Endothelial cell-derived non-canonical Wnt ligands control vascular pruning in angiogenesis.
Multiple cell types involved in the regulation of angiogenesis express Wnt ligands. Although β-catenin dependent and independent Wnt signaling pathways have been shown to control angiogenesis, the contribution of individual cell types to activate these downstream pathways in endothelial cells (ECs) during blood vessel formation is still elusive. To investigate the role of ECs in contributing Wnt ligands for regulation of blood vessel formation, we conditionally deleted the Wnt secretion factor Evi in mouse ECs (Evi-ECKO). Evi-ECKO mice showed decreased microvessel density during physiological and pathological angiogenesis in the postnatal retina and in tumors, respectively. The reduced microvessel density resulted from increased vessel regression accompanied by decreased EC survival and proliferation. Concomitantly, survival-related genes were downregulated and cell cycle arrest- and apoptosis-inducing genes were upregulated. EVI silencing in cultured HUVECs showed similar target gene regulation, supporting a mechanism of EC-derived Wnt ligands in controlling EC function. ECs preferentially expressed non-canonical Wnt ligands and canonical target gene expression was unaffected in Evi-ECKO mice. Furthermore, the reduced vascularization of Matrigel plugs in Evi-ECKO mice could be rescued by introduction of non-canonical Wnt5a. Treatment of mouse pups with the non-canonical Wnt inhibitor TNP470 resulted in increased vessel regression accompanied by decreased EC proliferation, thus mimicking the proliferation-dependent Evi-ECKO remodeling phenotype. Taken together, this study identified EC-derived non-canonical Wnt ligands as regulators of EC survival, proliferation and subsequent vascular pruning during developmental and pathological angiogenesis.
Division of Vascular Oncology and Metastasis, German Cancer Research Center (DKFZ-ZMBH Alliance), Heidelberg 69221, Germany.
Claudia
C
Korn
Beate
B
Scholz
Junhao
J
Hu
Kshitij
K
Srivastava
Jessica
J
Wojtarowicz
Tabea
T
Arnsperger
Ralf H
RH
Adams
Michael
M
Boutros
Hellmut G
HG
Augustin
Iris
I
Augustin
D000818:Animals; D000831:Animals, Newborn; D017209:Apoptosis / Q000187:drug effects / Q000235:genetics; D019898:Autocrine Communication / Q000187:drug effects / Q000235:genetics; D002452:Cell Count; D049109:Cell Proliferation / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D003510:Cyclohexanes / Q000494:pharmacology; D004268:DNA-Binding Proteins / Q000378:metabolism; D042783:Endothelial Cells / Q000187:drug effects / Q000378:metabolism*; D005786:Gene Expression Regulation / Q000187:drug effects; D061307:Human Umbilical Vein Endothelial Cells / Q000187:drug effects / Q000378:metabolism; D006801:Humans; D008024:Ligands; D000074008:MDS1 and EVI1 Complex Locus Protein; D051379:Mice; D008822:Mice, Transgenic; D008954:Models, Biological; D009389:Neovascularization, Pathologic / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D018919:Neovascularization, Physiologic / Q000187:drug effects / Q000235:genetics; D000077609:O-(Chloroacetylcarbamoyl)fumagillol; D010641:Phenotype; D011519:Proto-Oncogenes; D012160:Retina / Q000254:growth & development / Q000378:metabolism; D012717:Sesquiterpenes / Q000494:pharmacology; D015398:Signal Transduction / Q000187:drug effects / Q000235:genetics; D014157:Transcription Factors / Q000378:metabolism; D051153:Wnt Proteins / Q000378:metabolism*
D003510:Cyclohexanes; D004268:DNA-Binding Proteins; D008024:Ligands; D000074008:MDS1 and EVI1 Complex Locus Protein; C499305:Mecom protein, mouse; D012717:Sesquiterpenes; D014157:Transcription Factors; D051153:Wnt Proteins; D000077609:O-(Chloroacetylcarbamoyl)fumagillol
Angiogenesis; Evi; Mouse; Vessel regression; Wnt