Actin filament formation, reorganization and migration are impaired in hepatic stellate cells under influence of trichostatin A, a histone deacetylase inhibitor.
OBJECTIVE
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.
Rombouts
Krista
K
Laboratory for Molecular Liver Cell Biology, Faculty of Medicine and Pharmacy, Free University of Brussels (VUB), Laarbeeklaan 103, 1090 Brussels, Belgium. krom@cyto.vub.ac.be
Knittel
Thomas
T
Machesky
Laura
L
Braet
Filip
F
Wielant
Annemie
A
Hellemans
Karine
K
De Bleser
Pieter
P
Gelman
Irwin
I
Ramadori
Giuliano
G
Geerts
Albert
A
D008841:Actin Cytoskeleton / Q000187:drug effects / Q000502:physiology*; D051377:Actin-Related Protein 2; D051378:Actin-Related Protein 3; D000199:Actins / Q000378:metabolism; D000818:Animals; D002465:Cell Movement / Q000187:drug effects; D003598:Cytoskeletal Proteins / Q000378:metabolism; D003893:Desmin / Q000378:metabolism; D019332:Endothelin-1 / Q000494:pharmacology; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D020869:Gene Expression Profiling; D005904:Glial Fibrillary Acidic Protein / Q000378:metabolism; D056572:Histone Deacetylase Inhibitors; D006706:Homeostasis; D006877:Hydroxamic Acids / Q000494:pharmacology*; D008099:Liver / Q000166:cytology / Q000187:drug effects / Q000502:physiology*; D008297:Male; D016133:Polymerase Chain Reaction / Q000379:methods; D051381:Rats; D017208:Rats, Wistar; D014746:Vimentin / Q000378:metabolism
D051377:Actin-Related Protein 2; D051378:Actin-Related Protein 3; D000199:Actins; D003598:Cytoskeletal Proteins; D003893:Desmin; D019332:Endothelin-1; D004791:Enzyme Inhibitors; D005904:Glial Fibrillary Acidic Protein; D056572:Histone Deacetylase Inhibitors; D006877:Hydroxamic Acids; D014746:Vimentin; C012589:trichostatin A