肺炎衣原体通过上调酰基辅酶A：胆固醇酰基转移酶1的表达诱导THP-1来源的泡沫细胞形成

[Chlamydia pneumoniae induces THP-1-derived foam cell formation by up-regulating the expression of acyl-coenzyme A: cholesterol acyltransferase 1].

作者信息

He Ping, Mei Chun-li, Cheng Bei, Liu Wei, Wang Yan-fu, Wan Jing-jing

机构信息

Department of Gerontology, Union Hospital of Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.

出版信息

Zhonghua Xin Xue Guan Bing Za Zhi. 2009 May;37(5):430-5.

PMID:19781220

Abstract

OBJECTIVE

To investigate the expression changes of acyl-coenzyme A: cholesterol acyltransferase 1 (ACAT1) on Chlamydia pneumoniae (C.pn) induced foam cell formation.

METHODS

Human monocytic cell line (THP-1) was induced into macrophages by 160 nmol/L phorbol myristate acetate (PMA) for 48 h, and were randomly allocated into four groups: negative control group (50 microg/ml LDL for 48 h); positive control group (50 microg/ml ox-LDL for 48 h); C.pn infection group (50 microg/ml LDL plus 1 x 10(5), 4 x 10(5), 5 x 10(5) and 1 x 10(6) IFU C.pn for 48 h or 1 x 10(6) IFU C.pn for 0, 24, 48 and 72 h); ACAT inhibitor 58-035 plus C.pn infection group (1, 5, 10 microg/ml ACAT inhibitor 58-035 pretreatment for 1 h, 50 microg/ml LDL and 1 x 10(6) IFU C.pn for 48 h). The mRNA and protein expressions of ACAT1 were determined by RT-PCR and Western blot, respectively. Lipid droplets in cytoplasm were observed by oil red O staining. The contents of intracellular cholesteryl esters were detected by enzyme-fluorescence.

RESULTS

The mRNA and protein expressions of ACAT1 were significantly up-regulated in positive control cells compared those in negative control cells and further upregulated by C.pn infection in a time-dependent and concentration-dependent manner (all P < 0.05). There were significantly increases in the accumulation of lipid droplets and the ratio of cholesteryl ester to total cholesterol in positive control cells as compared with negative control cells and these were further aggravated by C.pn (at the concentrations of 5 x 10(5) and 1 x 10(6) IFU for 48 h) and C.pn infection induced increases in the accumulation of lipid droplets and the ratio of cholesteryl ester to total cholesterol could be significantly attenuated by ACAT inhibitor 58-035 (all P < 0.05).

CONCLUSION

Chlamydia pneumoniae induces THP-1-derived foam cell formation by up-regulating the expression of ACAT1.

摘要

目的

研究酰基辅酶A：胆固醇酰基转移酶1（ACAT1）在肺炎衣原体（C.pn）诱导的泡沫细胞形成中的表达变化。

方法

用160 nmol/L佛波酯（PMA）将人单核细胞系（THP-1）诱导为巨噬细胞48小时，然后随机分为四组：阴性对照组（50 μg/ml低密度脂蛋白处理48小时）；阳性对照组（50 μg/ml氧化低密度脂蛋白处理48小时）；C.pn感染组（50 μg/ml低密度脂蛋白分别加1×10⁵、4×10⁵、5×10⁵和1×10⁶感染复数（IFU）的C.pn处理48小时，或1×10⁶ IFU的C.pn处理0、24、48和72小时）；ACAT抑制剂58-035加C.pn感染组（1、5、10 μg/ml的ACAT抑制剂58-035预处理1小时，50 μg/ml低密度脂蛋白和1×10⁶ IFU的C.pn处理48小时）。分别用逆转录聚合酶链反应（RT-PCR）和蛋白质印迹法检测ACAT1的mRNA和蛋白表达。用油红O染色观察细胞质中的脂滴。用酶荧光法检测细胞内胆固醇酯的含量。

结果

与阴性对照组相比，阳性对照组细胞中ACAT1的mRNA和蛋白表达显著上调，且C.pn感染以时间和浓度依赖性方式进一步上调（均P<0.05）。与阴性对照组相比，阳性对照组细胞中脂滴积累及胆固醇酯与总胆固醇的比例显著增加，并被C.pn（5×10⁵和1×10⁶ IFU处理48小时）进一步加重，而ACAT抑制剂58-035可显著减弱C.pn感染诱导的脂滴积累及胆固醇酯与总胆固醇比例的增加（均P<0.05）。