Immunity against Moraxella catarrhalis requires guanylate‐binding proteins and caspase‐11‐NLRP3 inflammasomes
Daniel Enosi Tuipulotu, Shouya Feng, Abhimanu Pandey, Anyang Zhao, Chinh Ngo, Anukriti Mathur, Jiwon Lee, Cheng Shen, Daniel Fox, Yansong Xue, Callum Kay, Max Kirkby, Jordan Lo Pilato, Nadeem O. Kaakoush, Daryl Webb, Melanie Rug, Avril A. B. Robertson, Melkamu B. Tessema, Stanley Pang, Daniel Degrandi, Klaus Pfeffer, Daria Augustyniak, Antje Blumenthal, Lisa A. Miosge, Anne Brüstle, Masahiro Yamamoto, Patrick C. Reading, Gaétan Burgio, Si Ming Man
Abstract
Moraxella catarrhalis is an important human respiratory pathogen and a major causative agent of otitis media and chronic obstructive pulmonary disease. Toll-like receptors contribute to, but cannot fully account for, the complexity of the immune response seen in M. catarrhalis infection. Using primary mouse bone marrow-derived macrophages to examine the host response to M. catarrhalis infection, our global transcriptomic and targeted cytokine analyses revealed activation of immune signalling pathways by both membrane-bound and cytosolic pattern-recognition receptors. We show that M. catarrhalis and its outer membrane vesicles or lipooligosaccharide (LOS) can activate the cytosolic innate immune sensor caspase-4/11, gasdermin-D-dependent pyroptosis, and the NLRP3 inflammasome in human and mouse macrophages. This pathway is initiated by type I interferon signalling and guanylate-binding proteins (GBPs). We also show that inflammasomes and GBPs, particularly GBP2, are required for the host defence against M. catarrhalis in mice. Overall, our results reveal an essential role for the interferon-inflammasome axis in cytosolic recognition and immunity against M. catarrhalis, providing new molecular targets that may be used to mitigate pathological inflammation triggered by this pathogen.