Aberrations in sperm dna methylation patterns of males suffer from infertility problems

Abstract

To identify the aberrations in sperm DNA methylation patterns of males who have been unable to have children after ten years of attempting childbearing compared to males who have been proven fertile, and to assess the relationship between alterations in sperm DNA methylation levels and sperm parameters. A total of 108 semen samples were collected (65 male with infertility problems as cases and 43 proven fertile males as a control), during the period between May 2016 to August 2016. Thirty samples were subjected to 450K arrays as a screening study to identified the differentially methylated CpGs between case and control groups, and then three CpG sites have the highest difference in the methylation level (cg19169023, cg22963027, and cg21575308) which are located in TYRO3, CGβ, and FAM189A1 genes, respectively were selected to validate on 78 samples using deep bisulfite sequencing. The result of screening study showed that 15 CpG have significantly and consistently different in the DNA methylation level between cases and controls males. Only 8 of those (DNA methylation difference between 33.34% and 80.31%) do not overlap common annotated SNPs, and all of them linked directly with the genes body and CpG Island (TYRO3, CGβ, FAM189A1, GAA, PRRC2A, MAPK8IP3, PDE11A, and ANXA2). Whereas, the result of validation study showed that variation in methylation levels was found in more than one CpG: the DNA methylation levels at all CpGs tested within the TYRO3 gene-related amplicon showed significant differences in the case group compared to the control group (CpG1, P < 0.003, CpG2, P < 0.0001, CpG3, P < 0.003, and CpG4, P < 0.030). Moreover, one CpGs of the two CpGs tested within the CGβ gene-related amplicon was significantly different (CpG1, P < 0.0001) in the case group compared to the control group. In addition, a significant difference was found at two CpGs tested within the FAM189A1 gene-related amplicon between case and control groups (CpG1, P < 0.004, and CpG2, P < 0.002). A negative significant correlation was found between the percentages of total sperm motility, percentages of sperm progressive motility, percentages of sperm non-progressive motility, and percentages of sperm normal form and the methylation levels at CpG1 of the FAM189A1 gene-related amplicon (P < 0.0001, P < 0.002, P < 0.0001, and P < 0.001, respectively). This study identified CpGs related to TYRO3, CGβ, and FAM189A1 genes have alterations at methylation levels in sperm DNA from males, who have been unable to have children after ten years of attempting childbearing compared to proven fertile males. In addition, an association between changes in the methylation level at CpGs in FAM189A1 gene-related amplicon and sperm motility was found.