Next-generation DNA methylation sequencing: loci and regions differentially methylated in adolescents with chronic...

DNA methylation (DNAm) may link environmental exposures to pain susceptibility. We examined preoperative DNAm patterns (using next-generation enzymatic-methylation sequencing) associated with chronic postsurgical pain (CPSP), a major biopsychosocial problem in adolescents undergoing musculoskeletal surgeries, recruited across six sites (n = 166; 15.5 (IQR 14.3-16.8) years; 51% male). Pain and functional measures were followed longitudinally. CPSP was defined as pain>3/10 beyond two months post-surgery. We identified 289 differentially methylated loci (DML; HB p < 0.1) that satisfied robustness criteria after bootstrapping, and 20 regions (DMR) (FDR p < 0.05) associated with CPSP. Using CPSP-specific background, DMLs, annotated to 57 genes, were enriched for biological processes (Cellular response to cAMP (p = 0.001), neuronal action potential (p = 0.01), sodium ion transmembrane transport (p = 0.03), potassium ion transmembrane transport (P = 0.035) and regulation of postsynaptic membrane potential (P = 0.041)), molecular functions (Intracellular camp-activated cation channel activity (p = 0.001), cAMP binding (p = 0.003), voltage-gated sodium channel activity (p = 0.01), and voltage-gated potassium channel activity (p = 0.02)), and cellular components (HCN channel complex (p = 0.002), presynaptic active zone membrane (p = 0.006), and postsynaptic membrane (p = 0.049)). DMRs did not enrich gene pathways but showed transcription factor motif enrichment for stress response (TGF-β/SMAD), neuronal differentiation/plasticity (NR4A/TEAD), inflammation/immunity (STATs), and circadian signaling (RORA/RORB/NPAS2). Study findings suggest potential DNAm signatures associated with CPSP and generate hypotheses regarding their possible role in CPSP development.