Figure 3.

Cardiomyocytes are also capable of Hep^L uptake. Cell lysates of primary rat cardiomyocytes, RAOEC or RHMEC were obtained for determination of heparanase mRNA (A) and protein (B), n = 4–8. Cardiomyocytes seeded on coverslips were placed in a 6-well plate, and treated with 500 ng/mL myc-Hep^L prior to immunofluorescence staining examined under a confocal microscope. The merged image of heparanase and lysosomes is described in the third (scale bar, 10 µm) and fourth (scale bar, 5 µm) panels from left (C) and are data from a representative experiment. Isolated myocytes were also treated with or without myc-Hep^L for 4 h. Following this incubation, nuclear and cytosolic fractions were isolated, and Hep^A protein levels determined by western blot (D). Cell lysates of primary rat cardiomyocytes, RAOEC, or RHMEC were obtained for determination of LRP1 mRNA (E) and protein (F), n = 4 and n = 8. In a different experiment, in cardiomyocytes incubated with HG, cells were pre-treated with or without 400 nM RAP or 40 μg/mL LRP1 neutralizing antibody for 1 h prior to incubation with 500 ng/mL myc-Hep^L for 4 h. Cell lysates were collected to determine Hep^L uptake, n = 4 (G). 40 μg/mL IgG was used as a control for the LRP1 neutralizing antibody experiment. *P < 0.05, **P < 0.01.