Abstract 453: The G Protein-coupled Estrogen Receptor GPER/GPR30 is a Potential Therapeutic Target for Cardiovascular Inflammation

Abstract

Abstract: Neutrophil extracellular traps (NETs), DNA-based structures that play an important role in pathogen killing/capture, are also thought to contribute to inflammatory disease and have been implicated in thrombosis. Pharmacological agents that can modulate the formation of extracellular traps are as-yet unknown. We hypothesized that targeting G protein-coupled receptors (GPCRs) may provide such agents and thereby could aid in treating inflammation in the cardiovascular system. Here, we investigated the role of the G protein-coupled estrogen receptor (GPER/GPR30), which has recently been shown to play a role in innate immune function (Cabas et al. J Immunol . 191: 4628-39 [2013]). Quantitative PCR revealed that GPER is highly expressed in human neutrophils isolated from healthy male and female donors. Fluorescent quantification of extracellular DNA using PicoGreen revealed that both selective (G-36) and general (raloxifene) antagonists of GPER, but not selective antagonists for the nuclear estrogen receptors ERa (MPP) or ERb (PHTPP) inhibited phorbol myristate acetate (PMA)-induced NET production by human neutrophils. These results were verified using high throughput imaging of fixed, SytoxGreen-stained neutrophils. The activity of GPER antagonists appeared to be independent of Erk1/2 signaling and reactive oxygen species (ROS) generation, pathways that are mediators of NET production. Immunocytochemistry revealed that G-36 treatment of neutrophils raises their concentration of cAMP, which can inhibit production of NETs. Taken together, our data suggest that GPER may be a novel therapeutic target for modulating NET production and inflammation in the cardiovascular system.