Abstract 339: Ang-(1-7) Counteracts Ang II in Regulating Cerebrovascular Endothelial Cell Function and Gene Expression

Abstract

Cerebrovascular endothelial cells (cECs) play an important role in maintaining the health of cerebral vasculatures. In this study, we investigated the role of angiotensin (Ang)-(1-7) in counteracting Ang II-induced effects on cECs. The 3rd-5th passages of brain microvascular endothelial cells (BMECs, Cell system) cultured in CSC complete medium (Cell system) were used for this study. BMECs were treated with Ang II (100 nM), Ang-(1-7) (100 nM) and A-779 (100 nM, Mas receptor antagonist). After treatment for 24 hrs, cell apoptosis was determined by flow cytometery. BMEC tube formation ability was determined using a commercial kit. The levels of tumor necrosis factor- α (TNF-α), monocyte chemoattractant protein 1 (MCP-1) and interleukin (IL-8) in the cell culture supernatant were determined by ELISA. Gene expressions of NFκB, inhibitor of kappa B (IκB) were determined by western blot. To verify the involvement of NFκB pathway, the inhibitor (BAY11-7082, 10 uM) was applied. We found (Figure): 1) Treatment with Ang-(1-7) decreased Ang II-induced apoptosis (22 ± 1.5% vs. 14 ± 1.2%, Ang II vs. Ang II + Ang-(1-7), P<0.01). 2) Ang-(1-7) improved BMEC tube formation ability compromised by Ang II, which was accompanied by up-regulation of IκB expression, the down-regulation of NFκB, and decrease of TNF-α, MCP-1 and IL-8 production of BMECs. 3) These effects of Ang-(1-7) were totally abolished by A-779 and partially blocked by BAY 11-7082. In conclusion, Ang-(1-7)/Mas activation counteracts Ang II-induced BMEC apoptosis and dysfunction, partially via the NFκB dependent inflammation pathway.