Figure 5. α_Mβ₂ reduces expression of lipid uptake proteins in gender-dependent manner and enhances expression of lipid efflux proteins.

(A) FACS analysis of peritoneal macrophages harvested from α_M^−/−/ApoE^−/− and ApoE^−/− mice fed CD or HFD for 16 weeks. The cells were double-stained with Alexa 488-labeled Abs to the lipid regulating proteins as indicated and with PE-labeled macrophage F4/80 Ab. The data show expression of each lipid regulator in the F4/80-positive population, which was > 80 % of total cell numbers. (left panel: *P<0.01 female α_M^−/−/ApoE^−/− vs female ApoE^−/− mice and right panel:*P<0.05 α_M^−/−/ApoE^−/− vs ApoE^−/− mice, n=8). The results are representative of three independent experiments. (B) Western blot analysis of macrophage lysates from (A) probed with antibodies to the indicated lipid regulators and to β-actin as loading controls. Equal volumes of each macrophage lysate from 4 mice of each group were combined, protein assays were performed by Bradford method and equal protein amounts were loaded onto the gel. Images are representative of four independent experiments. (C) Densitometric analysis of Western blots from B. (CD36, SR-A1:*P<0.05 female α_M^−/−/ApoE^−/− vs female ApoE^−/− mice; SR-B1, ABCG1: *P<0.01; ABCA1:*P<0.05; PPARγ:*P<0.001 α_M^−/−/ApoE^−/− vs ApoE^−/− mice, n=6) (D) Quantitative RT-PCR of transcripts of various lipid regulators in peritoneal macrophages isolated from α_M^−/−/ApoE^−/− and ApoE^−/− mice fed HFD for 16 weeks. Expression levels are plotted as fold change relative to the levels in ApoE^−/− macrophages (assigned value=1) isolated from gender matched controls. GAPDH was used as internal control for normalization. (left panel: *P<0.001α_M^−/−/ApoE^−/− vs ApoE^−/− mice; middle panel:*P<0.001 female α_M^−/−/ApoE^−/− vs female ApoE^−/− mice; right panel:*P<0.001 α_M^−/−/ApoE^−/− vs ApoE^−/− mice, n=6).