RESUMEN
BACKGROUND AND AIM: The HBV covalently closed circular DNA (cccDNA) is organized into a minichromosome in the nuclei of infected hepatocytes through interactions with histone and nonhistone proteins. Retinoid X receptor α (RXRα), a liver-enriched nuclear receptor, participates in regulation of HBV replication and transcription through modulation of HBV enhancer 1 and core promoter activity. MATERIAL AND METHODS: This study investigated RXRα involvement in HBV cccDNA epigenetic modifications. Quantitative cccDNA chromatin immunoprecipitation (ChIP) was applied to study the recruitment of RXRα, histones, and chromatin-modifying enzymes to HBV minichromosome in HepG2 cells after transfection of the linear HBV genome. RESULTS: RXRα Was found to directly bind to HBV cccDNA; recruitment of RXRα to HBV mini-chromosome paralleled HBV replication, histone recruitment, and histone acetylation in HBVcccDNA. Moreover, RXRα overexpression or knock-down significantly increased or impaired the recruitment of the p300 acetyltransferase to cccDNAminichromosome. CONCLUSIONS: Our results confirmed the regulation of RXRα on HBV replication in vitro and demonstrated the modulation of RXRα on HBV cccDNA epigenetics. These findings provide a profound theoretical and experimental basis for late-model antiviral treatment acting on the HBV cccDNA and minichromosome.
Asunto(s)
ADN Circular/genética , ADN Viral/genética , Virus de la Hepatitis B/genética , Hepatocitos/virología , Receptor alfa X Retinoide/metabolismo , Replicación Viral , Acetilación , Ensamble y Desensamble de Cromatina , ADN Circular/biosíntesis , ADN Viral/biosíntesis , Epigénesis Genética , Regulación Viral de la Expresión Génica , Células Hep G2 , Virus de la Hepatitis B/crecimiento & desarrollo , Virus de la Hepatitis B/metabolismo , Hepatocitos/metabolismo , Histonas/metabolismo , Interacciones Huésped-Patógeno , Humanos , Unión Proteica , Receptor alfa X Retinoide/genética , Factores de Tiempo , Transcripción Genética , Factores de Transcripción p300-CBP/metabolismoRESUMEN
UNLABELLED: Background and aim. Leukocyte antigen DQ (HLA-DQ) and interferon-λ4 (IFNL4) gene polymorphisms were associated with susceptibility to chronic hepatitis B and C virus infection. This study further confirmed that variants of these genes were associated with susceptibility and spontaneous clearance of HBV infection in a Chinese population. MATERIAL AND METHODS: A total of 1,069 subjects were recruited and divided into three groups i.e. 397 with CLD (HBV-related chronic liver disease), 434 with SC (spontaneous clearance), and 238 HC (healthy controls). HLA-DQrs9275319 and IFNL4rs368234815, rs12971396, rs12979860, and rs8099917SNPs were genotyped using the Sequenom MassARRAY MALDI-TOF system. RESULTS: HLA-DQ rs9275319 showed a significant association with HBV infection (allele model, OR, 0.514; 95% CI, 0.359-0.738, adjusted p = 0.0003) and with natural clearance (allele model, OR, 1.659; 95% CI, 1.197-2.300, adjusted. However, there was no association between IFNL4 polymorphism and HBV susceptibility or natural clearance (all p > 0.05). The multifactor dimensionality reduction (MDR) test with permutation correction showed that a three-way interaction between IFNL4 and HLA-DQ SNPs was identified for HBV susceptibility (permutation p = 0.009 for the best factor model) and clearance (permutation p = 0.014 for the best factor model). CONCLUSIONS: The data from the current study provided additional evidence for an SNP-SNP interaction between HLA-DQ and IFNL4 in regulation to HBV infection and natural clearance.