Factor XIII-A Transglutaminase Contributes to Neutrophil Extracellular Trap (NET)-mediated Fibrin(ogen) Network Formation and Crosslinking

expression in adipose tissue, blood, and bone marrow neutrophils. mRNA expression and protein production were confirmed in isolated neutrophils where expression was comparable to that of macrophages and monocytes. FXIII-A was externalized and active as a transglutaminase and colocalized with NET markers during NETosis. FXIII-A transglutaminase activity promoted NET-fibrin(ogen) interaction and entrapment of neutrophils within fibrin(ogen) matrix. Soluble fibrinogen or fibrin(ogen) network did not induce NETosis.This study identifies neutrophils as a source of FXIII-A and suggests its role in stabilizing NET-fibrin(ogen) matrix structures.