Insulin-increased L-arginine transport requires A2A adenosine receptors activation in human umbilical vein endothelium

Guzman-Gutierrez, Enrique, Westermeier, Francisco, Salomon, Carlos, Gonzalez, Marcelo, Pardo, Fabian, Leiva, Andrea and Sobrevia, Luis (2012) Insulin-increased L-arginine transport requires A2A adenosine receptors activation in human umbilical vein endothelium. PLoS ONE, 7 7: e41705.1-e41705.13. doi:10.1371/journal.pone.0041705


Author Guzman-Gutierrez, Enrique
Westermeier, Francisco
Salomon, Carlos
Gonzalez, Marcelo
Pardo, Fabian
Leiva, Andrea
Sobrevia, Luis
Title Insulin-increased L-arginine transport requires A2A adenosine receptors activation in human umbilical vein endothelium
Formatted title
Insulin-increased L-arginine transport requires A2A adenosine receptors activation in human umbilical vein endothelium
Journal name PLoS ONE   Check publisher's open access policy
ISSN 1932-6203
Publication date 2012-07-23
Year available 2012
Sub-type Article (original research)
DOI 10.1371/journal.pone.0041705
Open Access Status DOI
Volume 7
Issue 7
Start page e41705.1
End page e41705.13
Total pages 13
Place of publication San Francisco United States
Publisher Public Library of Science (PLoS)
Language eng
Formatted abstract
Adenosine causes vasodilation of human placenta vasculature by increasing the transport of arginine via cationic amino acid transporters 1 (hCAT-1). This process involves the activation of A2A adenosine receptors (A2AAR) in human umbilical vein endothelial cells (HUVECs). Insulin increases hCAT-1 activity and expression in HUVECs, and A2AAR stimulation increases insulin sensitivity in subjects with insulin resistance. However, whether A2AAR plays a role in insulin-mediated increase in L-arginine transport in HUVECs is unknown. To determine this, we first assayed the kinetics of saturable L-arginine transport (1 minute, 37°C) in the absence or presence of nitrobenzylthioinosine (NBTI, 10 μmol/L, adenosine transport inhibitor) and/or adenosine receptors agonist/antagonists. We also determined hCAT-1 protein and mRNA expression levels (Western blots and quantitative PCR), and SLC7A1 (for hCAT-1) reporter promoter activity. Insulin and NBTI increased the extracellular adenosine concentration, the maximal velocity for L-arginine transport without altering the apparent Km for L-arginine transport, hCAT-1 protein and mRNA expression levels, and SLC7A1 transcriptional activity. An A2AAR antagonist ZM-241385 blocked these effects. ZM241385 inhibited SLC7A1 reporter transcriptional activity to the same extent in cells transfected with pGL3-hCAT-1-1606 or pGL3-hCAT-1-650 constructs in the presence of NBTI + insulin. However, SLC7A1 reporter activity was increased by NBTI only in cells transfected with pGL3-hCAT-1-1606, and the ZM-241385 sensitive fraction of the NBTI response was similar in the absence or in the presence of insulin. Thus, insulin modulation of hCAT-1 expression and activity requires functional A2AAR in HUVECs, a mechanism that may be applicable to diseases associated with fetal insulin resistance, such as gestational diabetes.
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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