P240 - Resveratrol enriched Iksan526 callus extract induces dedifferentiation in chondrocytes via the ERK-1/2 and PI3K/Akt pathways
The resveratrol-enriched transgenic rice line Iksan526 was first developed by the Rural Development Administration of Korea using genetic engineering techniques, which shows beneficial health effects in mitigating metabolic syndrome and obesity. Moreover, Iksan526 callus extract (IS526) was shown to suppress skin melanogenesis in ultraviolet B-induced models. However, the effects of IS526 on the differentiation in chondrocytes, and the underlying mechanism have not been investigated in detail. In this study, the effects and cellular regulatory mechanisms of IS526 on rabbit articular chondrocytes were examined.
Methods and Materials
Following IS526 treatment, the expression n levels of inflammatory and differentiation-related proteins were detected via western blotting, Alcian blue staining, and immunofluorescence staining.
IS562 induced the loss of type II collagen and decreased sulfate proteoglycan levels in dose- and time-dependent manners. We further analyzed the effects of ISI526 on skeletogenesis in zebrafish larvae using alcian blue staining. IS526 also increased the phosphorylation of ERK and p38 kinase but inhibited the phosphorylation of Akt. Pharmacological inhibition of MMP-13 blocked the IS526-induced decrease in type II collagen levels. Moreover, Treatment with SB203580 (p38 kinase inhibitor) and LY294002 (PI-3K/Akt inhibitor) enhanced the suppression of type II collagen but PD98059 (ERK-1/-2 inhibitor) rescued IS526-induced dedifferentiation.
These results suggest that IS526 regulates type II collagen, MMP-13, via the MAPK and PI-3K/Akt pathways in rabbit articular chondrocytes.