Fig. 5. Akt1^−/− macrophages display similar binding to lipoproteins and foam cell formation and shown increased susceptibility to apoptosis by cholesterol overload.

Specific binding (a) and uptake (b) of DiI-labeled acLDL in peritoneal macrophages isolated from ApoE^−/− and ApoE^−/− Akt1^−/− mice. The data are mean ± S.E. of triplicate samples repeated in two separate experiments. (c) Foam cells from ApoE^−/− and ApoE^−/− Akt1^−/− mice treated with oxLDL for 24h and quantitative analysis of three independent experiments. Bars, 50µm. (d) Apoptotic cells determined by their hypochromic, subdiploid staining profiles (SubG1 population) after incubation ApoE^−/− and ApoE^−/− Akt1^−/− peritoneal macrophage with (oxLDL100 µg/ml) for 24h. The data are mean ± S.E.M. of triplicate samples repeated from three different groups of mice.*, p < 0.05 compared with ApoE^−/−. (e) Quantitative determination of apoptotic macrophages stained positive for annexin V. Thioglicollate-elicited peritoneal macrophage from either ApoE^−/− and ApoE^−/− Akt1^−/− mice were incubated with or without acLDL (100 µg/ml) and 58035, (10 µg/ml) an ACAT inhibitor or oxLDL (100 µg/ml) for 36h. All results represent mean ± S.E.M. of triplicate samples from three different sets of mice. Bars, 100µm. (f) Apoptotic cells and macrophages in lesions from ApoE^−/− and ApoE^−/− Akt1^−/− mice after 12 weeks of high cholesterol diet were detected by TUNEL and CD68 staining respectively. The data are expressed as the number of TUNEL positive cells per mm² cellular lesion area. Bars, 100µm. (g,h) Transplantation of bone marrow cells from ApoE ^−/− or ApoE^−/− Akt1 ^−/− mice into ApoE^−/−Akt1^−/− or ApoE^−/−mice, respectively, followed by lesion analysis in aorta (g) and cross sections of aortic sinus (h). Data are mean± S.E.M., from 5 mice (males) in each group*, p < 0.05.