FIGURE 4.

Lipoproteins in zebrafish homogenates activate murine macrophages. A, lipoprotein and lipoprotein-deficient fractions isolated from zebrafish larva homogenates by ultracentrifugation were analyzed in native agarose gel electrophoresis with Fat Red staining. A human plasma sample was used as a positive control. B, RAW macrophages were incubated for 20 min with lipoprotein and lipoprotein-deficient fractions isolated from control and HCD-fed zebrafish larvae, and cell lysates were analyzed by immunoblot. RAW cells activated with mmLDL were used as a positive control. C–F, J774 macrophages were incubated for 20 min with 1 μg/μl (protein) of homogenates of control or HCD-fed zebrafish larvae (C and D) or with lipoproteins isolated from zebrafish homogenates by ultracentrifugation (E and F). At the end of incubation, cells were fixed and stained to visualize F-actin cytoskeleton (red) and nuclei (blue). Scale bar, 10 μm. G, cell surface area were measured in cells incubated with lipoprotein fractions isolated from control and HCD-fed zebrafish homogenates. Shown are the mean ± S.E. (n = 50); *, p < 0.001. p-, phospho-.