Retroviral gene transfer of signaling molecules into murine fetal hepatocytes defines distinct roles for the STAT3 and ras pathways during hepatic development.
We recently demonstrated that oncostatin M (OSM) in the presence of glucocorticoid promotes development of fetal hepatic cells in a primary culture system. Our results also suggested that OSM transduces differentiation signals through gp130, a common subunit of the interleukin (IL)-6 family cytokine receptors. However, an essential downstream pathway required for hepatic development remains unknown. To address this issue, we expressed signal molecules by a retroviral expression vector in primary fetal hepatic cells and investigated a signaling pathway essential for OSM-mediated hepatic development. Expression of a dominant-negative form of STAT3 (DeltaSTAT3), but not DeltaSTAT5, suppressed differentiated phenotypes of hepatocytes induced by OSM. On the other hand, dominant-negative forms of Ras (RasN17) and SHP-2(C463A) rather augmented the expression of hepatic differentiation markers, suggesting that the Ras pathway negatively regulates hepatic development. Consistently, expression of a constitutively activated form of Ras (RasV12) inhibited cellular responses to OSM. Our results indicate that STAT3 is an essential signaling component for OSM-induced hepatic development, while activation of Ras appears to negatively regulate this process. Thus, retrovirus-mediated gene transfer is an effective means to analyze function of a gene in primary fetal hepatic culture.
Ito
Y
Y
Institute of Molecular and Cellular Biosciences, University of Tokyo, Tokyo, Japan.
Matsui
T
T
Kamiya
A
A
Kinoshita
T
T
Miyajima
A
A
D000818:Animals; D015415:Biomarkers; D002454:Cell Differentiation / Q000502:physiology; D002867:Chromones / Q000494:pharmacology; D004268:DNA-Binding Proteins / Q000502:physiology*; D005314:Embryonic and Fetal Development; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005333:Fetus / Q000502:physiology; D015870:Gene Expression; D018014:Gene Transfer Techniques; D005822:Genetic Vectors; D022781:Hepatocytes / Q000502:physiology*; D008099:Liver / Q000166:cytology / Q000196:embryology*; D051379:Mice; D009025:Morpholines / Q000494:pharmacology; D053683:Oncostatin M; D010455:Peptides / Q000502:physiology; D000081082:Phosphoinositide-3 Kinase Inhibitors; D012190:Retroviridae / Q000235:genetics*; D050796:STAT3 Transcription Factor; D015398:Signal Transduction / Q000502:physiology*; D015534:Trans-Activators / Q000502:physiology*; D019076:Transgenes / Q000235:genetics; D018631:ras Proteins / Q000502:physiology*
D015415:Biomarkers; D002867:Chromones; D004268:DNA-Binding Proteins; D004791:Enzyme Inhibitors; D009025:Morpholines; C508352:Osm protein, mouse; D010455:Peptides; D000081082:Phosphoinositide-3 Kinase Inhibitors; D050796:STAT3 Transcription Factor; C494087:Stat3 protein, mouse; D015534:Trans-Activators; D053683:Oncostatin M; C085911:2-(4-morpholinyl)-8-phenyl-4H-1-benzopyran-4-one; D018631:ras Proteins