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Updated: Aug 16, 2026

Visualization and Quantitative Analysis of Embryonic Angiogenesis in Xenopus tropicalis
Published on: May 25, 2017
Regulation of tie2 expression by angiopoietin--potential feedback system
Tomoki Hashimoto1, Yongqin Wu, Nancy Boudreau
1Department of Anesthesia and Perioperative Care and the Center for Cerebrovascular Research, University of California, San Francisco, California 94110, USA. hashimot@anesthesia.ucsf.edu
Abstract:
To study a potential feedback system in the angiopoietin (Ang)-Tie2 system, the authors examined effects of Ang1 and Ang2 on Tie2 expression on human umbilical vein endothelial cells (HUVECs) with or without stimulation by a potent inflammatory cytokine, tumor necrosis factor-alpha (TNF-alpha). Ang1, but not Ang2, down-regulated Tie2 expression on HUVECs without TNF-alpha stimulation. Both Ang1 and Ang2 attenuated TNF-alpha-induced Tie2 up-regulation. Regulation of Tie2 expression by Ang1 or Ang2 was not dependent on phosphatidylinositol 3-kinase. The Ang-Tie2 system appears to have an autoregulatory feedback system that may be regulating the overall activity of the Tie2 system in both physiological and pathological conditions.
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