Transcriptional networks specifying homeostatic and inflammatory programs of gene expression in human aortic endothelial cells

Endothelial cells (ECs) are critical determinants of vascular homeostasis and inflammation, but transcriptional mechanisms specifying their identities and functional states remain poorly understood. Here, we report a genome-wide assessment of regulatory landscapes of primary human aortic endothelial cells (HAECs) under basal and activated conditions, enabling inference of transcription factor networks that direct homeostatic and pro-inflammatory programs. We demonstrate that 43% of detected enhancers are EC-specific and contain SNPs associated to cardiovascular disease and hypertension. We provide evidence that AP1, ETS, and GATA transcription factors play key roles in HAEC transcription by co-binding enhancers associated with EC-specific genes. We further demonstrate that exposure of HAECs to oxidized phospholipids or pro-inflammatory cytokines results in signal-specific alterations in enhancer landscapes and associate with coordinated binding of CEBPD, IRF1, and NFκB. Collectively, these findings identify cis-regulatory elements and corresponding trans-acting factors that contribute to EC identity and their specific responses to pro-inflammatory stimuli.

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Abstract 41: Transcriptional Networks Specifying Homeostatic and Pro-Inflammatory Programs of Gene Expression in Human Aortic Endothelial Cells

Arteriosclerosis Thrombosis and Vascular Biology ◽

10.1161/atvb.37.suppl_1.41 ◽

2017 ◽

Vol 37 (suppl_1) ◽

Author(s):

Casey E Romanoski ◽

Nicholas T Hogan ◽

Michael Whalen ◽

Lindsey K Stolze ◽

Michael T Lam ◽

...

Keyword(s):

Gene Expression ◽

Endothelial Cells ◽

Regulatory Elements ◽

Transcriptional Networks ◽

Aortic Endothelial Cells ◽

Genome Wide ◽

A Genome ◽

Inflammatory Stimuli ◽

Human Aortic Endothelial Cells ◽

Aortic Endothelial

Endothelial cells are critical determinants of vascular homeostasis and inflammation, but transcriptional mechanisms specifying their identities and functional states remain poorly understood. Here, we report a genome-wide assessment of regulatory landscapes in primary human aortic endothelial cells (HAECs) under basal and activated conditions, enabling inference of transcription factor networks that direct homeostatic and pro-inflammatory programs of gene expression. We provide evidence that AP1, ETS, and GATA transcription factors play key roles in establishing HAEC identity by co-binding at many enhancers associated with EC-specific genes. We further demonstrate that exposure of HAECs to oxidized phospholipids or pro-inflammatory cytokines results in signal-specific alterations in enhancer landscapes that are associated with coordinated binding of CEBPD, IRF1 and NFkB. Collectively, these findings identify cis-regulatory elements and corresponding trans-acting factors that contribute to endothelial cell identity and their specific responses to pro-inflammatory stimuli.

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TRAIL inhibits oxidative stress in human aortic endothelial cells exposed to pro‐inflammatory stimuli

Physiological Reports ◽

10.14814/phy2.14612 ◽

2020 ◽

Vol 8 (20) ◽

Author(s):

Hannah Forde ◽

Emma Harper ◽

Keith D. Rochfort ◽

Robert G. Wallace ◽

Colin Davenport ◽

...

Keyword(s):

Oxidative Stress ◽

Endothelial Cells ◽

Aortic Endothelial Cells ◽

Inflammatory Stimuli ◽

Human Aortic Endothelial Cells ◽

Aortic Endothelial

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Abstract 611: AP-1 and ETS Family Transcription Factors Co-localize at Enhancers in Human Aortic Endothelial Cells

Arteriosclerosis Thrombosis and Vascular Biology ◽

10.1161/atvb.35.suppl_1.611 ◽

2015 ◽

Vol 35 (suppl_1) ◽

Author(s):

Nicholas T Hogan ◽

Casey E Romanoski ◽

Michael T Lam ◽

Christopher K Glass

Keyword(s):

Endothelial Cells ◽

Transcription Factor ◽

Transcription Factors ◽

De Novo ◽

Regulatory Elements ◽

Specific Gene ◽

Motif Analysis ◽

Aortic Endothelial Cells ◽

Human Aortic Endothelial Cells ◽

Aortic Endothelial

Introduction: Sequence-specific transcription factors bind DNA regulatory elements and play a key role in establishing cellular identity. Studies comparing macrophages to B cells have revealed that small numbers of such collaborative or lineage-determining transcription factors (LDTF) establish distinct enhancers in each cell type. These factors also allow for the binding of signal dependent transcription factors. Here we present data which suggest members of the AP-1, ETS, and STAT transcription factor families serve as collaborative transcriptional regulators in human aortic endothelial cells (HAEC). Hypothesis: We hypothesize that a set of AP-1 and ETS transcription factors collaborate to establish key endothelial cell enhancers. Methods: Working in HAEC, we measured poised and active enhancers using ChIP-seq for the epigenetic histone modifications H3K4me2 and H3K27Ac, performed motif analysis, and measured transcription factor binding for candidate factors. Knockdowns of JUN, ERG, and STAT3 followed by RNA-seq were used to evaluate altered enhancer function and gene targets of candidate factors. Results: Our de novo motif analysis revealed that motifs for ETS and AP-1 transcription factors are highly enriched at HAEC enhancers. ChIP-seq experiments for JUN, JUNB, ERG, and STAT3 showed between 8,000 and 55,000 intergenic peaks for each factor. Together these peaks bind 50% of poised enhancers, with a subset co-localizing at these sites. Gene ontology analysis showed that gene targets of these enhancers are involved in endothelial-specific functions. Further, knockdown of JUN, ERG, and STAT3 resulted in a twofold or greater change in expression of hundreds of HAEC transcripts. Conclusion: The genome-wide pattern of JUN, JUNB, ERG, and STAT3 co-localization at enhancers in HAEC suggests these factors serve as key regulators that collaboratively modulate endothelial-specific gene expression. Further investigation of candidate lineage-determining transcription factors using pro-atherogenic signals could reveal regulatory mechanisms of disease-relevant endothelial transcriptional programs.

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