title: Tumor necrosis factor-alpha decreases sarcoplasmic reticulum Ca2+-ATPase expressions via the promoter methylation in cardiomyocytes.
abstract: OBJECTIVE
  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.
  
  
  METHODS
  Controlled laboratory experiment.
  
  
  METHODS
  University research laboratory.
  
  
  METHODS
  HL-1 cardiomyocytes.
  
  
  METHODS
  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).
  
  
  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.
authors.affiliation: Graduate Institute of Clinical Medicine, Taipei Medical University, Taipei, Taiwan.
authors.forename: Yu-Hsun
authors.initials: YH
authors.lastname: Kao
authors.forename: Yao-Chang
authors.initials: YC
authors.lastname: Chen
authors.forename: Chen-Chuan
authors.initials: CC
authors.lastname: Cheng
authors.forename: Ting-I
authors.initials: TI
authors.lastname: Lee
authors.forename: Yi-Jen
authors.initials: YJ
authors.lastname: Chen
authors.forename: Shih-Ann
authors.initials: SA
authors.lastname: Chen
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000187:drug effects / Q000235:genetics; D015152:Blotting, Northern; D002118:Calcium / Q000378:metabolism*; D002478:Cells, Cultured; D019175:DNA Methylation; D005786:Gene Expression Regulation; D006325:Heart Atria / Q000166:cytology; D051379:Mice; D032383:Myocytes, Cardiac / Q000378:metabolism*; D018384:Oxidative Stress / Q000187:drug effects; D011401:Promoter Regions, Genetic; D012313:RNA / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D053498:Sarcoplasmic Reticulum Calcium-Transporting ATPases / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*; D012680:Sensitivity and Specificity; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology*
chemical_list: D014409:Tumor Necrosis Factor-alpha; D012313:RNA; D053498:Sarcoplasmic Reticulum Calcium-Transporting ATPases; D002118:Calcium