Adiponectin inhibits insulin-like growth factor-1-induced cell migration by the suppression of extracellular signal-regulated kinase 1/2 activation, but not Akt in vascular smooth muscle cells.
Adiponectin, an adipocyte-derived hormone, has been proposed to show antiatherogenic properties through the inhibitory effects against various growth factors. Insulin-like growth factor-1 (IGF-1) is one of the potent mitogens, which has been considered to play important roles in both atherogenesis and plaque stabilization in accordance to the phase of atherosclerosis. The aim of this study is to elucidate the adiponectin effects on IGF-1-induced cell migration and its intracellular signaling pathways in vascular smooth muscle cells (VSMCs). In this study, we assessed cell migration and several kinase activities in cultured rat aortic smooth muscle cells (RASMCs). Adiponectin pretreatment suppressed IGF-1-induced cell migration and extracellular signal-regulated kinase (ERK)1/2 activation, which is one of the major mediators for IGF-1-induced cell migration. In RASMCs, adiponectin and 5-aminoimidazole-4-carboxamide riboside (AICAR), a 5'-AMP-activated protein kinase (AMPK) activator, stimulated AMPK activation. AMPK activation by AICAR inhibited IGF-1-induced ERK1/2 activation and cell migration in RASMCs. On the other hand, phosphorylation of Akt and Bad, proapoptotic molecules of the Bcl-2 family, which were increased by IGF-1 stimulation, was not diminished by the pretreatment with adiponectin. It was shown that adiponectin inhibited IGF-1-induced VSMC migration through suppression of ERK1/2 activation, which might be implicated in AMPK activation. Furthermore, adiponectin selectively inhibited ERK1/2 pathway, not Akt-Bad pathway, stimulated by IGF-1. From these findings, it was implied that adiponectin suppressed IGF-1-induced VSMC migration and its signaling selectivity.
Motobayashi
Yuki
Y
Department of Pharmacology, The Institute of Health Bioscience, The University of Tokushima Graduate School, Tokushima, Japan.
Izawa-Ishizawa
Yuki
Y
Ishizawa
Keisuke
K
Orino
Sakiko
S
Yamaguchi
Kunihisa
K
Kawazoe
Kazuyoshi
K
Hamano
Shuichi
S
Tsuchiya
Koichiro
K
Tomita
Shuhei
S
Tamaki
Toshiaki
T
D052242:Adiponectin / Q000494:pharmacology*; D000620:Aminoimidazole Carboxamide / Q000031:analogs & derivatives / Q000494:pharmacology; D000818:Animals; D015153:Blotting, Western; D002465:Cell Movement / Q000187:drug effects*; D004789:Enzyme Activation / Q000187:drug effects; D020536:Enzyme Activators / Q000494:pharmacology; D007334:Insulin-Like Growth Factor I / Q000037:antagonists & inhibitors* / Q000494:pharmacology; D008297:Male; D019950:Mitogen-Activated Protein Kinase 1 / Q000378:metabolism / Q000502:physiology*; D048052:Mitogen-Activated Protein Kinase 3 / Q000378:metabolism / Q000502:physiology*; D032389:Myocytes, Smooth Muscle / Q000187:drug effects / Q000378:metabolism*; D051058:Oncogene Protein v-akt / Q000502:physiology*; D010766:Phosphorylation / Q000187:drug effects; D051381:Rats; D017207:Rats, Sprague-Dawley; D012265:Ribonucleotides / Q000494:pharmacology; D015398:Signal Transduction / Q000187:drug effects; D051025:bcl-Associated Death Protein / Q000378:metabolism; D048051:p38 Mitogen-Activated Protein Kinases / Q000378:metabolism
D052242:Adiponectin; D020536:Enzyme Activators; D012265:Ribonucleotides; D051025:bcl-Associated Death Protein; D000620:Aminoimidazole Carboxamide; D007334:Insulin-Like Growth Factor I; D051058:Oncogene Protein v-akt; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D048051:p38 Mitogen-Activated Protein Kinases; C031143:AICA ribonucleotide