Manchester Metropolitan University's Research Repository

    Neutrophils Protect Against Staphylococcus aureus Endocarditis Progression Independent of Extracellular Trap Release

    Meyers, Severien, Lox, Marleen, Kraisin, Sirima, Liesenborghs, Laurens, Martens, Caroline P, Frederix, Liesbeth, Van Bruggen, Stijn, Crescente, Marilena ORCID logoORCID: https://orcid.org/0000-0003-3164-512X, Missiakas, Dominique, Baatsen, Pieter, Vanassche, Thomas, Verhamme, Peter and Martinod, Kimberly (2023) Neutrophils Protect Against Staphylococcus aureus Endocarditis Progression Independent of Extracellular Trap Release. Arteriosclerosis, Thrombosis and Vascular Biology, 43 (2). pp. 267-285. ISSN 1079-5642

    Published Version
    Available under License Creative Commons Attribution Non-commercial No Derivatives.

    Download (9MB) | Preview


    Background: Infective endocarditis (IE) is characterized by an infected thrombus at the heart valves. How bacteria bypass the immune system and cause these thrombi remains unclear. Neutrophils releasing NETs (neutrophil extracellular traps) lie at this interface between host defense and coagulation. We aimed to determine the role of NETs in IE immunothrombosis. Methods: We used a murine model of Staphylococcus aureus endocarditis in which IE is provoked on inflamed heart valves and characterized IE thrombus content by immunostaining identifying NETs. Antibody-mediated neutrophil depletion and neutrophil-selective PAD4 (peptidylarginine deiminase 4)-knockout mice were used to clarify the role of neutrophils and NETs, respectively. S. aureus mutants deficient in key virulence factors related to immunothrombosis (nucleases or staphylocoagulases) were investigated. Results: Neutrophils releasing NETs were present in infected thrombi and within cellular infiltrates in the surrounding vasculature. Neutrophil depletion increased occurrence of IE, whereas neutrophil-selective impairment of NET formation did not alter IE occurrence. Absence of S. aureus nuclease, which degrades NETs, did not affect endocarditis outcome. In contrast, absence of staphylocoagulases (coagulase and von Willebrand factor binding protein) led to improved survival, decreased bacteremia, smaller infiltrates, and decreased tissue destruction. Significantly more NETs were present in these vegetations, which correlated with decreased bacteria and cell death in the adjacent vascular wall. Conclusions: Neutrophils protect against IE independent of NET release. Absence of S. aureus coagulases, but not nucleases, reduced IE severity and increased NET levels. Staphylocoagulase-induced fibrin likely hampers NETs from constraining infection and the resultant tissue damage, a hallmark of valve destruction in IE.

    Impact and Reach


    Activity Overview
    6 month trend
    6 month trend

    Additional statistics for this dataset are available via IRStats2.


    Repository staff only

    Edit record Edit record