Transcriptional and Epigenetic Changes Influencing Skeletal Muscle Metabolism in Women With Polycystic Ovary Syndrome

Context: Insulin resistance in skeletal muscle is a major risk factor for the development of type 2
diabetes in women with polycystic ovary syndrome (PCOS). Despite this, the mechanisms underlying
insulin resistance in PCOS are largely unknown.
Objective: To investigate the genome-wide DNA methylation and gene expression patterns in
skeletal muscle from women with PCOS and controls and relate them to phenotypic variations.
Design/Participants: In a case-control study, skeletal muscle biopsies from women with PCOS (n =
17) and age-, weight-, and body mass index‒matched controls (n = 14) were analyzed by array-based
DNA methylation and mRNA expression profiling.
Results: Eighty-five unique transcripts were differentially expressed in muscle from women with PCOS
vs controls, including DYRK1A, SYNPO2, SCP2, and NAMPT. Furthermore, women with PCOS had
reduced expression of genes involved in immune system pathways. Two CpG sites showed differential
DNA methylation after correction for multiple testing. However, an mRNA expression of ;30% of the
differentially expressed genes correlated with DNA methylation levels of CpG sites in or near the gene.
Functional follow-up studies demonstrated that KLF10 is under transcriptional control of insulin,
where insulin promotes glycogen accumulation in myotubes of human muscle cells. Testosterone
downregulates the expression levels of COL1A1 and MAP2K6.
Conclusion: PCOS is associated with aberrant skeletal muscle gene expression with dysregulated
pathways. Furthermore, we identified specific changes in muscle DNA methylation that may affect
gene expression. This study showed that women with PCOS have epigenetic and transcriptional
changes in skeletal muscle that, in part, can explain the metabolic abnormalities seen in
these women.