title: Severe insulin resistance alters metabolism in mesenchymal progenitor cells.
abstract: Donohue syndrome (DS) is characterized by severe insulin resistance due to mutations in the insulin receptor (INSR) gene. To identify molecular defects contributing to metabolic dysregulation in DS in the undifferentiated state, we generated mesenchymal progenitor cells (MPCs) from induced pluripotent stem cells derived from a 4-week-old female with DS and a healthy newborn male (control). INSR mRNA and protein were significantly reduced in DS MPC (for β-subunit, 64% and 89% reduction, respectively, P < .05), but IGF1R mRNA and protein did not differ vs control. Insulin-stimulated phosphorylation of INSR or the downstream substrates insulin receptor substrate 1 and protein kinase B did not differ, but ERK phosphorylation tended to be reduced in DS (32% decrease, P = .07). By contrast, IGF-1 and insulin-stimulated insulin-like growth factor 1 (IGF-1) receptor phosphorylation were increased in DS (IGF-1, 8.5- vs 4.5-fold increase; INS, 11- vs 6-fold; P < .05). DS MPC tended to have higher oxygen consumption in both the basal state (87% higher, P =.09) and in response to the uncoupler carbonyl cyanide-p-triflouromethoxyphenylhydrazone (2-fold increase, P =.06). Although mitochondrial DNA or mass did not differ, oxidative phosphorylation protein complexes III and V were increased in DS (by 37% and 6%, respectively; P < .05). Extracellular acidification also tended to increase in DS (91% increase, P = .07), with parallel significant increases in lactate secretion (34% higher at 4 h, P < .05). In summary, DS MPC maintain signaling downstream of the INSR, suggesting that IGF-1R signaling may partly compensate for INSR mutations. However, alterations in receptor expression and pathway-specific defects in insulin signaling, even in undifferentiated cells, can alter cellular oxidative metabolism, potentially via transcriptional mechanisms.
authors: Research Division (B.B., A.B., V.T., R.K., C.R.K., M.-E.P.), Joslin Diabetes Center, Boston, Massachusetts 02215; Department of Stem Cell and Regenerative Biology (Y.-K.L., C.C.), Harvard University, Cambridge, Massachusetts 02138; and Center for Regenerative Medicine and Cardiovascular Research Center (Y.-K.L., C.C.), Massachusetts General Hospital, Boston, Massachusetts 02114.
authors: Bharti
authors: B
authors: Balhara
authors: Alison
authors: A
authors: Burkart
authors: Vehap
authors: V
authors: Topcu
authors: Youn-Kyoung
authors: YK
authors: Lee
authors: Chad
authors: C
authors: Cowan
authors: C Ronald
authors: CR
authors: Kahn
authors: Mary-Elizabeth
authors: ME
authors: Patti
mesh_terms: D002470:Cell Survival / Q000502:physiology*; D002478:Cells, Cultured; D004272:DNA, Mitochondrial / Q000378:metabolism; D005260:Female; D005434:Flow Cytometry; D006801:Humans; D057026:Induced Pluripotent Stem Cells / Q000166:cytology* / Q000378:metabolism*; D007223:Infant; D007231:Infant, Newborn; D007333:Insulin Resistance / Q000502:physiology*; D008297:Male; D059630:Mesenchymal Stem Cells / Q000166:cytology* / Q000378:metabolism*
chemical_list: D004272:DNA, Mitochondrial