Effect of IL-34 on cholesterol level in macrophages differentiating to foam cells

doi:10.3969/j.issn.1009-0126.2017.01.005

Abstract：Objective To study the effect of IL-34 on cholesterol level in macrophages differentiating to foam cells and its molecular mechanism.Methods RAW246.7 macrophages were divided into control group,oxLDL group (40 μg/ml),oxLDL+20 ng/ml IL-34 group and oxLDL+50 ng/ml IL-34 group.Formation of foam cells was detected with Oil Red O staining after 24 h culture.Serum levels of TC,cholesterol ester and free cholesterol in macrophages were measured by colorimetry.Expressions of ACAT-1,nCEH mRNA and protein in macrophages were detected by RT-PCR and Western blot respectively.Results No significant difference was found in serum levels of TC and cholesterol ester in macrophages between oxLDL group and 20 ng/ml oxLDL group (P＞0.05).The number of Oil Red O stained lipid droplets in macrophages was significantly greater and the serumlevels of TC,and cholesterol ester were significantly higher in oxLDL+50ng/ml IL-34 group than in oxLDL group (0.23±0.04 μg/μl vs 0.14±0.02μg/μl,P＜0.05;0.12±0.02 μg/μl vs 0.06±0.05 μg/μl,P＜0.05).The expression of ACAT-1 protein and mRNA was upregulated (P＜0.05) whereas no significant change was found in the expression of nCEH protein and mRNA (P＞0.05).Conclusion IL-34 (50 ng/ml) increases cholesterol level in macrophages by upregulating the ACAT 1-mediated esterification of free cholesterol in macrophages.