HDAC3 interacts with sumoylated C/EBP¦Á to negatively regulate the LXR¦Á expression in rat hepatocytes

详细信息    查看全文

• 作者：Juan Ren^a ; ^b ; Dongmin Li^a ; ^b ; Yue Li^a ; ^b ; Xi Lan^a ; ^b ; Jianhuai Zheng^c ; Xuan Wang^d ; Jie Ma^a ; ^b ; Shemin Lu^a ; ^b ; ^e ; ^{shemin.lu@gmail.com}
• 关键词：CBS ; C/EBP¦Á binding site ; C/EBPs ; CCAAT/enhancer binding proteins ; ChIP ; chromatin immunoprecipitation assay ; Co-IP ; co-immunoprecipitation ; CYP7A1 ; cholesterol 7¦Á-hydroxylase ; FAS ; fatty acid synthase ; HDAC ; histone deacetylase ; HFD-MetS ; high-fat-diet
• 刊名：Molecular and Cellular Endocrinology
• 出版年：2013
• 出版时间：15 July, 2013
• 年：2013
• 卷：374
• 期：1-2
• 页码：35-45
• 全文大小：2486 K

文摘

The expression changes of liver X receptor alpha (LXR¦Á), histone deacetylase 3 (HDAC3) and CCAAT/enhancer binding protein alpha (C/EBP¦Á) were detected in liver tissues of our high-fat-diet E3 rat model. The aim of this study is to pinpoint the molecular mechanism of HDAC3 and C/EBP¦Á to orchestrate LXR¦Á expression in hepatocytes. We confirmed that LXR¦Á and its target genes were negatively regulated by HDAC3 in stable expressed clones with pEGFP-Hdac3 or shRNA-Hdac3 vector. However, transient pEGFP-C/EBP¦Á plasmid transfection showed an upregulation of LXR¦Á expression and C/EBP¦Á enhanced LXR¦Á promoter activity in a dose-dependent manner in CBRH-7919 cells. By using 5¡ä-serial deletion reporter analysis, we identified that fragment from ?2881 to ?1181 bp of LXR¦Á promoter was responsible for C/EBP¦Á binding to the promoter, especially CBS1 and CBS4 were identified essentially by using ChIP and luciferase reporter assay. Co-IP, qRT-PCR and ChIP revealed that HDAC3 interacted with C/EBP¦Á co-regulated LXR¦Á expression. Sumoylation of C/EBP¦Á at lysine 159 was detected in CBRH-7919 cells with transient overexpressed C/EBP¦Á, and Co-IP assay detected that sumoylated C/EBP¦Á interacted with more HDAC3 than C/EBP¦Á K159L mutant. Luciferase reporter assay demonstrated that C/EBP¦Á participated in HDAC3-repressed LXR¦Á transcription, and HDAC3 was involved in sumoylated C/EBP¦Á-inactivated LXR¦Á activity. Luciferase reporter assay demonstrated that sumoylation of C/EBP¦Á by SUMO-1 directly reversed the activation of C/EBP¦Á on LXR¦Á promoter. The results suggested that HDAC3 interacts with sumoylated C/EBP¦Á to negatively regulate the LXR¦Á expression.