Berberine promotes the development of atherosclerosis and foam cell formation by inducing scavenger receptor A expression in macrophage

Berberine is identified to lower the serum cholesterol level in human and hamster through the induction of low density lipoproteins （LDL） receptor in hepatic cells. To evaluate its potential in preventing atherosclerosis, the effect of berberine on atherosclerosis development in apolipoprotcin E-deficient （apoE^-/-） mice was investigated. In apoE^-/- mice, berberine induced in rivo foam cell formation and promoted atheroselerosis development. The foam cell formation induced by berberinc was also observed in mouse RAW264.7 cells, as well as in mouse and human primary macrophages. By inducing scavenger receptor A （SR-A） expression in macrophages, berberine increased the uptake of modified LDL （DiO-Ac-LDL）. Bcrberine-induced SR-A expression was also observed in macrophage foam cells in vivo and in the cells at atherosclerotic lesion. Analysis in RAW264.7 cells indicated that berberine induced SR-A expression by suppressing PTEN expression, which led to sustained Akt activation. Our results suggest that to evaluate the potential of a cholesterol-reducing compound in alleviating atherosclerosis, its effect on the ceils involved in atherosclerosis development, such as macrophages, should also be considered. Promotion of foam cell formation could counter-balance the beneficial effect of lowering serum cholesterol.

MicroRNA sequences modulating inflammation and lipid accumulation in macrophage “foam” cells: Implications for atherosclerosis

Accumulation of macrophage"foam"cells,laden with cholesterol and cholesteryl ester,within the intima of large arteries,is a hallmark of early"fatty streak"lesions which can progress to complex,multicellular atheromatous plaques,involving lipoproteins from the bloodstream and cells of the innate and adaptive immune response.Sterol accumulation triggers induction of genes encoding proteins mediating the atheroprotective cholesterol efflux pathway.Within the arterial intima,however,this mechanism is overwhelmed,leading to distinct changes in macrophage phenotype and inflammatory status.Over the last decade marked gains have been made in understanding of the epigenetic landscape which influence macrophage function,and in particular the importance of small non-coding micro-RNA(miRNA)sequences in this context.This review identifies some of the miRNA sequences which play a key role in regulating"foam"cell formation and atherogenesis,highlighting sequences involved in cholesterol accumulation,those influencing inflammation in sterol-loaded cells,and novel sequences and pathways which may offer new strategies to influence macrophage function within atherosclerotic lesions.

Effects of Andrographolide on the Activation of Mitogen Activated Protein Kinases and Nuclear Factor-κ B in Mouse Peritoneal Macrophage-derived Foam Cells

Objective： To observe the effect of andrographolide on the activation of mitogen-activated protein kinases （MAPKs） and expression of nuclear factor- kB （NF-kB） in macrophage foam cells. Methods： The mouse peritoneal macrophages were cultured in the media in the presence of oxidized low-density lipoprotein （ox-LDL）, ox-LDL＋andrographolide, or neither （control）. The phosphorylation of MAPK molecules （p38MAPK, JNK, ERK1/2） and the expressions of NK- kB p65 were examined by Western blot. Results： As compared with cells in the control group, the expressions of phospho-p38 and NF- kB p65 were increased in the cells cultured with either ox-LDL or ox-LDL＋andrographolide （P〈0.01）, but attenuated significantly in the presence of ox-LDL＋ andrographolide when compared with ox-LDL （P〈0.05）. The phospho-JNK increased in the presence of either ox-LDL or ox-LDL＋andrographolide when compared with control cells （P〈0.01）, but no significant difference existed between ox-LDL and ox-LDL＋andrographolide （P〉0.05）. The expression of phospho-ERK1/2 was increased in the presence of ox-LDL compared with the control cells （P〈0.01）, but no significant differences existed between the cells cultured in the presence of ox-LDL＋andrographolide and the control medium （P〉0.05）. Conclusions： Andrographolide could inhibit the activation of ERK1/2, p38MAPK and NK-kB induced by ox-LDL in macrophage foam cells, which might be one of its mechanisms in preventing atherosclerosis.