PUBLICATION
Basal Flt1 tyrosine kinase activity is a positive regulator of endothelial survival and vascularization during zebrafish embryogenesis
- Authors
- Li, S., Zhou, X.L., Dang, Y.Y., Kwan, Y.W., Chan, S.W., Leung, G.P., Lee, S.M., Hoi, M.P.
- ID
- ZDB-PUB-141203-45
- Date
- 2015
- Source
- Biochimica et biophysica acta. General subjects 1850(2): 373-384 (Journal)
- Registered Authors
- Keywords
- Calycosin, Endothelial cell, Flt1, Molecular docking, VEGF receptor inhibitor, Zebrafish
- MeSH Terms
-
- Androstadienes/pharmacology
- Animals
- Cell Survival/drug effects
- Cell Survival/physiology
- Embryo, Nonmammalian/cytology
- Embryo, Nonmammalian/embryology*
- Embryonic Development/drug effects
- Embryonic Development/physiology*
- Endothelium, Vascular/cytology
- Endothelium, Vascular/embryology*
- Human Umbilical Vein Endothelial Cells/cytology
- Human Umbilical Vein Endothelial Cells/metabolism
- Humans
- Isoflavones/pharmacology
- Neovascularization, Physiologic/drug effects
- Neovascularization, Physiologic/physiology*
- Phosphatidylinositol 3-Kinases/antagonists & inhibitors
- Phosphatidylinositol 3-Kinases/genetics
- Phosphatidylinositol 3-Kinases/metabolism
- Protein Kinase Inhibitors/pharmacology
- Proto-Oncogene Proteins c-akt/genetics
- Proto-Oncogene Proteins c-akt/metabolism
- Signal Transduction/drug effects
- Signal Transduction/physiology
- Vascular Endothelial Growth Factor Receptor-1/antagonists & inhibitors
- Vascular Endothelial Growth Factor Receptor-1/genetics
- Vascular Endothelial Growth Factor Receptor-1/immunology*
- Zebrafish/embryology*
- Zebrafish/genetics
- Zebrafish Proteins/antagonists & inhibitors
- Zebrafish Proteins/genetics
- Zebrafish Proteins/immunology*
- PubMed
- 25450186 Full text @ BBA General Subjects
Citation
Li, S., Zhou, X.L., Dang, Y.Y., Kwan, Y.W., Chan, S.W., Leung, G.P., Lee, S.M., Hoi, M.P. (2015) Basal Flt1 tyrosine kinase activity is a positive regulator of endothelial survival and vascularization during zebrafish embryogenesis. Biochimica et biophysica acta. General subjects. 1850(2):373-384.
Abstract
Background The role of Kdr (VEGFR-2/Flk-1) in vascular formation has been well described, but the role of Flt1 (VEGFR-1) is not well studied and is generally considered as a decoy receptor for trapping VEGF.
Methods The effects of VEGFR1/2 kinase inhibitor (VRI) and calycosin on Flt1 tyrosine kinase (TK) activity were evaluated by molecular docking, enzymatic inhibition assay, protein co-immunoprecipitation and siRNA gene knock-down analysis in HUVECs. Toxicities of the chemicals were examined using HUVECs viability. Their effects on angiogenesis and vessel formation were furthered studied in HUVECs in vitro and Tg(fli-1:EGFP) zebrafish in vivo. The gene and protein expression of VEGF and VEGF receptors were investigated by quantitative RT-PCR and Western blot.
Results VRI strongly inhibited physiological functions of both VEGF receptors and suppressed endothelial cell survival. This resulted in blood vessel loss in zebrafish embryos. Interestingly, calycosin co-treatment impeded VRI-induced blood vessel loss. Docking and kinase inhibition assay revealed that calycosin competed with VRI for the tyrosine kinase domain of Flt1 without affecting ATP binding. On the contrary, calycosin did not affect the interaction between VRI and Kdr-TK. Consistent with these results, calycosin counteracted the inhibition of Flt1-TK and PI3K phosphorylation induced by VRI in HUVECs. Further studies in vitro and in vivo showed that the minimizing effect of calycosin on VRI-mediated endothelial cytotoxicity was blocked by wortmannin (a PI3K inhibitor). The impeding effect of calycosin on VRI-induced blood vessel loss was absent in zebrafish embryos injected with Flt1 MO.
Conclusions Flt1-tyrosine kinase (TK) activity contributed significantly in endothelial cells survival and vascular development during embryo angiogenesis in zebrafish by engaging PI3K/Akt pathway.
General significance The roles of Flt1 activity in endothelial cell survival in physiological vascular formation may have been previously under-appreciated.
Genes / Markers
Expression
Phenotype
Mutations / Transgenics
Human Disease / Model
Sequence Targeting Reagents
Fish
Orthology
Engineered Foreign Genes
Mapping