Fig 1: ORP8 overexpression enhances the 25-OHC effect on ER stress and apoptosis. A: HepG2 cells were transfected with ORP8, ORP5, ORP8△ORD cDNA, or empty vector, and the overexpression efficiency was assessed by Western blot analysis. B, C: HepG2 cells were transfected with ORP8, ORP5, and ORP8△ORD cDNA, and then treated with or without 10 μM 25-OHC for 24 h, and relative Bip and Chop mRNA levels were measured by qRT-PCR. ATF4, Chop, phospho-PERK, and phospho-eIF2α protein levels were analyzed by Western blotting. D: HepG2 cells were treated as indicated above, stained with annexin V-FITC and PI, and analyzed by flow cytometry for cell apoptosis. E: Cleaved caspase-9 and -3 protein levels were analyzed by Western blotting. The data represent mean ± SD from three individual experiments (n = 3, **P < 0.01, ***P < 0.001).