Repository logo
 

Epigenetic Regulation of Vascular Smooth Muscle Cells by Histone H3 Lysine 9 Dimethylation Attenuates Target Gene-Induction by Inflammatory Signaling.

Accepted version
Peer-reviewed

No Thumbnail Available

Type

Article

Change log

Authors

Harman, Jennifer L 
Dobnikar, Lina 
Chappell, Joel 
Stokell, Benjamin G 
Dalby, Amanda 

Abstract

OBJECTIVE: Vascular inflammation underlies cardiovascular disease. Vascular smooth muscle cells (VSMCs) upregulate selective genes, including MMPs (matrix metalloproteinases) and proinflammatory cytokines upon local inflammation, which directly contribute to vascular disease and adverse clinical outcome. Identification of factors controlling VSMC responses to inflammation is therefore of considerable therapeutic importance. Here, we determine the role of Histone H3 lysine 9 di-methylation (H3K9me2), a repressive epigenetic mark that is reduced in atherosclerotic lesions, in regulating the VSMC inflammatory response. Approach and Results: We used VSMC-lineage tracing to reveal reduced H3K9me2 levels in VSMCs of arteries after injury and in atherosclerotic lesions compared with control vessels. Intriguingly, chromatin immunoprecipitation showed H3K9me2 enrichment at a subset of inflammation-responsive gene promoters, including MMP3, MMP9, MMP12, and IL6, in mouse and human VSMCs. Inhibition of G9A/GLP (G9A-like protein), the primary enzymes responsible for H3K9me2, significantly potentiated inflammation-induced gene induction in vitro and in vivo without altering NFκB (nuclear factor kappa-light-chain-enhancer of activated B cell) and MAPK (mitogen-activated protein kinase) signaling. Rather, reduced G9A/GLP activity enhanced inflammation-induced binding of transcription factors NFκB-p65 and cJUN to H3K9me2 target gene promoters MMP3 and IL6. Taken together, these results suggest that promoter-associated H3K9me2 directly attenuates the induction of target genes in response to inflammation in human VSMCs. CONCLUSIONS: This study implicates H3K9me2 in regulating the proinflammatory VSMC phenotype. Our findings suggest that reduced H3K9me2 in disease enhance binding of NFκB and AP-1 (activator protein-1) transcription factors at specific inflammation-responsive genes to augment proinflammatory stimuli in VSMC. Therefore, H3K9me2-regulation could be targeted clinically to limit expression of MMPs and IL6, which are induced in vascular disease.

Description

Keywords

arteries, chromatin immunoprecipitation, cytokines, epigenetics, histone, inflammation, Animals, Coronary Artery Disease, Demethylation, Epigenesis, Genetic, Gene Expression, Histone-Lysine N-Methyltransferase, Histones, Humans, Inflammation, Interleukin-6, Male, Matrix Metalloproteinases, Mice, Inbred C57BL, Mitogen-Activated Protein Kinases, Muscle, Smooth, Vascular, Myocytes, Smooth Muscle, NF-kappa B, Transcription Factor AP-1

Journal Title

Arterioscler Thromb Vasc Biol

Conference Name

Journal ISSN

1079-5642
1524-4636

Volume Title

39

Publisher

Ovid Technologies (Wolters Kluwer Health)

Rights

All rights reserved
Sponsorship
British Heart Foundation (CH/2000003)
British Heart Foundation (None)
British Heart Foundation (CH/2000003/12800)
British Heart Foundation (None)
British Heart Foundation (PG/16/11/32021)
British Heart Foundation (None)
British Heart Foundation (None)
British Heart Foundation (FS/15/38/31516)
British Heart Foundation (PG/16/63/32307)
Wellcome Trust (208363/Z/17/Z)
British Heart Foundation