High glucose decreases the expression of ATP-binding cassette transporter G1 in human vascular smooth muscle cells*

ObjectiveATP-binding cassette transporters(ABC) Al and Gl play an important role in mediating cholesterol efflux and preventing macrophage foam cell formation. In this study, we examined the regulation of ABC transporters by high glucose in human vascular smooth muscle cells(VSMCs), the other precursor of foam cells.MethodsIncubation of human VSMCs with D-glucose(5 to 30 mM) for 1 to 7 days in the presence or absence of antioxidant and nuclear factor(NF)- κ B inhibitors, the expressions of ABCA1 and ABCG1 were analyzed by real time PCR and Western blotting.ResultsHigh glucose decreased ABCG1 mRNA and protein expression in cultured VSMCs, whereas the expression of ABCA1 was not significantly decreased. Down-regulation of ABCG1 mRNA expression by high glucose was abolished by antioxidant N-acetyl-L-cysteine(NAC) and NF- κ B inhibitors, BAY 11-7085 and tosyl-phenylalanine chloromethyl-ketone(TPCK).ConclusionHigh glucose suppresses the expression of ABCG1 in VSMCs, which is the possible mechanism of VSMC derived foam cell transformation.