Transformation-dependent @entity460 influx by voltage-operated XXXX channels in stellate cells of @entity35 liver.

@entity3692 @entity35 @entity409 @entity593 @entity460 @entity972 @entity141 @entity1810
BACKGROUND/AIMS: The transformation of hepatic stellate cells into myofibroblasts is a key step in the pathogenesis of fibrotic @entity409 . The intracellular signaling associated with hepatic stellate cell transformation becomes a point of interest, especially the role of cytosolic free @entity460 concentration ([ @entity141 ]i). The aim of the study was to investigate possible differences between various transformation phenotypes of hepatic stellate cells with regard to the @entity460 influx mediated by L-type voltage-operated @entity460 channels (L-type VOC). METHODS: Hepatic stellate cells were isolated from @entity35 liver by pronase-collagenase reperfusion and cultured under standard conditions. The transformation of hepatic stellate cells was stimulated by treatment with transforming growth factor-beta (TGF-beta) or inhibited with @entity3692 ( @entity3692 ) and characterized by immunocytochemistry for smooth muscle alpha-actin and determination of hyaluronan in the culture media with a ligand binding assay. [ @entity141 ]i was measured in individual cells with fluorescence microscopy using @entity593 . VOCs were activated by the standard procedure of extracellular @entity972 elevation, to achieve depolarization, and identified by various controls. RESULTS: In transformed myofibroblasts the activation of VOCs by @entity972 elevation from 5.4 mmol/l to 50.4 mmol/l led to a 19% increase in [ @entity141 ]i in contrast to 0.2% in hepatic stellate cells cultured for 3 days. In 7-day old hepatic stellate cells, after stimulation of cell transformation with @entity1810 , an enhanced [ @entity141 ]i response to @entity972 elevation was detected, while inhibition of transformation with @entity3692 for the same time caused a decreased @entity460 signal compared with untreated control cultures. Short-term treatment with the cytokines (1 day) did not influence depolarization-dependent @entity460 signals. CONCLUSION: The results show the [ @entity141 ]i increase via L-type VOCs to be dependent on the transformation level of hepatic stellate cells into myofibroblasts which can be influenced by the long-term treatment of hepatic stellate cells with TGF-beta or @entity3692 . In contrast, there is no evidence for direct regulation of VOC activity by TGF-beta or @entity3692 after short-term exposure.
