Fig. 3.

Lp(a) stimulates ABCA1 promoter activity and cholesterol efflux. A: ABCA1 promoter activity. HepG2 cells were transiently transfected with an ABCA1 promoter construct and promoter activity assessed by luciferase reporter assay after treatment with 1, 5, and 10 μg/ml Lp(a) protein. Luciferase fluorescence was normalized against the fluorescence from a Renilla transfection control and expressed relative to control untreated cells. B: Cholesterol efflux assays. HepG2 cells were loaded with [³H]cholesterol for 48 h prior to treatment with 1, 5, and 10 μg/ml Lp(a) protein. Cells were incubated with apoA1 acceptor for 2 h and apoA1-mediated cholesterol efflux calculated. Results are expressed as mean ± SE for at least two experiments performed in triplicate. *P < 0.05, **P < 0.01, ***P < 0.001 compared with control.