Angiotensin II and Arachidonyl‐2′‐chloroethylamide effects on Nuclear factor kappa B and Prostaglandin E2

Abstract

Objective : To determine the effect of Angiotensin (Ang) II and Arachidonyl-2′-chloroethylamide (ACEA) on nuclear factor kappa B (NFkB) activation and prostaglandin E2 (PGE2) production in rat astrocytes. Background :Neuroinflammation is a hallmark of numerous diseases including neurogenic hypertension. NFkB and PGE2 have been shown to mediate proinflammatory processes. We investigated the effect of Ang II and ACEA, a selective agonist of the CB1R, on NFkB phosphorylation and PGE2 production in astrocytes. Further, we investigated whether differences in NFkB phosphorylation and PGE2 production were observed in Wistar astrocytes compared to astrocytes isolated from the spontaneously hypertensive rat (SHR). Methods Brainstem and cerebellum astrocytes were prepared from 2-3day old rat pups. Quiescent cells were treated with 100nM Ang II or 10nM ACEA for varying time intervals. Phosphorylated (p)NFkB protein levels were measured by western blotting and PGE2 levels by ELISA. Results Ang II and ACEA had contrasting effects on NFkB phosphorylation and PGE2 production. ACEA showed significant NFkB activation predominantly in Wistar astrocytes whereas Ang II showed significant NFkB activation mainly in SHR astrocytes at similar time points. Ang II increased PGE2 production with higher levels produced in SHR compared to Wistar astrocytes. ACEA both increased and decreased PGE2 production depending on the brain region. Conclusion These results provide insight on early molecular changes in astrocytes from Wistar as compared to prehypertensive SHRs. We demonstrated that both Ang II and ACEA induced NFkB activation in astrocytes. However, Ang II potently induced PGE2 production compared to ACEA. It is plausible that ACEA could potentially counter these Ang II effects on PGE2 production. Further studies are required to understand these early molecular changes in SHRs, and the molecular mechanisms by which both Ang II and ACEA elicit their effects.