ABCG1 Attenuates Oxidative Stress Induced by H₂O₂ through the Inhibition of NADPH Oxidase and the Upregulation of Nrf2-Mediated Antioxidant Defense in Endothelial Cells

Figure 5

Effect of intracellular cholesterol accumulation on prooxidant NADPH oxidase activity and antioxidant HO-1 expression. (a) HUAECs were transfected with the specific ABCG1 siRNA or ABCG1 overexpression plasmid or preincubated with T0901317 and then treated with H₂O₂ or not. Intracellular total cholesterol contents were measured by a microenzymatic fluorescence assay. (b) Intracellular total cholesterol contents were measured after cholesterol repletion or cholesterol depletion using cholesterol-loaded cyclodextrin (CD) or MβCD in HUAECs. (c) NADPH oxidase activity was detected after cholesterol repletion or cholesterol depletion in HUAECs. (d) HO-1 mRNA expression was measured by real-time PCR after cholesterol repletion and cholesterol depletion in HUAECs. Data shown are (). and vs. controls; ^# and vs. HUAECs incubated with H₂O₂.

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