334-OR: Sex Differences in Protein Phosphorylation in Insulin Resistance in Humans at the Cellular Level

Abstract

Insulin resistance in muscle precedes and predicts type 2 diabetes in offspring of diabetic parents and is also observed in ~25% of the general population. However, whether these changes represent cell autonomous defects or are secondary to changes in circulating factors is unclear. To define possible cell autonomous determinants of insulin resistance, we have utilized induced pluripotent stem cell (iPSC) differentiated into myoblasts from 20 nondiabetic individuals - 10 insulin sensitive (I-Sen) and 10 insulin resistant (I-Res) as assessed using the steady-state plasma glucose approach. While there was no difference in the ability of the iPSCs to differentiate into myoblasts (iMyos), cells from I-Res individuals show impaired insulin signaling, decreased insulin-stimulated glucose uptake, and glycogen synthase activity compared to iMyos from insulin sensitive individuals, indicating that these cells mirror in vitro the alterations seen in vivo. The global phosphoproteomic analysis using LC-MS/MS uncovered a large network of proteins whose phosphorylation was altered in association with insulin resistance, mostly outside the canonical insulin-signaling cascade. We also observed striking differences in the phosphoproteomic signature of iMyos derived from male versus female subjects. Analysis of the proteins involved reveals that male cells show enhanced phosphorylation of proteins associated with transcription, Rho GTPases, SUMOylation, mRNA splicing, and membrane trafficking, whereas females show a dominance of phosphorylation of proteins involved in the cell cycle, chromatin organization, gene expression, and protein ubiquitination. Taken together, these data demonstrate major alterations in cellular signaling underlying insulin resistance, even in the absence of diabetes, and provide evidence of a super-network of cell signaling differences in males and females that must be considered in understanding cellular regulation in health and disease. Disclosure N. Haider: None. J. Lebastchi: None. T. M. Batista: None. H. Pan: None. J. Dreyfuss: None. I. Carcamo-orive: None. J. Knowles: None. C. Kahn: Advisory Panel; Self; ERX Pharmaceuticals, Kaleido Biosciences, Inc., Consultant; Self; Flagship Pioneering, Sana/Cobalt.