Evaluation of intracellular signalling pathways in response to insulin-like growth factor I in apoptotic-resistant activated human hepatic stellate cells.

Background: Human hepatic stellate cells have been shown to be resistant to apoptotic stimuli. This is likely dependent on the activation of anti-apoptotic pathways upon transition of these cells to myofibroblast-like cells. In particular, previous studies have demonstrated an increased expression of the anti-apoptotic protein Bcl-2 and a decreased expression of the pro-apoptotic protein Bax during the transition of the hepatic stellate cell phenotype from quiescent to myofibroblast-like cells.

MARCKS is a downstream effector in platelet-derived growth factor-induced cell motility in activated human hepatic stellate cells.

Myristoylated alanine-rich protein kinase c substrate (MARCKS) has been suggested to be implicated in cell adhesion, secretion, motility and mitogenesis through regulation of the actin cytoskeletal structure. In the present study, a possible link between MARCKS and the platelet-derived growth factor (PDGF) signaling pathway was investigated in activated human hepatic stellate cells (hHSC), critical regulators of hepatic fibrogenesis. PDGF-BB stimulation resulted in a bi-directional movement of MARCKS that coincided with the phosphorylation of MARCKS and the activation of both PKCepsilon and PKCalpha.

Thiazolidinedione treatment inhibits bile duct proliferation and fibrosis in a rat model of chronic cholestasis.

Aim: To investigate the effects of troglitazone (TGZ), an anti-diabetic drug which activates peroxisome proliferator-activated receptor-gamma (PPAR-gamma), for liver tissue repair, and the development of ductular reaction, following common bile duct ligation (BDL) in rats.

Methods: Rats were supplemented with TGZ (0.2% w/w in the pelleted food) for 1 wk before BDL or sham operation.

Cell adhesion regulates platelet-derived growth factor-induced MAP kinase and PI-3 kinase activation in stellate cells.

The biologic effects of growth factors are dependent on cell adhesion, and a cross talk occurs between growth factors and adhesion complexes. The aim of the present study was to evaluate the influence of cell adhesion on the major intracellular signaling pathways elicited by platelet-derived growth factor (PDGF) in hepatic stellate cells (HSC). PDGF signaling was investigated in an experimental condition characterized by lack of cell adhesion for different intervals of time.