Spironolactone prevents L-type Ca V 1.2 potentiation and chronic vasoconstriction during diabetic hyperglycemia.

Vascular complications are major causes of morbidity and mortality in diabetic patients. Recently, our group identified a novel purinergic signaling pathway involving the P2Y /AKAP5/AC5/PKA/Ca 1.2 protein network in arterial myocytes. This purinergic complex is activated by the release of nucleotides (e.g. ATP) to the extracellular space in response to hyperglycemic conditions, which promotes L-type Ca 1.2 potentiation and vasoconstriction. Pannexin 1 (Panx1) is a channel that mediates ATP efflux, thus inducing purinergic signaling activation. However, whether Panx1 forms part of the novel purinergic signaling complex that regulates L-type Ca 1.2 activity and vascular reactivity during diabetic hyperglycemia is unknown. Here, we find that Panx1 is in complex with P2Y , AKAP5, AC5, PKA and Ca 1.2 in arterial myocytes. This protein complex is strengthened upon elevated glucose (HG) treatment. However, the Panx1 inhibitor spironolactone prevented the HG-induced strengthening of the complex. Spironolactone also blocked cAMP production, L-type Ca 1.2 potentiation and sustained vasoconstriction in response to elevated glucose. Consistent with a role for Panx1 upstream of P2Y , spironolactone failed to prevent HG-induced vasoconstriction upon addition of the specific P2Y agonist NF546. Altogether, these data suggest that Panx1 is part of the P2Y /AKAP5/AC5/PKA/Ca 1.2 signaling module in arterial myocytes. This Panx1-led complex modulates L-type Ca 1.2 activity and vascular reactivity in response to diabetic hyperglycemic conditions. Thus, Panx1 could be a new therapeutic target to treat vascular complications during diabetes.