Endothelial RSPO3 Controls Vascular Stability and Pruning through Non-canonical WNT/Ca2+/NFAT Signaling

• Published in: Developmental cell Vol. 36; no. 1; pp. 79 - 93
• Main Authors: Scholz, Beate, Korn, Claudia, Wojtarowicz, Jessica, Mogler, Carolin, Augustin, Iris, Boutros, Michael, Niehrs, Christof, Augustin, Hellmut G.
• Format: Journal Article
• Language: English
• Published: Elsevier Inc 11.01.2016
• Subjects: angiogenesis; Moyamoya; NFAT; non-canonical WNT pathway; R-spondin; RNF213; RSPO3; vascular pruning; vascular regression; vascular remodeling; WNT; vascular regression; RNF213; angiogenesis; Moyamoya; vascular pruning; RSPO3; R-spondin; vascular remodeling; WNT; non-canonical WNT pathway; NFAT
• ISSN: 1534-5807; 1878-1551
• DOI: 10.1016/j.devcel.2015.12.015

The WNT signaling enhancer R-spondin3 (RSPO3) is prominently expressed in the vasculature. Correspondingly, embryonic lethality of Rspo3-deficient mice is caused by vessel remodeling defects. Yet the mechanisms underlying vascular RSPO3 function remain elusive. Inducible endothelial Rspo3 deletion (Rspo3-iECKO) resulted in perturbed developmental and tumor vascular remodeling. Endothelial cell apoptosis and vascular pruning led to reduced microvessel density in Rspo3-iECKO mice. Rspo3-iECKO mice strikingly phenocopied the non-canonical WNT signaling-induced vascular defects of mice deleted for the WNT secretion factor Evi/Wls. An endothelial screen for RSPO3 and EVI/WLS co-regulated genes identified Rnf213, Usp18, and Trim30α. RNF213 targets filamin A and NFAT1 for proteasomal degradation attenuating non-canonical WNT/Ca2+ signaling. Likewise, USP18 and TRIM5α inhibited NFAT1 activation. Consequently, NFAT protein levels were decreased in endothelial cells of Rspo3-iECKO mice and pharmacological NFAT inhibition phenocopied Rspo3-iECKO mice. The data identify endothelial RSPO3-driven non-canonical WNT/Ca2+/NFAT signaling as a critical maintenance pathway of the remodeling vasculature. [Display omitted] •Rspo3 deletion from EC mimics the vessel regression phenotype of Evi-iECKO mice•Rnf213, Usp18, and Trim30α are upregulated upon silencing of EC-derived Rspo3•RNF213, USP18, and TRIM5α attenuate WNT/Calcium/NFAT signaling in vitro•Blocking of NFAT activation in vivo by CsA phenocopies Rspo3 deletion from EC RSPO3 is an enhancer of WNT signaling. Scholz, Korn et al. show increased vessel regression upon silencing of endothelial cell (EC)-derived Rspo3. Rspo3 deletion increases Rnf213, Usp18, and Trim30α expression in EC, which block non-canonical WNT/calcium signaling at the level of NFAT, thus leading to the vessel regression phenotype of Rspo3-iECKO mice.