Abstract
Pathogenic mycobacteria actively dysregulate protective host immune signalling pathways during infection to drive the formation of permissive granuloma microenvironments. Dynamic regulation of host microRNA (miRNA) expression is a conserved feature of mycobacterial infections across host-pathogen pairings. Here we examine the role of miR-206 in the zebrafish model of Mycobacterium marinum infection, which allows investigation of the early stages of granuloma formation. We find miR-206 is upregulated following infection by pathogenic M. marinum and that antagomir-mediated knockdown of miR-206 is protective against infection. We observed striking upregulation of cxcl12a and cxcr4b in infected miR-206 knockdown zebrafish embryos and live imaging revealed enhanced recruitment of neutrophils to sites of infection. We used CRISPR/Cas9-mediated knockdown of cxcl12a and cxcr4b expression and AMD3100 inhibition of Cxcr4 to show that the enhanced neutrophil response and reduced bacterial burden caused by miR-206 knockdown was dependent on the Cxcl12/Cxcr4 signalling axis. Together, our data illustrate a pathway through which pathogenic mycobacteria induce host miR-206 expression to suppress Cxcl12/Cxcr4 signalling and prevent protective neutrophil recruitment to granulomas.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Animals
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Chemokine CXCL12 / immunology
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Chemokine CXCL12 / metabolism*
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Gene Knockdown Techniques / methods
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MicroRNAs / genetics*
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Mycobacterium Infections, Nontuberculous / genetics
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Mycobacterium Infections, Nontuberculous / immunology
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Mycobacterium marinum / metabolism
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Neutrophil Infiltration / immunology*
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Receptors, CXCR4 / immunology
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Receptors, CXCR4 / metabolism*
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Signal Transduction / genetics
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Signal Transduction / immunology
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Zebrafish / immunology
Substances
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CXCL12 protein, human
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CXCR4 protein, human
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Chemokine CXCL12
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MicroRNAs
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Receptors, CXCR4
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mirn206 microRNA, zebrafish
Supplementary concepts
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Infection with Mycobacterium marinum
Grants and funding
Funding for this study was provided to SHO: Australian National Health and Medical Research Council Grant [APP1099912]
https://www.nhmrc.gov.au/, The University of Sydney Fellowship [G197581]
https://www.sydney.edu.au/, NSW Ministry of Health under the NSW Health Early-Mid Career Fellowships Scheme [H18/31086]
https://www.health.nsw.gov.au/; to KdS, KMP, ACP: Meat and Livestock Australia Grant [P.PSH.0813]
https://www.mla.com.au/; to KW Meat and Livestock Australia Grant Higher Degree Research scholarship to KW [P.PSH.0813 HDR scholarship]
https://www.mla.com.au/; to WJB: Australian National Health and Medical Research Council Centres of Research Excellence Grant [APP1153493]
https://www.nhmrc.gov.au/. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.