Mapping the metabolic perturbations associated with palmitate-induced oxidative stress and development of insulin resistance in skeletal muscle cells

Abstract

The development of insulin resistance (IR) in the skeletal muscle has been identified as one of the hallmarks of Type 2 diabetes mellitus (T2DM). Studies have shown that palmitic acid (PA), a saturated free fatty acid (FFA), can contribute to the development of IR in various insulin-responsive tissues via the induction of oxidative stress and mitochondrial dysfunction. The specific molecular mechanisms and metabolic changes that lead to IR development are not completely defined, and a better understanding of these mechanisms is needed. Our study aims to identify metabolites linked with the development of IR in skeletal muscles using PA and map the major metabolic pathways involved. Rat-derived L6 myotubes were exposed to PA to establish IR. Cellular and biochemical experiments were performed, and the metabolic perturbations associated with the induction of oxidative stress and IR were identified using 1H NMR-based metabolomics. PA exposure was associated with a loss of cellular viability due to lipid accumulation in the myotubes. This was associated with an induction of oxidative stress, loss of function, and reduced mitochondrial membrane potential. The metabolic fingerprint linked with the development of oxidative stress and IR in skeletal muscles was identified, wherein significant perturbations in the levels of methanol, dimethylamine, serine, lysine, proline, glycerol, and alanine (p < 0.05) were observed. The dysregulated metabolites and pathways identified in this study can be proposed as biomarkers for detecting palmitate-induced oxidative stress and development of IR in the skeletal myotubes – phenotypes associated with T2DM and related metabolic disorders.