Rationale:
Wnt signaling plays a key role in the development and the regeneration of neovessels, however, the underlying mechanisms of these processes are not clearly understood.
Goal:
To elucidate the mechanism of dedifferentiation of venous endothelial cells (VECs) to arterial (A)ECs.
Methods and Results:
Herein we demonstrate that 6-bromoindirubin-3'-oxime (BIO), an inhibitor of Glycogen Synthase Kinase (GSK)-3β elicits the stabilization and the nuclear accumulation of β-catenin, thereby its direct interaction with the transcription factor NANOG in the nucleus of ECs. In a ChiP experiment, NANOG protein bound to the
NANOG-,
BRACHYURY-,
CD133-
and
VEGFR2
-promoters in these cells. In a cell-based assay, BIO induced the activation of the
NANOG
-promoter-luciferase reporter system. Accordingly, stimulation of VECs with BIO increased Notch-1, Ephrin-B2 and Hey2 expressions, indicating dedifferentiation these cells to AECs. While NANOG-depletion decreased BIO-induced NOTCH-1 expression and neovascularization. BIO increased Matrigel plug neovessel formation in nude mice. Immunostaining of Matrigel plug sections prepared from these mice showed increased expression of Notch-1, Ephrin-B2 and Hey2, indicating dedifferentiation of a subset of VECs into AECs. In a mouse model of hind limb ischemia, BIO induced the incorporation of VECs into collateral neovessels as characterized by Ephrin-B2- and Hey2-positivities, and smooth muscle cell recruitment.
Summary:
Thus, we show that a subset of mature VECs may retain the ability to dedifferentiate into AECs
in vivo
and suggest critical roles of GSK-3β inhibition in this process.
GSK-3β in Pancreatic Cancer: Spotlight on 9-ING-41, Its Therapeutic Potential and Immune Modulatory Properties
