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Raghuwanshi S, Gartel AL. Small-molecule inhibitors targeting FOXM1: Current challenges and future perspectives in cancer treatments. Biochim Biophys Acta Rev Cancer 2023; 1878:189015. [PMID: 37913940 DOI: 10.1016/j.bbcan.2023.189015] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2023] [Revised: 10/26/2023] [Accepted: 10/27/2023] [Indexed: 11/03/2023]
Abstract
Forkhead box (FOX) protein M1 (FOXM1) is a critical proliferation-associated transcription factor (TF) that is aberrantly overexpressed in the majority of human cancers and has also been implicated in poor prognosis. A comprehensive understanding of various aspects of this molecule has revealed its role in, cell proliferation, cell migration, invasion, angiogenesis and metastasis. The FOXM1 as a TF directly or indirectly regulates the expression of several target genes whose dysregulation is associated with almost all hallmarks of cancer. Moreover, FOXM1 expression is associated with chemoresistance to different anti-cancer drugs. Several studies have confirmed that suppression of FOXM1 enhanced the drug sensitivity of various types of cancer cells. Current data suggest that small molecule inhibitors targeting FOXM1 in combination with anticancer drugs may represent a novel therapeutic strategy for chemo-resistant cancers. In this review, we discuss the clinical utility of FOXM1, further, we summarize and discuss small-molecule inhibitors targeting FOXM1 and categorize them according to their mechanisms of targeting FOXM1. Despite great progress, small-molecule inhibitors targeting FOXM1 face many challenges, and we present here all small-molecule FOXM1 inhibitors in different stages of development. We discuss the current challenges and provide insights on the future application of FOXM1 inhibition to the clinic.
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Affiliation(s)
- Sanjeev Raghuwanshi
- University of Illinois at Chicago, Department of Medicine, Chicago, IL 60612, USA
| | - Andrei L Gartel
- University of Illinois at Chicago, Department of Medicine, Chicago, IL 60612, USA.
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2
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Liu C, Barger CJ, Karpf AR. FOXM1: A Multifunctional Oncoprotein and Emerging Therapeutic Target in Ovarian Cancer. Cancers (Basel) 2021; 13:3065. [PMID: 34205406 PMCID: PMC8235333 DOI: 10.3390/cancers13123065] [Citation(s) in RCA: 33] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2021] [Revised: 06/11/2021] [Accepted: 06/16/2021] [Indexed: 02/08/2023] Open
Abstract
Forkhead box M1 (FOXM1) is a member of the conserved forkhead box (FOX) transcription factor family. Over the last two decades, FOXM1 has emerged as a multifunctional oncoprotein and a robust biomarker of poor prognosis in many human malignancies. In this review article, we address the current knowledge regarding the mechanisms of regulation and oncogenic functions of FOXM1, particularly in the context of ovarian cancer. FOXM1 and its associated oncogenic transcriptional signature are enriched in >85% of ovarian cancer cases and FOXM1 expression and activity can be enhanced by a plethora of genomic, transcriptional, post-transcriptional, and post-translational mechanisms. As a master transcriptional regulator, FOXM1 promotes critical oncogenic phenotypes in ovarian cancer, including: (1) cell proliferation, (2) invasion and metastasis, (3) chemotherapy resistance, (4) cancer stem cell (CSC) properties, (5) genomic instability, and (6) altered cellular metabolism. We additionally discuss the evidence for FOXM1 as a cancer biomarker, describe the rationale for FOXM1 as a cancer therapeutic target, and provide an overview of therapeutic strategies used to target FOXM1 for cancer treatment.
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Affiliation(s)
| | | | - Adam R. Karpf
- Eppley Institute and Fred & Pamela Buffett Cancer Center, University of Nebraska Medical Center, Omaha, NE 68918-6805, USA; (C.L.); (C.J.B.)
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3
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Sayama Y, Sano M, Kaneko MK, Kato Y. Epitope Analysis of an Anti-Whale Podoplanin Monoclonal Antibody, PMab-237, Using Flow Cytometry. Monoclon Antib Immunodiagn Immunother 2020; 39:17-22. [PMID: 31934820 PMCID: PMC7044787 DOI: 10.1089/mab.2019.0045] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Podoplanin (PDPN) is a small mucin-type transmembrane glycoprotein, which was first discovered in podocytes of the kidney. PDPN is a specific lymphatic endothelial marker and is also known as T1alpha, a marker of lung type I alveolar cells, or Aggrus, a platelet aggregation-inducing factor. PDPN possesses three platelet aggregation-stimulating (PLAG) domains and PLAG-like domains (PLDs), which bind to C-type lectin-like receptor-2. Previously, we developed a novel anti-whale PDPN (wPDPN) monoclonal antibody (mAb) PMab-237 using the Cell-Based Immunization and Screening (CBIS) method and the RIEDL tag of Arg-Ile-Glu-Asp-Leu sequence. PMab-237 detected wPDPN by flow cytometry, western blot, and immunohistochemical analyses. However, the specific binding epitope of PMab-237 for wPDPN remains unknown. In this study, deletion mutants and point mutants of wPDPN with N-terminal RIEDL tag were produced to analyze the PMab-237 epitope using flow cytometry. The analysis of deletion mutants showed that the N-terminus of the PMab-237 epitope exists between the 80th amino acid (AA) and the 85th AA of wPDPN. In addition, the analysis of point mutants demonstrated that the critical epitope of PMab-237 includes Leu82 and Thr84 of wPDPN, indicating that the PMab-237 epitope is located in the PLD of wPDPN.
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Affiliation(s)
- Yusuke Sayama
- Department of Antibody Drug Development, Tohoku University Graduate School of Medicine, Sendai, Japan
| | - Masato Sano
- Department of Antibody Drug Development, Tohoku University Graduate School of Medicine, Sendai, Japan
| | - Mika K Kaneko
- Department of Antibody Drug Development, Tohoku University Graduate School of Medicine, Sendai, Japan
| | - Yukinari Kato
- Department of Antibody Drug Development, Tohoku University Graduate School of Medicine, Sendai, Japan.,New Industry Creation Hatchery Center, Tohoku University, Sendai, Japan
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4
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Moisés J, Navarro A, Santasusagna S, Viñolas N, Molins L, Ramirez J, Osorio J, Saco A, Castellano JJ, Muñoz C, Morales S, Monzó M, Marrades RM. NKX2-1 expression as a prognostic marker in early-stage non-small-cell lung cancer. BMC Pulm Med 2017; 17:197. [PMID: 29237428 PMCID: PMC5727907 DOI: 10.1186/s12890-017-0542-z] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2017] [Accepted: 11/29/2017] [Indexed: 12/11/2022] Open
Abstract
BACKGROUND NKX2-1, a key molecule in lung development, is highly expressed in non-small cell lung cancer (NSCLC), particularly in lung adenocarcinoma (ADK), where it is a diagnostic marker. Studies of the prognostic role of NKX2-1 in NSCLC have reported contradictory findings. Two microRNAs (miRNAs) have been associated with NKX2-1: miR-365, which targets NKX2-1; and miR-33a, which is downstream of NKX2-1. We have examined the effect of NKX2-1, miR-365 and miR-33a on survival in a cohort of early-stage NSCLC patients and in sub-groups of patients classified according to the mutational status of TP53, KRAS, and EGFR. METHODS mRNA and miRNA expression was determined using TaqMan assays in 110 early-stage NSCLC patients. TP53, KRAS, and EGFR mutations were assessed by Sanger sequencing. RESULTS NKX2-1 expression was upregulated in never-smokers (P = 0.017), ADK (P < 0.0001) and patients with wild-type TP53 (P = 0.001). A negative correlation between NKX2-1 and miR-365 expression was found (ρ = -0.287; P = 0.003) but there was no correlation between NKX2-1 and miR-33a expression. Overall survival (OS) was longer in patients with high expression of NKX2-1 than in those with low expression (80.8 vs 61.2 months (P = 0.035), while a trend towards longer OS was observed in patients with low miR-365 levels (P = 0.07). The impact of NKX2-1 on OS and DFS was higher in patients with neither TP53 nor KRAS mutations. Higher expression of NKX2-1 was related to higher OS (77.6 vs 54 months; P = 0.017) and DFS (74.6 vs 57.7 months; P = 0.006) compared to low expression. The association between NKX2-1 and OS and DFS was strengthened when the analysis was limited to patients with stage I disease (P = 0.005 and P=0.003 respectively). CONCLUSIONS NKX2-1 expression impacts prognosis in early-stage NSCLC patients, particularly in those with neither TP53 nor KRAS mutations.
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Affiliation(s)
- Jorge Moisés
- Department of Pneumology, Institut Clínic Respiratori (ICR), Hospital Clínic de Barcelona, University of Barcelona, IDIBAPS, CIBER de Enfermedades Respiratorias (CIBERES), Barcelona, Spain
| | - Alfons Navarro
- Molecular Oncology and Embryology Laboratory, Human Anatomy Unit, School of Medicine, University of Barcelona, IDIBAPS, Casanova 143, 08036 Barcelona, Spain
| | - Sandra Santasusagna
- Molecular Oncology and Embryology Laboratory, Human Anatomy Unit, School of Medicine, University of Barcelona, IDIBAPS, Casanova 143, 08036 Barcelona, Spain
| | - Nuria Viñolas
- Department of Medical Oncology, Institut Clínic de Malalties Hematològicas i Oncològiques (ICMHO), Hospital Clínic de Barcelona, University of Barcelona, IDIBAPS, Barcelona, Spain
| | - Laureano Molins
- Department of Thoracic Surgery, Institut Clínic Respiratori (ICT), Hospital Clínic de Barcelona, University of Barcelona, Barcelona, Spain
| | - José Ramirez
- Department of Pathology, Centre de Diagnòstic Biomèdic (CDB), Hospital Clínic de Barcelona, University of Barcelona, IDIBAPS, CIBERES, Barcelona, Spain
| | - Jeisson Osorio
- Department of Pneumology, Institut Clínic Respiratori (ICR), Hospital Clínic de Barcelona, University of Barcelona, IDIBAPS, CIBER de Enfermedades Respiratorias (CIBERES), Barcelona, Spain
| | - Adela Saco
- Department of Pathology, Centre de Diagnòstic Biomèdic (CDB), Hospital Clínic de Barcelona, University of Barcelona, IDIBAPS, CIBERES, Barcelona, Spain
| | - Joan Josep Castellano
- Molecular Oncology and Embryology Laboratory, Human Anatomy Unit, School of Medicine, University of Barcelona, IDIBAPS, Casanova 143, 08036 Barcelona, Spain
| | - Carmen Muñoz
- Molecular Oncology and Embryology Laboratory, Human Anatomy Unit, School of Medicine, University of Barcelona, IDIBAPS, Casanova 143, 08036 Barcelona, Spain
| | - Sara Morales
- Molecular Oncology and Embryology Laboratory, Human Anatomy Unit, School of Medicine, University of Barcelona, IDIBAPS, Casanova 143, 08036 Barcelona, Spain
| | - Mariano Monzó
- Molecular Oncology and Embryology Laboratory, Human Anatomy Unit, School of Medicine, University of Barcelona, IDIBAPS, Casanova 143, 08036 Barcelona, Spain
| | - Ramón María Marrades
- Department of Pneumology, Institut Clínic Respiratori (ICR), Hospital Clínic de Barcelona, University of Barcelona, IDIBAPS, CIBER de Enfermedades Respiratorias (CIBERES), Barcelona, Spain
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5
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Marconett CN, Zhou B, Sunohara M, Pouldar TM, Wang H, Liu Y, Rieger ME, Tran E, Flodby P, Siegmund KD, Crandall ED, Laird-Offringa IA, Borok Z. Cross-Species Transcriptome Profiling Identifies New Alveolar Epithelial Type I Cell-Specific Genes. Am J Respir Cell Mol Biol 2017; 56:310-321. [PMID: 27749084 DOI: 10.1165/rcmb.2016-0071oc] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Diseases involving the distal lung alveolar epithelium include chronic obstructive pulmonary disease, idiopathic pulmonary fibrosis, and lung adenocarcinoma. Accurate labeling of specific cell types is critical for determining the contribution of each to the pathogenesis of these diseases. The distal lung alveolar epithelium is composed of two cell types, alveolar epithelial type 1 (AT1) and type 2 (AT2) cells. Although cell type-specific markers, most prominently surfactant protein C, have allowed detailed lineage tracing studies of AT2 cell differentiation and the cells' roles in disease, studies of AT1 cells have been hampered by a lack of genes with expression unique to AT1 cells. In this study, we performed genome-wide expression profiling of multiple rat organs together with purified rat AT2, AT1, and in vitro differentiated AT1-like cells, resulting in the identification of 54 candidate AT1 cell markers. Cross-referencing with genes up-regulated in human in vitro differentiated AT1-like cells narrowed the potential list to 18 candidate genes. Testing the top four candidate genes at RNA and protein levels revealed GRAM domain 2 (GRAMD2), a protein of unknown function, as highly specific to AT1 cells. RNA sequencing (RNAseq) confirmed that GRAMD2 is transcriptionally silent in human AT2 cells. Immunofluorescence verified that GRAMD2 expression is restricted to the plasma membrane of AT1 cells and is not expressed in bronchial epithelial cells, whereas reverse transcription-polymerase chain reaction confirmed that it is not expressed in endothelial cells. Using GRAMD2 as a new AT1 cell-specific gene will enhance AT1 cell isolation, the investigation of alveolar epithelial cell differentiation potential, and the contribution of AT1 cells to distal lung diseases.
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Affiliation(s)
- Crystal N Marconett
- Departments of 1 Surgery and.,2 Biochemistry and Molecular Medicine.,3 Norris Comprehensive Cancer Center
| | - Beiyun Zhou
- 3 Norris Comprehensive Cancer Center.,4 Department of Medicine, Will Rogers Institute Pulmonary Research Center, Division of Pulmonary, Critical Care and Sleep Medicine, and
| | - Mitsuhiro Sunohara
- 4 Department of Medicine, Will Rogers Institute Pulmonary Research Center, Division of Pulmonary, Critical Care and Sleep Medicine, and
| | | | - Hongjun Wang
- 4 Department of Medicine, Will Rogers Institute Pulmonary Research Center, Division of Pulmonary, Critical Care and Sleep Medicine, and
| | - Yixin Liu
- 4 Department of Medicine, Will Rogers Institute Pulmonary Research Center, Division of Pulmonary, Critical Care and Sleep Medicine, and
| | - Megan E Rieger
- 4 Department of Medicine, Will Rogers Institute Pulmonary Research Center, Division of Pulmonary, Critical Care and Sleep Medicine, and
| | - Evelyn Tran
- Departments of 1 Surgery and.,2 Biochemistry and Molecular Medicine.,3 Norris Comprehensive Cancer Center
| | - Per Flodby
- 4 Department of Medicine, Will Rogers Institute Pulmonary Research Center, Division of Pulmonary, Critical Care and Sleep Medicine, and
| | - Kimberly D Siegmund
- 5 Department of Preventive Medicine, Keck School of Medicine, University of Southern California, Los Angeles, California
| | - Edward D Crandall
- 4 Department of Medicine, Will Rogers Institute Pulmonary Research Center, Division of Pulmonary, Critical Care and Sleep Medicine, and
| | - Ite A Laird-Offringa
- Departments of 1 Surgery and.,2 Biochemistry and Molecular Medicine.,3 Norris Comprehensive Cancer Center
| | - Zea Borok
- 2 Biochemistry and Molecular Medicine.,3 Norris Comprehensive Cancer Center.,4 Department of Medicine, Will Rogers Institute Pulmonary Research Center, Division of Pulmonary, Critical Care and Sleep Medicine, and
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6
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Baarsma HA, Skronska-Wasek W, Mutze K, Ciolek F, Wagner DE, John-Schuster G, Heinzelmann K, Günther A, Bracke KR, Dagouassat M, Boczkowski J, Brusselle GG, Smits R, Eickelberg O, Yildirim AÖ, Königshoff M. Noncanonical WNT-5A signaling impairs endogenous lung repair in COPD. J Exp Med 2016; 214:143-163. [PMID: 27979969 PMCID: PMC5206496 DOI: 10.1084/jem.20160675] [Citation(s) in RCA: 107] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2016] [Revised: 09/16/2016] [Accepted: 11/04/2016] [Indexed: 01/17/2023] Open
Abstract
Chronic obstructive pulmonary disease (COPD) is a leading cause of death worldwide. One main pathological feature of COPD is the loss of functional alveolar tissue without adequate repair (emphysema), yet the underlying mechanisms are poorly defined. Reduced WNT-β-catenin signaling is linked to impaired lung repair in COPD; however, the factors responsible for attenuating this pathway remain to be elucidated. Here, we identify a canonical to noncanonical WNT signaling shift contributing to COPD pathogenesis. We demonstrate enhanced expression of noncanonical WNT-5A in two experimental models of COPD and increased posttranslationally modified WNT-5A in human COPD tissue specimens. WNT-5A was increased in primary lung fibroblasts from COPD patients and induced by COPD-related stimuli, such as TGF-β, cigarette smoke (CS), and cellular senescence. Functionally, mature WNT-5A attenuated canonical WNT-driven alveolar epithelial cell wound healing and transdifferentiation in vitro. Lung-specific WNT-5A overexpression exacerbated airspace enlargement in elastase-induced emphysema in vivo. Accordingly, inhibition of WNT-5A in vivo attenuated lung tissue destruction, improved lung function, and restored expression of β-catenin-driven target genes and alveolar epithelial cell markers in the elastase, as well as in CS-induced models of COPD. We thus identify a novel essential mechanism involved in impaired mesenchymal-epithelial cross talk in COPD pathogenesis, which is amenable to therapy.
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Affiliation(s)
- Hoeke A Baarsma
- Comprehensive Pneumology Center, Research Unit Lung Repair and Regeneration, Helmholtz Center Munich, Ludwig Maximilians University Munich, University Hospital Grosshadern, 81377 Munich, Germany
| | - Wioletta Skronska-Wasek
- Comprehensive Pneumology Center, Research Unit Lung Repair and Regeneration, Helmholtz Center Munich, Ludwig Maximilians University Munich, University Hospital Grosshadern, 81377 Munich, Germany
| | - Kathrin Mutze
- Comprehensive Pneumology Center, Research Unit Lung Repair and Regeneration, Helmholtz Center Munich, Ludwig Maximilians University Munich, University Hospital Grosshadern, 81377 Munich, Germany
| | - Florian Ciolek
- Comprehensive Pneumology Center, Research Unit Lung Repair and Regeneration, Helmholtz Center Munich, Ludwig Maximilians University Munich, University Hospital Grosshadern, 81377 Munich, Germany
| | - Darcy E Wagner
- Comprehensive Pneumology Center, Research Unit Lung Repair and Regeneration, Helmholtz Center Munich, Ludwig Maximilians University Munich, University Hospital Grosshadern, 81377 Munich, Germany
| | - Gerrit John-Schuster
- Comprehensive Pneumology Center, Research Unit Lung Repair and Regeneration, Helmholtz Center Munich, Ludwig Maximilians University Munich, University Hospital Grosshadern, 81377 Munich, Germany
| | - Katharina Heinzelmann
- Comprehensive Pneumology Center, Research Unit Lung Repair and Regeneration, Helmholtz Center Munich, Ludwig Maximilians University Munich, University Hospital Grosshadern, 81377 Munich, Germany
| | | | - Ken R Bracke
- Department of Respiratory Medicine, Ghent University Hospital, 9000 Ghent, Belgium
| | | | | | - Guy G Brusselle
- Department of Respiratory Medicine, Ghent University Hospital, 9000 Ghent, Belgium
| | - Ron Smits
- Department of Gastroenterology and Hepatology, Erasmus MC University Medical Center Rotterdam, 3000 Rotterdam, Netherlands
| | - Oliver Eickelberg
- Comprehensive Pneumology Center, Research Unit Lung Repair and Regeneration, Helmholtz Center Munich, Ludwig Maximilians University Munich, University Hospital Grosshadern, 81377 Munich, Germany
| | - Ali Ö Yildirim
- Comprehensive Pneumology Center, Research Unit Lung Repair and Regeneration, Helmholtz Center Munich, Ludwig Maximilians University Munich, University Hospital Grosshadern, 81377 Munich, Germany
| | - Melanie Königshoff
- Comprehensive Pneumology Center, Research Unit Lung Repair and Regeneration, Helmholtz Center Munich, Ludwig Maximilians University Munich, University Hospital Grosshadern, 81377 Munich, Germany
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7
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Gottfried L, Lin X, Barravecchia M, Dean DA. Identification of an alveolar type I epithelial cell-specific DNA nuclear import sequence for gene delivery. Gene Ther 2016; 23:734-742. [PMID: 27367840 PMCID: PMC10141512 DOI: 10.1038/gt.2016.52] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2016] [Revised: 04/27/2016] [Accepted: 06/20/2016] [Indexed: 11/09/2022]
Abstract
The ability to restrict gene delivery and expression to particular cell types is of paramount importance for many types of gene therapy, especially in the lung. The alveolar epithelial type I (ATI) cell, in particular, is an attractive cell type to target, as it comprises 95% of the internal surface area of the lung. We demonstrate, through microinjection of fluorescently labeled plasmids, that a DNA sequence within the rat T1α promoter was able to mediate ATI cell-specific plasmid DNA nuclear import due to the binding of ATI-enriched transcription factors. Promoter deletion analysis and site-directed mutagenesis of specific transcription-factor-binding sites within the +101 to -200 bp region of the T1α promoter identified HNF3 and TTF-1 as critical transcription factors for import. To test for nuclear import in vivo, plasmids expressing GFP from the CMV promoter were delivered into the lungs of mice by electroporation and evaluated immunohistochemically 48 h later. Plasmids carrying the 1.3 kbp T1α sequence resulted in GFP expression almost exclusively in ATI cells. This represents a new and highly efficient way to target a specific lung epithelial cell type both in vitro and in vivo based on the restriction of DNA nuclear import.
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Affiliation(s)
- L Gottfried
- Department of Pediatrics, School of Medicine and Dentistry, University of Rochester, Rochester, NY, USA
| | - X Lin
- Department of Pediatrics, School of Medicine and Dentistry, University of Rochester, Rochester, NY, USA
| | - M Barravecchia
- Department of Pediatrics, School of Medicine and Dentistry, University of Rochester, Rochester, NY, USA
| | - D A Dean
- Department of Pediatrics, School of Medicine and Dentistry, University of Rochester, Rochester, NY, USA
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8
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Renart J, Carrasco-Ramírez P, Fernández-Muñoz B, Martín-Villar E, Montero L, Yurrita MM, Quintanilla M. New insights into the role of podoplanin in epithelial-mesenchymal transition. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2015; 317:185-239. [PMID: 26008786 DOI: 10.1016/bs.ircmb.2015.01.009] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Podoplanin is a small mucin-like transmembrane protein expressed in several adult tissues and with an important role during embryogenesis. It is needed for the proper development of kidneys and lungs as well as accurate formation of the lymphatic vascular system. In addition, it is involved in the physiology of the immune system. A wide variety of tumors express podoplanin, both in the malignant cells and in the stroma. Although there are exceptions, the presence of podoplanin results in poor prognosis. The main consequence of forced podoplanin expression in established and tumor-derived cell lines is an increase in cell migration and, eventually, the triggering of an epithelial-mesenchymal transition, whereby cells acquire a fibroblastoid phenotype and increased motility. We will examine the current status of the role of podoplanin in the induction of epithelial-mesenchymal transition as well as the different interactions that lead to this program.
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Affiliation(s)
- Jaime Renart
- Instituto de Investigaciones Biomédicas Alberto Sols, CSIC-UAM, Madrid, Spain
| | | | | | - Ester Martín-Villar
- Instituto de Investigaciones Biomédicas Alberto Sols, CSIC-UAM, Madrid, Spain
| | - Lucía Montero
- Instituto de Investigaciones Biomédicas Alberto Sols, CSIC-UAM, Madrid, Spain
| | - María M Yurrita
- Instituto de Investigaciones Biomédicas Alberto Sols, CSIC-UAM, Madrid, Spain
| | - Miguel Quintanilla
- Instituto de Investigaciones Biomédicas Alberto Sols, CSIC-UAM, Madrid, Spain
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9
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Yamaguchi T, Hosono Y, Yanagisawa K, Takahashi T. NKX2-1/TTF-1: an enigmatic oncogene that functions as a double-edged sword for cancer cell survival and progression. Cancer Cell 2013; 23:718-23. [PMID: 23763999 DOI: 10.1016/j.ccr.2013.04.002] [Citation(s) in RCA: 113] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/17/2012] [Revised: 02/19/2013] [Accepted: 04/01/2013] [Indexed: 01/30/2023]
Abstract
Emerging evidence indicates that NKX2-1, a homeobox-containing transcription factor also known as TTF-1, plays a role as a "lineage-survival" oncogene in lung adenocarcinomas. In T cell acute lymphoblastic leukemia, gene rearrangements lead to aberrant expression of NKX2-1/TTF-1. Despite accumulating evidence supporting its oncogenic role, it has become apparent that NKX2-1/TTF-1 expression also has biological and clinical functions in the opposite direction that act against tumor progression. Herein, we review recent findings showing these enigmatic double-edged characteristics, with special attention given to the roles of NKX2-1/TTF-1 in lung development and carcinogenesis.
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Affiliation(s)
- Tomoya Yamaguchi
- Division of Molecular Carcinogenesis, Center for Neurological Diseases and Cancer, Nagoya University Graduate School of Medicine, Nagoya 466-8550, Japan
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10
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Varma S, Cao Y, Tagne JB, Lakshminarayanan M, Li J, Friedman TB, Morell RJ, Warburton D, Kotton DN, Ramirez MI. The transcription factors Grainyhead-like 2 and NK2-homeobox 1 form a regulatory loop that coordinates lung epithelial cell morphogenesis and differentiation. J Biol Chem 2012; 287:37282-95. [PMID: 22955271 DOI: 10.1074/jbc.m112.408401] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The Grainyhead family of transcription factors controls morphogenesis and differentiation of epithelial cell layers in multicellular organisms by regulating cell junction- and proliferation-related genes. Grainyhead-like 2 (Grhl2) is expressed in developing mouse lung epithelium and is required for normal lung organogenesis. The specific epithelial cells expressing Grhl2 and the genes regulated by Grhl2 in normal lungs are mostly unknown. In these studies we identified the NK2-homeobox 1 transcription factor (Nkx2-1) as a direct transcriptional target of Grhl2. By binding and transcriptional assays and by confocal microscopy we showed that these two transcription factors form a positive feedback loop in vivo and in cell lines and are co-expressed in lung bronchiolar and alveolar type II cells. The morphological changes observed in flattening lung alveolar type II cells in culture are associated with down-regulation of Grhl2 and Nkx2-1. Reduction of Grhl2 in lung epithelial cell lines results in lower expression levels of Nkx2-1 and of known Grhl2 target genes. By microarray analysis we identified that in addition to Cadherin1 and Claudin4, Grhl2 regulates other cell interaction genes such as semaphorins and their receptors, which also play a functional role in developing lung epithelium. Impaired collective cell migration observed in Grhl2 knockdown cell monolayers is associated with reduced expression of these genes and may contribute to the altered epithelial phenotype reported in Grhl2 mutant mice. Thus, Grhl2 functions at the nexus of a novel regulatory network, connecting lung epithelial cell identity, migration, and cell-cell interactions.
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Affiliation(s)
- Saaket Varma
- Pulmonary Center, Department of Medicine, Boston University School of Medicine, Boston, Massachusetts 02118, USA
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11
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Tagne JB, Gupta S, Gower AC, Shen SS, Varma S, Lakshminarayanan M, Cao Y, Spira A, Volkert TL, Ramirez MI. Genome-wide analyses of Nkx2-1 binding to transcriptional target genes uncover novel regulatory patterns conserved in lung development and tumors. PLoS One 2012; 7:e29907. [PMID: 22242187 PMCID: PMC3252372 DOI: 10.1371/journal.pone.0029907] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2011] [Accepted: 12/07/2011] [Indexed: 01/10/2023] Open
Abstract
The homeodomain transcription factor Nkx2-1 is essential for normal lung development and homeostasis. In lung tumors, it is considered a lineage survival oncogene and prognostic factor depending on its expression levels. The target genes directly bound by Nkx2-1, that could be the primary effectors of its functions in the different cellular contexts where it is expressed, are mostly unknown. In embryonic day 11.5 (E11.5) mouse lung, epithelial cells expressing Nkx2-1 are predominantly expanding, and in E19.5 prenatal lungs, Nkx2-1-expressing cells are predominantly differentiating in preparation for birth. To evaluate Nkx2-1 regulated networks in these two cell contexts, we analyzed genome-wide binding of Nkx2-1 to DNA regulatory regions by chromatin immunoprecipitation followed by tiling array analysis, and intersected these data to expression data sets. We further determined expression patterns of Nkx2-1 developmental target genes in human lung tumors and correlated their expression levels to that of endogenous NKX2-1. In these studies we uncovered differential Nkx2-1 regulated networks in early and late lung development, and a direct function of Nkx2-1 in regulation of the cell cycle by controlling the expression of proliferation-related genes. New targets, validated in Nkx2-1 shRNA transduced cell lines, include E2f3, Cyclin B1, Cyclin B2, and c-Met. Expression levels of Nkx2-1 direct target genes identified in mouse development significantly correlate or anti-correlate to the levels of endogenous NKX2-1 in a dosage-dependent manner in multiple human lung tumor expression data sets, supporting alternative roles for Nkx2-1 as a transcriptional activator or repressor, and direct regulator of cell cycle progression in development and tumors.
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Affiliation(s)
- Jean-Bosco Tagne
- Pulmonary Center, Boston University School of Medicine, Boston, Massachusetts, United States of America
| | - Sumeet Gupta
- Center for Microarray Technology, Whitehead Institute for Biomedical Research, Cambridge, Massachusetts, United States of America
| | - Adam C. Gower
- Bioinformatics Program, Boston University, Boston, Massachusetts, United States of America
| | - Steven S. Shen
- Clinical and Translational Science Institute (CTSI), Boston University School of Medicine, Boston, Massachusetts, United States of America
| | - Saaket Varma
- Pulmonary Center, Boston University School of Medicine, Boston, Massachusetts, United States of America
| | | | - Yuxia Cao
- Pulmonary Center, Boston University School of Medicine, Boston, Massachusetts, United States of America
| | - Avrum Spira
- Bioinformatics Program, Boston University, Boston, Massachusetts, United States of America
- Clinical and Translational Science Institute (CTSI), Boston University School of Medicine, Boston, Massachusetts, United States of America
| | - Thomas L. Volkert
- Center for Microarray Technology, Whitehead Institute for Biomedical Research, Cambridge, Massachusetts, United States of America
| | - Maria I. Ramirez
- Pulmonary Center, Boston University School of Medicine, Boston, Massachusetts, United States of America
- * E-mail:
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12
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Das A, Acharya S, Gottipati KR, McKnight JB, Chandru H, Alcorn JL, Boggaram V. Thyroid transcription factor-1 (TTF-1) gene: identification of ZBP-89, Sp1, and TTF-1 sites in the promoter and regulation by TNF-α in lung epithelial cells. Am J Physiol Lung Cell Mol Physiol 2011; 301:L427-40. [PMID: 21784970 DOI: 10.1152/ajplung.00090.2011] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Thyroid transcription factor-1 (TTF-1/Nkx2.1/TITF1) is a homeodomain-containing transcription factor essential for the morphogenesis and differentiation of the lung. In the lung, TTF-1 controls the expression of surfactant proteins that are essential for lung stability and lung host defense. In this study, we identified functionally important transcription factor binding sites in the TTF-1 proximal promoter and studied tumor necrosis factor-α (TNF-α) regulation of TTF-1 expression. TNF-α, a proinflammatory cytokine, has been implicated in the pathogenesis of acute respiratory distress syndrome (ARDS) and inhibits surfactant protein levels. Deletion analysis of TTF-1 5'-flanking DNA indicated that the TTF-1 proximal promoter retained high-level activity. Electrophoretic mobility shift assay, chromatin immunoprecipitation, and mutational analysis experiments identified functional ZBP-89, Sp1, Sp3, and TTF-1 sites in the TTF-1 proximal promoter. TNF-α inhibited TTF-1 protein levels in H441 and primary alveolar type II cells. TNF-α inhibited TTF-1 gene transcription and promoter activity, indicating that transcriptional mechanisms play important roles in the inhibition of TTF-1 levels. TNF-α inhibited TTF-1 but not Sp1 or hepatocyte nuclear factor-3 DNA binding to TTF-1 promoter. Transactivation experiments in A549 cells indicated that TNF-α inhibited TTF-1 promoter activation by exogenous Sp1 and TTF-1 without altering their levels, suggesting inhibition of transcriptional activities of these proteins. TNF-α inhibition of TTF-1 expression was associated with increased threonine, but not serine, phosphorylation of Sp1. Because TTF-1 serves as a positive regulator for surfactant protein gene expression, TNF-α inhibition of TTF-1 expression could have important implications for the reduction of surfactant protein levels in diseases such as ARDS.
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Affiliation(s)
- Aparajita Das
- Center for Biomedical Research, The University of Texas Health Center at Tyler, 75708-3154, USA
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13
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Chen F, Cao Y, Qian J, Shao F, Niederreither K, Cardoso WV. A retinoic acid-dependent network in the foregut controls formation of the mouse lung primordium. J Clin Invest 2010; 120:2040-8. [PMID: 20484817 PMCID: PMC2877937 DOI: 10.1172/jci40253] [Citation(s) in RCA: 107] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2009] [Accepted: 03/24/2010] [Indexed: 12/14/2022] Open
Abstract
The developmental abnormalities associated with disruption of signaling by retinoic acid (RA), the biologically active form of vitamin A, have been known for decades from studies in animal models and humans. These include defects in the respiratory system, such as lung hypoplasia and agenesis. However, the molecular events controlled by RA that lead to formation of the lung primordium from the primitive foregut remain unclear. Here, we present evidence that endogenous RA acts as a major regulatory signal integrating Wnt and Tgfbeta pathways in the control of Fgf10 expression during induction of the mouse primordial lung. We demonstrated that activation of Wnt signaling required for lung formation was dependent on local repression of its antagonist, Dickkopf homolog 1 (Dkk1), by endogenous RA. Moreover, we showed that simultaneously activating Wnt and repressing Tgfbeta allowed induction of both lung buds in RA-deficient foreguts. The data in this study suggest that disruption of Wnt/Tgfbeta/Fgf10 interactions represents the molecular basis for the classically reported failure to form lung buds in vitamin A deficiency.
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Affiliation(s)
- Felicia Chen
- Pulmonary Center, Boston University School of Medicine, Boston, Massachusetts, USA.
Baylor College of Medicine, Houston, Texas, USA
| | - Yuxia Cao
- Pulmonary Center, Boston University School of Medicine, Boston, Massachusetts, USA.
Baylor College of Medicine, Houston, Texas, USA
| | - Jun Qian
- Pulmonary Center, Boston University School of Medicine, Boston, Massachusetts, USA.
Baylor College of Medicine, Houston, Texas, USA
| | - Fengzhi Shao
- Pulmonary Center, Boston University School of Medicine, Boston, Massachusetts, USA.
Baylor College of Medicine, Houston, Texas, USA
| | - Karen Niederreither
- Pulmonary Center, Boston University School of Medicine, Boston, Massachusetts, USA.
Baylor College of Medicine, Houston, Texas, USA
| | - Wellington V. Cardoso
- Pulmonary Center, Boston University School of Medicine, Boston, Massachusetts, USA.
Baylor College of Medicine, Houston, Texas, USA
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14
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Nuclear alpha NAC influences bone matrix mineralization and osteoblast maturation in vivo. Mol Cell Biol 2010; 30:43-53. [PMID: 19884350 DOI: 10.1128/mcb.00378-09] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Nascent-polypeptide-associated complex and coactivator alpha (alpha NAC) is a protein shuttling between the nucleus and the cytoplasm. Upon phosphorylation at residue serine 43 by integrin-linked kinase, alpha NAC is translocated to the nuclei of osteoblasts, where it acts as an AP-1 coactivator to increase osteocalcin gene transcription. To determine the physiological role of nuclear alpha NAC, we engineered a knock-in mouse model with a serine-to-alanine mutation at position 43 (S43A). The S43A mutation resulted in a decrease in the amount of nuclear alpha NAC with reduced osteocalcin gene promoter occupancy, leading to a significant decrease in osteocalcin gene transcription. The S43A mutant bones also expressed decreased levels of alpha(1)(I) collagen mRNA and as a consequence had significantly less osteoid tissue. Transient transfection assays and chromatin immunoprecipitation confirmed the alpha(1)(I) collagen gene as a novel alpha NAC target. The reduced quantity of bone matrix in S43A mutant bones was mineralized faster, as demonstrated by the significantly reduced mineralization lag time, producing a lower volume of immature, woven-type bone characterized by poor lamellation and an increase in the number of osteocytes. Accordingly, the expression of the osteocyte differentiation marker genes DMP-1 (dentin matrix protein 1), E11, and SOST (sclerostin) was increased. The accelerated mineralization phenotype was cell autonomous, as osteoblasts isolated from the calvaria of S43A mutant mice mineralized their matrix faster than did wild-type cells. Thus, inhibition of alpha NAC nuclear translocation results in an osteopenic phenotype caused by reduced expression of osteocalcin and type I collagen, accelerated mineralization, and immature woven-bone formation.
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15
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Warburton D, El-Hashash A, Carraro G, Tiozzo C, Sala F, Rogers O, De Langhe S, Kemp PJ, Riccardi D, Torday J, Bellusci S, Shi W, Lubkin SR, Jesudason E. Lung organogenesis. Curr Top Dev Biol 2010; 90:73-158. [PMID: 20691848 DOI: 10.1016/s0070-2153(10)90003-3] [Citation(s) in RCA: 290] [Impact Index Per Article: 20.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Developmental lung biology is a field that has the potential for significant human impact: lung disease at the extremes of age continues to cause major morbidity and mortality worldwide. Understanding how the lung develops holds the promise that investigators can use this knowledge to aid lung repair and regeneration. In the decade since the "molecular embryology" of the lung was first comprehensively reviewed, new challenges have emerged-and it is on these that we focus the current review. Firstly, there is a critical need to understand the progenitor cell biology of the lung in order to exploit the potential of stem cells for the treatment of lung disease. Secondly, the current familiar descriptions of lung morphogenesis governed by growth and transcription factors need to be elaborated upon with the reinclusion and reconsideration of other factors, such as mechanics, in lung growth. Thirdly, efforts to parse the finer detail of lung bud signaling may need to be combined with broader consideration of overarching mechanisms that may be therapeutically easier to target: in this arena, we advance the proposal that looking at the lung in general (and branching in particular) in terms of clocks may yield unexpected benefits.
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Affiliation(s)
- David Warburton
- The Saban Research Institute, Childrens Hospital Los Angeles, Los Angeles, California, USA
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16
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Flozak AS, Lam AP, Russell S, Jain M, Peled ON, Sheppard KA, Beri R, Mutlu GM, Budinger GRS, Gottardi CJ. Beta-catenin/T-cell factor signaling is activated during lung injury and promotes the survival and migration of alveolar epithelial cells. J Biol Chem 2009; 285:3157-67. [PMID: 19933277 DOI: 10.1074/jbc.m109.070326] [Citation(s) in RCA: 95] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
The Wnt/beta-catenin signaling cascade activates genes that allow cells to adopt particular identities throughout development. In adult self-renewing tissues like intestine and blood, activation of the Wnt pathway maintains a progenitor phenotype, whereas forced inhibition of this pathway promotes differentiation. In the lung alveolus, type 2 epithelial cells (AT2) have been described as progenitors for the type 1 cell (AT1), but whether AT2 progenitors use the same signaling mechanisms to control differentiation as rapidly renewing tissues is not known. We show that adult AT2 cells do not exhibit constitutive beta-catenin signaling in vivo, using the AXIN2(+/LacZ) reporter mouse, or after fresh isolation of an enriched population of AT2 cells. Rather, this pathway is activated in lungs subjected to bleomycin-induced injury, as well as upon placement of AT2 cells in culture. Forced inhibition of beta-catenin/T-cell factor signaling in AT2 cultures leads to increased cell death. Cells that survive show reduced migration after wounding and reduced expression of AT1 cell markers (T1alpha and RAGE). These results suggest that AT2 cells may function as facultative progenitors, where activation of Wnt/beta-catenin signaling during lung injury promotes alveolar epithelial survival, migration, and differentiation toward an AT1-like phenotype.
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Affiliation(s)
- Annette S Flozak
- Department of Medicine, Division of Pulmonary and Critical Care, Northwestern University Feinberg School of Medicine, Chicago, Illinois 60611, USA
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17
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Cao Y, Vo T, Millien G, Tagne JB, Kotton D, Mason RJ, Williams MC, Ramirez MI. Epigenetic mechanisms modulate thyroid transcription factor 1-mediated transcription of the surfactant protein B gene. J Biol Chem 2009; 285:2152-64. [PMID: 19906647 DOI: 10.1074/jbc.m109.039172] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Epigenetic regulation of transcription plays an important role in cell-specific gene expression by altering chromatin structure and access of transcriptional regulators to DNA binding sites. Surfactant protein B (Sftpb) is a developmentally regulated lung epithelial gene critical for lung function. Thyroid transcription factor 1 (Nkx2-1) regulates Sftpb gene expression in various species. We show that Nkx2-1 binds to the mouse Sftpb (mSftpb) promoter in the lung. In a mouse lung epithelial cell line (MLE-15), Nkx2-1 knockdown reduces Sftpb expression, and mutation of Nkx2-1 cis-elements significantly reduces mSftpb promoter activity. Whether chromatin structure modulates Nkx2-1 regulation of Sftpb transcription is unknown. We found that DNA methylation of the mSftpb promoter inversely correlates with known patterns of Sftpb expression in vivo. The mSftpb promoter activity can be manipulated by altering its cytosine methylation status in vitro. Nkx2-1 activation of the mSftpb promoter is impaired by DNA methylation. The unmethylated Sftpb promoter shows an active chromatin structure enriched in the histone modification H3K4me3 (histone 3-lysine 4 trimethylated). The ATP-dependent chromatin remodeling protein Brg1 is recruited to the Sftpb promoter in Sftpb-expressing, but not in non-expressing tissues and cell lines. Brg1 knockdown in MLE-15 cells greatly decreases H3K4me3 levels at the Sftpb promoter region and expression of the Sftpb gene. Brg1 can be co-immunoprecipitated with Nkx2-1 protein. Last, Nkx2-1 and Brg1 with intact ATPase activity are required for mSftpb promoter activation in vitro. Our findings suggest that DNA methylation and chromatin modifications cooperate with Nkx2-1 to regulate Sftpb gene cell specific expression.
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Affiliation(s)
- Yuxia Cao
- Pulmonary Center, Department of Medicine, Boston University School of Medicine, Boston, Massachusetts 02118, USA.
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18
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Reclassificação do carcinoma broncopulmonar: Diferenciação do tipo histológico em biópsias por imuno-histoquímica. REVISTA PORTUGUESA DE PNEUMOLOGIA 2009. [DOI: 10.1016/s0873-2159(15)30195-1] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
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19
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Thyroid transcription factor-1 (TTF-1/Nkx2.1/TITF1) gene regulation in the lung. Clin Sci (Lond) 2009; 116:27-35. [PMID: 19037882 DOI: 10.1042/cs20080068] [Citation(s) in RCA: 131] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
TTF-1 [thyroid transcription factor-1; also known as Nkx2.1, T/EBP (thyroid-specific-enhancer-binding protein) or TITF1] is a homeodomain-containing transcription factor essential for the morphogenesis and differentiation of the thyroid, lung and ventral forebrain. TTF-1 controls the expression of select genes in the thyroid, lung and the central nervous system. In the lung, TTF-1 controls the expression of surfactant proteins that are essential for lung stability and lung host defence. Human TTF-1 is encoded by a single gene located on chromosome 14 and is organized into two/three exons and one/two introns. Multiple transcription start sites and alternative splicing produce mRNAs with heterogeneity at the 5' end. The 3' end of the TTF-1 mRNA is characterized by a rather long untranslated region. The amino acid sequences of TTF-1 from human, rat, mouse and other species are very similar, indicating a high degree of sequence conservation. TTF-1 promoter activity is maintained by the combinatorial or co-operative actions of HNF-3 [hepatocyte nuclear factor-3; also known as FOXA (forkhead box A)], Sp (specificity protein) 1, Sp3, GATA-6 and HOXB3 (homeobox B3) transcription factors. There is limited information on the regulation of TTF-1 gene expression by hormones, cytokines and other biological agents. Glucocorticoids, cAMP and TGF-beta (transforming growth factor-beta) have stimulatory effects on TTF-1 expression, whereas TNF-alpha (tumour necrosis factor-alpha) and ceramide have inhibitory effects on TTF-1 DNA-binding activity in lung cells. Haplo-insufficiency of TTF-1 in humans causes hypothyroidism, respiratory dysfunction and recurring pulmonary infections, underlining the importance of optimal TTF-1 levels for the maintenance of thyroid and lung function. Recent studies have implicated TTF-1 as a lineage-specific proto-oncogene for lung cancer.
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20
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Kulkarni RM, Greenberg JM, Akeson AL. NFATc1 regulates lymphatic endothelial development. Mech Dev 2009; 126:350-65. [PMID: 19233265 DOI: 10.1016/j.mod.2009.02.003] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2008] [Revised: 02/09/2009] [Accepted: 02/11/2009] [Indexed: 01/23/2023]
Abstract
NFATc1 transcription factor is critical for lineage selection in T-cell differentiation, cardiac valve morphogenesis and osteoclastogenesis. We identified a role for calcineurin-NFAT signaling in lymphatic development and patterning. NFATc1 was colocalized with lymphatic markers Prox-1, VEGFR-3 and podoplanin on cardinal vein as lymphatic endothelial cells (LEC) are specified and as they segregate into lymph sacs and mature lymphatics. In NFATc1 null mice, Prox-1, VEGFR-3 and podoplanin positive endothelial cells sprouted from the cardinal vein at E11.5, but poorly coalesced into lymph sacs. NFAT activation requires the phosphatase calcineurin. Embryos treated in utero with the calcineurin inhibitor cyclosporine-A showed cytoplasmic NFATc1, diminished podoplanin and FGFR-3 expression by the lymphatics and irregular patterning of the LEC sprouts coming off the jugular lymph sac, which suggests a role for calcineurin-NFAT signaling in lymphatic patterning. In a murine model of injury-induced lymphangiogenesis, NFATc1 was expressed on the neolymphatics induced by lung-specific overexpression of VEGF-A. Mice lacking the calcineurin Abeta regulatory subunit, with diminished nuclear NFAT, failed to respond to VEGF-A with increased lymphangiogenesis. In vitro, endogenous and VEGF-A-induced VEGFR-3 and podoplanin expression by human microvascular endothelial cells was reduced by siRNA to NFATc1, to levels comparable to reductions seen with siRNA to Prox-1. In reporter assays, NFATc1 activated lymphatic specific gene promoters. These results demonstrate the role of calcineurin-NFAT pathway in lymphangiogenesis and suggest that NFATc1 is the principle NFAT involved.
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Affiliation(s)
- Rishikesh M Kulkarni
- Division of Pulmonary Biology, MLC7009, Cincinnati Children's Hospital Research Foundation, Cincinnati, OH 45229, USA
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21
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Zhou B, Francis TA, Yang H, Tseng W, Zhong Q, Frenkel B, Morrisey EE, Ann DK, Minoo P, Crandall ED, Borok Z. GATA-6 mediates transcriptional activation of aquaporin-5 through interactions with Sp1. Am J Physiol Cell Physiol 2008; 295:C1141-50. [PMID: 18768929 DOI: 10.1152/ajpcell.00120.2008] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
We investigated mechanisms underlying GATA-6-mediated transcriptional activation of the alveolar epithelial type I cell-enriched gene aquaporin-5 (AQP5). GATA-6 expression increases in alveolar epithelial cells in primary culture, concurrent with upregulation of AQP5 and transition to a type I cell-like phenotype. Cotransfections in MLE-15 and NIH 3T3 cells demonstrated trans-activation by GATA-6 of a rat 1,716-bp-AQP5-luciferase (-1716-AQP5-Luc) reporter. Electrophoretic mobility shift assay and chromatin immunoprecipitation identified an interaction between GATA-6 and putative binding sites in the AQP5 promoter. However, mutation of these sites did not reduce GATA-6-mediated activation, implicating mechanisms in addition to direct binding of GATA-6 to DNA. A 5'-deletion construct, -358-AQP5-Luc, that does not encompass GATA motifs was still activated by GATA-6 by as much as 50% relative to -1716-AQP5-Luc. Internal deletion of the -358/-173 GC-rich domain, which includes several putative Sp1 consensus sites, reduced trans-activation by approximately 60%, suggesting importance of this region for GATA-mediated activity. -358-AQP5-Luc was similarly activated by both GATA-6 and a GATA DNA-binding defective mutant, whereas cotransfections in Schneider S2 cells demonstrated dose-dependent trans-activation of -358-AQP5-Luc by Sp1. Activation of -358-AQP5-Luc by GATA-6 was dramatically reduced by Sp1 small-interfering RNA, and -358-AQP5-Luc was activated synergistically by GATA-6 and Sp1 in NIH 3T3 cells. Furthermore, association between endogenous GATA-6 and Sp1 was demonstrated by coimmunoprecipitation. These results suggest that transcriptional activation of AQP5 by GATA-6 is mediated at least in part through cooperative interactions with Sp1 occurring at the proximal promoter.
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Affiliation(s)
- Beiyun Zhou
- Will Rogers Institute Pulmonary Research Center, Los Angeles, CA, USA
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22
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Vanderbilt JN, Allen L, Gonzalez RF, Tigue Z, Edmondson J, Ansaldi D, Gillespie AM, Dobbs LG. Directed expression of transgenes to alveolar type I cells in the mouse. Am J Respir Cell Mol Biol 2008; 39:253-62. [PMID: 18367724 PMCID: PMC2542444 DOI: 10.1165/rcmb.2008-0049oc] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2008] [Accepted: 03/07/2008] [Indexed: 01/27/2023] Open
Abstract
Podoplanin (RTI40, aggrus, T1alpha, hT1alpha-2, E11, PA2.26, RANDAM-2, gp36, gp38, gp40, OTS8) is a type I cell marker in rat lung. We show that a bacterial artificial chromosome vector containing the rat podoplanin gene (RTIbac) delivers a pattern of transgene expression in lung that is more restricted to mouse type I cells than that of the endogenous mouse podoplanin gene. RTIbac-transgenic mice expressed rat podoplanin in type I cells; type II cells, airways, and vascular endothelium were negative. A modified bacterial artificial chromosome containing internal ribosome entry site (IRES)-green fluorescent protein (GFP) sequences in the podoplanin 3'UTR expressed rat podoplanin and transgenic GFP in type I cells. RTIbac transgene expression was absent or reduced in pulmonary pleura, lymphatic endothelium, and putative lymphoid-associated stromal tissue, all of which contained abundant mouse podoplanin. Rat podoplanin mRNA levels in normal rat lung and RTIbac transgenic lung were 25-fold higher than in corresponding kidney and brain samples. On Western blots, transgenic rat and endogenous mouse podoplanin displayed very similar patterns of protein expression in various organs. Highest protein levels were observed in lung with 10- to 20-fold less in brain; there were low levels in thymus and kidney. Both GFP and rat podoplanin transgenes were expressed at extrapulmonary sites of endogenous mouse podoplanin gene expression, including choroid plexus, eye ciliary epithelium, and renal glomerulus. Because their pulmonary expression is more restricted than endogenous mouse podoplanin, RTIbac derivatives should be useful for mouse type I cell-specific transgene delivery.
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Affiliation(s)
- Jeff N Vanderbilt
- Cardiovascular Research Institute, University of California San Francisco, San Francisco, California 94118, USA.
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23
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Wiener RS, Cao YX, Hinds A, Ramirez MI, Williams MC. Angiotensin converting enzyme 2 is primarily epithelial and is developmentally regulated in the mouse lung. J Cell Biochem 2007; 101:1278-91. [PMID: 17340620 PMCID: PMC7166549 DOI: 10.1002/jcb.21248] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Angiotensin converting enzyme (ACE) 2 is a carboxypeptidase that shares 42% amino acid homology with ACE. Little is known about the regulation or pattern of expression of ACE2 in the mouse lung, including its definitive cellular distribution or developmental changes. Based on Northern blot and RT‐PCR data, we report two distinct transcripts of ACE2 in the mouse lung and kidney and describe a 5′ exon 1a previously unidentified in the mouse. Western blots show multiple isoforms of ACE2, with predominance of a 75–80 kDa protein in the mouse lung versus a 120 kDa form in the mouse kidney. Immunohistochemistry localizes ACE2 protein to Clara cells, type II cells, and endothelium and smooth muscle of small and medium vessels in the mouse lung. ACE2 mRNA levels peak at embryonic day 18.5 in the mouse lung, and immunostaining demonstrates protein primarily in the bronchiolar epithelium at that developmental time point. In murine cell lines ACE2 is strongly expressed in the Clara cell line mtCC, as opposed to the low mRNA expression detected in E10 (type I‐like alveolar epithelial cell line), MLE‐15 (type II alveolar epithelial cell line), MFLM‐4 (fetal pulmonary vasculature cell line), and BUMPT‐7 (renal proximal tubule cell line). In summary, murine pulmonary ACE2 appears to be primarily epithelial, is developmentally regulated, and has two transcripts that include a previously undescribed exon. J. Cell. Biochem. 101:1278–1291, 2007. © 2007 Wiley‐Liss, Inc.
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Affiliation(s)
- Renda Soylemez Wiener
- The Pulmonary Center, Department of Medicine, Boston University School of Medicine, Boston, Massachusetts 02118, USA.
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24
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Hantusch B, Kalt R, Krieger S, Puri C, Kerjaschki D. Sp1/Sp3 and DNA-methylation contribute to basal transcriptional activation of human podoplanin in MG63 versus Saos-2 osteoblastic cells. BMC Mol Biol 2007; 8:20. [PMID: 17343736 PMCID: PMC1828165 DOI: 10.1186/1471-2199-8-20] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2006] [Accepted: 03/07/2007] [Indexed: 12/31/2022] Open
Abstract
Background Podoplanin is a membrane mucin that, among a series of tissues, is expressed on late osteoblasts and osteocytes. Since recent findings have focussed on podoplanin's potential role as a tumour progression factor, we aimed at identifying regulatory elements conferring PDPN promoter activity. Here, we characterized the molecular mechanism controlling basal PDPN transcription in human osteoblast-like MG63 versus Saos-2 cells. Results We cloned and sequenced 2056 nucleotides from the 5'-flanking region of the PDPN gene and a computational search revealed that the TATA and CAAT box-lacking promoter possesses features of a growth-related gene, such as a GC-rich 5' region and the presence of multiple putative Sp1, AP-4 and NF-1 sites. Reporter gene assays demonstrated a functional promoter in MG63 cells exhibiting 30-fold more activity than in Saos-2 cells. In vitro DNase I footprinting revealed eight protected regions flanked by DNaseI hypersensitive sites within the region bp -728 to -39 present in MG63, but not in Saos-2 cells. Among these regions, mutation and supershift electrophoretic mobility shift assays (EMSA) identified four Sp1/Sp3 binding sites and two binding sites for yet unknown transcription factors. Deletion studies demonstrated the functional importance of two Sp1/Sp3 sites for PDPN promoter activity. Overexpression of Sp1 and Sp3 independently increased the stimulatory effect of the promoter and podoplanin mRNA levels in MG63 and Saos-2 cells. In SL2 cells, Sp3 functioned as a repressor, while Sp1 and Sp3 acted positively synergistic. Weak PDPN promoter activity of Saos-2 cells correlated with low Sp1/Sp3 nuclear levels, which was confirmed by Sp1/Sp3 chromatin immunoprecipitations in vivo. Moreover, methylation-sensitive Southern blot analyses and bisulfite sequencing detected strong methylation of CpG sites upstream of bp -464 in MG63 cells, but hypomethylation of these sites in Saos-2 cells. Concomitantly, treatment with the DNA methyltransferase inhibitor 5-azaCdR in combination with trichostatin A (TSA) downregulated podoplanin mRNA levels in MG63 cells, and region-specific in vitro methylation of the distal promoter suggested that DNA methylation rather enhanced than hindered PDPN transcription in both cell types. Conclusion These data establish that in human osteoblast-like MG63 cells, Sp1 and Sp3 stimulate basal PDPN transcription in a concerted, yet independent manner, whereas Saos-2 cells lack sufficient nuclear Sp protein amounts for transcriptional activation. Moreover, a highly methylated chromatin conformation of the distal promoter region confers cell-type specific podoplanin upregulation versus Saos-2 cells.
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Affiliation(s)
- Brigitte Hantusch
- Institute of Clinical Pathology, Medical University of Vienna, Währinger Gürtel 18-20, A-1090 Vienna, Austria
| | - Romana Kalt
- Institute of Clinical Pathology, Medical University of Vienna, Währinger Gürtel 18-20, A-1090 Vienna, Austria
| | - Sigurd Krieger
- Institute of Clinical Pathology, Medical University of Vienna, Währinger Gürtel 18-20, A-1090 Vienna, Austria
| | - Christina Puri
- Institute of Clinical Pathology, Medical University of Vienna, Währinger Gürtel 18-20, A-1090 Vienna, Austria
| | - Dontscho Kerjaschki
- Institute of Clinical Pathology, Medical University of Vienna, Währinger Gürtel 18-20, A-1090 Vienna, Austria
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Kolla V, Gonzales LW, Gonzales J, Wang P, Angampalli S, Feinstein SI, Ballard PL. Thyroid transcription factor in differentiating type II cells: regulation, isoforms, and target genes. Am J Respir Cell Mol Biol 2007; 36:213-25. [PMID: 16960125 PMCID: PMC1899316 DOI: 10.1165/rcmb.2006-0207oc] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2006] [Accepted: 08/18/2006] [Indexed: 11/24/2022] Open
Abstract
Thyroid transcription factor-1 (TTF-1, product of the Nkx2.1 gene) is essential for branching morphogenesis of the lung and enhances expression of surfactant proteins by alveolar type II cells. We investigated expression of two TTF-1 mRNA transcripts, generated by alternative start sites and coding for 42- and 46-kD protein isoforms in the mouse, during hormone-induced differentiation of human fetal lung type II cells in culture. Transcript for 42-kD TTF-1 was 20-fold more abundant than TTF-1(46) mRNA by RT-PCR. Only 42-kD protein was detected in lung cells, and its content increased during in vivo development and in response to in vitro glucocorticoid plus cAMP treatment. To examine TTF-1 target proteins, recombinant, phosphorylated TTF-1(42) was expressed in nuclei of cells by adenovirus transduction. By microarray analysis, 14 genes were comparably induced by recombinant TTF-1 (rTTF-1) and hormone treatment, and 9 additional hormone-responsive genes, including surfactant proteins-A/B/C, were partially induced by rTTF-1. The most highly (approximately 10-fold) TTF-1-induced genes were DC-LAMP (LAMP3) and CEACAM6 with induction confirmed by Western analysis and immunostaining. Treatment of cells with hormones plus small inhibitory RNA directed toward TTF-1 reduced TTF-1 content by approximately 50% and inhibited hormone induction of the 23 genes induced by rTTF-1. In addition, knockdown of TTF-1 inhibited 72 of 274 other genes induced by hormones. We conclude that 42-kD TTF-1 is required for induction of a subset of regulated genes during type II cell differentiation.
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Affiliation(s)
- Venkatadri Kolla
- Department of Pediatrics, Children's Hospital of Philadelphia, University of Pennsylvania School of Medicine, USA
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Nomura J, Hisatsune A, Miyata T, Isohama Y. The role of CpG methylation in cell type-specific expression of the aquaporin-5 gene. Biochem Biophys Res Commun 2006; 353:1017-22. [PMID: 17198683 DOI: 10.1016/j.bbrc.2006.12.126] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2006] [Accepted: 12/17/2006] [Indexed: 10/23/2022]
Abstract
Aquaporin-5 (AQP5) is expressed in a cell type-specific manner. Here, we show that the AQP5 gene is regulated by CpG methylation. The AQP5 promoter containing a putative CpG island was highly methylated in NIH-3T3 or freshly isolated alveolar epithelial cells, correlating with the repression of this gene in these cells. In contrast, the AQP5 promoter was hypo-methylated in MLE-12 or cultured alveolar epithelial cells, which express high levels of AQP5. Repression of AQP5 transcription in NIH-3T3 cells could be relieved with 5-azacytidine, and in vitro methylation of the AQP5 promoter resulted in inhibition of transcription of the reporter gene in MLE-12 cells. Chromatin immunoprecipitation assays showed that endogenous Sp1 bound to the hypo-methylated, but not highly methylated, AQP5 promoter region. These results demonstrate that the hypo-methylated state of the AQP5 promoter leading to increased Sp1 binding may play a role in regulation of cell type-specific expression of the AQP5 gene.
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Affiliation(s)
- Johji Nomura
- Department of Chemico-Pharmacological Sciences, Graduate School of Pharmaceutical Sciences, Kumamoto University, 5-1 Oe-honmachi, Kumamoto 862-0973, Japan
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27
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Abstract
Organized and coordinated lung development follows transcriptional regulation of a complex set of cell-cell and cell-matrix interactions resulting in a blood-gas interface ready for physiologic gas exchange at birth. Transcription factors, growth factors, and various other signaling molecules regulate epithelial-mesenchymal interactions by paracrine and autocrine mechanisms. Transcriptional control at the earliest stages of lung development results in cell differentiation and cell commitment in the primitive lung bud, in essence setting up a framework for pattern formation and branching morphogenesis. Branching morphogenesis results in the formation of the conductive airway system, which is critical for alveolization. Lung development is influenced at all stages by spatial and temporal distribution of various signaling molecules and their receptors and also by the positive and negative control of signaling by paracrine, autocrine, and endocrine mechanisms. Lung bud formation, cell differentiation, and its interaction with the splanchnic mesoderm are regulated by HNF-3beta, Shh, Nkx2.1, HNF-3/Forkhead homolog-8 (HFH-8), Gli, and GATA transcription factors. HNF-3beta regulates Nkx2.1, a transcription factor critical to the formation of distal pulmonary structures. Nkx2.1 regulates surfactant protein genes that are important for the development of alveolar stability at birth. Shh, produced by the foregut endoderm, regulates lung morphogenesis signaling through Gli genes expressed in the mesenchyme. FGF10, produced by the mesoderm, regulates branching morphogenesis via its receptors on the lung epithelium. Alveolization and formation of the capillary network are influenced by various factors that include PDGF, vascular endothelial growth factor (VEGF), and retinoic acid. Epithelial-endothelial interactions during lung development are important in establishing a functional blood-gas interface. The effects of various growth factors on lung development have been demonstrated by gain- or loss-of-function studies in null mutant and transgenic mice models. Understanding the role of growth factors and various other signaling molecules and their cellular interactions in lung development will provide us with new insights into the pathogenesis of bronchopulmonary dysplasia and disorders of lung morphogenesis.
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Affiliation(s)
- Vasanth H Kumar
- Department of Pediatrics (Neonatology), State University of New York, The Women & Children's Hospital of Buffalo, Buffalo, New York, USA
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28
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Moreno-Barriuso N, López-Malpartida AV, de Pablo F, Pichel JG. Alterations in alveolar epithelium differentiation and vasculogenesis in lungs of LIF/IGF-I double deficient embryos. Dev Dyn 2006; 235:2040-50. [PMID: 16691571 DOI: 10.1002/dvdy.20842] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
Previous studies on double deficient mice for leukemia inhibitory factor (LIF) and insulin-like growth factor I (IGF-I) reported that they died of respiratory failure, with abnormal lung histology and altered expression of pulmonary markers. Here we analyzed prenatal Lif/Igf-I double mutant mouse embryos to characterize LIF and IGF-I cooperative roles in distal lung epithelium and vascular maturation. Lungs of IGF-I-deficient embryos displayed a higher proportion of type II pneumocytes, less differentiated type I pneumocytes, and failure in alveolar capillary remodeling compared to wild type and LIF-deficient mice. Lif/Igf-I double knockout lungs showed aggravated pulmonary hypoplasia, lower airway volume, increased proliferation, and elevated levels of ERK1/2 activation. In addition, their alveoli were collapsed and lined by type II cells. The differentiation of type I cells barely occurred and capillaries remained in the abundant mesenchyme. These results indicate that LIF collaborates with IGF-I in lung alveolar epithelium and vascular maturation.
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Affiliation(s)
- Nuria Moreno-Barriuso
- Instituto de Biología Molecular y Celular del Cáncer, Consejo Superior de Investigaciones Científicas/Universidad de Salamanca, Salamanca, Spain
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29
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Auten RL, O'Reilly MA, Oury TD, Nozik-Grayck E, Whorton MH. Transgenic extracellular superoxide dismutase protects postnatal alveolar epithelial proliferation and development during hyperoxia. Am J Physiol Lung Cell Mol Physiol 2005; 290:L32-40. [PMID: 16100289 PMCID: PMC2661116 DOI: 10.1152/ajplung.00133.2005] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
Transgenic (TG) human (h) extracellular superoxide dismutase (EC-SOD) targeted to type II cells protects postnatal newborn mouse lung development against hyperoxia by unknown mechanisms. Because alveolar development depends on timely proliferation of type II epithelium and differentiation to type I epithelium, we measured proliferation in bronchiolar and alveolar (surfactant protein C-positive) epithelium in air and 95% O2-exposed wild-type (WT) and TG hEC-SOD newborn mice at postnatal days 3, 5, and 7 (P3-P7), traversing the transition from saccular to alveolar stages. We found that TG hEC-SOD ameliorated the 95% O2-impaired bromodeoxyuridine uptake in alveolar and bronchiolar epithelium at P3, but not at P5 and P7, when overall epithelial proliferation rates were lower in air-exposed WT mice. Mouse EC-, CuZn-, and Mn-SOD expression were unaffected by hyperoxia or genotype. TG mice had less DNA damage than 95% O2-exposed WT mice at P3, measured by TdT-mediated dUTP nick end labeling (P < 0.05). Hyperoxia induced cell-cycle inhibitory protein p21cip/waf mRNA at P3, WT > TG, P = 0.06. 95% O2 impaired apical expression of type I cell alpha protein (T1alpha) in WT but not in TG mice at P3 and increased T1alpha in WT and TG mice at P7. Reducing the 95% O2-induced impairment of epithelial proliferation at a critical window of lung development was associated with protection against DNA damage and preservation of apical T1alpha expression at P3.
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Affiliation(s)
- Richard L Auten
- Neonatal-Perinatal Research Institute, Department of Pediatrics, Duke University Medical Center, Durham, North Carolina 27710, USA.
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30
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Chapin CJ, Ertsey R, Yoshizawa J, Hara A, Sbragia L, Greer JJ, Kitterman JA. Congenital diaphragmatic hernia, tracheal occlusion, thyroid transcription factor-1, and fetal pulmonary epithelial maturation. Am J Physiol Lung Cell Mol Physiol 2005; 289:L44-52. [PMID: 15764645 DOI: 10.1152/ajplung.00342.2004] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Congenital diaphragmatic hernia (CDH) occurs in ∼1:2,500 human births and has high morbidity and mortality rates, primarily due to pulmonary hypoplasia and pulmonary hypertension. Tracheal occlusion (TO), in experimental animals, distends lungs and increases lung growth and alveolar type I cell maturation but decreases surfactant components and reduces alveolar type II cell density. We examined effects of CDH and CDH+TO on lung growth and maturation in fetal rats. To induce CDH, we administered nitrofen (100 mg) to dams at 9.5 days of gestation. We compared lungs from fetuses with CDH, CDH+TO, and those exposed to nitrofen without CDH. CDH decreased lung wet weight bilaterally ( P < 0.0001) and DNA content in lung ipsilateral to CDH ( P < 0.05). CDH+TO significantly increased lung wet weights bilaterally; DNA content was intermediate between CDH and NC. To evaluate effects on the distal pulmonary epithelium, we examined surfactant mRNA and protein levels, type I and II cell-specific markers (RTI40 and RTII70, respectively), and transcriptional regulator thyroid transcription factor-1 (TTF-1). Decreased lung distension (due to CDH) increased SP-C mRNA and TTF-1 protein expression and reduced RTI40 ( P < 0.05 for all). Increased lung distension (due to CDH+TO) reduced expression of SP mRNAs and pro-SP-C and TTF-1 proteins and enhanced expression of RTI40 (mRNA and protein; P < 0.05 for all). We conclude that CDH+TO partially reverses effects of CDH; it corrects the pulmonary hypoplasia and restores type I cell differentiation but adversely affects SP expression in type II cells. These effects may be mediated through changes in TTF-1 expression.
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Affiliation(s)
- Cheryl J Chapin
- Cardiovascular Research Institute, University of California, San Francisco, 94143, USA.
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31
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Chu S, Ferro TJ. Sp1: regulation of gene expression by phosphorylation. Gene 2005; 348:1-11. [PMID: 15777659 DOI: 10.1016/j.gene.2005.01.013] [Citation(s) in RCA: 191] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2004] [Revised: 12/15/2004] [Accepted: 01/24/2005] [Indexed: 11/28/2022]
Abstract
As the prototype of a family of transcription factors, Sp1 has been extensively studied and widely reported for its role in gene regulation. The first evidence of Sp1 phosphorylation was reported more than a decade ago. Since then, an increasing number of Sp1 phosphorylation events have been characterized. Recent data demonstrate an important role for the phosphorylation state of Sp1 in the regulation of multiple genes. In this article, we review published literature in four specific areas relating to the phosphorylation of Sp1: (1) signal transduction pathways for Sp1 phosphorylation, (2) mechanisms of Sp1 dephosphorylation, (3) the functional implications of Sp1 phosphorylation, and (4) Sp1 phosphorylation in the lung.
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Affiliation(s)
- Shijian Chu
- McGuire VA Medical Center, Richmond, VA 23249, USA.
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32
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Grasty RC, Wolf DC, Grey BE, Lau CS, Rogers JM. Prenatal window of susceptibility to perfluorooctane sulfonate-induced neonatal mortality in the Sprague-Dawley rat. ACTA ACUST UNITED AC 2004; 68:465-71. [PMID: 14745980 DOI: 10.1002/bdrb.10046] [Citation(s) in RCA: 88] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The critical period for increased neonatal mortality induced by perfluorooctane sulfonate (PFOS) exposure was evaluated in the rat. Timed-pregnant Sprague-Dawley rats were treated by oral gavage with 25 mg/kg/d PFOS/K(+) on four consecutive days (gestation days (GD) 2-5, 6-9, 10-13, 14-17, or 17-20) or with 0, 25, or 50 mg/kg/d PFOS/K(+) on GD 19-20. Controls received vehicle (10 ml/kg 0.5% Tween-20) on these days. Maternal weight gain was reduced in treated animals during dosing, as were food and water consumption. Following a 4-day treatment, litter size at birth was unaffected while pup weight was similarly reduced in the three earliest PFOS groups. All PFOS groups experienced decreases in survival while controls remained near 100%. Neonatal survival decreased in groups dosed later during gestation, approaching 100% with dosing on GD 17-20. Most deaths occurred before postnatal day (PND) 4, with the majority in the first 24 hours. Maternal serum PFOS levels on GD 21 were higher in groups exhibiting higher mortality. Following a 2-day treatment, PFOS groups experienced significant pup mortality by PND 1. Neonatal mortality continued through PND 5, when survival was 98, 66, and 3% for the 0, 25, and 50 mg/kg groups, respectively. Pup weight was reduced in treated groups with surviving litters. Gross dissection and histological examination of lungs revealed differences in maturation between control and treated animals on PND 0. We conclude that exposure to PFOS late in gestation is sufficient to induce 100% pup mortality and that inhibition of lung maturation may be involved.
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Affiliation(s)
- Rayetta C Grasty
- Reproductive Toxicology Division, National Health and Environmental Effects Research Laboratory, Office of Research and Development, US Environmental Protection Agency, Research Triangle Park, North Carolina 27711, USA.
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33
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Pan Q, Li C, Xiao J, Kimura S, Rubenstein J, Puelles L, Minoo P. In vivo characterization of the Nkx2.1 promoter/enhancer elements in transgenic mice. Gene 2004; 331:73-82. [PMID: 15094193 DOI: 10.1016/j.gene.2004.01.026] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2003] [Revised: 01/15/2004] [Accepted: 01/26/2004] [Indexed: 11/21/2022]
Abstract
Nkx2.1 encodes a homeodomain transcription factor whose expression is restricted to the thyroid, lung and specific regions of the forebrain. NKX2.1 plays a key role in the development of the latter organs. In lung epithelial cells, two regions of promoter activity, designated as proximal and distal promoters, map to DNA elements located upstream of exons 1 and 2 (within intron 1). That both promoters are active in vivo has been demonstrated by the presence of multiple Nkx2.1 mRNA species with distinct and appropriate exonic composition. The mechanisms of Nkx2.1 tissue selective gene expression remain entirely unknown. We have examined the potential of three overlapping DNA fragments, representing a total of approximately 4 kb of potential regulatory DNA from the baboon Nkx2.1 5' flanking region to direct expression of LacZ in transgenic mice during embryonic development. The three constructs include sequences in proximal, distal and both promoters separately. All three fragments directed LacZ expression to the brain of transgenic E15 and E18 mouse embryos. In addition to a number of other sites, all three constructs were active in subgroups of cells localized in the hypothalamus, a well-established site of endogenous Nkx2.1 gene expression. Two of the fragments conferred tracheal epithelial-specific LacZ gene expression, but parenchymal lung expression was not observed. None of the three fragments had activity in the thyroid. These data demonstrate the complexity of the Nkx2.1 tissue specific gene regulation and suggest that cis-active elements required for tracheal versus lung morphogenesis may be distinct. The same applies to the brain, which provides the most permissive environment for recognition of Nkx2.1 tissue specific cis-active elements.
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Affiliation(s)
- Qiuping Pan
- Department of Pediatrics, Women's and Children's Hospital, USC School of Medicine, LAC+USC Medical Center, 1801 E. Marengo Street, Room 1G1, Los Angeles, CA 9003, USA
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Kathuria H, Cao YX, Ramirez MI, Williams MC. Transcription of the caveolin-1 gene is differentially regulated in lung type I epithelial and endothelial cell lines. A role for ETS proteins in epithelial cell expression. J Biol Chem 2004; 279:30028-36. [PMID: 15138262 DOI: 10.1074/jbc.m402236200] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
In the lung, caveolin-1 is expressed in both type I alveolar epithelial and endothelial cells where it is hypothesized to modulate molecular signaling activities and progression of tumorigenesis. Developmentally, caveolin-1alpha is expressed in fetal lung endothelial, but not epithelial, cells; in adult lung, both cell types express caveolin-1alpha. To test the hypothesis that caveolin-1 transcription is differentially regulated in type I and endothelial cells, we characterized the proximal promoter of the mouse caveolin-1 gene in lung cell lines to identify factors that control its cell-specific expression. We show that caveolin-1 expression is regulated by an Ets cis-element in a lung epithelial cell line, but not a lung endothelial cell line, and that three ETS family members, ETS-1, PEA3, and ERM, recognize and bind the Ets site in the epithelial cell line. Based on these findings, we have identified the Ets cis-element as a region that accounts for differential transcriptional regulation of caveolin-1 in lung epithelial and endothelial cells.
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Affiliation(s)
- Hasmeena Kathuria
- Pulmonary Center, Department of Medicine, Boston University School of Medicine, Massachusetts 02118, USA.
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35
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Abstract
Recent studies demonstrate the capacity of BM-derived cells to engraft as differentiated cells of a variety of organs, including lung. In this paper, we review the current state-of-the-art in this area. We also summarize our work demonstrating that cultured adherent marrow cells can serve as progenitors of lung alveolar epithelium.
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Affiliation(s)
- D N Kotton
- The Pulmonary Center, Boston University School of Medicine, MA 02118, USA
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36
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Cao YX, Ramirez MI, Williams MC. Enhanced binding of Sp1/Sp3 transcription factors mediates the hyperoxia-induced increased expression of the lung type I cell gene T1alpha. J Cell Biochem 2003; 89:887-901. [PMID: 12874823 DOI: 10.1002/jcb.10555] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The transcription factor Sp1 plays an important regulatory role in transactivation of the lung type I cell differentiation gene T1alpha. Like other lung cells, type I cells may encounter changes in oxygen concentration during the lifetime of the organism. We found that exposure of mice to hyperoxia rapidly increases expression of T1alpha and other type I cell genes, and that returning the mice to normoxia quickly decreases expression. Likewise hyperoxia increases both endogenous T1alpha expression in lung epithelial cell lines and transcription of luciferase (Luc) from T1alpha promoter deletion constructs. Using wild-type promoter fragments and gel shift assays, we determined that Sp1/Sp3 and a key Sp cis-element in the proximal promoter mediate the hyperoxic response. Mutations of this element and inhibition of Sp-DNA binding by mithramycin block the hyperoxic response. Western analyses of cell homogenates show that the overall abundance of Sp1 and Sp3 proteins is not altered by hyperoxia. However, the abundance of nuclear Sp1 increases after short hyperoxic exposures, suggesting that signaling pathways activated by hyperoxia lead to Sp protein translocation, perhaps as a result of increased Sp phosphorylation.
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Affiliation(s)
- Yu-Xia Cao
- Pulmonary Center, Department of Medicine, Boston University School of Medicine, 715 Albany Street, Boston, MA 02118, USA
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37
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Abstract
Understanding of the functions and regulation of the phenotype of the alveolar type I epithelial cell has lagged behind studies of its neighbor the type II cell because of lack of cell-specific molecular markers. The recent identification of several proteins expressed by type I cells indicates that these cells may play important roles in regulation of cell proliferation, ion transport and water flow, metabolism of peptides, modulation of macrophage functions, and signaling events in the peripheral lung. Cell systems and reagents are available to characterize type I cell biology in detail, an important goal given that the cells provide the extensive surface that facilitates gas exchange in the intact animal.
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Affiliation(s)
- Mary C Williams
- Pulmonary Center and Department of Anatomy, Boston University School of Medicine, 715 Albany Street, Boston, Massachusetts 02118, USA.
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Chu S, Cockrell CA, Ferro TJ. Expression of alpha-ENaC2 is dependent on an upstream Sp1 binding motif and is modulated by protein phosphatase 1 in lung epithelial cells. Biochem Biophys Res Commun 2003; 303:1159-68. [PMID: 12684058 DOI: 10.1016/s0006-291x(03)00497-2] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The amiloride-sensitive Na(+) channel ENaC is expressed in lung epithelium and plays a pivotal role in lung fluid clearance in the newborn. Multiple splice variants of the ENaC alpha-subunit have been reported. Among them, alpha-ENaC2 accounts for a considerable portion of alpha-ENaC transcripts in human lung and kidney, possesses channel functions similar to alpha-ENaC1, and is driven by a downstream promoter. In the current study, we examine the regulation of alpha-ENaC2 transcription in lung epithelial cells. We found that transcription factors Sp1 and Sp3 activate alpha-ENaC2 transcription through a GC-rich element (Sp1-binding site) in the promoter. Because alpha-ENaC expression and Sp1 phosphorylation are both significantly up-regulated in the perinatal lung, we then examined the possible connection between Sp1/Sp3 phosphorylation and alpha-ENaC2 expression. We found that protein phosphatase 1 (PP1) dephosphorylates Sp1 and Sp3 in lung epithelial cells, reduces their binding to the alpha-ENaC2 promoter, and decreases Sp1/Sp3-mediated promoter activity. Our results suggest that Sp1 and Sp3 are essential for alpha-ENaC2 transcription in lung epithelial cells and that dephosphorylation of the Sp transcription factors by PP1 suppresses alpha-ENaC2 expression. The significance of these findings in the regulation of gene expression in perinatal lung is discussed.
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Affiliation(s)
- Shijian Chu
- Department of Veterans Affairs Medical Center, McGuire Research Institute, Richmond, VA 23249, USA.
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Ramirez MI, Millien G, Hinds A, Cao Y, Seldin DC, Williams MC. T1alpha, a lung type I cell differentiation gene, is required for normal lung cell proliferation and alveolus formation at birth. Dev Biol 2003; 256:61-72. [PMID: 12654292 DOI: 10.1016/s0012-1606(02)00098-2] [Citation(s) in RCA: 207] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
T1alpha, a differentiation gene of lung alveolar epithelial type I cells, is developmentally regulated and encodes an apical membrane protein of unknown function. Morphological differentiation of type I cells to form the air-blood barrier starts in the last few days of gestation and continues postnatally. Although T1alpha is expressed in the foregut endoderm before the lung buds, T1alpha mRNA and protein levels increase substantially in late fetuses when expression is restricted to alveolar type I cells. We generated T1alpha null mutant mice to study the role of T1alpha in lung development and differentiation and to gain insight into its potential function. Homozygous null mice die at birth of respiratory failure, and their lungs cannot be inflated to normal volumes. Distal lung morphology is altered. In the absence of T1alpha protein, type I cell differentiation is blocked, as indicated by smaller airspaces, many fewer attenuated type I cells, and reduced levels of aquaporin-5 mRNA and protein, a type I cell water channel. Abundant secreted surfactant in the narrowed airspaces, normal levels of surfactant protein mRNAs, and normal patterns and numbers of cells expressing surfactant protein-B suggest that differentiation of type II cells, also alveolar epithelial cells, is normal. Anomalous proliferation of the mesenchyme and epithelium at birth with unchanged numbers of apoptotic cells suggests that loss of T1alpha and/or abnormal morphogenesis of type I cells alter the proliferation rate of distal lung cells, probably by disruption of epithelial-mesenchymal signaling.
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Affiliation(s)
- Maria I Ramirez
- Pulmonary Center, Boston University School of Medicine, Boston, MA 02118, USA.
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Abstract
Tissue-specific gene expression is mediated largely by transcription factors, and a master regulatory gene is thus a potential marker of cellular lineage. Using normal fetal through adult pulmonary tissues and 64 consecutive lung adenocarcinomas, we examined the expression of thyroid transcription factor (TTF-1), which plays a crucial role in normal lung function and morphogenesis. TTF-1 was expressed consistently throughout the life stages and uniformly in the terminal respiratory unit, which is comprised of peripheral airway cells and small-sized bronchioles. Furthermore, the expression was maintained in 72% of adenocarcinomas that exhibited high correlation with surfactant apoprotein (p <0.001) and morphologic resemblance to terminal respiratory unit cells (p <0.001). The staining pattern was also uniform in the adenocarcinomas despite histologic and microenvironmental diversity in individual tumors and their metastatic foci. This consistency and uniformity, therefore, suggested that TTF-1 expression could be used as a lineage marker of terminal respiratory unit. We also identified interesting distinctions between TTF-1-positive and -negative adenocarcinomas based on their clinicopathologic features and expression of various cancer-associated genes. TTF-1-positive adenocarcinomas had statistically significant prevalence of female (p <0.01), nonsmoker (p <0.05), negative p53 staining (p <0.01), less frequent RB loss (p <0.05), and preserved expression of p27 (p <0.01). The results supported the TTF-1 lineage marker and suggested that molecular pathogenesis may in part be characterized by cellular lineage.
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Affiliation(s)
- Yasushi Yatabe
- Department of Anatomic and Molecular Diagnostic Pathology, Aichi Cancer Center Hospital, Aichi Cancer Center Research Institute, Nagoya, Japan.
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Miccadei S, De Leo R, Zammarchi E, Natali PG, Civitareale D. The synergistic activity of thyroid transcription factor 1 and Pax 8 relies on the promoter/enhancer interplay. Mol Endocrinol 2002; 16:837-46. [PMID: 11923479 DOI: 10.1210/mend.16.4.0808] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
The transcription factors, thyroid transcription factor 1 (TTF-1) and Pax 8, play a pivotal role in the transcriptional regulation of the thyroid differentiation marker genes and in the differentiation of the thyroid follicular cells. They have a very restricted tissue distribution, and the thyrocyte is the only cell type with the simultaneous expression of these factors. Here we show that TTF-1 and Pax 8 cooperatively activate their target genes and that their synergistic activity requires the cross-talk between enhancer and gene promoter. We have characterized the cis and trans requirements of the TTF1/Pax 8 synergistic activity on the thyroperoxidase gene. We show that their synergy is also important for thyroglobulin gene transcription.
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Affiliation(s)
- Stefania Miccadei
- Laboratory of Immunology, Regina Elena Cancer Institute, Rome 00158, Italy
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42
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Lonigro R, Donnini D, Zappia E, Damante G, Bianchi ME, Guazzi S. Nestin is a neuroepithelial target gene of thyroid transcription factor-1, a homeoprotein required for forebrain organogenesis. J Biol Chem 2001; 276:47807-13. [PMID: 11584016 DOI: 10.1074/jbc.m107692200] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Thyroid transcription factor-1 (TTF-1, also known as NKX2.1 and T/EBP), a transcription factor belonging to the NKX-2 family of homeodomain-containing genes, plays an essential role in the organogenesis of the thyroid gland, lung, and ventral forebrain. Nestin is an intermediate filament protein strongly expressed in multipotential neuroepithelial stem cells and rapidly down-regulated during postnatal life. Here we show that stable fibroblastic clones expressing TTF-1 acquire a phenotype reminiscent of neuroepithelial cells in culture and up-regulate the endogenous nestin gene. TTF-1 transactivates in HeLa and NIH3T3 cells a reporter gene driven by a central nervous system-specific enhancer element from the second intron of the rat nestin gene, where it recognizes a DNA-binding site (NestBS) whose sequence resembles a nuclear hormone/cAMP-responsive element very different from canonical TTF-1 binding sites. Nuclear extracts from the head of mouse embryos form a retarded complex with NestBS of the same mobility of the extracts obtained from TTF1-expressing clones, which is either abolished or supershifted in the presence of two different antibodies recognizing the TTF-1 protein. Thus, the neuroepithelial marker nestin is a direct central nervous system-specific target gene of TTF-1, leading to the hypothesis that it might be the effector through which TTF-1 plays its role in the organogenesis of the forebrain.
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Affiliation(s)
- R Lonigro
- Department of Biology and Biotechnology, S. Raffaele Scientific Institute, Via Olgettina, 58, Milano 20132, Italy
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43
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Costa RH, Kalinichenko VV, Lim L. Transcription factors in mouse lung development and function. Am J Physiol Lung Cell Mol Physiol 2001; 280:L823-38. [PMID: 11290504 DOI: 10.1152/ajplung.2001.280.5.l823] [Citation(s) in RCA: 177] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Development of the mouse lung initiates on day 9.5 postcoitum from the laryngotracheal groove and involves mesenchymal-epithelial interactions, in particular, those between the splanchnic mesoderm and epithelial cells (derived from foregut endoderm) that induce cellular proliferation, migration, and differentiation, resulting in branching morphogenesis. This developmental process mediates formation of the pulmonary bronchiole tree and integrates a terminal alveolar region with an extensive endothelial capillary bed, which facilitates efficient gas exchange with the circulatory system. The major function of the mesenchymal-epithelial signaling is to potentiate the activity or expression of cell type-specific transcription factors in the developing lung, which, in turn, cooperatively bind to distinct promoter regions and activate target gene expression. In this review, we focus on the role of transcription factors in lung morphogenesis and the maintenance of differentiated gene expression. These lung transcription factors include forkhead box A2 [also known as hepatocyte nuclear factor (HNF)-3beta], HNF-3/forkhead homolog (HFH)-8 [also known as FoxF1 or forkhead-related activator-1], HNF-3/forkhead homolog-4 (also known as FoxJ1), thyroid transcription factor-1 (Nkx2.1), and homeodomain box A5 transcription factors, the zinc finger Gli (mouse homologs of the Drosophila cubitus interruptus) and GATA transcription factors, and the basic helix-loop-helix Pod1 transcription factor. We summarize the phenotypes of transgenic and knockout mouse models, which define important functions of these transcription factors in cellular differentiation and lung branching morphogenesis.
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Affiliation(s)
- R H Costa
- Department of Molecular Genetics, College of Medicine, University of Illinois at Chicago, Chicago, Illinois 60607-7170, USA
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Nord M, Cassel TN, Braun H, Suske G. Regulation of the Clara cell secretory protein/uteroglobin promoter in lung. Ann N Y Acad Sci 2001; 923:154-65. [PMID: 11193754 DOI: 10.1111/j.1749-6632.2000.tb05527.x] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Clara cell secretory protein/uteroglobin (CCSP/UG) is specifically expressed in the conducting airway epithelium of the lung in a differentiation-dependent manner. The proximal promoter region of the rodent CCSP/UG gene directs Clara cell specificity. Previously, it was shown that the forkhead transcription factors HNF-3 alpha and beta and the homeodomain factor TTF-1 are important transcription factors acting through this region, suggesting that they contribute to cell specificity of the CCSP/UG gene. Members of the C/EBP family of transcription factors can also interact with elements of the proximal rat and mouse CCSP/UG promoters. The onset of C/EBP alpha expression in Clara cells correlates with the strong increase of CCSP/UG expression. Thus, C/EBP alpha may play a crucial role for differentiation-dependent CCSP/UG expression. Transfection studies demonstrate that C/EBP alpha and TTF-1 can synergistically activate the murine CCSP/UG promoter. Altogether, these results suggest that C/EBP alpha, TTF-1, and HNF-3 determine the Clara cell-specific, differentiation-dependent expression of the CCSP/UG gene in murine lung. The relative importance of these three transcription factors, however, differs in rabbits and humans.
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Affiliation(s)
- M Nord
- Department of Medical Nutrition, Karolinska Institute, NOVUM, Huddinge University Hospital, SE-141 86 Huddinge, Sweden.
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Damante G, Tell G, Di Lauro R. A unique combination of transcription factors controls differentiation of thyroid cells. PROGRESS IN NUCLEIC ACID RESEARCH AND MOLECULAR BIOLOGY 2001; 66:307-56. [PMID: 11051768 DOI: 10.1016/s0079-6603(00)66033-6] [Citation(s) in RCA: 140] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The thyroid follicular cell type is devoted to the synthesis of thyroid hormones. Several genes, whose protein products are essential for efficient hormone biosynthesis, are uniquely expressed in this cell type. A set of transcriptional regulators, unique to the thyroid follicular cell type, has been identified as responsible for thyroid specific gene expression; it comprises three transcription factors, named TTF-1, TTF-2, and Pax8, each of which is expressed also in cell types different from the thyroid follicular cells. However, the combination of these factors is unique to the thyroid hormone producing cells, strongly suggesting that they play an important role in differentiation of these cells. An overview of the molecular and biological features of these transcription factors is presented here. Data demonstrating that all three play also an important role in early thyroid development, at stages preceding expression of the differentiated phenotype, are also reviewed. The wide temporal expression, from the beginning of thyroid organogenesis to the adult state, is suggestive of a recycling of the thyroid-specific transcription factors, that is, the control of different sets of target genes at diverse developmental stages. The identification of molecular mechanisms leading to specific gene expression in thyroid cells renders this cell type an interesting model in which to address several aspects of cell differentiation and organogenesis.
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Affiliation(s)
- G Damante
- Dipartimento di Scienze e Tecnologie Biomediche Università di Udine
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Yang YS, Yang MC, Wang B, Weissler JC. BR22, a novel protein, interacts with thyroid transcription factor-1 and activates the human surfactant protein B promoter. Am J Respir Cell Mol Biol 2001; 24:30-37. [PMID: 11152647 DOI: 10.1165/ajrcmb.24.1.4050] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Surfactant protein (SP)-B expression is restricted to type II pneumocytes and Clara cells in the lung. Previously, a promoter region of human SP-B gene from -64 to -118 has been identified as critical for the tissue-specific expression of this gene. Two cis-elements for thyroid transcription factor (TTF)-1 and hepatocyte nuclear factor (HNF)-3alpha binding were found within this area. Using an oligonucleotide fragment, we incorporated this region sequence into the promoter of a HIS3 reporter gene in yeast. With this modified yeast a human lung complementary DNA (cDNA) library was screened for DNA-binding proteins, other than TTF-1 and HNF-3alpha, that interacted with this promoter segment. A cDNA clone encoding a novel polypeptide, BR22, was identified that activated the reporter gene expression in yeast. This gene is expressed in many tissues and encodes a protein with bipartite nuclear localization signals. Studies using in vivo yeast two-hybrid analysis, in vitro protein-protein interactions, and coimmunoprecipitation analyses demonstrated that BR22 formed a protein complex with TTF-1. In vivo cotransfection studies further indicated that BR22 could act with TTF-1 to synergistically activate the SP-B promoter in mammalian cells. Our data suggest that BR22 is a TTF-1-associated protein. Through a protein-protein interaction with TTF-1, BR22 can form a complex and activate the human SP-B promoter in vivo.
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Affiliation(s)
- Y S Yang
- Department of Internal Medicine, Pulmonary and Critical Care Medicine, UT Southwestern Medical Center, Dallas, Texas 75390-9034, USA.
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47
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Morotti RA, Gutierrez MC, Askin F, Profitt SA, Wert SE, Whitsett JA, Greco MA. Expression of thyroid transcription factor-1 in congenital cystic adenomatoid malformation of the lung. Pediatr Dev Pathol 2000; 3:455-61. [PMID: 10890930 DOI: 10.1007/s100240010092] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Congenital cystic adenomatoid malformation (CCAM) is an abnormality of branching morphogenesis of the lung. CCAM types 1, 2, and 3 exhibit a cellular composition that is different from that of CCAM type 4 when evaluated with bronchiolar and alveolar cell markers. Thyroid transcription factor 1 (TTF-1) regulates early lung development. To evaluate the potential role of TTF-1 in the development of CCAM, TTF-1 expression in CCAM was compared to that of fetal lungs at varying gestational ages. Twenty-three CCAM cases (17 type 1, two type 2, two type 3, and two type 4) and 11 fetal lungs (3 pseudoglandular, 4 canalicular, and 4 terminal sac stages) were analyzed using a rabbit polyclonal antiserum to rat TTF-1. Nuclear staining for TTF-1 was observed in ciliated and nonciliated cells of the bronchial and bronchiolar epithelia and in cells lining the distal air spaces by 12 weeks gestational age. By mid-gestation, proximal bronchial cells were TTF-1 negative, except for the basal cells, while TTF-1 staining was maintained in distal bronchiolar and alveolar cells. TTF-1 expression decreased in both bronchial, bronchiolar, and alveolar epithelia with advancing gestational age and cytodifferentiation. At term, TTF-1 expression persisted in a few bronchial and bronchiolar basal cells and in all alveolar type II cells, whereas type I cells were negative. In CCAM, TTF-1 was detected in the nuclei of epithelial cells lining the cysts. TTF-1 was expressed in a majority of the bronchiolar-like epithelial cells of the cysts in CCAM types 1, 2, and 3, where almost 100% of the cells were TTF-1 positive. In contrast, TTF-1 expression in the alveolar-like epithelium of CCAM type 4 cysts was restricted to type II cells and only 30%-60% of the lining cells were TTF-1 positive. These results support the hypothesis that CCAM types 1, 2, and 3 reflect abnormalities in lung morphogenesis and differentiation that are distinct from those for CCAM type 4. The role played by TTF-1 in the development of CCAM, if any, is not clear.
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Affiliation(s)
- R A Morotti
- Department of Pathology, Children's Hospital, 700 Children's Drive, Columbus, OH 43205, USA
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48
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Borok Z, Li X, Fernandes VF, Zhou B, Ann DK, Crandall ED. Differential regulation of rat aquaporin-5 promoter/enhancer activities in lung and salivary epithelial cells. J Biol Chem 2000; 275:26507-14. [PMID: 10849430 DOI: 10.1074/jbc.m910007199] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Aquaporin-5 (AQP5) is a water channel protein that is selectively expressed in respiratory, salivary, and lacrimal tissues. In order to establish the tissue-specific transcriptional programs that underlie its lung- and salivary-specific expression, a 4.5-kilobase pair DNA fragment encompassing the 5'-flanking region of the rat AQP5 gene has been characterized in detail. A major transcription start site utilized in lung and salivary glands has been localized downstream of a TATAA-like motif. Transient transfection assays of -4.3- and -1.7-AQP5-luciferase constructs in AQP5-expressing lung (MLE-15) and salivary (Pa-4) cells and nonexpressing fibroblast (NIH3T3) and epithelial (HeLa) cells demonstrate preferential transcriptional enhancement of reporter activities in MLE-15 and Pa-4 cells. Transient transfection assays of a series of 5' --> 3' deletion constructs of -4.3-AQP5-luciferase suggest that a common salivary and lung enhancer is located between nucleotides -274 and -139, and a lung-specific enhancer is located between nucleotides -894 and -710. There is one putative lung-specific repressor located in the region of nucleotides -1003/-894 and a common lung and salivary repressor located at nucleotides -503/-385. Moreover, 3' --> 5' deletions up to -171 and -127 base pairs almost abolish transcriptional activation in salivary and lung cells, respectively. Together, our findings indicate that the combination of enhancer/repressor elements within the proximal 5'-flanking region of rat AQP5 gene dictates its restricted expression in both lung and salivary cells.
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Affiliation(s)
- Z Borok
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, Will Rogers Institute Pulmonary Research Center, Los Angeles, CA 90033, USA.
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49
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Wright RM, Riley MG, Weigel LK, Ginger LA, Costantino DA, McManaman JL. Activation of the human aldehyde oxidase (hAOX1) promoter by tandem cooperative Sp1/Sp3 binding sites: identification of complex architecture in the hAOX upstream DNA that includes a proximal promoter, distal activation sites, and a silencer element. DNA Cell Biol 2000; 19:459-74. [PMID: 10975464 DOI: 10.1089/10445490050128395] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Aldehyde oxidase (AOX) is a member of the molybdenum iron-sulfur flavoproteins and is of interest for its role in clinical drug metabolism and as a source of reactive oxygen species (ROS) potentially involved in human pathology. The ROS derived from AOX contribute significantly to alcohol-induced hepatotoxicity. Therefore, expression of AOX could determine both the susceptibility of certain cells and tissues to clinically important pharmacologic agents and the levels of ROS produced under certain pathophysiological conditions. Although some pharmacologic agents regulate AOX enzyme activity, very little is known about the activation or regulation of the human AOX gene (hAOX). In the present study, we sought to identify features in the upstream DNA of hAOX that could confer regulation of the gene, to locate and characterize the basal promoter apparatus activating hAOX, and to identify transcription factors that could mediate activation or regulation. We transfected promoter fusion constructs into epithelial cells from the lung and the mammary gland that express AOX in cell culture. The hAOX gene was found to possess a structurally complex region in the upstream DNA that contained sequences for a proximal promoter, enhancer sites, and silencer elements. In addition, we identified an essential role for the transcription factors Sp1 and Sp3 in the proximal promoter. Unexpectedly, hAOX was activated in lung and mammary epithelial cells by indistinguishable mechanisms. These observations reveal a potentially complex mode of hAOX gene expression in epithelial cells that is dependent on Spl and Sp3 transcription factors.
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Affiliation(s)
- R M Wright
- The Webb-Waring Institute and Department of Medicine, The University of Colorado Health Sciences Center, Denver 80262, USA.
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50
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Li C, Cai J, Pan Q, Minoo P. Two functionally distinct forms of NKX2.1 protein are expressed in the pulmonary epithelium. Biochem Biophys Res Commun 2000; 270:462-8. [PMID: 10753648 DOI: 10.1006/bbrc.2000.2443] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The homeodomain transcriptional factor NKX2.1 is critical for normal morphogenesis of the lung, thyroid, and the brain. In the lung, NKX2. 1 binds to and activates the expression of pulmonary differentiation-specific genes SP-A, SP-B, and SP-C. The Nkx2.1 gene is comprised of three exons separated by two introns. In both thyroid and lung, the predominant Nkx2.1 transcript includes exons II and III and is translated into a 371 amino acid protein. A minor transcript also exists which includes all three exons. This transcript encodes a 401 amino acid isoform of NKX2.1. The 30 amino acid extension is highly conserved amongst various mammalian species. In the current study, we demonstrate that the two NKX2.1 isoforms are functionally distinct and their corresponding transcripts are expressed differentially during mouse embryonic lung development. The results demonstrate that the longer isoform of NKX2.1 exhibits reduced activity in transactivating an SP-C target promoter when compared to the truncated major NKX2.1 protein. Site directed mutagenesis of the 30 amino acid peptide extension suggests that this fragment alters the activity of 5E likely by steric interference.
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Affiliation(s)
- C Li
- Department of Pediatrics, Women's & Children's Hospital, University of Southern California School of Medicine, Los Angeles, California 90033, USA
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