EEF2-inactivating toxins engage the NLRP1 inflammasome and promote epithelial barrier disruption

• Main Authors: Pinilla, Miriam, Mazars, Raoul, Vergé, Romain, Gorse, Leana, Paradis, Margaux, Suire, Bastien, Santoni, Karin, Robinson, Kim Samirah, Toh, Gee Ann, Prouvensier, Laure, Leon-Icaza, Stephen Adonai, Hessel, Audrey, Péricat, David, Murris, Marlène, Guet-Revillet, Hélène, Henras, Anthony, Buyck, Julien, Ravet, Emmanuel, Zhong, Franklin, Cougoule, Céline, Planès, Rémi, Meunier, Etienne
• Other Authors: Lee Kong Chian School of Medicine (LKCMedicine)
• Format: Article
• Language: English
• Published: 2023
• Subjects: Science::Medicine; Elongation Factor 2; Inflammasome
• Online Access: https://hdl.handle.net/10356/171557
• Institution: Nanyang Technological University

Human airway and corneal epithelial cells, which are critically altered during chronic infections mediated by Pseudomonas aeruginosa, specifically express the inflammasome sensor NLRP1. Here, together with a companion study, we report that the NLRP1 inflammasome detects exotoxin A (EXOA), a ribotoxin released by P. aeruginosa type 2 secretion system (T2SS), during chronic infection. Mechanistically, EXOA-driven eukaryotic elongation factor 2 (EEF2) ribosylation and covalent inactivation promote ribotoxic stress and subsequent NLRP1 inflammasome activation, a process shared with other EEF2-inactivating toxins, diphtheria toxin and cholix toxin. Biochemically, irreversible EEF2 inactivation triggers ribosome stress-associated kinases ZAKα- and P38-dependent NLRP1 phosphorylation and subsequent proteasome-driven functional degradation. Finally, cystic fibrosis cells from patients exhibit exacerbated P38 activity and hypersensitivity to EXOA-induced ribotoxic stress-dependent NLRP1 inflammasome activation, a process inhibited by the use of ZAKα inhibitors. Altogether, our results show the importance of P. aeruginosa virulence factor EXOA at promoting NLRP1-dependent epithelial damage and identify ZAKα as a critical sensor of virulence-inactivated EEF2.