Insulin rapidly stimulates l-arginine transport in human aortic endothelial cells via Akt
| Autor: | Vrushali Patil, Christine F. Kohlhaas, Valerie A. Morrow, John M. C. Connell, Ian P. Salt, Neelam Jhakra, John R. Petrie |
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| Jazyk: | angličtina |
| Předmět: |
Arginine
Ad.Akt-DN adenovirus expressing dominant negative mutant Akt Hsp90 heat shock protein 90 030204 cardiovascular system & hematology Biochemistry 0302 clinical medicine HUVEC human umbilical vein endothelial cell Insulin BAEC bovine aortic endothelial cell Aorta 0303 health sciences Nitric Oxide Synthase Type III eNOS endothelial nitric oxide synthase Cell biology medicine.anatomical_structure Phosphorylation Ad.control control adenovirus PMA phorbol 12-myristate 13-acetate medicine.medical_specialty PI3 K phosphatidylinositol 3’kinase Endothelium Biophysics Transport Biology HAEC human aortic endothelial cell Article Cell Line 03 medical and health sciences Internal medicine PKC protein kinase C medicine Humans Molecular Biology Protein kinase B Protein kinase C 030304 developmental biology NO nitric oxide Biological Transport Nitric oxide Cell Biology Transport inhibitor Endocrinology Cell culture MARCKS myristoylated alanine-rich protein kinase C substrate Endothelium Vascular Proto-Oncogene Proteins c-akt Ad.Akt-CA adenovirus expressing constitutively active mutant Akt |
| Zdroj: | Biochemical and Biophysical Research Communications |
| ISSN: | 0006-291X |
| DOI: | 10.1016/j.bbrc.2011.08.048 |
| Popis: | Highlights ► Regulation of NO synthesis by l-arginine transport in endothelial cells. ► L-arginine transport stimulated by insulin and high glucose. ► Insulin-stimulated l-arginine transport dependent on Akt activation. ► Culture glucose concentrations have no effect on l-arginine transporter levels. Insulin stimulates endothelial NO synthesis, at least in part mediated by phosphorylation and activation of endothelial NO synthase at Ser1177 and Ser615 by Akt. We have previously demonstrated that insulin-stimulated NO synthesis is inhibited under high culture glucose conditions, without altering Ca2+-stimulated NO synthesis or insulin-stimulated phosphorylation of eNOS. This indicates that stimulation of endothelial NO synthase phosphorylation may be required, yet not sufficient, for insulin-stimulated nitric oxide synthesis. In the current study we investigated the role of supply of the eNOS substrate, l-arginine as a candidate parallel mechanism underlying insulin-stimulated NO synthesis in cultured human aortic endothelial cells. Insulin rapidly stimulated l-arginine transport, an effect abrogated by incubation with inhibitors of phosphatidylinositol-3′-kinase or infection with adenoviruses expressing a dominant negative mutant Akt. Furthermore, supplementation of endothelial cells with extracellular l-arginine enhanced insulin-stimulated NO synthesis, an effect reversed by co-incubation with the l-arginine transport inhibitor, l-lysine. Basal l-arginine transport was significantly increased under high glucose culture conditions, yet insulin-stimulated l-arginine transport remained unaltered. The increase in l-arginine transport elicited by high glucose was independent of the expression of the cationic amino acid transporters, hCAT1 and hCAT2 and not associated with any changes in the activity of ERK1/2, Akt or protein kinase C (PKC). We propose that rapid stimulation of L-arginine transport contributes to insulin-stimulated NO synthesis in human endothelial cells, yet attenuation of this is unlikely to underlie the inhibition of insulin-stimulated NO synthesis under high glucose conditions. |
| Databáze: | OpenAIRE |
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