Differential expression of GADD45β in normal and osteoarthritic cartilage: Potential role in homeostasis of articular chondrocytes

Authors

  • Kosei Ijiri,

    1. Beth Israel Deaconess Medical Center, and New England Baptist Bone and Joint Institute, Boston, Massachusetts
    Current affiliation:
    1. Kagoshima University, Kagoshima, Japan
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  • Luiz F. Zerbini,

    1. Beth Israel Deaconess Medical Center, and New England Baptist Bone and Joint Institute, Boston, Massachusetts
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  • Haibing Peng,

    1. Beth Israel Deaconess Medical Center, and New England Baptist Bone and Joint Institute, Boston, Massachusetts
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  • Hasan H. Otu,

    1. Beth Israel Deaconess Medical Center, and New England Baptist Bone and Joint Institute, Boston, Massachusetts
    Current affiliation:
    1. Yeditepe University, Istanbul, Turkey
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  • Kaneyuki Tsuchimochi,

    1. Beth Israel Deaconess Medical Center, and New England Baptist Bone and Joint Institute, Boston, Massachusetts
    Current affiliation:
    1. Hospital for Special Surgery, and Weill College of Medicine of Cornell University, New York, New York
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  • Miguel Otero,

    1. Beth Israel Deaconess Medical Center, and New England Baptist Bone and Joint Institute, Boston, Massachusetts
    Current affiliation:
    1. Hospital for Special Surgery, and Weill College of Medicine of Cornell University, New York, New York
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  • Cecilia Dragomir,

    1. Hospital for Special Surgery, and Weill College of Medicine of Cornell University, New York, New York
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  • Nicole Walsh,

    1. Beth Israel Deaconess Medical Center, and New England Baptist Bone and Joint Institute, Boston, Massachusetts
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  • Benjamin E. Bierbaum,

    1. New England Baptist Hospital, Boston, Massachusetts
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  • David Mattingly,

    1. New England Baptist Hospital, Boston, Massachusetts
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    • Dr. Mattingly has received consulting fees, speaking fees, and/or honoraria (more than $10,000) from DePuy, a Johnson & Johnson company, and he receives royalties from DePuy for the S-ROM hip replacement system.

  • Geoff van Flandern,

    1. New England Baptist Hospital, Boston, Massachusetts
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  • Setsuro Komiya,

    1. Kagoshima University, Kagoshima, Japan
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  • Thomas Aigner,

    1. Institute of Pathology, and University of Leipzig, Leipzig, Germany
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  • Towia A. Libermann,

    1. Beth Israel Deaconess Medical Center, and New England Baptist Bone and Joint Institute, Boston, Massachusetts
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  • Mary B. Goldring

    Corresponding author
    1. Beth Israel Deaconess Medical Center, and New England Baptist Bone and Joint Institute, Boston, Massachusetts
    Current affiliation:
    1. Hospital for Special Surgery, and Weill College of Medicine of Cornell University, New York, New York
    • Laboratory for Cartilage Biology, Hospital for Special Surgery, Caspary Research Building, Room 528, 535 East 70th Street, New York, NY 10021
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Abstract

Objective

Our previous study suggested that growth arrest and DNA damage–inducible protein 45β (GADD45β) prolonged the survival of hypertrophic chondrocytes in the developing mouse embryo. This study was undertaken, therefore, to investigate whether GADD45β plays a role in adult articular cartilage.

Methods

Gene expression profiles of cartilage from patients with late-stage osteoarthritis (OA) were compared with those from patients with early OA and normal controls in 2 separate microarray analyses. Histologic features of cartilage were graded using the Mankin scale, and GADD45β was localized by immunohistochemistry. Human chondrocytes were transduced with small interfering RNA (siRNA)–GADD45β or GADD45β-FLAG. GADD45β and COL2A1 messenger RNA (mRNA) levels were analyzed by real-time reverse transcriptase–polymerase chain reaction, and promoter activities were analyzed by transient transfection. Cell death was detected by Hoechst 33342 staining of condensed chromatin.

Results

GADD45β was expressed at higher levels in cartilage from normal donors and patients with early OA than in cartilage from patients with late-stage OA. All chondrocyte nuclei in normal cartilage immunostained for GADD45β. In early OA cartilage, GADD45β was distributed variably in chondrocyte clusters, in middle and deep zone cells, and in osteophytes. In contrast, COL2A1, other collagen genes, and factors associated with skeletal development were up-regulated in late OA, compared with early OA or normal cartilage. In overexpression and knockdown experiments, GADD45β down-regulated COL2A1 mRNA and promoter activity. NF-κB overexpression increased GADD45β promoter activity, and siRNA-GADD45β decreased cell survival per se and enhanced tumor necrosis factor α–induced cell death in human articular chondrocytes.

Conclusion

These observations suggest that GADD45β might play an important role in regulating chondrocyte homeostasis by modulating collagen gene expression and promoting cell survival in normal adult cartilage and in early OA.

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