title: Epigenetic balance of aberrant Rasal1 promoter methylation and hydroxymethylation regulates cardiac fibrosis.
abstract: OBJECTIVE
  Methylation of CpG island promoters is a prototypical epigenetic mechanism to stably control gene expression. The aim of this study was to elucidate the contribution of aberrant promoter DNA methylation in pathological endothelial to mesenchymal transition (EndMT) and subsequent cardiac fibrosis.
  
  
  RESULTS
  In human coronary endothelial cells, TGFβ1 causes aberrant methylation of RASAL1 promoter, increased Ras-GTP activity, and EndMT. In end-stage failing vs. non-failing human myocardium, increased fibrosis was associated with significantly increased RASAL1 promoter methylation, decreased RASAL1 expression, increased Ras-GTP activity, and increased expression of markers of EndMT. In mice with pressure overload due to ascending aortic constriction, BMP7 significantly reduced RASAL1 promoter methylation, increased RASAL1 expression, and decreased EndMT markers as well as decreased cardiac fibrosis. The ten eleven translocation (TET) family enzyme TET3, which demethylates through hydroxymethylation, was significantly decreased in fibrotic mouse hearts, restored with BMP7, and BMP7 effects were absent in coronary endothelial cells with siRNA knockdown of TET3.
  
  
  CONCLUSIONS
  Our study provides proof-in-principle evidence that transcriptional suppression of RASAL1 through aberrant promoter methylation contributes to EndMT and ultimately to progression of cardiac fibrosis. Such aberrant methylation can be reversed through Tet3-mediated hydroxymethylation, which can be specifically induced by BMP7. This may reflect a new treatment strategy to stop cardiac fibrosis.
authors.affiliation: Department of Cardiology and Pneumology, University Medical Center of Göttingen, Georg-August University, Robert-Koch-Str. 40, 37075 Göttingen, Germany.
authors.forename: Xingbo
authors.initials: X
authors.lastname: Xu
authors.affiliation: Department of Cardiology and Pneumology, University Medical Center of Göttingen, Georg-August University, Robert-Koch-Str. 40, 37075 Göttingen, Germany.
authors.forename: Xiaoying
authors.initials: X
authors.lastname: Tan
authors.affiliation: Department of Nephrology and Rheumatology, University Medical Center of Göttingen, Georg-August University, Göttingen, Germany.
authors.forename: Björn
authors.initials: B
authors.lastname: Tampe
authors.affiliation: Department of Nephrology and Rheumatology, University Medical Center of Göttingen, Georg-August University, Göttingen, Germany.
authors.forename: Gunsmaa
authors.initials: G
authors.lastname: Nyamsuren
authors.affiliation: Department of Cardiology and Pneumology, University Medical Center of Göttingen, Georg-August University, Robert-Koch-Str. 40, 37075 Göttingen, Germany.
authors.forename: Xiaopeng
authors.initials: X
authors.lastname: Liu
authors.affiliation: Department of Internal Medicine II, University of Regensburg, Regensburg, Germany.
authors.forename: Lars S
authors.initials: LS
authors.lastname: Maier
authors.affiliation: Department of Cardiology and Pneumology, University Medical Center of Göttingen, Georg-August University, Robert-Koch-Str. 40, 37075 Göttingen, Germany.
authors.forename: Samuel
authors.initials: S
authors.lastname: Sossalla
authors.affiliation: Department of Cancer Biology and the Metastasis Research Center, University of Texas MD Anderson Cancer Center, Houston, TX, USA.
authors.forename: Raghu
authors.initials: R
authors.lastname: Kalluri
authors.affiliation: Department of Nephrology and Rheumatology, University Medical Center of Göttingen, Georg-August University, Göttingen, Germany.
authors.forename: Michael
authors.initials: M
authors.lastname: Zeisberg
authors.affiliation: Department of Cardiology and Pneumology, University Medical Center of Göttingen, Georg-August University, Robert-Koch-Str. 40, 37075 Göttingen, Germany German Center for Cardiovascular Research (DZHK), Partner Site Göttingen, Göttingen, Germany.
authors.forename: Gerd
authors.initials: G
authors.lastname: Hasenfuss
authors.affiliation: Department of Cardiology and Pneumology, University Medical Center of Göttingen, Georg-August University, Robert-Koch-Str. 40, 37075 Göttingen, Germany German Center for Cardiovascular Research (DZHK), Partner Site Göttingen, Göttingen, Germany Elisabeth.Zeisberg@med.uni-goettingen.de.
authors.forename: Elisabeth M
authors.initials: EM
authors.lastname: Zeisberg
mesh_terms: D000818:Animals; D055419:Bone Morphogenetic Protein 7 / Q000494:pharmacology; D009202:Cardiomyopathies / Q000235:genetics* / Q000378:metabolism / Q000473:pathology / Q000503:physiopathology / Q000517:prevention & control; D002352:Carrier Proteins / Q000235:genetics* / Q000378:metabolism; D016022:Case-Control Studies; D002460:Cell Line; D018899:CpG Islands; D019175:DNA Methylation; D004268:DNA-Binding Proteins / Q000378:metabolism; D049308:Dioxygenases / Q000378:metabolism; D004195:Disease Models, Animal; D018450:Disease Progression; D042783:Endothelial Cells / Q000378:metabolism / Q000473:pathology; D044127:Epigenesis, Genetic; D058750:Epithelial-Mesenchymal Transition; D005355:Fibrosis; D020690:GTPase-Activating Proteins / Q000235:genetics* / Q000378:metabolism; D005786:Gene Expression Regulation; D006333:Heart Failure / Q000235:genetics* / Q000378:metabolism / Q000473:pathology / Q000503:physiopathology / Q000517:prevention & control; D006801:Humans; D051379:Mice; D032383:Myocytes, Cardiac / Q000187:drug effects / Q000378:metabolism* / Q000473:pathology; D011401:Promoter Regions, Genetic; D011518:Proto-Oncogene Proteins / Q000378:metabolism; D034622:RNA Interference; D015398:Signal Transduction; D013997:Time Factors; D014158:Transcription, Genetic; D014162:Transfection; D018631:ras Proteins / Q000378:metabolism
chemical_list: D055419:Bone Morphogenetic Protein 7; D002352:Carrier Proteins; D004268:DNA-Binding Proteins; D020690:GTPase-Activating Proteins; D011518:Proto-Oncogene Proteins; C580923:RASAL1 protein, human; C576391:RASAL2 protein, human; C578792:TET3 protein, human; D049308:Dioxygenases; C551915:Tet3 protein, mouse; D018631:ras Proteins
keywords: Cardiac fibrosis; Endothelial to mesenchymal transition; Hydroxymethylation; Methylation; Rasal1; Tet3