Poster Presentation 43rd Lorne Genome Conference 2022

Skeletal muscle methylome and transcriptome integration reveals profound sex differences related to muscle function and substrate metabolism   (#154)

Shanie Landen 1 , Macsue Jacques 1 , Danielle Hiam 2 , Javier Alvarez Romero 1 , Nicholas R Harvey 3 , Larisa M Haupt 3 , Lyn R Griffiths 3 , Kevin J Ashton 4 , Severine Lamon 2 , Sarah Voisin 1 , Nir Eynon 1
  1. Victoria University, Melbourne, VICTORIA, Australia
  2. Deakin University, Melbourne, VIC
  3. Queensland University of Technology, Brisbane, QLD
  4. Bond University, Gold Coast, QLD

Nearly all human complex traits and diseases exhibit some degree of sex differences, with epigenetics being one of the main contributing factors. Various tissues display sex differences in DNA methylation; however, this has not yet been explored in skeletal muscle, despite skeletal muscle being among the tissues with the most transcriptomic sex differences. For the first time, we investigated the effect of sex on autosomal DNA methylation in human skeletal muscle across three independent cohorts (Gene SMART, FUSION, and GSE38291) using a meta-analysis approach, totaling 369 human muscle samples (222 males and 147 females), and integrated this with known sex-biased transcriptomics. We found 10,240 differentially methylated regions, 94% of which were hypomethylated in males, and gene set enrichment analysis revealed enrichment of pathways involved in muscle contraction and substrate metabolism. We investigated biological factors underlying DNA methylation sex differences and found that circulating hormones were not associated with differential methylation at sex-biased DNA methylation loci; however, these sex-specific loci were enriched for binding sites of hormone-related transcription factors. Fiber type proportions were associated with differential methylation across the genome, as well as across 16% of sex-biased DNA methylation loci. Integration of DNA methylomic results with transcriptomic data from the GTEx database and the FUSION cohort revealed 326 autosomal genes that display sex differences at both the epigenome and transcriptome levels. Importantly, transcriptional sex-biased genes were overrepresented among epigenetic sex-biased genes, suggesting differential DNA methylation and gene expression between male and female muscle are functionally linked. Finally, we validated expression of three genes with large effect sizes in the Gene SMART cohort with qPCR. In conclusion, we uncovered 8420 genes that exhibit DNA methylation differences between males and females in human skeletal muscle that may modulate mechanisms controlling muscle metabolism and health.