Abstract
Leptospirosis is a worldwide zoonosis caused by spirochetes from the genus Leptospira. Although there is a large diversity of clinical signs and symptoms, a severe inflammatory response is common to all leptospirosis patients. The mechanism of IL-1β secretion during Leptospira infection has been previously studied in mouse macrophages. However, the outcome of Leptospira infection is very different in human and murine macrophages, and the mechanisms responsible for IL-1β secretion in human macrophages had not been investigated. This study therefore examines the effects of Leptospira interrogans infection on inflammasome activation and proinflammatory cytokine expression in human macrophages. Increased mRNA and protein expression of NLRP3 was observed by real time RT-PCR and flow cytometry at 1 h after co-cultivation. Enzyme-linked immunosorbent assay (ELISA) determination showed that IL-1β and IL-18 are released in the culture supernatants at 1 h after cultivation. The inhibition assay showed that glybenclamide (a K+ efflux inhibitor that blocks NLRP3 inflammasome activation) and N-benzyloxycarbony-Val-Ala-Asp (O-methyl)-fluoromethylketone (Z-VAD-FMK; a caspase-1 inhibitor) and NLRP3 depletion with siRNAs reduced the levels of IL-1β and IL-18 release. Moreover, the levels of IL-1β and IL-18 production decreased in CA-074 (a cathepsin B inhibitor) and NAC (an anti-oxidant) pretreated human macrophages, compared to untreated controls. This study suggests that L. interrogans infection leads to reactive oxygen species (ROS)- and cathepsin B-dependent NLRP3 inflammasome activation, which subsequently mediates caspase-1 activation and IL-1β and IL-18 release.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.