PMID- 16506055
OWN - NLM
STAT- MEDLINE
DCOM- 20061024
LR  - 20181113
IS  - 0012-186X (Print)
IS  - 0012-186X (Linking)
VI  - 49
IP  - 5
DP  - 2006 May
TI  - Insulin activates hypoxia-inducible factor-1alpha in human and rat vascular 
      smooth muscle cells via phosphatidylinositol-3 kinase and mitogen-activated 
      protein kinase pathways: impairment in insulin resistance owing to defects in 
      insulin signalling.
PG  - 1049-63
AB  - AIMS/HYPOTHESIS: We previously demonstrated that insulin stimulates vascular 
      endothelial growth factor (VEGF) synthesis and secretion via 
      phosphatidylinositol-3 kinase (PI3-K) and mitogen-activated protein kinase (MAPK) 
      pathways in vascular smooth muscle cells (VSMC) from humans and from 
      insulin-sensitive lean Zucker fa/+ rats. We also showed that this effect is 
      attenuated in VSMC from insulin-resistant obese Zucker fa/fa rats. As it is not 
      known whether the effects of insulin on VEGF involve activation of 
      hypoxia-inducible factor-1 (HIF-1), we aimed to evaluate: (1) whether insulin 
      modulates HIF-1alpha protein synthesis and activity; (2) the insulin signalling 
      pathways involved; and (3) the role of insulin resistance. METHODS: Using aortic 
      VSMC taken from humans and Zucker rats and cultured in normoxia, the following 
      were evaluated: (1) dose-dependent (0.5, 1, 2 nmol/l) and time-dependent (2, 4, 6 
      h) effects exerted by insulin on HIF-1alpha content in both nucleus and cytosol, 
      measured by Western blots; (2) insulin effects on HIF-1 DNA-binding activity on 
      the VEGF gene, measured by electrophoretic mobility shift assay; and (3) 
      involvement of the insulin signalling molecules in these insulin actions, by 
      using the following inhibitors: LY294002 (PI3-K), PD98059 (extracellular signal 
      regulated kinase [ERK]), SP600125 (Jun N terminal kinase [JNK]), SB203580 (p38 
      mitogen-activated protein kinase) and rapamycin (mammalian target of rapamycin), 
      and by detecting the insulin signalling molecules by Western blots. RESULTS: In 
      aortic VSMC from humans and Zucker fa/+ rats cultured in normoxia insulin 
      increases the HIF-1alpha content in cytosol and nucleus via dose- and 
      time-dependent mechanisms, and HIF-1 DNA-binding activity on the VEGF gene. The 
      insulin-induced increase of HIF-1alpha is blunted by the translation inhibitor 
      cycloheximide, LY294002, PD98059, SP600125 and rapamycin, but not by SB203580. It 
      is also reduced in Zucker fa/fa rats, which present an impaired ability of 
      insulin to induce Akt, ERK-1/2 and JNK-1/2 phosphorylation. 
      CONCLUSIONS/INTERPRETATION: These results provide a biological mechanism for the 
      impaired collateral vessel formation in obesity.
FAU - Doronzo, G
AU  - Doronzo G
AD  - Diabetes Unit, Department of Clinical and Biological Sciences, University of 
      Turin, San Luigi Gonzaga Hospital, I-10043, Orbassano, Turin, Italy.
FAU - Russo, I
AU  - Russo I
FAU - Mattiello, L
AU  - Mattiello L
FAU - Riganti, C
AU  - Riganti C
FAU - Anfossi, G
AU  - Anfossi G
FAU - Trovati, M
AU  - Trovati M
LA  - eng
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
DEP - 20060228
PL  - Germany
TA  - Diabetologia
JT  - Diabetologia
JID - 0006777
RN  - 0 (Enzyme Inhibitors)
RN  - 0 (HIF1A protein, human)
RN  - 0 (Hypoxia-Inducible Factor 1, alpha Subunit)
RN  - 0 (Imidazoles)
RN  - 0 (Insulin)
RN  - 0 (Pyridines)
RN  - EC 2.7.1.- (Phosphatidylinositol 3-Kinases)
RN  - EC 2.7.11.24 (Mitogen-Activated Protein Kinases)
RN  - OU13V1EYWQ (SB 203580)
SB  - IM
MH  - Animals
MH  - Enzyme Inhibitors/pharmacology
MH  - Humans
MH  - Hypoxia-Inducible Factor 1, alpha Subunit/*metabolism
MH  - Imidazoles/pharmacology
MH  - Insulin/*pharmacology/*physiology
MH  - Insulin Resistance/*physiology
MH  - Kinetics
MH  - Mitogen-Activated Protein Kinases/*metabolism
MH  - Muscle, Smooth, Vascular/drug effects/*physiology
MH  - Phosphatidylinositol 3-Kinases/*metabolism
MH  - Pyridines/pharmacology
MH  - Rats
MH  - Rats, Zucker
MH  - Signal Transduction/physiology
EDAT- 2006/03/01 09:00
MHDA- 2006/10/25 09:00
CRDT- 2006/03/01 09:00
PHST- 2005/07/25 00:00 [received]
PHST- 2005/11/17 00:00 [accepted]
PHST- 2006/03/01 09:00 [pubmed]
PHST- 2006/10/25 09:00 [medline]
PHST- 2006/03/01 09:00 [entrez]
AID - 10.1007/s00125-006-0156-0 [doi]
PST - ppublish
SO  - Diabetologia. 2006 May;49(5):1049-63. doi: 10.1007/s00125-006-0156-0. Epub 2006 
      Feb 28.