TY - JOUR
T1 - STAT1 activation by venous malformations mutant Tie2-R849W antagonizes VEGF-A-mediated angiogenic response partly via reduced bFGF production
AU - Huang, Yi Hsien
AU - Wu, Ming Ping
AU - Pan, Shin Chen
AU - Su, Wu Chou
AU - Chen, Yi Wen
AU - Wu, Li Wha
N1 - Funding Information:
Acknowledgments This work was supported by National Science Council (98-2320-B-006-034-MY3, 99-2628-B-006-017-MY3, and 100-2325-B006-005) and Department of Health (DOH-101-TD-C-111-003) to Wu LW. A fellowship for establishing centers of excellence for cancer research from Department of Health, Executive Yuan in Taiwan (DOH100-TD-C-111-003) was awarded to Huang YH. All shRNA plasmids were obtained from the National RNAi Core Facility at the Institute of Molecular Biology/Genomic Research Center, Academia Sinica, supported by the National Research Program for Genomic Medicine Grants by National Science Council (NSC 97-B-3112-B-001-016). All the authors state no conflict of interest.
PY - 2013/1
Y1 - 2013/1
N2 - A missense mutation from arginine to tryptophan at residue 849 in the kinase domain of Tie2 (Tie2-R849W) is commonly identified in familial venous malformations. The mechanistic action of Tie2-R849W variant expression on angiogenic cascades including smooth muscle cell recruitment, however, remains elusive. To avoid confounding factors from endogenous Tie2 expression, Tie2-depleted endothelial cells (ECs) were used to study the effects of ectopic shRNA-resistant Tie2 variant expression, Tie2-WT*and Tie2-R849W*, on vascular cell proliferation, migration, tube formation, and smooth muscle cell (SMC) recruitment. Tie2-R849W*induced STAT1 phosphorylation at Tyr701. Tie2-R849W*-expressing cells had reduced ability to migrate and form tubes on Matrigel than their wildtype counterparts. STAT1 phosphorylation attenuated VEGF-A-induced STAT3 tyrosine phosphorylation in Tie2-R849W*-expressing HUVECs. The induced STAT1 activation also decreased VEGF-A-induced bFGF mRNA expression by competing with activated STAT3 for a direct binding to the consensus STAT-binding site at positions -997 to -989 bp from transcription start site in the bFGF promoter. Depleting STAT1 expression rescued the inability of Tie2-R849W expression to mediate angiogenesis. Moreover, bFGF neutralization or constitutive STAT1 activation, reminiscence of Tie2-R849W*expression, suppressed the smooth muscle cell recruiting ability of endothelial conditioned medium. This work reveals an anti-angiogenic role of STAT1 activation that acts in Tie2-R849W-expressing ECs to impair VEGF-A-mediated STAT3 signaling, bFGF production, and smooth muscle cell recruitment. A balancing activity of STAT1 and STAT3 may be important for Tie2-mediated vascular homeostasis.
AB - A missense mutation from arginine to tryptophan at residue 849 in the kinase domain of Tie2 (Tie2-R849W) is commonly identified in familial venous malformations. The mechanistic action of Tie2-R849W variant expression on angiogenic cascades including smooth muscle cell recruitment, however, remains elusive. To avoid confounding factors from endogenous Tie2 expression, Tie2-depleted endothelial cells (ECs) were used to study the effects of ectopic shRNA-resistant Tie2 variant expression, Tie2-WT*and Tie2-R849W*, on vascular cell proliferation, migration, tube formation, and smooth muscle cell (SMC) recruitment. Tie2-R849W*induced STAT1 phosphorylation at Tyr701. Tie2-R849W*-expressing cells had reduced ability to migrate and form tubes on Matrigel than their wildtype counterparts. STAT1 phosphorylation attenuated VEGF-A-induced STAT3 tyrosine phosphorylation in Tie2-R849W*-expressing HUVECs. The induced STAT1 activation also decreased VEGF-A-induced bFGF mRNA expression by competing with activated STAT3 for a direct binding to the consensus STAT-binding site at positions -997 to -989 bp from transcription start site in the bFGF promoter. Depleting STAT1 expression rescued the inability of Tie2-R849W expression to mediate angiogenesis. Moreover, bFGF neutralization or constitutive STAT1 activation, reminiscence of Tie2-R849W*expression, suppressed the smooth muscle cell recruiting ability of endothelial conditioned medium. This work reveals an anti-angiogenic role of STAT1 activation that acts in Tie2-R849W-expressing ECs to impair VEGF-A-mediated STAT3 signaling, bFGF production, and smooth muscle cell recruitment. A balancing activity of STAT1 and STAT3 may be important for Tie2-mediated vascular homeostasis.
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U2 - 10.1007/s10456-012-9313-x
DO - 10.1007/s10456-012-9313-x
M3 - Article
C2 - 23086340
AN - SCOPUS:84871613282
SN - 0969-6970
VL - 16
SP - 207
EP - 222
JO - Angiogenesis
JF - Angiogenesis
IS - 1
ER -