Platelets promote human macrophages-mediated macropinocytosis of Clostridioides difficile

BARBERO, ANGELA MARÍA; HERNÁNDEZ DEL PINO, RODRIGO EMANUEL; FUENTES, FEDERICO; BARRIONUEVO, PAULA; PASQUINELLI, VIRGINIA

Frontiers in Cellular and Infection Microbiology

Frontiers Media SA

Año: 2024 vol. 13

Clostridioides difficile is the main causative agent of hospital-acquireddiarrhea and the potentially lethal disease, C. difficile infection. Thecornerstone of the current therapy is the use of antibiotics, which is notfully effective. The molecular mechanisms, inflammatory conditions andhost-immune responses that could benefit the persistence or eliminationof C. difficile remain unclear. Macrophages perform different ways ofendocytosis as part of their immune surveillance functions and platelets,classically known for their coagulatory role, are also important modulators ofthe immune system. The aim of this study was to evaluate the endocytosisof vegetative C. difficile by human macrophages and the involvement ofplatelets in this process. Our results showed that both macrophages andplatelets interact with live and heat-killed C. difficile. Furthermore, plateletsform complexes with human monocytes in healthy donor’s fresh blood andthe presence of C. difficile increased these cell-cell interactions. Using flowcytometry and confocal microscopy, we show that macrophages caninternalize C. difficile and that platelets improve this uptake. By usinginhibitors of different endocytic pathways, we demonstrate thatmacropinocytosis is the route of entry of C. difficile into the cell. Takentogether, our findings are the first evidence for the internalization ofvegetative non-toxigenic and hypervirulent C. difficile by humanmacrophages and highlight the role of platelets in innate immunity duringC. difficile infection. Deciphering the crosstalk of C. difficile with immunecells could provide new tools for understanding the pathogenesis of C.difficile infection and for the development of host-directed therapies.