Angiopoietin-1: Can be produced by endothelial cells and act in an autocrine agonistic manner?

The source of Ang1 is controversial. Although some people think that human endothelial cells can produce Ang1, more believe that endothelial cells produce Ang2 but not Ang1. However, in our recent study on endothelial cells and angiogenesis, we find that endothelial cells do produce Ang1.

This study aims to prove that endothelial cells can produce Ang1 and explore what manner does Ang1 act in.

Immunohistochemistry, western blotting and reverse transcription PCR were used to prove if human dermal microvascular endothelial cells, human brain microvascular endothelial cells and human umbilical vein endothelial cells produce Ang1. In order to explore Ang1's act manner, Ang1 expression of human dermal microvascular endothelial cells pre-treated by propranolol IC50 was detected by western blotting.

Immunohistochemistry, western blotting and reverse transcription PCR showed that human dermal microvascular endothelial cells, human brain microvascular endothelial cells and human umbilical vein endothelial cells all expressed Ang1, and propranolol significantly inhibited Ang1 expression of human dermal microvascular endothelial cells.

Endothelial cells can also produce Ang1. In addition, endogenous Ang1 may be an autocrine agonistic regulator, participating in endothelial cells angiogenesis process.