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Dikshit N, Kale SD, Khameneh HJ, Balamuralidhar V, Tang CY, Kumar P, Lim TP, Tan TT, Kwa AL, Mortellaro A, Sukumaran B. NLRP3 inflammasome pathway has a critical role in the host immunity against clinically relevant Acinetobacter baumannii pulmonary infection. Mucosal Immunol 2018; 11:257-272. [PMID: 28612844 DOI: 10.1038/mi.2017.50] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2017] [Accepted: 04/15/2017] [Indexed: 02/04/2023]
Abstract
The opportunistic Gram-negative bacterium Acinetobacter baumannii (AB) is a leading cause of life-threatening nosocomial pneumonia. Outbreaks of multidrug resistant (MDR)-AB belonging to international clones (ICs) I and II with limited treatment options are major global health threats. However, the pathogenesis mechanisms of various AB clonal groups are understudied. Although inflammation-associated interleukin-1β (IL-1β) levels and IL-1 receptor antagonist polymorphisms were previously implicated in MDR-AB-related pneumonia in patients, whether inflammasomes has any role in the host defense and/or pathogenesis of clinically relevant A. baumannii infection is unknown. Using a sublethal mouse pneumonia model, we demonstrate that an extensively drug-resistant clinical isolate (ICII) of A. baumannii exhibits reduced/delayed early pulmonary neutrophil recruitment, higher lung persistence, and, most importantly, elicits enhanced IL-1β/IL-18 production and lung damage through NLRP3 inflammasome, in comparison with A. baumannii-type strain. A. baumannii infection-induced IL-1β/IL-18 production is entirely dependent on NLRP3-ASC-caspase-1/caspase-11 pathway. Using Nlrp3-/- mice infection models, we further show that while NLRP3 inflammasome pathway contributes to host defense against A. baumannii clinical isolate, it is dispensable for protection against A. baumannii-type strain. Our study reveals a novel differential role for NLRP3 inflammasome pathway in the immunity against clinically relevant A. baumannii infections, and highlights inflammasome pathway as a potential immunomodulatory target.
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Affiliation(s)
- N Dikshit
- Program in Emerging Infectious Diseases, Duke-NUS Medical School, Singapore, Singapore
| | - S D Kale
- Program in Emerging Infectious Diseases, Duke-NUS Medical School, Singapore, Singapore
| | - H J Khameneh
- Singapore Immunology Network (SIgN), Agency for Science, Technology and Research (A*STAR), Singapore, Singapore
| | - V Balamuralidhar
- Program in Emerging Infectious Diseases, Duke-NUS Medical School, Singapore, Singapore
| | - C Y Tang
- Life Sciences Institute, National University of Singapore, Singapore, Singapore
| | - P Kumar
- Program in Emerging Infectious Diseases, Duke-NUS Medical School, Singapore, Singapore
| | - T P Lim
- Department of Pharmacy, Singapore General Hospital, Singapore.,Sing Health Duke-NUS Medicine Academic Clinical Programme (MED ACP), Singapore, Singapore
| | - T T Tan
- Department of Infectious Diseases, Singapore General Hospital, Singapore, Singapore
| | - A L Kwa
- Program in Emerging Infectious Diseases, Duke-NUS Medical School, Singapore, Singapore.,Department of Pharmacy, Singapore General Hospital, Singapore.,Sing Health Duke-NUS Medicine Academic Clinical Programme (MED ACP), Singapore, Singapore.,Department of Pharmacy, National University of Singapore, Singapore, Singapore
| | - A Mortellaro
- Singapore Immunology Network (SIgN), Agency for Science, Technology and Research (A*STAR), Singapore, Singapore
| | - B Sukumaran
- Program in Emerging Infectious Diseases, Duke-NUS Medical School, Singapore, Singapore
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