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Guzmán C, Benet M, Pisonero-Vaquero S, Moya M, García-Mediavilla MV, Martínez-Chantar ML, González-Gallego J, Castell JV, Sánchez-Campos S, Jover R. The human liver fatty acid binding protein (FABP1) gene is activated by FOXA1 and PPARα; and repressed by C/EBPα: Implications in FABP1 down-regulation in nonalcoholic fatty liver disease. Biochim Biophys Acta Mol Cell Biol Lipids 2013; 1831:803-18. [PMID: 23318274 DOI: 10.1016/j.bbalip.2012.12.014] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2012] [Revised: 11/22/2012] [Accepted: 12/27/2012] [Indexed: 01/24/2023]
Abstract
Liver fatty acid binding protein (FABP1) prevents lipotoxicity of free fatty acids and regulates fatty acid trafficking and partition. Our objective is to investigate the transcription factors controlling the human FABP1 gene and their regulation in nonalcoholic fatty liver disease (NAFLD). Adenovirus-mediated expression of multiple transcription factors in HepG2 cells and cultured human hepatocytes demonstrated that FOXA1 and PPARα are among the most effective activators of human FABP1, whereas C/EBPα is a major dominant repressor. Moreover, FOXA1 and PPARα induced re-distribution of FABP1 protein and increased cytoplasmic expression. Reporter assays demonstrated that the major basal activity of the human FABP1 promoter locates between -96 and -229bp, where C/EBPα binds to a composite DR1-C/EBP element. Mutation of this element at -123bp diminished basal reporter activity, abolished repression by C/EBPα and reduced transactivation by HNF4α. Moreover, HNF4α gene silencing by shRNA in HepG2 cells caused a significant down-regulation of FABP1 mRNA expression. FOXA1 activated the FABP1 promoter through binding to a cluster of elements between -229 and -592bp, whereas PPARα operated through a conserved proximal element at -59bp. Finally, FABP1, FOXA1 and PPARα were concomitantly repressed in animal models of NAFLD and in human nonalcoholic fatty livers, whereas C/EBPα was induced or did not change. We conclude that human FABP1 has a complex mechanism of regulation where C/EBPα displaces HNF4α and hampers activation by FOXA1 and PPARα. Alteration of expression of these transcription factors in NAFLD leads to FABP1 gen repression and could exacerbate lipotoxicity and disease progression.
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Affiliation(s)
- Carla Guzmán
- Experimental Hepatology Unit, IIS Hospital La Fe, Valencia, Spain
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252
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Kim S, Dubrovska A, Salamone RJ, Walker JR, Grandinetti KB, Bonamy GMC, Orth AP, Elliott J, Porta DG, Garcia-Echeverria C, Reddy VA. FGFR2 promotes breast tumorigenicity through maintenance of breast tumor-initiating cells. PLoS One 2013; 8:e51671. [PMID: 23300950 PMCID: PMC3534701 DOI: 10.1371/journal.pone.0051671] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2012] [Accepted: 11/05/2012] [Indexed: 12/26/2022] Open
Abstract
Emerging evidence suggests that some cancers contain a population of stem-like TICs (tumor-initiating cells) and eliminating TICs may offer a new strategy to develop successful anti-cancer therapies. As molecular mechanisms underlying the maintenance of the TIC pool are poorly understood, the development of TIC-specific therapeutics remains a major challenge. We first identified and characterized TICs and non-TICs isolated from a mouse breast cancer model. TICs displayed increased tumorigenic potential, self-renewal, heterogeneous differentiation, and bipotency. Gene expression analysis and immunostaining of TICs and non-TICs revealed that FGFR2 was preferentially expressed in TICs. Loss of FGFR2 impaired self-renewal of TICs, thus resulting in marked decreases in the TIC population and tumorigenic potential. Restoration of FGFR2 rescued the defects in TIC pool maintenance, bipotency, and breast tumor growth driven by FGFR2 knockdown. In addition, pharmacological inhibition of FGFR2 kinase activity led to a decrease in the TIC population which resulted in suppression of breast tumor growth. Moreover, human breast TICs isolated from patient tumor samples were found enriched in a FGFR2+ population that was sufficient to initiate tumor growth. Our data suggest that FGFR2 is essential in sustaining the breast TIC pool through promotion of self-renewal and maintenance of bipotent TICs, and raise the possibility of FGFR2 inhibition as a strategy for anti-cancer therapy by eradicating breast TICs.
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Affiliation(s)
- Sungeun Kim
- Genomics Institute of the Novartis Research Foundation, San Diego, California, United States of America
- * E-mail: (SK); (VAR)
| | - Anna Dubrovska
- The Scripps Research Institute, La Jolla, California, United States of America
| | - Richard J. Salamone
- Genomics Institute of the Novartis Research Foundation, San Diego, California, United States of America
| | - John R. Walker
- Genomics Institute of the Novartis Research Foundation, San Diego, California, United States of America
| | - Kathryn B. Grandinetti
- Genomics Institute of the Novartis Research Foundation, San Diego, California, United States of America
| | - Ghislain M. C. Bonamy
- Genomics Institute of the Novartis Research Foundation, San Diego, California, United States of America
| | - Anthony P. Orth
- Genomics Institute of the Novartis Research Foundation, San Diego, California, United States of America
| | - Jimmy Elliott
- Genomics Institute of the Novartis Research Foundation, San Diego, California, United States of America
| | - Diana Graus Porta
- Novartis Institutes for BioMedical Research, Novartis Pharma AG, Basel, Switzerland
| | | | - Venkateshwar A. Reddy
- Genomics Institute of the Novartis Research Foundation, San Diego, California, United States of America
- * E-mail: (SK); (VAR)
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253
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Nilsson M, Fagman H. Mechanisms of thyroid development and dysgenesis: an analysis based on developmental stages and concurrent embryonic anatomy. Curr Top Dev Biol 2013; 106:123-70. [PMID: 24290349 DOI: 10.1016/b978-0-12-416021-7.00004-3] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Thyroid dysgenesis is the most common cause of congenital hypothyroidism that affects 1 in 3000 newborns. Although a number of pathogenetic mutations in thyroid developmental genes have been identified, the molecular mechanism of disease is unknown in most cases. This chapter summarizes the current knowledge of normal thyroid development and puts the different developmental stages in perspective, from the time of foregut endoderm patterning to the final shaping of pharyngeal anatomy, for understanding how specific malformations may arise. At the cellular level, we will also discuss fate determination of follicular and C-cell progenitors and their subsequent embryonic growth, migration, and differentiation as the different thyroid primordia evolve and merge to establish the final size and shape of the gland.
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Affiliation(s)
- Mikael Nilsson
- Sahlgrenska Cancer Center, Institute of Biomedicine, University of Gothenburg, Göteborg, Sweden.
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254
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Belaguli NS, Zhang M, Brunicardi FC, Berger DH. Forkhead box protein A2 (FOXA2) protein stability and activity are regulated by sumoylation. PLoS One 2012; 7:e48019. [PMID: 23118920 PMCID: PMC3485284 DOI: 10.1371/journal.pone.0048019] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2012] [Accepted: 09/19/2012] [Indexed: 12/29/2022] Open
Abstract
The forkhead box protein A2 (FOXA2) is an important regulator of glucose and lipid metabolism and organismal energy balance. Little is known about how FOXA2 protein expression and activity are regulated by post-translational modifications. We have identified that FOXA2 is post-translationally modified by covalent attachment of a small ubiquitin related modifier-1 (SUMO-1) and mapped the sumoylation site to the amino acid lysine 6 (K6). Preventing sumoylation by mutating the SUMO acceptor K6 to arginine resulted in downregulation of FOXA2 protein but not RNA expression in INS-1E insulinoma cells. K6R mutation also downregulated FOXA2 protein levels in HepG2 hepatocellular carcinoma cells, HCT116 colon cancer cells and LNCaP and DU145 prostate cancer cells. Further, interfering with FOXA2 sumoylation through siRNA mediated knockdown of UBC9, an essential SUMO E2 conjugase, resulted in downregulation of FOXA2 protein levels. Stability of sumoylation deficient FOXA2K6R mutant protein was restored when SUMO-1 was fused in-frame. FOXA2 sumoylation and FOXA2 protein levels were increased by PIAS1 SUMO ligase but not a SUMO ligase activity deficient PIAS1 mutant. Although expressed at lower levels, sumoylation deficient FOXA2K6R mutant protein was detectable in the nucleus indicating that FOXA2 nuclear localization is independent of sumoylation. Sumoylation increased the transcriptional activity of FOXA2 on Pdx-1 area I enhancer. Together, our results show that sumoylation regulates FOXA2 protein expression and activity.
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255
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Abstract
A critical cis-regulatory element for the CFTR (cystic fibrosis transmembrane conductance regulator) gene is located in intron 11, 100 kb distal to the promoter, with which it interacts. This sequence contains an intestine-selective enhancer and associates with enhancer signature proteins, such as p300, in addition to tissue-specific TFs (transcription factors). In the present study we identify critical TFs that are recruited to this element and demonstrate their importance in regulating CFTR expression. In vitro DNase I footprinting and EMSAs (electrophoretic mobility-shift assays) identified four cell-type-selective regions that bound TFs in vitro. ChIP (chromatin immunoprecipitation) identified FOXA1/A2 (forkhead box A1/A2), HNF1 (hepatocyte nuclear factor 1) and CDX2 (caudal-type homeobox 2) as in vivo trans-interacting factors. Mutation of their binding sites in the intron 11 core compromised its enhancer activity when measured by reporter gene assay. Moreover, siRNA (small interfering RNA)-mediated knockdown of CDX2 caused a significant reduction in endogenous CFTR transcription in intestinal cells, suggesting that this factor is critical for the maintenance of high levels of CFTR expression in these cells. The ChIP data also demonstrate that these TFs interact with multiple cis-regulatory elements across the CFTR locus, implicating a more global role in intestinal expression of the gene.
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256
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A novel mammal-specific three partite enhancer element regulates node and notochord-specific Noto expression. PLoS One 2012; 7:e47785. [PMID: 23110100 PMCID: PMC3478275 DOI: 10.1371/journal.pone.0047785] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2012] [Accepted: 09/17/2012] [Indexed: 11/19/2022] Open
Abstract
The vertebrate organizer and notochord have conserved, essential functions for embryonic development and patterning. The restricted expression of developmental regulators in these tissues is directed by specific cis-regulatory modules (CRMs) whose sequence conservation varies considerably. Some CRMs have been conserved throughout vertebrates and likely represent ancestral regulatory networks, while others have diverged beyond recognition but still function over a wide evolutionary range. Here we identify and characterize a mammalian-specific CRM required for node and notochord specific (NNC) expression of NOTO, a transcription factor essential for node morphogenesis, nodal cilia movement and establishment of laterality in mouse. A 523 bp enhancer region (NOCE) upstream the Noto promoter was necessary and sufficient for NNC expression from the endogenous Noto locus. Three subregions in NOCE together mediated full activity in vivo. Binding sites for known transcription factors in NOCE were functional in vitro but dispensable for NOCE activity in vivo. A FOXA2 site in combination with a novel motif was necessary for NOCE activity in vivo. Strikingly, syntenic regions in non-mammalian vertebrates showed no recognizable sequence similarities. In contrast to its activity in mouse NOCE did not drive NNC expression in transgenic fish. NOCE represents a novel, mammal-specific CRM required for the highly restricted Noto expression in the node and nascent notochord and thus regulates normal node development and function.
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257
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Shin DJ, Joshi P, Hong SH, Mosure K, Shin DG, Osborne TF. Genome-wide analysis of FoxO1 binding in hepatic chromatin: potential involvement of FoxO1 in linking retinoid signaling to hepatic gluconeogenesis. Nucleic Acids Res 2012; 40:11499-509. [PMID: 23066095 PMCID: PMC3526316 DOI: 10.1093/nar/gks932] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
The forkhead transcription factor FoxO1 is a critical regulator of hepatic glucose and lipid metabolism, and dysregulation of FoxO1 function has been implicated in diabetes and insulin resistance. We globally identified FoxO1 occupancy in mouse hepatic chromatin on a genome-wide level by chromatin immunoprecipitation coupled with high-throughput DNA sequencing (ChIP-seq). To establish the specific functional significance of FoxO1 against other FoxO proteins, ChIP-seq was performed with chromatin from liver-specific FoxO1 knockout and wild-type mice. Here we identified 401 genome-wide FoxO1-binding locations. Motif search reveals a sequence element, 5′ GTAAACA 3′, consistent with a previously known FoxO1-binding site. Gene set enrichment analysis shows that the data from FoxO1 ChIP-seq are highly correlated with the global expression profiling of genes regulated by FoxO1, demonstrating the functional relevance of our FoxO1 ChIP-seq study. Interestingly, gene ontology analysis reveals the functional significance of FoxO1 in retinoid metabolic processes. We show here that FoxO1 directly binds to the genomic sites for the genes in retinoid metabolism. Notably, deletion of FoxO1 caused a significantly reduced induction of Pck1 and Pdk4 in response to retinoids. As Pck1 and Pdk4 are downstream targets of retinoid signaling, these results suggest that FoxO1 plays a potential role in linking retinoid metabolism to hepatic gluconeogenesis.
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Affiliation(s)
- Dong-Ju Shin
- Department of Molecular Biology and Biochemistry, University of California, Irvine, CA 92697, USA.
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258
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Cancer genetics and genomics of human FOX family genes. Cancer Lett 2012; 328:198-206. [PMID: 23022474 DOI: 10.1016/j.canlet.2012.09.017] [Citation(s) in RCA: 286] [Impact Index Per Article: 23.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2012] [Revised: 09/20/2012] [Accepted: 09/21/2012] [Indexed: 12/16/2022]
Abstract
Forkhead-box (FOX) family proteins, involved in cell growth and differentiation as well as embryogenesis and longevity, are DNA-binding proteins regulating transcription and DNA repair. The focus of this review is on the mechanisms of FOX-related human carcinogenesis. FOXA1 is overexpressed as a result of gene amplification in lung cancer, esophageal cancer, ER-positive breast cancer and anaplastic thyroid cancer and is point-mutated in prostate cancer. FOXA1 overexpression in breast cancer and prostate cancer is associated with good or poor prognosis, respectively. Single nucleotide polymorphism (SNP) within the 5'-UTR of the FOXE1 (TTF2) gene is associated with thyroid cancer risk. FOXF1 overexpression in breast cancer is associated with epithelial-to-mesenchymal transition (EMT). FOXM1 is overexpressed owing to gene amplification in basal-type breast cancer and diffuse large B-cell lymphoma (DLBCL), and it is transcriptionally upregulated owing to Hedgehog-GLI, hypoxia-HIF1α or YAP-TEAD signaling activation. FOXM1 overexpression leads to malignant phenotypes by directly upregulating CCNB1, AURKB, MYC and SKP2 and indirectly upregulating ZEB1 and ZEB2 via miR-200b downregulation. Tumor suppressor functions of FOXO transcription factors are lost in cancer cells as a result of chromosomal translocation, deletion, miRNA-mediated repression, AKT-mediated cytoplasmic sequestration or ubiquitination-mediated proteasomal degradation. FOXP1 is upregulated as a result of gene fusion or amplification in DLBCL and MALT lymphoma and also repression of miRNAs, such as miR-1, miR-34a and miR-504. FOXP1 overexpression is associated with poor prognosis in DLBCL, gastric MALT lymphoma and hepatocellular carcinoma but with good prognosis in breast cancer. In neuroblastoma, the entire coding region of the FOXR1 (FOXN5) gene is fused to the MLL or the PAFAH1B gene owing to interstitial deletions. FOXR1 fusion genes function as oncogenes that repress transcription of FOXO target genes. Whole-genome sequencing data from tens of thousands of human cancers will uncover the mutational landscape of FOX family genes themselves as well as FOX-binding sites, which will be ultimately applied for cancer diagnostics, prognostics, and therapeutics.
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259
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Abstract
Different cell types within a single organism are generally distinguished by strikingly different patterns of gene expression, which are dynamic throughout development and adult life. Distal enhancer elements are key drivers of spatiotemporal specificity in gene regulation. Often located tens of kilobases from their target promoters and functioning in an orientation-independent manner, the identification of bona fide enhancers has proved a formidable challenge. With the development of ChIP-seq, global cataloging of putative enhancers has become feasible. Here, we review the current understanding of the chromatin landscape at enhancers and how these chromatin features enable robust identification of tissue-specific enhancers.
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Affiliation(s)
- Gabriel E Zentner
- Department of Genetics and Genome Sciences, Case Western Reserve University, Cleveland, Ohio 44106, USA
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260
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Itkonen H, Mills IG. Chromatin binding by the androgen receptor in prostate cancer. Mol Cell Endocrinol 2012; 360:44-51. [PMID: 21989426 DOI: 10.1016/j.mce.2011.09.037] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/04/2011] [Accepted: 09/26/2011] [Indexed: 12/11/2022]
Abstract
Alterations in transcriptional programs are fundamental to the development of cancers. The androgen receptor is central to the normal development of the prostate gland and to the development of prostate cancer. To a large extent this is believed to be due to the control of gene expression through the interaction of the androgen receptor with chromatin and subsequently with coregulators and the transcriptional machinery. Unbiased genome-wide studies have recently uncovered the recruitment sites that are gene-distal and intragenic rather than associated with proximal promoter regions. Whilst expression profiles from AR-positive primary prostate tumours and cell lines can directly relate to the AR cistrome in prostate cancer cells, this distribution raises significant challenges in making direct mechanistic connections. Furthermore, extrapolating from datasets assembled in one model to other model systems or clinical samples poses challenges if we are to use the AR-directed transcriptome to guide the development of novel biomarkers or treatment decisions. This review will provide an overview of the androgen receptor before addressing the challenges and opportunities created by whole-genome studies of the interplay between the androgen receptor and chromatin.
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Affiliation(s)
- Harri Itkonen
- Prostate Cancer Research Group, Nordic EMBL Partnership, Centre for Molecular Medicine Norway (NCMM), University of Oslo, P.O. Box 1137 Blindern, 0318 Oslo, Norway.
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261
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Pla2g12b and Hpn are genes identified by mouse ENU mutagenesis that affect HDL cholesterol. PLoS One 2012; 7:e43139. [PMID: 22912808 PMCID: PMC3422231 DOI: 10.1371/journal.pone.0043139] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2012] [Accepted: 07/16/2012] [Indexed: 12/20/2022] Open
Abstract
Despite considerable progress understanding genes that affect the HDL particle, its function, and cholesterol content, genes identified to date explain only a small percentage of the genetic variation. We used N-ethyl-N-nitrosourea mutagenesis in mice to discover novel genes that affect HDL cholesterol levels. Two mutant lines (Hlb218 and Hlb320) with low HDL cholesterol levels were established. Causal mutations in these lines were mapped using linkage analysis: for line Hlb218 within a 12 Mbp region on Chr 10; and for line Hlb320 within a 21 Mbp region on Chr 7. High-throughput sequencing of Hlb218 liver RNA identified a mutation in Pla2g12b. The transition of G to A leads to a cysteine to tyrosine change and most likely causes a loss of a disulfide bridge. Microarray analysis of Hlb320 liver RNA showed a 7-fold downregulation of Hpn; sequencing identified a mutation in the 3′ splice site of exon 8. Northern blot confirmed lower mRNA expression level in Hlb320 and did not show a difference in splicing, suggesting that the mutation only affects the splicing rate. In addition to affecting HDL cholesterol, the mutated genes also lead to reduction in serum non-HDL cholesterol and triglyceride levels. Despite low HDL cholesterol levels, the mice from both mutant lines show similar atherosclerotic lesion sizes compared to control mice. These new mutant mouse models are valuable tools to further study the role of these genes, their affect on HDL cholesterol levels, and metabolism.
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262
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Cho JW, Lee CY, Ko Y. Therapeutic potential of mesenchymal stem cells overexpressing human forkhead box A2 gene in the regeneration of damaged liver tissues. J Gastroenterol Hepatol 2012; 27:1362-70. [PMID: 22432472 PMCID: PMC3492917 DOI: 10.1111/j.1440-1746.2012.07137.x] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
BACKGROUND AND AIM Although a liver transplantation is considered to be the only effective long-term treatment in many cases of liver diseases, it is limited by a lack of donor organs and immune rejection. As an autologous stem cell approach, this study was conducted to assess whether forkhead box A2 (Foxa2) gene overexpression in bone marrow-derived mesenchymal stem cells (MSC) could protect the liver from hepatic diseases by stimulating tissue regeneration after cell transplantation. METHODS Rat MSC (rMSC) were isolated, characterized, and induced to hepatocytes that expressed liver-specific markers. Four different treatments (control [phosphate-buffered saline], rMSC alone, rMSC/pIRES-enhanced green fluorescent protein (EGFP) vector, and rMSC/pIRES-EGFP/human Foxa2) were injected into the spleen of carbon tetrachloride-injured rats. Biochemical and histological analyses on days 30, 60, and 90 post-transplantation were performed to evaluate the therapeutic capacities of MSC overexpressing hFoxa2. RESULTS rMSC transfected with hFoxa2 were induced into hepatogenic linage and expressed several liver-specific genes, such as, Foxa2, α-fetoprotein, cytokeratin-18, hepatocyte nuclear factor-1α, and hepatocyte growth factor. A group of animals treated with MSC/hFoxa2 showed significant recovery of liver-specific enzyme expressions to normal levels at the end of the study (90 days). Furthermore, when compared to the fibrotic areas of the samples treated with MSC alone or MSC/vector, the fibrotic area of the samples treated with rMSC/hFoxa2 for 90 days significantly decreased, until they were completely gone. CONCLUSIONS Human Foxa2 efficiently promoted the incorporation of MSC into liver grafts, suggesting that hFoxa2 genes could be used for the structural or functional recovery of damaged liver cells.
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Affiliation(s)
- Jong-Woo Cho
- Department of Biotechnology, Korea UniversitySeoul, Korea
| | - Chul-Young Lee
- Department of Animal Material Engineering, College of Science and Natural Resource, Gyeongnam National University of Science and TechnologyJinju, Korea
| | - Yong Ko
- Department of Biotechnology, Korea UniversitySeoul, Korea
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263
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Sichero L, Sobrinho JS, Villa LL. Identification of novel cellular transcription factors that regulate early promoters of human papillomavirus types 18 and 16. J Infect Dis 2012; 206:867-74. [PMID: 22740717 DOI: 10.1093/infdis/jis430] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND The long control region (LCR) of human papillomavirus (HPV) regulates early gene transcription by interaction with several viral and cellular transcription factors (TFs). METHODS To identify novel TFs that could influence early expression of HPV type 18 (HPV-18) and HPV type 16 (HPV-16), a high-throughput transfection array was used. RESULTS Among the 704 TFs tested, 28 activated and 36 inhibited the LCR of HPV-18 by more than 2-fold. For validation, C33 cells were cotransfected with increasing amounts of selected TF expression plasmids in addition to LCR-luciferase vectors of different molecular variants of HPV-18 and HPV-16. Among the TFs identified, only GATA3, FOXA1, and MYC have putative binding sites within the LCR sequence, as indicated using the TRANSFAC database. Furthermore, we demonstrated FOXA1 and MYC in vivo binding to the LCR of both HPV types using chromatin immunoprecipitation assay. CONCLUSIONS We identified new TFs implicated in the regulation of the LCR of HPV-18 and HPV-16. Many of these factors are mutated in cancer or are putative cancer biomarkers and could potentially be involved in the regulation of HPV early gene expression.
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Affiliation(s)
- Laura Sichero
- Department of Virology, Ludwig Institute for Cancer Research, São Paulo, SP, Brazil.
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264
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Hammond GL, Wu TS, Simard M. Evolving utility of sex hormone-binding globulin measurements in clinical medicine. Curr Opin Endocrinol Diabetes Obes 2012; 19:183-9. [PMID: 22531107 DOI: 10.1097/med.0b013e328353732f] [Citation(s) in RCA: 67] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
PURPOSE OF REVIEW Sex hormone-binding globulin (SHBG) regulates the plasma levels and biological actions of the sex steroids: testosterone and estradiol. Advances in our understanding of how plasma SHBG levels are determined, and how SHBG functions, have provided insight into how SHBG should be used to assess the actions of its sex-steroid ligands, and as a biomarker of metabolic and endocrine abnormalities. RECENT FINDINGS Plasma SHBG levels fluctuate throughout life in response to the changes in metabolic and physiologic states, and are altered by natural hormones and synthetic steroids. Interindividual differences in plasma SHBG levels and activity are also influenced by polymorphisms within the structural and regulatory regions of the SHBG gene. SUMMARY Measurements of SHBG are widely used to predict plasma free testosterone levels in patients suffering from excess androgen exposures, but have broader utility in assessing the risk for endocrine diseases and clinical sequelae of the metabolic syndrome, namely, type 2 diabetes and cardiovascular disease. It is anticipated that new genetic and functional data regarding SHBG will reveal whether SHBG is simply a biomarker of these diseases or participants in their cause.
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Affiliation(s)
- Geoffrey L Hammond
- Department of Obstetrics and Gynecology, University of British Columbia, Child & Family Research Institute, Vancouver, British Columbia, Canada.
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265
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Abstract
Various studies have demonstrated that somatic differentiated cells can be reprogrammed into other differentiated states or into pluripotency, thus showing that the differentiated cellular state is not irreversible. These findings have generated intense interest in the process of reprogramming and in mechanisms that govern the pluripotent state. However, the realization that differentiated cells can be triggered to switch to considerably different lineages also emphasizes that we need to understand how the identity of mature cells is normally maintained. Here we review recent studies on how the differentiated state is controlled at the transcriptional level and discuss how new insights have begun to elucidate mechanisms underlying the stable maintenance of mature cell identities.
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Affiliation(s)
- Johan Holmberg
- Ludwig Institute for Cancer Research Ltd, BOX 240, Karolinska Institutet, S-171 77 Stockholm, Sweden.
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266
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Ahmed S, Al-Saigh S, Matthews J. FOXA1 Is Essential for Aryl Hydrocarbon Receptor–Dependent Regulation of Cyclin G2. Mol Cancer Res 2012; 10:636-48. [DOI: 10.1158/1541-7786.mcr-11-0502] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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267
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Bischof JM, Ott CJ, Leir SH, Gosalia N, Song L, London D, Furey TS, Cotton CU, Crawford GE, Harris A. A genome-wide analysis of open chromatin in human tracheal epithelial cells reveals novel candidate regulatory elements for lung function. Thorax 2012; 67:385-91. [PMID: 22169360 PMCID: PMC3384740 DOI: 10.1136/thoraxjnl-2011-200880] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
BACKGROUND Distal cell-type-specific regulatory elements may be located at very large distances from the genes that they control and are often hidden within intergenic regions or in introns of other genes. The development of methods that enable mapping of regions of open chromatin genome wide has greatly advanced the identification and characterisation of these elements. METHODS Here we use DNase I hypersensitivity mapping followed by deep sequencing (DNase-seq) to generate a map of open chromatin in primary human tracheal epithelial (HTE) cells and use bioinformatic approaches to characterise the distribution of these sites within the genome and with respect to gene promoters, intronic and intergenic regions. RESULTS Genes with HTE-selective open chromatin at their promoters were associated with multiple pathways of epithelial function and differentiation. The data predict novel cell-type-specific regulatory elements for genes involved in HTE cell function, such as structural proteins and ion channels, and the transcription factors that may interact with them to control gene expression. Moreover, the map of open chromatin can identify the location of potentially critical regulatory elements in genome-wide association studies (GWAS) in which the strongest association is with single nucleotide polymorphisms in non-coding regions of the genome. We demonstrate its relevance to a recent GWAS that identifies modifiers of cystic fibrosis lung disease severity. CONCLUSION Since HTE cells have many functional similarities with bronchial epithelial cells and other differentiated cells in the respiratory epithelium, these data are of direct relevance to elucidating the molecular basis of normal lung function and lung disease.
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Affiliation(s)
- Jared M Bischof
- Human Molecular Genetics Program, Children's Memorial Research Center, Chicago, Illinois, USA
- Department of Pediatrics, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
| | - Christopher J Ott
- Human Molecular Genetics Program, Children's Memorial Research Center, Chicago, Illinois, USA
- Department of Pediatrics, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
| | - Shih-Hsing Leir
- Human Molecular Genetics Program, Children's Memorial Research Center, Chicago, Illinois, USA
- Department of Pediatrics, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
| | - Nehal Gosalia
- Human Molecular Genetics Program, Children's Memorial Research Center, Chicago, Illinois, USA
- Department of Pediatrics, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
| | - Lingyun Song
- Institute for Genome Science and Policy, Duke University, Durham, North Carolina, USA
| | - Darin London
- Institute for Genome Science and Policy, Duke University, Durham, North Carolina, USA
| | - Terrence S Furey
- Department of Genetics, Carolina Center for Genome Sciences, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
- Department of Biology, Carolina Center for Genome Sciences, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - Calvin U Cotton
- Department of Pediatrics, Case Western University, School of Medicine, Cleveland, Ohio, USA
- Department of Physiology and Biophysics, Case Western University, School of Medicine, Cleveland, Ohio, USA
| | - Gregory E Crawford
- Institute for Genome Science and Policy, Duke University, Durham, North Carolina, USA
| | - Ann Harris
- Human Molecular Genetics Program, Children's Memorial Research Center, Chicago, Illinois, USA
- Department of Pediatrics, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
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268
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Clarke CL, Graham JD. Non-overlapping progesterone receptor cistromes contribute to cell-specific transcriptional outcomes. PLoS One 2012; 7:e35859. [PMID: 22545144 PMCID: PMC3335806 DOI: 10.1371/journal.pone.0035859] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2012] [Accepted: 03/23/2012] [Indexed: 12/22/2022] Open
Abstract
The transcriptional effects of the ovarian hormone progesterone are pleiotropic, and binding to DNA of the nuclear progesterone receptor (PR), a ligand-activated transcription factor, results in diverse outcomes in a range of target tissues. To determine whether distinct patterns of genomic interaction of PR contribute to the cell specificity of the PR transcriptome, we have compared the genomic binding sites for PR in breast cancer cells and immortalized normal breast cells. PR binding was correlated with transcriptional outcome in both cell lines, with 60% of progestin-regulated genes associated with one or more PR binding regions. There was a remarkably low overlap between the PR cistromes of the two cell lines, and a similarly low overlap in transcriptional targets. A conserved PR binding element was identified in PR binding regions from both cell lines, but there were distinct patterns of enrichment of known cofactor binding motifs, with FOXA1 sites over-represented in breast cancer cell binding regions and NF1 and AP-1 motifs uniquely enriched in the immortalized normal line. Downstream analyses suggested that differential cofactor availability may generate these distinct PR cistromes, indicating that cofactor levels may modulate PR specificity. Taken together these data suggest that cell-specificity of PR binding is determined by the coordinated effects of key binding cofactors.
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Affiliation(s)
- Christine L. Clarke
- Westmead Institute for Cancer Research, Sydney Medical School –Westmead, University of Sydney at the Westmead Millennium Institute, Westmead Hospital, Westmead, New South Wales, Australia
| | - J. Dinny Graham
- Westmead Institute for Cancer Research, Sydney Medical School –Westmead, University of Sydney at the Westmead Millennium Institute, Westmead Hospital, Westmead, New South Wales, Australia
- * E-mail:
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269
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Roles of lineage-determining transcription factors in establishing open chromatin: lessons from high-throughput studies. Curr Top Microbiol Immunol 2012; 356:1-15. [PMID: 21744305 DOI: 10.1007/82_2011_142] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
The interpretation of the regulatory information of the genome by sequence-specific transcription factors lies at the heart of the specification of cellular identity and function. While most cells in a complex metazoan organism express hundreds of such transcription factors, the underlying mechanisms by which they ultimately achieve their functional locations within different cell types remain poorly understood. Here, we contrast various models of how cell type-specific binding patterns may arise using available evidence from ChIP-Seq experiments obtained in tractable developmental model systems, particularly the hematopoietic system. The data suggests a model whereby relatively small sets of lineage-determining transcription factors jointly compete with nucleosomes to establish their cell type-specific binding patterns. These binding sites gain histone marks indicative of active cis-regulatory elements and define a large fraction of the enhancer-like regions differentiated cell types. The formation of these regions of open chromatin enables the recruitment of secondary transcription factors that contribute additional transcription regulatory functionality required for the cell type-appropriate expression of genes with both general and specialized cellular functions.
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270
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Abdus-Saboor I, Stone CE, Murray JI, Sundaram MV. The Nkx5/HMX homeodomain protein MLS-2 is required for proper tube cell shape in the C. elegans excretory system. Dev Biol 2012; 366:298-307. [PMID: 22537498 DOI: 10.1016/j.ydbio.2012.03.015] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2012] [Revised: 03/26/2012] [Accepted: 03/28/2012] [Indexed: 01/20/2023]
Abstract
Cells perform wide varieties of functions that are facilitated, in part, by adopting unique shapes. Many of the genes and pathways that promote cell fate specification have been elucidated. However, relatively few transcription factors have been identified that promote shape acquisition after fate specification. Here we show that the Nkx5/HMX homeodomain protein MLS-2 is required for cellular elongation and shape maintenance of two tubular epithelial cells in the C. elegans excretory system, the duct and pore cells. The Nkx5/HMX family is highly conserved from sea urchins to humans, with known roles in neuronal and glial development. MLS-2 is expressed in the duct and pore, and defects in mls-2 mutants first arise when the duct and pore normally adopt unique shapes. MLS-2 cooperates with the EGF-Ras-ERK pathway to turn on the LIN-48/Ovo transcription factor in the duct cell during morphogenesis. These results reveal a novel interaction between the Nkx5/HMX family and the EGF-Ras pathway and implicate a transcription factor, MLS-2, as a regulator of cell shape.
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Affiliation(s)
- Ishmail Abdus-Saboor
- Department of Genetics, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA
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271
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Foxa1 and Foxa2 are essential for sexual dimorphism in liver cancer. Cell 2012; 148:72-83. [PMID: 22265403 DOI: 10.1016/j.cell.2011.11.026] [Citation(s) in RCA: 287] [Impact Index Per Article: 23.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2011] [Revised: 08/26/2011] [Accepted: 11/07/2011] [Indexed: 12/12/2022]
Abstract
Hepatocellular carcinoma (HCC) is sexually dimorphic in both rodents and humans, with significantly higher incidence in males, an effect that is dependent on sex hormones. The molecular mechanisms by which estrogens prevent and androgens promote liver cancer remain unclear. Here, we discover that sexually dimorphic HCC is completely reversed in Foxa1- and Foxa2-deficient mice after diethylnitrosamine-induced hepatocarcinogenesis. Coregulation of target genes by Foxa1/a2 and either the estrogen receptor (ERα) or the androgen receptor (AR) was increased during hepatocarcinogenesis in normal female or male mice, respectively, but was lost in Foxa1/2-deficient mice. Thus, both estrogen-dependent resistance to and androgen-mediated facilitation of HCC depend on Foxa1/2. Strikingly, single nucleotide polymorphisms at FOXA2 binding sites reduce binding of both FOXA2 and ERα to their targets in human liver and correlate with HCC development in women. Thus, Foxa factors and their targets are central for the sexual dimorphism of HCC.
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272
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FOXA1: a transcription factor with parallel functions in development and cancer. Biosci Rep 2012; 32:113-30. [PMID: 22115363 DOI: 10.1042/bsr20110046] [Citation(s) in RCA: 155] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
When aberrant, factors critical for organ morphogenesis are also commonly involved in disease progression. FOXA1 (forkhead box A1), also known as HNF3α (hepatocyte nuclear factor 3α), is required for postnatal survival due to its essential role in controlling pancreatic and renal function. In addition to regulating a variety of tissues during embryogenesis and early life, rescue experiments have revealed a specific role for FOXA1 in the postnatal development of the mammary gland and prostate. Activity of the nuclear hormone receptors ERα (oestrogen receptor α) and AR (androgen receptor) is also required for proper development of the mammary gland and prostate respectively. FOXA1 modulates ER and AR function in breast and prostate cancer cells, supporting the postulate that FOXA1 is involved in ER and AR signalling under normal conditions, and that some carcinogenic processes in these tissues stem from hormonally regulated developmental pathways gone awry. In addition to broadly reviewing the function of FOXA1 in various aspects of development and cancer, this review focuses on the interplay of FOXA1/ER and FOXA1/AR, in normal and cancerous mammary and prostate epithelial cells. Given the hormone dependency of both breast and prostate cancer, a thorough understanding of FOXA1's role in both cancer types is critical for battling hormone receptor-positive disease and acquired anti-hormone resistance.
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273
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Deutsch L, Wrage M, Koops S, Glatzel M, Uzunoglu FG, Kutup A, Hinsch A, Sauter G, Izbicki JR, Pantel K, Wikman H. Opposite roles of FOXA1 and NKX2-1 in lung cancer progression. Genes Chromosomes Cancer 2012; 51:618-29. [PMID: 22383183 DOI: 10.1002/gcc.21950] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2011] [Accepted: 01/31/2012] [Indexed: 11/05/2022] Open
Abstract
Gene copy number profiles of primary lung tumors were screened for high-level amplifications. We detected 22 high-level amplifications in various loci, including 14q13. This locus is known to harbor the adenocarcinoma (AC) lineage-specific target gene NKX2-1, which is not expressed in squamous cell carcinoma (SCC). As the 14q amplification was also found in SCC, we investigated whether or not FOXA1 might be the corresponding target gene for SCC. Focusing on these two target genes, we assessed gene amplifications and protein expression of NKX2-1 and FOXA1 in primary lung tumors (n = 554) and brain metastases (n = 68). Primary AC (n = 194) showed positive protein expression of NKX2-1 in 58.2% of the samples compared with 4.2% of primary SCC samples (n = 212). Positive staining for FOXA1 was seen in 34.7% of the SCC samples, which was comparable with 39.6% in the AC samples. For brain metastases, FOXA1 expression was slightly higher in the SCC samples (55.6%) compared with the non-matched primary SCC tumor samples (43.4%), whereas NKX2-1 expression was comparable in both primary tumors and brain metastases. Positive FOXA1 and NKX2-1 expression was associated with a gain or amplification in 34.6% and 28.6% of cases, respectively. The expression of NKX2-1 was associated with early stage and grade among the AC cases. In contrast, FOXA1 expression in SCC was associated with distant metastases as well as an unfavorable survival rate (P = 0.039). These results suggest that both FOXA1 and NKX2-1 may act as lineage-specific target genes within the 14q amplicon with opposite functions in lung cancer.
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Affiliation(s)
- Lena Deutsch
- Department of General-, Visceral- and Thoracic Surgery, University Medical Center Hamburg-Eppendorf, Germany
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274
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Rakhshandehroo M, Stienstra R, de Wit NJ, Bragt MCE, Haluzik M, Mensink RP, Müller M, Kersten S. Plasma mannose-binding lectin is stimulated by PPARα in humans. Am J Physiol Endocrinol Metab 2012; 302:E595-602. [PMID: 22215653 DOI: 10.1152/ajpendo.00299.2011] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
The peroxisome proliferator activated receptor-α (PPARα) is a major transcriptional regulator of lipid metabolism in liver and represents the molecular target for hypolipidemic fibrate drugs. Effects of PPARα on lipid metabolism are partially mediated by circulating proteins such as FGF21 and ANGPTL4. The present study was undertaken to screen for and identify circulating proteins produced by human liver that are under the control of PPARα. Toward that aim, primary human hepatocytes were treated with the synthetic PPARα agonist Wy-14643 and whole genome expression data selected for secreted proteins. Expression of FGF21, ANGPTL4, and mannose-binding lectin (MBL), a soluble mediator of innate immunity and primary component of the lectin branch of the complement system, was markedly upregulated by Wy-14643 in primary human hepatocytes. Mice express two MBL isomers, Mbl1 and Mbl2. Mbl1 mRNA was weakly induced by Wy-14643 in primary mouse hepatocytes and remained unaltered by Wy-14643 in mouse liver. Mbl2 mRNA was unchanged by Wy-14643 in primary mouse hepatocytes and was strongly reduced by Wy-14643 in mouse liver. Remarkably, plasma Mbl1 levels were increased by chronic PPARα activation in lean and obese mice. Importantly, in two independent clinical trials, treatment with the PPARα agonist fenofibrate at 200 mg/day for 6 wk and 3 mo increased plasma MBL levels by 73 (P = 0.0016) and 86% (P = 0.017), respectively. It is concluded that hepatocyte gene expression and plasma levels of MBL are stimulated by PPARα and fenofibrate in humans, linking PPARα to regulation of innate immunity and complement activation in humans and suggesting a possible role of MBL in lipid metabolism.
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Affiliation(s)
- Maryam Rakhshandehroo
- The Netherlands Nutrigenomics Center, Top Institute Food and Nutrition, Wageningen University, Wageningen, The Netherlands
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275
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FOXA1 Promotes Tumor Progression in Prostate Cancer and Represents a Novel Hallmark of Castration-Resistant Prostate Cancer. THE AMERICAN JOURNAL OF PATHOLOGY 2012; 180:848-61. [DOI: 10.1016/j.ajpath.2011.10.021] [Citation(s) in RCA: 102] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/27/2011] [Revised: 09/23/2011] [Accepted: 10/21/2011] [Indexed: 11/19/2022]
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276
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Patel J, Landers KA, Mortimer RH, Richard K. Expression and uptake of the thyroxine-binding protein transthyretin is regulated by oxygen in primary trophoblast placental cells. J Endocrinol 2012; 212:159-67. [PMID: 22045754 DOI: 10.1530/joe-11-0348] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Transplacental delivery of maternal thyroid hormones to the fetus, in particular thyroxine (T₄), is critical in ensuring normal fetal neurological development. The fetus relies on maternal T₄ till around 16 weeks gestation, but mechanisms of placental T₄ transport are not yet fully elucidated. Placenta produces, secretes and takes up the thyroid hormone-binding protein transthyretin (TTR). Many placental genes are regulated by oxygen levels, which are relatively low (1%) in the early first trimester, rising to 3% in the mid first trimester and 8% in the early second trimester and thereafter. We examined the expression and uptake of TTR in isolated primary human placental cytotrophoblast cells cultured under different oxygen concentrations (1, 3, 8, 21% O₂ and 200 μM desferrioxamine (DFO)) for 24 h. We observed sevenfold higher expression of TTR mRNA and protein levels at 1% O₂ than at 8 and 21% O₂. Significant increases were observed after culture at 3% O₂ and following DFO treatment. We observed significantly higher uptake of ¹²⁵I-TTR and Alexa-594-TTR when cells were cultured at 1 and 3% O₂ and in the presence of 200 μM DFO than at 8 and 21% O₂. When JEG-3 choriocarcinoma cells were transfected with TTR promoter reporter constructs, increased luciferase activity was measured in cells cultured at 1 and 3% O₂ in comparison to 8 and 21% O₂. We conclude that placental TTR expression and uptake is increased by the relative hypoxia observed in the first trimester of pregnancy, a time when materno-fetal T₄ transfer is the sole source of fetal T₄.
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Affiliation(s)
- J Patel
- School of Medicine, Royal Brisbane and Women's Hospital, The University of Queensland, Herston, Brisbane, Queensland 4029, Australia
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277
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Bramswig NC, Kaestner KH. Organogenesis and functional genomics of the endocrine pancreas. Cell Mol Life Sci 2012; 69:2109-23. [PMID: 22241333 DOI: 10.1007/s00018-011-0915-z] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2011] [Revised: 12/04/2011] [Accepted: 12/29/2011] [Indexed: 02/06/2023]
Abstract
Functional genomics, the analysis of the wealth of data produced by genome-wide analyses of gene expression, protein-protein, and protein-DNA interactions, has revolutionized biomedical research. Our ability to determine global gene expression profiles, transcription factor-binding sites, and histone modification maps using microarray-based technologies and next-generation sequencing applications has greatly enhanced our understanding of gene regulatory networks and the molecular wiring diagrams of cells and tissues. The organogenesis of the endocrine pancreas involves numerous signaling events within the endoderm-derived pancreatic epithelium and the surrounding mesenchyme, as well as complex transcription factor networks. Detailed understanding of the differentiation process from foregut endoderm to mature endocrine cells has enabled the rational design of in vitro differentiation protocols that coax embryonic stem cells into β-like cells that might enable cell replacement therapy for diabetes in the future. In this review, we summarize the research studies that have utilized genomic tools to elucidate endocrine pancreatic organogenesis.
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Affiliation(s)
- Nuria C Bramswig
- Department of Genetics, Institute for Diabetes, Obesity and Metabolism, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
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278
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Moya M, Benet M, Guzmán C, Tolosa L, García-Monzón C, Pareja E, Castell JV, Jover R. Foxa1 reduces lipid accumulation in human hepatocytes and is down-regulated in nonalcoholic fatty liver. PLoS One 2012; 7:e30014. [PMID: 22238690 PMCID: PMC3253125 DOI: 10.1371/journal.pone.0030014] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2011] [Accepted: 12/08/2011] [Indexed: 02/06/2023] Open
Abstract
Triglyceride accumulation in nonalcoholic fatty liver (NAFL) results from unbalanced lipid metabolism which, in the liver, is controlled by several transcription factors. The Foxa subfamily of winged helix/forkhead box (Fox) transcription factors comprises three members which play important roles in controlling both metabolism and homeostasis through the regulation of multiple target genes in the liver, pancreas and adipose tissue. In the mouse liver, Foxa2 is repressed by insulin and mediates fasting responses. Unlike Foxa2 however, the role of Foxa1 in the liver has not yet been investigated in detail. In this study, we evaluate the role of Foxa1 in two human liver cell models, primary cultured hepatocytes and HepG2 cells, by adenoviral infection. Moreover, human and rat livers were analyzed to determine Foxa1 regulation in NAFL. Results demonstrate that Foxa1 is a potent inhibitor of hepatic triglyceride synthesis, accumulation and secretion by repressing the expression of multiple target genes of these pathways (e.g., GPAM, DGAT2, MTP, APOB). Moreover, Foxa1 represses the fatty acid transporter protein FATP2 and lowers fatty acid uptake. Foxa1 also increases the breakdown of fatty acids by inducing peroxisomal fatty acid β-oxidation and ketone body synthesis. Finally, Foxa1 is able to largely up-regulate UCP1, thereby dissipating energy and consistently decreasing the mitochondria membrane potential. We also report that human and rat NAFL have a reduced Foxa1 expression, possibly through a protein kinase C-dependent pathway. We conclude that Foxa1 is an antisteatotic factor that coordinately tunes several lipid metabolic pathways to block triglyceride accumulation in hepatocytes. However, Foxa1 is down-regulated in human and rat NAFL and, therefore, increasing Foxa1 levels could protect from steatosis. Altogether, we suggest that Foxa1 could be a novel therapeutic target for NAFL disease and insulin resistance.
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Affiliation(s)
- Marta Moya
- Experimental Hepatology Unit, University Hospital La Fe, Valencia, Spain
| | - Marta Benet
- Experimental Hepatology Unit, University Hospital La Fe, Valencia, Spain
- CIBERehd, Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas, Barcelona, Spain
| | - Carla Guzmán
- Experimental Hepatology Unit, University Hospital La Fe, Valencia, Spain
| | - Laia Tolosa
- Experimental Hepatology Unit, University Hospital La Fe, Valencia, Spain
| | - Carmelo García-Monzón
- CIBERehd, Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas, Barcelona, Spain
- Liver Research Unit, Instituto de Investigación Sanitaria Princesa, University Hospital Santa Cristina, Madrid, Spain
| | - Eugenia Pareja
- Surgery and Liver Transplantation Unit, University Hospital La Fe, Valencia, Spain
| | - José Vicente Castell
- Experimental Hepatology Unit, University Hospital La Fe, Valencia, Spain
- CIBERehd, Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas, Barcelona, Spain
- Department of Biochemistry and Molecular Biology, University of Valencia, Valencia, Spain
| | - Ramiro Jover
- Experimental Hepatology Unit, University Hospital La Fe, Valencia, Spain
- CIBERehd, Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas, Barcelona, Spain
- Department of Biochemistry and Molecular Biology, University of Valencia, Valencia, Spain
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279
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Forkhead transcription factor FoxA1 regulates sweat secretion through Bestrophin 2 anion channel and Na-K-Cl cotransporter 1. Proc Natl Acad Sci U S A 2012; 109:1199-203. [PMID: 22223659 DOI: 10.1073/pnas.1117213109] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
Body temperature is maintained in a narrow range in mammals, primarily controlled by sweating. In humans, the dynamic thermoregulatory organ, comprised of 2-4 million sweat glands distributed over the body, can secrete up to 4 L of sweat per day, thereby making it possible to withstand high temperatures and endure prolonged physical stress (e.g., long-distance running). The genetic basis for sweat gland function, however, is largely unknown. We find that the forkhead transcription factor, FoxA1, is required to generate mouse sweating capacity. Despite continued sweat gland morphogenesis, ablation of FoxA1 in mice results in absolute anihidrosis (lack of sweating). This inability to sweat is accompanied by down-regulation of the Na-K-Cl cotransporter 1 (Nkcc1) and the Ca(2+)-activated anion channel Bestrophin 2 (Best2), as well as glycoprotein accumulation in gland lumens and ducts. Furthermore, Best2-deficient mice display comparable anhidrosis and glycoprotein accumulation. These findings link earlier observations that both sodium/potassium/chloride exchange and Ca(2+) are required for sweat production. FoxA1 is inferred to regulate two corresponding features of sweat secretion. One feature, via Best2, catalyzes a bicarbonate gradient that could help to drive calcium-associated ionic transport; the other, requiring Nkcc1, facilitates monovalent ion exchange into sweat. These mechanistic components can be pharmaceutical targets to defend against hyperthermia and alleviate defective thermoregulation in the elderly, and may provide a model relevant to more complex secretory processes.
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280
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Kanamoto N, Tagami T, Ueda-Sakane Y, Sone M, Miura M, Yasoda A, Tamura N, Arai H, Nakao K. Forkhead box A1 (FOXA1) and A2 (FOXA2) oppositely regulate human type 1 iodothyronine deiodinase gene in liver. Endocrinology 2012; 153:492-500. [PMID: 22067325 DOI: 10.1210/en.2011-1310] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Type 1 iodothyronine deiodinase (D1), a selenoenzyme that catalyzes the bioactivation of thyroid hormone, is expressed mainly in the liver. Its expression and activity are modulated by several factors, but the precise mechanism of its transcriptional regulation remains unclear. In the present study, we have analyzed the promoter of human D1 gene (hDIO1) to identify factors that prevalently increase D1 activity in the human liver. Deletion and mutation analyses demonstrated that a forkhead box (FOX)A binding site and an E-box site within the region between nucleotides -187 and -132 are important for hDIO1 promoter activity in the liver. EMSA demonstrated that FOXA1 and FOXA2 specifically bind to the FOXA binding site and that upstream stimulatory factor (USF) specifically binds to the E-box element. Overexpression of FOXA2 decreased hDIO1 promoter activity, and short interfering RNA-mediated knockdown of FOXA2 increased the expression of hDIO1 mRNA. In contrast, overexpression of USF1/2 increased hDIO1 promoter activity. Short interfering RNA-mediated knockdown of FOXA1 decreased the expression of hDIO1 mRNA, but knockdown of both FOXA1 and FOXA2 restored it. The response of the hDIO1 promoter to USF was greatly attenuated in the absence of FOXA1. Taken together, these results indicate that a balance of FOXA1 and FOXA2 expression modulates hDIO1 expression in the liver.
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Affiliation(s)
- Naotetsu Kanamoto
- Department of Medicine and Clinical Science, Kyoto University Graduate School of Medicine, 54 Shogoin Kawahara-cho, Sakyo-ku, Kyoto 606-8507, Japan.
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281
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Dong D, Meng L, Yu Q, Tan G, Ding M, Tan Y. Stable expression of FoxA1 promotes pluripotent P19 embryonal carcinoma cells to be neural stem-like cells. Gene Expr 2012; 15:153-62. [PMID: 22783724 PMCID: PMC6043842 DOI: 10.3727/105221612x13372578119571] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
FoxA1 belongs to the fork head/winged-helix transcription factor family and participates in stimulating neuronal differentiation of pluripotent stem cells at early stages. To explore the biological roles of FoxA1 during this process, the stable expression of a GFP-FoxA1 fusion protein was established in P19 pluripotent embryonal carcinoma cells. Although they still express pluripotency-related transcription factors such as Oct4, Nanog, and Sox2, the generated P19 GFPFoxA1 cells exhibited a decreased activity of alkaline phosphatase and an increased expression of SSEA-3 compared with P19 cells. Elevated levels of nestin expression and prominin-1+ populations were observed in P19 GFPFoxA1 cells, implicating that the stable expression of FoxA1 promoted P19 cells to gain partial characteristics of neural stem cells. Furthermore, the promoter of nestin was confirmed to be bound and activated by FoxA1 directly. The expression of neuron-specific marker tubulin betaIII also existed in P19 GFPFoxA1 cells. P19 GFPFoxA1 cells showed an earlier onset of differentiation during RA-induced neuronal differentiation, evidenced by a more rapid change on the Nanog decrease and the tubulin betaIII increase. Thus, overexpression of FoxA1 alone may promote pluripotent P19 cells to become neural stem-like cells.
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Affiliation(s)
- Difei Dong
- State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Biology, Hunan University, Changsha, Hunan, China
| | - Lei Meng
- State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Biology, Hunan University, Changsha, Hunan, China
| | - Qiqi Yu
- State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Biology, Hunan University, Changsha, Hunan, China
| | - Guixiang Tan
- State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Biology, Hunan University, Changsha, Hunan, China
| | - Miao Ding
- State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Biology, Hunan University, Changsha, Hunan, China
| | - Yongjun Tan
- State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Biology, Hunan University, Changsha, Hunan, China
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282
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Dong X, Zhai Y, Zhang J, Sun Z, Chen J, Chen J, Zhang W. Fork head transcription factor is required for ovarian mature in the brown planthopper, Nilaparvata lugens (Stål). BMC Mol Biol 2011; 12:53. [PMID: 22208615 PMCID: PMC3288825 DOI: 10.1186/1471-2199-12-53] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2011] [Accepted: 12/31/2011] [Indexed: 11/10/2022] Open
Abstract
Background The brown planthopper (BPH), Nilaparvata lugens, is the most devastating rice pest in many areas throughout Asia. The reproductive system of female N. lugens consists of a pair of ovaries with 24-33 ovarioles per ovary in most individuals which determine its fecundity. The fork head (Fox) is a transcriptional regulatory molecule, which regulates and controls many physiological processes in eukaryotes. The Fox family has several subclasses and members, and several Fox factors have been reported to be involved in regulating fecundity. Results We have cloned a fork head gene in N. lugens. The full-length cDNA of NlFoxA is 1789 bp and has an open reading frame of 1143 bp, encoding a protein of 380 amino acids. Quantitative real-time PCR (RT-qPCR) and Reverse Transcription- PCR (RT-PCR) analysis revealed that NlFoxA mRNA was mainly expressed in the fat body, midgut, cuticle and Malpighian tube, and was expressed continuously with little change during all the developmental stages. NlFoxA belongs to the FoxA subfamily of the Fox transcription factors. Knockdown of NlFoxA expression by RNAi using artificial diet containing double-stranded RNA (dsRNA) significantly decreased the number of offspring and impacted the development of ovaries. ELISA and Western blot analyses showed that feeding-based RNAi of NlFoxA gene also resulted in decreased expression of vitellogenin (Vg) protein. Conclusion NlFoxA plays an important role in regulation of fecundity and development of ovaries in the BPH via regulating vitellogenin expression.
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Affiliation(s)
- Xiaolin Dong
- School of Life Sciences, Sun Yat-sen University, Guangzhou, Guangdong, 510275 China
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283
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Integrated microarray and ChIP analysis identifies multiple Foxa2 dependent target genes in the notochord. Dev Biol 2011; 360:415-25. [DOI: 10.1016/j.ydbio.2011.10.002] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2010] [Revised: 09/26/2011] [Accepted: 10/01/2011] [Indexed: 11/20/2022]
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284
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Abstract
The ways in which epigenetic modifications fix the effects of early environmental events, ensuring sustained responses to transient stimuli that result in modified gene expression patterns and phenotypes later in life, are a topic of considerable interest. This article focuses on recently discovered mechanisms and calls into question prevailing views about the dynamics, positions, and functions of epigenetic marks. Most epigenetic studies have addressed the long-term effects of environmental stressors on a small number of epigenetic marks, at the global or individual gene level, in humans and in animal models. In parallel, increasing numbers of studies based on high-throughput technologies are revealing additional complexity in epigenetic processes by highlighting the importance of crosstalk between different epigenetic marks in humans and mice. A number of studies focusing on metabolic programming and the developmental origin of health and disease have identified links between early nutrition, epigenetic processes, and long-term illness. The existence of a self-propagating epigenetic cycle has been shown. Moreover, recent studies have shown an obvious sexual dimorphism both for programming trajectories and in response to the same environmental insult. Despite recent progress, however, we are still far from understanding how, when, and where environmental stressors disturb key epigenetic mechanisms. Thus, the need to identify original key marks and monitor the changes they undergo throughout development, during an individual's lifetime, or over several generations remains a challenging issue.
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Affiliation(s)
- Anne Gabory
- INRA, UMR 1198 Biologie du Développement et Reproduction, Jouy-en-Josas, France
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285
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Gabory A, Attig L, Junien C. Epigenetic mechanisms involved in developmental nutritional programming. World J Diabetes 2011; 2:164-75. [PMID: 22010058 PMCID: PMC3196195 DOI: 10.4239/wjd.v2.i10.164] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/02/2011] [Revised: 08/31/2011] [Accepted: 09/08/2011] [Indexed: 02/05/2023] Open
Abstract
The ways in which epigenetic modifications fix the effects of early environmental events, ensuring sustained responses to transient stimuli, which result in modified gene expression patterns and phenotypes later in life, is a topic of considerable interest. This review focuses on recently discovered mechanisms and calls into question prevailing views about the dynamics, position and functions of epigenetic marks. Most epigenetic studies have addressed the long-term effects on a small number of epigenetic marks, at the global or individual gene level, of environmental stressors in humans and animal models. In parallel, increasing numbers of studies based on high-throughput technologies and focusing on humans and mice have revealed additional complexity in epigenetic processes, by highlighting the importance of crosstalk between the different epigenetic marks. A number of studies focusing on the developmental origin of health and disease and metabolic programming have identified links between early nutrition, epigenetic processes and long-term illness. The existence of a self-propagating epigenetic cycle has been demonstrated. Moreover, recent studies demonstrate an obvious sexual dimorphism both for programming trajectories and in response to the same environmental insult. Despite recent progress, we are still far from understanding how, when and where environmental stressors disturb key epigenetic mechanisms. Thus, identifying the original key marks and their changes throughout development during an individual’s lifetime or over several generations remains a challenging issue.
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Affiliation(s)
- Anne Gabory
- Anne Gabory, Linda Attig, Claudine Junien, Developmental Biology and Reproduction, National Institute for Agronomic Research, National Veterinary school, National Center For Scientific Research, Jouy en Josas, France
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286
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Wada K, Maeda YY, Watanabe K, Oshio T, Ueda T, Takahashi G, Yokohama M, Saito J, Seki Y, Takahama S, Ishii R, Shitara H, Taya C, Yonekawa H, Kikkawa Y. A deletion in a cis element of Foxe3 causes cataracts and microphthalmia in rct mice. Mamm Genome 2011; 22:693-702. [PMID: 22002806 DOI: 10.1007/s00335-011-9358-y] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2011] [Accepted: 09/23/2011] [Indexed: 01/25/2023]
Abstract
The Rinshoken cataract (rct) mutation, which causes congenital cataracts, is a recessive mutation found in SJL/J mice. All mutants present with opacity in the lens by 2 months of age. The rct locus was mapped to a 1.6-Mb region in Chr 4 that contains the Foxe3 gene. This gene is responsible for cataracts in humans and mice, and it plays a crucial role in the development of the lens. Furthermore, mutation of Foxe3 causes various ocular defects. We sequenced the genomic region of Foxe3, including the coding exons and UTRs; however, no mutations were discovered in these regions. Because there were no differences in Foxe3 sequences between the rct/rct and wild-type mice, we inferred that a mutation was located in the regulatory regions of the Foxe3 gene. To test this possibility, we sequenced a 5' noncoding region that is highly conserved among vertebrates and is predicted to be the major enhancer of Foxe3. This analysis revealed a deletion of 22-bp located approximately 3.2-kb upstream of the start codon of Foxe3 in rct mice. Moreover, we demonstrated by RT-PCR and in situ hybridization that the rct mutant has reduced expression of Foxe3 in the lens during development. We therefore suggest that cataracts in rct mice are caused by reduced Foxe3 expression in the lens and that this decreased expression is a result of a deletion in a cis-acting regulatory element.
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Affiliation(s)
- Kenta Wada
- Department of Bioproduction, Tokyo University of Agriculture, Abashiri, Hokkaido, Japan
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287
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Jin HS, Sõber S, Hong KW, Org E, Kim BY, Laan M, Oh B, Jeong SY. Age-dependent association of the polymorphisms in the mitochondria-shaping gene, OPA1, with blood pressure and hypertension in Korean population. Am J Hypertens 2011; 24:1127-35. [PMID: 21796221 DOI: 10.1038/ajh.2011.131] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
BACKGROUND Essential hypertension is associated with mitochondrial dysfunction. Because mitochondrial dynamics; mitochondrial morphological changes are closely linked with various mitochondrial functions, we aimed to examine whether the genetic variation of the mitochondria-shaping genes influenced the susceptibility to blood pressure (BP) and hypertension. METHODS The quantitative BP trait analysis and hypertension case-control analysis for the total 52 single-nucleotide polymorphisms (SNPs) in the five major mitochondria-shaping genes were performed in the Korean Association Resource (KARE) study cohort (8,512 subjects). RESULTS In the total subjects of the KARE study cohort, there were no statistically significant associations of the SNPs in the five mitochondria-shaping genes with BP or hypertension after adjusting for multiple tests. However, the age group analysis in the 40s, 50s, and 60s age subgroups revealed that 15 SNPs out of 26 SNPs genotyped in the OPA1 gene were significantly associated with BP and/or hypertension in the 60s age subgroup and their association P values satisfied the Bonferroni-corrected significance level (P < 0.00625). Noticeably, nine SNPs were consistently associated with all the three traits; systolic BP (SBP), diastolic BP (DBP), and hypertension. In silico lookup of the associated SNPs in the Southern German population did not reveal associations with BP traits. CONCLUSIONS Our results indicate that genetic variation of the mitochondrial fusion-regulating gene, OPA1, might be associated with BP and hypertension in an age-dependent and population-specific manner in the Korean study cohort, and suggest that altered mitochondrial dynamics, especially involved in the mitochondrial fusion event, may play an important role in the pathogenesis of hypertension.
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288
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Abstract
The development of the endocrine pancreas and the differentiation of its five cell types, α, β, δ, ε and pancreatic polypeptide (PP) cells, are a highly complex and tightly regulated process. Proper differentiation and function of α- and β-cells are critical for blood glucose homeostasis. These processes are governed by multiple transcription factors and other signalling systems, and its dysregulation results in diabetes. The differentiation of α-cells and the maintenance of α-cell function can be influenced at several stages during development and in the maturing islet. Many transcription factors, such as neurogenin 3 (Ngn3), pancreatic duodenal homeobox 1 (Pdx1) and regulatory factor x6 (Rfx6), play a crucial role in the determination of the endocrine cell fate, while other transcription factors, such as aristaless-related homeobox (Arx) and forkhead box A2 (Foxa2), are implicated in the initial or terminal differentiation of α-cells. In vivo and in vitro studies have shown that preproglucagon transcription, and therefore the maintenance of α-cell function, is regulated by several factors, including forkhead box A1 (Foxa1), paired box 6 (Pax6), brain4 (Brn4) and islet-1 (Isl-1). Detailed information about the regulation of normal and abnormal α-cell differentiation gives insight into the pathogenesis of diabetes, identifies further targets for diabetes treatment and provides clues for the reprogramming of α- to β-cells for replacement therapy.
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Affiliation(s)
- N C Bramswig
- Department of Genetics, Institute of Diabetes, Obesity and Metabolism, University of Pennsylvania School of Medicine, Philadelphia, PA 19104, USA
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289
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Hirai H, Tani T, Kikyo N. Structure and functions of powerful transactivators: VP16, MyoD and FoxA. THE INTERNATIONAL JOURNAL OF DEVELOPMENTAL BIOLOGY 2011; 54:1589-96. [PMID: 21404180 DOI: 10.1387/ijdb.103194hh] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Induced pluripotent stem cell (iPSC) technology is a promising approach for converting one type of a differentiated cell into another type of differentiated cell through a pluripotent state as an intermediate step. Recent studies, however, indicate the possibility of directly converting one cell type to another without going through a pluripotent state. This direct reprogramming approach is dependent on a combination of highly potent transcription factors for cell-type conversion, presumably skipping more physiological and multi-step differentiation processes. A trial-and-error strategy is commonly used to screen many candidate transcription factors to identify the correct combination of factors. We speculate, however, that a better understanding of the functional mechanisms of exemplary transcriptional activators will facilitate the identification of novel factor combinations capable of direct reprogramming. The purpose of this review is to critically examine the literature on three highly potent transcriptional activators: the herpes virus protein, VP16; the master regulator of skeletal muscle differentiation, MyoD and the "pioneer" factor for hepatogenesis, FoxA. We discuss the roles of their functional protein domains, interacting partners and chromatin remodeling mechanisms during gene activation to understand how these factors open the chromatin of inactive genes and reset the transcriptional pattern during cell type conversion.
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290
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When urothelial differentiation pathways go wrong: implications for bladder cancer development and progression. Urol Oncol 2011; 31:802-11. [PMID: 21924649 DOI: 10.1016/j.urolonc.2011.07.017] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2011] [Revised: 07/27/2011] [Accepted: 07/28/2011] [Indexed: 12/23/2022]
Abstract
Differentiation is defined as the ability of a cell to acquire full functional behavior. For instance, the function of bladder urothelium is to act as a barrier to the diffusion of solutes into or out of the urine after excretion by the kidney. The urothelium also serves to protect the detrusor muscle from toxins present in stored urine. A major event in the initiation and progression of bladder cancer is loss of urothelial differentiation. This is important because less differentiated urothelial tumors (higher histologic tumor grade) are typically associated with increased biologic and clinical aggressiveness. The differentiation status of urothelial carcinomas can be assessed by histopathologic examination and is reflected in the assignment of a histologic grade (low-grade or high-grade). Although typically limited to morphologic evaluation in most routine diagnostic practices, tumor grade can also be assessed using biochemical markers. Indeed, current pathological analysis of tumor specimens is increasingly reliant on molecular phenotyping. Thus, high priorities for bladder cancer research include identification of (1) biomarkers that will enable the identification of high grade T1 tumors that pose the most threat and require the most aggressive treatment; (2) biomarkers that predict the likelihood that a low grade, American Joint Committee on Cancer stage pTa bladder tumor will progress into an invasive carcinoma with metastatic potential; (3) biomarkers that indicate which pTa tumors are most likely to recur, thus enabling clinicians to prospectively identify patients who require aggressive treatment; and (4) how these markers might contribute to biological processes that underlie tumor progression and metastasis, potentially through loss of terminal differentiation. This review will discuss the proteins associated with urothelial cell differentiation, with a focus on those implicated in bladder cancer, and other proteins that may be involved in neoplastic progression. It is hoped that ongoing discoveries associated with the study of these differentiation-promoting proteins can be translated into the clinic to positively impact patient care.
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291
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Sahu B, Laakso M, Ovaska K, Mirtti T, Lundin J, Rannikko A, Sankila A, Turunen JP, Lundin M, Konsti J, Vesterinen T, Nordling S, Kallioniemi O, Hautaniemi S, Jänne OA. Dual role of FoxA1 in androgen receptor binding to chromatin, androgen signalling and prostate cancer. EMBO J 2011; 30:3962-76. [PMID: 21915096 DOI: 10.1038/emboj.2011.328] [Citation(s) in RCA: 285] [Impact Index Per Article: 21.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2011] [Accepted: 08/16/2011] [Indexed: 12/23/2022] Open
Abstract
High androgen receptor (AR) level in primary tumour predicts increased prostate cancer-specific mortality. However, the mechanisms that regulate AR function in prostate cancer are poorly known. We report here a new paradigm for the forkhead protein FoxA1 action in androgen signalling. Besides pioneering the AR pathway, FoxA1 depletion elicited extensive redistribution of AR-binding sites (ARBs) on LNCaP-1F5 cell chromatin that was commensurate with changes in androgen-dependent gene expression signature. We identified three distinct classes of ARBs and androgen-responsive genes: (i) independent of FoxA1, (ii) pioneered by FoxA1 and (iii) masked by FoxA1 and functional upon FoxA1 depletion. FoxA1 depletion also reprogrammed AR binding in VCaP cells, and glucocorticoid receptor binding and glucocorticoid-dependent signalling in LNCaP-1F5 cells. Importantly, FoxA1 protein level in primary prostate tumour had significant association to disease outcome; high FoxA1 level was associated with poor prognosis, whereas low FoxA1 level, even in the presence of high AR expression, predicted good prognosis. The role of FoxA1 in androgen signalling and prostate cancer is distinctly different from that in oestrogen signalling and breast cancer.
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Affiliation(s)
- Biswajyoti Sahu
- Institute of Biomedicine, Physiology, Biomedicum Helsinki, University of Helsinki, Helsinki, Finland
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292
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Zhang C, Wang L, Wu D, Chen H, Chen Z, Thomas-Ahner JM, Zynger DL, Eeckhoute J, Yu J, Luo J, Brown M, Clinton SK, Nephew KP, Huang THM, Li W, Wang Q. Definition of a FoxA1 Cistrome that is crucial for G1 to S-phase cell-cycle transit in castration-resistant prostate cancer. Cancer Res 2011; 71:6738-6748. [PMID: 21900400 DOI: 10.1158/0008-5472.can-11-1882] [Citation(s) in RCA: 81] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The enhancer pioneer transcription factor FoxA1 is a global mediator of steroid receptor (SR) action in hormone-dependent cancers. In castration-resistant prostate cancer (CRPC), FoxA1 acts as an androgen receptor cofactor to drive G₂ to M-phase cell-cycle transit. Here, we describe a mechanistically distinct SR-independent role for FoxA1 in driving G₁ to S-phase cell-cycle transit in CRPC. By comparing FoxA1 binding sites in prostate cancer cell genomes, we defined a codependent set of FoxA1-MYBL2 and FoxA1-CREB1 binding sites within the regulatory regions of the Cyclin E2 and E2F1 genes that are critical for CRPC growth. Binding at these sites upregulate the Cyclin E2 and Cyclin A2 genes in CRPC but not in earlier stage androgen-dependent prostate cancer, establishing a stage-specific role for this pathway in CRPC growth. Mechanistic investigations indicated that FoxA1, MYBL2, or CREB1 induction of histone H3 acetylation facilitated nucleosome disruption as the basis for codependent transcriptional activation and G₁ to S-phase cell-cycle transit. Our findings establish FoxA1 as a pivotal driver of the cell-cycle in CRPC which promotes G₁ to S-phase transit as well as G₂ to M-phase transit through two distinct mechanisms.
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Affiliation(s)
- Chunpeng Zhang
- Department of Molecular and Cellular Biochemistry and the Comprehensive Cancer Center, The Ohio State University College of Medicine, Columbus, Ohio
| | - Liguo Wang
- Division of Biostatistics, Dan L. Duncan Cancer Center and Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, Texas
| | - Dayong Wu
- Department of Molecular and Cellular Biochemistry and the Comprehensive Cancer Center, The Ohio State University College of Medicine, Columbus, Ohio
| | - Hongyan Chen
- Department of Molecular and Cellular Biochemistry and the Comprehensive Cancer Center, The Ohio State University College of Medicine, Columbus, Ohio
| | - Zhong Chen
- Department of Molecular and Cellular Biochemistry and the Comprehensive Cancer Center, The Ohio State University College of Medicine, Columbus, Ohio
| | - Jennifer M Thomas-Ahner
- Division of Medical Oncology, Department of Internal Medicine and the Comprehensive Cancer Center, The Ohio State University College of Medicine, Columbus, Ohio
| | - Debra L Zynger
- Department of Pathology, The Ohio State University College of Medicine, Columbus, Ohio
| | - Jérôme Eeckhoute
- INSERM UMR 1011-Bâtiment J&K, Université Lille-Nord de France, Faculté de Médecine de, Lille-Pôle Recherche, Boulevard du Professeur Leclerc, Lille cedex, France
| | - Jindan Yu
- Department of Medicine and Robert H. Lurie Comprehensive Cancer Center, Northwestern University Feinberg School of Medicine, Chicago, Illinois
| | - Jun Luo
- Department of Urology, The Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Myles Brown
- Department of Medical Oncology, Dana-Farber Cancer Institute and Harvard Medical School, Boston, Massachusetts
| | - Steven K Clinton
- Division of Medical Oncology, Department of Internal Medicine and the Comprehensive Cancer Center, The Ohio State University College of Medicine, Columbus, Ohio
| | - Kenneth P Nephew
- Medical Sciences Program, Department of Cellular and Integrative Physiology, Indiana University School of Medicine, Bloomington, Indiana
| | - Tim H-M Huang
- Human Cancer Genetics Program, Department of Molecular Virology, Immunology, and Medical Genetics, The Ohio State University, Columbus, Ohio
| | - Wei Li
- Division of Biostatistics, Dan L. Duncan Cancer Center and Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, Texas
| | - Qianben Wang
- Department of Molecular and Cellular Biochemistry and the Comprehensive Cancer Center, The Ohio State University College of Medicine, Columbus, Ohio
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293
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Bao B, Hong B, Feng QL, Xu WH. Transcription factor fork head regulates the promoter of diapause hormone gene in the cotton bollworm, Helicoverpa armigera, and the modification of SUMOylation. INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2011; 41:670-679. [PMID: 21575721 DOI: 10.1016/j.ibmb.2011.04.009] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/28/2011] [Revised: 03/28/2011] [Accepted: 04/25/2011] [Indexed: 05/30/2023]
Abstract
The transcription factor fork head (FoxA) plays important roles in development and metabolism. Here, we cloned a fork head gene in Helicoverpa armigera, and found that the fork head protein is mainly located in the nucleus. This fork head gene belongs to the FoxA subfamily of the Fox transcription factors. The diapause hormone and pheromone biosynthesis-activating neuropeptide (DH-PBAN), which are two well-documented insect neuropeptides that regulate insect development and pheromone biosynthesis, are encoded by a single mRNA. In the present study, fork head was shown to bind strongly to the promoter of H. armigera DH-PBAN gene, and regulate its promoter activity. Furthermore, the effect of SUMOylation of the FH protein on the regulation of Har-DH-PBAN gene was investigated, and we show that the SUMO can modify Har-FH protein and cause down-regulation of DH-PBAN gene expression. These results suggest that SUMOylated FH plays a key role in insect diapause in H. armigera.
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Affiliation(s)
- Bin Bao
- State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-Sen (Zhongshan) University, Guangzhou 510275, China
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294
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Tian J, Zhao W, Tian S, Slater JM, Deng Z, Gridley DS. Expression of Genes Involved in Mouse Lung Cell Differentiation/Regulation after Acute Exposure to Photons and Protons with or without Low-Dose Preirradiation. Radiat Res 2011; 176:553-64. [DOI: 10.1667/rr2601.1] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Affiliation(s)
- Jian Tian
- Department of Radiation Medicine, Radiation Research Laboratories, Loma Linda University, Loma Linda, California
| | - WeiLing Zhao
- Department of Radiation Oncology, Wake Forest University School of Medicine, Winston-Salem, North Carolina
| | - Sisi Tian
- School of Medicine, Loma Linda University, Loma Linda, California
| | - James M. Slater
- Department of Radiation Medicine, Radiation Research Laboratories, Loma Linda University, Loma Linda, California
| | - Zhiyong Deng
- Department of Radiation Oncology, Wake Forest University School of Medicine, Winston-Salem, North Carolina
| | - Daila S. Gridley
- Department of Radiation Medicine, Radiation Research Laboratories, Loma Linda University, Loma Linda, California
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295
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Kranz AL, Eils R, König R. Enhancers regulate progression of development in mammalian cells. Nucleic Acids Res 2011; 39:8689-702. [PMID: 21785139 PMCID: PMC3203619 DOI: 10.1093/nar/gkr602] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
During development and differentiation of an organism, accurate gene regulation is central for cells to maintain and balance their differentiation processes. Transcriptional interactions between cis-acting DNA elements such as promoters and enhancers are the basis for precise and balanced transcriptional regulation. We identified modules of combinations of binding sites in proximal and distal regulatory regions upstream of all transcription start sites (TSSs) in silico and applied these modules to gene expression time-series of mouse embryonic development and differentiation of human stem cells. In addition to tissue-specific regulation controlled by combinations of transcription factors (TFs) binding at promoters, we observed that in particular the combination of TFs binding at promoters together with TFs binding at the respective enhancers regulate highly specifically temporal progression during development: whereas 40% of TFs were specific for time intervals, 79% of TF pairs and even 97% of promoter-enhancer modules showed specificity for single time intervals of the human stem cells. Predominantly SP1 and E2F contributed to temporal specificity at promoters and the forkhead (FOX) family of TFs at enhancer regions. Altogether, we characterized three classes of TFs: with binding sites being enriched at the TSS (like SP1), depleted at the TSS (like FOX), and rather uniformly distributed.
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Affiliation(s)
- Anna-Lena Kranz
- Department of Bioinformatics and Functional Genomics, Institute of Pharmacy and Molecular Biotechnology, and Bioquant, University of Heidelberg, INF 267, 69120 Heidelberg, Germany
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296
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Ponnikorn S, Panichakul T, Sresanga K, Wongborisuth C, Roytrakul S, Hongeng S, Tungpradabkul S. Phosphoproteomic analysis of apoptotic hematopoietic stem cells from hemoglobin E/β-thalassemia. J Transl Med 2011; 9:96. [PMID: 21702968 PMCID: PMC3142509 DOI: 10.1186/1479-5876-9-96] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2011] [Accepted: 06/25/2011] [Indexed: 01/20/2023] Open
Abstract
Background Hemoglobin E/β-thalassemia is particularly common in Southeast Asia and has variable symptoms ranging from mild to severe anemia. Previous investigations demonstrated the remarkable symptoms of β-thalassemia in terms of the acceleration of apoptotic cell death. Ineffective erythropoiesis has been studied in human hematopoietic stem cells, however the distinct apoptotic mechanism was unclear. Methods The phosphoproteome of bone marrow HSCs/CD34+ cells from HbE/β-thalassemic patients was analyzed using IMAC phosphoprotein isolation followed by LC-MS/MS detection. Decyder MS software was used to quantitate differentially expressed proteins in 3 patients and 2 normal donors. The differentially expressed proteins from HSCs/CD34+ cells were compared with HbE/β-thalassemia and normal HSCs. Results A significant change in abundance of 229 phosphoproteins was demonstrated. Importantly, the analysis of the candidate proteins revealed a high abundance of proteins that are commonly found in apoptotic cells including cytochrome C, caspase 6 and apoptosis inducing factors. Moreover, in the HSCs patients a significant increase was observed in a specific type of phosphoserine/threonine binding protein, which is known to act as an important signal mediator for the regulation of cell survival and apoptosis in HbE/β-thalassemia. Conclusions Our study used a novel method to investigate proteins that influence a particular pathway in a given disease or physiological condition. Ultimately, phosphoproteome profiling in HbE/β-thalassemic stem cells is an effective method to further investigate the cell death mechanism of ineffective erythropoiesis in β-thalassemia. Our report provides a comprehensive phosphoproteome, an important resource for the study of ineffective erythropoiesis and developing therapies for HbE/β-thalassemia.
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Affiliation(s)
- Saranyoo Ponnikorn
- Department of Biochemistry, Faculty of Science, Mahidol University, Bangkok, Thailand
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297
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Zheng JY, Zou JJ, Wang WZ, Feng XY, Shi YY, Zhao Y, Jin G, Liu ZM. Tumor necrosis factor-α increases angiopoietin-like protein 2 gene expression by activating Foxo1 in 3T3-L1 adipocytes. Mol Cell Endocrinol 2011; 339:120-9. [PMID: 21501655 DOI: 10.1016/j.mce.2011.04.002] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/13/2010] [Revised: 03/29/2011] [Accepted: 04/01/2011] [Indexed: 01/22/2023]
Abstract
Angiopoietin-like protein 2 (Angptl2) is a key adipocyte-derived inflammatory mediator linking obesity to systemic insulin resistance, which is overexpressed in obesity and related metabolic diseases. However, its regulatory mechanism remains unclear. In this study, we showed that tumor necrosis factor (TNF)-α treatment increased the expression of Angptl2 gene in 3T3-L1 adipocytes. The cloning and sequence analysis of the Angptl2 gene promoter revealed the presence of several putative-binding sites for transcriptional factors, including two IREs. Insulin suppressed Angptl2 mRNA expression in dose-dependent manners, which could be attenuated by a phosphoinositide 3-kinase (PI3K) inhibitor LY294002. The interactions between IRE sites within Angptl2 promoter and forkhead transcription factor Foxo1 were identified by EMSA and ChIP assay. Furthermore, lentivirus-mediated knockdown of Foxo1 expression inhibited the transcriptional activity of Angptl2 promoter and decreased Angptl2 mRNA expression. Finally, TNF-α inhibited Foxo1 phosphorylation and enhanced its transcriptional activity, through which TNF-α increased the expression of Angptl2 in adipocytes. These results suggest that TNF-α up-regulates Angptl2 mRNA expression via PI3K/Foxo1 pathway in 3T3-L1 adipocytes, which may be involved in obesity-induced inflammation and insulin resistance.
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Affiliation(s)
- Jiao-Yang Zheng
- Department of Endocrinology, Changzheng Hospital, Second Military Medical University, Shanghai 200003, China
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298
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Qi J, Pellecchia M, Ronai ZA. The Siah2-HIF-FoxA2 axis in prostate cancer – new markers and therapeutic opportunities. Oncotarget 2011; 1:379-85. [PMID: 21037926 PMCID: PMC2964873 DOI: 10.18632/oncotarget.171] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Recent studies indicate the importance of the ubiquitin ligase Siah2 in control of more aggressive prostate tumors – namely, neuroendocrine (NE) prostate tumors and prostate adenocarcinoma (PCa) harboring neuroendocrine lesions. Siah2-dependent expression and activity of HIF-1α regulate its availability to form a transcriptional complex with FoxA2, resulting in expression of specific target genes, including Hes6, Sox9 and Jmjd1a, whose co-expression is sufficient for formation of NE tumors and NE lesions in PCa. These studies provide novel markers to diagnose and monitor formation of NE lesions and NE tumors. Furthermore, defining the regulatory axis consisting of Siah2 and HIF-1α/FoxA2 cooperation suggests novel therapeutic modalities to treat these most aggressive forms of prostate cancer. Here we review current understanding of Siah role in control of hypoxia and prostate tumor development and highlight potential approaches for targeting components along Siah-regulated pathways.
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Affiliation(s)
- Jianfei Qi
- Signal Transduction Program, Sanford-Burnham Medical Research Institute, La Jolla, CA 92037, USA
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299
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Miranda-Carboni GA, Guemes M, Bailey S, Anaya E, Corselli M, Peault B, Krum SA. GATA4 regulates estrogen receptor-alpha-mediated osteoblast transcription. Mol Endocrinol 2011; 25:1126-36. [PMID: 21566084 DOI: 10.1210/me.2010-0463] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Estrogens regulate osteoblast differentiation and mineralization. We identified GATA4 as a transcription factor expressed in osteoblasts and directly regulated by 17β-estradiol in this cell type but not in breast cancer cells, another estrogen-responsive tissue. Chromatin immunoprecipitation sequencing (chromatin immunoprecipitation sequencing) reveals that estrogen receptor α (ERα) binds to chromatin near GATA4 at five different enhancers. GATA4 and ERα are both recruited to ERα binding sites near genes that are specifically expressed in osteoblasts and control osteoblast differentiation. Maximal binding of GATA4 precedes ERα binding, and GATA4 is necessary for histone 3 lysine 4 dimethylation at ERα binding sites, suggesting that GATA4 is a pioneer factor for ERα. As such, knockdown of GATA4 reduced recruitment of ERα to DNA. Our study illustrates that GATA4 is a pioneer factor for ERα recruitment to osteoblast-specific enhancers.
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Affiliation(s)
- Gustavo A Miranda-Carboni
- Department of Obstetrics and Gynecology, Jonsson Comprehensive Cancer Center, University of California, Los Angeles, David Geffen School of Medicine at UCLA, Los Angeles, California 90095, USA
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300
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Yu KS, Jo JY, Kim SJ, Lee Y, Bae JH, Chung YH, Koh SS. Epigenetic regulation of the transcription factor Foxa2 directs differential elafin expression in melanocytes and melanoma cells. Biochem Biophys Res Commun 2011; 408:160-6. [DOI: 10.1016/j.bbrc.2011.04.001] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2011] [Accepted: 04/01/2011] [Indexed: 11/30/2022]
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