Beta-arrestin-2 negatively modulates inflammation response in mouse chondrocytes induced by 4-mer hyaluronan oligosaccharide

Mol Cell Biochem. 2015 Jan;399(1-2):201-8. doi: 10.1007/s11010-014-2246-5. Epub 2014 Oct 16.

Abstract

Beta-arrestin-2 is an adaptor protein that terminates G protein activation and seems to be involved in the modulation of the inflammatory response. Small hyaluronan (HA) fragments, such as 4-mer HA oligosaccharides, are known to interact with the toll-like receptor-4 (TLR-4) with consequent activation of the nuclear factor kappaB (NF-kB) that in turn stimulates the inflammation response. NF-kB activation is mediated by different pathways, in particular by the transforming growth factor-activated kinase-1 (TAK-1). Conversely, increased levels of protein kinase A (PKA), induced by cyclic adenosine monophosphate (cAMP), seem to inhibit NF-kB activation. We studied the involvement and role of beta-arrestin-2 in mouse chondrocytes stimulated with 4-mer HA fragments. The exposure of chondrocytes to 4-mer HA produced a significant up-regulation in TLR-4, cAMP, beta-arrestin-2, TAK-1, protein 38 mitogen-activated protein kinase (p38MAPK), and PKA, both in terms of mRNA expression and of the related protein levels. NF-kB was significantly activated, thereby producing the transcription of pro-inflammatory mediators, including tumor necrosis factor alpha, interleukin-6, and interleukin-17. The treatment of 4-mer HA-stimulated chondrocytes with antibodies against beta-arrestin-2 and/or a specific PKA inhibitor, significantly increased the inflammatory response, while the treatment with a specific p38MAPK inhibitor significantly reduced the inflammatory response. Interestingly, the anti-inflammatory action exerted by beta-arrestin-2 appeared to be mediated in part through the direct inhibition of p38MAPK, preventing NF-kB activation, and in part through cAMP and PKA activation primed by G protein signaling, which exerted an inhibitory effect on NF-kB. Taken together, these results could be useful for future anti-inflammatory strategies.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Arrestins / physiology*
  • Cells, Cultured
  • Chondrocytes / immunology
  • Chondrocytes / metabolism*
  • Cyclic AMP-Dependent Protein Kinases / genetics
  • Cyclic AMP-Dependent Protein Kinases / metabolism
  • Gene Expression
  • Hyaluronic Acid / pharmacology*
  • Inflammation / metabolism
  • Inflammation Mediators / physiology*
  • Interleukin-17 / genetics
  • Interleukin-17 / metabolism
  • Interleukin-6 / genetics
  • Interleukin-6 / metabolism
  • Male
  • Mice, Inbred DBA
  • NF-kappa B / metabolism
  • Signal Transduction
  • Toll-Like Receptor 4 / genetics
  • Toll-Like Receptor 4 / metabolism
  • Tumor Necrosis Factor-alpha / genetics
  • Tumor Necrosis Factor-alpha / metabolism
  • beta-Arrestin 2
  • beta-Arrestins
  • p38 Mitogen-Activated Protein Kinases / genetics
  • p38 Mitogen-Activated Protein Kinases / metabolism

Substances

  • Arrb2 protein, mouse
  • Arrestins
  • Inflammation Mediators
  • Interleukin-17
  • Interleukin-6
  • NF-kappa B
  • Tlr4 protein, mouse
  • Toll-Like Receptor 4
  • Tumor Necrosis Factor-alpha
  • beta-Arrestin 2
  • beta-Arrestins
  • Hyaluronic Acid
  • Cyclic AMP-Dependent Protein Kinases
  • p38 Mitogen-Activated Protein Kinases