TY - JOUR
T1 - HNO Enhances SERCA2a activity and cardiomyocyte function by promoting redox-dependent phospholamban oligomerization
AU - Sivakumaran, Vidhya
AU - Stanley, Brian A.
AU - Tocchetti, Carlo G.
AU - Ballin, Jeff D.
AU - Caceres, Viviane
AU - Zhou, Lufang
AU - Keceli, Gizem
AU - Rainer, Peter P.
AU - Lee, Dong I.
AU - Huke, Sabine
AU - Ziolo, Mark T.
AU - Kranias, Evangelia G.
AU - Toscano, John P.
AU - Wilson, Gerald M.
AU - O'Rourke, Brian
AU - Kass, David A.
AU - Mahaney, James E.
AU - Paolocci, Nazareno
PY - 2013/10/10
Y1 - 2013/10/10
N2 - Aims: Nitroxyl (HNO) interacts with thiols to act as a redox-sensitive modulator of protein function. It enhances sarcoplasmic reticular Ca 2+ uptake and myofilament Ca2+ sensitivity, improving cardiac contractility. This activity has led to clinical testing of HNO donors for heart failure. Here we tested whether HNO alters the inhibitory interaction between phospholamban (PLN) and the sarcoplasmic reticulum Ca 2+-ATPase (SERCA2a) in a redox-dependent manner, improving Ca 2+ handling in isolated myocytes/hearts. Results: Ventriculocytes, sarcoplasmic reticulum (SR) vesicles, and whole hearts were isolated from control (wildtype [WT]) or PLN knockout (pln-/-) mice. Compared to WT, pln-/- myocytes displayed enhanced resting sarcomere shortening, peak Ca2+ transient, and blunted β-adrenergic responsiveness. HNO stimulated shortening, relaxation, and Ca2+ transient in WT cardiomyocytes, and evoked positive inotropy/lusitropy in intact hearts. These changes were markedly blunted in pln-/- cells/hearts. HNO enhanced SR Ca2+ uptake in WT but not pln-/- SR-vesicles. Spectroscopic studies in insect cell microsomes expressing SERCA2a±PLN showed that HNO increased Ca2+-dependent SERCA2a conformational flexibility but only when PLN was present. In cardiomyocytes, HNO achieved this effect by stabilizing PLN in an oligomeric disulfide bond-dependent configuration, decreasing the amount of free inhibitory monomeric PLN available. Innovation: HNO-dependent redox changes in myocyte PLN oligomerization relieve PLN inhibition of SERCA2a. Conclusions: PLN plays a central role in HNO-induced enhancement of SERCA2a activity, leading to increased inotropy/lusitropy in intact myocytes and hearts. PLN remains physically associated with SERCA2a; however, less monomeric PLN is available resulting in decreased inhibition of the enzyme. These findings offer new avenues to improve Ca2+ handling in failing hearts. Antioxid. Redox Signal. 19, 1185-1197.
AB - Aims: Nitroxyl (HNO) interacts with thiols to act as a redox-sensitive modulator of protein function. It enhances sarcoplasmic reticular Ca 2+ uptake and myofilament Ca2+ sensitivity, improving cardiac contractility. This activity has led to clinical testing of HNO donors for heart failure. Here we tested whether HNO alters the inhibitory interaction between phospholamban (PLN) and the sarcoplasmic reticulum Ca 2+-ATPase (SERCA2a) in a redox-dependent manner, improving Ca 2+ handling in isolated myocytes/hearts. Results: Ventriculocytes, sarcoplasmic reticulum (SR) vesicles, and whole hearts were isolated from control (wildtype [WT]) or PLN knockout (pln-/-) mice. Compared to WT, pln-/- myocytes displayed enhanced resting sarcomere shortening, peak Ca2+ transient, and blunted β-adrenergic responsiveness. HNO stimulated shortening, relaxation, and Ca2+ transient in WT cardiomyocytes, and evoked positive inotropy/lusitropy in intact hearts. These changes were markedly blunted in pln-/- cells/hearts. HNO enhanced SR Ca2+ uptake in WT but not pln-/- SR-vesicles. Spectroscopic studies in insect cell microsomes expressing SERCA2a±PLN showed that HNO increased Ca2+-dependent SERCA2a conformational flexibility but only when PLN was present. In cardiomyocytes, HNO achieved this effect by stabilizing PLN in an oligomeric disulfide bond-dependent configuration, decreasing the amount of free inhibitory monomeric PLN available. Innovation: HNO-dependent redox changes in myocyte PLN oligomerization relieve PLN inhibition of SERCA2a. Conclusions: PLN plays a central role in HNO-induced enhancement of SERCA2a activity, leading to increased inotropy/lusitropy in intact myocytes and hearts. PLN remains physically associated with SERCA2a; however, less monomeric PLN is available resulting in decreased inhibition of the enzyme. These findings offer new avenues to improve Ca2+ handling in failing hearts. Antioxid. Redox Signal. 19, 1185-1197.
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U2 - 10.1089/ars.2012.5057
DO - 10.1089/ars.2012.5057
M3 - Article
C2 - 23919584
AN - SCOPUS:84884776664
SN - 1523-0864
VL - 19
SP - 1185
EP - 1197
JO - Antioxidants and Redox Signaling
JF - Antioxidants and Redox Signaling
IS - 11
ER -