Involvement of the Dual-Specificity Tyrosine Phosphorylation-Regulated Kinase 1A-Alternative Splicing Factor Calcium/Calmodulin-Dependent Protein Kinase 118 Signaling Pathway in Myocardial Infarction-Induced Heart Failure of Rats

Background: Alternative splicing factor (ASF) regulated alternative splicing of calcium/calmodulin-dependent protein kinase II delta (CaMKII delta) plays an important role in pathologic cardiac remodeling. ASF can be phosphorylated by dual-specificity tyrosine phosphorylation-regulated kinase 1A (Dyrk1A). This study aimed to investigate the possible involvement of the Dyrk1A-ASF-CaMICII delta signaling pathway in the progression of myocardial infarction (ME)-induced heart failure (HF). Methods and Results: MI in rats was induced by means of left anterior descending coronary artery ligation. Seven weeks after MI, the increase in left ventricular internal diameter at end-diastole (LVIDd), and the decrease in both ejection fraction (EF) and fractional shortening (FS) indicated that MI rats had developed HF. Quantitative real time reverse-transcription polymerase chain reaction indicated the dysregulation of CaMICII delta alternative splicing, ie, up-regulation of CaMKII delta A and CaMKII delta C and down-regulation of CaMKII delta B in the hearts of HF rats. Electrophoresis and immunostaining revealed that HF activated the phosphorylation of ASF and affected its subcellular localization. Western blot analysis demonstrated a significant elevation in the activity and expression of Dyrk1A in HF rats. Inversely, treatment of MI-induCed HF rats with Dyrk1A inhibitor, either harmine or EGCG, improved the symptoms of HF, reversed the molecular changes of Dyrk1A and ASF, and regulated alternative splicing of CaMKII delta in HF rats. Conclusions: Enhanced activation of Dyrk1A-ASF-CaMICII delta signaling pathway may underlie the mechanisms of BY after MI, and Dyrk1A inhibition may contribute to inactivation of this pathway and thereby retard the progression of MI-induced HF.