Monocyte-dependent fibroblast CXCL8 secretion occurs in tuberculosis and limits survival of mycobacteria within macrophages
Monocyte-dependent fibroblast CXCL8 secretion occurs in tuberculosis and limits survival of mycobacteria within macrophages
CXCL8 is a chemokine that is implicated in the formation of tuberculous (TB) granulomas and in immunity to Mycobacterium tuberculosis (Mtb). Fibroblast chemokine secretion is important for modulating inflammatory responses in chronic lung disease and inflammatory arthritis but has not been investigated in the pathophysiology of TB. In this study, we used a cellular model to examine monocyte/macrophage-dependent stimulation of fibroblasts by Mtb in the regulation of chemokine secretion, particularly that of CXCL8. Human lung fibroblasts grown in collagen were stimulated with conditioned medium from Mtb-infected monocytes (CoMTb). CoMTb-induced prolonged dose-dependent, p38-mediated expression of stable CXCL8 mRNA by fibroblasts accompanied by a >10-fold increase in CXCL8 secretion (487 +/- 88 ng/ml vs 48.6 +/- 34 ng/ml in controls) at 120 h. Fibroblasts strongly expressed CXCL8 in vivo in human TB granulomas. Inhibition of TNF-alpha or IL-1 in CoMTb abrogated the induction of CXCL8 at a pretranscriptional level. CXCL8 secretion was NF-kappaB, C/EBP, and JNK dependent. Sustained NF-kappaB activation was demonstrated beyond 24 h in response to CoMTb. Exogenous CXCL8 reduced the survival of Mtb within macrophages, and inhibition of CXCL8 was associated with intracellular mycobacterial proliferation. These data show that fibroblasts have a previously unrecognized role in modulating inflammation in TB by their CXCL8-dependent contribution to cell recruitment and mycobacterial killing within the granuloma.
3767-3776
O'Kane, Cecilia M.
67033ab5-9527-4a98-bf08-3c5560e91098
Boyle, Joseph J.
df42af17-4f90-4ff6-9f87-b85c1c15e124
Horncastle, Donna E.
c9ffce42-5c26-4ec2-9368-24b93f5259cb
Elkington, Paul T.
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Friedland, Jon S.
9968669f-afe0-4163-9b35-3b476246fd4a
15 March 2007
O'Kane, Cecilia M.
67033ab5-9527-4a98-bf08-3c5560e91098
Boyle, Joseph J.
df42af17-4f90-4ff6-9f87-b85c1c15e124
Horncastle, Donna E.
c9ffce42-5c26-4ec2-9368-24b93f5259cb
Elkington, Paul T.
60828c7c-3d32-47c9-9fcc-6c4c54c35a15
Friedland, Jon S.
9968669f-afe0-4163-9b35-3b476246fd4a
O'Kane, Cecilia M., Boyle, Joseph J., Horncastle, Donna E., Elkington, Paul T. and Friedland, Jon S.
(2007)
Monocyte-dependent fibroblast CXCL8 secretion occurs in tuberculosis and limits survival of mycobacteria within macrophages.
Journal of Immunology, 178 (6), .
(PMID:17339475)
Abstract
CXCL8 is a chemokine that is implicated in the formation of tuberculous (TB) granulomas and in immunity to Mycobacterium tuberculosis (Mtb). Fibroblast chemokine secretion is important for modulating inflammatory responses in chronic lung disease and inflammatory arthritis but has not been investigated in the pathophysiology of TB. In this study, we used a cellular model to examine monocyte/macrophage-dependent stimulation of fibroblasts by Mtb in the regulation of chemokine secretion, particularly that of CXCL8. Human lung fibroblasts grown in collagen were stimulated with conditioned medium from Mtb-infected monocytes (CoMTb). CoMTb-induced prolonged dose-dependent, p38-mediated expression of stable CXCL8 mRNA by fibroblasts accompanied by a >10-fold increase in CXCL8 secretion (487 +/- 88 ng/ml vs 48.6 +/- 34 ng/ml in controls) at 120 h. Fibroblasts strongly expressed CXCL8 in vivo in human TB granulomas. Inhibition of TNF-alpha or IL-1 in CoMTb abrogated the induction of CXCL8 at a pretranscriptional level. CXCL8 secretion was NF-kappaB, C/EBP, and JNK dependent. Sustained NF-kappaB activation was demonstrated beyond 24 h in response to CoMTb. Exogenous CXCL8 reduced the survival of Mtb within macrophages, and inhibition of CXCL8 was associated with intracellular mycobacterial proliferation. These data show that fibroblasts have a previously unrecognized role in modulating inflammation in TB by their CXCL8-dependent contribution to cell recruitment and mycobacterial killing within the granuloma.
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Published date: 15 March 2007
Organisations:
Faculty of Medicine
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Local EPrints ID: 341063
URI: http://eprints.soton.ac.uk/id/eprint/341063
ISSN: 0022-1767
PURE UUID: a045747b-5a7d-4e02-a356-aabb334998ee
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Date deposited: 12 Jul 2012 10:38
Last modified: 23 Jul 2022 02:05
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Author:
Cecilia M. O'Kane
Author:
Joseph J. Boyle
Author:
Donna E. Horncastle
Author:
Jon S. Friedland
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