Insulin-stimulated L-arginine transport requires SLC7A1 gene expression and is associated with human umbilical vein relaxation

Gonzalez, Marcelo, Gallardo, Victoria, Rodriguez, Natalia, Salomon, Carlos, Westermeier, Francisco, Guzman-Gutierrez, Enrique, Abarzua, Fernando, Leiva, Andrea, Casanello, Paola and Sobrevia, Luis (2011) Insulin-stimulated L-arginine transport requires SLC7A1 gene expression and is associated with human umbilical vein relaxation. Journal of Cellular Physiology, 226 11: 2916-2924. doi:10.1002/jcp.22635


Author Gonzalez, Marcelo
Gallardo, Victoria
Rodriguez, Natalia
Salomon, Carlos
Westermeier, Francisco
Guzman-Gutierrez, Enrique
Abarzua, Fernando
Leiva, Andrea
Casanello, Paola
Sobrevia, Luis
Title Insulin-stimulated L-arginine transport requires SLC7A1 gene expression and is associated with human umbilical vein relaxation
Journal name Journal of Cellular Physiology   Check publisher's open access policy
ISSN 0021-9541
1097-4652
Publication date 2011
Sub-type Article (original research)
DOI 10.1002/jcp.22635
Open Access Status
Volume 226
Issue 11
Start page 2916
End page 2924
Total pages 9
Place of publication Hoboken, NJ, United States
Publisher John Wiley & Sons
Language eng
Abstract Insulin causes endothelium-derived nitric oxide (NO)-dependent vascular relaxation, and increases L-arginine transport via cationic amino acid transporter 1 (hCAT-1) and endothelial NO synthase (eNOS) expression and activity in human umbilical vein endothelium (HUVEC). We studied insulin effect on SLC7A1 gene (hCAT-1) expression and hCAT-transport activity role in insulin-modulated human fetal vascular reactivity. HUVEC were used for L-arginine transport and L-[ 3H]citrulline formation (NOS activity) assays in absence or presence of N-ethylmaleimide (NEM) or L-lysine (L-arginine transport inhibitors). hCAT-1 protein abundance was estimated by Western blot, mRNA quantification by real time PCR, and SLC7A1 promoter activity by Luciferase activity (-1,606 and -650bp promoter fragments from ATG). Specific protein 1 (Sp1), and total or phosphorylated eNOS protein was determined by Western blot. Sp1 activity (at four sites between -177 and -105bp from ATG) was assayed by chromatin immunoprecipitation (ChIP) and vascular reactivity in umbilical vein rings. Insulin increased hCATs-L-arginine transport, maximal transport capacity (V max/K m), and hCAT-1 expression. NEM and L-lysine blocked L-arginine transport. In addition, it was trans-stimulated (~7.8-fold) by L-lysine in absence of insulin, but unaltered (~1.4-fold) in presence of insulin. Sp1 nuclear protein abundance and binding to DNA, and SLC7A1 promoter activity was increased by insulin. Insulin increased NO synthesis and caused endothelium-dependent vessel relaxation and reduced U46619-induced contraction, effects blocked by NEM and L-lysine, and dependent on extracellular L-arginine. We suggest that insulin induces human umbilical vein relaxation by increasing HUVEC L-arginine transport via hCATs (likely hCAT-1) most likely requiring Sp1-activated SLC7A1 expression.
Q-Index Code C1
Q-Index Status Provisional Code
Institutional Status Non-UQ

Document type: Journal Article
Sub-type: Article (original research)
Collection: UQ Centre for Clinical Research Publications
 
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