Contractile responses to endothelin-1 are regulated by PKC phosphorylation of cardiac myosin binding protein-C in rat ventricular myocytes. (April 2018)

• Record Type: Journal Article
• Authors: Smyrnias, Ioannis; Goodwin, Normann; Wachten, Dagmar; Skogestad, Jonas; Aronsen, Jan Magnus; Robinson, Emma L.; Demydenko, Kateryna; Segonds-Pichon, Anne; Oxley, David; Sadayappan, Sakthivel; Sipido, Karin; Bootman, Martin D.; Roderick, H. Llewelyn
• Is Part Of: Journal of molecular and cellular cardiology. Volume 117(2018)
• Page Start: 1
• Page End: 18
• Publication Date: 2018-04
• Subjects: ECC Excitation-Contraction Coupling -- CICR Ca2+-induced Ca2+ release -- ET-1 Endothelin-1 -- SR Sarcoplasmic Reticulum -- SERCA SR/ER Ca2+ ATPase -- NCX Na+/Ca2+ exchanger -- NHE Na+/H+ exchanger -- InsP3(R) Inositol 1, 4, 5-trisphosphate (receptor) -- PLC Phospholipase C -- DAG Diacylglycerol -- DN-PKCε Dominant-Negative PKCε -- ETA/ETB Endothelin receptor subtype (A or B) -- ARVMs Adult Rat Ventricular Myocytes -- FCR Fractional Ca2+ Release -- 5′Phos Adenoviral-mediated expression of the type 1 InsP3 5′phosphatase -- Chel Chelerythrine -- BimI/V Bisindolylmaleimide I/V -- Iso Isoproterenol -- cMyBP-C Cardiac Myosin Binding Protein-C; Endothelin -- PKC -- InsP3 -- ECC -- Cardiac myocyte; Cardiology -- Periodicals; Heart Diseases -- Periodicals; Molecular Biology -- Periodicals; Cardiologie -- Périodiques; Cardiology; Electronic journals; Periodicals; 616.12
• DOI: 10.1016/j.yjmcc.2018.02.012
• Languages: English
• ISSNs: 0022-2828

Abstract

Abstract: The shortening of sarcomeres that co-ordinates the pump function of the heart is stimulated by electrically-mediated increases in [Ca 2+ ]. This process of excitation-contraction coupling (ECC) is subject to modulation by neurohormonal mediators that tune the output of the heart to meet the needs of the organism. Endothelin-1 (ET-1) is a potent modulator of cardiac function with effects on contraction amplitude, chronotropy and automaticity. The actions of ET-1 are evident during normal adaptive physiological responses and increased under pathophysiological conditions, such as following myocardial infarction and during heart failure, where ET-1 levels are elevated. In myocytes, ET-1 acts through ETA - or ETB -G protein-coupled receptors (GPCRs). Although well studied in atrial myocytes, the influence and mechanisms of action of ET-1 upon ECC in ventricular myocytes are not fully resolved. We show in rat ventricular myocytes that ET-1 elicits a biphasic effect on fractional shortening (initial transient negative and sustained positive inotropy) and increases the peak amplitude of systolic Ca 2+ transients in adult rat ventricular myocytes. The negative inotropic phase was ETB receptor-dependent, whereas the positive inotropic response and increase in peak amplitude of systolic Ca 2+ transients required ETA receptor engagement. Both effects of ET-1 required phospholipase C (PLC)-activity, although distinct signalling pathways downstream of PLC elicited the effects of each ET receptor. The negative inotropic response involved inositol 1, 4, 5-trisphosphate (InsP3 ) signalling and protein kinase C epsilon (PKCε). The positive inotropic action and the enhancement in Ca 2+ transient amplitude induced by ET-1 were independent of InsP3 signalling, but suppressed by PKCε. Serine 302 in cardiac myosin binding protein-C was identified as a PKCε substrate that when phosphorylated contributed to the suppression of contraction and Ca 2+ transients by PKCε following ET-1 stimulation. Thus, our data provide a new role and mechanism of action for InsP3 and PKCε in mediating the negative inotropic response and in restraining the positive inotropy and enhancement in Ca 2+ transients following ET-1 stimulation. Graphical abstract: Unlabelled Image Highlights: ET-1 elicits biphasic effects on contraction and Ca 2+ transients in rat ventricular myocytes. The initial negative inotropy is ETB receptor dependent and the subsequent increase in contraction is via ETA receptors. InsP3 -mediated Ca 2+ release contributes to the altered kinetics but not amplitude of Ca 2+ transients elicited by ET-1. PKCε restricts ET-1 stimulated increases in contractility and amplitude of systolic Ca 2+ transients. PKC elicits its effects on contraction through phosphorylation of cMyBP-C on S302.