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InhA1-Mediated Cleavage of the Metalloprotease NprA Allows Bacillus cereus to Escape From Macrophages

Authors :
Abbass Haydar
Seav-Ly Tran
Elisabeth Guillemet
Claire Darrigo
Stéphane Perchat
Didier Lereclus
Laurent Coquet
Thierry Jouenne
Nalini Ramarao
Source :
Frontiers in Microbiology, Vol 9 (2018)
Publication Year :
2018
Publisher :
Frontiers Media S.A., 2018.

Abstract

Bacillus cereus is a Gram-positive spore-forming bacterium causing food poisoning and serious opportunistic infections. These infections are characterized by bacterial accumulation in the host despite the induction of inflammation. To circumvent inflammation, bacteria must resist the bactericidal activity of professional phagocytes, which constitute a first line of host defense against pathogens. Interactions between phagocytic cells and B. cereus are still poorly characterized and the mechanism of resistance to the host immune system is not known yet. We have previously shown that the spores are phagocytosed by macrophages but survive and escape from these cells. The metalloprotease InhA1 is a key effector involved in these processes. inhA1-deficient spores are retained intracellularly, in contrast to the wild type strain spores. NprA is also a B. cereus metalloprotease able to cleave tissue components such as fibronectin, laminin, and collagen. Here, we show that NprA, concomitantly secreted with InhA1 in the B. cereus secretome, is essential to promote bacterial escape from macrophages. We show that InhA1 cleaves NprA at specific sites. This cleavage allows liberation of the mature form of the NprA protein in the supernatant of the wild type strain. This mature form of NprA is actually the principal effector allowing bacterial escape from host macrophages.

Details

Language :
English
ISSN :
1664302X
Volume :
9
Database :
Directory of Open Access Journals
Journal :
Frontiers in Microbiology
Publication Type :
Academic Journal
Accession number :
edsdoj.0d8386d2bca0490a8f05d6050bf261d1
Document Type :
article
Full Text :
https://doi.org/10.3389/fmicb.2018.01063