MG132, a proteasome inhibitor, enhances LDL uptake in HepG2 cells in vitro by regulating LDLR and PCSK9 expression

doi:10.1038/aps.2014.52

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	MG132, a proteasome inhibitor, enhances LDL uptake in HepG2 cells in vitro by regulating LDLR and PCSK9 expression
	Yan, Hong; Ma, Yan-ling; Gui, Yu-zhou; Wang, Shu-mei; Wang, Xin-bo; Gao, Fei; Wang, Yi-ping
刊名	ACTA PHARMACOLOGICA SINICA
	2014-08
卷号	35 期号:8 页码:994-1004
关键词	cholesterol homeostasis LDLR MG132 proteasome inhibition PKC PCSK9 pravastatin HepG2 cells
ISSN号	1671-4083
DOI	10.1038/aps.2014.52
文献子类	Article
英文摘要	Aim: Expression of liver low-density lipoprotein receptor (LDLR), a determinant regulator in cholesterol homeostasis, is tightly controlled at multiple levels. The aim of this study was to examine whether proteasome inhibition could affect LDLR expression and LDL uptake in liver cells in vitro. Methods: HepG2 cells were examined. Real-time PCR and Western blot analysis were used to determine the mRNA and protein levels, respectively. Dil-LDL uptake assay was used to quantify the LDLR function. Luciferase assay system was used to detect the activity of proprotein convertase subtilisin/kexin type 9 (PCSK9, a major protein mediating LDLR degradation) promoter. Specific siRNAs were used to verify the involvement of PCSK9. Results: Treatment of HepG2 cells with the specific proteasome inhibitor MG132 (0.03-3 mu mol/L) dose-dependently increased LDLR mRNA and protein levels, as well as LDL uptake. Short-term treatment with MG132 (0.3 mu mol/L, up to 8 h) significantly increased both LDLR mRNA and protein levels in HepG2 cells, which was blocked by the specific PKC inhibitors GF 109203X, Go 6983 or staurosporine. In contrast, a longer treatment with MG132 (0.3 mu mol/L, 24 h) did not change LDLR mRNA, but markedly increased LDLR protein by reducing PCSK9-mediated lysosome LDLR degradation. Furthermore, MG132 time-dependently suppressed PCSK9 expression in the HepG2 cells through a SREBP-1c related pathway. Combined treatment with MG132 (0.3 mu mol/L) and pravastatin (5 mu mol/L) strongly promoted LDLR expression and LDL uptake in HepG2 cells, and blocked the upregulation of PCSK9 caused by pravastatin alone. Conclusion: Inhibition of proteasome by MG132 in HepG2 cells plays dual roles in LDLR and PCSK9 expression, and exerts a beneficial effect on cholesterol homeostasis.
WOS关键词	PROTEIN-KINASE-C ; SUBTILISIN/KEXIN TYPE 9 ; RECEPTOR ; CHOLESTEROL ; PATHWAY ; ELEMENT ; GENE ; TRANSCRIPTION ; EPSILON ; TARGET
WOS研究方向	Chemistry ; Pharmacology & Pharmacy
语种	英语
CSCD记录号	CSCD:5206234
出版者	ACTA PHARMACOLOGICA SINICA
WOS记录号	WOS:000340510400002
内容类型	期刊论文
源URL	[http://119.78.100.183/handle/2S10ELR8/276957]
专题	药理学第一研究室中科院受体结构与功能重点实验室新药研究国家重点实验室
通讯作者	Wang, Yi-ping
作者单位	Chinese Acad Sci, Shanghai Inst Mat Med, State Key Lab Drug Res, Shanghai 201203, Peoples R China
推荐引用方式 GB/T 7714	Yan, Hong,Ma, Yan-ling,Gui, Yu-zhou,et al. MG132, a proteasome inhibitor, enhances LDL uptake in HepG2 cells in vitro by regulating LDLR and PCSK9 expression[J]. ACTA PHARMACOLOGICA SINICA,2014,35(8):994-1004.
APA	Yan, Hong.,Ma, Yan-ling.,Gui, Yu-zhou.,Wang, Shu-mei.,Wang, Xin-bo.,...&Wang, Yi-ping.(2014).MG132, a proteasome inhibitor, enhances LDL uptake in HepG2 cells in vitro by regulating LDLR and PCSK9 expression.ACTA PHARMACOLOGICA SINICA,35(8),994-1004.
MLA	Yan, Hong,et al."MG132, a proteasome inhibitor, enhances LDL uptake in HepG2 cells in vitro by regulating LDLR and PCSK9 expression".ACTA PHARMACOLOGICA SINICA 35.8(2014):994-1004.