Effect Of Ox-LDL And Nuciferine On The Function And Expression Of ABCA1 In THP-1 Macrophages-derived Foam Cells

Objective:In order to study the effect of ox-LDL and nuciferine on the expression of ATP binding cassette transporter A1 (ABCA1) in THP-1 macrophage-derived foam cells,and makes further effort to explore the role of ox-LDL in initiation and progression of atherosclerosis,and whether nuciferine can be or get in the way of progression of atherosclerosis.Methods:1. Macrophages were derived from human monocyte lines THP-1 by PMA.THP-1 derived macrophages were coincubated with ox-LDL at various concentration (25mg/L,50mg/L,100mg/L) respectively for 24 hours into foam cells. THP-1 macrophages incubated without ox-LDL were the control groups. The course of the differentiation stimulated by ox-LDL from macrophages to foam cells was observed at microscope.Oil Red O staining was used to observe the intracellular lipid droplets. ABCA1 mRNA and protein level were detemrined by Sybr Green reverse transcription-polymerase chain reaction and western blot,respectively.2. Macrophages were derived from human monocyte lines THP-1 by PMA. THP-1 derived macrophages were incubated with ox-LDL (50mg/L) for 24 hours into foam cells.Then the foam cells were coincubated with nuciferine at various concentration (25mg/L,50mg/L,100mg/L) respectively for 24 hours .THP-1 macrophages incubated without ox-LDL or nuciferine were the control groups. Oil Red O staining was used to observe the intracellular lipid droplets. ABCA1 mRNA level were quantified by Sybr Green reverse transcription-polymerase chain reaction, protein level by western blot,respectively.Results:1. The changes of cellular characteristics in the course of the differentiation that from monocyte lines THP-1 to macrophages induced by PMA were observed at microscope: from suspension to pasting wall : from suspension to adherent;from round shape to shuttle,irregular shape. The changes of cellular characteristics in the differentiation from macrophages into foam cells were showed by Oil red O staining: there were many lipid droplets. The result showed that lipid droplets in ox-LDL groups were more than the control groups ,and nuciferine increased the lipid droplets in cells when compared with the control group.2. The mRNA levels of ABCA1 expression:①There was markedly higher ABCA1 mRNA expression in ox-LDL groups when compared with the control group.(P<0.05),in ox-LDL groups,ABCA1 mRNA expression level was the highest at 50mg/L ox-LDL group.(P<0.05)②THP-1 derived macrophages were incubated with ox-LDL (50mg/L) for into foam cells which the expression level of ABCA1mRNA was minimal. Nuciferine enhanced the expression of ABCA1mRNA significantly(P<0.05),but the degree of degression was not correlated positively to the concentration of nuciferine.3. The expression levels of ABCA1 protein:①There was markedly higher ABCA1 protein expression in ox-LDL groups when compared with the control group.(P<0.05),in ox-LDL groups,The expression level of ABCA1 protein was the highest at 50mg/L ox-LDL group(P<0.1).②THP-1 derived macrophages were incubated with ox-LDL (50mg/L) for into foam cells which the expression level of ABCA1 protein was minimal .Nuciferine enhanced the expression of ABCA1 protein significantly (P<0.05),but the degree of degression was not correlated positively to the concentration of nuciferine.Conclusion:1. Ox-LDL enhances the expression of ABCA1 in THP-1 derived macrophages .Ox-LDL brings about the cholesterol accumulation , finally leading to the foam formation of THP-1 derived macrophage.2. Nuciferine enhance the expression of ABCA1 in THP-l macrophages -derived foam cells . Nuciferine decreasing the cholesterol accumulation to lessen the foam formation of THP-l macrophages -derived foam cells.3. To suppose that nuciferine decrease the cholesterol accumulation and increase the cholesterol influx by promoting the expression of ABCA1.