNA transcriptional repression involved decreased binding of host RNA polymerase II and transcription factor Yin Yang 1 to cccDNA. Finally, hepatitis B viral X protein could relieve SIRT3-mediated cccDNA transcriptional repression by inhibiting both SIRT3 expression and its recruitment to cccDNA. CONCLUSION: SIRT3 is a host factor epigenetically restricting HBV cccDNA transcription by acting cooperatively with histone methyltransferase; these data provide a rationale for the use of SIRT3 activators in the prevention or treatment of HBV infection. (Hepatology 2018).
Hepatitis B virus (HBV) infection remains a major health problem worldwide. Maintenance of the covalently closed circular DNA (cccDNA), which serves as a template for HBV RNA transcription, is responsible for the failure of eradicating chronic HBV during current antiviral therapy. cccDNA is assembled with cellular histone proteins into chromatin, but little is known about the regulation of HBV chromatin by histone posttranslational modifications. In this study, we identified silent mating type information regulation 2 homolog 3 (SIRT3) as a host factor restricting HBV transcription and replication by screening seven members of the sirtuin family, which is the class III histone deacetylase. Ectopic SIRT3 expression significantly reduced total HBV RNAs, 3.5-kb RNA, as well as replicative intermediate DNA in HBV-infected HepG2-Na+ /taurocholate cotransporting polypeptide cells and primary human hepatocytes. In contrast, gene silencing of SIRT3 promoted HBV transcription and replication. A mechanistic study found that nuclear SIRT3 was recruited to the HBVcccDNA, where it deacetylated histone 3 lysine 9. Importantly, occupancy of SIRT3 on cccDNA could increase the recruitment of histone methyltransferase suppressor of variegation 3-9 homolog 1 to cccDNA and decrease recruitment of SET domain containing 1A, leading to a marked increase of trimethyl-histone H3 (Lys9) and a decrease of trimethyl-histone H3 (Lys4) on cccDNA. Moreover, SIRT3-mediated HBVcccDNA transcriptional repression involved decreased binding of host RNA polymerase II and transcription factor Yin Yang 1 to cccDNA. Finally, hepatitis B viral X protein could relieve SIRT3-mediated cccDNA transcriptional repression by inhibiting both SIRT3 expression and its recruitment to cccDNA. CONCLUSION:SIRT3 is a host factor epigenetically restricting HBVcccDNA transcription by acting cooperatively with histone methyltransferase; these data provide a rationale for the use of SIRT3 activators in the prevention or treatment of HBV infection. (Hepatology 2018).
Authors: Tobias Flecken; Marie-Anne Meier; Peter Skewes-Cox; David T Barkan; Markus H Heim; Stefan F Wieland; Meghan M Holdorf Journal: J Virol Date: 2019-04-17 Impact factor: 5.103