TNF-alpha decreased SERCA2a expression by increasing DNA methyltransferase levels and enhancing methylation in the SERCA2a promoter region in HL-1 cardiomyocytes.
Does TNF-alpha decrease SERCA2a expression via promoter methylation in HL-1 cardiomyocytes?
TNF-alpha decreases SERCA2a expression in cardiomyocytes by increasing DNA methyltransferase levels and enhancing promoter methylation, suggesting hypermethylation inhibition as a potential therapeutic target for cardiac dysfunction.
OBJECTIVES: Sarcoplasmic reticulum Ca-ATPases (SERCA2a) plays an essential role in the Ca homeostasis and cardiac functions. Tumor necrosis factor-alpha (TNF-alpha) decreases the SERCA2a, which may underlie cardiac dysfunction during sepsis and heart failure. Because the promoter region of SERCA2a contains CpG islands, gene methylation should be critical in regulating SERCA2a. The present study was to evaluate whether TNF-alpha can modulate SERCA2a via enhancing methylation and to investigate the underlying mechanisms. DESIGN: Controlled laboratory experiment. SETTING: University research laboratory. SUBJECTS: HL-1 cardiomyocytes. INTERVENTIONS: TNF-alpha (1-50 ng/mL) was administered in HL-1 cardiomyocytes with and without co-administration of an NF-kappaB inhibitor (SN-50, 50 microg/mL), antioxidant agents (ascorbic acid, 100 microM, or coenzyme Q10, 10 microM), or methylation inhibitor (5-aza-2'-deoxycytidine, 0.1, 1 microM). MEASUREMENTS AND MAIN RESULTS: TNF-alpha (50 ng/mL) decreased the SERCA2a RNA and protein by quantitative polymerase chain reaction and immunoblot. Furthermore, TNF-alpha (50 ng/mL) increased the methylation in the SERCA2a promoter region, which was not influenced by the co-administration of SN-50, ascorbic acid, or coenzyme Q10, but was attenuated by 5-aza-2'-deoxycytidine (0.1 microM). Additionally, TNF-alpha (50 ng/mL) increased the expression of DNA methyltransferase 1. CONCLUSIONS: TNF-alpha increased DNA methyltransferase levels, thus enhancing the methylation in the SERCA2a promoter region with a result of reducing SERCA2a. These findings suggest that inhibition of hypermethylation may be a novel treatment strategy for cardiac dysfunction.
Kao et al. (Thu,) conducted a other in Cardiac dysfunction. TNF-alpha vs. Without TNF-alpha or with co-administration of inhibitors was evaluated on SERCA2a RNA and protein expression, and methylation in the SERCA2a promoter region. TNF-alpha decreased SERCA2a expression by increasing DNA methyltransferase levels and enhancing methylation in the SERCA2a promoter region in HL-1 cardiomyocytes.