Sex hormone regulation of neutrophil function is dependent on activation state

Cellular physiology is critically modulated by hormones. Our understanding of their effect on neutrophil, most abundant leukocytes, function is limited. The goal of this study was to characterize the molecular mechanisms that underline hormones' modulation of neutrophil effector functions and the effect of activation state on this modulation. Neutrophils were isolated from young adult (2.5-6months of age) male and female mice with or without lipopolysaccharide (LPS) injection (primed state). Isolated neutrophils (primed and non-primed (healthy)) were incubated with estradiol (E2) or dihydrotestosterone (DHT), and cellular changes were assessed using mass spectrometry and functional assays. Our results showed that the effect of hormones on neutrophil function is sex specific. For neutrophils isolated from female mice, both E2 and DHT decreased degranulation, increased phagocytosis, with no effect on NETosis regardless of activation state. E2 increased the pentose phosphate pathway (PPP) and migration of neutrophils in an activation-dependent manner. DHT increased glycolysis and PPP regardless of activation. In neutrophils isolated from male mice, DHT and E2 decreased degranulation in primed cells only. DHT increased phagocytosis and glycolysis in primed cells while E2 decreased glycolysis and PPP in healthy cells. E2 also increased phagocytosis in healthy cells while decreasing it in primed. DHT increased migration of healthy cells with no effect on primed. These results showed that hormone modulation of female neutrophil function is independent of activation state, while its effect on male derived neutrophils is activation dependent. We propose that these differences contribute to the sex differences observed in inflammatory responses.