Lipoproteins and endothelial cell function. Regulation of gene expression

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.

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Abstract 18412: Long Non-coding RNA Meg3 Regulates Senescence-associated Genes and Controls Endothelial Cell Function

Circulation ◽

10.1161/circ.130.suppl_2.18412 ◽

2014 ◽

Vol 130 (suppl_2) ◽

Author(s):

Reinier Boon ◽

Patrick Hofmann ◽

Katharina Michalik ◽

Andrea Knau ◽

Yuliya Ponomareva ◽

...

Keyword(s):

Gene Expression ◽

Endothelial Cells ◽

Cell Function ◽

Regulation Of Gene Expression ◽

Global Gene Expression ◽

Exon Array ◽

Protein Coding ◽

Endothelial Cell Function ◽

Sprouting Angiogenesis

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.

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Endothelial Cell Function, Including Tissue Factor Expression, Under Flow Conditions

Thrombosis and Haemostasis ◽

10.1055/s-0038-1642664 ◽

1995 ◽

Vol 74 (01) ◽

pp. 123-128 ◽

Cited By ~ 40

Author(s):

Eric F Grabowski ◽

Frances P Lam

Keyword(s):

Endothelial Cell ◽

Tissue Factor ◽

Cell Function ◽

Tissue Factor Expression ◽

Flow Conditions ◽

Endothelial Cell Function ◽

Factor Expression

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Do DPP-4 inhibitors improve endothelial cell function?

10.35841/cardiology.1.1.12-14 ◽

2017 ◽

Vol 01 (01) ◽

Author(s):

Hiroshi Nomoto ◽

Hideaki Miyoshi ◽

Akinobu Nakamura ◽

Tatsuya Atsumi ◽

Naoki Manda ◽

...

Keyword(s):

Endothelial Cell ◽

Cell Function ◽

Endothelial Cell Function

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Estrogen Restores Endothelial Cell Function in an Experimental Model of Vascular Injury

Circulation ◽

10.1161/01.cir.96.5.1624 ◽

1997 ◽

Vol 96 (5) ◽

pp. 1624-1630 ◽

Cited By ~ 60

Author(s):

C. Roger White ◽

Jonathan Shelton ◽

Shi-Juan Chen ◽

Victor Darley-Usmar ◽

Leslie Allen ◽

...

Keyword(s):

Endothelial Cell ◽

Experimental Model ◽

Vascular Injury ◽

Cell Function ◽

Endothelial Cell Function

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Vascular adaptation in pregnancy and endothelial dysfunction in preeclampsia

Journal of Endocrinology ◽

10.1530/joe-16-0340 ◽

2017 ◽

Vol 232 (1) ◽

pp. R27-R44 ◽

Cited By ~ 90

Author(s):

D S Boeldt ◽

I M Bird

Keyword(s):

Endothelial Cell ◽

Endothelial Dysfunction ◽

Cell Function ◽

Endothelial Cell Dysfunction ◽

Hypertensive Disorders Of Pregnancy ◽

Endothelial Cell Function ◽

Vascular Adaptation ◽

Cell Dysfunction ◽

Maternal Adaptation ◽

Flow Through

Maternal vascular adaptation to pregnancy is critically important to expand the capacity for blood flow through the uteroplacental unit to meet the needs of the developing fetus. Failure of the maternal vasculature to properly adapt can result in hypertensive disorders of pregnancy such as preeclampsia (PE). Herein, we review the endocrinology of maternal adaptation to pregnancy and contrast this with that of PE. Our focus is specifically on those hormones that directly influence endothelial cell function and dysfunction, as endothelial cell dysfunction is a hallmark of PE. A variety of growth factors and cytokines are present in normal vascular adaptation to pregnancy. However, they have also been shown to be circulating at abnormal levels in PE pregnancies. Many of these factors promote endothelial dysfunction when present at abnormal levels by acutely inhibiting key Ca2+ signaling events and chronically promoting the breakdown of endothelial cell–cell contacts. Increasingly, our understanding of how the contributions of the placenta, immune cells, and the endothelium itself promote the endocrine milieu of PE is becoming clearer. We then describe in detail how the complex endocrine environment of PE affects endothelial cell function, why this has contributed to the difficulty in fully understanding and treating this disorder, and how a focus on signaling convergence points of many hormones may be a more successful treatment strategy.

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