The complex effects of the slow-releasing hydrogen sulfide donor GYY4137 in a model of acute joint inflammation and in human cartilage cells.
Bottom Line: We have now assessed the effect of GYY4137 (a slow-releasing H2 S donor) on lipopolysaccharide (LPS)-evoked release of inflammatory mediators from human synoviocytes (HFLS) and articular chondrocytes (HAC) in vitro.GYY4137 (0.1-0.5 mM) decreased LPS-induced production of nitrite (NO2 (-) ), PGE2 , TNF-α and IL-6 from HFLS and HAC, reduced the levels and catalytic activity of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) and reduced LPS-induced NF-κB activation in vitro.In the CFA-treated mouse, GYY4137 (50 mg/kg, i.p.) injected 1 hr prior to CFA increased knee joint swelling while an anti-inflammatory effect, as demonstrated by reduced synovial fluid myeloperoxidase (MPO) and N-acetyl-β-D-glucosaminidase (NAG) activity and decreased TNF-α, IL-1β, IL-6 and IL-8 concentration, was apparent when GYY4137 was injected 6 hrs after CFA.
Affiliation: Pharmaceutical Science Research Division, King's College London, London, England.Show MeSH
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Mentions: We next examined the effects of GYY4137 on NF-κB activation in HFLS and HAC. Treatment of cells with GYY4137 for 1 hr prior to LPS stimulation significantly reduced NF-κB activation in HFLS (Fig. 4A) and HAC (Fig. 4B). Significant inhibition of NF-κB activation was also observed in HFLS (Fig. 4A) and HAC (Fig. 4B) when GYY4137 was added to cells 4 hrs post-LPS treatment although this inhibitory effect was much less marked. This effect of GYY4137 was mimicked by PPM-18 (classical inhibitor of NF-κB activation) although GYY4137 was less effective. Although treatment of HFLS with a cytokine cocktail (containing 10 ng/ml each of TNF-α and IFN-γ with 1 ng/ml IL-1β) for up to 2 hrs resulted in IκBα phosphorylation and degradation of IκBα (Fig. 4C), further Western blotting analysis (Fig. 4D) revealed that GYY4137 did not reduce the cytokine cocktail-induced IκBα degradation or phosphorylation.
Affiliation: Pharmaceutical Science Research Division, King's College London, London, England.