Neutrophil extracellular trap-microparticle complexes enhance thrombin generation via the intrinsic pathway of coagulation in mice

Abstract

Abdominal sepsis is associated with dysfunctional hemostasis. Thrombin generation (TG) is a rate-limiting step in systemic coagulation. Neutrophils can expell neutrophil extracellular traps (NETs) and/or microparticles (MPs) although their role in pathological coagulation remains elusive. Cecal ligation and puncture (CLP)-induced TG in vivo was reflected by a reduced capacity of plasma from septic animals to generate thrombin. Depletion of neutrophils increased TG in plasma from CLP mice. Sepsis was associated with increased histone 3 citrullination in neutrophils and plasma levels of cell-free DNA and DNA-histone complexes and administration of DNAse not only eliminated NET formation but also elevated TG in sepsis. Isolated NETs increased TG and co-incubation with DNAse abolished NET-induced formation of thrombin. TG triggered by NETs was inhibited by blocking factor XII and abolished in factor XII-deficient plasma but intact in factor VII-deficient plasma. Activation of neutrophils simultaneously generated large amount of neutrophil-derived MPs, which were found to bind to NETs via histone-phosphatidylserine interactions. These findings show for the first time that NETs and MPs physically interact, and that NETs might constitute a functional assembly platform for MPs. We conclude that NET-MP complexes induce TG via the intrinsic pathway of coagulation and that neutrophil-derived MPs play a key role in NET-dependent coagulation.

Neutrophil extracellular trap‐microparticle complexes trigger neutrophil recruitment via high‐mobility group protein 1 (HMGB1)‐toll‐like receptors(TLR2)/TLR4 signalling

“…We next asked if MPs attached to NETs play a role in NET‐induced inflammation. As shown recently (Wang et al, ), PMA stimulation of neutrophils triggers the formation of NETs containing numerous MPs (Figure a,c). Co‐incubation of neutrophils with calpain and caspase inhibitors resulted in the formation of NETs with markedly less MPs (Figure b,d).…”

“…NETs are known to be loaded with numerous different nuclear, cytoplasmatic, and granular proteins, which contribute to the biological effects of NETs (Brinkmann et al, ). We have recently demonstrated that MPs formed during neutrophil activation can bind to NETs and form NET‐MP complexes, which are important for thrombin generation in sepsis (Wang et al, ). In the present study, we wanted to define the role of NET‐MP aggregates in the regulation of neutrophil recruitment in acute inflammation.…”

“…(a) n = 5 different animals for each group, (b) n = 5 samples run in triplicate. *P < .05, significantly different from 0-hr vehicle and # P < .05, significantly different from vehicle demonstrated that MPs formed during neutrophil activation can bind to NETs and form NET-MP complexes, which are important for thrombin generation in sepsis(Wang et al, 2018). In the present study, we wanted to define the role of NET-MP aggregates in the regulation of neutrophil recruitment in acute inflammation.…”

c-Abl kinase regulates neutrophil extracellular trap formation, inflammation, and tissue damage in severe acute pancreatitis

“…Thus, c‐Abl kinase‐dependent generation of ROS might be involved in TNF‐α‐induced formation of NETs in neutrophils. Although neutrophil‐derived NETs are recognized for their important role in the innate immune system by trapping microbes facilitating microbiological clearance, several studies have shown that excessive formation of NETs is known to cause tissue injury and organ failure in infectious conditions . In this context, it is interesting to note that accumulating reports demonstrate that Abl kinase function is subverted by numerous bacterial and viral pathogens to achieve entry, motility, release, and survival in mammalian host cells .…”

Extracellular vesicles and microvascular pathology: Decoding the active dialogue

“…Tumor apoptotic vesicles may enhance the risk of thrombotic events in cancer patients undergoing chemotherapy by mechanisms depending notably on phosphatidylserine, TF expression, Factor VII and the prothrombinase complex . EV at large play an important role in the hypercoagulable state of cancer patients, and they have the potential to become involved in complexes with neutrophil extracellular traps, which lead to enhanced thrombin generation …”