Hypoxia and vascular endothelial growth factor acutely up-regulate angiopoietin-1 and Tie2 mRNA in bovine retinal pericytes

Yoon Shin Park, Nan Hee Kim, Inho Jo

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80 Scopus citations


The angiopoietin/Tie2 system is a predominant regulator of vascular development. This vascular development appears to be controlled and completed by the coordinated actions of two vascular cells, endothelial cells and their surrounding supporting cells, smooth muscle cells, or pericytes. The role of the angiopoietin/Tie2 system has been studied, but these studies are limited mostly to endothelial cells. In this study, using bovine retinal pericytes (BRP), we investigated the effect of two known angiogenic stimuli, hypoxia and vascular endothelial growth factor (VEGF) treatment, on the regulation of the angiopoietin/Tie2 system. Hypoxia (2% O2 concentration) was acquired by a hypoxia chamber. Both hypoxia and VEGF (10 ng/ml) treatment significantly increased angiopoietin-1 (Ang1) mRNA expression. This marked augmentation occurred acutely (maximal increase at 2 h) and subsequently decreased. In contrast, angiopoietin-2 (Ang2) mRNA expression was unaltered in BRP upon both treatment. Significant up-regulation of Tie2 mRNA expression was found and lasted up to 12 h. However, using bovine aortic endothelial cells (BAEC), we found that only Ang2 expression, but neither Ang1 nor Tie2, responded to these two angiogenic stimuli, which was consistent with many previous reports. In conclusion, our data suggest that both hypoxia and VEGF treatment differentially regulate the angiopoietin/Tie2 system in the two vascular cells and that, particularly in BRP, the regulation of Ang1, but not Ang2, and Tie2 expression may play an important role in vascular development.

Original languageEnglish
Pages (from-to)125-131
Number of pages7
JournalMicrovascular Research
Issue number2
StatePublished - Mar 2003

Bibliographical note

Funding Information:
This work was supported in part by a Korea National Institute of Health intramural research grant (334-6113-211-207-00) and by a Science Research Center grant from the Korea Science and Engineering Foundation (KOSEF) to the Nitric Oxide Radical Toxicology Research Center (NORTReC) to Dr. Inho Jo and by a Korea Research Foundation (2001-003-F00070) grant from the Ministry of Education and Human Resources Development to Dr. Nan Hee Kim. We thank Ms. Jooyoung Lee for secretarial assistance.


  • Angiopoietin
  • Bovine aortic endothelial cell
  • Bovine retinal pericyte
  • Hypoxia
  • Tie2
  • Vascular endothelial cell growth factor


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