Role of glycogen synthase kinase3β/GATA-4 in tumor necrosis factor-α-regulated sarcoplasmic recticulum Ca²⁺-ATPase expressions in cardiomyocytes

Background: Sarcoplasmic reticulum Ca²⁺-ATPaSe (SERCA2a) plays an essential role in Ca²⁺ homeostasis and cardiac functions. Tumor necrosis factor-α (TNF-α) decreases the SERCA2a, which can induce cardiac dysfunction. GATA-4 is a critical transcription factor in load-mediated SERCA2a expression and negatively regulated by glycogen synthase kinase3β (GSK3β). The present study was to evaluate whether TNF-α can modulate SERCA2a via GSK3β and GATA-4. Methods: To determine whether TNF-α could modulate the expression of SERCA2a, GSK3β, and GATA-4, HL-1 cells were treated with TNF-α (50 ng/ml) for 24 hours. The expressions of SERCA2a, GSK3β and nuclear GATA-4 were measured by real-time RT-PCR and immunoblot analysis. Results: TNF-α decreased the RNA expression of SERCA2a by 30 ± 8%. In contrast, the protein level of GSK3β was not significantly changed by TNF-α. In addition, TNF-α did not alter the protein expression of nuclear GATA-4. Conclusion: TNF-α decreases SERCA2a expression. These findings suggest that GSK3β and GATA-4 may not play an important role in SERCA2a modulation during acute inflammatory stage.