Protein kinase a mediated anti-inflammatory effects exerted by adenosine treatment in mouse chondrocytes stimulated with IL-1β

Authors

  • Giuseppe M. Campo,

    Corresponding author
    1. Department of Biochemical, Physiological and Nutritional Sciences, Section of Medical Chemistry, School of Medicine, University of Messina, Policlinico Universitario, 98125 Messina, Italy
    • Department of Biochemical, Physiological and Nutritional Sciences, School of Medicine, University of Messina, Policlinico Universitario, Torre Biologica, 5° piano, Via C. Valeria 98125, Messina, Italy
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    • Tel.: +39 090 221 3334; Fax: +39 090 221 3898

  • Angela Avenoso,

    1. Department of Biochemical, Physiological and Nutritional Sciences, Section of Medical Chemistry, School of Medicine, University of Messina, Policlinico Universitario, 98125 Messina, Italy
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  • Angela D'Ascola,

    1. Department of Biochemical, Physiological and Nutritional Sciences, Section of Medical Chemistry, School of Medicine, University of Messina, Policlinico Universitario, 98125 Messina, Italy
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  • Vera Prestipino,

    1. Department of Biochemical, Physiological and Nutritional Sciences, Section of Medical Chemistry, School of Medicine, University of Messina, Policlinico Universitario, 98125 Messina, Italy
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  • Michele Scuruchi,

    1. Department of Biochemical, Physiological and Nutritional Sciences, Section of Medical Chemistry, School of Medicine, University of Messina, Policlinico Universitario, 98125 Messina, Italy
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  • Giancarlo Nastasi,

    1. Department of Biochemical, Physiological and Nutritional Sciences, Section of Medical Chemistry, School of Medicine, University of Messina, Policlinico Universitario, 98125 Messina, Italy
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  • Alberto Calatroni,

    1. Department of Biochemical, Physiological and Nutritional Sciences, Section of Medical Chemistry, School of Medicine, University of Messina, Policlinico Universitario, 98125 Messina, Italy
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  • Salvatore Campo

    1. Department of Biochemical, Physiological and Nutritional Sciences, Section of Medical Chemistry, School of Medicine, University of Messina, Policlinico Universitario, 98125 Messina, Italy
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Abstract

Hyaluronan (HA) fragments produced by degradation of native highly polymerized HA during inflammation may exacerbate proinflammatory responses in different pathologies. In contrast, the nucleoside adenosine (ADO) interacting with cell surface adenosine receptors A2AR, A2BR, A1, and A3, acts as endogenous modulator of the inflammation. The engagement of high-affinity A2AR by ADO activates a pathway leading to increased cAMP production. Elevated levels of cAMP associate with the activation of protein kinase A (PKA) able to inhibit NF-kB, hence exerting anti-inflammatory activity. In this study the effect of ADO treatment in normal murine chondrocytes stimulated with interleukin-1beta (IL-1beta) was investigated. mRNA and related protein levels were measured for enzymes, receptors and pro-inflammatory cytokines TNF-alpha, IL-6 and Il-18. IL-1beta stimulation significantly up-regulated HA levels, its fragmentation, cAMP, PKA, cytokine levels, and activated NF-kB. ADO treatment increased cAMP and PKA levels, while reduced NF-kB activation and cytokine levels. HA inhibition by specific synthetic HA blocking peptide (Pep-1) reduced IL-1beta action but not ADO activity. While A2AR inhibition by specific small interference RNA (siRNA) increased inflammation and decreased cAMP and PKA levels. This study suggests that HA is partially responsible for the up-regulation of proinflammatory cytokines in chondrocytes and that endogenous/exogenous ADO may reduce inflammation via PKA. © 2012 International Union of Biochemistry and Molecular Biology, Inc.

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