Fig. 6.

Abcg1 but not Abca1 is preferentially expressed by M2 macrophages. BMDMs and M1 and M2 macrophages were cultured from WT (C57BL/6 male) bone marrow cells as described in Materials and Methods. mRNA and protein levels were evaluated for Abcg1 (A–C) and Abca1 (D–F) for cells without cholesterol loading. Additional cells were incubated with ac-LDL for 24 h and then quantified for Abcg1 (A, black bars) and Abca1 (D, black bars) expression. mRNA levels were quantified by RT-PCR and normalized to L32 levels. Protein was isolated from cell lysates and prepared for SDS-PAGE and immunoblotting using GAPDH as a protein loading control as in Materials and Methods. Signal bands were quantified by densitometry using National Institutes of Health ImageJ software for protein levels. Values are presented as mean ± SEM (n = 3–4). * P < 0.05, ** P < 0.01, *** P < 0.001 between BMDM and M1 or M2 groups within noncholesterol and cholesterol-loaded groups (n = 3); † P < 0.05, †† P < 0.01, ††† P < 0.001 between noncholesterol and cholesterol-loaded cells within BMDM, M1, and M2 cell types (n = 4).