Interaction Between the Angiotensin-(1–7) Mas Receptor and the Dopamine D2 Receptor

Abstract

Supplemental Digital Content is available in the text. Ang (angiotensin) 1–7 MasR (Mas receptor) and D2R (dopamine D2 receptor) stimulation is coupled to anti-inflammatory responses. In the present work, we investigated the hypothesis that the anti-inflammatory action mediated by both receptors results from MasR-D2R heteromerization. Human monocyte (THP-1) cells differentiated to macrophages and exposed to lipopolysaccharide were employed. Ang (1–7) and the D2R agonist SUM (sumanirole) induced a decrease in proinflammatory IL (interleukin) 6 release in human macrophages exposed to a proinflammatory stimulus. The Ang (1–7)–induced decrease in IL-6 was blocked by the D2R antagonist. Conversely, the SUM induced decrease in IL-6 was prevented by the MasR antagonist and when MasR expression was downregulated, suggesting MasR-D2R interaction. Co-immunoprecipitation assay in THP-1 cells and in human monocyte differentiated macrophages from peripheral blood mononuclear cells confirmed MasR-D2R interaction. To avoid the influence from other receptors, MasR-D2R interaction was characterized in transfected human embryonic kidney 293T cells. Fluorescence resonance energy transfer analysis showed that MasR and D2R formed a constitutive heteromer, which was not modified by their agonists. Ang (1–7) and dopamine stimulated ERK (extracellular signal-regulated kinase) 1/2 and Akt (protein kinase B) phosphorylation only in cells expressing MasR-D2R heteromers, but not in cells expressing each receptor alone. Ang (1–7)–stimulated ERK1/2 and Akt phosphorylation was prevented by D2R blockade while the effect of dopamine was prevented by MasR blockade, reinforcing the fact that MasR-D2R heteromers are involved in ERK1/2 and Akt activation induced by their agonists. Our findings provide new evidence regarding the mechanisms underlying the cross-talk between the Ang (1–7)/MasR axis and the dopaminergic system in response to a proinflammatory process.