Fig. 1. Silencing hepatocyte tPA increases apoB-lipoprotein cholesterol and apoB independently of LDLR or apoE.

(A) Ldlr^−/− mice were treated with AAV8-H1-shPlat (sh-tPA) or AAV8-H1-scrambled control (scr) and then fed the WD for 8 weeks. The livers were assayed for tPA protein, and plasma samples were assayed for total cholesterol and apoB-100 concentrations and for FPLC profiles of cholesterol, triglyceride, and apoB-100 (n = 9 to 10 mice per group). (B) Apoe^−/− mice were treated with AAV8-H1-shPlat (sh-tPA) or AAV8-H1-scrambled control (scr) and then fed the WD for 8 weeks. The livers were assayed for tPA protein, and plasma samples were assayed for total cholesterol and apoB-100 concentrations and for FPLC profiles of cholesterol, triglyceride, and apoB-100 (n = 5 mice per group). (C) Plat^fl/fl mice were treated with AAV8-TBG-cre (Cre) or AAV8-TBG-GFP (GFP) and then fed the WD for 8 weeks. The livers were assayed for tPA protein, and plasma samples were assayed for total cholesterol and apoB-100 concentrations and for FPLC profiles of cholesterol, triglyceride, and apoB-100. The cholesterol in the VLDL fractions is shown in a zoomed-in smaller graph (n = 6 mice per group). (D) Human primary hepatocytes were treated with siRNA against tPA mRNA (si-tPA) or scrambled RNA for 24 hours. Cell culture medium apoB was quantified by immunoblot. VLDL fractions were isolated by ultracentrifugation, and cholesterol and triglyceride concentrations in VLDL fractions were assayed. (E) McA-RH7777 cells were treated with siRNA against tPA mRNA (si-tPA) or scrambled RNA for 24 hours. VLDL was isolated from the medium by ultracentrifugation, and cholesterol and triglyceride concentrations in VLDL were assayed. Cell culture medium apoB was assayed by immunoblot. Data are shown as means ± SEMs; *P < 0.05 by two-tailed Student’s t test.