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.
References
[1]
Read MA, Boura AL, Walters WA (1993) Vascular actions of purines in the foetal circulation of the human placenta. Br J Pharmacol 110: 454–460.
[2]
Eltzschig HK (2009) Adenosine: an old drug newly discovered. Anesthesiology 111: 904–915.
[3]
Westermeier F, Salomón C, González M, Puebla C, Guzmán-Gutiérrez E, et al. (2011) Insulin restores gestational diabetes mellitus-reduced adenosine transport involving differential expression of insulin receptor isoforms in human umbilical vein endothelium. Diabetes 60: 1677–87.
[4]
Guzmán-Gutiérrez E, Abarzúa F, Belmar C, Nien JK, Ramírez MA, et al. (2011) Functional link between adenosine and insulin: a hypothesis for fetoplacental vascular endothelial dysfunction in gestational diabetes. Curr Vasc Pharmacol 9: 750–762.
[5]
Leiva A, Pardo F, Ramírez MA, Farías M, Casanello P, et al. (2011) Fetoplacental vascular endothelial dysfunction as an early phenomenon in the programming of human adult diseases in subjects born from gestational diabetes mellitus or obesity in pregnancy. Exp Diabetes Res 2011: 349286.
[6]
Vásquez G, Sanhueza F, Vásquez R, González M, San Martín R, et al. (2004) Role of adenosine transport in gestational diabetes-induced L-arginine transport and nitric oxide synthesis in human umbilical vein endothelium. J Physiol 560: 111–122.
[7]
Ciaraldi TP, Morales AJ, Hickman MG, Odom-Ford R, Olefsky JM, et al. (1997) Cellular insulin resistance in adipocytes from obese polycystic ovary syndrome subjects involves adenosine modulation of insulin sensitivity. J Clin Endocrinol Metab 82: 1421–1425.
[8]
Srinivasan M, Herrero P, McGill JB, Bennik J, Heere B, et al. (2005) The effects of plasma insulin and glucose on myocardial blood flow in patients with type 1 diabetes mellitus. J Am Coll Cardiol 46: 42–48.
[9]
González M, Gallardo V, Rodríguez N, Salomón C, Westermeier F, et al. (2011) Insulin-stimulated L-arginine transport requires SLC7A1 gene expression and is associated with human umbilical vein relaxation. J Cell Physiol 226: 2916–2924.
[10]
Mu?oz G, San Martín R, Farías M, Cea L, Vecchiola A, et al. (2006) Insulin restores glucose inhibition of adenosine transport by increasing the expression and activity of the equilibrative nucleoside transporter 2 in human umbilical vein endothelium. J Cell Physiol 209: 826–835.
[11]
da Silva CG, Jarzyna R, Specht A, Kaczmarek E (2006) Extracellular nucleotides and adenosine independently activate AMP-activated protein kinase in endothelial cells: involvement of P2 receptors and adenosine transporters. Circ Res 98: e39–e47.
[12]
Fredholm BB, IJzerman AP, Jacobson KA, Linden J, Müller CE (2011) International Union of Basic and Clinical Pharmacology. LXXXI. Nomenclature and classification of adenosine receptors–an update. Pharmacol Rev 63: 1–34.
[13]
Lappas M, Hiden U, Desoye G, Froehlich J, Hauguel-de Mouzon S, et al. (2011) The role of oxidative stress in the pathophysiology of gestational diabetes mellitus. Antioxid Redox Signal 15: 3061–3100.
[14]
Vásquez R, Farías M, Vega JL, Martin RS, Vecchiola A, et al. (2007) D-glucose stimulation of L-arginine transport and nitric oxide synthesis results from activation of mitogen-activated protein kinases p42/44 and Smad2 requiring functional type II TGF-beta receptors in human umbilical vein endothelium. J Cell Physiol 212: 626–632.
[15]
Casanello P, Sobrevia L (2002) Intrauterine growth retardation is associated with reduced activity and expression of the cationic amino acid transport systems y+/hCAT-1 and y+/hCAT-2B and lower activity of nitric oxide synthase in human umbilical vein endothelial cells. Circ Res 91: 127–134.
[16]
Dong YL, Vegiraju S, Chauhan M, Gangula PR, Hankins GD, et al. (2004) Involvement of calcitonin gene-related peptide in control of human fetoplacental vascular tone. Am J Physiol 286: H230–H239.
[17]
Closs EI, Boissel JP, Habermeier A, Rotmann A (2006) Structure and function of cationic amino acid transporters (CATs). J Membr Biol 213: 67–77.
[18]
Ongini E, Dionisotti S, Gessi S, Irenius E, Fredholm BB (1999) Comparison of CGS 15943, ZM 241385 and SCH 58261 as antagonists at human adenosine receptors. Naunyn Schmiedebergs Arch Pharmacol 359: 7–10.
[19]
Linden J, Thai T, Figler H, Jin X, Robeva AS (1999) Characterization of human A(2B) adenosine receptors: radioligand binding, western blotting, and coupling to G(q) in human embryonic kidney 293 cells and HMC-1 mast cells. Mol Pharmacol 56: 705–713.
[20]
Salvatore CA, Jacobson MA, Taylor HE, Linden J, Johnson RG (1993) Molecular cloning and characterization of the human A3 adenosine receptor. Proc Natl Acad Sci USA 90: 10365–10369.
[21]
Klotz KN, Hessling J, Hegler J, Owman C, Kull B, et al. (1998) Comparative pharmacology of human adenosine receptor subtypes – characterization of stably transfected receptors in CHO cells. Naunyn Schmiedebergs Arch Pharmacol 357: 1–9.
[22]
Guo D, Mulder-Krieger T, Ijzerman AP, Heitman LH (2012) Functional efficacy of adenosine A2A receptor agonists is positively correlated to their receptor residence time. Br J Pharmacol. doi:10.1111/j.1476–5381.2012.01897.x.
[23]
Kenimer JG, Nirenberg M (1981) Desensitization of adenylate cyclase to prostaglandin E1 or 2-chloroadenosine. Mol Pharmacol 20: 585–591.
[24]
Fredholm BB, IJzerman AP, Jacobson KA, Klotz KN, Linden J (2001) International Union of Pharmacology. XXV. Nomenclature and classification of adenosine receptors Pharmacol Rev 53: 527–52.
[25]
Fredholm BB, Lindstr?m K, Dionisotti S, Ongini E (1998) [3H] SCH 58261, a selective adenosine A2A receptor antagonist, is a useful ligand in autoradiographic studies. J Neurochem 70: 1210–6.
[26]
Wyatt AW, Steinert JR, Wheeler-Jones CP, Morgan AJ, Sugden D, et al. (2002) Early activation of the p42/p44MAPK pathway mediates adenosine-induced nitric oxide production in human endothelial cells: a novel calcium-insensitive mechanism. FASEB J 16: 1584–1594.
[27]
Feoktistov I, Goldstein AE, Ryzhov S, Zeng D, Belardinelli L, et al. (2002) Differential expression of adenosine receptors in human endothelial cells: role of A2B receptors in angiogenic factor regulation. Circ Res 90: 531–538.
[28]
Pandolfi A, Di Pietro N (2010) High glucose, nitric oxide, and adenosine: a vicious circle in chronic hyperglycaemia? Cardiovasc Res 86: 9–11.
[29]
Klotz KN, Camaioni E, Volpini R, Kachler S, Vittori S, et al. (1999) 2-Substituted N-ethylcarboxamidoadenosine derivatives as high-affinity agonists at human A3 adenosine receptors. Naunyn Schmiedebergs Arch Pharmacol 360: 103–108.
[30]
Zhang WF, Hu DH, Xu CF, Lü GF, Dong ML, et al. (2010) Inhibitory effect of insulin on nuclear factor-kappa B nuclear translocation of vascular endothelial cells induced by burn serum. Zhonghua Shao Shang Za Zhi 26: 175–179.
[31]
Aljada A, Ghanim H, Saadeh R, Dandona P (2001) Insulin inhibits NF kappaB and MCP-1 expression in human aortic endothelial cells. J Clin Endocrinol Metab 86: 450–453.
[32]
Hammermann R, Brunn G, Racké K (2001) Analysis of the genomic organization of the human cationic amino acid transporters CAT-1, CAT-2 and CAT-4. Amino Acids 21: 211–219.
[33]
Tsai PS, Chen CC, Tsai PS, Yang LC, Huang WY, et al. (2006) Heme oxygenase 1, nuclear factor E2-related factor 2, and nuclear factor kappaB are involved in hemin inhibition of type 2 cationic amino acid transporter expression and L-Arginine transport in stimulated macrophages. Anesthesiology105: 1201–1210.
[34]
Visigalli R, Barilli A, Bussolati O, Sala R, Gazzola GC, et al. (2007) Rapamycin stimulates arginine influx through CAT2 transporters in human endothelial cells. Biochim Biophys Acta 1768: 1479–1487.
[35]
Vega JL, Puebla C, Vásquez R, Farías M, Alarcón J, et al. (2009) TGF-beta1 inhibits expression and activity of hENT1 in a nitric oxide-dependent manner in human umbilical vein endothelium. Cardiovasc Res 82: 458–467.
[36]
Ramkumar V, Jhaveri KA, Xie X, Jajoo S, Toth LA (2011) Nuclear Factor κB and Adenosine Receptors: Biochemical and Behavioral Profiling. Curr Neuropharmacol 9: 342–349.
[37]
Sands WA, Martin AF, Strong EW, Palmer TM (2004) Specific inhibition of nuclear factor-kappaB-dependent inflammatory responses by cell type-specific mechanisms upon A2A adenosine receptor gene transfer. Mol Pharmacol 66: 1147–1159.
[38]
Steinberg HO, Baron AD (2002) Vascular function, insulin resistance and fatty acids. Diabetologia 45: 623–634.
[39]
Escudero C, Casanello P, Sobrevia L (2008) Human equilibrative nucleoside transporters 1 and 2 may be differentially modulated by A2B adenosine receptors in placenta microvascular endothelial cells from pre-eclampsia. Placenta 29: 816–825.
[40]
Espinoza J, Espinoza AF, Power GG (2011) High fetal plasma adenosine concentration: a role for the fetus in preeclampsia? Am J Obstet Gynecol 205: 485.e24–e27.