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Updated: Jul 6, 2026
06:51
A Patient-Derived Xenograft Model for Venous Malformation
Published on: June 15, 2020
Tie2-R849W mutant in venous malformations chronically activates a functional STAT1 to modulate gene expression
Hsiao-Tang Hu1, Yi-Hsien Huang, Yi-Ann Chang
1Institute of Molecular Medicine, College of Medicine, National Cheng Kung University, Tainan, Taiwan, ROC.
The Journal of Investigative Dermatology
|April 11, 2008
Summary
A Tie2 receptor mutation (Tie2-R849W) linked to venous malformations causes ligand-independent activation, affecting endothelial cell behavior and STAT1 signaling. Further research is needed to clarify its role in VMs.
Area of Science:
- Molecular Biology
- Cell Biology
- Biochemistry
Background:
- Tie2 is an endothelial receptor tyrosine kinase implicated in vascular development.
- A specific mutation, Tie2-R849W, results in ligand-independent kinase activation.
- This mutation is associated with familial venous malformations (VMs) but its mechanism is unclear.
Purpose of the Study:
- To investigate the effects of wild-type, kinase-dead (K855A), and constitutively active (R849W) Tie2 expression on endothelial cells.
- To elucidate the downstream signaling pathways affected by Tie2-R849W.
- To understand the role of Tie2 signaling in the pathogenesis of venous malformations.
Main Methods:
- Adenoviral infection to express different Tie2 variants in endothelial cells.
- Assays for endothelial cell proliferation, apoptosis, migration, and tube formation.
- Analysis of STAT1 phosphorylation and STAT1-responsive gene promoter activity (IRF1).
- Investigation of involvement of JNK and p38MAPK signaling pathways.
Main Results:
- Ectopic Tie2 expression modulated endothelial cell proliferation, apoptosis, and migration.
- Tie2-R849W showed ligand-independent activation, conferring apoptosis resistance but impairing tube formation.
- Tie2-R849W induced chronic STAT1 phosphorylation and IRF1 promoter activity, dependent on JNK signaling.
- Kinase activity was essential for Tie2-mediated migration.
Conclusions:
- The Tie2-R849W mutation alters endothelial cell behavior and activates STAT1 signaling pathways.
- JNK activation is crucial for Tie2-R849W-mediated IRF1 promoter activity.
- Further investigation into STAT1's role in venous malformations is warranted.
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