In:
The Journal of Immunology, The American Association of Immunologists, Vol. 184, No. 11 ( 2010-06-01), p. 6492-6503
Abstract:
Inflammatory tissue destruction is central to pathology in CNS tuberculosis (TB). We hypothesized that microglial-derived matrix metalloproteinases (MMPs) have a key role in driving such damage. Analysis of all of the MMPs demonstrated that conditioned medium from Mycobacterium tuberculosis-infected human monocytes (CoMTb) stimulated greater MMP-1, -3, and -9 gene expression in human microglial cells than direct infection. In patients with CNS TB, MMP-1/-3 immunoreactivity was demonstrated in the center of brain granulomas. Concurrently, CoMTb decreased expression of the inhibitors, tissue inhibitor of metalloproteinase-2, -3, and -4. MMP-1/-3 secretion was significantly inhibited by dexamethasone, which reduces mortality in CNS TB. Surface-enhanced laser desorption ionization time-of-flight analysis of CoMTb showed that TNF-α and IL-1β are necessary but not sufficient for upregulating MMP-1 secretion and act synergistically to drive MMP-3 secretion. Chemical inhibition and promoter-reporter analyses showed that NF-κB and AP-1 c-Jun/FosB heterodimers regulate CoMTb-induced MMP-1/-3 secretion. Furthermore, NF-κB p65 and AP-1 c-Jun subunits were upregulated in biopsy granulomas from patients with cerebral TB. In summary, functionally unopposed, network-dependent microglial MMP-1/-3 gene expression and secretion regulated by NF-κB and AP-1 subunits were demonstrated in vitro and, for the first time, in CNS TB patients. Dexamethasone suppression of MMP-1/-3 gene expression provides a novel mechanism explaining the benefit of steroid therapy in these patients.
Type of Medium:
Online Resource
ISSN:
0022-1767
,
1550-6606
DOI:
10.4049/jimmunol.0903811
Language:
English
Publisher:
The American Association of Immunologists
Publication Date:
2010
detail.hit.zdb_id:
1475085-5
detail.hit.zdb_id:
3056-9
