Effects of 4(1H)-quinolinone derivative, a novel non-nucleotide allosteric purinergic P2Y agonist, on cardiomyocytes in neonatal rats.

Purinergic P2Y receptors, G-protein coupled receptors that primarily couple with Gα-proteins, are activated equipotently by adenosine-5'-triphosphate (ATP) and uridine-5'-triphosphate. Evidence suggests that P2Y agonists make potential drug candidates for the treatment of cardiovascular diseases. However, selective non-nucleotide, small-molecule P2Y agonists have yet to be developed. In this report, we discuss Compound 89, a novel non-nucleotide allosteric P2Y agonist that was active in signal transduction and gene induction, and in our in vitro cardiac hypertrophy model. Compound 89 exhibited selective P2Y agonistic activity and potentiated responses to the endogenous agonist ATP, while exhibiting no agonistic activities for four other Gα-coupled human P2Y (hP2Y) receptors and one representative Gα-coupled hP2Y receptor. Its P2Y agonistic effect on mouse P2Y receptors suggested non-species-specific activity. Compound 89 acted as a pure positive allosteric modulator in a Ca mobilization assay of neonatal rat cardiomyocytes; it potentiated ATP-induced expression of genes in the nuclear receptor 4A family (negative regulators of hypertrophic stimuli in cardiomyocytes). Additionally, Compound 89 attenuated isoproterenol-induced cardiac hypertrophy, presumably through dose-dependent interaction with pericellular ATP. These results indicate that Compound 89 is potentially efficacious against cardiomyocytes and therefore a good proof-of-concept tool for elucidating the therapeutic potential of P2Y activation in various cardiovascular diseases.