Chromatin Modification and the Endothelial-specific Activation of the E-selectin Gene

Amy Pan,Tucker Collins,Leonard C Edelstein

doi:10.1074/jbc.m412997200

Amy Pan, Tucker Collins + Show 1 more

Open Access

https://doi.org/10.1074/jbc.m412997200

Copy DOI

Abstract

E-selectin plays a role in the binding and extravasation of leukocytes from the bloodstream. The E-selectin gene is rapidly and transiently expressed by endothelial cells activated by inflammatory stimuli. Despite the identification of factors critical for cytokine-induced activation of the E-selectin promoter, little is known about the mechanisms that restrict the gene expression to endothelial cells. We used in vivo approaches to characterize the E-selectin promoter in primary cultures of human umbilical vein endothelial cells and umbilical artery smooth muscle cells. In endothelial cells specifically, nucleosomes are remodeled after tumor necrosis factor (TNF) alpha induction. Chromatin immunoprecipitation analysis demonstrated the binding of the p65 (RelA) component of nuclear factor-kappa B (NF-kappa B) to the endogenous E-selectin promoter after TNFalpha stimulation along with IkappaB kinase alpha. Multiple coactivators, including p300, steroid receptor coactivator-1, and p300/cAMP-response element-binding protein (CREB)-binding protein (CBP)-associated factor localize differentially to the E-selectin promoter. Additionally, TNFalpha induced localized histone hyperacetylation, phosphorylation, and methylation in the E-selectin gene specifically in endothelial cells. Post-induction repression of E-selectin expression is associated with recruitment of multiple deacetylases. Collectively, these studies suggest a model for the selective induction of the E-selectin gene in which the core promoter chromatin architecture is specifically modified in endothelial cells.

Highlights

E-selectin is a member of the selectin family of adhesion molecules that play a central role in the binding and extravasation of leukocytes from the bloodstream into sites of inflammation
Chromatin immunoprecipitation analysis demonstrated the binding of the p65 (RelA) component of nuclear factor-␬B (NF-␬B) to the endogenous E-selectin promoter after tumor necrosis factor (TNF)␣ stimulation along with I␬B kinase ␣
TNF␣ Induces Rapid Expression of the E-selectin Gene—To investigate the sequence of events occurring at the human E-selectin promoter upon induction of the gene by TNF␣, we utilized primary cultures of HUVEC cells, which are known to be responsive to inflammatory cytokines

Summary

Introduction

E-selectin is a member of the selectin family of adhesion molecules that play a central role in the binding and extravasation of leukocytes from the bloodstream into sites of inflammation (for review, see Refs. 1 and 2). Sequences within the first 160 bp upstream of the transcriptional start site, the cytokine response region (CRR), are necessary for efficient cytokine-inducible expression of the human E-selectin promoter in transient transfection assays. The activators that regulate the cytokine response region in the E-selectin promoter are broadly expressed, and the proximal promoter of the E-selectin gene is inducible in both endothelial and non-endothelial cells when it is used in promoter-reporter constructs and transient transfection assays. The histone octamers around which genomic DNA is packed can be extensively modified at their N-terminal tails and can serve as signals to regulatory complexes that can either induce or repress expression of the marked region (for review, see Ref. 20) In this way the histone modifications serve as an epigenetic code that indicates a subset of available genes that can be expressed in a given cell in response to a signal [21]. Neither the localized histone modifications nor the changes in nucleosome positioning take place at the E-selectin locus in vascular smooth muscle cells, suggesting that these chromatin changes are an important part of the endothelial-specific expression of the E-selectin gene

Methods

Results

Conclusion