Arthritis & Rheumatism, Volume 62,
November 2010 Abstract Supplement

Abstracts of the American College of
Rheumatology/Association of Rheumatology Health Professionals
Annual Scientific Meeting
Atlanta, Georgia November 6-11, 2010.


Expression of MMP-13 and ADAMTS-5 Is Mediated Via Nuclear Orphan Receptor NR4A3 Signalling in Human Chondrocytes.

Stradner2,  Martin H., Angerer3,  Hannes, Krusch1,  Daniela, Furst3,  Florentine C., Kremser3,  Marie-Luise, Setznagl3,  Daniela, Graninger3,  Winfried B.

Karl-Franzens University Graz
Medical University Graz, Graz, Austria
Medical University Graz

Purpose:

Nuclear orphan receptors act as ligand-independent transcriptionally activated regulator proteins. In a global analysis of nuclear receptor expression in OA cartilage by Collins-Racie et.al. the nuclear orphan receptor NR4A3 was found to be highly deregulated. As its function in chondrocytes is still unknown, we evaluated the influence of NR4A3 on chondrocyte gene expression.

Methods:

Human cartilage specimens were obtained from patients undergoing total knee joint replacement. Chondrocytes were isolated using collagenase B. Primary human chondrocytes and the human chondrocyte cell-line C28I2 were grown in monolayer and cultured in Ham's F-12/DMEM (1:1) and 10% FCS. Expression of NR4A3 was evaluated by reverse-transcriptase PCR. For siRNA knock-down of NR4A3 C28I2 cells were transfected with specific anti-sense oligonucleotides using lipofectamine. After 24h gene expression of ADAMTS-4 and -5, MMP-13, iNOS, aggrecan and pro-collagen II, was investigated using real-time PCR.

Results:

NR4A3 mRNA was found to be expressed in OA chondrocytes and the C28I2 cell-line. siRNA knock-down achieved 60% (± 4%) reduction of NR4A3 mRNA expression. The decrease in NR4A3 expression led to a decline of MMP-13 expression by 52% (± 9%). Furthermore ADAMTS-5 mRNA expression was reduced by 50% (± 3%). Gene expression of ADAMTS-4, iNOS, aggrecan and pro-collagen II remained unaltered in the presence of diminished NR4A3 expression.

Conclusions:

We confirmed the expression of the nuclear orphan receptor NR4A3 in OA chondrocytes and C28I2 cells. Furthermore its presence is required for maintenance of MMP-13 and ADAMTS-5 expression. Therefore NR4A3 could be a novel promising therapeutic target in OA chondrocytes.

To cite this abstract, please use the following information:
Stradner, Martin H., Angerer, Hannes, Krusch, Daniela, Furst, Florentine C., Kremser, Marie-Luise, Setznagl, Daniela, et al; Expression of MMP-13 and ADAMTS-5 Is Mediated Via Nuclear Orphan Receptor NR4A3 Signalling in Human Chondrocytes. [abstract]. Arthritis Rheum 2010;62 Suppl 10 :1481
DOI: 10.1002/art.29247

Abstract Supplement

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