In:
The Journal of Immunology, The American Association of Immunologists, Vol. 171, No. 10 ( 2003-11-15), p. 5579-5586
Abstract:
Tuberculosis is characterized by granuloma formation and caseous necrosis, but the factors causing tissue destruction are poorly understood. Matrix metalloproteinase (MMP)-9 (92-kDa gelatinase) secretion from monocytes is stimulated by Mycobacterium tuberculosis (M. tb) and associated with local tissue injury in tuberculosis patients. We demonstrate strong immunohistochemical MMP-9 staining in monocytic cells at the center of granuloma and adjacent to caseous necrosis in M. tb-infected patient lymph nodes. Minimal tissue inhibitor of MMPs-1 staining indicated that MMP-9 activity is unopposed. Because granulomas characteristically contain few mycobacteria, we investigated whether monocyte-monocyte cytokine networks amplify MMP-9 secretion. Conditioned medium from M. tb-infected primary human monocytes or THP-1 cells (CoMTB) stimulated MMP-9 gene expression and a & gt;10-fold increase in MMP-9 secretion by monocytes at 3–4 days (p & lt; 0.009, vs controls). Although CoMTB stimulated dose-dependent MMP-9 secretion, MMP-1 (52-kDa collagenase) was not induced. Anti-TNF-α Ab but not IL-1R antagonist pretreatment decreased CoMTB-induced MMP-9 secretion by 50% (p = 0.0001). Anti-TNF-α Ab also inhibited MMP-9 secretion from monocytic cells by 50%, 24 h after direct M. tb infection (p = 0.0002). Conversely, TNF-α directly stimulated dose-dependent MMP-9 secretion. Pertussis toxin inhibited CoMTB-induced MMP-9 secretion and enhanced the inhibitory effect of anti-TNF-α Ab (p = 0.05). Although chemokines bind to G protein-linked receptors, CXCL8, CXCL10, CCL2, and CCL5 did not stimulate monocyte MMP-9 secretion. However, the response to cholera toxin confirmed that G protein signaling pathways were intact. In summary, MMP-9 within tuberculous granuloma is associated with tissue destruction, and TNF-α, critical for antimycobacterial granuloma formation, is a key autocrine and paracrine regulator of MMP-9 secretion.
Type of Medium:
Online Resource
ISSN:
0022-1767
,
1550-6606
DOI:
10.4049/jimmunol.171.10.5579
Language:
English
Publisher:
The American Association of Immunologists
Publication Date:
2003
detail.hit.zdb_id:
1475085-5
detail.hit.zdb_id:
3056-9
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