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Shengzhou Wu, Lin Sun, Jingjing Cai, Jia Qu; Low Doses Of Proteasome Inhibitors Protect Against Oxidative Injuries Via Ppar(α)-dependent Pathway In Arpe-19 Cells. Invest. Ophthalmol. Vis. Sci. 2012;53(14):6490.
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Oxidative processes have been proposed to play important roles in age-related macular degeneration (AMD). Evidences indicated that the proteasomal degradation pathway protects cells against oxidative stresses. Previous report showed that low doses of proteasome inhibitors reduce injury from oxidative damage in neuronal cultures via increasing proteasome activities. The objective of this study was to determine whether low doses of proteasome inhibitors could save ARPE-19 cells from oxidative stresses and its associated mechanisms.
The protective effects of low doses of reversible or irreversible proteasome inhibitors in ARPE-19 cells were assessed by MTS assay. The same method was also applied to test the effect of PPARalpha or PPARgamma antagonists on the protective effects of MG-132 or clasto-lactacystinβ-lactone. PPAR response element (PPRE) transactivity in ARPE-19 cells induced by low doses of proteasome inhibitors was assayed by dual-luciferase assay. Electrophoretic mobility shift assay(EMSA) was employed to confirm the results of dual-luciferase. Super-shift analysis was used to detect the category of PPAR transcriptional factors activated by low doses of MG-132 or clasto-lactacystinβ-lactone.
Exposure to low concentrations of MG-132 or clasto-lactacystinβ-lactone protected against oxidative damage by vitamine k3 (VK3) or 4- hydroxynonenal (4-HNE) in ARPE-19 cells. The selective PPARα antagonist GW6471 prevented this protective effect while the PPARγ antagonist GW9662 did not. Dual-luciferase assay indicated that proteasome inhibitors stimulated PPAR response element (PPRE) transactivity in a concentration-dependent manner. The result of EMSA was consistent with luciferase assay, and super-shift analysis showed proteasome inhibitors mainly induced PPARα.
our data suggest that low doses of proteasome inhibitors-pre-treated cultures are resistant to oxidative damage in ARPE-19 cells and this protective mechanism is possibly via PPARα-dependent pathway.Support: Zhejiang Province Natural Science foundation (Y2110086) and Wenzhou Medical College (89210001).
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