Neutrophil extracellular trap stabilization leads to improved outcomes in murine models of sepsis

Abstract

Word Count: 204 Text Word Count: 4622 Figure Count: 7 Reference Count: 81 AbstractSepsis is characterized by multi-organ system dysfunction that occurs due to infection. It is associated with unacceptably high morbidity and mortality and in need of improved therapeutic intervention. Neutrophils play a crucial role in sepsis, releasing neutrophil extracellular traps (NETs) composed of DNA complexed with histones and toxic antimicrobial proteins that ensnare pathogens but also damage host tissues. At presentation, patients likely have a significant NET burden contributing to the multi-organ damage. Therefore, interventions that prevent NET release would likely be ineffective at preventing NET-based injury. Treatments that enhance NET degradation may liberate captured bacteria and toxic NET degradation products (NDPs) and therefore be of limited therapeutic benefit. We propose that interventions that stabilize NETs and sequester NDPs may be protective in sepsis. Platelet factor 4 (PF4, CXCL4) a platelet-associated chemokine, binds and compacts NETs, increasing their resistance to deoxyribonuclease I. A monoclonal antibody, KKO, which binds to PF4-NET complexes, further enhances this resistance.We now show that PF4 increases NET-mediated bacterial capture in vitro, reduces the release of NDPs, and improves outcome in murine models of sepsis. An Fc-modified KKO further enhances deoxyribonuclease resistance, decreases NDP release, and increases survival in these models, supporting a novel NET-targeting approach to improve outcomes in sepsis.

Targeting Biological Polyanions in Blood: Strategies toward the Design of Therapeutics

“…A study utilizing PF4, a cationic protein released by platelets, demonstrated PF4 ability to bind to NETs and compact its structure. The neutralized NETs retained the ability to capture bacteria and improved the outcomes of sepsis in mouse models . In addition, heparin can be seen to bind to NET histones and prevent NET induced platelet aggregation .…”

“…The neutralized NETs retained the ability to capture bacteria and improved the outcomes of sepsis in mouse models. 333 In addition, heparin can be seen to bind to NET histones and prevent NET induced platelet aggregation. 255 Treatment of human septic plasma samples with protamine sulfate ex vivo has shown to decrease thrombin generation.…”