Fig. 4.

HNP1 employs LDLR to shuttle LDL into the liver. (A–E) Uptake of human LDL by HepG2 cells. (A/B) HepG2 cells were treated with human LDL (50 μg/ml) in presence or absence of HNP1 (1 μg/ml) for 2 h and LDL uptake was quantified following Oil Red O elution. Representative images for Oil Red O staining are shown in (B). 40 × magnification. (C) HepG2 cells were treated with heparinase I and III (1 U/ml, 1 h) or vehicle prior to exposure to LDL. (D/E) Lrp1 (D) or Ldlr (E) were silenced by use of siRNA prior to LDL treatment. (F–H) The portal vein of wild type (WT) or Ldlr^−/− mice was cannulated and perfused with human Dil-LDL preincubated with HNP1 (10 μg/ml) or PBS. Livers were minced and analyzed by flow cytometry. (F) Representative histograms of Dil-LDL fluorescence in WT mice. (G) Quantification of Dil-LDL uptake relative to background fluorescence (ctrl) which was set to 1. n = 3 per group, data were analyzed by Mann-Whitney test. (H) Confocal microscopy of liver sections from WT mice perfused with Dil-LDL preincubated with PBS or HNP1. Scale bar represents 10 μm.