Dynamic compression counteracts IL-1B inducible nitric synthase and cyclo-oxygenese-2 expression in chondrocyte/agarose constructs
Dynamic compression counteracts IL-1B inducible nitric synthase and cyclo-oxygenese-2 expression in chondrocyte/agarose constructs
Background: Nitric oxide and prostaglandin E2 (PGE2play pivotal roles in both the pathogenesis of osteoarthritis and catabolic processes in articular cartilage. These mediators are influenced by both IL-1? and mechanical loading, and involve alterations in the inducible nitric oxide synthase (iNOS) and cyclo-oxygenase (COX)-2 enzymes. To identify the specific interactions that are activated by both types of stimuli, we examined the effects of dynamic compression on levels of expression of iNOS and COX-2 and involvement of the p38 mitogen-activated protein kinase (MAPK) pathway.
Methods: Chondrocyte/agarose constructs were cultured under free-swelling conditions with or without IL-1? and/or SB203580 (inhibitor of p38 MAPK) for up to 48 hours. Using a fully characterized bioreactor system, constructs were subjected to dynamic compression for 6, 12 and 48 hours under similar treatments. The activation or inhibition of p38 MAPK by IL-1? and/or SB203580 was analyzed by western blotting. iNOS, COX-2, aggrecan and collagen type II signals were assessed utilizing real-time quantitative PCR coupled with molecular beacons. Release of nitrite and PGE2 was quantified using biochemical assays. Two-way analysis of variance and the post hoc Bonferroni-corrected t-test were used to examine data.
Results: IL-1? activated the phosphorylation of p38 MAPK and this effect was abolished by SB203580. IL-1? induced a transient increase in iNOS expression and stimulated the production of nitrite release. Stimulation by either dynamic compression or SB203580 in isolation reduced the IL-1? induced iNOS expression and nitrite production. However, co-stimulation with both dynamic compression and SB203580 inhibited the expression levels of iNOS and production of nitrite induced by the cytokine. IL-1? induced a transient increase in COX-2 expression and stimulated the cumulative production of PGE2 release. These effects were inhibited by dynamic compression or SB203580. Co-stimulation with both dynamic compression and SB203580 restored cytokine-induced inhibition of aggrecan expression. This is in contrast to collagen type II, in which we observed no response with the cytokine and/or SB203580.
Conclusion: These data suggest that dynamic compression directly influences the expression levels of iNOS and COX-2. These molecules are current targets for pharmacological intervention, raising the possibility for integrated pharmacological and biophysical therapies for the treatment of cartilage joint disorders.
R35-[13pp]
Chowdhury, T.T.
3969bc1d-acec-4cad-b523-c8b4885fcb0a
Arghandawi, S.
8f25fb82-48ae-4851-b07f-563fa45eb6aa
Brand, J.
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Akanji, O.O.
49ec1295-ca48-4e46-bc0d-fe9d3efd5e14
Bader, D.L.
9884d4f6-2607-4d48-bf0c-62bdcc0d1dbf
Salter, D.M.
94485705-ebda-4ddf-96c9-55fc6c3fe073
Lee, D.A.
fbbf7169-d08b-4deb-ae87-a2cbd97c58e7
2008
Chowdhury, T.T.
3969bc1d-acec-4cad-b523-c8b4885fcb0a
Arghandawi, S.
8f25fb82-48ae-4851-b07f-563fa45eb6aa
Brand, J.
819943f0-2c7f-495f-bc84-962f278d748e
Akanji, O.O.
49ec1295-ca48-4e46-bc0d-fe9d3efd5e14
Bader, D.L.
9884d4f6-2607-4d48-bf0c-62bdcc0d1dbf
Salter, D.M.
94485705-ebda-4ddf-96c9-55fc6c3fe073
Lee, D.A.
fbbf7169-d08b-4deb-ae87-a2cbd97c58e7
Chowdhury, T.T., Arghandawi, S., Brand, J., Akanji, O.O., Bader, D.L., Salter, D.M. and Lee, D.A.
(2008)
Dynamic compression counteracts IL-1B inducible nitric synthase and cyclo-oxygenese-2 expression in chondrocyte/agarose constructs.
Arthritis Research & Therapy, 10 (2), .
(doi:10.1186/ar2389).
(PMID:18348730)
Abstract
Background: Nitric oxide and prostaglandin E2 (PGE2play pivotal roles in both the pathogenesis of osteoarthritis and catabolic processes in articular cartilage. These mediators are influenced by both IL-1? and mechanical loading, and involve alterations in the inducible nitric oxide synthase (iNOS) and cyclo-oxygenase (COX)-2 enzymes. To identify the specific interactions that are activated by both types of stimuli, we examined the effects of dynamic compression on levels of expression of iNOS and COX-2 and involvement of the p38 mitogen-activated protein kinase (MAPK) pathway.
Methods: Chondrocyte/agarose constructs were cultured under free-swelling conditions with or without IL-1? and/or SB203580 (inhibitor of p38 MAPK) for up to 48 hours. Using a fully characterized bioreactor system, constructs were subjected to dynamic compression for 6, 12 and 48 hours under similar treatments. The activation or inhibition of p38 MAPK by IL-1? and/or SB203580 was analyzed by western blotting. iNOS, COX-2, aggrecan and collagen type II signals were assessed utilizing real-time quantitative PCR coupled with molecular beacons. Release of nitrite and PGE2 was quantified using biochemical assays. Two-way analysis of variance and the post hoc Bonferroni-corrected t-test were used to examine data.
Results: IL-1? activated the phosphorylation of p38 MAPK and this effect was abolished by SB203580. IL-1? induced a transient increase in iNOS expression and stimulated the production of nitrite release. Stimulation by either dynamic compression or SB203580 in isolation reduced the IL-1? induced iNOS expression and nitrite production. However, co-stimulation with both dynamic compression and SB203580 inhibited the expression levels of iNOS and production of nitrite induced by the cytokine. IL-1? induced a transient increase in COX-2 expression and stimulated the cumulative production of PGE2 release. These effects were inhibited by dynamic compression or SB203580. Co-stimulation with both dynamic compression and SB203580 restored cytokine-induced inhibition of aggrecan expression. This is in contrast to collagen type II, in which we observed no response with the cytokine and/or SB203580.
Conclusion: These data suggest that dynamic compression directly influences the expression levels of iNOS and COX-2. These molecules are current targets for pharmacological intervention, raising the possibility for integrated pharmacological and biophysical therapies for the treatment of cartilage joint disorders.
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e-pub ahead of print date: 18 March 2008
Published date: 2008
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Health Sciences
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Local EPrints ID: 169057
URI: http://eprints.soton.ac.uk/id/eprint/169057
ISSN: 1478-6354
PURE UUID: f9c4cdca-9108-4059-8e5d-2503921eacb6
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Date deposited: 09 Dec 2010 09:45
Last modified: 14 Mar 2024 02:19
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Author:
T.T. Chowdhury
Author:
S. Arghandawi
Author:
J. Brand
Author:
O.O. Akanji
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D.M. Salter
Author:
D.A. Lee
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