Abstract 16761: Long Non-coding RNA Meg3 Controls Endothelial Cell Function: Implications for Endothelial Aging and Senescence (Best of Basic Science Abstract)
The majority of transcribed RNA does not encode proteins, but may function as regulatory RNA. Long non-coding RNAs (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 Meg3 (35.3±0.6 RPKM), which was increased in replicative senescent HUVECs in vitro (passage 16/17 vs 2/3, 2.9±0.99-fold). Interestingly, Meg3 is induced in the intima of aged mice and correlates with age in human hearts (p=0.016). In HUVECs, Meg3 localizes to the nucleus and is also induced by hypoxia (4.08±0.78-fold, p<0.05). Silencing of Meg3 using LNA-GapmeRs induced angiogenic sprouting and proliferation of endothelial cells in vitro (1.4±0.14-fold, P<0.05) and repressed SA-β-galactosidase activity. Conversely, lentiviral overexpression of Meg3 inhibited sprouting angiogenesis and cell cycle progression, although splicing isoforms of Meg3 show differential effects.
Mechanistically, RNA immunoprecipitation showed that Meg3 associates specifically to H3K27me3, a silencing chromatin mark, and interacts with EZH2, a histone methyl transferase. Silencing of Meg3 in HUVECs represses, and overexpression of Meg3 induces, global gene expression, as measured by exon array analysis. As Meg3 was described to recruit Jarid2 to chromatin, we determined whether Meg3 requires Jarid2. The Meg3 loss-of-function induced repression of proliferation was normalized after silencing Jarid2, indicating that Meg3 effects are at least partly Jarid2-dependent. Finally, silencing of Meg3 in aged mice in vivo using gapmeRs in combination with hind limb ischemia significantly repressed Meg3 levels in the hindlimb and induced recovery of perfusion compared to control mice. Capillary and arteriole density was also markedly induced after silencing Meg3.
These results demonstrate that silencing 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: Consultant/Advisory Board; Modest; Miragen. Research Grant; Significant; ERC, DFG.
- © 2015 by American Heart Association, Inc.