title: Selective Enhancement of Insulin Sensitivity in the Endothelium In Vivo Reveals a Novel Proatherosclerotic Signaling Loop.
abstract: BACKGROUND
  In the endothelium, insulin stimulates endothelial NO synthase (eNOS) to generate the antiatherosclerotic signaling radical NO. Insulin-resistant type 2 diabetes mellitus is associated with reduced NO availability and accelerated atherosclerosis. The effect of enhancing endothelial insulin sensitivity on NO availability is unclear.
  
  
  OBJECTIVE
  To answer this question, we generated a mouse with endothelial cell (EC)-specific overexpression of the human insulin receptor (hIRECO) using the Tie2 promoter-enhancer.
  
  
  RESULTS
  hIRECO demonstrated significant endothelial dysfunction measured by blunted endothelium-dependent vasorelaxation to acetylcholine, which was normalized by a specific Nox2 NADPH oxidase inhibitor. Insulin-stimulated phosphorylation of protein kinase B was increased in hIRECO EC as was Nox2 NADPH oxidase-dependent generation of superoxide, whereas insulin-stimulated and shear stress-stimulated eNOS activations were blunted. Phosphorylation at the inhibitory residue Y657 of eNOS and expression of proline-rich tyrosine kinase 2 that phosphorylates this residue were significantly higher in hIRECO EC. Inhibition of proline-rich tyrosine kinase 2 improved insulin-induced and shear stress-induced eNOS activation in hIRECO EC.
  
  
  CONCLUSIONS
  Enhancing insulin sensitivity specifically in EC leads to a paradoxical decline in endothelial function, mediated by increased tyrosine phosphorylation of eNOS and excess Nox2-derived superoxide. Increased EC insulin sensitivity leads to a proatherosclerotic imbalance between NO and superoxide. Inhibition of proline-rich tyrosine kinase 2 restores insulin-induced and shear stress-induced NO production. This study demonstrates for the first time that increased endothelial insulin sensitivity leads to a proatherosclerotic imbalance between NO and superoxide.
authors.affiliation: From the Leeds Institute of Cardiovascular and Metabolic Medicine, University of Leeds, United Kingdom (H.V., N.Y.Y., A.S., H.I., N.H., A.M.N.W., A.S., N.M., S.G., P. Shah, P. Sukumar, K.E.P., P.J.G., J.L., D.J.B., S.B.W., R.M.C., M.T.K.); Division of Medicine, Department of Metabolism & Experimental Therapeutics, University College London, United Kingdom (M.C.G.); and British Heart Foundation Centre of Research Excellence, King's College London, United Kingdom (A.M.S., C.X.C.S.). h.viswambharan@leeds.ac.uk.
authors.forename: Hema
authors.initials: H
authors.lastname: Viswambharan
authors.affiliation: From the Leeds Institute of Cardiovascular and Metabolic Medicine, University of Leeds, United Kingdom (H.V., N.Y.Y., A.S., H.I., N.H., A.M.N.W., A.S., N.M., S.G., P. Shah, P. Sukumar, K.E.P., P.J.G., J.L., D.J.B., S.B.W., R.M.C., M.T.K.); Division of Medicine, Department of Metabolism & Experimental Therapeutics, University College London, United Kingdom (M.C.G.); and British Heart Foundation Centre of Research Excellence, King's College London, United Kingdom (A.M.S., C.X.C.S.).
authors.forename: Nadira Y
authors.initials: NY
authors.lastname: Yuldasheva
authors.affiliation: From the Leeds Institute of Cardiovascular and Metabolic Medicine, University of Leeds, United Kingdom (H.V., N.Y.Y., A.S., H.I., N.H., A.M.N.W., A.S., N.M., S.G., P. Shah, P. Sukumar, K.E.P., P.J.G., J.L., D.J.B., S.B.W., R.M.C., M.T.K.); Division of Medicine, Department of Metabolism & Experimental Therapeutics, University College London, United Kingdom (M.C.G.); and British Heart Foundation Centre of Research Excellence, King's College London, United Kingdom (A.M.S., C.X.C.S.).
authors.forename: Anshuman
authors.initials: A
authors.lastname: Sengupta
authors.affiliation: From the Leeds Institute of Cardiovascular and Metabolic Medicine, University of Leeds, United Kingdom (H.V., N.Y.Y., A.S., H.I., N.H., A.M.N.W., A.S., N.M., S.G., P. Shah, P. Sukumar, K.E.P., P.J.G., J.L., D.J.B., S.B.W., R.M.C., M.T.K.); Division of Medicine, Department of Metabolism & Experimental Therapeutics, University College London, United Kingdom (M.C.G.); and British Heart Foundation Centre of Research Excellence, King's College London, United Kingdom (A.M.S., C.X.C.S.).
authors.forename: Helen
authors.initials: H
authors.lastname: Imrie
authors.affiliation: From the Leeds Institute of Cardiovascular and Metabolic Medicine, University of Leeds, United Kingdom (H.V., N.Y.Y., A.S., H.I., N.H., A.M.N.W., A.S., N.M., S.G., P. Shah, P. Sukumar, K.E.P., P.J.G., J.L., D.J.B., S.B.W., R.M.C., M.T.K.); Division of Medicine, Department of Metabolism & Experimental Therapeutics, University College London, United Kingdom (M.C.G.); and British Heart Foundation Centre of Research Excellence, King's College London, United Kingdom (A.M.S., C.X.C.S.).
authors.forename: Matthew C
authors.initials: MC
authors.lastname: Gage
authors.affiliation: From the Leeds Institute of Cardiovascular and Metabolic Medicine, University of Leeds, United Kingdom (H.V., N.Y.Y., A.S., H.I., N.H., A.M.N.W., A.S., N.M., S.G., P. Shah, P. Sukumar, K.E.P., P.J.G., J.L., D.J.B., S.B.W., R.M.C., M.T.K.); Division of Medicine, Department of Metabolism & Experimental Therapeutics, University College London, United Kingdom (M.C.G.); and British Heart Foundation Centre of Research Excellence, King's College London, United Kingdom (A.M.S., C.X.C.S.).
authors.forename: Natalie
authors.initials: N
authors.lastname: Haywood
authors.affiliation: From the Leeds Institute of Cardiovascular and Metabolic Medicine, University of Leeds, United Kingdom (H.V., N.Y.Y., A.S., H.I., N.H., A.M.N.W., A.S., N.M., S.G., P. Shah, P. Sukumar, K.E.P., P.J.G., J.L., D.J.B., S.B.W., R.M.C., M.T.K.); Division of Medicine, Department of Metabolism & Experimental Therapeutics, University College London, United Kingdom (M.C.G.); and British Heart Foundation Centre of Research Excellence, King's College London, United Kingdom (A.M.S., C.X.C.S.).
authors.forename: Andrew M N
authors.initials: AM
authors.lastname: Walker
authors.affiliation: From the Leeds Institute of Cardiovascular and Metabolic Medicine, University of Leeds, United Kingdom (H.V., N.Y.Y., A.S., H.I., N.H., A.M.N.W., A.S., N.M., S.G., P. Shah, P. Sukumar, K.E.P., P.J.G., J.L., D.J.B., S.B.W., R.M.C., M.T.K.); Division of Medicine, Department of Metabolism & Experimental Therapeutics, University College London, United Kingdom (M.C.G.); and British Heart Foundation Centre of Research Excellence, King's College London, United Kingdom (A.M.S., C.X.C.S.).
authors.forename: Anna
authors.initials: A
authors.lastname: Skromna
authors.affiliation: From the Leeds Institute of Cardiovascular and Metabolic Medicine, University of Leeds, United Kingdom (H.V., N.Y.Y., A.S., H.I., N.H., A.M.N.W., A.S., N.M., S.G., P. Shah, P. Sukumar, K.E.P., P.J.G., J.L., D.J.B., S.B.W., R.M.C., M.T.K.); Division of Medicine, Department of Metabolism & Experimental Therapeutics, University College London, United Kingdom (M.C.G.); and British Heart Foundation Centre of Research Excellence, King's College London, United Kingdom (A.M.S., C.X.C.S.).
authors.forename: Natallia
authors.initials: N
authors.lastname: Makova
authors.affiliation: From the Leeds Institute of Cardiovascular and Metabolic Medicine, University of Leeds, United Kingdom (H.V., N.Y.Y., A.S., H.I., N.H., A.M.N.W., A.S., N.M., S.G., P. Shah, P. Sukumar, K.E.P., P.J.G., J.L., D.J.B., S.B.W., R.M.C., M.T.K.); Division of Medicine, Department of Metabolism & Experimental Therapeutics, University College London, United Kingdom (M.C.G.); and British Heart Foundation Centre of Research Excellence, King's College London, United Kingdom (A.M.S., C.X.C.S.).
authors.forename: Stacey
authors.initials: S
authors.lastname: Galloway
authors.affiliation: From the Leeds Institute of Cardiovascular and Metabolic Medicine, University of Leeds, United Kingdom (H.V., N.Y.Y., A.S., H.I., N.H., A.M.N.W., A.S., N.M., S.G., P. Shah, P. Sukumar, K.E.P., P.J.G., J.L., D.J.B., S.B.W., R.M.C., M.T.K.); Division of Medicine, Department of Metabolism & Experimental Therapeutics, University College London, United Kingdom (M.C.G.); and British Heart Foundation Centre of Research Excellence, King's College London, United Kingdom (A.M.S., C.X.C.S.).
authors.forename: Pooja
authors.initials: P
authors.lastname: Shah
authors.affiliation: From the Leeds Institute of Cardiovascular and Metabolic Medicine, University of Leeds, United Kingdom (H.V., N.Y.Y., A.S., H.I., N.H., A.M.N.W., A.S., N.M., S.G., P. Shah, P. Sukumar, K.E.P., P.J.G., J.L., D.J.B., S.B.W., R.M.C., M.T.K.); Division of Medicine, Department of Metabolism & Experimental Therapeutics, University College London, United Kingdom (M.C.G.); and British Heart Foundation Centre of Research Excellence, King's College London, United Kingdom (A.M.S., C.X.C.S.).
authors.forename: Piruthivi
authors.initials: P
authors.lastname: Sukumar
authors.affiliation: From the Leeds Institute of Cardiovascular and Metabolic Medicine, University of Leeds, United Kingdom (H.V., N.Y.Y., A.S., H.I., N.H., A.M.N.W., A.S., N.M., S.G., P. Shah, P. Sukumar, K.E.P., P.J.G., J.L., D.J.B., S.B.W., R.M.C., M.T.K.); Division of Medicine, Department of Metabolism & Experimental Therapeutics, University College London, United Kingdom (M.C.G.); and British Heart Foundation Centre of Research Excellence, King's College London, United Kingdom (A.M.S., C.X.C.S.).
authors.forename: Karen E
authors.initials: KE
authors.lastname: Porter
authors.affiliation: From the Leeds Institute of Cardiovascular and Metabolic Medicine, University of Leeds, United Kingdom (H.V., N.Y.Y., A.S., H.I., N.H., A.M.N.W., A.S., N.M., S.G., P. Shah, P. Sukumar, K.E.P., P.J.G., J.L., D.J.B., S.B.W., R.M.C., M.T.K.); Division of Medicine, Department of Metabolism & Experimental Therapeutics, University College London, United Kingdom (M.C.G.); and British Heart Foundation Centre of Research Excellence, King's College London, United Kingdom (A.M.S., C.X.C.S.).
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Grant
authors.affiliation: From the Leeds Institute of Cardiovascular and Metabolic Medicine, University of Leeds, United Kingdom (H.V., N.Y.Y., A.S., H.I., N.H., A.M.N.W., A.S., N.M., S.G., P. Shah, P. Sukumar, K.E.P., P.J.G., J.L., D.J.B., S.B.W., R.M.C., M.T.K.); Division of Medicine, Department of Metabolism & Experimental Therapeutics, University College London, United Kingdom (M.C.G.); and British Heart Foundation Centre of Research Excellence, King's College London, United Kingdom (A.M.S., C.X.C.S.).
authors.forename: Ajay M
authors.initials: AM
authors.lastname: Shah
authors.affiliation: From the Leeds Institute of Cardiovascular and Metabolic Medicine, University of Leeds, United Kingdom (H.V., N.Y.Y., A.S., H.I., N.H., A.M.N.W., A.S., N.M., S.G., P. Shah, P. Sukumar, K.E.P., P.J.G., J.L., D.J.B., S.B.W., R.M.C., M.T.K.); Division of Medicine, Department of Metabolism & Experimental Therapeutics, University College London, United Kingdom (M.C.G.); and British Heart Foundation Centre of Research Excellence, King's College London, United Kingdom (A.M.S., C.X.C.S.).
authors.forename: Celio X C
authors.initials: CX
authors.lastname: Santos
authors.affiliation: From the Leeds Institute of Cardiovascular and Metabolic Medicine, University of Leeds, United Kingdom (H.V., N.Y.Y., A.S., H.I., N.H., A.M.N.W., A.S., N.M., S.G., P. Shah, P. Sukumar, K.E.P., P.J.G., J.L., D.J.B., S.B.W., R.M.C., M.T.K.); Division of Medicine, Department of Metabolism & Experimental Therapeutics, University College London, United Kingdom (M.C.G.); and British Heart Foundation Centre of Research Excellence, King's College London, United Kingdom (A.M.S., C.X.C.S.).
authors.forename: Jing
authors.initials: J
authors.lastname: Li
authors.affiliation: From the Leeds Institute of Cardiovascular and Metabolic Medicine, University of Leeds, United Kingdom (H.V., N.Y.Y., A.S., H.I., N.H., A.M.N.W., A.S., N.M., S.G., P. Shah, P. Sukumar, K.E.P., P.J.G., J.L., D.J.B., S.B.W., R.M.C., M.T.K.); Division of Medicine, Department of Metabolism & Experimental Therapeutics, University College London, United Kingdom (M.C.G.); and British Heart Foundation Centre of Research Excellence, King's College London, United Kingdom (A.M.S., C.X.C.S.).
authors.forename: David J
authors.initials: DJ
authors.lastname: Beech
authors.affiliation: From the Leeds Institute of Cardiovascular and Metabolic Medicine, University of Leeds, United Kingdom (H.V., N.Y.Y., A.S., H.I., N.H., A.M.N.W., A.S., N.M., S.G., P. Shah, P. Sukumar, K.E.P., P.J.G., J.L., D.J.B., S.B.W., R.M.C., M.T.K.); Division of Medicine, Department of Metabolism & Experimental Therapeutics, University College London, United Kingdom (M.C.G.); and British Heart Foundation Centre of Research Excellence, King's College London, United Kingdom (A.M.S., C.X.C.S.).
authors.forename: Stephen B
authors.initials: SB
authors.lastname: Wheatcroft
authors.affiliation: From the Leeds Institute of Cardiovascular and Metabolic Medicine, University of Leeds, United Kingdom (H.V., N.Y.Y., A.S., H.I., N.H., A.M.N.W., A.S., N.M., S.G., P. Shah, P. Sukumar, K.E.P., P.J.G., J.L., D.J.B., S.B.W., R.M.C., M.T.K.); Division of Medicine, Department of Metabolism & Experimental Therapeutics, University College London, United Kingdom (M.C.G.); and British Heart Foundation Centre of Research Excellence, King's College London, United Kingdom (A.M.S., C.X.C.S.).
authors.forename: Richard M
authors.initials: RM
authors.lastname: Cubbon
authors.affiliation: From the Leeds Institute of Cardiovascular and Metabolic Medicine, University of Leeds, United Kingdom (H.V., N.Y.Y., A.S., H.I., N.H., A.M.N.W., A.S., N.M., S.G., P. Shah, P. Sukumar, K.E.P., P.J.G., J.L., D.J.B., S.B.W., R.M.C., M.T.K.); Division of Medicine, Department of Metabolism & Experimental Therapeutics, University College London, United Kingdom (M.C.G.); and British Heart Foundation Centre of Research Excellence, King's College London, United Kingdom (A.M.S., C.X.C.S.).
authors.forename: Mark T
authors.initials: MT
authors.lastname: Kearney
mesh_terms: D000818:Animals; D050197:Atherosclerosis / Q000378:metabolism* / Q000473:pathology; D002478:Cells, Cultured; D042783:Endothelial Cells / Q000378:metabolism* / Q000473:pathology; D004730:Endothelium, Vascular / Q000378:metabolism* / Q000473:pathology; D061307:Human Umbilical Vein Endothelial Cells; D006801:Humans; D007333:Insulin Resistance / Q000502:physiology*; D008297:Male; D051379:Mice; D057507:Mice, 129 Strain; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D009924:Organ Culture Techniques; D015398:Signal Transduction / Q000502:physiology*
keywords: diabetes mellitus; insulin; insulin resistance; reactive oxygen species; superoxide