TY - JOUR

T1 - Cell-Free DNA Promotes Thrombin Autolysis and Generation of Thrombin-Derived C-Terminal Fragments

AU - Saravanan, Rathi

AU - Choong, Yeu Khai

AU - Lim, Chun Hwee

AU - Lim, Li Ming

AU - Petrlova, Jitka

AU - Schmidtchen, Artur

PY - 2021

Y1 - 2021

N2 - Cell-free DNA (cfDNA) is the major structural component of neutrophil extracellular traps (NETs), an innate immune response to infection. Antimicrobial proteins and peptides bound to cfDNA play a critical role in the bactericidal property of NETs. Recent studies have shown that NETs have procoagulant activity, wherein cfDNA triggers thrombin generation through activation of the intrinsic pathway of coagulation. We have recently shown that thrombin binds to NETs in vitro and consequently can alter the proteome of NETs. However, the effect of NETs on thrombin is still unknown. In this study, we report that DNA binding leads to thrombin autolysis and generation of multiple thrombin-derived C-terminal peptides (TCPs) in vitro. Employing a 25-residue prototypic TCP, GKY25 (GKYGFYTHVFRLKKWIQKVIDQFGE), we show that TCPs bind NETs, thus conferring mutual protection against nuclease and protease degradation. Together, our results demonstrate the complex interplay between coagulation, NET formation, and thrombin cleavage and identify a previously undisclosed mechanism for formation of TCPs.

AB - Cell-free DNA (cfDNA) is the major structural component of neutrophil extracellular traps (NETs), an innate immune response to infection. Antimicrobial proteins and peptides bound to cfDNA play a critical role in the bactericidal property of NETs. Recent studies have shown that NETs have procoagulant activity, wherein cfDNA triggers thrombin generation through activation of the intrinsic pathway of coagulation. We have recently shown that thrombin binds to NETs in vitro and consequently can alter the proteome of NETs. However, the effect of NETs on thrombin is still unknown. In this study, we report that DNA binding leads to thrombin autolysis and generation of multiple thrombin-derived C-terminal peptides (TCPs) in vitro. Employing a 25-residue prototypic TCP, GKY25 (GKYGFYTHVFRLKKWIQKVIDQFGE), we show that TCPs bind NETs, thus conferring mutual protection against nuclease and protease degradation. Together, our results demonstrate the complex interplay between coagulation, NET formation, and thrombin cleavage and identify a previously undisclosed mechanism for formation of TCPs.

KW - antimicrobial peptides

KW - cell-free DNA (cfDNA)

KW - coagulation

KW - host defense peptides

KW - molecular innate immunity

KW - NETs (neutrophil extracellular traps)

KW - thrombin

UR - http://www.scopus.com/inward/record.url?scp=85102339869&partnerID=8YFLogxK

U2 - 10.3389/fimmu.2021.593020

DO - 10.3389/fimmu.2021.593020

M3 - Journal article

C2 - 33717072

AN - SCOPUS:85102339869

VL - 12

JO - Frontiers in Immunology

JF - Frontiers in Immunology

SN - 1664-3224

M1 - 593020

ER -