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Beinsteiner B, Billas IML, Moras D. Structural insights into the HNF4 biology. Front Endocrinol (Lausanne) 2023; 14:1197063. [PMID: 37404310 PMCID: PMC10315846 DOI: 10.3389/fendo.2023.1197063] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/30/2023] [Accepted: 06/01/2023] [Indexed: 07/06/2023] Open
Abstract
Hepatocyte Nuclear Factor 4 (HNF4) is a transcription factor (TF) belonging to the nuclear receptor (NR) family that is expressed in liver, kidney, intestine and pancreas. It is a master regulator of liver-specific gene expression, in particular those genes involved in lipid transport and glucose metabolism and is crucial for the cellular differentiation during development. Dysregulation of HNF4 is linked to human diseases, such as type I diabetes (MODY1) and hemophilia. Here, we review the structures of the isolated HNF4 DNA binding domain (DBD) and ligand binding domain (LBD) and that of the multidomain receptor and compare them with the structures of other NRs. We will further discuss the biology of the HNF4α receptors from a structural perspective, in particular the effect of pathological mutations and of functionally critical post-translational modifications on the structure-function of the receptor.
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Affiliation(s)
- Brice Beinsteiner
- Laboratory IGBMC (Institute of Genetics and of Molecular and Cellular Biology), Centre for Integrative Biology (CBI), Illkirch, France
- Université de Strasbourg (Unistra), Strasbourg, France
- Institut National de la Santé et de la Recherche Médicale (INSERM) U1258, Illkirch, France
- Centre National de la Recherche Scientifique (CNRS) UMR 7104, Illkirch, France
| | - Isabelle M. L. Billas
- Laboratory IGBMC (Institute of Genetics and of Molecular and Cellular Biology), Centre for Integrative Biology (CBI), Illkirch, France
- Université de Strasbourg (Unistra), Strasbourg, France
- Institut National de la Santé et de la Recherche Médicale (INSERM) U1258, Illkirch, France
- Centre National de la Recherche Scientifique (CNRS) UMR 7104, Illkirch, France
| | - Dino Moras
- Laboratory IGBMC (Institute of Genetics and of Molecular and Cellular Biology), Centre for Integrative Biology (CBI), Illkirch, France
- Université de Strasbourg (Unistra), Strasbourg, France
- Institut National de la Santé et de la Recherche Médicale (INSERM) U1258, Illkirch, France
- Centre National de la Recherche Scientifique (CNRS) UMR 7104, Illkirch, France
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2
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Abstract
Non-alcoholic fatty liver disease (NAFLD) is emerging as the most common chronic liver disease worldwide. It refers to a range of liver conditions affecting people who drink little or no alcohol. NAFLD comprises non-alcoholic fatty liver and non-alcoholic steatohepatitis (NASH), the more aggressive form of NAFLD. NASH is featured by steatosis, lobular inflammation, hepatocyte injury, and various degrees of fibrosis. Although much progress has been made over the past decades, the pathogenic mechanism of NAFLD remains to be fully elucidated. Hepatocyte nuclear factor 4α (HNF4α) is a nuclear hormone receptor that is highly expressed in hepatocytes. Hepatic HNF4α expression is markedly reduced in NAFLD patients and mouse models of NASH. HNF4α has been shown to regulate bile acid, lipid, glucose, and drug metabolism. In this review, we summarize the recent advances in the understanding of the pathogenesis of NAFLD with a focus on the regulation of HNF4α and the role of hepatic HNF4α in NAFLD. Several lines of evidence have shown that hepatic HNF4α plays a key role in the initiation and progression of NAFLD. Recent data suggest that hepatic HNF4α may be a promising target for treatment of NAFLD.
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3
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Diaz-Aragon R, Coard MC, Amirneni S, Faccioli L, Haep N, Malizio MR, Motomura T, Kocas-Kilicarslan ZN, Ostrowska A, Florentino RM, Frau C. Therapeutic Potential of HNF4α in End-stage Liver Disease. Organogenesis 2021; 17:126-135. [PMID: 35114889 DOI: 10.1080/15476278.2021.1994273] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022] Open
Abstract
The prevalence of end-stage liver disease (ESLD) in the US is increasing at an alarming rate. It can be caused by several factors; however, one of the most common routes begins with nonalcoholic fatty liver disease (NAFLD). ESLD is diagnosed by the presence of irreversible damage to the liver. Currently, the only definitive treatment for ESLD is orthotopic liver transplantation (OLT). Nevertheless, OLT is limited due to a shortage of donor livers. Several promising alternative treatment options are under investigation. Researchers have focused on the effect of liver-enriched transcription factors (LETFs) on disease progression. Specifically, hepatocyte nuclear factor 4-alpha (HNF4α) has been reported to reset the liver transcription network and possibly play a role in the regression of fibrosis and cirrhosis. In this review, we describe the function of HNF4α, along with its regulation at various levels. In addition, we summarize the role of HNF4α in ESLD and its potential as a therapeutic target in the treatment of ESLD.
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Affiliation(s)
- Ricardo Diaz-Aragon
- Department of Pathology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
| | - Michael C Coard
- Department of Pathology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
| | - Sriram Amirneni
- Department of Pathology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
| | - Lanuza Faccioli
- Department of Pathology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
| | - Nils Haep
- Department of Pathology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
| | - Michelle R Malizio
- Department of Pathology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
| | - Takashi Motomura
- Department of Pathology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
| | | | - Alina Ostrowska
- Department of Pathology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA.,Pittsburgh Liver Research Center, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Rodrigo M Florentino
- Department of Pathology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
| | - Carla Frau
- Department of Pathology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
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4
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Kumari A, Mittal L, Srivastava M, Pathak DP, Asthana S. Conformational Characterization of the Co-Activator Binding Site Revealed the Mechanism to Achieve the Bioactive State of FXR. Front Mol Biosci 2021; 8:658312. [PMID: 34532338 PMCID: PMC8439381 DOI: 10.3389/fmolb.2021.658312] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2021] [Accepted: 07/14/2021] [Indexed: 12/12/2022] Open
Abstract
FXR bioactive states are responsible for the regulation of metabolic pathways, which are modulated by agonists and co-activators. The synergy between agonist binding and ‘co-activator’ recruitment is highly conformationally driven. The characterization of conformational dynamics is essential for mechanistic and therapeutic understanding. To shed light on the conformational ensembles, dynamics, and structural determinants that govern the activation process of FXR, molecular dynamic (MD) simulation is employed. Atomic insights into the ligand binding domain (LBD) of FXR revealed significant differences in inter/intra molecular bonding patterns, leading to structural anomalies in different systems of FXR. The sole presence of an agonist or ‘co-activator’ fails to achieve the essential bioactive conformation of FXR. However, the presence of both establishes the bioactive conformation of FXR as they modulate the internal wiring of key residues that coordinate allosteric structural transitions and their activity. We provide a precise description of critical residue positioning during conformational changes that elucidate the synergy between its binding partners to achieve an FXR activation state. Our study offers insights into the associated modulation occurring in FXR at bound and unbound forms. Thereafter, we also identified hot-spots that are critical to arrest the activation mechanism of FXR that would be helpful for the rational design of its agonists.
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Affiliation(s)
- Anita Kumari
- Translational Health Science and Technology Institute (THSTI), Faridabad, India.,Department of Pharmaceutical Chemistry, Delhi Pharmaceutical Sciences and Research University (DPSRU), New Delhi, India
| | - Lovika Mittal
- Translational Health Science and Technology Institute (THSTI), Faridabad, India
| | - Mitul Srivastava
- Translational Health Science and Technology Institute (THSTI), Faridabad, India
| | - Dharam Pal Pathak
- Department of Pharmaceutical Chemistry, Delhi Pharmaceutical Sciences and Research University (DPSRU), New Delhi, India.,Delhi Institute of Pharmaceutical Sciences and Research (DIPSAR), New Delhi, India
| | - Shailendra Asthana
- Translational Health Science and Technology Institute (THSTI), Faridabad, India
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5
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Zhang J, Yang Y, Liu H, Hu H. Src-1 and SP2 promote the proliferation and epithelial-mesenchymal transition of nasopharyngeal carcinoma. Open Med (Wars) 2021; 16:1061-1069. [PMID: 34307888 PMCID: PMC8284335 DOI: 10.1515/med-2021-0248] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Revised: 01/09/2021] [Accepted: 02/08/2021] [Indexed: 12/14/2022] Open
Abstract
Nasopharyngeal carcinoma (NPC) is characterized by high morbidity and morality, especially in Southern China. Transcription factors intensively participate in the initiation and development of NPC. This study aimed to investigate the roles of Src-1 in NPC. mRNA level was determined by qRT-PCR. Western blot was carried out for the protein level. CCK-8 assay was performed to determine cell viability, colony formation for NPC cell proliferation, and transwell for cell migration and invasion ability. The results showed Steroid receptor coactivator 1 (Src-1) was overexpressed in SNE-2 and 6-10B. The expression of Src-1 and SP2 was in positive correlation. Overexpression of Src-1 promoted the cell viability, colony formation, and epithelial-mesenchymal transition (EMT), manifested by the increase of migration and invasion ability, while knockdown of Src-1 exerted opposite effects. Additionally, knockdown or overexpression of SP2 reversed the effects of overexpressed or downregulated Src-1, which was reversed by the depletion of SP2. Moreover, Src-1 interacted with SP2 to regulate EMT-related genes such as E-cad, N-cad, Vimentin, and ZEB1, and proliferation- and apoptosis-related genes, such as bax, cytochrome c, and cleaved caspase3 and bcl-2. Thus, blocking the interaction between Src-1 and SP2 may be a therapeutic target for inhibiting the metastasis of NPC.
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Affiliation(s)
- Jingjing Zhang
- Ear, Nose, Throat Department, Peking University Shenzhen Hospital, Shenzhen, Guangdong 518000, China
| | - Yuanyuan Yang
- Ear, Nose, Throat Department, Peking University Shenzhen Hospital, Shenzhen, Guangdong 518000, China
| | - Hongyu Liu
- Ear, Nose, Throat Department, Peking University Shenzhen Hospital, Shenzhen, Guangdong 518000, China
| | - Hongyi Hu
- Ear, Nose, Throat Department, Peking University Shenzhen Hospital, Shenzhen, Guangdong 518000, China
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Li S, Zhu Y, Li R, Huang J, You K, Yuan Y, Zhuang S. LncRNA Lnc-APUE is Repressed by HNF4 α and Promotes G1/S Phase Transition and Tumor Growth by Regulating MiR-20b/E2F1 Axis. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2021; 8:2003094. [PMID: 33854885 PMCID: PMC8025008 DOI: 10.1002/advs.202003094] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/12/2020] [Revised: 12/07/2020] [Indexed: 06/07/2023]
Abstract
Many long noncoding RNAs (lncRNAs) have been annotated, but their functions remain unknown. The authors found a novel lnc-APUE (lncRNA accelerating proliferation by upregulating E2F1) that is upregulated in different cancer types, including hepatocellular carcinoma (HCC), and high lnc-APUE level is associated with short recurrence-free survival (RFS) of HCC patients. Gain- and loss-of-function analyses showed that lnc-APUE accelerated G1/S transition and tumor cell growth in vitro and allows hepatoma xenografts to grow faster in vivo. Mechanistically, lnc-APUE binds to miR-20b and relieves its repression on E2F1 expression, resulting in increased E2F1 level and accelerated G1/S phase transition and cell proliferation. Consistently, lnc-APUE level is positively associated with the expression of E2F1 and its downstream target genes in HCC tissues. Further investigations disclose that hepatocyte nuclear factor 4 alpha (HNF4α) binds to the lnc-APUE promoter, represses lnc-APUE transcription, then diminishes E2F1 expression and cell proliferation. HNF4α expression is reduced in HCC tissues and low HNF4α level is correlated with high lnc-APUE expression. Collectively, a HNF4α/lnc-APUE/miR-20b/E2F1 axis in which HNF4α represses lnc-APUE expression and keeps E2F1 at a low level is identified. In tumor cells, HNF4α downregulation leads to lnc-APUE upregulation, which prevents the inhibition of miR-20b on E2F1 expression and thereby promotes cell cycle progression and tumor growth.
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Affiliation(s)
- Song‐Yang Li
- MOE Key Laboratory of Gene Function and RegulationSchool of Life SciencesCollaborative Innovation Center for Cancer MedicineSun Yat‐sen UniversityGuangzhou510275China
| | - Ying Zhu
- MOE Key Laboratory of Gene Function and RegulationSchool of Life SciencesCollaborative Innovation Center for Cancer MedicineSun Yat‐sen UniversityGuangzhou510275China
| | - Ruo‐Nan Li
- MOE Key Laboratory of Gene Function and RegulationSchool of Life SciencesCollaborative Innovation Center for Cancer MedicineSun Yat‐sen UniversityGuangzhou510275China
| | - Jia‐Hui Huang
- MOE Key Laboratory of Gene Function and RegulationSchool of Life SciencesCollaborative Innovation Center for Cancer MedicineSun Yat‐sen UniversityGuangzhou510275China
| | - Kai You
- MOE Key Laboratory of Gene Function and RegulationSchool of Life SciencesCollaborative Innovation Center for Cancer MedicineSun Yat‐sen UniversityGuangzhou510275China
| | - Yun‐Fei Yuan
- Department of Hepatobilliary OncologyCancer CenterSun Yat‐sen UniversityGuangzhou510060China
| | - Shi‐Mei Zhuang
- MOE Key Laboratory of Gene Function and RegulationSchool of Life SciencesCollaborative Innovation Center for Cancer MedicineSun Yat‐sen UniversityGuangzhou510275China
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Control of Cell Identity by the Nuclear Receptor HNF4 in Organ Pathophysiology. Cells 2020; 9:cells9102185. [PMID: 32998360 PMCID: PMC7600215 DOI: 10.3390/cells9102185] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2020] [Revised: 09/25/2020] [Accepted: 09/26/2020] [Indexed: 12/14/2022] Open
Abstract
Hepatocyte Nuclear Factor 4 (HNF4) is a transcription factor (TF) belonging to the nuclear receptor family whose expression and activities are restricted to a limited number of organs including the liver and gastrointestinal tract. In this review, we present robust evidence pointing to HNF4 as a master regulator of cellular differentiation during development and a safekeeper of acquired cell identity in adult organs. Importantly, we discuss that transient loss of HNF4 may represent a protective mechanism upon acute organ injury, while prolonged impairment of HNF4 activities could contribute to organ dysfunction. In this context, we describe in detail mechanisms involved in the pathophysiological control of cell identity by HNF4, including how HNF4 works as part of cell-specific TF networks and how its expression/activities are disrupted in injured organs.
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8
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Bi Y, Wang Y, Xie W. The interplay between hepatocyte nuclear factor 4α (HNF4α) and cholesterol sulfotransferase (SULT2B1b) in hepatic energy homeostasis. LIVER RESEARCH 2019. [DOI: 10.1016/j.livres.2019.09.004] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/16/2023]
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9
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Thakur A, Wong JCH, Wang EY, Lotto J, Kim D, Cheng JC, Mingay M, Cullum R, Moudgil V, Ahmed N, Tsai SH, Wei W, Walsh CP, Stephan T, Bilenky M, Fuglerud BM, Karimi MM, Gonzalez FJ, Hirst M, Hoodless PA. Hepatocyte Nuclear Factor 4-Alpha Is Essential for the Active Epigenetic State at Enhancers in Mouse Liver. Hepatology 2019; 70:1360-1376. [PMID: 30933372 PMCID: PMC6773525 DOI: 10.1002/hep.30631] [Citation(s) in RCA: 45] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/29/2018] [Accepted: 03/27/2019] [Indexed: 12/11/2022]
Abstract
Cell-fate determination is influenced by interactions between master transcription factors (TFs) and cis-regulatory elements. Hepatocyte nuclear factor 4 alpha (HNF4A), a liver-enriched TF, acts as a master controller in specification of hepatic progenitor cells by regulating a network of TFs to control onset of hepatocyte cell fate. Using analysis of genome-wide histone modifications, DNA methylation, and hydroxymethylation in mouse hepatocytes, we show that HNF4A occupies active enhancers in hepatocytes and is essential for active histone and DNA signatures, especially acetylation of lysine 27 of histone 3 (H3K27ac) and 5-hydroxymethylcytosine (5hmC). In mice lacking HNF4A protein in hepatocytes, we observed a decrease in both H3K27ac and hydroxymethylation at regions bound by HNF4A. Mechanistically, HNF4A-associated hydroxymethylation (5hmC) requires its interaction with ten-eleven translocation methylcytosine dioxygenase 3 (TET3), a protein responsible for oxidation from 5mC to 5hmC. Furthermore, HNF4A regulates TET3 expression in liver by directly binding to an enhancer region. Conclusion: In conclusion, we identified that HNF4A is required for the active epigenetic state at enhancers that amplifies transcription of genes in hepatocytes.
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Affiliation(s)
- Avinash Thakur
- Terry Fox Laboratory, BC Cancer, Vancouver, British Columbia, Canada, V5Z 1L3,Department of Medical Genetics, University of British Columbia, Vancouver, Canada, V6T 1Z4
| | - Jasper C. H. Wong
- Department of Microbiology and Immunology, Michael Smith Laboratories Centre for High-Throughput Biology, University of British Columbia, Vancouver, British Columbia, Canada
| | - Evan Y. Wang
- Terry Fox Laboratory, BC Cancer, Vancouver, British Columbia, Canada, V5Z 1L3
| | - Jeremy Lotto
- Terry Fox Laboratory, BC Cancer, Vancouver, British Columbia, Canada, V5Z 1L3
| | - Donghwan Kim
- Center of Cancer Research, National Cancer Institute, Bethesda MD 2089
| | - Jung-Chien Cheng
- Terry Fox Laboratory, BC Cancer, Vancouver, British Columbia, Canada, V5Z 1L3
| | - Matthew Mingay
- Department of Microbiology and Immunology, Michael Smith Laboratories Centre for High-Throughput Biology, University of British Columbia, Vancouver, British Columbia, Canada
| | - Rebecca Cullum
- Terry Fox Laboratory, BC Cancer, Vancouver, British Columbia, Canada, V5Z 1L3
| | - Vaishali Moudgil
- Terry Fox Laboratory, BC Cancer, Vancouver, British Columbia, Canada, V5Z 1L3
| | - Nafeel Ahmed
- Terry Fox Laboratory, BC Cancer, Vancouver, British Columbia, Canada, V5Z 1L3
| | - Shu-Huei Tsai
- Terry Fox Laboratory, BC Cancer, Vancouver, British Columbia, Canada, V5Z 1L3
| | - Wei Wei
- Terry Fox Laboratory, BC Cancer, Vancouver, British Columbia, Canada, V5Z 1L3
| | - Colum P. Walsh
- Genomic Medicine Research Group, Centre for Molecular Biosciences, Biomedical Sciences Research Institute, Ulster University, Coleraine, BT52 1SA, UK
| | - Tabea Stephan
- Terry Fox Laboratory, BC Cancer, Vancouver, British Columbia, Canada, V5Z 1L3
| | - Misha Bilenky
- Genome Sciences Centre, BC Cancer, Vancouver, British Columbia, Canada
| | - Bettina M. Fuglerud
- Terry Fox Laboratory, BC Cancer, Vancouver, British Columbia, Canada, V5Z 1L3,Department of Biosciences, University of Oslo, Oslo, Norway, 0316
| | | | - Frank J. Gonzalez
- Center of Cancer Research, National Cancer Institute, Bethesda MD 2089
| | - Martin Hirst
- Department of Microbiology and Immunology, Michael Smith Laboratories Centre for High-Throughput Biology, University of British Columbia, Vancouver, British Columbia, Canada,Genome Sciences Centre, BC Cancer, Vancouver, British Columbia, Canada
| | - Pamela A. Hoodless
- Terry Fox Laboratory, BC Cancer, Vancouver, British Columbia, Canada, V5Z 1L3,Department of Medical Genetics, University of British Columbia, Vancouver, Canada, V6T 1Z4,School of Biomedical Engineering, University of British Columbia, Vancouver, Canada, V6T 1Z4
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10
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Possible involvement of the competition for the transcriptional coactivator glucocorticoid receptor-interacting protein 1 in the inflammatory signal-dependent suppression of PXR-mediated CYP3A induction in vitro. Drug Metab Pharmacokinet 2019; 34:272-279. [DOI: 10.1016/j.dmpk.2019.04.005] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2019] [Revised: 04/08/2019] [Accepted: 04/15/2019] [Indexed: 12/13/2022]
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11
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Han EH, Singh P, Lee IK, Urrutia R, Chi YI. ErbB3-binding protein 1 (EBP1) represses HNF4α-mediated transcription and insulin secretion in pancreatic β-cells. J Biol Chem 2019; 294:13983-13994. [PMID: 31362984 DOI: 10.1074/jbc.ra119.009558] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2019] [Revised: 07/18/2019] [Indexed: 12/13/2022] Open
Abstract
HNF4α (hepatocyte nuclear factor 4α) is one of the master regulators of pancreatic β-cell development and function, and mutations in the HNF4α gene are well-known monogenic causes of diabetes. As a member of the nuclear receptor family, HNF4α exerts its gene regulatory function through various molecular interactions; however, there is a paucity of knowledge of the different functional complexes in which HNF4α participates. Here, to find HNF4α-binding proteins in pancreatic β-cells, we used yeast two-hybrid screening, a mammalian two-hybrid assay, and glutathione S-transferase pulldown approaches, which identified EBP1 (ErbB3-binding protein 1) as a factor that binds HNF4α in a LXXLL motif-mediated manner. In the β-cells, EBP1 suppressed the expression of HNF4α target genes that are implicated in insulin secretion, which is impaired in HNF4α mutation-driven diabetes. The crystal structure of the HNF4α ligand-binding domain in complex with a peptide harboring the EBP1 LXXLL motif at 3.15Å resolution hinted at the molecular basis of the repression. The details of the structure suggested that EBP1's LXXLL motif competes with HNF4α coactivators for the same binding pocket and thereby prevents recruitment of additional transcriptional coactivators. These findings provide further evidence that EBP1 plays multiple cellular roles and is involved in nuclear receptor-mediated gene regulation. Selective disruption of the HNF4α-EBP1 interaction or tissue-specific EBP1 inactivation can enhance HNF4α activities and thereby improve insulin secretion in β-cells, potentially representing a new strategy for managing diabetes and related metabolic disorders.
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Affiliation(s)
- Eun Hee Han
- Section of Structural Biology, Hormel Institute, University of Minnesota, Austin, Minnesota 55912.,Drug & Disease Target Group, Division of Life Science, Korea Basic Science Institute, Cheongju 28119, Republic of Korea
| | - Puja Singh
- Section of Structural Biology, Hormel Institute, University of Minnesota, Austin, Minnesota 55912
| | - In-Kyu Lee
- Department of Internal Medicine, School of Medicine, Kyungpook National University, Kyungpook National University Hospital, Daegu 41944, Republic of Korea
| | - Raul Urrutia
- Genomic Sciences and Precision Medicine Center, Medical College of Wisconsin, Division of Research, Department of Surgery, Medical College of Wisconsin, Milwaukee, Wisconsin 53226
| | - Young-In Chi
- Section of Structural Biology, Hormel Institute, University of Minnesota, Austin, Minnesota 55912 .,Genomic Sciences and Precision Medicine Center, Medical College of Wisconsin, Division of Research, Department of Surgery, Medical College of Wisconsin, Milwaukee, Wisconsin 53226
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12
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Sun Q, Xu W, Ji S, Qin Y, Liu W, Hu Q, Zhang Z, Liu M, Yu X, Xu X. Role of hepatocyte nuclear factor 4 alpha in cell proliferation and gemcitabine resistance in pancreatic adenocarcinoma. Cancer Cell Int 2019; 19:49. [PMID: 30867652 PMCID: PMC6398265 DOI: 10.1186/s12935-019-0767-4] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2019] [Accepted: 02/28/2019] [Indexed: 01/03/2023] Open
Abstract
Background Hepatocyte nuclear factor 4α (HNF4α) is a tissue-specific transcription factor that regulates the expression of numerous genes in hepatocytes and pancreatic β cells. HNF4α has been reported to affect cell proliferation and chemoresistance in several cancers. However, the role of HNF4α in pancreatic adenocarcinoma (PDAC) has not been studied extensively and remains unclear. Methods By utilizing immunohistochemical (IHC) staining, we measured the expression of HNF4α in PDAC tissues. By silencing HNF4α in PDAC cell lines, we assessed the impact of HNF4α on pancreatic cancer cell proliferation and gemcitabine sensitivity. We used CCK8 and colony formation assays to examine the effect of HNF4α on cell proliferation. A flow cytometry assay was used to assess cell apoptosis. The expression of gemcitabine-related genes was detected by quantitative real‑time PCR (qRT-PCR) and Western blotting. IHC was utilized to assess the correlation between HNF4α and human equilibrative nucleoside transporter 1 (hENT1) expression in PDAC patients. Chromatin immunoprecipitation (ChIP) and dual‑luciferase reporter assays were used to confirm that hENT1 is a target gene of HNF4α. Results Increased HNF4α expression was detected in PDAC tissues; patients with higher HNF4α expression displayed worse prognosis. To elucidate the function of HNF4α, we examined its role in pancreatic cancer cell proliferation, apoptosis and gemcitabine resistance. In HNF4α-silenced Capan-1 and MiaPaCa-2 cells, we observed decreased cell proliferation and increased sensitivity to gemcitabine compared to those of controls. The mechanism of HNF4α in gemcitabine-related chemosensitivity was then explored. In response to HNF4α silencing, the expression levels of gemcitabine-related proteins, hENT1 and deoxycytidine kinase (dCK) were significantly increased. Additionally, hENT1 was negatively correlated with HNF4α in PDAC tissue samples. Moreover, we identified hENT1 as a downstream target of HNF4α. Conclusion HNF4α is a prognostic marker for overall survival, is required for pancreatic cancer cell proliferation and promotes resistance to gemcitabine by downregulating hENT1. Therefore, targeting HNF4α might reverse gemcitabine resistance and provide novel treatment strategies for PDAC. Electronic supplementary material The online version of this article (10.1186/s12935-019-0767-4) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Qiqing Sun
- 1Department of Pancreatic Surgery, Fudan University Shanghai Cancer Center, Shanghai, 200032 China.,2Department of Oncology, Shanghai Medical College, Fudan University, Shanghai, 200032 China.,3Pancreatic Cancer Institute, Fudan University, Shanghai, 200032 China.,4Shanghai Pancreatic Cancer Institute, Shanghai, 200032 China
| | - Wenyan Xu
- 1Department of Pancreatic Surgery, Fudan University Shanghai Cancer Center, Shanghai, 200032 China.,2Department of Oncology, Shanghai Medical College, Fudan University, Shanghai, 200032 China.,3Pancreatic Cancer Institute, Fudan University, Shanghai, 200032 China.,4Shanghai Pancreatic Cancer Institute, Shanghai, 200032 China
| | - Shunrong Ji
- 1Department of Pancreatic Surgery, Fudan University Shanghai Cancer Center, Shanghai, 200032 China.,2Department of Oncology, Shanghai Medical College, Fudan University, Shanghai, 200032 China.,3Pancreatic Cancer Institute, Fudan University, Shanghai, 200032 China.,4Shanghai Pancreatic Cancer Institute, Shanghai, 200032 China
| | - Yi Qin
- 1Department of Pancreatic Surgery, Fudan University Shanghai Cancer Center, Shanghai, 200032 China.,2Department of Oncology, Shanghai Medical College, Fudan University, Shanghai, 200032 China.,3Pancreatic Cancer Institute, Fudan University, Shanghai, 200032 China.,4Shanghai Pancreatic Cancer Institute, Shanghai, 200032 China
| | - Wensheng Liu
- 1Department of Pancreatic Surgery, Fudan University Shanghai Cancer Center, Shanghai, 200032 China.,2Department of Oncology, Shanghai Medical College, Fudan University, Shanghai, 200032 China.,3Pancreatic Cancer Institute, Fudan University, Shanghai, 200032 China.,4Shanghai Pancreatic Cancer Institute, Shanghai, 200032 China
| | - Qiangsheng Hu
- 1Department of Pancreatic Surgery, Fudan University Shanghai Cancer Center, Shanghai, 200032 China.,2Department of Oncology, Shanghai Medical College, Fudan University, Shanghai, 200032 China.,3Pancreatic Cancer Institute, Fudan University, Shanghai, 200032 China.,4Shanghai Pancreatic Cancer Institute, Shanghai, 200032 China
| | - Zheng Zhang
- 1Department of Pancreatic Surgery, Fudan University Shanghai Cancer Center, Shanghai, 200032 China.,2Department of Oncology, Shanghai Medical College, Fudan University, Shanghai, 200032 China.,3Pancreatic Cancer Institute, Fudan University, Shanghai, 200032 China.,4Shanghai Pancreatic Cancer Institute, Shanghai, 200032 China
| | - Mengqi Liu
- 1Department of Pancreatic Surgery, Fudan University Shanghai Cancer Center, Shanghai, 200032 China.,2Department of Oncology, Shanghai Medical College, Fudan University, Shanghai, 200032 China.,3Pancreatic Cancer Institute, Fudan University, Shanghai, 200032 China.,4Shanghai Pancreatic Cancer Institute, Shanghai, 200032 China
| | - Xianjun Yu
- 1Department of Pancreatic Surgery, Fudan University Shanghai Cancer Center, Shanghai, 200032 China.,2Department of Oncology, Shanghai Medical College, Fudan University, Shanghai, 200032 China.,3Pancreatic Cancer Institute, Fudan University, Shanghai, 200032 China.,4Shanghai Pancreatic Cancer Institute, Shanghai, 200032 China
| | - Xiaowu Xu
- 1Department of Pancreatic Surgery, Fudan University Shanghai Cancer Center, Shanghai, 200032 China.,2Department of Oncology, Shanghai Medical College, Fudan University, Shanghai, 200032 China.,3Pancreatic Cancer Institute, Fudan University, Shanghai, 200032 China.,4Shanghai Pancreatic Cancer Institute, Shanghai, 200032 China
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HNF4A Regulates the Formation of Hepatic Progenitor Cells from Human iPSC-Derived Endoderm by Facilitating Efficient Recruitment of RNA Pol II. Genes (Basel) 2018; 10:genes10010021. [PMID: 30597922 PMCID: PMC6356828 DOI: 10.3390/genes10010021] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2018] [Revised: 12/07/2018] [Accepted: 12/18/2018] [Indexed: 12/13/2022] Open
Abstract
Elucidating the molecular basis of cell differentiation will advance our understanding of organ development and disease. We have previously established a protocol that efficiently produces cells with hepatocyte characteristics from human induced pluripotent stem cells. We previously used this cell differentiation model to identify the transcription factor hepatocyte nuclear factor 4 α (HNF4A) as being essential during the transition of the endoderm to a hepatic fate. Here, we sought to define the molecular mechanisms through which HNF4A controls this process. By combining HNF4A chromatin immunoprecipitation (ChIP) followed by high-throughput DNA sequencing (ChIP-seq) analyses at the onset of hepatic progenitor cell formation with transcriptome data collected during early stages of differentiation, we identified genes whose expression is directly dependent upon HNF4A. By examining the dynamic changes that occur at the promoters of these HNF4A targets we reveal that HNF4A is essential for recruitment of RNA polymerase (RNA pol) II to genes that are characteristically expressed as the hepatic progenitors differentiate from the endoderm.
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14
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Qu M, Duffy T, Hirota T, Kay SA. Nuclear receptor HNF4A transrepresses CLOCK:BMAL1 and modulates tissue-specific circadian networks. Proc Natl Acad Sci U S A 2018; 115:E12305-E12312. [PMID: 30530698 PMCID: PMC6310821 DOI: 10.1073/pnas.1816411115] [Citation(s) in RCA: 54] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Either expression level or transcriptional activity of various nuclear receptors (NRs) have been demonstrated to be under circadian control. With a few exceptions, little is known about the roles of NRs as direct regulators of the circadian circuitry. Here we show that the nuclear receptor HNF4A strongly transrepresses the transcriptional activity of the CLOCK:BMAL1 heterodimer. We define a central role for HNF4A in maintaining cell-autonomous circadian oscillations in a tissue-specific manner in liver and colon cells. Not only transcript level but also genome-wide chromosome binding of HNF4A is rhythmically regulated in the mouse liver. ChIP-seq analyses revealed cooccupancy of HNF4A and CLOCK:BMAL1 at a wide array of metabolic genes involved in lipid, glucose, and amino acid homeostasis. Taken together, we establish that HNF4A defines a feedback loop in tissue-specific mammalian oscillators and demonstrate its recruitment in the circadian regulation of metabolic pathways.
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Affiliation(s)
- Meng Qu
- Keck School of Medicine, University of Southern California, Los Angeles, CA 90089
| | - Tomas Duffy
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA 92037
| | - Tsuyoshi Hirota
- Institute of Transformative Bio-Molecules, Nagoya University, 464-8602 Nagoya, Japan
| | - Steve A Kay
- Keck School of Medicine, University of Southern California, Los Angeles, CA 90089;
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15
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Cottone E, Orso F, Biglia N, Sismondi P, De Bortoli M. Role of Coactivators and Corepressors in Steroid and Nuclear Receptor Signaling: Potential Markers of Tumor Growth and Drug Sensitivity. Int J Biol Markers 2018; 16:151-66. [PMID: 11605727 DOI: 10.1177/172460080101600301] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Nuclear receptors regulate target gene expression in response to steroid and thyroid hormones, retinoids, vitamin D and other ligands. These ligand-dependent transcription factors function by contacting various nuclear cooperating proteins, called coactivators and corepressors, which mediate local chromatin remodeling as well as communication with the basal transcriptional apparatus. Nuclear receptors and their coregulatory proteins play a role in cancer and other diseases, one leading example being the estrogen receptor pathway in breast cancer. Coregulators are often present in limiting amounts in cell nuclei and modifications of their level of expression and/or structure lead to alterations in nuclear receptor functioning, which may be as pronounced as a complete inversion of signaling, i.e. from stimulating to repressing certain genes in response to an identical stimulus. In addition, hemizygous knock-out of certain coactivator genes has been demonstrated to produce cancer-prone phenotypes in mice. Thus, assessment of coactivator and corepressor expression and structure in tumors may turn out to be essential to determine the role of nuclear receptors in cancer and to predict prognosis and response to therapy.
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Affiliation(s)
- E Cottone
- Department of Animal and Human Biology, University of Turin, Italy
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16
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Ranjan A, Ansari SA. Therapeutic potential of Mediator complex subunits in metabolic diseases. Biochimie 2017; 144:41-49. [PMID: 29061530 DOI: 10.1016/j.biochi.2017.10.012] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2017] [Accepted: 10/16/2017] [Indexed: 01/16/2023]
Abstract
The multisubunit Mediator is an evolutionary conserved transcriptional coregulatory complex in eukaryotes. It is needed for the transcriptional regulation of gene expression in general as well as in a gene specific manner. Mediator complex subunits interact with different transcription factors as well as components of RNA Pol II transcription initiation complex and in doing so act as a bridge between gene specific transcription factors and general Pol II transcription machinery. Specific interaction of various Mediator subunits with nuclear receptors (NRs) and other transcription factors involved in metabolism has been reported in different studies. Evidences indicate that ligand-activated NRs recruit Mediator complex for RNA Pol II-dependent gene transcription. These NRs have been explored as therapeutic targets in different metabolic diseases; however, they show side-effects as targets due to their overlapping involvement in different signaling pathways. Here we discuss the interaction of various Mediator subunits with transcription factors involved in metabolism and whether specific interaction of these transcription factors with Mediator subunits could be potentially utilized as therapeutic strategy in a variety of metabolic diseases.
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Affiliation(s)
- Amol Ranjan
- Stowers Institute for Medical Research, 1000 E, 50th Street, Kansas City, MO, 64110, USA
| | - Suraiya A Ansari
- Department of Biochemistry, College of Medicine and Health Sciences, UAE University, AlAin, Abu Dhabi, United Arab Emirates.
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17
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Crosstalk of HNF4 α with extracellular and intracellular signaling pathways in the regulation of hepatic metabolism of drugs and lipids. Acta Pharm Sin B 2016; 6:393-408. [PMID: 27709008 PMCID: PMC5045537 DOI: 10.1016/j.apsb.2016.07.003] [Citation(s) in RCA: 61] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2016] [Revised: 05/05/2016] [Accepted: 05/11/2016] [Indexed: 12/15/2022] Open
Abstract
The liver is essential for survival due to its critical role in the regulation of metabolic homeostasis. Metabolism of xenobiotics, such as environmental chemicals and drugs by the liver protects us from toxic effects of these xenobiotics, whereas metabolism of cholesterol, bile acids (BAs), lipids, and glucose provide key building blocks and nutrients to promote the growth or maintain the survival of the organism. As a well-established master regulator of liver development and function, hepatocyte nuclear factor 4 alpha (HNF4α) plays a critical role in regulating a large number of key genes essential for the metabolism of xenobiotics, metabolic wastes, and nutrients. The expression and activity of HNF4α is regulated by diverse hormonal and signaling pathways such as growth hormone, glucocorticoids, thyroid hormone, insulin, transforming growth factor-β, estrogen, and cytokines. HNF4α appears to play a central role in orchestrating the transduction of extracellular hormonal signaling and intracellular stress/nutritional signaling onto transcriptional changes in the liver. There have been a few reviews on the regulation of drug metabolism, lipid metabolism, cell proliferation, and inflammation by HNF4α. However, the knowledge on how the expression and transcriptional activity of HNF4α is modulated remains scattered. Herein I provide comprehensive review on the regulation of expression and transcriptional activity of HNF4α, and how HNF4α crosstalks with diverse extracellular and intracellular signaling pathways to regulate genes essential in liver pathophysiology.
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18
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Olivares AM, Moreno-Ramos OA, Haider NB. Role of Nuclear Receptors in Central Nervous System Development and Associated Diseases. J Exp Neurosci 2016; 9:93-121. [PMID: 27168725 PMCID: PMC4859451 DOI: 10.4137/jen.s25480] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2015] [Revised: 01/06/2016] [Accepted: 01/07/2016] [Indexed: 11/13/2022] Open
Abstract
The nuclear hormone receptor (NHR) superfamily is composed of a wide range of receptors involved in a myriad of important biological processes, including development, growth, metabolism, and maintenance. Regulation of such wide variety of functions requires a complex system of gene regulation that includes interaction with transcription factors, chromatin-modifying complex, and the proper recognition of ligands. NHRs are able to coordinate the expression of genes in numerous pathways simultaneously. This review focuses on the role of nuclear receptors in the central nervous system and, in particular, their role in regulating the proper development and function of the brain and the eye. In addition, the review highlights the impact of mutations in NHRs on a spectrum of human diseases from autism to retinal degeneration.
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Affiliation(s)
- Ana Maria Olivares
- Department of Ophthalmology, Schepens Eye Research Institute, Massachusetts Eye and Ear, Harvard Medical School, Boston, MA, USA
| | - Oscar Andrés Moreno-Ramos
- Departamento de Ciencias Biológicas, Facultad de Ciencias, Universidad de los Andes, Bogotá, Colombia
| | - Neena B Haider
- Department of Ophthalmology, Schepens Eye Research Institute, Massachusetts Eye and Ear, Harvard Medical School, Boston, MA, USA
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19
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Hyrsova L, Smutny T, Carazo A, Moravcik S, Mandikova J, Trejtnar F, Gerbal-Chaloin S, Pavek P. The pregnane X receptor down-regulates organic cation transporter 1 (SLC22A1) in human hepatocytes by competing for ("squelching") SRC-1 coactivator. Br J Pharmacol 2016; 173:1703-15. [PMID: 26920453 DOI: 10.1111/bph.13472] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2015] [Revised: 01/29/2016] [Accepted: 02/01/2016] [Indexed: 12/17/2022] Open
Abstract
BACKGROUND AND PURPOSE The organic cation transporter 1 (OCT1) transports cationic drugs into hepatocytes. The high hepatic expression of OCT1 is controlled by the HNF4α and USF transcription factors. Pregnane X receptor (PXR) mediates induction of the principal xenobiotic metabolizing enzymes and transporters in the liver. Here, we have assessed the down-regulation of OCT1 expression by PXR activation. EXPERIMENTAL APPROACH We used primary human hepatocytes and related cell lines to measure OCT1 expression and activity, by assaying MPP(+) accumulation. Western blotting, qRT-PCR, the OCT1 promoter gene reporter constructs and chromatin immunoprecipitation assays were also used. KEY RESULTS OCT1 mRNA in human hepatocytes was down-regulated along with reduced [(3) H]MPP(+) accumulation in differentiated HepaRG cells after treatment with rifampicin. Rifampicin and hyperforin as well as the constitutively active PXR mutant T248D suppressed activity of the 1.8 kb OCT1 promoter construct in gene reporter assays. Silencing of both PXR and HNF4α in HepaRG cells blocked the PXR ligand-mediated down-regulation of OCT1 expression. The mutation of HNF4α and USF1 (E-box) responsive elements reversed the PXR-mediated inhibition in gene reporter assays. Chromatin immunoprecipitation assays indicated that PXR activation sequestrates the SRC-1 coactivator from the HNF4α response element and E-box of the OCT1 promoter. Consistent with these findings, exogenous overexpression of the SRC-1, but not the PGC1α coactivator, relieved the PXR-mediated repression of OCT1 transactivation. CONCLUSIONS AND IMPLICATIONS PXR ligands reduced the HNF4α-mediated and USF-mediated transactivation of OCT1 gene expression by competing for SRC-1 and decreased delivery of a model OCT1 substrate into hepatocytes.
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Affiliation(s)
- Lucie Hyrsova
- Department of Pharmacology and Toxicology, Faculty of Pharmacy in Hradec Kralove, Charles University in Prague, Hradec Kralove, Czech Republic
| | - Tomas Smutny
- Department of Pharmacology and Toxicology, Faculty of Pharmacy in Hradec Kralove, Charles University in Prague, Hradec Kralove, Czech Republic
| | - Alejandro Carazo
- Department of Pharmacology and Toxicology, Faculty of Pharmacy in Hradec Kralove, Charles University in Prague, Hradec Kralove, Czech Republic
| | - Stefan Moravcik
- Department of Pharmacology and Toxicology, Faculty of Pharmacy in Hradec Kralove, Charles University in Prague, Hradec Kralove, Czech Republic
| | - Jana Mandikova
- Department of Pharmacology and Toxicology, Faculty of Pharmacy in Hradec Kralove, Charles University in Prague, Hradec Kralove, Czech Republic
| | - Frantisek Trejtnar
- Department of Pharmacology and Toxicology, Faculty of Pharmacy in Hradec Kralove, Charles University in Prague, Hradec Kralove, Czech Republic
| | - Sabine Gerbal-Chaloin
- INSERM, U1183, Institute for Regenerative Medicine and Biotherapy, Montpellier, France.,Université de Montpellier, Montpellier, France
| | - Petr Pavek
- Department of Pharmacology and Toxicology, Faculty of Pharmacy in Hradec Kralove, Charles University in Prague, Hradec Kralove, Czech Republic
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20
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Zheng MW, Zhang CH, Chen K, Huang M, Li YP, Lin WT, Zhang RJ, Zhong L, Xiang R, Li LL, Liu XY, Wei YQ, Yang SY. Preclinical Evaluation of a Novel Orally Available SRC/Raf/VEGFR2 Inhibitor, SKLB646, in the Treatment of Triple-Negative Breast Cancer. Mol Cancer Ther 2015; 15:366-78. [PMID: 26721945 DOI: 10.1158/1535-7163.mct-15-0501] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2015] [Accepted: 11/20/2015] [Indexed: 11/16/2022]
Affiliation(s)
- Ming-Wu Zheng
- State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, Sichuan University, Chengdu, Sichuan, China. Collaborative Innovation Center for Biotherapy, Chengdu, Sichuan, China
| | - Chun-Hui Zhang
- State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, Sichuan University, Chengdu, Sichuan, China. Collaborative Innovation Center for Biotherapy, Chengdu, Sichuan, China
| | - Kai Chen
- State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, Sichuan University, Chengdu, Sichuan, China. Collaborative Innovation Center for Biotherapy, Chengdu, Sichuan, China
| | - Mei Huang
- Key Laboratory of Drug Targeting and Drug Delivery System of Ministry of Education, West China School of Pharmacy, Sichuan University, Chengdu, Sichuan, China
| | - Ya-Ping Li
- State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, Sichuan University, Chengdu, Sichuan, China. Collaborative Innovation Center for Biotherapy, Chengdu, Sichuan, China
| | - Wan-Ting Lin
- State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, Sichuan University, Chengdu, Sichuan, China. Collaborative Innovation Center for Biotherapy, Chengdu, Sichuan, China
| | - Rong-Jie Zhang
- State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, Sichuan University, Chengdu, Sichuan, China. Collaborative Innovation Center for Biotherapy, Chengdu, Sichuan, China
| | - Lei Zhong
- State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, Sichuan University, Chengdu, Sichuan, China. Collaborative Innovation Center for Biotherapy, Chengdu, Sichuan, China
| | - Rong Xiang
- Department of Clinical Medicine, School of Medicine, Nankai University, Tianjin, China
| | - Lin-Li Li
- Key Laboratory of Drug Targeting and Drug Delivery System of Ministry of Education, West China School of Pharmacy, Sichuan University, Chengdu, Sichuan, China
| | - Xin-Yu Liu
- State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, Sichuan University, Chengdu, Sichuan, China. Collaborative Innovation Center for Biotherapy, Chengdu, Sichuan, China
| | - Yu-Quan Wei
- State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, Sichuan University, Chengdu, Sichuan, China. Collaborative Innovation Center for Biotherapy, Chengdu, Sichuan, China
| | - Sheng-Yong Yang
- State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, Sichuan University, Chengdu, Sichuan, China. Collaborative Innovation Center for Biotherapy, Chengdu, Sichuan, China.
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21
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Berasain C, Avila MA. Regulation of hepatocyte identity and quiescence. Cell Mol Life Sci 2015; 72:3831-51. [PMID: 26089250 PMCID: PMC11114060 DOI: 10.1007/s00018-015-1970-7] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2015] [Revised: 05/23/2015] [Accepted: 06/12/2015] [Indexed: 12/11/2022]
Abstract
The liver is a highly differentiated organ with a central role in metabolism, detoxification and systemic homeostasis. To perform its multiple tasks, liver parenchymal cells, the hepatocytes, express a large complement of enabling genes defining their complex phenotype. This phenotype is progressively acquired during fetal development and needs to be maintained in adulthood to guarantee the individual's survival. Upon injury or loss of functional mass, the liver displays an extraordinary regenerative response, mainly based on the proliferation of hepatocytes which otherwise are long-lived quiescent cells. Increasing observations suggest that loss of hepatocellular differentiation and quiescence underlie liver malfunction in chronic liver disease and pave the way for hepatocellular carcinoma development. Here, we briefly review the essential mechanisms leading to the acquisition of liver maturity. We also identify the key molecular factors involved in the preservation of hepatocellular homeostasis and finally discuss potential strategies to preserve liver identity and function.
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Affiliation(s)
- Carmen Berasain
- Division of Hepatology, CIMA, University of Navarra, CIBEREHD, Instituto de Investigación Sanitaria de Navarra (IdiSNA), Avda. Pio XII, n55, 31008, Pamplona, Spain.
| | - Matías A Avila
- Division of Hepatology, CIMA, University of Navarra, CIBEREHD, Instituto de Investigación Sanitaria de Navarra (IdiSNA), Avda. Pio XII, n55, 31008, Pamplona, Spain.
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22
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Affiliation(s)
- Daryl K Granner
- From the Fraternal Order of Eagles Diabetes Research Center, Carver College of Medicine, University of Iowa, Iowa City, Iowa 52242
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23
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Alotaibi H, Basilicata MF, Shehwana H, Kosowan T, Schreck I, Braeutigam C, Konu O, Brabletz T, Stemmler MP. Enhancer cooperativity as a novel mechanism underlying the transcriptional regulation of E-cadherin during mesenchymal to epithelial transition. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2015; 1849:731-42. [DOI: 10.1016/j.bbagrm.2015.01.005] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/13/2014] [Revised: 01/06/2015] [Accepted: 01/24/2015] [Indexed: 01/28/2023]
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Abstract
Hepatocyte nuclear factor 4α (HNF4α) is an orphan nuclear receptor commonly known as the master regulator of hepatic differentiation, owing to the large number of hepatocyte-specific genes it regulates. Whereas the role of HNF4α in hepatocyte differentiation is well recognized and extensively studied, its role in regulation of cell proliferation is relatively less known. Recent studies have revealed that HNF4α inhibits proliferation not only of hepatocytes but also cells in colon and kidney. Further, a growing number of studies have demonstrated that inhibition or loss of HNF4α promotes tumorigenesis in the liver and colon, and reexpression of HNF4α results in decreased cancer growth. Studies using tissue-specific conditional knockout mice, knock-in studies, and combinatorial bioinformatics of RNA/ChIP-sequencing data indicate that the mechanisms of HNF4α-mediated inhibition of cell proliferation are multifold, involving epigenetic repression of promitogenic genes, significant cross talk with other cell cycle regulators including c-Myc and cyclin D1, and regulation of miRNAs. Furthermore, studies indicate that posttranslational modifications of HNF4α may change its activity and may be at the core of its dual role as a differentiation factor and repressor of proliferation. This review summarizes recent findings on the role of HNF4α in cell proliferation and highlights the newly understood function of this old receptor.
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Affiliation(s)
- Chad Walesky
- *Department of Pharmacology, Toxicology and Therapeutics, University of Kansas Medical Center, Kansas City, KS, USA
- †Department of Medicine – Genetics Division, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA, USA
| | - Udayan Apte
- *Department of Pharmacology, Toxicology and Therapeutics, University of Kansas Medical Center, Kansas City, KS, USA
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25
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Regulatory Actions of Glucocorticoid Hormones: From Organisms to Mechanisms. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2015. [DOI: 10.1007/978-1-4939-2895-8_1] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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26
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Tints K, Prink M, Neuman T, Palm K. LXXLL peptide converts transportan 10 to a potent inducer of apoptosis in breast cancer cells. Int J Mol Sci 2014; 15:5680-98. [PMID: 24705462 PMCID: PMC4013589 DOI: 10.3390/ijms15045680] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2014] [Revised: 03/18/2014] [Accepted: 03/24/2014] [Indexed: 12/15/2022] Open
Abstract
Degenerate expression of transcription coregulator proteins is observed in most human cancers. Therefore, in targeted anti-cancer therapy development, intervention at the level of cancer-specific transcription is of high interest. The steroid receptor coactivator-1 (SRC-1) is highly expressed in breast, endometrial, and prostate cancer. It is present in various transcription complexes, including those containing nuclear hormone receptors. We examined the effects of a peptide that contains the LXXLL-motif of the human SRC-1 nuclear receptor box 1 linked to the cell-penetrating transportan 10 (TP10), hereafter referred to as TP10-SRC1LXXLL, on proliferation and estrogen-mediated transcription of breast cancer cells in vitro. Our data show that TP10-SRC1LXXLL induced dose-dependent cell death of breast cancer cells, and that this effect was not affected by estrogen receptor (ER) status. Surprisingly TP10-SRC1LXXLL severely reduced the viability and proliferation of hormone-unresponsive breast cancer MDA-MB-231 cells. In addition, the regulation of the endogenous ERα direct target gene pS2 was not affected by TP10-SRC1LXXLL in estrogen-stimulated MCF-7 cells. Dermal fibroblasts were similarly affected by treatment with higher concentrations of TP10-SRC1LXXLL and this effect was significantly delayed. These results suggest that the TP10-SRC1LXXLL peptide may be an effective drug candidate in the treatment of cancers with minimal therapeutic options, for example ER-negative tumors.
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Affiliation(s)
- Kairit Tints
- Protobios LLC, Mäealuse 4, Tallinn 12618, Estonia.
| | - Madis Prink
- Protobios LLC, Mäealuse 4, Tallinn 12618, Estonia.
| | | | - Kaia Palm
- Protobios LLC, Mäealuse 4, Tallinn 12618, Estonia.
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27
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Wang Z, Burke PA. The role of microRNAs in hepatocyte nuclear factor-4alpha expression and transactivation. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2013; 1829:436-42. [PMID: 23298640 DOI: 10.1016/j.bbagrm.2012.12.009] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/12/2012] [Revised: 12/14/2012] [Accepted: 12/26/2012] [Indexed: 12/21/2022]
Abstract
Hepatocyte nuclear factor (HNF)-4α is a key member of the transcription factor network regulating hepatocyte differentiation and function. Genetic and molecular evidence suggests that expression of HNF-4α is mainly regulated at the transcriptional level. Activation of HNF-4A gene involves the interaction of distinct sets of transcription factors and co-transcription factors within enhancer and promoter regions. Here we study the inhibitory effect of microRNAs (miRNAs) on the 3'-untranslated region (3'-UTR) of HNF-4A mRNA. The potential recognition elements of a set of miRNAs were identified utilizing bioinformatics analysis. The family members of miR-34 and miR-449, including miR-34a, miR-34c-5p and miR-449a, share the same target elements located at two distinct locations within the 3'-UTR of HNF-4A. The over-expression of miR-34a, miR-34c-5p or miR-449a in HepG2 cells led to a significant decrease in the activity of luciferase reporter carrying 3'-UTR of HNF-4A. The repressive effect on reporter activity was partially or fully eliminated when one or two of the binding site(s) for miR-34a/miR-34c-5p/miR-449a were deleted within the 3'-UTR. The protein level of HNF-4α was dramatically reduced by over-expression of miR-34a, miR-34c-5p and miR-449a, which correlates with a decrease in the binding activity of HNF-4α and transactivation of HNF-4α target genes. These results suggest that the recognition sites of miR-34a, miR-34c-5p and miR-449a within 3'-UTR of HNF-4A are functional. The mechanism of down-regulation of the binding activity and transactivation of HNF-4α by the miRNAs involves the decrease in HNF-4α protein level via miRNAs selectively targeting HNF-4A 3'-UTR, leading to the translational repression of HNF-4α expression.
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Affiliation(s)
- Zhongyan Wang
- Department of Surgery, Boston University School of Medicine, Boston, MA 02118, USA
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28
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Fraczek J, Bolleyn J, Vanhaecke T, Rogiers V, Vinken M. Primary hepatocyte cultures for pharmaco-toxicological studies: at the busy crossroad of various anti-dedifferentiation strategies. Arch Toxicol 2012; 87:577-610. [PMID: 23242478 DOI: 10.1007/s00204-012-0983-3] [Citation(s) in RCA: 88] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2012] [Accepted: 11/19/2012] [Indexed: 01/24/2023]
Abstract
Continuously increasing understanding of the molecular triggers responsible for the onset of diseases, paralleled by an equally dynamic evolution of chemical synthesis and screening methods, offers an abundance of pharmacological agents with a potential to become new successful drugs. However, before patients can benefit of newly developed pharmaceuticals, stringent safety filters need to be applied to weed out unfavourable drug candidates. Cost effectiveness and the need to identify compound liabilities, without exposing humans to unnecessary risks, has stimulated the shift of the safety studies to the earliest stages of drug discovery and development. In this regard, in vivo relevant organotypic in vitro models have high potential to revolutionize the preclinical safety testing. They can enable automation of the process, to match the requirements of high-throughput screening approaches, while satisfying ethical considerations. Cultures of primary hepatocytes became already an inherent part of the preclinical pharmaco-toxicological testing battery, yet their routine use, particularly for long-term assays, is limited by the progressive deterioration of liver-specific features. The availability of suitable hepatic and other organ-specific in vitro models is, however, of paramount importance in the light of changing European legal regulations in the field of chemical compounds of different origin, which gradually restrict the use of animal studies for safety assessment, as currently witnessed in cosmetic industry. Fortunately, research groups worldwide spare no effort to establish hepatic in vitro systems. In the present review, both classical and innovative methodologies to stabilize the in vivo-like hepatocyte phenotype in culture of primary hepatocytes are presented and discussed.
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Affiliation(s)
- J Fraczek
- Department of Toxicology, Faculty of Medicine and Pharmacy, Centre for Pharmaceutical Research, Vrije Universiteit Brussel, Belgium.
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Han EH, Rha GB, Chi YI. MED25 is a mediator component of HNF4α-driven transcription leading to insulin secretion in pancreatic beta-cells. PLoS One 2012; 7:e44007. [PMID: 22952853 PMCID: PMC3431373 DOI: 10.1371/journal.pone.0044007] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2012] [Accepted: 07/27/2012] [Indexed: 11/19/2022] Open
Abstract
Unique nuclear receptor Hepatocyte Nuclear Factor 4α (HNF4α) is an essential transcriptional regulator for early development and proper function of pancreatic ß-cells, and its mutations are monogenic causes of a dominant inherited form of diabetes referred to as Maturity Onset Diabetes of the Young 1 (MODY1). As a gene-specific transcription factor, HNF4α exerts its function through various molecular interactions, but its protein recruiting network has not been fully characterized. Here we report the identification of MED25 as one of the HNF4α binding partners in pancreatic ß-cells leading to insulin secretion which is impaired in MODY patients. MED25 is one of the subunits of the Mediator complex that is required for induction of RNA polymerase II transcription by various transcription factors including nuclear receptors. This HNF4α-MED25 interaction was initially identified by a yeast-two-hybrid method, confirmed by in vivo and in vitro analyses, and proven to be mediated through the MED25-LXXLL motif in a ligand-independent manner. Reporter-gene based transcription assays and siRNA/shRNA-based gene silencing approaches revealed that this interaction is crucial for full activation of HNF4α-mediated transcription, especially expression of target genes implicated in glucose-stimulated insulin secretion. Selected MODY mutations at the LXXLL motif binding pocket disrupt these interactions and cause impaired insulin secretion through a 'loss-of-function' mechanism.
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Affiliation(s)
- Eun Hee Han
- Section of Structural Biology, Hormel Institute, University of Minnesota, Austin, Minnesota, United States of America
| | - Geun Bae Rha
- Section of Structural Biology, Hormel Institute, University of Minnesota, Austin, Minnesota, United States of America
| | - Young-In Chi
- Section of Structural Biology, Hormel Institute, University of Minnesota, Austin, Minnesota, United States of America
- * E-mail:
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Walsh CA, Qin L, Tien JCY, Young LS, Xu J. The function of steroid receptor coactivator-1 in normal tissues and cancer. Int J Biol Sci 2012; 8:470-85. [PMID: 22419892 PMCID: PMC3303173 DOI: 10.7150/ijbs.4125] [Citation(s) in RCA: 76] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2012] [Accepted: 02/20/2012] [Indexed: 11/05/2022] Open
Abstract
In 1995, the steroid receptor coactivator-1 (SRC-1) was identified as the first authentic steroid receptor coactivator. Since then, the SRC proteins have remained at the epicenter of coregulator biology, molecular endocrinology and endocrine-related cancer. Cumulative works on SRC-1 have shown that it is primarily a nuclear receptor coregulator and functions to construct highly specific enzymatic protein complexes which can execute efficient and successful transcriptional activation of designated target genes. The versatile nature of SRC-1 enables it to respond to steroid dependent and steroid independent stimulation, allowing it to bind across many families of transcription factors to orchestrate and regulate complex physiological reactions. This review highlights the multiple functions of SRC-1 in the development and maintenance of normal tissue functions as well as its major role in mediating hormone receptor responsiveness. Insights from genetically manipulated mouse models and clinical data suggest SRC-1 is significantly overexpressed in many cancers, in particular, cancers of the reproductive tissues. SRC-1 has been associated with cellular proliferation and tumor growth but its major tumorigenic contributions are promotion and execution of breast cancer metastasis and mediation of resistance to endocrine therapies. The ability of SRC-1 to coordinate multiple signaling pathways makes it an important player in tumor cells' escape of targeted therapy.
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Affiliation(s)
- Claire A Walsh
- Endocrine Oncology Research Group, Royal College of Surgeons in Ireland, Dublin, Ireland
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Takezawa T, Matsunaga T, Aikawa K, Nakamura K, Ohmori S. Lower Expression of HNF4α and PGC1α Might Impair Rifampicin-mediated CYP3A4 Induction under Conditions Where PXR Is Overexpressed in Human Fetal Liver Cells. Drug Metab Pharmacokinet 2012; 27:430-8. [DOI: 10.2133/dmpk.dmpk-11-rg-126] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Taubert S, Ward JD, Yamamoto KR. Nuclear hormone receptors in nematodes: evolution and function. Mol Cell Endocrinol 2011; 334:49-55. [PMID: 20438802 PMCID: PMC3042524 DOI: 10.1016/j.mce.2010.04.021] [Citation(s) in RCA: 72] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/07/2010] [Revised: 04/18/2010] [Accepted: 04/24/2010] [Indexed: 11/16/2022]
Abstract
Nuclear hormone receptors (NHRs) are proteins that regulate gene expression in response to developmental, environmental, and nutritional signals. The activity of some NHRs is selectively and reversibly modulated by small molecular weight compounds. However, for others - termed "orphan" receptors - no such ligands have (yet) been identified, and at least some NHRs may lack natural ligands. NHRs exhibit a stereotyped architecture, with conserved N-terminal DNA-binding domains (DBDs) and more variable C-terminal ligand-binding domains (LBDs). NHRs control the transcription of remarkably diverse and specific gene networks, apparently by integrating multiple regulatory inputs that interact with distinct receptor surfaces; these inputs include small molecule ligands, transcriptional coregulators, and response elements, the genomic sites to which the receptors bind. NHRs comprise an ancient superfamily found in all metazoans, and recent findings have revealed NHR-like regulatory factors in fungi. Here, we consider NHR function and evolution in nematodes, roundworms that inhabit terrestrial, marine, and freshwater habitats; we focus in particular on the well-established experimental organism Caenorhabditis elegans. Interestingly, the C. elegans genome encodes a massively expanded NHR family; we speculate that some of the multiple physiological activities governed by individual mammalian NHRs may be distributed among multiple members of the C. elegans family, potentially focusing and simplifying functional analyses. Accordingly, investigations of relevant NHR cofactors, ligands, and response elements might also prove to be simpler; moreover, the abbreviated intergenic regions of the C. elegans genome will facilitate the assignment of response elements to target genes. Finally, the growing interest in medically relevant nematodes is providing novel insights into the function and evolution of NHRs.
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Affiliation(s)
- Stefan Taubert
- Department of Medical Genetics, University of British Columbia; Centre for Molecular Medicine and Therapeutics; and Child & Family Research Institute, Vancouver, BC, Canada
| | - Jordan D. Ward
- Department of Cellular and Molecular Pharmacology, University of California San Francisco, San Francisco, CA, USA
| | - Keith R. Yamamoto
- Department of Cellular and Molecular Pharmacology, University of California San Francisco, San Francisco, CA, USA
- Corresponding author: UCSF, 600 16 St, GH-S574, San Francisco CA 94143-2280; Phone: +1 (415) 476-8445;
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Med25 is required for RNA polymerase II recruitment to specific promoters, thus regulating xenobiotic and lipid metabolism in human liver. Mol Cell Biol 2010; 31:466-81. [PMID: 21135126 DOI: 10.1128/mcb.00847-10] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
Hepatocyte nuclear factor 4α (HNF4α) controls the expression of many critical metabolic pathways, and the Mediator complex occupies a central role in recruiting RNA polymerase II (Pol II) to these gene promoters. An impaired transcriptional HNF4α network in human liver is responsible for many pathological conditions, such as altered drug metabolism, fatty liver, and diabetes. Here, we report that Med25, an associated member of the Mediator complex, is required for the association of HNF4α with Mediator, its several cofactors, and RNA Pol II. Further, increases and decreases in endogenous Med25 levels are reflected in the composition of the transcriptional complex, Pol II recruitment, and the expression of HNF4α-bound target genes. A novel feature of Med25 is that it imparts "selectivity." Med25 affects only a significant subset of HNF4α target genes that selectively regulate drug and lipid metabolism. These results define a role for Med25 and the Mediator complex in the regulation of xenobiotic metabolism and lipid homeostasis.
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Inoue SI, Yoshinari K, Sugawara M, Yamazoe Y. Activated Sterol Regulatory Element-Binding Protein-2 Suppresses Hepatocyte Nuclear Factor-4-Mediated Cyp3a11 Expression in Mouse Liver. Mol Pharmacol 2010; 79:148-56. [DOI: 10.1124/mol.110.068577] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
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Ungaro P, Teperino R, Mirra P, Longo M, Ciccarelli M, Raciti GA, Nigro C, Miele C, Formisano P, Beguinot F. Hepatocyte nuclear factor (HNF)-4alpha-driven epigenetic silencing of the human PED gene. Diabetologia 2010; 53:1482-92. [PMID: 20396999 DOI: 10.1007/s00125-010-1732-x] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/01/2010] [Accepted: 02/25/2010] [Indexed: 01/03/2023]
Abstract
AIMS/HYPOTHESIS Overexpression of PED (also known as PEA15) determines insulin resistance and impaired insulin secretion and may contribute to progression toward type 2 diabetes. Recently, we found that the transcription factor hepatocyte nuclear factor (HNF)-4alpha binds to PED promoter and represses its transcription. However, the molecular details responsible for regulation of PED gene remain unclear. METHODS Here we used gain and loss of function approaches to investigate the hypothesis that HNF-4alpha controls chromatin remodelling at the PED promoter in human cell lines. RESULTS HNF-4alpha production and binding induce chromatin remodelling at the -250 to 50 region of PED, indicating that remodelling is limited to two nucleosomes located at the proximal promoter. Chromatin immunoprecipitation assays also revealed concomitant HNF-4alpha-induced deacetylation of histone H3 at Lys9 and Lys14, and increased dimethylation of histone H3 at Lys9. The latter was followed by reduction of histone H3 Lys4 dimethylation. HNF-4alpha was also shown to target the histone deacetylase complex associated with silencing mediator of retinoic acid and thyroid hormone receptor, both at the PED promoter, and at GRB14 and USP21 regulatory regions, leading to a reduction of mRNA levels. Moreover, HNF-4alpha silencing and PED overexpression were accompanied by a significant reduction of hepatic glycogen content. CONCLUSIONS/INTERPRETATION These results show that HNF-4alpha serves as a scaffold protein for histone deacetylase activities, thereby inhibiting liver expression of genes including PED. Dysregulation of these mechanisms may lead to upregulation of the PED gene in type 2 diabetes.
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Affiliation(s)
- P Ungaro
- Dipartimento di Biologia e Patologia Cellulare e Molecolare L. Califano & Istituto di Endocrinologia ed Oncologia Sperimentale del CNR, Università di Napoli Federico II, Via Sergio Pansini, 5, Naples, 80131, Italy.
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Dankel SN, Hoang T, Flågeng MH, Sagen JV, Mellgren G. cAMP-mediated regulation of HNF-4alpha depends on the level of coactivator PGC-1alpha. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2010; 1803:1013-9. [PMID: 20670916 DOI: 10.1016/j.bbamcr.2010.05.008] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Received: 11/26/2009] [Revised: 05/26/2010] [Accepted: 05/28/2010] [Indexed: 02/09/2023]
Abstract
Hepatocyte nuclear factor-4 alpha (HNF-4alpha) is a member of the nuclear receptor superfamily with important roles in hepatic metabolism. Fasting induces the cAMP/protein kinase A (PKA)-signaling pathway. The mechanisms whereby cAMP regulates HNF-4alpha transcriptional activity are incompletely understood. We have therefore investigated the role of cAMP/PKA in regulation of HNF-4alpha in COS-1 cells and the hepatoma HepG2 cell line. cAMP/PKA inhibited the transcriptional activity of HNF-4alpha in COS-1 cells, whereas a stimulatory effect was observed in HepG2 cells. The cAMP-induced inhibition of HNF-4alpha in COS-1 cells was counteracted by overexpression of the nuclear receptor coactivator PGC-1alpha, and cAMP/PKA-dependent induction of the PGC1A gene in HepG2 cells seems to explain the cell specific differences. This was further supported by knock-down of PGC-1alpha in HepG2 cells, which abolished the stimulatory effect of PKA on HNF-4alpha transcriptional activity. Similar to the cAMP/PKA-mediated regulation of HNF-4alpha, overexpression of the cAMP-response element binding protein (CREB) inhibited the transcriptional activity of HNF-4alpha in COS-1 cells, regardless of cAMP/PKA activation and CREB phosphorylation. Moreover, activation of CREB by cAMP/PKA further stimulated HNF-4alpha transactivation in HepG2 cells. cAMP induced the expression of the HNF-4alpha target genes PCK1 and G6Pase in these cells. In conclusion, our results suggest that the level of PGC-1alpha determines whether the cAMP/PKA-pathway overall stimulates or inhibits HNF-4alpha transcriptional activation.
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Affiliation(s)
- Simon Nitter Dankel
- Institute of Medicine, University of Bergen and the Hormone Laboratory, Haukeland University Hospital, N-5021 Bergen, Norway
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Kim MJ, Lee W, Park EJ, Park SY. Role of hepatocyte nuclear factor-4α in transcriptional regulation of C1qTNF-related protein 5 in the liver. FEBS Lett 2010; 584:3080-4. [DOI: 10.1016/j.febslet.2010.05.049] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2010] [Revised: 05/20/2010] [Accepted: 05/22/2010] [Indexed: 10/19/2022]
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Chiang JYL. Hepatocyte nuclear factor 4alpha regulation of bile acid and drug metabolism. Expert Opin Drug Metab Toxicol 2010; 5:137-47. [PMID: 19239393 DOI: 10.1517/17425250802707342] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The hepatocyte nuclear factor 4alpha (HNF4alpha) is a liver-enriched nuclear receptor that plays a critical role in early morphogenesis, fetal liver development, liver differentiation and metabolism. Human HNF4alpha gene mutations cause maturity on-set diabetes of the young type 1, an autosomal dominant non-insulin-dependent diabetes mellitus. HNF4alpha is an orphan nuclear receptor because of which the endogenous ligand has not been firmly identified. The trans-activating activity of HNF4alpha is enhanced by interacting with co-activators and inhibited by corepressors. Recent studies have revealed that HNF4alpha plays a central role in regulation of bile acid metabolism in the liver. Bile acids are required for biliary excretion of cholesterol and metabolites, and intestinal absorption of fat, nutrients, drug and xenobiotics for transport and distribution to liver and other tissues. Bile acids are signaling molecules that activate nuclear receptors to control lipids and drug metabolism in the liver and intestine. Therefore, HNF4alpha plays a central role in coordinated regulation of bile acid and xenobiotics metabolism. Drugs that specifically activate HNF4alpha could be developed for treating metabolic diseases such as diabetes, dyslipidemia and cholestasis, as well as drug metabolism and detoxification.
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Affiliation(s)
- John Y L Chiang
- Northeastern Ohio Universities Colleges of Medicine and Pharmacy, Department of Integrative Medical Sciences, Rootstown, Ohio 44272, USA.
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Xu J, Wu RC, O’Malley BW. Normal and cancer-related functions of the p160 steroid receptor co-activator (SRC) family. Nat Rev Cancer 2009; 9:615-30. [PMID: 19701241 PMCID: PMC2908510 DOI: 10.1038/nrc2695] [Citation(s) in RCA: 381] [Impact Index Per Article: 25.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The three homologous members of the p160 SRC family (SRC1, SRC2 and SRC3) mediate the transcriptional functions of nuclear receptors and other transcription factors, and are the most studied of all the transcriptional co-activators. Recent work has indicated that the SRCgenes are subject to amplification and overexpression in various human cancers. Some of the molecular mechanisms responsible for SRC overexpression, along with the mechanisms by which SRCs promote breast and prostate cancer cell proliferation and survival, have been identified, as have the specific contributions of individual SRC family members to spontaneous breast and prostate carcinogenesis in genetically manipulated mouse models. These studies have identified new challenges for cancer research and therapy.
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Affiliation(s)
- Jianming Xu
- Department of Molecular and Cellular Biology, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030 USA
- Luzhou Medical College, Luzhou, Sichuan 646000, China
| | - Ray-Chang Wu
- Department of Molecular and Cellular Biology, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030 USA
| | - Bert W. O’Malley
- Department of Molecular and Cellular Biology, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030 USA
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40
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Nedumaran B, Hong S, Xie YB, Kim YH, Seo WY, Lee MW, Lee CH, Koo SH, Choi HS. DAX-1 acts as a novel corepressor of orphan nuclear receptor HNF4alpha and negatively regulates gluconeogenic enzyme gene expression. J Biol Chem 2009; 284:27511-23. [PMID: 19651776 DOI: 10.1074/jbc.m109.034660] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
DAX-1 (dosage-sensitive sex reversal adrenal hypoplasia congenital critical region on X chromosome, gene 1) is an atypical member of the nuclear receptor family and acts as a corepressor of a number of nuclear receptors. HNF4alpha (hepatocyte nuclear factor 4alpha) is a liver-enriched transcription factor that controls the expression of a variety of genes involved in cholesterol, fatty acid, and glucose metabolism. Here we show that DAX-1 inhibits transcriptional activity of HNF4alpha and modulates hepatic gluconeogenic gene expression. Hepatic DAX-1 expression is increased by insulin and SIK1 (salt-inducible kinase 1), whereas it is decreased in high fat diet-fed and diabetic mice. Coimmunoprecipitation assay from mouse liver samples depicts that endogenous DAX-1 interacts with HNF4alpha in vivo. In vivo chromatin immunoprecipitation assay affirms that the recruitment of DAX-1 on the phosphoenolpyruvate carboxykinase (PEPCK) gene promoter is inversely correlated with the recruitment of PGC-1alpha and HNF4alpha under fasting and refeeding, showing that DAX-1 could compete with the coactivator PGC-1alpha for binding to HNF4alpha. Adenovirus-mediated expression of DAX-1 decreased both HNF4alpha- and forskolin-mediated gluconeogenic gene expressions. In addition, knockdown of DAX-1 partially reverses the insulin-mediated inhibition of gluconeogenic gene expression in primary hepatocytes. Finally, DAX-1 inhibits PEPCK and glucose-6-phosphatase gene expression and significantly lowers fasting blood glucose level in high fat diet-fed mice, suggesting that DAX-1 can modulate hepatic gluconeogenesis in vivo. Overall, this study demonstrates that DAX-1 acts as a corepressor of HNF4alpha to negatively regulate hepatic gluconeogenic gene expression in liver.
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Affiliation(s)
- Balachandar Nedumaran
- Hormone Research Center, School of Biological Science and Technology, Chonnam National University, Gwangju 500-757, South Korea
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Snykers S, Henkens T, De Rop E, Vinken M, Fraczek J, De Kock J, De Prins E, Geerts A, Rogiers V, Vanhaecke T. Role of epigenetics in liver-specific gene transcription, hepatocyte differentiation and stem cell reprogrammation. J Hepatol 2009; 51:187-211. [PMID: 19457566 DOI: 10.1016/j.jhep.2009.03.009] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Controlling both growth and differentiation of stem cells and their differentiated somatic progeny is a challenge in numerous fields, from preclinical drug development to clinical therapy. Recently, new insights into the underlying molecular mechanisms have unveiled key regulatory roles of epigenetic marks driving cellular pluripotency, differentiation and self-renewal/proliferation. Indeed, the transcription of genes, governing cell-fate decisions during development and maintenance of a cell's differentiated status in adult life, critically depends on the chromatin accessibility of transcription factors to genomic regulatory and coding regions. In this review, we discuss the epigenetic control of (liver-specific) gene-transcription and the intricate interplay between chromatin modulation, including histone (de)acetylation and DNA (de)methylation, and liver-enriched transcription factors. Special attention is paid to their role in directing hepatic differentiation of primary hepatocytes and stem cells in vitro.
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Affiliation(s)
- Sarah Snykers
- Department of Toxicology, Vrije Universiteit Brussel, Laarbeeklaan 103, 1090 Brussels, Belgium.
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Huang J, Levitsky LL, Rhoads DB. Novel P2 promoter-derived HNF4alpha isoforms with different N-terminus generated by alternate exon insertion. Exp Cell Res 2009; 315:1200-11. [PMID: 19353766 DOI: 10.1016/j.yexcr.2009.01.004] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Hepatocyte nuclear factor 4alpha (HNF4alpha) is a critical transcription factor for pancreas and liver development and functions in islet beta cells to maintain glucose homeostasis. Mutations in the human HNF4A gene lead to maturity onset diabetes of the young (MODY1) and polymorphisms are associated with increased risk for type 2 diabetes mellitus (T2DM). Expression of six HNF4alpha variants, three each from two developmentally regulated promoters, has been firmly established. We have now detected a new set of HNF4alpha variants designated HNF4alpha10-12 expressed from distal promoter P2. These variants, generated by inclusion of previously undetected exon 1E (human=222 nt, rodent=136 nt) following exon 1D have an altered N-terminus but identical remaining reading frame. HNF4alpha10-alpha12 are expressed in pancreatic islets (and liver) and exhibit transactivation potentials similar to the corresponding alpha7-alpha9 isoforms. DNA-binding analyses implied much higher protein levels of HNF4alpha10-alpha12 in liver than expected from the RT-PCR data. Our results provide evidence for a more complex expression pattern of HNF4alpha than previously appreciated. We recommend inclusion of exon 1E and nearby DNA sequences in screening for HNF4alpha mutations and polymorphisms in genetic analyses of MODY1 and T2DM.
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Affiliation(s)
- Jianmin Huang
- MassGeneral Hospital for Children, Harvard Medical School, Boston, Massachusetts 02114-2696, USA.
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Wang HY, Ho PC, Lan CY, Chang MDT. Transcriptional regulation of human eosinophil RNase2 by the liver-enriched hepatocyte nuclear factor 4. J Cell Biochem 2009; 106:317-26. [PMID: 19115260 DOI: 10.1002/jcb.22008] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Human eosinophil-derived neurotoxin (EDN, RNase2) and eosinophil cationic protein (ECP, RNase3) sequences possess as high as 92% identity in their promoter regions. The major difference within this region is a 34-nucleotide (34-nt) segment appeared only in the edn promoter. In addition, six discrete segments existed in the regulatory regions of both edn and ecp. Our previous study indicated that the 34-nt segment is responsive for higher transcription activity of edn in comparison with ecp, via binding to transcription activator Sp1. In this study, the roles of the six discrete segments in transcription regulation were investigated and the -350/-329 region (ednR2) was shown to be involved in the regulation of edn expression. When the ednR2 segment of edn was replaced with that of ecp, a significant decrease in edn promoter activity was detected. Supershift, chromatin immunoprecipitation, and DNA affinity precipitation assays further showed that a transcription factor HNF4 bound to the ednR2 region of edn promoter in vitro. Interestingly, HNF4 overexpression resulted in the reduction of edn promoter activity in HepG2 cells, due to involvement of both ednR2 and the 34-nt regions, and direct interaction between HNF4 and Sp1, which abolishes Sp1 binging to the 34-nt segment. Moreover, when the Sp1 was depleted in the cell, overexpressed HNF4 enhanced edn promoter activity. Our results provide novel mechanisms for HNF4 function as an activator to regulate edn promoter activity, which account for differential transcription regulation of human eosinophil RNases.
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Affiliation(s)
- Hsiu-Yu Wang
- Institute of Molecular and Cellular Biology & Department of Life Science, National Tsing Hua University, No. 101, Sec. 2, Kuang-Fu Rd., Hsinchu, Taiwan 30013, Republic of China
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Modulation of hepatocyte nuclear factor-4alpha function by the peroxisome-proliferator-activated receptor-gamma co-activator-1alpha in the acute-phase response. Biochem J 2009; 415:289-96. [PMID: 18510493 DOI: 10.1042/bj20080355] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
HNF-4alpha (hepatocyte nuclear factor-4alpha) is a key regulator of liver-specific gene expression. To understand the mechanisms governing the regulation of HNF-4alpha function during the APR (acute-phase response), the effects of transcription co-activators, including p300, PGC-1alpha (peroxisome-proliferator-activated receptor-gamma co-activator-1alpha) and SRC (steroid receptor co-activator)-1alpha were investigated in an injury cell model. We have shown previously that the HNF-4alpha-sensitive APR genes ApoB (apolipoprotein B), TTR (transthyretin) and alpha1-AT (alpha1-antitrypsin) were regulated at the DNA binding and transcriptional levels after cytokine stimulation. We now show that co-activators have a differential impact on the transactivation of HNF-4alpha-sensitive genes via HNF-4alpha-binding sites in ApoB, TTR or alpha1-AT promoters. PGC-1alpha strongly enhances the transactivation of ApoB and alpha1-AT and, to a lesser extent, of TTR, whereas SRC-1alpha and p300 only have a weak or no effect on these three genes. More importantly, it was found that PGC-1alpha has a novel role in the modulation of the binding ability of HNF-4alpha in response to cytokine treatment. Using in vitro and in vivo approaches, electrophoretic mobility-shift and chromatin immunoprecipitation assays, we demonstrate that the reduced HNF-4alpha-DNA binding ability induced by cytokines is eliminated by overexpression of PGC-1alpha. Cytokine treatment does not significantly alter the protein levels of HNF-4alpha and PGC-1alpha, but it does reduce the recruitment of PGC-1alpha to HNF-4alpha-binding sites and thereby decreases transcriptional activity. These results establish the importance of PGC-1alpha for HNF-4alpha function and describe a new HNF-4alpha-dependent regulatory mechanism that is involved in the response to injury.
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Guo S, Burnette R, Zhao L, Vanderford NL, Poitout V, Hagman DK, Henderson E, Ozcan S, Wadzinski BE, Stein R. The stability and transactivation potential of the mammalian MafA transcription factor are regulated by serine 65 phosphorylation. J Biol Chem 2008; 284:759-65. [PMID: 19004825 DOI: 10.1074/jbc.m806314200] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The level of the MafA transcription factor is regulated by a variety of effectors of beta cell function, including glucose, fatty acids, and insulin. Here, we show that phosphorylation at Ser(65) of mammalian MafA influences both protein stability and transactivation potential. Replacement of Ser(65) with Glu to mimic phosphorylation produced a protein that was as unstable as the wild type, whereas Asp or Ala mutation blocked degradation. Analysis of MafA chimeric and deletion constructs suggests that protein phosphorylation at Ser(65) alone represents the initial degradation signal, with ubiquitinylation occurring within the C terminus (amino acids 234-359). Although only wild type MafA and S65E were polyubiquitinylated, both S65D and S65E potently stimulated transactivation compared with S65A. Phosphorylation at Ser(14) also enhanced activation, although it had no impact on protein turnover. The mobility of MafA S65A was profoundly affected upon SDS-PAGE, with the S65E and S65D mutants influenced less due to their ability to serve as substrates for glycogen synthase kinase 3, which acts at neighboring N-terminal residues after Ser(65) phosphorylation. Our observations not only illustrate the sensitivity of the cellular transcriptional and degradation machinery to phosphomimetic mutants at Ser(65), but also demonstrate the singular importance of phosphorylation at this amino acid in regulating MafA activity.
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Affiliation(s)
- Shuangli Guo
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, Tennessee 37232, USA
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Schilling MM, Oeser JK, Chandy JK, Flemming BP, Allen SR, O’Brien RM. Sequence variation between the mouse and human glucose-6-phosphatase catalytic subunit gene promoters results in differential activation by peroxisome proliferator activated receptor gamma coactivator-1alpha. Diabetologia 2008; 51:1505-14. [PMID: 18563384 PMCID: PMC2590337 DOI: 10.1007/s00125-008-1050-8] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/17/2008] [Accepted: 04/18/2008] [Indexed: 10/21/2022]
Abstract
AIMS/HYPOTHESIS The glucose-6-phosphatase catalytic subunit (G6PC) plays a key role in hepatic glucose production by catalysing the final step in gluconeogenesis and glycogenolysis. Peroxisome proliferator activated receptor gamma coactivator-1alpha (PGC-1alpha) stimulates mouse G6pc-luciferase fusion gene expression through hepatocyte nuclear factor-4alpha (HNF-4alpha), which binds an element located between -76 and -64 in the promoter. The aim of this study was to compare the regulation of mouse G6pc and human G6PC gene expression by PGC-1alpha. METHODS PGC-1alpha action was analysed by transient transfection and gel retardation assays. RESULTS In H4IIE cells, PGC-1alpha alone failed to stimulate human G6PC-luciferase fusion gene expression even though the sequence of the -76 to -64 HNF-4alpha binding site is perfectly conserved in the human promoter. This difference could be explained, in part, by a 3 bp sequence variation between the mouse and human promoters. Introducing the human sequence into the mouse G6pc promoter reduced PGC-1alpha-stimulated fusion gene expression, whereas the inverse experiment, in which the mouse sequence was introduced into the human G6PC promoter, resulted in the generation of a G6PC-luciferase fusion gene that was now induced by PGC-1alpha. This critical 3 bp region is located immediately adjacent to a consensus nuclear hormone receptor half-site that is perfectly conserved between the mouse G6pc and human G6PC promoters. Gel retardation experiments revealed that this 3 bp region influences the affinity of HNF-4alpha binding to the half-site. CONCLUSIONS/INTERPRETATION These observations suggest that PGC-1alpha may be more important in the control of mouse G6pc than human G6PC gene expression.
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Affiliation(s)
| | | | | | | | | | - Richard M. O’Brien
- To whom correspondence should be addressed: Department of Molecular Physiology and Biophysics, 8415 MRB IV, 2213 Garland Ave, Vanderbilt University Medical School, Nashville, TN 37232-0615, Telephone (615) 936-1503; Facsimile (615) 322-7236, E-mail:
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Harries LW, Locke JM, Shields B, Hanley NA, Hanley KP, Steele A, Njølstad PR, Ellard S, Hattersley AT. The diabetic phenotype in HNF4A mutation carriers is moderated by the expression of HNF4A isoforms from the P1 promoter during fetal development. Diabetes 2008; 57:1745-52. [PMID: 18356407 DOI: 10.2337/db07-1742] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
OBJECTIVE Mutations in the alternatively spliced HNF4A gene cause maturity-onset diabetes of the young (MODY). We characterized the spatial and developmental expression patterns of HNF4A transcripts in human tissues and investigated their role as potential moderators of the MODY phenotype. RESEARCH DESIGN AND METHODS We measured the expression of HNF4A isoforms in human adult tissues and gestationally staged fetal pancreas by isoform-specific real-time PCR. The correlation between mutation position and age of diagnosis or age-related penetrance was assessed in a cohort of 190 patients with HNF4A mutations. RESULTS HNF4A was expressed exclusively from the P2 promoter in adult pancreas, but from 9 weeks until at least 26 weeks after conception, up to 23% of expression in fetal pancreas was of P1 origin. HNF4A4-6 transcripts were not detected in any tissue. In whole pancreas, HNF4A9 expression was greater than in islets isolated from the endocrine pancreas (relative level 22 vs. 7%). Patients with mutations in exons 9 and 10 (absent from HNF4A3, HNF4A6, and HNF4A9 isoforms) developed diabetes later than those with mutations in exons 2-8, where all isoforms were affected (40 vs. 24 years; P = 0.029). Exon 9/10 mutations were also associated with a reduced age-related penetrance (53 vs. 10% without diabetes at age 55 years; P < 0.00001). CONCLUSIONS We conclude that isoforms derived from the HNF4A P1 promoter are expressed in human fetal, but not adult, pancreas, and that their presence during pancreatic development may moderate the diabetic phenotype in individuals with mutations in the HNF4A gene.
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Affiliation(s)
- Lorna W Harries
- Institute of Biomedical and Clinical Sciences, Peninsula Medical School, Exeter, UK.
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48
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Holloway MG, Miles GD, Dombkowski AA, Waxman DJ. Liver-specific hepatocyte nuclear factor-4alpha deficiency: greater impact on gene expression in male than in female mouse liver. Mol Endocrinol 2008; 22:1274-86. [PMID: 18276827 PMCID: PMC2366185 DOI: 10.1210/me.2007-0564] [Citation(s) in RCA: 81] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2007] [Accepted: 02/05/2008] [Indexed: 01/18/2023] Open
Abstract
Hepatocyte nuclear factor (HNF)-4alpha is a liver-enriched transcription factor that regulates numerous liver-expressed genes including several sex-specific cytochrome P450 genes. Presently, a liver-specific HNF4alpha-deficient mouse model was used to characterize the impact of liver HNF4alpha deficiency on a global scale using 41,174 feature microarrays. A total of 4994 HNF4alpha-dependent genes were identified, of which about 1000 fewer genes responded to the loss of HNF4alpha in female liver as compared with male liver. Sex differences in the impact of liver HNF4alpha deficiency were even more dramatic when genes showing sex-specific expression were examined. Thus, 372 of the 646 sex-specific genes characterized by a dependence on HNF4alpha responded to the loss of HNF4alpha in males only, as compared with only 61 genes that responded in females only. Moreover, in male liver, 78% of 508 male-specific genes were down-regulated and 42% of 356 female-specific genes were up-regulated in response to the loss of HNF4alpha, with sex specificity lost for 90% of sex-specific genes. This response to HNF4alpha deficiency is similar to the response of male mice deficient in the GH-activated transcription factor signal transducer and activator of transcription 5b (STAT5b), where 90% of male-specific genes were down-regulated and 61% of female-specific genes were up-regulated, suggesting these two factors cooperatively regulate liver sex specificity by mechanisms that are primarily active in males. Finally, 203 of 648 genes previously shown to bind HNF4alpha near the transcription start site in mouse hepatocytes were affected by HNF4alpha deficiency in mouse liver, with the HNF4alpha-bound gene set showing a 5-fold enrichment for genes positively regulated by HNF4alpha. Thus, a substantial fraction of the HNF4alpha-dependent genes reported here are likely to be direct targets of HNF4alpha.
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Affiliation(s)
- Minita G Holloway
- Division of Cell and Molecular Biology, Department of Biology, Boston University, Boston, Massachusetts 02215, USA
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Schäfer G, Wißmann C, Hertel J, Lunyak V, Höcker M. Regulation of Vascular Endothelial Growth Factor D by Orphan Receptors Hepatocyte Nuclear Factor-4α and Chicken Ovalbumin Upstream Promoter Transcription Factors 1 and 2. Cancer Res 2008; 68:457-66. [DOI: 10.1158/0008-5472.can-07-5136] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Staudinger JL, Lichti K. Cell signaling and nuclear receptors: new opportunities for molecular pharmaceuticals in liver disease. Mol Pharm 2008; 5:17-34. [PMID: 18159925 PMCID: PMC2387130 DOI: 10.1021/mp700098c] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Liver-enriched nuclear receptors (NRs) collectively function as metabolic and toxicological "sensors" that mediate liver-specific gene-activation in mammals. NR-mediated gene-environment interaction regulates important steps in the hepatic uptake, metabolism, and excretion of glucose, fatty acids, lipoproteins, cholesterol, bile acids, and xenobiotics. Hence, liver-enriched NRs play pivotal roles in the overall control of energy homeostasis in mammals. While it is well-recognized that ligand-binding is the primary mechanism behind activation of NRs, recent research reveals that multiple signal transduction pathways modulate NR-function in liver. The interface between specific signal transduction pathways and NRs helps to determine their overall responsiveness to various environmental and physiological stimuli. In general, phosphorylation of hepatic NRs regulates multiple biological parameters including their transactivation capacity, DNA binding, subcellular location, capacity to interact with protein-cofactors, and protein stability. Certain pathological conditions including inflammation, morbid obesity, hyperlipidemia, atherosclerosis, insulin resistance, and type-2 diabetes are known to modulate selected signal transduction pathways in liver. This review will focus upon recent insights regarding the molecular mechanisms that comprise the interface between disease-mediated activation of hepatic signal transduction pathways and liver-enriched NRs. This review will also highlight the exciting opportunities presented by this new knowledge to develop novel molecular and pharmaceutical strategies for combating these increasingly prevalent human diseases.
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Affiliation(s)
- Jeff L Staudinger
- University of Kansas, Department of Pharmacology and Toxicology, 1251 Wescoe Hall Dr, 5038 Malott Hall, Lawrence, Kansas 66045, USA.
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