Abstract 16718: The Long Noncoding RNA H19 Controls Vascular Ageing and Inflammation
Long noncoding RNAs (lncRNAs) are endogenously expressed noncoding RNAs with a length of more than 200 nucleotides, which can regulate gene expression through various mechanisms. Laminar shear stress and the expression of the flow-induced transcription factor Krüppel like factor 2 (KLF2) decrease with ageing. We hypothesize that protective factors like shear stress and detrimental factors like ageing and inflammation regulate the expression of lncRNAs that in turn regulate endothelial cell (EC) functions.
Using next generation sequencing, we identified differentially regulated lncRNAs in several tissues of young and aged mice. The most profoundly regulated lncRNA was H19. Microarray profiling of lung ECs from 2 and 18 months old mice revealed a downregulation of H19 with ageing (-4.1 ± 1.2 fold), qPCR analysis of the same tissue from Ku80+/- progeria mice showed similar effects (-1.7 ± 0.4 fold) compared to WT littermates. In the aortic intima of 20 months old C57BL/6J mice, H19 was also downregulated (-3.7 ± 0.6 fold; P<0.01). siRNA- and LNA GapmeR-mediated knockdown of H19 in human umbilical vein ECs (HUVECs) reduced proliferation and increased the mRNA level of the senescence marker p21 (+2.0 ± 0.2 fold; P<0.01).
In contrast, shear stress significantly upregulated H19 in HUVECs (+3.6 ± 0.6 fold; P<0.01), while it was not upregulated under shear stress after silencing of KLF2. Consistently, H19 expression can be induced by overexpression of KLF2 (+5.0 ± 0.2 fold; P<0.05). Furthermore, the inflammatory activity of ECs was increased after silencing of H19 (ICAM1 +1.4 ± 0.1 fold and VCAM1 +2.3 ± 0.6 fold). Similarly, inflammatory activation of ECs by TNFα also reduced H19 levels (-2.3 ± 0.8 fold). H19 is predominantly located in the cytoplasm of HUVECs and was not bound to silenced or activated histones, suggesting that it exhibits its function independent of epigenetic transcriptional control mechanisms.
In summary, H19 expression is controlled by the shear stress induced transcription factor KLF2 and is downregulated with ageing and inflammation. Functionally, H19 knockdown induces a senescent-like phenotype and increases the inflammatory activity of ECs. Together these results identify H19 as a lncRNA that controls pivotal endothelial functions.
Author Disclosures: P. Hofmann: None. K.M. Michalik: None. A. Doddaballapur: None. S. Dimmeler: None. R. Boon: None.
- © 2014 by American Heart Association, Inc.