title: HDAC3 interacts with sumoylated C/EBPα to negatively regulate the LXRα expression in rat hepatocytes.
abstract: The expression changes of liver X receptor alpha (LXRα), histone deacetylase 3 (HDAC3) and CCAAT/enhancer binding protein alpha (C/EBPα) 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/EBPα to orchestrate LXRα expression in hepatocytes. We confirmed that LXRα and its target genes were negatively regulated by HDAC3 in stable expressed clones with pEGFP-Hdac3 or shRNA-Hdac3 vector. However, transient pEGFP-C/EBPα plasmid transfection showed an upregulation of LXRα expression and C/EBPα enhanced LXRα promoter activity in a dose-dependent manner in CBRH-7919 cells. By using 5'-serial deletion reporter analysis, we identified that fragment from -2881 to -1181bp of LXRα promoter was responsible for C/EBPα 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/EBPα co-regulated LXRα expression. Sumoylation of C/EBPα at lysine 159 was detected in CBRH-7919 cells with transient overexpressed C/EBPα, and Co-IP assay detected that sumoylated C/EBPα interacted with more HDAC3 than C/EBPα K159L mutant. Luciferase reporter assay demonstrated that C/EBPα participated in HDAC3-repressed LXRα transcription, and HDAC3 was involved in sumoylated C/EBPα-inactivated LXRα activity. Luciferase reporter assay demonstrated that sumoylation of C/EBPα by SUMO-1 directly reversed the activation of C/EBPα on LXRα promoter. The results suggested that HDAC3 interacts with sumoylated C/EBPα to negatively regulate the LXRα expression.
authors: Department of Genetics and Molecular Biology, Xi'an Jiaotong University College of Medicine, Xi'an, Shaanxi 710061, PR China.
authors: Juan
authors: J
authors: Ren
authors: Dongmin
authors: D
authors: Li
authors: Yue
authors: Y
authors: Li
authors: Xi
authors: X
authors: Lan
authors: Jianhuai
authors: J
authors: Zheng
authors: Xuan
authors: X
authors: Wang
authors: Jie
authors: J
authors: Ma
authors: Shemin
authors: S
authors: Lu
mesh_terms: D000818:Animals; D001665:Binding Sites; D022763:CCAAT-Enhancer-Binding Protein-alpha / Q000235:genetics* / Q000378:metabolism; D045744:Cell Line, Tumor; D059305:Diet, High-Fat; D005786:Gene Expression Regulation; D017930:Genes, Reporter; D022781:Hepatocytes / Q000166:cytology / Q000378:metabolism*; D006655:Histone Deacetylases / Q000235:genetics* / Q000378:metabolism; D000071518:Liver X Receptors; D008156:Luciferases; D057093:Orphan Nuclear Receptors / Q000235:genetics* / Q000378:metabolism; D011401:Promoter Regions, Genetic; D011485:Protein Binding; D051381:Rats; D015398:Signal Transduction; D058207:Sumoylation; D015534:Trans-Activators / Q000235:genetics / Q000378:metabolism; D000099186:Histone Deacetylase 3
chemical_list: D022763:CCAAT-Enhancer-Binding Protein-alpha; D006655:Histone Deacetylases; D000071518:Liver X Receptors; D008156:Luciferases; D057093:Orphan Nuclear Receptors; D015534:Trans-Activators; D000099186:Histone Deacetylase 3; C000605215:Nr1h3 protein, rat