The importance of α1AMP-activated protein kinase (α1AMPK) in hemostatic dysfunctions induced by sepsis

Abstract

Sepsis is a pathological circumstance whose outcome is associated with organ dysfunction and death. Vascular hyperpermeability and hemostasis impairment both play a key role in the onset of organ failure. Our previous work highlighted the protective role of α1AMPK against sepsis-induced hyperpermeability. However, the impact of α1AMPK on hemostasis has never been investigated in this condition. This study aims to characterize the interaction of α1AMPK with hemostasis in sepsis. α1AMPK wild type (WT) and knockout (KO) mice were challenged with intraperitoneal injection of lipopolysaccharide (LPS) from Escherichia coli O55B5 (10 mg/kg) during 6 and 18 hours. Plasmatic markers of coagulation, NETosis and platelet activation were measured by ELISA. To identify cell type responsible for the dysregulation, same analyses were conducted on endothelial-, leucocyte- or platelet- specific α1AMPK knockout mouse models. Hemostasis was altered at 6 hours and 18 hours after LPS administration, in both α1AMPK WT and KO mice. Thrombin generation, reflected by thrombin-antithrombin complex formation, was significantly increased in α1AMPK KO mice compared to WT mice, after 18 hours of treatment with LPS. In contrast, fibrinolysis was more inhibited in α1AMPK KO than in WT mice, with a higher level of plasminogen activator inhibitor-1 measured at 6 and 18 hours, while tissue plasminogen activator was not different. This exacerbated procoagulant phenotype in α1AMPK KO mice was associated with an increase of sCD62P in plasma, reflecting an overactivation of platelets under septic conditions. Septic α1AMPK KO mice also showed an increase of Neutrophil Elastase and plasma DNA with no variation of MPO-DNA complexes, suggesting that NETosis was not altered but that exacerbated cellular damages occurred in these mice compared to WT animals. Platelet- and leucocyte- specific α1AMPK knockout mouse models did not recapitulate the phenotype observed in total α1AMPK knockout mice after LPS administration. However, endothelial specific α1AMPK knockout mice showed an increase of thrombin generation with a tendency to higher platelet activation. Altogether, these results demonstrate that α1AMPK plays a crucial role in the regulation of hemostasis disturbances during sepsis. While α1AMPK from platelets and leucocytes does not contribute to the septic damage, endothelialα1AMPK might be a brake for hemostatic dysregulation.