ABSTRACT
Aim To investigate the effects of scutellarein on the macrophage foam cell formation and cholesterol efflux, and the underlying mechanism. Methods THP-1 cells were differentiated with PMA, and the cell viability was detected by MTT assays. The effects of scutellarein on the cholesterol efflux and macrophage foam cell formation were evaluated by using NBD-la-beled cholesterol and the cholesterol detection kit. The effects of scutellarein on the activation of PPARγ-LXRα-ABCA1 signaling pathway were determined by molecular docking, ELISA, dual-luciferase reporter and Western blot. The effects of PPARγ knowdown on scutellarein-induced cholesterol efflux and inhibiting macrophage foaming were analyzed by siRNA interference. Results Scutellarein dose-dependently inhibited oxLDL-induced cholesterol accumulation, accelerated cholesterol efflux and significantly increased the protein expression of LXRα and ABCA1. At the same time, scutellarein could bind PPARγ and initiate its downstream LXRa-ABCAl signaling pathway. In addition, gene silencing of PPARγ not only significantly inhibited scutellarein-induced LXRα-ABCA1 signaling pathway and cholesterol efflux, but also reversed the inhibitory effect of scutellarein on macrophage foaming. Conclusions Scutellarein could promote the cholesterol efflux by activating PPARγ and initiating the downstream LXR-ABCA1 signaling pathway, thereby prevent the macrophage foam cell formation.
ABSTRACT
Objective To investigate the effect of miR-152 on ox-LDL induced cholesterol accumulation in RAW264.7 macrophages and to verify its target genes. Methods RAW264.7 macrophages were divided into two groups:miR-152 group and negative control group. Total cholesterol(TC),cholesterol ester(CE)concentra- tion and the ratio of CE/TC were observed in the two group by ox-LDL for 48 h. Furthermore,bioinformatics meth-od,dual luciferase reporter assay,real-time quantitative PCR and Western blot were applied to detect the target gene of miR-152. Results As compared with the control group,the contents of TC,CE and the ratio of CE/TC were increased in the miR-152 group. The mRNA and protein expressions of ABCA1 were significantly lower in miR-152 group. Conclusions MiR-152 could inhibit macrophage foam cell formation through decreasing the expres-sion of ABCA1.
ABSTRACT
Objective To investigate the effect of miR-152 on ox-LDL induced cholesterol accumulation in RAW264.7 macrophages and to verify its target genes. Methods RAW264.7 macrophages were divided into two groups:miR-152 group and negative control group. Total cholesterol(TC),cholesterol ester(CE)concentra- tion and the ratio of CE/TC were observed in the two group by ox-LDL for 48 h. Furthermore,bioinformatics meth-od,dual luciferase reporter assay,real-time quantitative PCR and Western blot were applied to detect the target gene of miR-152. Results As compared with the control group,the contents of TC,CE and the ratio of CE/TC were increased in the miR-152 group. The mRNA and protein expressions of ABCA1 were significantly lower in miR-152 group. Conclusions MiR-152 could inhibit macrophage foam cell formation through decreasing the expres-sion of ABCA1.
ABSTRACT
Objective To investigate whether and how regulatory T cells(Tr) affect macrophages foam-cell formation, and thereby investigate the mechanism of Tr in the development of atherosclerosis. Methods Tr were isolated from lymphocyte suspensions by magnetic cell sorting-column and analyzed by flow cytometry. Macrophages were cultured alone, with CD4~+ CD25~+ T, or CD4~+ CD25~- T cells in the pres-ence of oxLDL for 48 h to transform macrophages into foam cells. Oil red O staining and cellular lipid meas-urement were used to identify macrophage foam cell formation. Semi-quantitative PCR, quantitative real-time PCR and Western blot analysis were carried out to explore the mechanism of Tr-mediated suppression on macrophages foam cell formation. Results Foam cell formation, as identified by oil red O staining, was readily apparent in cells treated with CD4~+ CD25~- T cells and without T cells. After treatment with Tr, a marked decrease(13.9% ± 5.6% ) in foam cell count was observed, compared with untreated cells(13.9% ±5.6% vs 52.9% ± 10.4%, P<0.001 ) or CD4~+ CD25~- T-treated cells(13.9% ± 5.6% vs 53. 1% ± 17.2%, P<0.001 ), 52.9% ± 10.4% and 53.1% ± 17.2%, respectively (P<0.001). The similar effect of Tr was obtained when extracted oil red O and measured by a spectrophotometer. Cholesteryl ester ac-cumulation also used to quantify foam cell formation. Compared with untreated (no T) and CD4~+ CD25~- Tr-treated macrophage cells (CD25~-), the lipids accumulation in CD4~+ CD25~+ Tr-treated macrophage foam cells(CD25~+) was significantly reduced. Total cellular cholesterol and cellular cholesteryl ester was siginifi-cantly reduced in CD25~+ cultures relative to no T[TC(total cholesterol): 57.46 ± 17.92 vs 159.48 ± 16.38, P<0.01 ; CE(esterified cholesterol): 26.68 ± 8.88 vs 102.54 ± 16.67, P<0.001] or CD25~- (TC: 58.50±7.00 vs 150.55±25.11, P<0.01; CE: 26.68±8.88 vs96.90 ± 11.95, P<0.001) cul-tures. Moreover, PCR and Western blot analysis showed that the expression of both CD36 and SRA in Tr-treated macrophage foam cells was significantly down-regulated. Conclusion Results collectively suggest that CD4~+ CD25~+ Tr cells may inhibit macrophage foam-cell formation, which is largely attributed to a down-regulated expression in scavenger receptor in Tr-treated macrophage foam cells.