Differential methylation patterns in paternally imprinted gene promoter regions in sperm from hepatitis B virus infected individuals

Background:Hepatitis B virus (HBV) infection poses a substantial threat to human health, impacting not only infected individuals but also potentially exerting adverse effects on the health of their offspring. The underlying mechanisms driving this phenomenon remain elusive. This study aims to shed light on this issue by examining alterations in paternally imprinted genes within sperm. Methods: A cohort of 35 individuals with normal semen analysis, comprising 17 hepatitis B surface antigen (HBsAg)-positive and 18 negative individuals, was recruited. Based on the previous research and the Online Mendelian Inheritance in Man database (OMIM, https://www.omim.org/), targeted promoter methylation sequencing was employed to investigate 28 paternally imprinted genes associated with various diseases. Results: Bioinformatic analyses revealed 42 differentially methylated sites across 29 CpG islands within 19 genes and four differentially methylated CpG islands within four genes. At the gene level, an increase in methylation of DNMT1 and a decrease in methylation of CUL7, PRKAG2, and TP53 were observed. DNA methylation haplotype analysis identified 51 differentially methylated haplotypes within 36 CpG islands across 22 genes. Conclusions: This is the first study to explore the effects of HBV infection on sperm DNA methylation and the potential underlying mechanisms of intergenerational influence of paternal HBV infection. Overall design: A total of 35 subjects from the Reproductive Center of the First Affiliated Hospital of Anhui Medical University (Hefei, China) were enrolled in this study. All participants underwent in vitro fertilization due to female causes of infertility at this center. Of the 35 patients , 17 were positive for hepatitis B surface antigen (HBsAg) and constituted the case group, while the remaining 18 individuals, negative for HBsAg, were recruited as controls.