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Serum factors potentiate hypoxia-induced hepatotoxicity in vitro through increasing transforming growth factor-beta1 activation and release.
- Source :
-
Cytokine [Cytokine] 2009 Jul; Vol. 47 (1), pp. 11-22. Date of Electronic Publication: 2009 May 19. - Publication Year :
- 2009
-
Abstract
- Background: Although transforming growth factor-beta (TGF-beta), a growth regulator of hepatocytes, induces cell death under pathological conditions, responsiveness of hepatocytes to hypoxic stimulus has not been fully defined. This study aimed at investigating the role of TGF-beta1 in hypoxia-induced hepatotoxicity using cultured clone-9 hepatocytes with or without serum supplementation.<br />Methods/results: Presence of serum significantly potentiated hypoxia-induced hepatotoxicity after 72h of exposure, as evidenced by fluorescent viability stain and LDH cytotoxicity assay. Quantitative PCR showed that TGF-beta1 gene expression decreased, while ELISA revealed that latent TGF-beta1 in conditioned media prominently increased in serum-treated groups under hypoxia. Western blotting indicated that both type I and II receptors of TGF-beta were up-regulated in serum-free groups, but down-regulated in serum-treated groups under hypoxia. Smad2 phosphorylation was only detectable in cells supplemented with serum, and hypoxia potentiated the extent of Smad2 phosphorylation, implicating that the activated TGF-beta1 induces hepatotoxicity in an autocrine manner. Addition of exogenous TGF-beta1 deteriorated, while TGF-beta1 blockade by neutralizing antibody ameliorated hypoxia-induced hepatotoxicity with serum supplementation. Gelatine zymography and immunofluorescent stain evidenced that elevated MMP-2 and MMP-9 activity and serum-dependent CD44 expression and its membranous localization may contribute to TGF-beta1 activation.<br />Conclusion: The results suggest that the mechanism governing TGF-beta activation plays a crucial role in hypoxia-induced hepatotoxicity. Thus, interventions on TGF-beta1 bioavailability and/or its cognate signaling may be of benefit in preventing hypoxia-related liver injuries.
- Subjects :
- Animals
Antibodies, Monoclonal immunology
Antibodies, Monoclonal pharmacology
Apoptosis drug effects
Cell Hypoxia drug effects
Cell Line
Cell Survival drug effects
Cell Survival physiology
Gene Expression physiology
Hepatocytes cytology
Hepatocytes drug effects
Hyaluronan Receptors metabolism
L-Lactate Dehydrogenase metabolism
Matrix Metalloproteinase 9 metabolism
Nitroimidazoles metabolism
Phosphorylation drug effects
Proliferating Cell Nuclear Antigen metabolism
Protein Serine-Threonine Kinases metabolism
Rats
Rats, Sprague-Dawley
Receptor, Transforming Growth Factor-beta Type I
Receptor, Transforming Growth Factor-beta Type II
Receptors, Transforming Growth Factor beta metabolism
Smad2 Protein metabolism
Transforming Growth Factor beta1 genetics
Transforming Growth Factor beta1 immunology
Transforming Growth Factor beta1 pharmacology
Apoptosis physiology
Cell Hypoxia physiology
Hepatocytes physiology
Serum physiology
Transforming Growth Factor beta1 metabolism
Subjects
Details
- Language :
- English
- ISSN :
- 1096-0023
- Volume :
- 47
- Issue :
- 1
- Database :
- MEDLINE
- Journal :
- Cytokine
- Publication Type :
- Academic Journal
- Accession number :
- 19457680
- Full Text :
- https://doi.org/10.1016/j.cyto.2009.03.004