Oxidized Ca2+/Calmodulin-Dependent Protein Kinase II Triggers Atrial Fibrillation

A Purohit, AG Rokita, X Guan, B Chen, OM Koval… - Circulation, 2013 - Am Heart Assoc
A Purohit, AG Rokita, X Guan, B Chen, OM Koval, N Voigt, S Neef, T Sowa, Z Gao…
Circulation, 2013Am Heart Assoc
Background—Atrial fibrillation (AF) is a growing public health problem without adequate
therapies. Angiotensin II and reactive oxygen species are validated risk factors for AF in
patients, but the molecular pathways connecting reactive oxygen species and AF are
unknown. The Ca2+/calmodulin-dependent protein kinase II (CaMKII) has recently emerged
as a reactive oxygen species–activated proarrhythmic signal, so we hypothesized that
oxidized CaMKIIδ could contribute to AF. Methods and Results—We found that oxidized …
Background
Atrial fibrillation (AF) is a growing public health problem without adequate therapies. Angiotensin II and reactive oxygen species are validated risk factors for AF in patients, but the molecular pathways connecting reactive oxygen species and AF are unknown. The Ca2+/calmodulin-dependent protein kinase II (CaMKII) has recently emerged as a reactive oxygen species–activated proarrhythmic signal, so we hypothesized that oxidized CaMKIIδ could contribute to AF.
Methods and Results
We found that oxidized CaMKII was increased in atria from AF patients compared with patients in sinus rhythm and from mice infused with angiotensin II compared with mice infused with saline. Angiotensin II–treated mice had increased susceptibility to AF compared with saline-treated wild-type mice, establishing angiotensin II as a risk factor for AF in mice. Knock-in mice lacking critical oxidation sites in CaMKIIδ (MM-VV) and mice with myocardium-restricted transgenic overexpression of methionine sulfoxide reductase A, an enzyme that reduces oxidized CaMKII, were resistant to AF induction after angiotensin II infusion.
Conclusions
Our studies suggest that CaMKII is a molecular signal that couples increased reactive oxygen species with AF and that therapeutic strategies to decrease oxidized CaMKII may prevent or reduce AF.
Am Heart Assoc