Insulin Regulation of Proliferation Involves Activation of AKT and ERK 1/2 Signaling Pathways in Vascular Smooth Muscle Cells

Abstract

This investigation used primary cultured rat vascular smooth muscle cells (VSMCs) to examine the effect of insulin (INS) on proliferation of VSMCs. In this study, we investigated the role of protein kinase B (Akt) and p42/44 mitogen-activated protein kinase (ERK 1/2) signaling pathways in mediating the mitogenic action of INS in VSMCs. Incubation of rat VSMCs with INS (100 nM) for 10 min resulted in an increase of Akt phosphorylation by 6-fold (p<0.001) and ERK 1/2 phosphorylation by 3-fold (p<0.001). Pretreatment for 15 min with 10 μM of PI3K/Akt inhibitor LY294002 or with 20 μM PD98059, inhibitor of ERK 1/2, significantly reduced INS-stimulated Akt and ERK 1/2 phosphorylation by 76 and 75%, respectively. Prolonged treatment of VSMCs with INS for 24 h did not have an effect on either Akt or ERK1/2 phosphorylation. Incubation of rat VSMCs with INS resulted in an increase of VSMCs proliferation by 87% (p<0.001.) The effect of INS on VSMCs proliferation was significantly reduced by 68% by pretreatment with LY294002 (p>0.01) and by 71% (p>0.01) by pretreatment with PD98059. These results indicate that INS acts through Akt and ERK 1/2 signaling pathways to up-regulate proliferation of VSMC's.

Key words

vascular smooth muscle cells - INS - proliferation - Akt - ERK 1/2

References

• 1 Avena R, Mitchell ME, Neville RF. et al . The additive effects of glucose and INS on the proliferation of infragenicular vascular smooth muscle cells.  J Vasc Surg. 1998;  28 1033-1038
• 2 Beckman JA, Creager MA, Libby P. Diabetes and atherosclerosis: epidemiology, pathophysiology, and management.  JAMA. 2002;  287 2570-2581
• 3 Bellacosa A, Testa JR, Staal SP. et al . A retroviral oncogene, Akt, encoding a serine-threonine kinase containing an SH2-like region.  Science. 1991;  254 274-277
• 4 Bobe R, Yin X, Roussanne MC. et al . Evidence for ERK1/2 activation by thrombin that is independent of EGFR transactivation.  Am J Physiol Heart Circ Physiol. 2003;  285 H745-H754
• 5 Boulton TG, Nye SH, Robbins DJ. et al . ERKs: a family of protein-serine/threonine kinases that are activated and tyrosine phosphorylated in response to INS and NGF.  Cell. 1991;  65 663-675
• 6 Burgering BM, Coffer PJ. Protein kinase B (c-Akt) in phosphatidylinositol-3-OH kinase signal transduction.  Nature. 1995;  376 599-602
• 7 Campbell M, Allen WE, Sawyer C. et al . Glucose- potentiated chemotaxis in human vascular smooth muscle is dependent on cross-talk between the PI3 K and MAPK signaling pathways.  Circ Res. 2004;  95 380-388
• 8 Cantley LC. The phosphoinositide 3-kinase pathway.  Science. 2002;  296 1655-1657
• 9 Colwell JA, Jokl R. Vascular thrombosis in diabetes. In: Porte D, Sherwin R, Rifkin H, ed. Diabetes Mellitus: Theory and Practice. 5th ed. Norwalk: Appleton and Lange 1996
• 10 Colwell JA, Lyons TJ, Klein RL. et al .New concepts about the pathogenesis of atherosclerosis and thrombosis in diabetes mellitus. In: Levin MJ, ed. The diabetic Foot. St. Louis: Mosby 1992: 79-114
• 11 Cross DA, Alessi DR, Cohen P. et al . Inhibition of glycogen synthase kinase-3 by INS mediated by protein kinase B.  Nature. 1995;  378 785-789
• 12 Cusi K, Maezono K, Osman A. et al . INS resistance differentially affects the PI 3-kinase- and MAP kinase-mediated signaling in human muscle.  J Clin Invest. 2000;  105 311-320
• 13 Draznin B, Chang L, Leitner JW. et al . INS activates p21Ras and guanine nucleotide releasing factor in cells expressing wild type and mutant INS receptors.  J Biol Chem. 1993;  268 19998-20001
• 14 Dudek H, Datta SR, Franke TF. et al . Regulation of neuronal survival by the serine-threonine protein kinase Akt.  Science. 1997;  275 661-665 , Endocrinology 2004; 145(3): 1151–1160
• 15 Folli F, Kahn CR, Hansen H. et al . Angiotensin II inhibits INS signaling in aortic smooth muscle cells at multiple levels. A potential role for serine phosphorylation in INS/angiotensin II cross-talk.  J Clin Invest. 1997;  100 2158-2169
• 16 Fukuda N, Satoh C, Hu WY. et al . Endogenous angiotensin II suppresses INS signaling in vascular smooth muscle cells from spontaneously hypertensive rats.  J Hypertens. 2001;  19 1651-1658
• 17 Geng YJ, Libby P. Progression of atheroma: a struggle between death and procreation.  Arterioscler Thromb Vasc Biol. 2002;  22 1370-1380
• 18 Gibson TB, Lawrence MC, Gibson CJ. et al . Inhibition of glucose-stimulated activation of extracellular signal-regulated protein kinases 1 and 2 by epinephrine in pancreatic beta-cells.  Diabetes. 2006;  55 ((4)) 1066-1073
• 19 Goetze S, Kintscher U, Kawano H. et al . Tumor necrosis factor alpha inhibits INS-induced mitogenic signaling in vascular smooth muscle cells.  J Biol Chem. 2000;  275 18279-18283
• 20 Hayashi K, Saga H, Chimori Y. et al . Differentiated phenotype of smooth muscle cells depends on signaling pathways through INS-like growth factors and phosphatidylinositol 3-kinase.  J Biol Chem. 1998;  273 28860-28867
• 21 Hsueh WA, Law RE. INS signaling in the arterial wall.  Am J Cardiol. 1999;  84 21J-24J
• 22 Imai Y, Clemmons DR. Roles of phosphatidylinositol 3-kinase and mitogen- activated protein kinase pathways in stimulation of vascular smooth muscle cell migration and deoxyribonucleic acid synthesis by insulin-like growth factor-I.  Endocrinology. 1999;  140 4228-4235
• 23 Iouzalen L, Stepien O, Marche P. Effects of BAY 10-6734 (Embusartan), a new angiotensin II type I receptor antagonist, on vascular smooth muscle cell growth.  J Pharmacol Exp Ther. 1999;  289 181-187
• 24 Isenovic ER, Jacobs DB, Kedees MH. et al . Angiotensin II regulation of the Na+pump involves the phosphatidylinositol-3 kinase and p42/44 mitogen-activated protein kinase signaling pathways in vascular smooth muscle cells.  Endocrinology. 2004b;  145 1151-1160
• 25 Isenovic ER, Meng Y, Divald A. et al . Role of phosphatidylinositol 3-kinase/Akt pathway in angiotensin II and INS-like growth factor-1 modulation of nitric oxide synthase in vascular smooth muscle cells.  Endocrine. 2002;  19 287-292
• 26 Isenovic ER, Meng Y, Jamali N. et al . Ang II attenuates IGF-1-stimulated Na+, K(+)-ATPase activity via PI3K/Akt pathway in vascular smooth muscle cells.  Int J Mol Med. 2004a;  13 915-922
• 27 Isenoviæ E, Muniyappa R, Milivojeviæ N. et al . Role of PI3-kinase in isoproterenol and IGF-1 induced ecNOS activity.  Biochem Biophys Res Commun. 2001;  285 954-958
• 28 Kauffmann-Zeh A, Rodriguez-Viciana P, Ulrich E. et al . Suppression of c-Myc-induced apoptosis by Ras signalling through PI(3)K and PKB.  Nature. 1997;  385 544-548
• 29 Minden A, Lin A, MacMahon M. et al . Differential activation of ERK and JNK mitogen-activated protein kinases by Raf-1 and MEKK.  Science. 1994;  266 1719-1723
• 30 Montagnani M, Golovchenko I, Kim I. et al . Inhibition of phosphatidylinositol 3-kinase enhances mitogenic actions of INS in endothelial cells.  J Biol Chem. 2002;  277 1794-1799
• 31 Motley ED, Kabir SM, Gardner CD. et al . Lysophosphatidylcholine inhibits insulin-induced Akt activation through protein kinase C-alpha in vascular smooth muscle cells.  Hypertension. 2002;  39 508-512
• 32 Myers Jr MG, Backer JM, Sun XJ. et al . IRS-1 activates phosphatidylinositol 3'-kinase by associating with src homology 2 domains of p85.  Proc Natl Acad Sci USA. 1992;  89 10350-10354
• 33 Natarajan R, Scott S, Bai W. et al . Angiotensin II signaling in vascular smooth musclecells under high glucose conditions.  Hypertension. 1999;  33 378-384
• 34 Nilsson J. Cytokines and smooth muscle cells in atherosclerosis.  Cardiovasc Res. 1993;  27 1184-1190
• 35 Payne DM, Rossomando AJ, Martino P. et al . Identification of the regulatory phosphorylation sites in pp42/mitogen-activated protein kinase (MAP kinase).  EMBO J. 1991;  10 885-892
• 36 Ross R. The pathogenesis of atherosclerosis: a perspective for the 1990 s.  Nature. 1993;  362 801-809
• 37 Sandirasegarane L, Kester M. Enhanced stimulation of Akt-3/protein kinase B-gamma in human aortic smooth muscle cells.  Biochem Biophys Res Commun. 2001;  283 158-163
• 38 Sakuma H, Yamamoto M, Okumura M. et al . High glucose inhibits apoptosis in human coronary artery smooth muscle cells by increasing bcl-xL and bfl-1/A1.  Am J Physiol Cell Physiol. 2002;  283 C422-C428
• 39 Sharma G, Goalstone ML. Regulation of ERK5 by insulin and angiotensin-II in vascular smooth muscle cells.  Biochem Biophys Res Commun. 2007;  354 1078-1083
• 40 Shepherd PR, Nave BT, Rincon J. et al . Involvement of phosphoinositide 3-kinase in INS stimulation of MAP-kinase and phosphorylation of protein kinase-B in human skeletal muscle: implications for glucose metabolism.  Diabetologia. 1997;  40 1172-1177
• 41 Sowers JR, Epstein M. Diabetes mellitus and associated hypertension, vascular disease, and nephropathy. An update.  Hypertension. 1995;  26 869-879
• 42 Stout RW. Insulin and atherogenesis.  Eur J Epidemiol. 1992;  8 134-135
• 43 Taha C, Klip A. The INS signaling pathway.  J Membr Biol. 1999;  169 1-12
• 44 Trovati M, Anfossi G. Influence of insulin and of insulin resistance on platelet and vascular smooth muscle cell function.  J Diabetes Complications. 2002;  16 35-40
• 45 Yin X, Polidano E, Faverdin C. et al . Role of L-type calcium channel blocking in epidermal growth factor receptor-independent activation of extracellular signal regulated kinase 1/2.  J Hypertens. 2005;  23 337-350

Correspondence