Background and aims EZH2 is an epigenetic regulator that trimethylates lysine 27 of histone 3 (H3K27me3). We have previously suggested that increased EZH2 might be mediating a pro-inflammatory epigenetic reprograming of naïve CD4+ T cells as an early event in lupus flares. Here we examined how overexpression of EZH2 affects the DNA methylome and function in CD4+ T cells.
Methods Naïve CD4+ T cells were isolated from lupus patients and healthy controls. EZH2 was overexpressed, and genome-wide DNA methylation changes were evaluated. Gene expression and miRNAs were assessed by qPCR while protein expression was examined by Western blotting. A cell adhesion assay was used to assess adhesion of T cells to human microvascular endothelial cells (HMVEC).
Results EZH2 expression and H3k27me3 were increased in naïve CD4+ T cells in lupus compared to healthy controls. Both miR-26a and miR-101, which regulate EZH2, were decreased. DNA methylation analysis identified 156 hypomethylated and 168 hypermethylated CpG sites in naïve CD4+ T cells transfected with EZH2. Genes involved in leukocyte adhesion and migration, such as F11R encoding JAM-A (junctional adhesion molecule A), and SELPLG encoding PSGL-1 (P-selectin glycoprotein ligand 1), were hypomethylated. Overexpression of EZH2 resulted in ˜2-fold increased adhesion of CD4+ T cells to endothelial cells. Pre-incubation of EZH2-transfected CD4+ T cells with neutralising antibodies against JAM-A significantly blunted cell adhesion.
Conclusions We uncovered an important role for EZH2 in T cell adhesion. EZH2 overexpression results in hypomethylation of JAM-A, which might increase the migratory ability of T cells and contribute to aggressive T cell extravasation in lupus.
- © 2017, Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions
Statistics from Altmetric.com
If you wish to reuse any or all of this article please use the link below which will take you to the Copyright Clearance Center’s RightsLink service. You will be able to get a quick price and instant permission to reuse the content in many different ways.