Abstract 18611: JMJD2B Regulates Endothelial to Mesenchymal Cell Transition
Introduction: Endothelial to mesenchymal transition (EndMT) is a variation of epithelial to mesenchymal transition (EMT). The process of EndMT comprises the transition of an endothelial cell (EC) to a mesenchymal cell, like muscle or fibroblastic cell type. EndMT is a physiological process in development and tissue regeneration but also contributes to pathophysiological conditions like organ or tissue fibrosis. The JmjC domain-containing protein JMJD2B is a histone demethylase and promotes the progression of EMT by regulating gene expression. The aim of this study was to investigate whether JMJD2B regulates EndMT in human umbilical vein endothelial cells (HUVECs).
Methods and Results: We used TGF-β2 to induce EndMT in HUVECs. We showed that FGF2, which is a regular component of EC culture media, inhibits TGF-β2 induced EndMT as shown by measurement of the mesenchymal genes smooth muscle 22 (SM22) and calponin on mRNA and protein level. Indeed, ECs underwent TGF-β2 induced EndMT only when using medium not supplemented with FGF2. Under FGF2-deficient conditions, TGF-ß2 significantly induced SM22 (28.8±3.2 fold) and calponin (189.2±54.5 fold; both p<0.05). To examine whether JMJD2B is involved in EndMT, JMJD2B expression was silenced by siRNA (-52.4±5.3%). Moreover, knockdown of JMJD2B resulted in a significant decrease of SM22 (-50.2±5.6%) and calponin (-62.9±6.8%) on mRNA and protein level during TGF-β2 induced EndMT in ECs (both p<0.05). Next we used a microarray approach to identify JMJD2B target genes during EndMT. Indeed, the extracellular matrix modifying sulfatase SULF1, which has been implicated in healing after myocardial infarction, was induced during EndMT (20.6±8.1 fold, p<0.05) and significantly reduced after siJMJD2B (-69.5±6.2%, p<0.05). In vivo studies revealed a significant correlation of JMJD2B with SULF1 in the aorta of mice (R=0.75, p=0.007), while SULF1 was increased in the aorta of apoE-/- mice after high fat diet (p<0.05). Finally, using ChIP assay, we detected JMJD2B bound to the promoter of SULF1 during EndMT coinciding with an increase of the transcriptional activating chromatin mark H3K4me3.
Conclusion: JMJD2B is a positive regulator of EndMT in ECs and transcriptionally regulates the sulfatase SULF1.
Author Disclosures: S. Glaser: None. J. Boeckel: None. D. John: None. C. Döring: None. S. Cremer: None. S. Dimmeler: None.
- © 2016 by American Heart Association, Inc.