Abstract 18412: Long Non-coding RNA Meg3 Regulates Senescence-associated Genes and Controls Endothelial Cell Function
The majority of transcribed RNAs does not encode proteins, but function as regulatory RNAs. Non-protein-coding RNA are classified in short (<200 nt) and long (>200 nt) non-coding RNAs (lncRNAs). lncRNAs have been described to play an important role in many biological processes, including epigenetic regulation of gene expression.
To determine the expression and functional role of lncRNAs in endothelial cells, we performed RNA deep sequencing of human umbilical venous endothelial cells (ECs). Among the highest expressed lncRNAs, we identified Maternally Expressed 3 (Meg3, 35.3±0.6 RPKM), which has been correlated to VEGF expression. In HUVECs, Meg3 localizes to the nucleus and is induced by hypoxia (4.08±0.78-fold, p<0.05). Interestingly, Meg3 was also found to be induced in the intima of aged mice and correlates with age in human hearts (p=0.016). Meg3 levels are also induced in replicative senescent HUVECs in vitro (passage 16/17 vs 2/3, 2.9±0.99-fold).Conversely, silencing of Meg3 using LNA-GapmeRs induced angiogenic sprouting of endothelial cells in vitro (1.4±0.14-fold, P<0.05) but did not affect caspase-3 activation. Mechanistically, RNA immunoprecipations showed that Meg3 associates specifically to H3K27me3, a silencing chromatin mark. Silencing of Meg3 in HUVECs induces a robust repression of global gene expression, as measured by exon array analysis, with a highly significant repression of the anti-senescent HMGA2.
In summary these results demonstrate, that the lncRNA Meg3 is highly expressed in endothelial cells and is up-regulated by hypoxia and aging. Functionally, Meg3 inhibits sprouting angiogenesis in vitro. Meg3 depletion leads to a general repression of gene expression and the senescence marker HMGA2 likely by inducing the recruitment of silencing H3K27me3 marks to the promoters Therefore, modulating Meg3 may be a potential strategy to reduce endothelial senescence or increase regenerative angiogenesis.
Author Disclosures: R. Boon: None. P. Hofmann: None. K. Michalik: None. A. Knau: None. Y. Ponomareva: None. A. Zeiher: None. S. Uchida: None. S. Dimmeler: None.
- © 2014 by American Heart Association, Inc.