Abstract
Peroxisome proliferator-activated receptor-α (PPAR-α) is a transcription factor and has been reported to inhibit cisplatin-mediated proximal tubule cell death. In addition, doxorubicin (Adriamycin)-induced nephrosis in rats is a commonly used experimental model for pharmacological studies of human chronic renal diseases. In this study, we investigated the protective effect of PPAR-α on doxorubicin-induced apoptosis and its detailed mechanism in NRK-52E cells and animal models. The mRNA level of PPAR-α was found to be reduced by doxorubicin treatment in NRK-52E cells. PPAR-α overexpression in NRK-52E cells significantly inhibited doxorubicin-induced apoptosis and the quantity of cleaved caspase-3. Endogenous prostacyclin (PGI2) augmentation, which has been reported to protect NRK-52E cells from doxorubicin-induced apoptosis, induced the translocation and activation of PPAR-α. The transformation of PPAR-α short interfering RNA was applied to silence the PPAR-α gene, which abolished the protective effect of PGI2 augmentation in doxorubicin-treated cells. To confirm the protective role of PPAR-α in vivo, PPAR-α activator docosahexaenoic acid (DHA) was administered to doxorubicin-treated mice, and it has been shown to significantly reduce the doxorubicin-induced apoptotic cells in renal cortex. However, this protective effect of DHA did not exist in PPAR-α-deficient mice. In NRK-52E cells, the overexpression of PPAR-α elevated the activity of catalase and superoxide dismutase and inhibited doxorubicin-induced reactive oxygen species (ROS). PPAR-α overexpression also inhibited the doxorubicin-induced activity of nuclear factor-κB (NF-κB), which was associated with the interaction between PPAR-α and NF-κB p65 subunit as revealed in immunoprecipitation assays. Therefore, PPAR-α is capable of inhibiting doxorubicin-induced ROS and NF-κB activity and protecting NRK-52E cells from doxorubicin-induced apoptosis.
Footnotes
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This study was supported by National Science Council, Taipei, Taiwan.
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H.L. and C.-F.C. contributed equally to the work.
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Article, publication date, and citation information can be found at http://molpharm.aspetjournals.org.
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doi:10.1124/mol.107.037523.
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ABBREVIATIONS: PPAR, peroxisome proliferator-activated receptor; PGI2, prostacyclin; DHA, docosahexaenoic acid; ROS, reactive oxygen species; NF-κB, nuclear factor-κB; siRNA, short interfering RNA; PG, prostaglandin; COX, cyclooxygenase; PGIS, prostacyclin synthase; DMEM, Dulbecco's modified Eagle's medium; GAPDH, glyceraldehyde-3-phosphate dehydrogenase; PCR, polymerase chain reaction; HPGK, human phosphoglycerate kinase; MCD, malonyl-CoA decarboxylase; β-gal, β-galactosidase; TUNEL, terminal deoxynucleotidyl transferase dUTP nick-end labeling; DAPI, 4′-6-diamidino-2-phenyindole; TNF-α, tumor necrosis factor-α; ELISA, enzyme-linked immunosorbent assay; DCF, 2′7′-dichlorofluorescein; EMSA, electrophoretic mobility shift assay; m.o.i., multiplicity of infection.
- Received April 27, 2007.
- Accepted August 1, 2007.
- The American Society for Pharmacology and Experimental Therapeutics
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