Endothelial NO Synthase-Dependent S-Nitrosylation of β-Catenin Prevents Its Association with TCF4 and Inhibits Proliferation of Endothelial Cells Stimulated by Wnt3a

ABSTRACT

Nitric oxide (NO) produced by endothelial NO synthase (eNOS) modulates many functions in endothelial cells. S-nitrosylation (SNO) of cysteine residues on β-catenin by eNOS-derived NO has been shown to influence intercellular contacts between endothelial cells. However, the implication of SNO in the regulation of β-catenin transcriptional activity is ill defined. Here, we report that NO inhibits the transcriptional activity of β-catenin and endothelial cell proliferation induced by activation of Wnt/β-catenin signaling. Interestingly, induction by Wnt3a of β-catenin target genes, such as the axin2 gene, is repressed in an eNOS-dependent manner by vascular endothelial growth factor (VEGF). We identified Cys466 of β-catenin as a target for SNO by eNOS-derived NO and as the critical residue for the repressive effects of NO on β-catenin transcriptional activity. Furthermore, we observed that Cys466 of β-catenin, located at the binding interface of the β-catenin–TCF4 transcriptional complex, is essential for disruption of this complex by NO. Importantly, Cys466 of β-catenin is necessary for the inhibitory effects of NO on Wnt3a-stimulated proliferation of endothelial cells. Thus, our data define the mechanism responsible for the repressive effects of NO on the transcriptional activity of β-catenin and link eNOS-derived NO to the modulation by VEGF of Wnt/β-catenin-induced endothelial cell proliferation.

KEYWORDS:

• VEGF
• Wnts
• cell signaling
• endothelial cells
• nitric oxide
• nitric oxide synthase
• S-nitrosylation

Supplemental material for this article may be found at https://doi.org/10.1128/MCB.00089-17.

ACKNOWLEDGMENTS

This work was supported by grants from the Canadian Institutes of Health Research to J.-P.G. (MOP-86464 and MOP-142180). J.-P.G. holds a Université de Montréal research chair and was in receipt of a Fonds de Recherche du Québec-Santé (FRQS) senior career award.

We thank Huiming Cao, Jianjie Fu, and Aiqian Zhang (Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences) for their help with the molecular modeling.

Y.Z. and R.C. designed and performed experiments, analyzed data, prepared figures, and wrote the manuscript; C.D. performed some of the experiments and analyzed data; J.-P.G. designed and supervised the experiments, analyzed the data, prepared the figures, and wrote the manuscript.

We declare that we have no conflict of interest.