The identification of adenylyl cyclase modulators as potential receptors for 6-nitrodopamine in human-induced pluripotent stem cell (hiPSC)-derived cardiomyocytes and their relevance in heart inotropism
Irene Cipollone, Vittoria Monaco, José Britto‐Júnior, Antonio Tiago Lima, Edson Antunes, André Sampaio Pupo, Ilaria Iacobucci, Flora Cozzolino, Maria Monti, Silvia Parisi, Giuseppina Divisato, Emanuela Cascone, Alfonso De Simone, Angela Corvino, Ferdinando Fiorino, Francesco Frecentese, Vincenzo Santagada, Beatrice Severino, Rosa Sparaco, Pierfrancesco Cinque, Stefania Vertuccio, Giuseppe Caliendo, Gilberto De Nucci
Abstract
6-Nitrodopamine (6-ND) has potent positive chronotropic and inotropic effects. At a very low dose, i.e., 10 fM, it causes potentiation of the positive chronotropic effects induced by catecholamines in the rat atria, indicating a distinct mechanism of action. Cyclase-associated proteins (CAP-1 and CAP-2) are potential receptors for 6-ND in human cardiomyocytes. Since cyclic 3′,5′-cyclic adenosine monophosphate (cAMP) plays a fundamental role in the positive inotropic effects of classical catecholamines, it was further investigated whether 6-ND potentiates the positive inotropic effects induced by classical catecholamines in the rat isolated perfused heart. Human-induced pluripotent stem cell (hiPSC)-derived cardiomyocytes were harvested and lysed, and following appropriate separation procedures, membrane proteins were incubated with 6-ND-derivatized agarose, centrifuged, and the proteins retained in the agarose eluted with 6-ND (1 mM). The proteins isolated from the chemical pulldown assay were fractionated by SDS-PAGE, the bands were cut and hydrolyzed in situ with trypsin, and then separated and sequenced. A total of 817 proteins were generated, and following screening using UniProt “Retrieve/ID Mapping” function and Gene Ontology cellular component category, 124 proteins were identified as membrane proteins. These experiments identified three proteins that modulate adenylyl cyclase (AC) activity (CAP-1, CAP-2, and STIM1), which are compatible with the pharmacological findings reported for 6-ND in the rat heart. As expected, 6-ND strongly potentiates the inotropic effect induced by noradrenaline in Langendorff’s preparation. In conclusion, 6-ND-induced potentiation of catecholamine-induced chronotropic and inotropic effects is due to the modulation of adenylyl cyclase activity, probably via direct interactions with CAP-1 and CAP-2.