Antioxidants & redox signaling · 2013
HNO enhances SERCA2a activity and cardiomyocyte function by promoting redox-dependent phospholamban oligomerization.
СтатьяПоддержка NIH: внешняя программаПоддержка исследования: вне правительства СШАПоддержка правительства СШАНазвание и аннотация: Перевод в очереди
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Sivakumaran Vidhya, Stanley Brian A, Tocchetti Carlo G, Ballin Jeff D, Caceres Viviane, Zhou Lufang, Keceli Gizem, Rainer Peter P, Lee Dong I, Huke Sabine, Ziolo Mark T, Kranias Evangelia G, Toscano John P, Wilson Gerald M, O'Rourke Brian, Kass David A, Mahaney James E, Paolocci Nazareno
Аннотация
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 Ca(2+) 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 Ca(2+) transient, and blunted β-adrenergic responsiveness. HNO stimulated shortening, relaxation, and Ca(2+) transient in WT cardiomyocytes, and evoked positive inotropy/lusitropy in intact hearts. These changes were markedly blunted in pln(-/-) cells/hearts. HNO enhanced SR Ca(2+) uptake in WT but not pln(-/-) SR-vesicles. Spectroscopic studies in insect cell microsomes expressing SERCA2a±PLN showed that HNO increased Ca(2+)-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 Ca(2+) handling in failing 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 Ca(2+) transient, and blunted β-adrenergic responsiveness. HNO stimulated shortening, relaxation, and Ca(2+) transient in WT cardiomyocytes, and evoked positive inotropy/lusitropy in intact hearts. These changes were markedly blunted in pln(-/-) cells/hearts. HNO enhanced SR Ca(2+) uptake in WT but not pln(-/-) SR-vesicles. Spectroscopic studies in insect cell microsomes expressing SERCA2a±PLN showed that HNO increased Ca(2+)-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 Ca(2+) handling in failing hearts.
Предметные рубрики MeSH
Adenosine TriphosphateAnimalsAntioxidantsCalciumCalcium SignalingCalcium-Binding ProteinsCardiotonic AgentsCyclic AMP-Dependent Protein KinasesDisulfidesHeart VentriclesIn Vitro TechniquesMiceMice, KnockoutMicrosomesMyocytes, CardiacNitrogen OxidesOxidation-ReductionPhosphorylationProtein BindingProtein ConformationProtein Interaction Domains and MotifsProtein MultimerizationProtein StabilitySarcoplasmic ReticulumSarcoplasmic Reticulum Calcium-Transporting ATPasesPhospholamban