Modeling the Spectrum of Human Insulin Resistance Using Induced Pluripotent Stem Cells

Abstract

Induced pluripotent stem cells (iPSCs) represent a unique model to study the genetic components of insulin resistant states in vitro and can be studied in both the undifferentiated and differentiated state. In prior studies we have shown that iPSCs from patients with insulin receptor mutations exhibit altered insulin signaling with reduced insulin-stimulated phosphorylation of IR, IRS, and AKT in iPS-derived myotubes compared to healthy subjects and have reduced insulin stimulation of proliferation and gene expression. We now use iPSCs to characterize the insulin response of type 2 diabetics (T2D) and nondiabetic individuals before and after differentiation to skeletal muscle. The iPSCs from a subgroup of the nondiabetic individuals were further divided into those in the upper and lower quartiles of insulin resistance as determined using steady-state plasma glucose (SSPG) methodology. We find that iPSCs from insulin sensitive controls, insulin resistant (IR) nondiabetics and from patient with type 2 diabetes exhibited similar levels of pluripotency markers and showed similar changes in markers of muscle differentiation through the satellite cell-like and myoblast/myotube stage. This was true for iPSC derived from blood cells and from muscle biopsies. Insulin-induced activation of early signaling steps including phosphorylation of IR, IRS, AKT, ERK and GSK3 showed dose-responsive phosphorylation in the iPSC, as well as myotube stage with significant 10 nM and 100 nM insulin. Importantly, iPSCs differentiated into satellite-like cells displayed insulin resistance at the level of AKT phosphorylation in both the T2D and IR patients (p=0.0134 and p=0.0352). There was also decreased GSK3 phosphorylation in cells from T2D patients (p=0.0325). Thus, iPSC-derived muscle satellite-like cells from T2D and nondiabetic IR individuals retain defects in AKT and GSK3 phosphorylation indicating a level of a genetic or persistent epigenetic signature of insulin resistance in vitro. Disclosure J. Lebastchi: None. T.M. Batista: None. I. Carcamo-Orive: None. A. Krook: None. J.R. Zierath: None. J. Knowles: None. C. Kahn: Advisory Panel; Self; CohBar, ERX Therapeutics, AntriaBio, Inc.. Board Member; Self; Kaleio Biosciences.