Abstract P430: Angiotensin-(1-7) Induces A Decrease In Proinflammatory Genes Expression Through A Mas Receptor-Mediated Translocation To Brainstem Nuclei Of Spontaneously Hypertensive Rats

Abstract

Mas receptor (MasR) displays differential trafficking in brainstem neurons from spontaneously hypertensive rats (SHRs): the fraction of dynamin-mediated internalized MasRs into early endosomes was larger and the fraction of MasRs recycled back to the plasma membrane was smaller in SHR than in Wistar neurons. Surprisingly, in SHR neurons but not in Wistar neurons, Ang-(1-7) induced MasR translocation to the nucleus. Our aim was to investigate the biological response elicited by MasR in the nucleus and whether MasR translocation was due to interaction with other receptors. We evaluated: 1) nitric oxide (NO) generation by DAF (diaminofluorescein) fluorescence; 2) interleukin (IL) 6, IL-1β, cyclooxygenase 2 (COX2) and NFkB expression by real time PCR; and 3) MasR interaction with AT1R and the dopamine type 2 receptor (D2R) by proximity ligation assay in brainstem neuronal primary cultures from Wistar and SHR rats incubated in the presence or absence of Ang-(1-7) or Ang-(1-7) + dynasore (DYN) (dynamin inhibitor) or Ang-(1-7) + A779 (MasR antagonist) during 30 min. Ang-(1-7) (100 nM) induced a decrease in the pro-inflammatory factors IL-6, IL-1β, COX2 and NFkB expression in brainstem neurons from Wistar and SHR rats which was blocked by A779, suggesting a MasR-mediated response. The effect of Ang-(1-7) was prevented when MasR internalization was prevented by DYN only in SHRs neurons but not in Wistar neurons, suggesting that the effect of Ang-(1-7) in SHR neurons is mediated by MasR translocation to the nucleus. Treatment of neurons with Ang-(1-7) induced an increase in NO in the nucleus of SHR but not of Wistar neurons and this effect was prevented by DYN and A779, suggesting that the Ang-(1-7)-induced NO production in the nucleus was due to MasR translocation to this compartment. MasR stimulation with Ang-(1-7) induced an increase in MasR-D2R heteromerization in SHR but not in Wistar neurons, and no change in MasR-AT1R heteromerization. Ou study showed that MasR translocation to the nucleus resulted in a reduction in pro-inflammatory genes expression and an increase in NO generation in SHR neurons. A fraction of MasR was translocated through the interaction with D2Rs, suggesting that this heteomer may be involved in the anti-inflammatory responses elicited by Mas translocation to the nucleus.