Actin filament formation, reorganization and migration are impaired in hepatic stellate cells under influence of trichostatin A, a histone deacetylase inhibitor

Background/Aims: Previously, trichostatin A (TSA), a histone deacetylase inhibitor, has been shown to exhibit strong antifibrotic characteristics in hepatic stellate cells (HSC), which are known to play a central role in chronic liver diseases. TSA retained a more quiescent phenotype in spite of culture conditions that favor transdifferentiation into activated HSC. Methods: To identify TSA-sensitive genes, differential mRNA display, Northern and Western blot analysis were used and genes were functionally validated by using contraction and motility assays. Results: TSA prevented new actin filament formation by down-regulation of two nucleating proteins, actin related protein 2 (Arp2) and Arp3, and by up-regulation of adducin like protein 70 (ADDL70) and gelsolin, two capping proteins. RhoA, a key mediator in the development of the actin cytoskeleton, decreased following TSA exposure. Expression of proteins of Class III intermediate filaments was affected by TSA. Furthermore, F-actin and G-actin were expressed heterogeneously under influence of TSA. Functionally, TSA treatment abrogated migration of quiescent HSC, while migration was reduced in transitional HSC. The endothelin-1-induced contractility properties of HSC was not affected by TSA. Conclusions: These data indicate that TSA affects the development of the actin cytoskeleton in quiescent HSC and thereby abrogates the process of HSC transdifferentiation.