Effects of N-acetylcysteine and L-Cysteine on TGF-beta Signaling in Culture-activated Hepatic Stellate Cells

Due to its profibrogenic actions, TGF-beta1 and the subsequent steps of the TGF-beta1 induced signaling cascade are prefered targets for antifibrogenic therapies. The fact that Smad-dependent TGF-beta signaling is modulated by reactive oxygen species (ROS) prompted us to investigate the influence of L-cysteine and its derivative N-acetylcysteine (NAC), a scavenger of ROS and precursor of glutathion, on TGF-beta signaling in culture-activated hepatic stellate cells (HSC). In a previous study, we have shown that NAC is able to block TGF-beta? signaling in HSC, but is ineffective when the signal is transduced throu…