A769662 inhibits insulin-stimulated Akt activation in human macrovascular endothelial cells independent of AMP-activated protein kinase

Strembitska, A., Mancini, S. J., Gamwell, J. M., Palmer, T. M., Baillie, G. S. and Salt, I. P. (2018) A769662 inhibits insulin-stimulated Akt activation in human macrovascular endothelial cells independent of AMP-activated protein kinase. International Journal of Molecular Sciences, 19(12), 3886. (doi:10.3390/ijms19123886) (PMID:30563079) (PMCID:PMC6321332)

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Abstract

Protein kinase B (Akt) is a key enzyme in the insulin signalling cascade, required for insulin-stimulated NO production in endothelial cells (ECs). Previous studies have suggested that AMP-activated protein kinase (AMPK) activation stimulates NO synthesis and enhances insulin-stimulated Akt activation, yet these studies have largely used indirect activators of AMPK. The effects of the allosteric AMPK activator A769662 on insulin signalling and endothelial function was therefore examined in cultured human macrovascular ECs. Surprisingly, A769662 inhibited insulin-stimulated NO synthesis and Akt phosphorylation in human ECs from umbilical veins (HUVECs) and aorta (HAECs). In contrast, the AMPK activators compound 991 and AICAR had no substantial inhibitory effect on insulin-stimulated Akt phosphorylation in ECs. Inhibition of AMPK with SBI-0206965 had no effect on the inhibition of insulin-stimulated Akt phosphorylation by A769662, suggesting the inhibitory action of A769662 is AMPK-independent. A769662 decreased IGF1-stimulated Akt phosphorylation yet had no effect on VEGF-stimulated Akt signalling in HUVECs, suggesting that A769662 attenuates early insulin/IGF1 signalling. The effects of A769662 on insulin-stimulated Akt phosphorylation were specific to human ECs, as no effect was observed in the human cancer cell lines HepG2 or HeLa, as well as in mouse embryonic fibroblasts (MEFs). A769662 inhibited insulin-stimulated Erk1/2 phosphorylation in HAECs and MEFs, an effect that was independent of AMPK in MEFs. Therefore, despite being a potent AMPK activator, A769662 has effects unlikely to be mediated by AMPK in human macrovascular ECs that reduce insulin sensitivity and eNOS activation.

Item Type:Articles
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:Mancini, Dr Sarah and Strembitska, Anastasiya and Salt, Dr Ian and Baillie, Professor George and Palmer, Dr Tim
Authors: Strembitska, A., Mancini, S. J., Gamwell, J. M., Palmer, T. M., Baillie, G. S., and Salt, I. P.
College/School:College of Medical Veterinary and Life Sciences > Institute of Cardiovascular and Medical Sciences
College of Medical Veterinary and Life Sciences > Institute of Molecular Cell and Systems Biology
Journal Name:International Journal of Molecular Sciences
Publisher:MDPI
ISSN:1661-6596
ISSN (Online):1422-0067
Copyright Holders:Copyright © 2018 The Authors
First Published:First published in International Journal of Molecular Sciences 19(12):3886
Publisher Policy:Reproduced under a Creative Commons License

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Project CodeAward NoProject NamePrincipal InvestigatorFunder's NameFunder RefLead Dept
684311BHF 4 Year PhD Studentship AwardRhian TouyzBritish Heart Foundation (BHF)FS/14/61/31284RI CARDIOVASCULAR & MEDICAL SCIENCES
641891Inhibition of endothelial mitogen-activated protein kinases by amp-activated protein kinaseIan SaltBritish Heart Foundation (BHF)PG/13/82/30483RI CARDIOVASCULAR & MEDICAL SCIENCES
580311The sensitive assessment of the activity of cellular signalling pathways regulating insulin action and the cardiovascular complications of diabetesIan SaltDiabetes UK (DIABETUK)11/0004309RI CARDIOVASCULAR & MEDICAL SCIENCES

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