PKC-ζ expression is lower in osteoblasts from arthritic patients: IL1-β and TNF-α induce a similar decrease in non-arthritic human osteoblasts

Authors

  • Nicoletta Zini,

    Corresponding author
    1. IGM-CNR, Sezione di Bologna c/o IOR, via di Barbiano 1/10, 40136 Bologna, Italy
    • IGM-CNR, Sezione di Bologna c/o IOR, Via di Barbiano 1/10, 40136 Bologna, Italy.
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  • Alberto Bavelloni,

    1. Laboratorio di Biologia Cellulare e Microscopia Elettronica, IOR, via di Barbiano 1/10, 40136 Bologna, Italy
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  • Gina Lisignoli,

    1. Laboratorio di Immunologia e Genetica, IOR, via di Barbiano 1/10, 40136 Bologna, Italy
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  • Sonia Ghisu,

    1. Laboratorio di Biologia Cellulare e Microscopia Elettronica, IOR, via di Barbiano 1/10, 40136 Bologna, Italy
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  • Aurelio Valmori,

    1. IGM-CNR, Sezione di Bologna c/o IOR, via di Barbiano 1/10, 40136 Bologna, Italy
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  • Alberto Maria Martelli,

    1. IGM-CNR, Sezione di Bologna c/o IOR, via di Barbiano 1/10, 40136 Bologna, Italy
    2. Dipartimento di Scienze Anatomiche Umane e Fisiopatologia dell'Apparato Locomotore, Sezione di Anatomia, Cell Signalling Laboratory, Università degli Studi di Bologna, via Irnerio 48, 40126 Bologna, Italy
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  • Andrea Facchini,

    1. Laboratorio di Immunologia e Genetica, IOR, via di Barbiano 1/10, 40136 Bologna, Italy
    2. Dipartimento di Medicina Interna e Gastroenterologia, Università degli Studi di Bologna, via Massarenti 9, 40138 Bologna, Italy
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  • Nadir Mario Maraldi

    1. IGM-CNR, Sezione di Bologna c/o IOR, via di Barbiano 1/10, 40136 Bologna, Italy
    2. Laboratorio di Biologia Cellulare e Microscopia Elettronica, IOR, via di Barbiano 1/10, 40136 Bologna, Italy
    3. Dipartimento di Scienze Anatomiche Umane e Fisiopatologia dell'Apparato Locomotore, Sezione di Anatomia, Cell Signalling Laboratory, Università degli Studi di Bologna, via Irnerio 48, 40126 Bologna, Italy
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Abstract

Protein kinase C (PKC) is a family of enzymes detected in a diverse range of cell types where they regulate various cellular functions such as proliferation, differentiation, cytoskeletal remodelling, cytokine production, and receptor-mediated signal transduction. In this study we have analyzed the expression of 11 PKC isoforms (-α, -βI, -βII, -γ, -δ, -η, -θ, -ε, -ζ, -ι/λ, and -µ) in osteoblasts from patients with osteoarthritis (OA) and rheumatoid arthritis (RA) in comparison with osteoblasts from post-traumatic (PT) patients. By Western blotting analysis, nine isoforms, -α, -βI, -βII, -δ, -θ, - ε, -ζ, - ι/λ, and -µ, were detected in osteoblasts. In RA and OA patients, PKC -θ and -µ were greater expressed whereas PKC-ε and -ζ decreased when compared with normal cells. The subcellular distribution and quantitative differences were confirmed by immuno-electron microscopy. Furthermore, we demonstrated that treatment with the proinflammatory cytokines, IL-1β and TNF-α, significantly decreased PKC-ζ expression in PT osteoblasts. This suggests that proinflammatory cytokines can modulate the expression of this PKC isoform in osteoblasts in a way which is similar to changes detected in arthritic patients. J. Cell. Biochem. 103: 547–555, 2008. © 2007 Wiley-Liss, Inc.

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