Inhibition of aging-induced DNA hypermethylation by si-Dnmt3a/3b in pre-implantation embryos improves aberrant social behavior in offspring

Advanced paternal age constitutes a noteworthy risk factor for neurodevelopmental disorders in progeny, encompassing conditions such as schizophrenia, autism, and atypical social behavior. Nonetheless, the precise underlying mechanisms remain inadequately comprehended. In this study, we delved into the alterations of DNA methylation induced by aging in sperm and pre-implantation embryos of male mice. A total of 3909 Differentially Methylated Regions (DMRs) were identified in sperm from aged male mice compared to young group. In addition, the overall DNA methylation in androgenetic 2-cell embryos exhibited a pronounced increase in aged group, leading to altered expression of genes related to neuropsychiatric disorders. Interestingly, a total of 242 shared DMRs were identified through the overlap of the sperm DMR sets and the 2-cell embryo DMR sets. This finding suggests the plausible involvement of these shared DMRs in the intergenerational transmission of epigenetic traits. Furthermore, F1 male mice from aged group exhibited a marked decrease in sociability and displayed DNA methylation alterations associated with nerve signal transduction components in their brain tissues. Intriguingly, inhibition of DNA methyltransferases (DNMT3A/3B) by siRNA in pre-implantation embryos improved abnormal social behaviors in F1 males from aged fathers, with concomitant changes in the expression of genes related to nerve development detected in 4-cell embryos. Our study indicates that male aging exert an influence not only on DNA methylation modification in sperm and pre-implantation embryo, but also on neurobehavioral abnormalities of their offspring. Repairing DNA methylation in pre-implantation embryos may offer a promising avenue for ameliorating abnormal social behavior in offspring.