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In vitro and in vivo activation of rat hepatic stellate cells results in de novo expression of L‐type voltage‐operated calcium channels
Author(s) -
Bataller Ramón,
Gasull Xavier,
Ginès Pere,
Hellemans Karine,
Görbig M. Nieves,
Nicolás Josep M.,
SanchoBru Pau,
Heras Dara De Las,
Gual Arcadi,
Geerts Albert,
Arroyo Vicente,
Rodés Juan
Publication year - 2001
Publication title -
hepatology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.488
H-Index - 361
eISSN - 1527-3350
pISSN - 0270-9139
DOI - 10.1053/jhep.2001.23500
Subject(s) - hepatic stellate cell , in vivo , biology , voltage dependent calcium channel , medicine , microbiology and biotechnology , chemistry , endocrinology , calcium
Following chronic liver injury, hepatic stellate cells (HSCs) transdifferentiate into myofibroblast‐like cells, which develop contractile properties and contribute to increased resistance to blood flow. We investigated whether this phenotypic activation includes changes in the expression of L‐type voltage‐operated Ca 2+ channels (VOCC), which mediate Ca 2+ influx and regulate cell contraction in vascular cell types. Rat HSCs were studied in the quiescent phenotype and after their activation in vitro (cultured on plastic for 14 days) and in vivo (isolated from rats with CCl 4 ‐induced cirrhosis). Patch‐clamp studies showed Ca 2+ currents through L‐type VOCC in HSCs activated both in vitro and in vivo , whereas no currents were detected in quiescent HSCs. Moreover, binding studies with 3 H‐isradipine, a specific L‐type VOCC antagonist, showed a large number of binding sites in activated HSCs, while no specific binding was found in quiescent HSCs. Finally, messenger RNA (mRNA) encoding L‐type VOCC was not detected in quiescent HSCs as assessed by reverse transcription‐polymerase chain reaction (RT‐PCR) and Northern blot analysis, whereas it was present in activated HSCs. Stimulation of L‐type VOCC with KCl resulted in a marked increase in [Ca 2+ ] i followed by cell contraction in HSCs activated both in vitro and in vivo , whereas no effects were observed in quiescent HSCs. We conclude that the activation of HSCs is associated with up‐regulation of L‐type VOCC that mediate Ca 2+ influx and cell contraction. These results may be relevant to the pathogenesis of portal hypertension.