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Communication Dans Un Congrès Année : 2023

Development of trained immunity and activation of inflammasomes are promising strategies to combat Staphylococcus aureus infection

Yann Le Gouar
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  • PersonId : 1203674
Jordane Ossemond
  • Fonction : Auteur
  • PersonId : 1203233
Gwénaël Jan
Eric Guédon
Yves Le Loir

Résumé

Introduction and objectives Staphylococcus aureus causes life-threatening diseases such as pneumonia and osteomyelitis. Trained immunity (TI) enhances the immune response to subsequent unrelated challenges through epigenetic reprogramming of transcriptional pathways and alteration of cell metabolism [1]. Moreover, pathogens activate inflammasomes that trigger protease activation, particularly caspase-1. Caspase-1 proteolytically matures and promotes the secretion of mature IL-1β and IL-18 [2]. Our objectives include investigating the development of TI in non-immune cells, examining interleukin production and epigenetic marks, exploring the involvement of reactive oxygen species (ROS), and comprehending the role of inflammasomes and their effector, caspase-1, in the context of S. aureus infection. Materials and methods We developed an in vitro TI model using human osteoblast-like MG-63 and epithelial lung A549 cells [3]. Techniques employed included microbiology methods of bacterial cultivation, enzyme-linked immunosorbent assay (ELISA), microscopic analysis, and flow cytometry. We investigated the involvement of ROS using the scavenger N-acetylcysteine (NAC) [4]. The role of inflammasomes and Caspase-1 was examined by a comparison of MG-63 cells and caspase-1 knock-out CASP1−/−MG-63 cells that were generated via CRISPR-Cas9 technology [5]. The role of bacterial effectors were analyzed using deletion and complemented phenol-soluble modulins (PSMs) mutants. Results, discussion and conclusion β-glucan training of MG-63 and A549 cells increased IL-6/IL-8 production upon a stimulation with S. aureus. Interleukin production positively correlated with Histone 3 acetylation at lysine 27 (H3K27), indicating epigenetic reprogramming. NAC addition, prior to β-glucan training before S. aureus infection, inhibited IL-6/IL-8 production, thereby supporting the involvement of ROS in the induction of TI. Cell exposure to bacterium with probiotic properties, Lactococcus lactis, before S. aureus infection also elevated IL-6/IL-8 production, accompanied by H3K27 acetylation, suggesting its ability to induce TI [3]. Infected MG-63 cells activated inflammasomes, releasing mature IL-1β, while CASP1−/−MG-63 cells lacked this activation. PSMs were identified as key contributors to inflammasome-related IL-1β production using S. aureus mutants. Additionally, caspase-1 deficiency impaired cell defense, resulting in decreased bacterial clearance in CASP1−/−MG-63 cells [5]. Our results demonstrate two host strategies against S. aureus infection with therapeutic potential and reveal the involvement of non-immune cells in defense response beyond their structural functions and tissue homeostasis maintenance.
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hal-04234405 , version 1 (10-10-2023)

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Paternité - Pas d'utilisation commerciale - Pas de modification

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  • HAL Id : hal-04234405 , version 1

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Emmanuel Chaumond, Elma Lima Leite, Sandrine Péron, Nathalie Daniel, Yann Le Gouar, et al.. Development of trained immunity and activation of inflammasomes are promising strategies to combat Staphylococcus aureus infection. 18e congrès national de la SFM « Un monde à explorer », Société Française de Microbiologie (SFM), Oct 2023, Rennes, France. ⟨hal-04234405⟩
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