Effect of apolipoprotein A-I mimetic peptides on cholesterol efflux in RAW264.7 cells / 中南大学学报(医学版)

ABSTRACT

OBJECTIVE@#To determine the effect and possible mechanism of an apolipoprotein (apo) A-I mimetic peptide, D-4F, on cholesterol efflux in RAW264.7 macrophages.@*METHODS@#RAW264.7 macrophages were incubated in the medium containing 8-bromo cAMP (8-Br-cAMP, 0.5 mmol/L) and ox-LDL (50 μg/mL) for 24 h. Then various concentrations of D-4F (0-100 μg/mL) or H89 (20 μmol/L, a protein kinase A inhibitor) were added for the purpose of interference. The intracellular cyclic AMP (cAMP) level was determined by enzyme-linked immunoabsobant assay (ELISA). ATP binding cassette transporter A1 (ABCA1) expression in the macrophages was quantitated by real-time PCR and Western blot.@*RESULTS@#D-4F significantly increased the cholesterol efflux in both concentration and time-dependent manner accompanied by the increase in the intracellular cAMP level, ABCA1 mRNA and protein expression. The effect of D-4F on cholesterol efflux ABCA1 expression was enhanced by 8-Br-cAMP. Although H89 did not affect the basal cholesterol efflux and ABCA1 expression, it could attenuate the effect of 8-Br cAMP.@*CONCLUSION@#D-4F affects cholesterol efflux, cAMP level, and ABCA1 expression in macrophages, which is likely involved in the pathway of cAMP/PKA/ABCA1.