Abstract
Sepsis, a complex clinical syndrome resulting from a serious infection, is a major healthcare problem associated with high mortality. Sex-related differences in the immune response to sepsis have been proposed but the mechanism is still unknown. Purinergic signaling is a sex-specific regulatory mechanism in immune cell physiology. Our studies have shown that blocking the ADP-receptor P2Y(12) but not P2Y(1) receptor was protective in male mice during sepsis, but not female. We now hypothesize that there are sex-related differences in modulating P2Y(12) or P2Y(1) signaling pathways during sepsis. Male and female wild-type (WT), P2Y(12) knock-out (KO), and P2Y(1) KO mice underwent sham surgery or cecal ligation and puncture (CLP) to induce sepsis. The P2Y(12) antagonist ticagrelor or the P2Y(1) antagonist MRS2279 were administered intra-peritoneally after surgery to septic male and female mice. Blood, lungs and kidneys were collected 24 hours post-surgery. Sepsis-induced changes in platelet activation, secretion and platelet interaction with immune cells were measured by flow cytometry. Neutrophil infiltration in the lung and kidney was determined by a myeloperoxidase (MPO) colorimetric assay kit. Sepsis-induced platelet activation, secretion and aggregate formation were reduced in male CLP P2Y(12) KO and in female CLP P2Y(1) KO mice compared with their CLP WT counterpart. Sepsis-induced MPO activity was reduced in male CLP P2Y(12) KO and CLP P2Y(1) KO female mice. CLP males treated with ticagrelor or MRS2279 showed a decrease in sepsis-induced MPO levels in lung and kidneys, aggregate formation, and platelet activation as compared to untreated male CLP mice. There were no differences in platelet activation, aggregate formation, and neutrophil infiltration in lung and kidney between female CLP mice and female CLP mice treated with ticagrelor or MRS2279. In human T lymphocytes, blocking P2Y(1) or P2Y(12) alters cell growth and secretion in vitro in a sex-dependent manner, supporting the data obtained in mice. In conclusion, targeting purinergic signaling represents a promising therapy for sepsis but drug targeting purinergic signaling is sex-specific and needs to be investigated to determine sex-related targeted therapies in sepsis.