Palmitoylethanolamide (PEA) regulates cell cycle progression and promotes an anti-inflammatory transcriptomic...

Palmitoylethanolamide (PEA) is an endogenous lipid mediator with immunomodulatory actions, yet its effects in skeletal muscle remain poorly defined. We examined whether PEA influences myogenesis and profiled the acute transcriptomic response of differentiated C2C12 myotubes to 10 μM PEA. PEA decreased myotube number (90.3 ± 10.6 vs. 112.6 ± 10.1 control) while increasing nuclear fusion index (37.8 ± 5.7% vs. 30.7 ± 3.2%); myotube area was unchanged. In myoblasts, 24 h PEA increased G₀/G₁ (48.2 ± 1.2% vs. 42.3 ± 1.9%) and reduced S-phase (21.7 ± 1.2% vs. 25.5 ± 1.2%), consistent with G₁ arrest. RNA sequencing identified 1952 differentially expressed genes enriched for cytokine-receptor interactions and inflammatory signaling. PEA downregulated NF-κB target cytokines while upregulating interferon-related and chemokine genes, indicating an anti-inflammatory/immune-priming profile. N-acylethanolamine acid amidase was highly expressed and induced, whereas fatty acid amide hydrolase remained low and unchanged, suggesting muscle-specific reliance on NAAA metabolism. These data show that PEA biases skeletal muscle toward a less proliferative but more fused and inflammation-resolving phenotype, with transcriptional reprogramming of immune pathways and preferential NAAA engagement. These findings motivate in vivo studies to test whether such actions benefit muscle regeneration, adaptation, or anti-atrophy interventions.