Figure 1.

Dscr-1 deficiency induces oxidative and ER stress and SREBP2 hyperactivation in the liver.A, X-gal staining in the liver from DSCR-1-lacZ-hprt reporter mice crossed with ApoE^−/− (upper) or treated with LPS for 24 h (lower). B, representative liver sections of immunohistochemical staining using anti-Dscr-1 antibody from WT and ApoE^−/− mice. Brown color indicates Dscr-1-positive hepatocyte with hematoxylin counterstaining. Scale bar: 50 μm. Right bar graph shows quantitative analysis of Dscr-1-positive area (n = 6, mean ± SD) ∗p < 0.01 compared with WT. C, real-time qPCR analysis of mouse Dscr-1 short variant mRNA from lung or liver endothelium (n = 3, mean ± SD). ∗p < 0.001 compared with endothelial cells from lung in WT mice. D and E, western blots of HepG2 cells treated with si-DSCR-1 compared with si-control in the presence or absence of cholesterol-starved medium (D). Western blots of primary cultured hepatocytes from WT or Dscr-1^−/− mice (E). Membrane/cytosol fraction or nuclear fraction incubated with anti-SREBP2 or -LDLR antibodies. β-Actin or histone H3 shown as the loading control. Data are representative of three independent experiments. F, immunostaining of 4-HNE (indicated in brown) in liver sections from WT, Dscr-1^−/−, ApoE^−/−, or combined loss of Dscr-1 plus ApoE mice. Low magnification (left) and high magnification image (right) from each rectangle are shown, derived from four independent optimal fields in three independent experiments. Scale bar; 100 μm. G, western blots of HepG2 cells treated with si-DSCR-1 compared with si-control and with tunicamycin (TM), thapsigargin (TG), or mock control (DMSO). ER stress markers ATF-4, ATF-6a, and XBP-1S are also shown. Histone H3 indicates the loading control. Data shown are representative of three independent experiments.