4-THIAZOLIDINONE-BASED DERIVATIVES RESCUE TNAΑ-INHIBITED OSTEOBLAST DIFFERENTIATION IN MOUSE MESENCHYMAL PRECURSOR CELLS

Rheumatoid arthritis (RA) is an autoimmune inflammatory disease of yet unknown etiology. Tumor necrosis factor α (TNFα) is recognized as a regulatory substance that plays a central role in RA development and progression. On the other side, the bone morphogenetic protein (BMP) and Wnt signaling pathways are key mechanisms that induce and support cartilage and bone formation and maintenance. Previous studies showed that the pro-inflammatory cytokines TNFα and interleukin 1β (IL-1β) are central players in the inhibition of activity of skeletogenesis. The aim of this study was to evaluate the anti-inflammatory activity of novel 4-thiazolidinone-based derivatives towards TNFα–induced pro-inflammatory effects during bone formation. We performed in vitro evaluation of functional effects of 4-thiazolidinones denoted as Les-4368, Les-4370, Les-3882 and Les-3288 that were used in different doses (0.02, 0.1, 0.3 and 1.0 μM) on the TNFα-mediated inhibition of the BMP-induced osteoblast differentiation in mouse mesenchymal precursor (stem) cells of C2C12 line. Treatment of these cells with TNFα completely inhibited their myogenic differentiation, as well as strongly inhibited the BMP-induced osteogenesis. Strikingly, the treatment of C2C12 cells with Les-4368 and Les-3882 rescued the osteoblast differentiation from negative control of TNFα, and, moreover, converted this cytokine from the inhibitor of osteogenesis into its stimulator. Western-blot analysis of Inhibitory κBα (I-κBα) degradation was used to elucidate a mechanism of the anti-inflammatory effects. Les-3882 was more active, and it stimulated osteoblast differentiation at low dose (0.1 μM), presumably, via modulation of the NF-κB signaling pathway.