Childhood maltreatment exposure (CME) increases the risk of adverse long-term health consequences for the exposed individual. Animal studies suggest that CME may also influence the health and behaviour in the next generation offspring through CME-driven epigenetic changes in the germ line. Here we investigated the associated between early life stress on the epigenome of sperm in humans with history of CME.

We measured paternal CME using the Trauma and Distress Scale (TADS) questionnaire and mapped sperm-borne sncRNAs expression by small RNA sequencing (small RNA-seq) and DNA methylation (DNAme) in spermatozoa by reduced-representation bisulfite sequencing (RRBS-seq) in males from the FinnBrain Birth Cohort Study. The study design was a (nested) case-control study, high-TADS (TADS ≥ 39, n = 25 for DNAme and n = 14 for small RNA-seq) and low-TADS (TADS ≤ 10, n = 30 for DNAme and n = 16 for small RNA-seq).

We identified 3 genomic regions with differential methylation between low and high-TADS and 68 tRNA-derived small RNAs (tsRNAs) and miRNAs with different levels in males with high CME (False discovery rate, FDR corrected p < 0.05). Of potential interest, we identified differential expression of miRNA hsa-mir-34c-5p and differential methylation levels near the CRTC1 and GBX2 genes, which are documented to control brain development. Our results provide further evidence that early life stress influences the paternal germline epigenome and supports a possible effect in modulating the development of the central nervous system of the next generation.