Evaluation of quinazolin-4-piperidine sulfamides as inhibitors of human NPP1 : relevance in the treatment of pathologic mineralization of valve interstitial cells

Le rétrécissement valvulaire aortique calcifié (RAC) est le trouble valvulaire le plus fréquent chez les personnes âgées des pays développés. La seule option de traitement possible le remplacement de la valve aortique. L'identification du rôle de l’enzyme ecto-nucleotidase NPP1 dans le processus de calcification suggère que cette enzyme pourrait être une cible potentielle pour le développement d'un inhibiteur pharmacologique contre la calcification de la valve aortique. Jusqu’à présent, les composés qui ont été développés en tant qu'inhibiteurs de NPP1 manquent de puissance et de spécificité. Dans la présente étude, nous avons démontré que les dérivés de sulfonamides quinazolin-4-pipéridine sont des inhibiteurs puissants, spécifiques, et non-compétitifs de NPP1. In vitro, dans des cellules isolées de valve aortique nous avons fourni des preuves que l’inhibition de NPP1 par ces dérivés bloque la minéralisation, l’apoptose et la transition ostéogénique des cellules interstitielles de valve aortique.Calcific aortic valve disease (CAVD) is the most common valvular disorder in the elderly population in the developed counties with the only valid treatment option today remains the aortic valve repair or replacement. The identification of the role of an ectonucleotidase enzyme NPP1 in the process of calcification shed new light into the development of a pharmacological inhibitor that may prevent the calcification of the aortic valve. By far, the compounds that have been developed as inhibitors of NPP1 lack potency and specificity. In the current study, we showed that the quinazolin-4-piperidin sulfamide derivatives to be a potent, specific, and non-competitive inhibitors of NPP1. We also provided evidence that by inhibiting NPP1 enzyme activity these derivatives are able to prevent phosphate-induced mineralization of valve interstitial cells (VICs), the main cellular component of the aortic valve, by preventing both apoptosis and osteoblastic transitions of VICs

Carbonic anhydrase XII in valve interstitial cells promotes the regression of calcific aortic valve stenosis.

Aims: Calcific aortic valve stenosis (CAVS) is the most common heart valve disease. In the present work we sought to determine the reversibility of mineralization in the aortic valve. Methods and results: By using in vitro analyses we found that valve interstitial cells (VICs) have the ability to resorb minerals. We documented that agonist of P2Y2 receptor (P2Y2R) promoted the expression of carbonic anhydrase XII (CAXII) at the cell membrane of VICs, whereby minerals are resorbed. P2Y2R-mediated mineral resorption was corroborated by using mouse VICs isolated from wild type and P2Y2R-/- mice. Measurements of extracellular pH (pHe) by using core–shell nanosensors revealed that P2Y2R-mediated CAXII export to the cell membrane led to an acidification of extracellular space, whereby minerals are resorbed. In vivo, we next treated LDLR-/-/ApoB100/100/IGF2 mice, which had developed CAVS under a high-fat/high-sucrose diet for 8 months, with 2-thioUTP (a P2Y2R agonist) or saline for the next 2 months. The administration of 2-thioUTP (2 mg/kg/day i.p.) reduced the mineral volume in the aortic valve measured with serial microCT analyses, which improved hemodynamics and reduced left ventricular hypertrophy (LVH). Examination of leaflets at necropsy confirmed a lower level of mineralization and fibrosis along with higher levels of CAXII in mice under 2-thioUTP. In another series of experiment, the administration of acetazolamide (a CA inhibitor) prevented the acidification of leaflets and the regression of CAVS induced by 2-thioUTP in LDLR-/-/ApoB100/100/IGF2 mice. Conclusion: P2Y2R-mediated expression of CAXII by VICs acidifies the extracellular space and promotes the regression of CAVS