Effects Of ADMA On Cholesterol Ester Content And The Expression Of ACAT-1 In Cell Differentiation From Mononuclear/macrophage Cells To Foam Cells

Objective :To explore the influence and mechanism of Asymmetric dimethylarginine(ADMA) in cell differentiation from mononuclear/macrophage cells to foam cells by investigating the effects of ADMA on cholesterol ester content and the expression of acyl-coenzyme A:acylcholesterol transferase-1(ACAT-1) .Method:1. Cultured THP-1 monocyte cell was induced into macrophages by 160nmol/L phorbol myristate acetate(PMA) for 48h and then incubated with 80mg/L oxidized low density lipoprotein(ox-LDL) for 24h, macrophages were induced into foam cells. Transmission light microscope(using red oil O staining technique)was applied to investigate the morphology and change of foam cells.2. After ADMA of different concentrations (1μmol/L,5μmol/L, 10μmol/L, 20μmol/L, 30μmol/L) were incubated with THP-1 macrophage-derived foam cells for 24h and 20μmol/L ADMA was incubated with THP-1 macrophage-derived foam cells for 0h,6h,12h,24h,48h, the cholesterol ester content of foam cells was measured by enzyme assay.3. After 20μmol/L ADMA was incubated with THP-1 monocyte cells, macrophage cells and foam cells for 24h. The expression of ACAT-1 in protein and mRNA were measured by means of Western blot and RT-PCR respectively.Results:1. The mononuclear cells line THP-l could be differentiated into macrophages after 48 hours induction by the PMA and into foam cells after 24 hours induction by ox-LDL.2. Compared with the control group, treatment of THP-1 macrophage-derived foam cells with 20μmol/L ADMA for12h,24h,48h, resulted in an increase in the cholesterol ester content of foam cells (p<0.01). 3. Compared with the control group, treatment of THP-1 macrophage-derived foam cells with 5μmol/L,10μmol/L,20μmol/L,30μmol/L ADMA for 24h resulted in an increase in the cholesterol ester content of foam cells(p<0.01).4. Compared with the monocyte cells, expression of ACAT-1 in protein and mRNA in macrophage cells (p<0.05) and foam cells obviously increased (p<0.01). Compared with the macrophage cells, expression of ACAT-1 in protein and mRNA in foam cells increased without significant difference (p>0.05).5. Compared with the control group respectively treatment of monocyte cells, macrophage cells and foam cells with ADMA result in an increase in the protein and mRNA levels for ACAT-1(p<0.01).Conclusion:1. ADMA could increase the cholesterol ester content of foam cells.2. ACAT-1 gene expression upregulated during the differentiation of monocytes/ macrophages into foam cells and ADMA could furthermore increase the expression of ACAT-1.3. ADMA might increase the cholesterol ester content of foam cells via upregulating the expression of ACAT-1, which might result in the atherosclerosis.