Figure 5

Curcumin suppresses IL-1β-induced apoptotic and inflammatory responses in monolayers of MSCs in a concentration dependent manner. Monolayer cultures of MSCs were pre-stimulated for four hours with various concentrations of curcumin (0, 0.5, 1, 2 and 5 μM) followed by 24 h incubation with IL-1β, and Western blotting was performed using whole cell lysates and nuclear extracts. A: A strong dose dependent effect on IL-1β induced activation of caspase-3 and COX-2 was observed. Curcumin concentrations as low as 0.5 μM suppresses IL-1β induced activation of caspase-3 and COX-2. Higher concentrations of curcumin completely inhibited IL-1β induced activation of caspase-3 and production of COX-2. This was confirmed by quantitative densitometry. The mean values and standard deviations from three independent experiments are shown. Expression of the housekeeping gene β-actin was not affected. B: Curcumin exerts a strong dose dependent effect on IL-1β activated Iκ-Bα in MSCs, by suppressing phosphorylation of Iκ-Bα (which is already fairly robust) and NF-κB nuclear translocation at 0.5 μM curcumin. Higher concentrations of curcumin blocked IL-1β-induced activation of Iκ-Bα and NF-κB translocation to the nucleus completely. This was confirmed by quantitative densitometry. The mean values and standard deviations from three independent experiments are shown. Expression of the housekeeping gene β-actin and the DNA repair enzyme PARP were not affected.