Alpha B-crystallin expression in human and rat hepatic stellate cells

Background/Aims: We searched for factors implicated in early hepatic stellate cell (HSC) activation in diseased liver, by means of suppression subtractive hybridization (SSH). Methods: SSH was performed between messenger RNA (mRNA) from normal rat HSC and mRNA from HSC, isolated from rats with acute D-galactosamine (Gal)-induced hepatitis. Results: One of the potentially upregulated factors which we found was alpha B-crystallin (ABCRYS), a small heat-shock protein and a chaperone known to protect the cell against protein degradation in conditions of cellular stress and known to associate with various types of intermediate filaments. Upregulation of ABCRYS mRNA in HSC, following Gal-intoxication (3.5-fold) as well as by culturing the HSC on plastic (20-30-fold), was confirmed by quantitative realtime reverse transcription polymerase chain reaction. The expression of ABCRYS protein in human and rat HSC was demonstrated by immunohistochemistry, in vitro and in vivo, in normal and diseased liver. Double-staining co-localized ABCRYS immunoreactivity with alpha-smooth muscle actin immunoreactivity in human liver and with desmin immunoreactivity in rat liver. In vivo upregulation of ABCRYS protein following Gal-intoxication was also shown, by comparison with desmin expression. Conclusions: Human and rat HSC express ABCRYS mRNA and protein. Both are rapidly upregulated following HSC activation. (C) 2001 European Association for the Study of the Liver. Published by Elsevier Science B.V. All rights reserved.