Pressure Overload–Mediated Sustained PKR2 (Prokineticin-2 Receptor) Signaling in Cardiomyocytes Contributes to Cardiac Hypertrophy and Endotheliopathies

Abstract

Chronic cardiac pressure overload, caused by conditions, such as hypertension, induces pathological hypertrophic growth of myocardium and vascular rarefaction, with largely unknown mechanisms. Here, we described that expression of the PKR2 (prokineticin-2 receptor) is increased in the cardiomyocytes of mice following transaortic constriction pressure overload–mediated pathological hypertrophy. To identify PKR2-induced pathways, we performed microarray analysis on TG-PKR2 (transgenic mice overexpressing cardiomyocyte-restricted human PKR2) hearts and cytokine analyses in hPKR2 overexpressing H9c2-lines (PKR2-cardiomyocytes). An enrichment of activin pathway gene sets was found in both TG-PKR2 and transaortic constriction-operated hearts. Elevated levels of 2 cytokines activin A and its coreceptor, sENG (soluble Endoglin), were found in both PKR2-cardiomyocytes and in PKR2-cardiomyocytes conditioned medium. ELISA analyses of the cardiomyocytes derived from both TG-PKR2 and transaortic constriction hearts revealed high levels of these cardiokines that were repressed with antibodies blocking PKR2, indicating a PKR2-dependent event. The conditioned medium of PKR2-cardiomyocytes induced fenestration of endothelial cells and inhibited tube-like formations. These endotheliopathies were blocked by either depleting activin A or sENG from conditioned medium or by using 2 pharmacological inhibitors, follistatin, and TRC105. In addition, similar endotheliopathies were produced by exogenous administration of activin A and ENG. Prolonged exposure to prokineticin-2 in PKR2-cardiomyocytes increased cell volume by the PKR2/Gα 12/13 /ERK5-pathway. Activation of the PKR2/Gα 12/13 /matrix metalloprotease-pathway promoted both activin A and sENG release. This study reveals that pressure overload–mediated PKR2 signaling in cardiomyocytes contributes to cardiac hypertrophy through autocrine signaling, and vascular rarefaction via cardiac cytokine-mediated cardiomyocyte–endothelial cell communications. Our results may contribute to the development of potential therapeutic targets for heart failure.