Abstract
Age-related progressive glomerular sclerosis in the rat is associated with increased expression of tumor necrosis factor-β1 and increased protein content in the renal cortex, enhanced production of H2O2, in both renal glomeruli and mesangial cells (MCs) cultured from them, as well as augmented glomerular oxidative damage. We have previously shown that tretinoin-treated old male Fischer 344 rats have 30% lower protein content in the renal cortex than control old rats. Here, we report that this effect may depend on the inhibition of the expression of tumor necrosis factor-β1, a matrigenic cytokine, and osteopontin, a protein with cell adhesive and chemotactic properties. In addition, we show that tretinoin prevents the cytotoxicity of H2O2 in cultured human MCs by increasing both the catalase activity and the reduced glutathione content, which are dose- and time-dependent changes. These increases were not dependent on each other: when these effects were previously inhibited with 3-amino-1,2,4-atriazole orl-buthionine-(S,R)-sulfoximine, respectively, tretinoin still induced the increase of the other noninhibited antioxidant defense. An enhanced gene transcription is the most likely mechanism involved in the tretinoin-induced stimulation of MC antioxidant defense systems because 1) preincubation of MCs with actinomycin D or cycloheximide fully abolished it; 2) tretinoin-incubated MCs showed increased levels of catalase mRNA and γ-glutamyl-cysteine synthetase (catalytic subunit) mRNA, the latter being the rate-limiting step in de novo reduced glutathione synthesis; and 3) the stability of both mRNA was unchanged by tretinoin. These results show one strategy of protecting renal cells from H2O2-mediated injury based on increasing their antioxidant defenses.
Footnotes
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Send reprint requests to: Dr. Francisco Javier de Lucio Cazaña, Profesor Titular, Departamento de Fisiologı́a, Facultad de Medicina, Universidad de Alcalá, Alcalá de Henares, Madrid, Spain. E-mail fffjlc{at}fisfar.alcala.es
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↵1 This work has been supported by Grant 97/0485 from the Spanish Fondo de Investigaciones Sanitarias and by a grant from the Fundacion Eugenio Rodriguez Pascual. V.M. has a research grant from the Consejo Social de la Universidad de Alcalá, and A.M. received financial support from the FINNOVA program (Comunidad Autonoma de Medrid).
- Abbreviations:
- BSO
- l-buthionine-(S,R)-sulfoximine
- GAPDH
- glyceraldehyde-3-phosphate dehydrogenase
- SSC
- standard saline citrate
- γ-GCS
- γ-glutamyl-cysteine synthetase
- GSH
- reduced glutathione
- LDH
- lactate dehydrogenase
- MTT
- 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide
- RT
- reverse transcription
- MC
- mesangial cell
- NAC
- N-acetylcysteine
- OP
- osteopontin
- PCR
- polymerase chain reaction
- TGF-β1
- transforming growth factor-β1
- Received August 13, 1998.
- Accepted October 29, 1998.
- The American Society for Pharmacology and Experimental Therapeutics
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