Figure 2

CRP sustains oxLDL-stimulated expression of ABCA1, PPARγ, CD36 and PPRE leading to cholesterol efflux. (A and B). 293FT cells transfected with pELAM-Luc-NFκB-Luc pRL-TK (A) or pELAM-Luc-PPRE-Luc pRL-TK (B) were treated with hCRP (up to 5 μg/ml/24h), LPC or oxLA (10 μg/ml/24h). FcγRs were blocked with monoclonal neutralizing antibodies against FcγRI (clone:10.1) and FcγRII (clone:7.3) (‘Anti-FcγR’, 15 μg/ml each). Data represent mean values ± SD of luciferase activity of the cell lysates after adjusting relative to the β-gal activity and the protein content. *; p < 0.05 vs the control (#), S; not statistically significant vs. the control (#), NS; not statistically significant each other. (C). Human macrophages were treated with 10 μg/ml/24h hCRP, fully oxidized LDL (oxLDL), or a mixture of hCRP-oxLDL, and the protein expression levels of ABCA1, PPARγ, and CD36 were estimated by an immunoblot assay. The immunoblotting image represents one of three independent experiments. Data are given as mean ± SD from three independent experiments. *; p < 0.05 vs. untreated, NS; not statistically significant. (D). Human macrophages were incubated with 2 mCi/mL [³H]cholesterol for 24 h, and 10 μg/ml oxLDL or hCRP was added and maintained further for 24 h. Unbound [³H]cholesterol was washed off and cells were further incubated for 4 h. The percentage of cell-associated [³H]-cholesterol released into the media in 4 h was obtained by performing a cholesterol efflux assay as described in the Methods. Data are given as mean ± SD from three independent experiments. NS; not statistically significant. CRP does not inhibit oxLDL-stimulated cholesterol efflux by human macrophages.