Expression and function of fibroblast growth factor (FGF) 9 in hepatic stellate cells and its role in toxic liver injury

• Published in: Biochemical and biophysical research communications 2007-09, Vol.361 (2), p.335-341
• Main Authors: Antoine, Marianne, Wirz, Werner, Tag, Carmen G., Gressner, Axel M., Marvituna, Meltem, Wycislo, Mathias, Hellerbrand, Claus, Kiefer, Paul
• Format: Article
• Language: English
• Subjects: 60 APPLIED LIFE SCIENCES; Animals; BIOLOGICAL REPAIR; CARBON TETRACHLORIDE; CELL PROLIFERATION; Cells, Cultured; Cercopithecus aethiops; Chemical and Drug Induced Liver Injury; COS Cells; DNA; DNA - biosynthesis; Enzyme Activation; Fibroblast Growth Factor 2 - metabolism; Fibroblast growth factor 9; Fibroblast Growth Factor 9 - genetics; Fibroblast Growth Factor 9 - metabolism; FIBROBLASTS; GROWTH FACTORS; Hepatic stellate cells (HSC); Hepatocytes - enzymology; Hepatocytes - metabolism; Humans; In Vitro Techniques; INJURIES; LIVER; LIVER CELLS; Liver Diseases - metabolism; Male; Mesenchymal–epithelial cell signaling; Mitogen-activated protein kinase (MAPK); Mitogen-Activated Protein Kinase 1 - metabolism; Mitogen-Activated Protein Kinase 3 - metabolism; Mitogens - metabolism; PHOSPHORYLATION; PHOSPHOTRANSFERASES; Protein Isoforms - genetics; Protein Isoforms - metabolism; Rats; Rats, Sprague-Dawley; RECEPTORS; Receptors, Fibroblast Growth Factor - genetics; Receptors, Fibroblast Growth Factor - metabolism; REGENERATION; SUBSTRATES; THYMIDINE; TOXICITY; Up-Regulation - genetics
• ISSN: 0006-291X; 1090-2104
• DOI: 10.1016/j.bbrc.2007.06.189

Hepatic injury and regeneration of the liver are associated with activation of hepatic stellate cells (HSC). Fibroblast growth factors (FGFs) and their receptors are important regulators of repair in various tissues. HSC express FGFR3IIIc as well as FGFGR4 and different spliced FGFR1IIIc and FGFR2IIIc isoforms which differ in the presence or absence of the acid box and of the first Ig-like domain. Expression of FGF9, known to be capable to activate the HSC FGFR2/3-isoforms, was increased in HSC in liver slice cultures after exposition to carbon tetrachloride, as an acute liver injury model. FGF9 significantly stimulated 3-H thymidine incorporation of hepatocytes, but failed to induce DNA synthesis in HSC despite the fact that FGF9 induced a sustained activation of extracellular signal-related kinases (ERK) 1/2. FGF9 induced an increased phosphorylation of Tyr436 of the fibroblast growth factor receptor substrate (FRS) 2, while phosphorylation of Tyr196 which is required for efficient Grb2 recruitment remained unchanged. Our findings suggest that HSC FGF9 provide a paracrine mitogenic signal to hepatocytes during acute liver injury, while the autocrine FGF9 signaling appears to be not sufficient to induce cell proliferation.