Fig. 3

The impact of recombinant human proteoglycan 4 (rhPRG4) treatment on interleukin-1 beta (IL-1β)-induced nuclear factor kappa b (NFκB) p50 and p65 nuclear translocation, inhibitor kappa B alpha (IκBα) phosphorylation and degradation. Data are presented as mean ± standard deviation of four independent experiments; *p < 0.001, **p < 0.01. a Impact of rhPRG4 treatment on IL-1β-induced p50 protein nuclear translocation in ostoarthritis fibroblast-like synoviocytes (OA FLS). IL1β treatment induced p50 protein nuclear translocation. rhPRG4 treatment (100 μg/ml and 200 μg/ml) inhibited IL-1β-induced p50 protein nuclear translocation. Co-incubation with a CD44 neutralizing monoclonal antibody (CD44 Ab) abolished the effect of rhPRG4 treatment. CD44 Ab treatment alone did not alter p50 nuclear translocation. b Impact of rhPRG4 treatment on IL-1β-induced p65 protein nuclear translocation in OA FLS. IL1β treatment induced p65 protein nuclear translocation. rhPRG4 treatment (100 μg/ml and 200 μg/ml) inhibited IL-1β-induced p65 protein nuclear translocation. Co-incubation with a CD44 neutralizing monoclonal antibody (CD44 Ab) abolished the effect of rhPRG4 treatment. CD44 Ab treatment alone did not alter p65 nuclear translocation. c Representative western blot of cytosolic phosphorylated inhibitor kappa B alpha (p-IκBα) in untreated and IL-1β-treated OA synoviocytes in the absence or presence of rhPRG4 and/or CD44 Ab. rhPRG4 (200 μg/ml) reduced p-IκBα levels in a CD44-dependent manner. d Representative western blot of cytosolic total inhibitor kappa B alpha (IκBα) in untreated and IL-1β-treated OA synoviocytes in the absence or presence of rhPRG4 and/or CD44 Ab. rhPRG4 (200 μg/ml) increased IκBα levels in a CD44-dependent manner