Blocking purinergic signaling alters platelet and macrophage crosstalk and phagocytic ability in the peritoneal cavity during intra-abdominal sepsis

Abstract

Intra-abdominal sepsis is a life-threatening complex syndrome caused by dysregulation of the host response to infection and is one of the major complications of intra-abdominal surgery. To date, only supportive therapies such as ventilation support, antibiotics and organ replacement are available. However, an increase in antibiotic resistance and the invasiveness of organ transplant has necessitated therapies targeting pathophysiological mechanisms. Platelets, which express the purinergic receptors P2Y1 and P2Y12, mediate macrophage polarization and secretion of pro-inflammatory markers contributing to tissue injury during sepsis. Previously, our group has shown that blocking purinergic signaling through P2Y1 and P2Y12 antagonism significantly lowered inflammatory cytokine levels and improved survival in a murine model of sepsis in a sex specific manner. We hypothesize that the inhibition of P2Y1 and P2Y12 signaling pathways improves the sex-specific outcomes of intra-abdominal sepsis by modulating the crosstalk between platelets and macrophages. Male and female mice underwent sham surgery or cecal ligation and puncture (CLP) to induce sepsis followed by intraperitoneal administration of ticagrelor (P2Y12 antagonist) or MRS2279 (P2Y1 antagonist). The peritoneal cavity fluid (PCF) was collected 4 and 24 hours post-surgery and analyzed. At 4 hours post-surgery, PCF macrophages exhibited increased bacterial phagocytosis from ticagrelor and MRS2279 treated groups in female mice only compared to CLP group. At 24 hours post-CLP surgery, platelet counts did not change but soluble p-selectin and TBX-2 levels were significantly decreased in male groups treated with either ticagrelor or MRS2279, compared to controls. In contrast, soluble p-selectin and TBX-2 levels did not change in female samples.Thus, we conclude that pharmacologically blocking P2Y1 and P2Y12 receptors can enhance the ex-vivo phagocytic activity of macrophages in a sex-related manner, and overall modulate platelet secretion and influence macrophages’ recruitment and activation in the PC during sepsis. National Institute of Health AI156627-01 to EL This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.