Abstract: FR-PO199

Endothelial Glucocorticoid Receptor (GR) Modulates Wnt Signaling in a Mouse Model of Atherosclerosis

Session Information

Category: Hypertension

  • 1103 Vascular Biology and Dysfunction

Authors

  • Zhou, Han, Yale University School of Medicine, New Haven, Connecticut, United States
  • Goodwin, Julie, Yale University School of Medicine, New Haven, Connecticut, United States
Background

Apo E KO/endothelial GR double knock-out (DKO) mice develop more severe atherosclerotic lesions compared to Apo E KO mice alone. Genomic data from ChIP-seq and RNA-seq experiments in endothelial cells indicate that endothelial GR binding to genes in the Wnt signaling pathway is enriched. The Wnt signaling pathway is a potentially important, yet understudied, mediator of vascular inflammation.

Methods

Male Apo E KO mice and Apo E KO/endothelial GR double knock-out mice (DKO) were bred to mice carrying the BAT GAL reporter to enable visualization of the activation of the canonical Wnt signaling pathway. Mice were fed a high-fat diet for 4-5 weeks and then sacrified for blood and tissue processing. Whole aortas and cross sections of brachiocephalics arteries were stained with X-gal. Brachiocephalics were also subjected to double immunofluorescent staining with antibodies to BAT GAL and CD31. Luciferase assay was used to invesigate modulation of canonical Wnt signaling by GR in vitro using mouse lung endothelial cells subjected to GR siRNA knockdown and treatment with Wnt3a, a canonical Wnt ligand.

Results

BAT GAL+ Cre+ mice had significantly more aortic area stained after X-gal than did BAT GAL+ Cre- mice (32% vs. 6%, p=.0061, n=5/group). Staining of BAT GAL- Cre- mice was used as a control. X gal staining in brachiocephalic arteries was also signficantly increased in BAT GAL+ Cre+ mice compared to BAT GAL+ Cre- littermate controls. TCF/LEF luciferase assay demonstrated a 3-fold higher induction in Wnt3a-treated GR knockdown cells compared to similarly treated GR replete cells.

Conclusion

We conclude from these results that:
1. Loss of endothelial GR augments canonical Wnt signaling both in vivo and in vitro
2. Modulation of the Wnt pathway may represent a novel therapeutic strategy for treatment of vascular disease

Representative images of whole aortas stained with X gal after 4-5 weeks of high fat diet feeding.

Funding

  • Other NIH Support