Volume 50, Issue 1 pp. 247-258
Research Article

Proline-rich tyrosine kinase 2 and Src kinase signaling transduce monosodium urate crystal–induced nitric oxide production and matrix metalloproteinase 3 expression in chondrocytes

Ru Liu

Ru Liu

VA Medical Center and University of California, San Diego

Drs. Liu and Lioté contributed equally to this work.

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Frédéric Lioté

Frédéric Lioté

Hôpital Lariboisière, Paris 7 University, Paris, France

Drs. Liu and Lioté contributed equally to this work.

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David M. Rose

David M. Rose

VA Medical Center and University of California, San Diego

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Denise Merz

Denise Merz

VA Medical Center and University of California, San Diego

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Robert Terkeltaub

Corresponding Author

Robert Terkeltaub

VA Medical Center and University of California, San Diego

VA Medical Center, MC111K, 3350 La Jolla Village Drive, San Diego, CA 92161Search for more papers by this author
First published: 09 January 2004
Citations: 72

Abstract

Objective

Articular deposition of monosodium urate monohydrate (MSU) crystals may promote cartilage and bone erosion. Therefore, the aim of this study was to determine how MSU crystals stimulate chondrocytes.

Methods

Nitric oxide (NO) release, and expression of inducible nitric oxide synthase (iNOS) and matrix metalloproteinase 3 (MMP-3) were assessed in cultured chondrocytes treated with MSU. MSU-induced functional signaling by specific protein kinases (p38, Src, and the focal adhesion kinase [FAK] family members proline-rich tyrosine kinase 2 [Pyk-2] and FAK) was also examined using selective pharmacologic inhibitors and transfection of kinase mutants.

Results

MSU induced MMP-3 and iNOS expression and NO release in chondrocytes in a p38-dependent manner that did not require interleukin-1 (IL-1), as demonstrated by using IL-1 receptor antagonist. MSU induced rapid tyrosine phosphorylation of Pyk-2 and FAK, their adaptor protein paxillin, and interacting kinase c-Src. Pyk-2 and c-Src signaling both mediated p38 MAPK activation in response to MSU. Pyk-2 and c-Src signaling played a major role in transducing MSU-induced NO production and MMP-3 expression. But, despite the observed FAK phosphorylation, a selective pharmacologic FAK inhibitor and a FAK dominant-negative mutant both failed to block MSU-induced NO release or MMP-3 expression in parallel experiments.

Conclusion

In chondrocytes, MSU crystals activate a signaling kinase cascade typically employed by adhesion receptors that involves upstream Src and FAK family activation and downstream p38 activation. In this cascade, Pyk-2, Src, and p38 kinases transduce MSU-induced NO production and MMP-3 expression. Our results identify Pyk-2 and c-Src as novel sites for potential therapeutic intervention in cartilage degradation in chronic gout.

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