1135-P: Type 2 Diabetes Modulates DNA Methylation in Human Sperm

Paternal obesity and diabetes are associated with cardiometabolic risk in offspring. To test the hypothesis that paternal metabolism could exert these effects via modulation of the sperm epigenome, we collected motile sperm at two study visits 3 months apart in men with and without T2D (NCT03860558). Sperm DNA methylation was quantified in 32 samples using the Infinium MethylationEPIC array. HbA1c was higher in men with T2D vs. controls (7.6±1.1% vs. 5.2±0.2%, n=9 vs. 7, p<0.0001). Age (49.6±7.5 vs. 40.9±12.3 years, p=0.1), BMI (34.4±6.7 vs. 30.3±4.0 kg/m², p=0.17), waist circumference and fat % were similar. There were no differences in sperm concentration or motility, testosterone, LH, estradiol, or prolactin levels. Methylation data were pre-processed using Partek Genomics Suite 7.19. After filtering cross-reactive probes and probes overlapping with SNP, 790508 probes were analyzed. Two-way ANOVA (disease group/time as factors) revealed 7 CpG sites differentially methylated between control and T2D (FDR q<0.05, differences in beta>0.2), including sites annotated to SLFN5, MMAA, and LOC101927829. All 7 sites were hypermethylated in T2D, with mean difference in beta of 26.4%. Paired analysis between study visits for individual participants revealed no significant CpG, indicating stability of sperm methylation over time. Genes annotated to differentially methylated CpG at both study visits (n=89, nominal p<0.01) were enriched for genes involved in morphogenesis and neuron development; the majority of these CpG also had higher methylation in T2D. In a linear regression model, 10 CpG sites showed positive and 2 sites showed negative association with HbA1c (FDR q<0.05).

In summary, DNA methylation is altered in motile sperm from men with T2D, with hypermethylation at significant CpG sites. These alterations may reflect differential transcriptional regulation at developmentally important loci, and should be investigated as potential contributors to the impact of paternal metabolism on offspring.