Deoxyribonucleic acid methylation signatures in sperm deoxyribonucleic acid fragmentation.

ABSTRACT

OBJECTIVE: To evaluate Deoxyribonucleic acid (DNA) methylation patterns in sperm from men with differential levels of sperm DNA fragmentation index (DFI). DESIGN: Prospective study. SETTING: University-affiliated reproductive medicine center. PATIENT(S) A total of 278 male patients consulting for couple infertility were recruited from the First Affiliated Hospital of Wenzhou Medical University. INTERVENTION(S) None. MAIN OUTCOME MEASURE(S) Genome-wide DNA methylation analysis was performed using Infinium MethylationEPIC BeadChip on spermatozoal DNA from 20 male patients. Differentially methylated regions (DMRs) were identified and validated using targeted bisulfite amplicon sequencing in spermatozoal DNA from 266 males. RESULT(S) Unsupervised hierarchical clustering analysis revealed three main clusters corresponding to sperm DFI levels (low, medium, or high). Between-cluster comparisons identified 959 (medium-low), 738 (high-medium), and 937 (high-low) DMRs. Sixty-six DMRs were validated in the 266-sample cohort, of which nine CpG fragments corresponding to nine genes (BLCAP, DIRAS3, FAM50B, GNAS, MEST, TSPAN32, PSMA8, SYCP1, and TEX12) exhibited significantly altered methylation in those with high DFI (≥25%) compared with those with low DFI (<25%). CONCLUSION(S) We identified and validated a distinct DNA methylation signature associated with sperm DNA damage in a large, unselected cohort. These results indicate that sperm DNA damage may affect DNA methylation patterns in human sperm.