Effect of ferulic acid on cholesterol efflux in macrophage foam cell formation and potential mechanism / 中国中药杂志

The formation of macrophage-derived foam cells is a typical feature of atherosclerosis (AS). Reverse cholesterol efflux (RCT) is one of important factors for the formation of macrophage foam cells. In this study, macrophage form cells were induced by oxidized low density lipoprotein (ox-LDL) and then treated with different concentrations of ferulic acid, so as to observe the effect of ferulic acid on the intracellular lipid metabolism in the ox-LDL-induced macrophage foam cell formation, the cholesterol efflux and the mRNA expression and protein levels of ATP binding cassette transporter A1 (ABCA1) and ATP binding cassette transporter G1 (ABCG1) that mediate cholesterol efflux, and discuss the potential mechanism of ferulic acid in resisting AS. According to the findings, compared with the control group, the ox-LDL-treated group showed significant increase in intracellular lipid content, especially for the cholesterol content; whereas the intracellular lipid accumulation markedly decreased, after the treatment with ferulic acid. The data also demonstrated that the mRNA and protein expressions of ABCA1 and ABCG1 significantly increased after macrophage foam cells were treated with different concentrations of ferulic acid. In summary, ferulic acid may show the anti-atherosclerosis effect by increasing the surface ABCA1 and ABCG1 expressions of macrophage form cells and promoting cholesterol efflux.

Mitofusin2 decreases intracellular cholesterol of oxidized LDL-induced foam cells from rat vascular smooth muscle cells / 华中科技大学学报（医学）（英德文版）

Mitofusin2 (Mfn2) plays a pivotal role in the proliferation and apoptosis of vascular smooth muscle cells (VSMCs). The purpose of this study was to investigate the effects of Mfn2 on the trafficking of intracellular cholesterol in the foam cells derived from rat VSMCs (rVSMCs) and also to investigate the effects of Mfn2 on the expression of adenosine triphosphate-binding cassette subfamily A member 1 (ABCA1), adenosine triphosphate-binding cassette subfamily G member 1 (ABCG1) and peroxisome proliferator-activated receptor gamma (PPARγ). The rVSMCs were co-cultured with oxidized low density lipoprotein (LDL, 80 μg/mL) to produce foam cells and cholesterol accumulation in cells. Before oxidized LDL treatment, different titers (20, 40 and 60 pfu/cell) of recombinant adenovirus containing Mfn2 gene (Adv-Mfn2) were added into the culture medium for 24 h to transfect the Mfn2 gene into the rVSMCs. Then the cells were harvested for analyses. The protein expression of Mfn2 was significantly higher in Adv-Mfn2-transfected group than in untransfected group (P<0.05), and the expression levels significantly increased when the titer of Adv-Mfn2 increased (P<0.05). At 24 or 48 h after oxidized LDL treatment, rVSMCs became irregular and their nuclei became larger, and their plasma abounded with red lipid droplets. However, the number of red lipid droplets was significantly decreased in Adv-Mfn2-transfected group as compared with untransfected group. At 48 h after oxidized LDL treatment, the intracellular cholesterol in rVSMCs was significantly increased (P<0.05), but it was significantly decreased in Adv-Mfn2-transfected group as compared with untransfected group (P<0.05), and it also significantly decreased when the titer of Adv-Mfn2 increased (P<0.05). The mRNA and protein expression levels of ABCA1 and ABCG1 were significantly increased in Adv-Mfn2-transfected group as compared with untransfected group (P<0.05). Though the mRNA and protein expression levels of PPARγ was not significantly increased (P>0.05), the phosporylation levels of PPARγ were significantly decreased in Adv-Mfn2-transfected group as compared with untransfected group (P<0.05). These results suggest that the transfection of Adv-Mfn2 can significantly reduce intracellular cholesterol in oxidized LDL-induced rVSMCs possibly by decreasing PPARγ phosporylation and then increasing protein expression levels of ABCA1 and ABCG1, which may be helpful to suppress the formation of foam cells.

Endothelial dysfunction induced by high glucose is associated with decreased ATP-binding cassette transporter G1 expression / 南方医科大学学报

<p><b>OBJECTIVE</b>To investigate the role of ATP-binding cassette transporter G1 (ABCG1) in endothelial dysfunction induced by high glucose.</p><p><b>METHODS</b>Human aortic endothelial cells (HAECs) were incubated in the presence of 5.6 or 30 mmol/L glucose for 24-72 h with or without a 2-h pretreatment with the LXR agonist 22(R)-hydroxycholesterol. Real-time PCR and Western blotting were used to measure the mRNA and protein expressions of ABCG1; the intracellular cholesterol efflux and endothelial nitric oxide synthase (eNOS) activity were measured by scintillation counting.</p><p><b>RESULTS</b>High glucose time-dependently suppressed ABCG1 expression and cholesterol efflux to HDL in HAECs. High glucose also decreased eNOS activity. ABCG1 down-regulation induced by high glucose, along with decreased cholesterol efflux and eNOS activity, was abolished by treatment of the cells with the LXR agonist.</p><p><b>CONCLUSION</b>Endothelial dysfunction induced by high glucose is associated with decreased ABCG1 expression.</p>

Association of the ABCG1 gene polymorphism with the susceptibility and severity of coronary atherosclerotic disease / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To investigate the association of the ATP-binding cassette sub-family G member 1 (ABCG1) gene polymorphisms with coronary atherosclerotic disease (CAD) in Chinese Han population.</p><p><b>METHODS</b>A population based case-control association study was carried out in 541 patients with CAD and 649 healthy controls from Chinese Han population. Two single nucleotide polymorphisms (SNPs) of the ABCG1 gene were genotyped using polymerase chain reaction-restriction fragment length polymorphism. Logistic regression was used to compare the genotypic and allelic frequency difference.</p><p><b>RESULTS</b>The frequency of allele C of rs225374 was significantly higher in the CAD patients than that in the healthy controls (OR=1.186, 95%CI: 1.009-1.394, P=0.039), while the difference was also significant in the male subgroup (OR=1.236, 95%CI: 1.014-1.506, P=0.036). A statistically higher frequency of rs1044317 allele A was found in the CAD patients in comparison to the healthy controls (OR=1.187, 95%CI: 1.009-1.397, P=0.039). In case-only association study, rs225374 showed significant association in the high Gensini score group compared with the low Gensini score group (OR=1.303, 95%CI: 1.024-1.657, P=0.031).</p><p><b>CONCLUSION</b>The two SNPs of the ABCG1 gene might be associated with the susceptibility and severity of CAD in Chinese Han population.</p>

High glucose suppresses ABCG1 expression by increasing oxidative stress and inducing nuclear factor-kappaB activation in vascular smooth muscle cells / 南方医科大学学报

<p><b>OBJECTIVE</b>To investigate the role of high glucose in the expression of ATP-binding cassette (ABC) transporters A1 (ABCA1) and G1 (ABCG1) in human vascular smooth muscle cells (VSMCs) and its possible mechanisms.</p><p><b>METHODS</b>VSMCs were incubated in the presence of glucose at the concentrations ranging from 5 to 30 mmol/L for 1 to 7 days, and real-time PCR and Western blotting were used to measure the mRNA and protein expressions of ABCA1 and ABCG1. The effects of cells pretreatment with antioxidant NAC (10 mmol/L) and nuclear factor-kappaB (NF-kappaB) inhibitors BAY 11-7085 (10 micromol/L) and TPCK (10 micromol/L) were also tested on ABCA1 and ABCG1 expressions.</p><p><b>RESULTS</b>High glucose suppressed, in a time- and dose-dependent manner, ABCG1 expression in incubated human VSMCs, and this effect was abolished by pretreatment with the antioxidant and nuclear factor-kappaB (NF-kappaB) inhibitors, but ABCA1 expression was not significantly decreased in the presence of high glucose.</p><p><b>CONCLUSION</b>High glucose suppresses ABCG1 expression in human VSMCs possibly due to increased oxidative stress and NF-kappaB activation induced by high glucose.</p>