Production of matrix metalloproteinases in response to mycobacterial infection


Quiding-Jarbrink, M; Smith, DA; Bancroft, GJ; (2001) Production of matrix metalloproteinases in response to mycobacterial infection. Infection and immunity, 69 (9). pp. 5661-70. ISSN 0019-9567

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Abstract

Matrix metalloproteinases (MMPs) constitute a large family of enzymes with specificity for the various proteins of the extracellular matrix which are implicated in tissue remodeling processes and chronic inflammatory conditions. To investigate the role of MMPs in immunity to mycobacterial infections, we incubated murine peritoneal macrophages with viable Mycobacterium bovis BCG or Mycobacterium tuberculosis H37Rv and assayed MMP activity in the supernatants by zymography. Resting macrophages secreted only small amounts of MMP-9 (gelatinase B), but secretion increased dramatically in a dose-dependent manner in response to either BCG or M. tuberculosis in vitro. Incubation with mycobacteria also induced increased MMP-2 (gelatinase A) activity. Neutralization of tumor necrosis alpha (TNF-alpha), and to a lesser extent interleukin 18 (IL-18), substantially reduced MMP production in response to mycobacteria. Exogenous addition of TNF-alpha or IL-18 induced macrophages to express MMPs, even in the absence of bacteria. The immunoregulatory cytokines gamma interferon (IFN-gamma), IL-4, and IL-10 all suppressed BCG-induced MMP production, but through different mechanisms. IFN-gamma treatment increased macrophage secretion of TNF-alpha but still reduced their MMP activity. Conversely, IL-4 and IL-10 seemed to act by reducing the amount of TNF-alpha available to the macrophages. Finally, infection of BALB/c or severe combined immunodeficiency (SCID) mice with either BCG or M. tuberculosis induced substantial increases in MMP-9 activity in infected tissues. In conclusion, we show that mycobacterial infection induces MMP-9 activity both in vitro and in vivo and that this is regulated by TNF-alpha, IL-18, and IFN-gamma. These findings indicate a possible contribution of MMPs to tissue remodeling processes that occur in mycobacterial infections.

Item Type: Article
Keywords: Animal, Cells, Cultured, Gelatinase A/*metabolism, Gelatinase B/*metabolism, Macrophage Activation, Macrophages, Peritoneal/*enzymology/microbiology, Mice, Mice, Inbred BALB C, Mice, SCID, Mycobacterium bovis/*immunology, Mycobacterium tuberculosis/*immunology, Support, Non-U.S. Gov't, Tuberculosis/enzymology/*microbiology, Tumor Necrosis Factor/metabolism, Animal, Cells, Cultured, Gelatinase A, metabolism, Gelatinase B, metabolism, Macrophage Activation, Macrophages, Peritoneal, enzymology, microbiology, Mice, Mice, Inbred BALB C, Mice, SCID, Mycobacterium bovis, immunology, Mycobacterium tuberculosis, immunology, Support, Non-U.S. Gov't, Tuberculosis, enzymology, microbiology, Tumor Necrosis Factor, metabolism
Faculty and Department: Faculty of Infectious and Tropical Diseases > Dept of Immunology and Infection
Research Centre: TB Centre
PubMed ID: 11500442
Web of Science ID: 170540000055
URI: http://researchonline.lshtm.ac.uk/id/eprint/16610

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