Role of RyR2 phosphorylation at S2814 during heart failure progression

Area of Science:

• Cardiovascular Biology
• Molecular Cardiology
• Heart Failure Pathophysiology

Background:

• Increased Ca(2+)/calmodulin-dependent protein kinase II (CaMKII) activity is implicated in heart failure (HF) progression.
• The specific role of CaMKII-mediated ryanodine receptor type 2 (RyR2) phosphorylation in HF and diastolic Ca(2+) leak remains unclear.

Purpose of the Study:

• To investigate the function of CaMKII phosphorylation of RyR2 in both human and murine models of nonischemic and ischemic heart failure.
• To elucidate the contribution of RyR2 phosphorylation to cardiac dysfunction and sarcoplasmic reticulum Ca(2+) handling in HF.

Main Methods:

• Analysis of RyR2 S2814 phosphorylation in human HF patients and wild-type versus S2814A knock-in mice.
• Induction of transverse aortic constriction (TAC) and experimental myocardial infarction (MI) in mice.
• Assessment of cardiac function, pulmonary congestion, atrial natriuretic factor levels, and cardiomyocyte Ca(2+) leak and loading.

Main Results:

• Elevated RyR2 S2814 phosphorylation was observed in nonischemic HF patients but not ischemic HF.
• S2814A mice showed protection against TAC-induced HF, with reduced congestion and preserved cardiac function.
• S2814A cardiomyocytes exhibited decreased sarcoplasmic reticulum Ca(2+) leak and improved Ca(2+) loading post-TAC.
• Protective effects were absent in S2814A mice following experimental myocardial infarction.

Conclusions:

• CaMKII-dependent RyR2 phosphorylation at S2814 is a key contributor to pathological Ca(2+) leak in nonischemic heart failure.
• Targeting RyR2 phosphorylation may offer a therapeutic strategy for specific forms of HF, such as those induced by pressure overload.