Fig. 5From: Curcumin synergizes with resveratrol to stimulate the MAPK signaling pathway in human articular chondrocytes in vitroMolecular model outlining the proposed mechanism for the stimulatory effects of resveratrol and curcumin on IL-1β- or U0126-induced MAPK pathway inhibition and apoptosis in primary chondrocytes in vitro. Signal transduction through β1-integrins leads to the activation of the Ras-MAP Kinase signaling pathway. Activation of the MAPK pathway may be one of the mechanisms by which β1-integrins regulate chondrocyte gene expression. Previous studies have shown that activation of the MAPK pathway regulates the activity of a number of intracellular signaling proteins through phosphorylation. Erk1/Erk2, a downstream kinase of the MAPK pathway, regulates the expression and activity of various transcription factors. Specific inhibition of Erk1/Erk2 by U0126 or IL-1β results in cleavage of caspase-3 in human chondrocytes in vitro. Since activation of caspase-3 and DNA fragmentation are common features of apoptosis, the specific inhibition of the Ras-mitogen-activated kinase leads to chondrocyte apoptosis. Resveratrol and curcumin both block the inhibition effect of U0126 or IL-1β on the MAPK pathway in chondrocytesBack to article page