title: Adenosine derived from ecto-nucleotidases in calcific aortic valve disease promotes mineralization through A2a adenosine receptor.
abstract: OBJECTIVE
  In this study, we sought to determine the role of ecto-nucleotidases and adenosine receptors in calcific aortic valve disease (CAVD). The expression of ecto-nucleotidases, which modify the levels of extracellular nucleotides/nucleosides, may control the mineralization of valve interstitial cells (VICs). We hypothesized that expression of ectonucleotide pyrophosphatase/phosphodiesterase 1 (NPP1), which generates AMP, and 5'-nucleotidase (CD73), an enzyme using AMP as a substrate to produce adenosine, may co-regulate the mineralization of the aortic valve.
  
  
  RESULTS
  We have investigated the expression of NPP1 and 5'-nucleotidase in CAVD tissues and determined the role of these ecto-nucleotidases on the mineralization of isolated VICs. In CAVD tissues (stenotic and sclerotic), we documented that NPP1 and 5'-nucleotidase were overexpressed by VICs. In isolated VICs, we found that mineralization induced by adenosine triphosphate was decreased by silencing NPP1 and 5'-nucleotidase, suggesting a role for adenosine. Adenosine and specific A2a adenosine receptor (A2aR) agonist increased the mineralization of VICs. Silencing of A2aR in human VICs and the use of A2aR(-/-) mouse VICs confirmed that A2aR promotes the mineralization of cells. Also, A2aR-mediated mineralization was negated by the transfection of a mutant dominant-negative Gαs vector. Through several lines of evidence, we next documented that adenosine stimulated the mineralization of VICs through a cAMP/protein kinase A (PKA)/cAMP response element-binding protein (CREB) pathway, and found that CREB positively regulated the expression of NPP1 in a positive feedback loop by physically interacting with the promoter.
  
  
  CONCLUSIONS
  Expression of NPP1 and 5'-nucleotidase by VICs promotes the mineralization of the aortic valve through A2aR and a cAMP/PKA/CREB pathway.
authors: Laboratoire d'Études Moléculaires des Valvulopathies (LEMV), Groupe de Recherche en Valvulopathies (GRV), Quebec Heart and Lung Institute/Research Center, Department of Surgery, Laval University, 2725 Chemin Ste-Foy, Quebec, Canada G1V-4G5.
authors: Ablajan
authors: A
authors: Mahmut
authors: Laboratoire d'Études Moléculaires des Valvulopathies (LEMV), Groupe de Recherche en Valvulopathies (GRV), Quebec Heart and Lung Institute/Research Center, Department of Surgery, Laval University, 2725 Chemin Ste-Foy, Quebec, Canada G1V-4G5.
authors: Marie-Chloé
authors: MC
authors: Boulanger
authors: Laboratoire d'Études Moléculaires des Valvulopathies (LEMV), Groupe de Recherche en Valvulopathies (GRV), Quebec Heart and Lung Institute/Research Center, Department of Surgery, Laval University, 2725 Chemin Ste-Foy, Quebec, Canada G1V-4G5.
authors: Rihab
authors: R
authors: Bouchareb
authors: Laboratoire d'Études Moléculaires des Valvulopathies (LEMV), Groupe de Recherche en Valvulopathies (GRV), Quebec Heart and Lung Institute/Research Center, Department of Surgery, Laval University, 2725 Chemin Ste-Foy, Quebec, Canada G1V-4G5.
authors: Fayez
authors: F
authors: Hadji
authors: Laboratoire d'Études Moléculaires des Valvulopathies (LEMV), Groupe de Recherche en Valvulopathies (GRV), Quebec Heart and Lung Institute/Research Center, Department of Surgery, Laval University, 2725 Chemin Ste-Foy, Quebec, Canada G1V-4G5 patrick.mathieu@chg.ulaval.ca.
authors: Patrick
authors: P
authors: Mathieu
mesh_terms: D015720:5'-Nucleotidase / Q000502:physiology; D000241:Adenosine / Q000502:physiology*; D000251:Adenosine Triphosphatases / Q000502:physiology*; D000368:Aged; D000818:Animals; D001021:Aortic Valve / Q000473:pathology* / Q000503:physiopathology*; D001024:Aortic Valve Stenosis / Q000503:physiopathology*; D000082882:Bicuspid Aortic Valve Disease; D002114:Calcinosis / Q000503:physiopathology*; D000242:Cyclic AMP / Q000502:physiology; D017362:Cyclic AMP Response Element-Binding Protein / Q000502:physiology; D017868:Cyclic AMP-Dependent Protein Kinases / Q000502:physiology; D004195:Disease Models, Animal; D005260:Female; D006330:Heart Defects, Congenital / Q000503:physiopathology*; D006349:Heart Valve Diseases / Q000503:physiopathology*; D006801:Humans; D008297:Male; D051379:Mice; D018345:Mice, Knockout; D008875:Middle Aged; D010727:Phosphoric Diester Hydrolases / Q000502:physiology; D011755:Pyrophosphatases / Q000502:physiology; D043705:Receptor, Adenosine A2A / Q000172:deficiency / Q000235:genetics / Q000502:physiology*; D015398:Signal Transduction / Q000502:physiology
chemical_list: D017362:Cyclic AMP Response Element-Binding Protein; D043705:Receptor, Adenosine A2A; D000242:Cyclic AMP; D017868:Cyclic AMP-Dependent Protein Kinases; D015720:5'-Nucleotidase; D010727:Phosphoric Diester Hydrolases; C065962:ectonucleotide pyrophosphatase phosphodiesterase 1; D000251:Adenosine Triphosphatases; D011755:Pyrophosphatases; C027201:ectoATPase; D000241:Adenosine
keywords: 5′-nucleotidase; A2a receptor; Adenosine; Aortic stenosis; Biomineralization; CD73; CREB; Calcific aortic valve disease; Calcific aortic valve stenosis; ENPP1; Ectopic mineralization; NPP1; NT5E; PKA