Abstract 16338: Dna Hypomethylation in Long Non-coding Rna Promoter During Calcific Aortic Valve Stenosis: Implication for the Notch Pathway
Introduction:Calcific aortic valve stenosis (CAVS) is the most common valvular heart disease. Transdifferentiation of valve interstitial cells of the aortic valve (VICs) into osteogenic cells is an important process in the pathology. However, the molecular mechanisms involved in gene expression during osteogenic transition are still poorly understood.
Hypothesis:Long non-coding RNAs (lncRNAs) regulate gene expression pattern and may be involved in the osteogenic transdifferentiation during the development of the CAVS.
Methods:Transcriptomic by RNA sequencing (RNA-seq) and DNA genome-wide methylation studies were performed in human aortic valves. In addition, the role of a lncRNA on the mineralization was explored and the molecular mechanisms by which it promotes osteogenic transdifferentiation was documented.
Results:Transcriptomic profiling of CAVS and control valves revealed that a lncRNA was highly expressed in mineralized valves. The CpG islands in the promoter region of the gene coding this lncRNA were hypomethylated (n=23). These data were confirmed by q-PCR (n=152), fluorescence in situ hybridization (FISH) and pyrosequencing (n=60). Methylation status of the lncRNA promoter was inversely related to expression level and in isolated VICs a treatment with 5-aza-2’-deoxycytidine, which causes DNA demethylation, increased the expression of lncRNA by 2,5-fold. Knockdown or overexpression experiments showed that lncRNA play an important role in the osteogenic transdifferentiation via the Notch1 pathway. Promoter studies coupled with luciferase and chromatin immunoprecipitation (ChIP) revealed that this lncRNA interferes with the activity of Notch1 by physically interacting with the promoter. LncRNA-induced mineralization of VICs was rescued by a co-transfection of a vector encoding for the Notch intracellular domain (NICD).
Conclusions:During CAVS the hypomethylation in the promoter region promotes the overexpression of a lncRNA. This lncRNA promotes the dysfunction of the Notch signaling pathway and induces the osteogenic transdifferentiation of VICs.
Author Disclosures: F. Hadji: None. M. Boulanger: None. É. Lavoie-Charland: None. N. Gaudreault: None. S. Guauque-Olarte: None. R. Bouchareb: None. M. Nsaibia: None. L. Bouchard: None. Y. Bossé: None. P. Mathieu: None.
- © 2015 by American Heart Association, Inc.