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Updated: Oct 4, 2026

Cholesterol Efflux Assay
Published on: March 6, 2012
Biliary anionic peptide fraction/calcium binding protein inhibits apolipoprotein A-I-mediated cholesterol efflux from
M J van Wijland1, D R de Waart, A K Groen
1Laboratory of Experimental Hepatology, Academic Medical Center, Meibergdreef 9, 1105 AZ Amsterdam, The Netherlands. m.vanwijland@amc.uva.nl
Abstract:
The ABC transporter ABCA1 has been implicated to control cholesterol efflux in a variety of cell types including macrophages, fibroblasts, and intestinal epithelial cells. In this study we have investigated whether the 6-kD protein anionic peptide fraction/calcium binding protein (APF/CBP) which has homology to apolipoprotein AI may regulate efflux mediated by lipoproteins. APF/CBP was purified from T-tube bile by ultracentrifugation and preparative reversed phase HPLC. Cholesterol efflux to a variety of acceptors was determined using cultured fibroblasts from controls and patients with Tangiers disease. APF/CBP (0.1 to 2.4 microg/ml) inhibited ApoA-1 (2 microg/ml) mediated cholesterol efflux from normal fibroblasts in a dose dependent manner but had no effect on aspecific efflux to methyl-beta-cyclodextrin or phosphatidylcholine liposomes. In ABCA1 deficient fibroblasts no effect of APF/CBP on efflux was seen. We conclude that APF/CBP specifically interferes with ApoA-I mediated cholesterol trafficking. We hypothesize that competitive binding to ABCA1 may explain the decreased ApoA-I mediated efflux from fibroblasts.
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