The proteomic signature of insulin-resistant human skeletal muscle reveals increased glycolytic and decreased mitochondrial enzymes

Abstract

Aims/hypothesis The molecular mechanisms underlying insulin resistance in skeletal muscle are incompletely understood. Here, we aimed to obtain a global picture of changes in protein abundance in skeletal muscle in obesity and type 2 diabetes, and those associated with whole-body measures of insulin action. Methods Skeletal muscle biopsies were obtained from ten healthy lean (LE), 11 obese non-diabetic (OB), and ten obese type 2 diabetic participants before and after hyperinsulinaemic-euglycaemic clamps. Quantitative proteome analysis was performed by two-dimensional differential-gel electrophoresis and tandem-mass-spectrometry-based protein identification.Results Forty-four protein spots displayed significant (p< 0.05) changes in abundance by at least a factor of 1.5 between groups. Several proteins were identified in multiple spots, suggesting post-translational modifications. Multiple spots containing glycolytic and fast-muscle proteins showed increased abundance, whereas spots with mitochondrial and slow-muscle proteins were downregulated in the OB and obese type 2 diabetic groups compared with the LE group. No differences in basal levels of myosin heavy chains were observed. The abundance of multiple spots representing glycolytic and fast-muscle proteins correlated negatively with insulin action on glucose disposal, glucose oxidation and lipid oxidation, while several spots with proteins J. Giebelstein, G. Poschmann and K. Højlund contributed equally to this work. involved in oxidative metabolism and mitochondrial function correlated positively with these whole-body measures of insulin action. Conclusions/interpretation Our data suggest that increased glycolytic and decreased mitochondrial protein abundance together with a shift in muscle properties towards a fasttwitch pattern in the absence of marked changes in fibretype distribution contribute to insulin resistance in obesity with and without type 2 diabetes. The roles of several differentially expressed or post-translationally modified proteins remain to be elucidated.

Differential Proteomic Analysis of the Pancreas of Diabetic db/db Mice Reveals the Proteins Involved in the Development of Complications of Diabetes Mellitus

“…we use the full pancreas from genetically modified db / db mice. PGAM1 is an enzyme involved in the second phase of glycolysis, although there are some discrepancies as to whether this metabolic pathway is increased or decreased at high concentrations of glucose, it is clear that in T2DM this pathway is disturbed [13,14,15]. At least in type 1 diabetes, it has been demonstrated that multiple alterations in the expression of proteins involved in oxidative stress, aerobic and anaerobic glycolysis and intracellular signaling in human skin were reversed after kidney-pancreas transplant [16].…”

“…There is controversy on whether the catabolic hexose-processing enzymes, including glucose, decrease or increase in diabetes, as wide alterations have been observed [13,14,15]. …”

Effect of testosterone on markers of mitochondrial oxidative phosphorylation and lipid metabolism in muscle of aging men with subnormal bioavailable testosterone

“…In aging, obesity, and type 2 diabetes, insulin resistance in skeletal muscle has been linked to a number of abnormalities in mitochondrial oxidative metabolism (7,8,9,10). This includes transcriptomic and proteomic evidence of a coordinated downregulation of genes and proteins involved in oxidative phosphorylation (OxPhos) in insulin-resistant skeletal muscle (11,12,13,14) as well as reduced expression of the peroxisome proliferatoractivated receptor gamma coactivator 1 alpha gene (PGC1a), which plays a key role in mitochondrial biogenesis (13,14). The decrease in mitochondrial oxidative capacity has been proposed to cause reduced lipid oxidation with subsequent accumulation of lipids and lipid metabolites, which in turn can inhibit insulin signaling to glucose transport and glycogen synthesis (6,15), as observed in skeletal muscle in obesity and type 2 diabetes (16,17,18).…”

Proteomics of Skeletal Muscle: Focus on Insulin Resistance and Exercise Biology

“…Over the last decades, several research groups have performed skeletal muscle proteome analysis from diabetic patients and rodent models of diabetes [68,69,70,71]. These pioneering studies have already begun to advance our understanding of skeletal muscle insulin resistance.…”

“…For example, Giebelstein et al showed that the abundance of glycolytic enzymes was up-regulated, while mitochondrial proteins were down-regulated in skeletal muscle from insulin-resistant subjects. Interestingly, these changes were associated with shift in muscle properties towards a fast-twitch pattern [68]. Numerous proteomics studies suggest pivotal role for mitochondrial function in development of Type 2 diabetes.…”