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Liang W, Lu H, Sun J, Zhao G, Wang H, Guo Y, Eitzman D, Chen YE, Fan Y, Zhang J. KLF11 Protects against Venous Thrombosis via Suppressing Tissue Factor Expression. Thromb Haemost 2022; 122:777-788. [PMID: 34428834 PMCID: PMC10468287 DOI: 10.1055/s-0041-1735191] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
Krüppel-like factors (KLFs) play essential roles in multiple biological functions, including maintaining vascular homeostasis. KLF11, a causative gene for maturity-onset diabetes of the young type 7, inhibits endothelial activation and protects against stroke. However, the role of KLF11 in venous thrombosis remains to be explored. Utilizing stasis-induced murine deep vein thrombosis (DVT) model and cultured endothelial cells (ECs), we identified an increase of KLF11 expression under prothrombotic conditions both in vivo and in vitro. The expression change of thrombosis-related genes was determined by utilizing gain- and loss-of-function approaches to alter KLF11 expression in ECs. Among these genes, KLF11 significantly downregulated tumor necrosis factor-α (TNF-α)-induced tissue factor (TF) gene transcription. Using reporter gene assay, chromatin immunoprecipitation assay, and co-immunoprecipitation, we revealed that KLF11 could reduce TNF-α-induced binding of early growth response 1 (EGR1) to TF gene promoter in ECs. In addition, we demonstrated that conventional Klf11 knockout mice were more susceptible to developing stasis-induced DVT. These results suggest that under prothrombotic conditions, KLF11 downregulates TF gene transcription via inhibition of EGR1 in ECs. In conclusion, KLF11 protects against venous thrombosis, constituting a potential molecular target for treating thrombosis.
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Affiliation(s)
- Wenying Liang
- Department of Internal Medicine, Frankel Cardiovascular Center, University of Michigan Medical Center, Ann Arbor, Michigan, United States
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, Michigan, Unites States
| | - Haocheng Lu
- Department of Internal Medicine, Frankel Cardiovascular Center, University of Michigan Medical Center, Ann Arbor, Michigan, United States
| | - Jinjian Sun
- Department of Internal Medicine, Frankel Cardiovascular Center, University of Michigan Medical Center, Ann Arbor, Michigan, United States
| | - Guizhen Zhao
- Department of Internal Medicine, Frankel Cardiovascular Center, University of Michigan Medical Center, Ann Arbor, Michigan, United States
| | - Huilun Wang
- Department of Internal Medicine, Frankel Cardiovascular Center, University of Michigan Medical Center, Ann Arbor, Michigan, United States
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, Michigan, Unites States
| | - Yanhong Guo
- Department of Internal Medicine, Frankel Cardiovascular Center, University of Michigan Medical Center, Ann Arbor, Michigan, United States
| | - Daniel Eitzman
- Department of Internal Medicine, Frankel Cardiovascular Center, University of Michigan Medical Center, Ann Arbor, Michigan, United States
| | - Y Eugene Chen
- Department of Internal Medicine, Frankel Cardiovascular Center, University of Michigan Medical Center, Ann Arbor, Michigan, United States
| | - Yanbo Fan
- Department of Cancer Biology, University of Cincinnati College of Medicine, Cincinnati, Ohio, Unites States
- Division of Cardiovascular Health and Disease, Department of Internal Medicine, University of Cincinnati College of Medicine, Cincinnati, Ohio, Unites States
| | - Jifeng Zhang
- Department of Internal Medicine, Frankel Cardiovascular Center, University of Michigan Medical Center, Ann Arbor, Michigan, United States
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Martin-Broto J, Mondaza-Hernandez JL, Moura DS, Hindi N. A Comprehensive Review on Solitary Fibrous Tumor: New Insights for New Horizons. Cancers (Basel) 2021; 13:cancers13122913. [PMID: 34200924 PMCID: PMC8230482 DOI: 10.3390/cancers13122913] [Citation(s) in RCA: 58] [Impact Index Per Article: 19.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Revised: 06/01/2021] [Accepted: 06/04/2021] [Indexed: 12/16/2022] Open
Abstract
Simple Summary Solitary fibrous tumor (SFT) is a malignant condition that exhibits different clinical behaviors ranging from low to high aggressive SFT, with dedifferentiated SFT (DD-SFT) being the fastest-growing subtype. Even when surgery alone provides curation rates above 60%, recurrences do occur in a fraction of patients where surgery is unable to provide disease control. Among the systemic therapeutic options, antiangiogenic compounds have shown higher efficacy than chemotherapy by indirect comparisons. Furthermore, rotating different antiangiogenics, at the progression time, has been shown to be effective. The exception is DD-SFT since it is resistant to antiangiogenics but can respond to chemotherapy. This comprehensive review also analyzes the underlying molecular components that play a key role in SFT origin and aggressiveness. The discovery in 2013 of anomalous fusion genes between NAB2 and STAT6 was determinant to increase the knowledge on the molecular drivers in SFT that could be potential targets for future therapies. Abstract Solitary fibrous tumor (SFT) is a rare mesenchymal, ubiquitous tumor, with an incidence of 1 new case/million people/year. In the 2020 WHO classification, risk stratification models were recommended as a better tool to determine prognosis in SFT, to the detriment of “typical” or “malignant” classic terms. The risk for metastasis is up to 35–45%, or even greater, in series with a longer follow-up. Over the last few decades, advances in immunohistochemistry and molecular diagnostics identified STAT6 nuclear protein expression and the NAB2–STAT6 fusion gene as more precise tools for SFT diagnosis. Recent evidence taken from retrospective series and from two prospective phase II clinical trials showed that antiangiogenics are active and their sequential use from first line should be considered, except for dedifferentiated SFT for which chemotherapy is the best option. Since the fusion transcript driver’s first description in 2013, new insights have been brought on key molecular events in SFT. This comprehensive review mainly focuses on the superior efficacy of antiangiogenics over chemotherapeutic agents in SFT, provides the current knowledge of key molecules that could co-drive the SFT behavior, and suggests new target candidates that deserve to be explored in preclinical and clinical research in SFT.
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Affiliation(s)
- Javier Martin-Broto
- Fundacion Jimenez Díaz University Hospital, 28040 Madrid, Spain;
- General de Villalba University Hospital, Collado Villalba, 28400 Madrid, Spain
- Fundación Jiménez Díaz Institute for Medical Research (IIS/FJD), 28040 Madrid, Spain
- Correspondence:
| | - Jose L. Mondaza-Hernandez
- Institute of Biomedicine of Seville (IBiS, CSIC, US and HUVR), 41013 Sevilla, Spain; (J.L.M.-H.); (D.S.M.)
| | - David S. Moura
- Institute of Biomedicine of Seville (IBiS, CSIC, US and HUVR), 41013 Sevilla, Spain; (J.L.M.-H.); (D.S.M.)
| | - Nadia Hindi
- Fundacion Jimenez Díaz University Hospital, 28040 Madrid, Spain;
- General de Villalba University Hospital, Collado Villalba, 28400 Madrid, Spain
- Fundación Jiménez Díaz Institute for Medical Research (IIS/FJD), 28040 Madrid, Spain
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Bieg M, Moskalev EA, Will R, Hebele S, Schwarzbach M, Schmeck S, Hohenberger P, Jakob J, Kasper B, Gaiser T, Ströbel P, Wardelmann E, Kontny U, Braunschweig T, Sirbu H, Grützmann R, Meidenbauer N, Ishaque N, Eils R, Wiemann S, Hartmann A, Agaimy A, Fritchie K, Giannini C, Haller F. Gene Expression in Solitary Fibrous Tumors (SFTs) Correlates with Anatomic Localization and NAB2-STAT6 Gene Fusion Variants. THE AMERICAN JOURNAL OF PATHOLOGY 2021; 191:602-617. [PMID: 33497701 DOI: 10.1016/j.ajpath.2020.12.015] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/17/2020] [Revised: 11/27/2020] [Accepted: 12/31/2020] [Indexed: 12/17/2022]
Abstract
Solitary fibrous tumors (SFTs) harbor recurrent NAB2-STAT6 gene fusions, promoting constitutional up-regulation of oncogenic early growth response 1 (EGR1)-dependent gene expression. SFTs with the most common canonical NAB2 exon 4-STAT6 exon 2 fusion variant are often located in the thorax (pleuropulmonary) and are less cellular with abundant collagen. In contrast, SFTs with NAB2 exon 6-STAT6 exon 16/17 fusion variants typically display a cellular round to ovoid cell morphology and are often located in the deep soft tissue of the retroperitoneum and intra-abdominal pelvic region or in the meninges. Here, we employed next-generation sequencing-based gene expression profiling to identify significant differences in gene expression associated with anatomic localization and NAB2-STAT6 gene fusion variants. SFTs with the NAB2 exon 4-STAT6 exon 2 fusion variant showed a transcriptional signature enriched for genes involved in DNA binding, gene transcription, and nuclear localization, whereas SFTs with the NAB2 exon 6-STAT6 exon 16/17 fusion variants were enriched for genes involved in tyrosine kinase signaling, cell proliferation, and cytoplasmic localization. Specific transcription factor binding motifs were enriched among differentially expressed genes in SFTs with different fusion variants, implicating co-transcription factors in the modification of chimeric NGFI-A binding protein 2 (NAB2)-STAT6-dependent deregulation of EGR1-dependent gene expression. In summary, this study establishes a potential molecular biologic basis for clinicopathologic differences in SFTs with distinct NAB2-STAT6 gene fusion variants.
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Affiliation(s)
- Matthias Bieg
- Center for Digital Health, Berlin Institute of Health and Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Evgeny A Moskalev
- Institute of Pathology, University Hospital Erlangen, Friedrich-Alexander University Erlangen-Nuremberg, Erlangen, Germany
| | - Rainer Will
- Genomics and Proteomics Core Facility, German Cancer Research Center, Heidelberg, Germany
| | - Simone Hebele
- Institute of Pathology, University Hospital Erlangen, Friedrich-Alexander University Erlangen-Nuremberg, Erlangen, Germany
| | | | - Sanja Schmeck
- Institute of Pathology, Clinical Center Frankfurt Höchst, Frankfurt, Germany
| | - Peter Hohenberger
- Division of Surgical Oncology and Thoracic Surgery, Department of Surgery, University Medical Center Mannheim, Medical Faculty Mannheim, University of Heidelberg, Mannheim, Germany
| | - Jens Jakob
- Division of Surgical Oncology and Thoracic Surgery, Department of Surgery, University Medical Center Mannheim, Medical Faculty Mannheim, University of Heidelberg, Mannheim, Germany; Department of General, Visceral and Pediatric Surgery, University Medical Center Göttingen, Göttingen, Germany
| | - Bernd Kasper
- Sarcoma Unit, Interdisciplinary Tumor Center Mannheim, University Medical Center Mannheim, Medical Faculty Mannheim, University of Heidelberg, Mannheim, Germany
| | - Timo Gaiser
- Institute of Pathology, University Medical Center Mannheim, Medical Faculty Mannheim, University of Heidelberg, Mannheim, Germany
| | - Philip Ströbel
- Institute of Pathology, University Medical Center Göttingen, Göttingen, Germany
| | - Eva Wardelmann
- Gerhard-Domagk-Institute of Pathology, University Hospital Münster, Münster, Germany
| | - Udo Kontny
- Division of Pediatric Hematology Oncology and Stem Cell Transplantation, Medical Faculty, RWTH Aachen University, Aachen, Germany
| | | | - Horia Sirbu
- Department of Thoracic Surgery, University Hospital Erlangen, Friedrich-Alexander University Erlangen-Nuremberg, Erlangen, Germany
| | - Robert Grützmann
- Department of Surgery, University Hospital Erlangen, University Hospital Erlangen, Friedrich-Alexander University Erlangen-Nuremberg, Erlangen, Germany
| | - Norbert Meidenbauer
- Department of Internal Medicine 5, Hematology and Oncology, Friedrich-Alexander University Erlangen-Nuremberg, Erlangen, Germany
| | - Naveed Ishaque
- Center for Digital Health, Berlin Institute of Health and Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Roland Eils
- Center for Digital Health, Berlin Institute of Health and Charité-Universitätsmedizin Berlin, Berlin, Germany; Health Data Science Unit, University Hospital Heidelberg, Heidelberg, Germany
| | - Stefan Wiemann
- Genomics and Proteomics Core Facility, German Cancer Research Center, Heidelberg, Germany; Division of Molecular Genome Analysis, German Cancer Research Center, Heidelberg, Germany
| | - Arndt Hartmann
- Institute of Pathology, University Hospital Erlangen, Friedrich-Alexander University Erlangen-Nuremberg, Erlangen, Germany
| | - Abbas Agaimy
- Institute of Pathology, University Hospital Erlangen, Friedrich-Alexander University Erlangen-Nuremberg, Erlangen, Germany
| | - Karen Fritchie
- Anatomic Pathology, Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, Minnesota, Italy
| | - Caterina Giannini
- Anatomic Pathology, Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, Minnesota, Italy; Anatomic Pathology, Dipartimento di Scienze Biomediche e NeuroMotorie-DIBINEM-Alma Mater Studiorum-Università di Bologna, Bologna, Italy
| | - Florian Haller
- Institute of Pathology, University Hospital Erlangen, Friedrich-Alexander University Erlangen-Nuremberg, Erlangen, Germany.
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Thompson RL, Sawtell NM. Targeted Promoter Replacement Reveals That Herpes Simplex Virus Type-1 and 2 Specific VP16 Promoters Direct Distinct Rates of Entry Into the Lytic Program in Sensory Neurons in vivo. Front Microbiol 2019; 10:1624. [PMID: 31396171 PMCID: PMC6668326 DOI: 10.3389/fmicb.2019.01624] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2019] [Accepted: 07/01/2019] [Indexed: 01/23/2023] Open
Abstract
Infection and life-long residence in the human nervous system is central to herpes simplex virus (HSV) pathogenesis. Access is gained through innervating axonal projections of sensory neurons. This distinct mode of entry separates the viral genome from tegument proteins, including the potent transactivator of viral IE genes, VP16. This, in turn, promotes a balance between lytic and latent infection which underlies the ability of the virus to invade, disseminate, and set up a large reservoir of latent infections. In the mouse ocular model, TG neurons marked as either “latent” or “lytic” at 48 h postinfection indicated that these programs were selected early and were considered distinct and mutually exclusive. More recently, a temporal analysis of viral program selection revealed a default latent-like state that begins at ~18 h postinfection and in individual neurons, precedes entry into the viral lytic cycle. Studies using refined viral mutants demonstrated that transition out of this latent program depended upon the transactivation function of VP16. Pursuit of the apparent incongruity between the established leaky-late kinetics of VP16 expression with a “preimmediate-early” function led to the discovery of an unrecognized regulatory feature of the HSV-1 VP16 promoter near/downstream of its TATA box. Among three potential sites identified was a putative Egr-1/Sp1 site. Here, we report that a refined mutation of this site, while having no impact on replication in cultured cells or cornea, resulted in ~100-fold reduction in lytic infection in TG in vivo. Notably, the HSV-2 VP16 promoter has 13 direct tandem-repeats upstream of its TATA box forming multiple potential overlapping Egr-1/Sp1 sites. Thus, despite different structures, these promoters might share function in directing the preimmediate-early VP16 protein expression. To test this, the HSV-1 VP16 promoter/5′UTR was replaced by the HSV-2 VP16 promoter/5′UTR in the HSV-1 backbone. Compared to the genomically repaired isolate, the HSV-2 VP16 promoter/5′UTR (1) accelerated the transition into the lytic cycle, and enhanced (2) virulence, and (3) entry into the lytic cycle following a reactivation stressor. These gain-of-function phenotypes support the hypothesis that the VP16 promoter regulates the latent/lytic boundary in neurons and that the HSV-1 and HSV-2 promoter/5′UTRs encode distinct thresholds for this transition.
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Affiliation(s)
- Richard L Thompson
- Department of Molecular Genetics, Biochemistry, and Microbiology, University of Cincinnati, Cincinnati, OH, United States
| | - Nancy M Sawtell
- Department of Pediatrics, Division of Infectious Diseases, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, United States
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5
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Parra E, Gutiérrez L, Ferreira J. Association of increased levels of TGF-β1 and p14ARF in prostate carcinoma cell lines overexpressing Egr-1. Oncol Rep 2014; 32:2191-8. [PMID: 25224321 DOI: 10.3892/or.2014.3472] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2014] [Accepted: 07/24/2014] [Indexed: 11/05/2022] Open
Abstract
The present study examined the effect of the overexpression of early growth response gene (Egr-1) on transforming growth factor β-1 (TGF-β1) and p14ARF levels, in PC-3 and LNCaP prostate carcinoma cell lines. Amplification of EGR-1, TGF-β1 and p14ARF were observed in the two cell lines treated with different stimuli and resulted in a corresponding mRNA and protein expression. The downregulation of TGF-β1 and the attenuation of p14ARF expression by siRNA against Egr-1 predominantly suggested that TGF-β1 and p14ARF may be regulated by the transcription factor EGR-1. A marginal attenuation of cell growth in PC-3 and LNCaP prostate carcinoma cell lines overexpressing p14ARF was observed. Cells transfected with Egr-1 wild-type were able to grow and avoid cell cycle arrest and apoptosis in the presence or absence of p14ARF. In addition, EGR-1 stimulated the expression of TGF β-l as well as the accumulation of the p14ARF proteins. The results suggested that TGF-β1 and p14ARF activities in the presence of EGR-1 overexpression can exist independently of the presence of cells carrying a mutant p53 (PC-3 cells) or cells carrying a wild‑type p53 (LNCaP cells). Thus, the effect of EGR-1 on the growth of prostate carcinoma cells may occur through multiple mechanisms, but be independent of p53 expression control.
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Affiliation(s)
- Eduardo Parra
- Laboratory of Experimental Biomedicine, University of Tarapaca, Campus Esmeralda, Iquique, Chile
| | - Luis Gutiérrez
- Faculty of Sciences, Arturo Prat University, Iquique, Chile
| | - Jorge Ferreira
- Programme of Molecular and Clinical Pharmacology, ICBM, Medical Faculty, University of Chile, Independencia, Santiago, Chile
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6
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Kosla J, Dvorakova M, Dvorak M, Cermak V. Effective myofibroblast dedifferentiation by concomitant inhibition of TGF-β signaling and perturbation of MAPK signaling. Eur J Cell Biol 2013; 92:363-73. [DOI: 10.1016/j.ejcb.2013.10.013] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2013] [Revised: 10/30/2013] [Accepted: 10/30/2013] [Indexed: 02/05/2023] Open
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Parra E, Gutiérrez L, Ferreira J. Increased expression of p21Waf1/Cip1 and JNK with costimulation of prostate cancer cell activation by an siRNA Egr-1 inhibitor. Oncol Rep 2013; 30:911-6. [PMID: 23715767 DOI: 10.3892/or.2013.2503] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2013] [Accepted: 03/03/2013] [Indexed: 11/06/2022] Open
Abstract
The p21Waf1/Cip1 protein (hereafter, p21) and the c‑Jun N-terminal kinase (JNK) are two well-characterized cell modulators that play a crucial role in cell differentiation, senescence and apoptosis. Here, we report that transcription of the p21Waf1/Cip1 and JNK-1 genes is affected by inhibition of the early growth response-1 (Egr-1) in response to a small interfering RNA [siRNA)-Egr-1] in LNCaP and PC-3 prostate carcinoma cell lines. The expression levels of protein were determined by western blotting, and apoptosis was measured by propidium iodide staining and flow cytometric analysis. Inhibition of Egr-1, p21 and JNK-1 was carried out by siRNAs. LNCaP and PC-3 cells exhibited readily detectable Egr-1, JNK and p21, even in low serum medium without the addition of other exogenous agents. The expression of Egr-1, p21 and JNK was strongly increased after treatment of the cells with TPA, tumor necrosis factor-α (TNF-α) or arsenite. Suppression of Egr-1 expression by siRNA abrogated the ability of TPA to induce Egr-1 and JNK-1 activities, moderately increasing the p21 activity and abrogating the anti-apoptotic effect of Egr-1 observed in the prostate cancer cell lines. Moreover, blockade of p21 and JNK was unable to decrease the activity of Egr-1, while siRNA against p21 abrogated the pro‑apoptotic effect of p21. The results demonstrated that Egr-1 acts as a key player in prostate tumor cell growth and survival, while p21 plays a key pro‑apoptotic role in LNCaP and PC-3 prostate carcinoma cell lines.
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Affiliation(s)
- Eduardo Parra
- Laboratory of Experimental Biomedicine, University of Tarapaca, Campus Esmeralda, Iquique, Chile.
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8
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Inhibition of matrix metalloproteinase-2 by halofuginone is mediated by the Egr1 transcription factor. Anticancer Drugs 2012; 23:1022-31. [DOI: 10.1097/cad.0b013e328357d186] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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9
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Fan YY, Ye GH, Lin KZ, Yu LS, Wu SZ, Dong MW, Han JG, Feng XP, Li XB. Time-dependent expression and distribution of Egr-1 during skeletal muscle wound healing in rats. J Mol Histol 2012; 44:75-81. [PMID: 22918836 DOI: 10.1007/s10735-012-9445-8] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2012] [Accepted: 08/14/2012] [Indexed: 12/26/2022]
Abstract
Recent studies have shown that early growth response factor-1 (Egr-1) plays an important role in regulation of inflammation and tissue repair, but little is known about its expression after trauma to skeletal muscles. A preliminary study on time-dependent expression and distribution of Egr-1 was performed by immunohistochemistry, immunofluorescence and Western blotting during skeletal muscle wound healing in rats. An animal model of skeletal muscle contusion was established in 45 Sprague-Dawley male rats. Samples were taken at 6 h, 12 h, 1 day, 3 days, 5 days, 7 days, 10 days, 14 days and 21 days post-injury, respectively (5 rats in each posttraumatic interval). 5 rats were employed as control. In the uninjured controls, Egr-1 positive staining was observed in the sarcoplasm and nuclei of normal myofibers. In wounded specimens, a small number of polymorphonuclear cells (PMNs), a number of mononuclear cells (MNCs), fibroblastic cells (FBCs) and regenerated multinucleated myotubes showed positive reaction for Egr-1 in contused zones. By morphometric analysis, an increase in Egr-1 expression was verified at inflammatory phase after contusion, which reached a peak in the regenerated phase overlapping with the fibrotic phase during skeletal muscle wound healing. The expression tendency was further confirmed by Western blotting assay. By immunofluorescent staining for co-localization, the Egr-1-positive MNCs and FBCs in wounds were identified as macrophages and myofibroblasts. The results demonstrate that the expression of Egr-1 is up-regulated and temporally distributed in certain cell types after trauma to skeletal muscles, which may be closely involved in inflammatory response, fibrotic repair and muscle regeneration during skeletal muscle wound healing.
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Affiliation(s)
- Yan-Yan Fan
- Department of Forensic Medicine, School of Basic Medical Science, Wenzhou Medical College, Higher Education District, Wenzhou, Zhejiang Province, People's Republic of China.
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Reumann MK, Strachna O, Yagerman S, Torrecilla D, Kim J, Doty SB, Lukashova L, Boskey AL, Mayer-Kuckuk P. Loss of transcription factor early growth response gene 1 results in impaired endochondral bone repair. Bone 2011; 49:743-52. [PMID: 21726677 PMCID: PMC3169183 DOI: 10.1016/j.bone.2011.06.023] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/15/2010] [Revised: 06/14/2011] [Accepted: 06/17/2011] [Indexed: 01/24/2023]
Abstract
Transcription factors that play a role in ossification during development are expected to participate in postnatal fracture repair since the endochondral bone formation that occurs in embryos is recapitulated during fracture repair. However, inherent differences exist between bone development and fracture repair, including a sudden disruption of tissue integrity followed by an inflammatory response. This raises the possibility that repair-specific transcription factors participate in bone healing. Here, we assessed the consequence of loss of early growth response gene 1 (EGR-1) on endochondral bone healing because this transcription factor has been shown to modulate repair in vascularized tissues. Model fractures were created in ribs of wild type (wt) and EGR-1(-/-) mice. Differences in tissue morphology and composition between these two animal groups were followed over 28 post fracture days (PFDs). In wt mice, bone healing occurred in healing phases characteristic of endochondral bone repair. A similar healing sequence was observed in EGR-1(-/-) mice but was impaired by alterations. A persistent accumulation of fibrin between the disconnected bones was observed on PFD7 and remained pronounced in the callus on PFD14. Additionally, the PFD14 callus was abnormally enlarged and showed increased deposition of mineralized tissue. Cartilage ossification in the callus was associated with hyper-vascularity and -proliferation. Moreover, cell deposits located in proximity to the callus within skeletal muscle were detected on PFD14. Despite these impairments, repair in EGR-1(-/-) callus advanced on PFD28, suggesting EGR-1 is not essential for healing. Together, this study provides genetic evidence that EGR-1 is a pleiotropic regulator of endochondral fracture repair.
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Affiliation(s)
- Marie K. Reumann
- Bone Cell Biology and Imaging Laboratory, Hospital for Special Surgery, New York
| | - Olga Strachna
- Bone Cell Biology and Imaging Laboratory, Hospital for Special Surgery, New York
| | - Sarah Yagerman
- Bone Cell Biology and Imaging Laboratory, Hospital for Special Surgery, New York
| | - Daniel Torrecilla
- Bone Cell Biology and Imaging Laboratory, Hospital for Special Surgery, New York
| | - Jihye Kim
- Bone Cell Biology and Imaging Laboratory, Hospital for Special Surgery, New York
| | - Steven B. Doty
- Analytical Microscopy Laboratory, Hospital for Special Surgery, New York
| | | | - Adele L. Boskey
- Mineralized Tissue Laboratory, Hospital for Special Surgery, New York
| | - Philipp Mayer-Kuckuk
- Bone Cell Biology and Imaging Laboratory, Hospital for Special Surgery, New York
- Corresponding author: Dr. Philipp Mayer-Kuckuk, Caspary Research Building, Rm. 623, Hospital for Special Surgery, 535 East 70 Street, New York, NY 10021, USA, Fax:(212) 774 7877,
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Gotoh S, Nakamura T, Kataoka T, Taketani S. Egr-1 regulates the transcriptional repression of mouse δ-aminolevulinic acid synthase 1 by heme. Gene 2011; 472:28-36. [DOI: 10.1016/j.gene.2010.10.008] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2010] [Revised: 10/19/2010] [Accepted: 10/22/2010] [Indexed: 10/18/2022]
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12
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Formononetin accelerates wound repair by the regulation of early growth response factor-1 transcription factor through the phosphorylation of the ERK and p38 MAPK pathways. Int Immunopharmacol 2011; 11:46-54. [DOI: 10.1016/j.intimp.2010.10.003] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2010] [Revised: 09/30/2010] [Accepted: 10/01/2010] [Indexed: 02/02/2023]
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13
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Patel N, Kalra VK. Placenta growth factor-induced early growth response 1 (Egr-1) regulates hypoxia-inducible factor-1alpha (HIF-1alpha) in endothelial cells. J Biol Chem 2010; 285:20570-9. [PMID: 20448047 DOI: 10.1074/jbc.m110.119495] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Leukotrienes, the lipid inflammatory products derived from arachidonic acid, are involved in the pathogenesis of respiratory and cardiovascular diseases and reactive airway disease in sickle cell disease. Placenta growth factor (PlGF), elaborated from erythroid cells, increased the mRNA expression of 5-lipoxygenase and 5-lipoxygenase-activating protein (FLAP) in human pulmonary microvascular endothelial cells. PlGF-induced both promoter activity and mRNA expression of hypoxia-inducible factor-1alpha (HIF-1alpha), which was abrogated by early growth response-1 (EGR-1) small interfering RNA. PlGF showed a temporal reciprocal relationship in the mRNA levels of EGR-1 and NAB2, the latter a repressor of Egr-1. Moreover, Nab2, but not mutant Nab2, significantly reduced promoter activity and mRNA expression of HIF-1alpha and also reduced expression of the HIF-1alpha target gene FLAP. Furthermore, overexpression of Egr-1 led to increased promoter activities for both HIF-1alpha and FLAP in the absence of PlGF. Additionally, the Egr-1-mediated induction of HIF-1alpha and FLAP promoters was reduced to basal levels by EGR-1 small interfering RNA. The binding of Egr-1 to HIF-1alpha promoter was corroborated by electrophoretic mobility shift assay and chromatin immunoprecipitation assay, which showed increased Egr-1 binding to the HIF-1alpha promoter in response to PlGF stimulation. These studies provide a novel mechanism for PlGF-mediated regulation of HIF-1alpha via Egr-1, which results in increased FLAP expression. This study provides a new therapeutic target, namely Egr-1, for attenuation of elevated leukotriene levels in patients with sickle cell disease and other inflammatory diseases.
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Affiliation(s)
- Nitin Patel
- Department of Biochemistry and Molecular Biology, Keck School of Medicine, University of Southern California, Los Angeles, CA 90033, USA
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14
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Gitenay D, Baron VT. Is EGR1 a potential target for prostate cancer therapy? Future Oncol 2009; 5:993-1003. [PMID: 19792968 DOI: 10.2217/fon.09.67] [Citation(s) in RCA: 93] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Prostate cancer is a major cause of cancer-related death in American men, for which finding new therapeutic strategies remains a challenge. Early growth response-1 (EGR1) is a transcription factor involved in cell proliferation and in the regulation of apoptosis. Although it has long been considered a tumor suppressor, a wealth of new evidence shows that EGR1 promotes the progression of prostate cancer. This review addresses the paradoxes of EGR1 function. While EGR1 mediates apoptosis in response to stress and DNA damage by regulating a tumor suppressor network, it also promotes the proliferation of prostate cancer cells by a mechanism that is not fully understood. Thus, EGR1 might be targeted for prostate cancer therapy either by ectopic expression in combination with radiotherapy or chemotherapy, or by direct inhibition for systemic treatment. Possible strategies to antagonize EGR1 function in a therapeutic setting are discussed.
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Affiliation(s)
- Delphine Gitenay
- The Vaccine Research Institute of San Diego, San Diego, CA 92121, USA. 19429708
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Bhattacharyya S, Wei J, Melichian DS, Milbrandt J, Takehara K, Varga J. The transcriptional cofactor nab2 is induced by tgf-Beta and suppresses fibroblast activation: physiological roles and impaired expression in scleroderma. PLoS One 2009; 4:e7620. [PMID: 19888474 PMCID: PMC2768752 DOI: 10.1371/journal.pone.0007620] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2009] [Accepted: 10/01/2009] [Indexed: 11/19/2022] Open
Abstract
By stimulating collagen synthesis and myofibroblasts differentiation, transforming growth factor-beta (TGF- beta) plays a pivotal role in tissue repair and fibrosis. The early growth response-1 (Egr-1) transcription factor mediates profibrotic TGF-beta responses, and its expression is elevated in biopsies from patients with scleroderma. NGF1-A-binding protein 2 (Nab2) is a conserved transcriptional cofactor that directly binds to Egr-1 and positively or negatively modulates Egr-1 target gene transcription. Despite the recognized importance of Nab2 in governing the intensity of Egr-1-dependent responses, the regulation and function of Nab2 in the context of fibrotic TGF-beta signaling is unknown. Here we show that TGF-beta caused a time-dependent stimulation of Nab2 protein and mRNA in normal fibroblasts. Ectopic expression of Nab2 in these cells blocked Egr-1-dependent transcriptional responses, and abrogated TGF-beta-induced stimulation of collagen synthesis and myofibroblasts differentiation. These inhibitory effects of Nab2 involved recruitment of the NuRD chromatin remodeling complex to the COL1A2 promoter and were accompanied by reduced histone H4 acetylation. Mice with targeted deletion of Nab2 displayed increased collagen accumulation in the dermis, and genetic or siRNA-mediated loss of Nab2 in fibroblasts was associated with constitutively elevated collagen synthesis and accentuation of Egr-1-dependent TGF-beta responses in vitro. Expression of Nab2 was markedly up-regulated in skin biopsies from patients with scleroderma, and was localized primarily to epidermal keratinocytes. In contrast, little Nab2 could be detected in dermal fibroblasts. These results identify Nab2 as a novel endogenous negative regulator of Egr-1-dependent TGF-beta signaling responsible for setting the intensity of fibrotic responses. Defective Nab2 expression or function in dermal fibroblasts might play a role in persistent fibrotic responses in scleroderma.
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Affiliation(s)
- Swati Bhattacharyya
- Division of Rheumatology, Northwestern University Feinberg School of Medicine, Chicago, Illinois, United States of America
| | - Jun Wei
- Division of Rheumatology, Northwestern University Feinberg School of Medicine, Chicago, Illinois, United States of America
| | - Denisa S. Melichian
- Division of Rheumatology, Northwestern University Feinberg School of Medicine, Chicago, Illinois, United States of America
| | - Jeffrey Milbrandt
- Division of Neurology, Washington University School of Medicine, St. Louis, Missouri, United States of America
| | | | - John Varga
- Division of Rheumatology, Northwestern University Feinberg School of Medicine, Chicago, Illinois, United States of America
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16
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Kubosaki A, Tomaru Y, Tagami M, Arner E, Miura H, Suzuki T, Suzuki M, Suzuki H, Hayashizaki Y. Genome-wide investigation of in vivo EGR-1 binding sites in monocytic differentiation. Genome Biol 2009; 10:R41. [PMID: 19374776 PMCID: PMC2688932 DOI: 10.1186/gb-2009-10-4-r41] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2009] [Revised: 04/06/2009] [Accepted: 04/19/2009] [Indexed: 01/10/2023] Open
Abstract
A Genome-wide analysis of EGR-1 binding sites reveals co-localization with CpG islands and histone H3 lysine 9 binding. SP-1 binding occupancies near EGR-1 binding sites are dramatically altered. Background Immediate early genes are considered to play important roles in dynamic gene regulatory networks following exposure to appropriate stimuli. One of the immediate early genes, early growth response gene 1 (EGR-1), has been implicated in differentiation of human monoblastoma cells along the monocytic commitment following treatment with phorbol ester. EGR-1 has been thought to work as a modifier of monopoiesis, but the precise function of EGR-1 in monocytic differentiation has not been fully elucidated. Results We performed the first genome-wide analysis of EGR-1 binding sites by chromatin immunoprecipitation with promoter array (ChIP-chip) and identified EGR-1 target sites in differentiating THP-1 cells. By combining the results with previously reported FANTOM4 data, we found that EGR-1 binding sites highly co-localized with CpG islands, acetylated histone H3 lysine 9 binding sites, and CAGE tag clusters. Gene Ontology (GO) analysis revealed enriched terms, including binding of molecules, in EGR-1 target genes. In addition, comparison with gene expression profiling data showed that EGR-1 binding influenced gene expression. Moreover, observation of in vivo occupancy changes of DNA binding proteins following PMA stimulation indicated that SP1 binding occupancies were dramatically changed near EGR-1 binding sites. Conclusions We conclude that EGR-1 mainly recognizes GC-rich consensus sequences in promoters of active genes. GO analysis and gene expression profiling data confirm that EGR-1 is involved in initiation of information transmission in cell events. The observations of in vivo occupancy changes of EGR-1 and SP1 suggest that several types of interplay between EGR-1 and other proteins result in multiple responses to EGR-1 downstream genes.
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Affiliation(s)
- Atsutaka Kubosaki
- RIKEN Omics Science Center, RIKEN Yokohama Institute 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama, Kanagawa 230-0045, Japan
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17
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Bedadala GR, Pinnoji RC, Hsia SCV. Early growth response gene 1 (Egr-1) regulates HSV-1 ICP4 and ICP22 gene expression. Cell Res 2009; 17:546-55. [PMID: 17502875 PMCID: PMC7092374 DOI: 10.1038/cr.2007.44] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
The molecular mechanisms mediating herpes simplex virus type 1 (HSV-1) gene silencing during latent infection are not clear. Five copies of early growth response gene 1 (Egr-1) binding elements were identified in the intron of HSV-1 ICP22 (infected cell protein No. 22) gene, leading to the hypothesis that Egr-1 binds to the viral genome and regulates the viral gene expression. Transient co-transfection assays indicated that Egr-1 negatively regulated the transcription of both full-length and intron-removed ICP22 promoters. The same assays also revealed that Egr-1 repressed ICP4 (infected cell protein No. 4) promoter activity in a dose-dependent manner but showed less inhibition when the intron was removed. Histone deacetylation was not involved in this regulation since histone deacetylase inhibitor trichostatin A did not exhibit any effect on Egr-1-mediated repression. Chromatin immunoprecipitation assays showed that Egr-1 reduced the binding of Sp1 to the promoters and that the co-repressor Nab2 (NGFI-A/EGR1-binding protein) was recruited to the proximity of ICP4 in the presence of Egr-1. These results suggested that the multifunctional transcription factor Egr-1 can repress HSV-1 immediate-early gene expression through the recruitment of co-repressor Nab2 and reduction of Sp1 occupancy, and thus may play a critical role in HSV-1 gene silencing during latency.
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Affiliation(s)
- Gautam R Bedadala
- Department of Basic Pharmaceutical Sciences, College of Pharmacy, The University of Louisiana at Monroe, 700 University Avenue, Monroe, 71209 LA USA
| | - Rajeswara C Pinnoji
- Department of Basic Pharmaceutical Sciences, College of Pharmacy, The University of Louisiana at Monroe, 700 University Avenue, Monroe, 71209 LA USA
| | - Shao-Chung V Hsia
- Department of Basic Pharmaceutical Sciences, College of Pharmacy, The University of Louisiana at Monroe, 700 University Avenue, Monroe, 71209 LA USA
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18
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Nozik-Grayck E, Suliman HB, Majka S, Albietz J, Van Rheen Z, Roush K, Stenmark KR. Lung EC-SOD overexpression attenuates hypoxic induction of Egr-1 and chronic hypoxic pulmonary vascular remodeling. Am J Physiol Lung Cell Mol Physiol 2008; 295:L422-30. [PMID: 18599502 DOI: 10.1152/ajplung.90293.2008] [Citation(s) in RCA: 94] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Although production of reactive oxygen species (ROS) such as superoxide (O(2)(.-)) has been implicated in chronic hypoxia-induced pulmonary hypertension (PH) and pulmonary vascular remodeling, the transcription factors and gene targets through which ROS exert their effects have not been completely identified. We used mice overexpressing the extracellular antioxidant enzyme extracellular superoxide dismutase (EC-SOD TG) to test the hypothesis that O(2)(.-) generated in the extracellular compartment under hypoxic conditions contributes to PH through the induction of the transcription factor, early growth response-1 (Egr-1), and its downstream gene target, tissue factor (TF). We found that chronic hypoxia decreased lung EC-SOD activity and protein expression in wild-type mice, but that EC-SOD activity remained five to seven times higher in EC-SOD TG mice under hypoxic conditions. EC-SOD overexpression attenuated chronic hypoxic PH, and vascular remodeling, measured by right ventricular systolic pressures, proliferation of cells in the vessel wall, muscularization of small pulmonary vessels, and collagen deposition. EC-SOD overexpression also prevented the early hypoxia-dependent upregulation of the redox-sensitive transcription factor Egr-1 and the procoagulant protein TF. These data provide the first evidence that EC-SOD activity is disrupted in chronic hypoxia, and increased EC-SOD activity can attenuate chronic hypoxic PH by limiting the hypoxic upregulation of redox-sensitive genes.
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Affiliation(s)
- Eva Nozik-Grayck
- Department of Pediatrics, Univ. of Colorado, Denver, 4200 E. 9th Ave., B131, Denver, CO 80262, USA.
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19
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Liu Y, Lu JB, Chen Q, Ye ZR. Involvement of MAPK/ERK kinase-ERK pathway in exogenous bFGF-induced Egr-1 binding activity enhancement in anoxia-reoxygenation injured astrocytes. Neurosci Bull 2008; 23:221-8. [PMID: 17687397 PMCID: PMC5550585 DOI: 10.1007/s12264-007-0033-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
Abstract
OBJECTIVE Intravenous administration of basic fibroblast growth factor (bFGF) is effective to reduce the volume of cerebral infract due to ischemia. This study was designed to investigate the molecular mechanism, especially the signal transduction pathways, involved in this protective role of bFGF. METHODS Anoxia-reoxygenation treated astrocytes were used to study the role of mitogen-activated protein kinase/extracellular signal-regulated kinase kinase (MAPK/ERK kinase, MEK)-ERK signaling pathway after exogenous bFGF administration by Western blot. Electrophoretic mobile shift assay was used to detect the binding activity of early growth response factor-1 (Egr-1), an important transcription factor for endogenous bFGF. RESULTS bFGF could protect some signal transduction proteins from the oxygen-derived free radicals induced degradation. ERK1/2 was activated and involved in Egr-1 binding activity enhancement induced by exogenous bFGF. CONCLUSION MEK-ERK MAPK cascade may be an important signal transduction pathway contributed to bFGF induced enhancement of Egr-1 binding activity in anoxia-reoxygenation injured astrocytes.
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Affiliation(s)
- Ying Liu
- Department of Pathology, Shanghai Medical College Fudan University, Shanghai, 200032 China
| | - Jin-Biao Lu
- Department of Pathology, Shanghai Medical College Fudan University, Shanghai, 200032 China
| | - Qi Chen
- Department of Pathology, Shanghai Medical College Fudan University, Shanghai, 200032 China
| | - Zhu-Rong Ye
- Department of Pathology, Shanghai Medical College Fudan University, Shanghai, 200032 China
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20
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Xu W, Chou CL, Sun H, Fujino H, Chen QM, Regan JW. FP prostanoid receptor-mediated induction of the expression of early growth response factor-1 by activation of a Ras/Raf/mitogen-activated protein kinase signaling cascade. Mol Pharmacol 2007; 73:111-8. [PMID: 17911534 DOI: 10.1124/mol.107.038778] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
FP prostanoid receptors are G-protein-coupled receptors whose physiological activator is prostaglandin-F(2alpha) (PGF(2alpha)). PGF(2alpha) has been implicated in wound healing and cardiac hypertrophy, which are both known to involve the induction of the immediate-early response gene, early growth response factor-1 (EGR-1). We hypothesized that activation of the human FP receptor by PGF(2alpha) could induce the expression of EGR-1 and found that 1 muM PGF(2alpha) produced a time-dependent induction of both mRNA and protein expression for EGR-1. This FP receptor-mediated induction of EGR-1 expression involved activation of the small GTPase Ras followed by activation of C-Raf and the mitogen-activated protein (MAP) kinase kinases 1 and 2 (MEK1/2). Thus, induction of EGR-1 expression by PGF(2alpha) was blocked using dominant-negative constructs of Ras and C-Raf and the Raf kinase inhibitor 4-(4-(3-(4-chloro-3-trifluoromethylphenyl)ureido)phenoxy)-pyridine-2-carboxyllic acid methyamide-4-methylbenzenesulfonate (BAY43-9006). Likewise, the MEK1/2 inhibitor 2'-amino-3'-methoxyflavone (PD98059) blocked the induction of EGR-1 expression by PGF(2alpha). FP receptor stimulation by PGF(2alpha) induced the phosphorylation of C-Raf, MEK1/2, and extracellular signal-regulated kinases 1 and 2, consistent with the activation of a MAP kinase signaling cascade. PGF(2alpha) was also found to induce the expression of EGR-1 in rat cardiomyocytes through the activation of endogenous FP receptors. This induction of EGR-1 expression in cardiomyocytes also involved the activation of Raf and MAP kinase signaling and was dependent on the activation of protein kinase C. This is the first report to show the regulation of EGR-1 expression after PGF(2alpha) activation of FP receptors and suggests that this could be an early event involved in wound healing and cardiac hypertrophy.
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Affiliation(s)
- Wei Xu
- Department of Pharmacology and Toxicology, College of Pharmacy/The University of Arizona, 1703 E. Mabel St., Tucson, AZ 85721-0207, USA
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Kasler HG, Verdin E. Histone deacetylase 7 functions as a key regulator of genes involved in both positive and negative selection of thymocytes. Mol Cell Biol 2007; 27:5184-200. [PMID: 17470548 PMCID: PMC1951960 DOI: 10.1128/mcb.02091-06] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Histone deacetylase 7 (HDAC7) is highly expressed in CD4(+)/CD8(+) thymocytes and functions as a signal-dependent repressor of gene transcription during T-cell development. In this study, we expressed HDAC7 mutant proteins in a T-cell line and use DNA microarrays to identify transcriptional targets of HDAC7 in T cells. The changes in gene expression levels were compared to differential gene expression profiles associated with positive and negative thymic selection. This analysis reveals that HDAC7 regulates an extensive set of genes that are differentially expressed during both positive and negative thymic selection. Many of these genes play important functional roles in thymic selection, primarily via modulating the coupling between antigen receptor engagement and downstream signaling events. Consistent with the model that HDAC7 may play an important role in both positive and negative thymic selection, the expression of distinct HDAC7 mutants or the abrogation of HDAC7 expression can either enhance or inhibit the signal-dependent differentiation of a CD4(+)/CD8(+) cell line.
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Affiliation(s)
- Herbert G Kasler
- Gladstone Institute of Virology and Immunology, 1650 Owens Street, San Francisco, CA 94158, USA
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22
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Carter JH, Tourtellotte WG. Early growth response transcriptional regulators are dispensable for macrophage differentiation. THE JOURNAL OF IMMUNOLOGY 2007; 178:3038-47. [PMID: 17312150 DOI: 10.4049/jimmunol.178.5.3038] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Early growth response (Egr) proteins comprise a family of transcriptional regulators (Egr1-4) that modulate gene expression involved in the growth and differentiation of many cell types. In particular, Egr1 is widely believed to have an essential role in regulating monocyte/macrophage differentiation. However, Egr1-deficient mice have normal numbers of functional macrophages, an observation that has led to the hypothesis that other Egr proteins may compensate for Egr1 function in vivo. We examined whether other Egr transcription factors have a functionally redundant role in monocyte/macrophage differentiation. Egr1 and Egr3 expression was found to be induced in myeloid cells when they were differentiated into macrophages by treatment with M-CSF, whereas Egr2 was minimally induced and Egr4 was not detected. In either Egr1/Egr3 or Egr1/Egr2 double homozygous mutant mice, macrophage differentiation and function remained unimpaired. Additionally, the expression of molecules that broadly inhibit Egr function failed to block commitment to the monocytic lineage or inhibit the maturation of monocyte precursors. Finally, several hemopoietic growth factors were found to induce Egr gene expression, indicating that Egr gene expression is not cell lineage specific. Taken together, these results demonstrate that Egr transcription factors are neither essential for nor specific to monocyte/macrophage differentiation.
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Affiliation(s)
- John H Carter
- Department of Pathology, Northwestern University, 330 E. Chicago Avenue, Chicago, IL 60611, USA
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Fukuda T, Kanomata K, Nojima J, Urakawa I, Suzawa T, Imada M, Kukita A, Kamijo R, Yamashita T, Katagiri T. FGF23 induces expression of two isoforms of NAB2, which are corepressors of Egr-1. Biochem Biophys Res Commun 2006; 353:147-51. [PMID: 17174939 DOI: 10.1016/j.bbrc.2006.12.011] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2006] [Accepted: 12/01/2006] [Indexed: 12/29/2022]
Abstract
Fibroblast growth factor 23 (FGF23) is a key humoral factor in phosphate homeostasis and skeletogenesis, though the nature of its intracellular signaling is still unclear. Recently, Egr-1, a zinc-finger transcription factor, was identified as an immediate early response gene of FGF23 in the kidney. We report here, that FGF23 induces not only Egr-1 but also two isoforms of NAB2, which are specific co-repressors of Egr-1. Both isoforms of NAB2 induced by FGF23 were localized in the nucleus and suppressed the transcriptional activity of Egr-1. A negative feedback loop established by Egr-1 and NAB2 may thus be involved in mediating the physiological effects of FGF23.
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Affiliation(s)
- Toru Fukuda
- Division of Pathophysiology, Research Center for Genomic Medicine, Saitama Medical University, Yamane 1397-1, Hidaka-shi, Saitama 350-1241, Japan
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Grotegut S, von Schweinitz D, Christofori G, Lehembre F. Hepatocyte growth factor induces cell scattering through MAPK/Egr-1-mediated upregulation of Snail. EMBO J 2006; 25:3534-45. [PMID: 16858414 PMCID: PMC1538570 DOI: 10.1038/sj.emboj.7601213] [Citation(s) in RCA: 264] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2006] [Accepted: 06/06/2006] [Indexed: 01/08/2023] Open
Abstract
Hepatocyte growth factor/scatter factor (HGF) exerts several functions in physiological and pathological processes, among them the induction of epithelial cell scattering and motility. Its pivotal role in angiogenesis, tumor progression, and metastasis is evident; however, the underlying molecular mechanisms are still poorly understood. Here, we demonstrate that HGF induces scattering of epithelial cells by upregulating the expression of Snail, a transcriptional repressor involved in epithelial-mesenchymal transition (EMT). Snail is required for HGF-induced cell scattering, since shRNA-mediated ablation of Snail expression prevents this process. HGF-induced upregulation of Snail transcription involves activation of the mitogen-activated protein kinase (MAPK) pathway and requires the activity of early growth response factor-1 (Egr-1). Upon induction by Egr-1, Snail represses the expression of E-cadherin and claudin-3 genes. It also binds to the Egr-1 promoter and represses Egr-1 transcription, thereby establishing a negative regulatory feedback loop. These findings indicate that Snail upregulation by HGF is mediated via the MAPK/Egr-1 signaling pathway and that both Snail and Egr-1 play a critical role in HGF-induced cell scattering, migration, and invasion.
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Affiliation(s)
- Stefan Grotegut
- Department of Clinical-Biological Sciences, Institute of Biochemistry and Genetics, Center of Biomedicine, University of Basel, Basel, Switzerland
| | | | - Gerhard Christofori
- Department of Clinical-Biological Sciences, Institute of Biochemistry and Genetics, Center of Biomedicine, University of Basel, Basel, Switzerland
- Department of Clinical-Biological Sciences, Institute of Biochemistry and Genetics, Center of Biomedicine, University of Basel, Mattenstrasse 28, 4058 Basel, Switzerland. Tel.: +41 61 267 3562; Fax: +41 61 267 3566; E-mail:
| | - François Lehembre
- Department of Clinical-Biological Sciences, Institute of Biochemistry and Genetics, Center of Biomedicine, University of Basel, Basel, Switzerland
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Srinivasan R, Mager GM, Ward RM, Mayer J, Svaren J. NAB2 Represses Transcription by Interacting with the CHD4 Subunit of the Nucleosome Remodeling and Deacetylase (NuRD) Complex. J Biol Chem 2006; 281:15129-37. [PMID: 16574654 DOI: 10.1074/jbc.m600775200] [Citation(s) in RCA: 87] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Early growth response (EGR) transactivators act as critical regulators of several physiological processes, including peripheral nerve myelination and progression of prostate cancer. The NAB1 and NAB2 (NGFI-A/EGR1-binding protein) transcriptional corepressors directly interact with three EGR family members (Egr1/NGFI-A/zif268, Egr2/Krox20, and Egr3) and repress activation of their target promoters. To understand the molecular mechanisms underlying NAB repression, we found that EGR activity is modulated by at least two repression domains within NAB2, one of which uniquely requires interaction with the CHD4 (chromodomain helicase DNA-binding protein 4) subunit of the NuRD (nucleosome remodeling and deacetylase) chromatin remodeling complex. Both NAB proteins can bind either CHD3 or CHD4, indicating that the interaction is conserved among these two protein families. Furthermore, we show that repression of the endogenous Rad gene by NAB2 involves interaction with CHD4 and demonstrate colocalization of NAB2 and CHD4 on the Rad promoter in myelinating Schwann cells. Finally, we show that interaction with CHD4 is regulated by alternative splicing of the NAB2 mRNA.
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Affiliation(s)
- Rajini Srinivasan
- Department of Comparative Biosciences, University of Wisconsin, Madison, WI 53706, USA
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26
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Braddock M. Euroconference on tissue repair and ulcer/wound healing: molecular mechanisms, therapeutic targets and future directions. Expert Opin Investig Drugs 2006; 14:743-9. [PMID: 16004601 DOI: 10.1517/13543784.14.6.743] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
The meeting was part of the Euroconference series organised at the Pasteur Institute in Paris. Comprising delegates from both academia and industry, it drew on expertise from many aspects of tissue repair in a wide range of human disease. The principal component of this report concerns progress with the therapeutic application of biological agents in promoting tissue repair, as gene therapeutics, monoclonal antibodies and therapeutic proteins. In addition, the effect of pioglitazone on the rate and quality of wound healing in diabetic rats is also reported.
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Affiliation(s)
- Martin Braddock
- Discovery Bioscience, AstraZeneca R&D Charnwood, Bakewell Road, Loughborough, Leicestershire, LE11 5RH, UK.
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27
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Abstract
The immediate-early gene product and zinc finger transcription factor early growth response (Egr)-1 plays a key master regulatory role in multiple cardiovascular pathological processes. This article reviews the amazing recent evidence implicating Egr-1 in atherosclerosis, intimal thickening after acute vascular injury, ischemic pathology, angiogenesis, allograft rejection, and cardiac hypertrophy.
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Affiliation(s)
- Levon M Khachigian
- Centre for Vascular Research, Department of Pathology, The University of New South Wales, The Prince of Wales Hospital, Sydney, Australia.
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28
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Fujita K, Komatsu K, Tanaka K, Ohshima S, Asami Y, Murata E, Akita M. An in vitro model for studying vascular injury after laser microdissection. Histochem Cell Biol 2005; 125:509-14. [PMID: 16292658 DOI: 10.1007/s00418-005-0106-9] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/11/2005] [Indexed: 11/25/2022]
Abstract
We have developed an in vitro model for studying vascular injury. After 7-10 days in a three-dimensional collagen gel culture, capillary-like tubes were formed in the collagen gels. We injured these capillary-like tubes with a laser microdissection system or a scrape method with razors and then examined the collagen gel culture by phase contrast and electron microscopy. After laser injury, profuse necrotic cells were observed around the injured capillary-like tubes and within the tubular lumen compared to the razor injury. We then isolated total RNA from these cultures and prepared cDNA for investigations by quantitative real-time reverse transcription polymerase chain reaction (RT-PCR). Quantitative real time RT-PCR revealed the up-regulation of transcription factor early growth response-1 (Egr-1) after both laser and razor injury, accompanied by the up-regulation of fibroblast growth factor-2 (FGF-2), a proangiogenic factor downstream of Egr-1. The effective laser energy is concentrated on the minute focal spot only. These methods provide a useful in vitro model for studying vascular injury.
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Affiliation(s)
- Keiko Fujita
- Department of Anatomy, Saitama Medical School, 38 Moroyama, Iruma-gun, 350-0495, Saitama, Japan.
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Lee YS, Jang HS, Kim JM, Lee JS, Lee JY, Li Kim K, Shin IS, Suh W, Choi JH, Jeon ES, Byun J, Kim DK. Adenoviral-mediated delivery of early growth response factor-1 gene increases tissue perfusion in a murine model of hindlimb ischemia. Mol Ther 2005; 12:328-36. [PMID: 16043101 DOI: 10.1016/j.ymthe.2005.03.027] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2004] [Revised: 03/14/2005] [Accepted: 03/21/2005] [Indexed: 11/29/2022] Open
Abstract
To test the hypothesis that overexpression of early growth response factor-1 (Egr-1) contributes to the revascularization of ischemic limbs, a constitutively active form of Egr-1 (Egr-1*) was made and evaluated in vitro and in vivo. Analyses of the transduced myocytes revealed significant upregulation of bFGF, PDGF-A, PDGF-B, IGF-II, and TGF-beta1. A coculture assay of the paracrine effects indicated that Ad-Egr-1* promoted proliferation and migration of endothelial cells. When Ad-Egr-1* was injected into the tibialis anterior muscle of mice, followed by explant culture in growth factor-reduced Matrigel, many capillary-like structures were observed in the Egr-1* group compared with minimal sprouting from the LacZ group, suggesting an angiogenic potential of Egr-1*. Next we evaluated Ad-Egr-1* in a murine model of hindlimb ischemia. Compared with slow revascularization in the control PBS or LacZ group, a rapid increase in tissue perfusion was observed in the Egr-1* group and the difference in flux ratio was statistically significant at day 7. In the injected muscle, expression of Egr-1*, upregulation of its target genes, and increased number of vessels staining positive for smooth muscle alpha-actin were observed. These results suggest that Egr-1 plays an important role in vascular recovery after occlusion and could be a potential target for therapeutic angiogenesis.
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Affiliation(s)
- Young-Sam Lee
- Department of Medicine, Samsung Medical Center, Samsung Biomedical Research Institute, Sungkyunkwan University School of Medicine, 50 Ilwon-dong, Kangnam-ku, Seoul 135-710, Korea
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30
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Mishra JP, Mishra S, Gee K, Kumar A. Differential involvement of calmodulin-dependent protein kinase II-activated AP-1 and c-Jun N-terminal kinase-activated EGR-1 signaling pathways in tumor necrosis factor-alpha and lipopolysaccharide-induced CD44 expression in human monocytic cells. J Biol Chem 2005; 280:26825-37. [PMID: 15923644 DOI: 10.1074/jbc.m500244200] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
CD44 plays a crucial role in cell migration, inflammation, and immune responses. Alteration in the levels of CD44 expression on monocytic cells by endotoxins and immunoregulatory cytokines may modulate the migration of immune cells to inflammatory sites and the development of immune responses. Lipopolysaccharide (LPS) and the proinflammatory cytokine, tumor necrosis factor-alpha (TNF-alpha), act as important regulators of CD44 expression in human monocytic cells. We previously demonstrated that the c-Jun N-terminal kinase (JNK), a mitogen-activated protein kinase (MAPK), differentially regulated LPS- but not TNF-alpha-induced CD44 expression in monocytic cells. In this study, our results suggest that the calcium signaling pathway, in particular calmodulin (CaM) and CaM-dependent protein kinase II (CaMK-II), is involved in TNF-alpha- but not LPS-induced CD44 expression. CD44 promoter analysis suggested the participation of distinct transcription factors AP-1 and Egr-1 in TNF-alpha- and LPS-induced CD44 expression, respectively. Furthermore, TNF-alpha-induced CD44 expression was regulated by AP-1 through the activation of the CaMK-II pathway, whereas LPS-induced CD44 transcription was regulated specifically by Egr-1 through JNK activation. Overall, the results suggest the involvement of two distinct and independent signaling pathways involved in the regulation of CD44 transcription that may represent potential targets for anti-inflammatory agents capable of inhibiting CD44-mediated cell migration.
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Affiliation(s)
- Jyoti P Mishra
- Department of Pathology and Laboratory Medicine, University of Ottawa, Ontario, Canada
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31
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Goldhar AS, Vonderhaar BK, Trott JF, Hovey RC. Prolactin-induced expression of vascular endothelial growth factor via Egr-1. Mol Cell Endocrinol 2005; 232:9-19. [PMID: 15737464 DOI: 10.1016/j.mce.2005.01.005] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/23/2003] [Revised: 01/16/2005] [Accepted: 01/18/2005] [Indexed: 11/18/2022]
Abstract
Angiogenesis is a dynamic process regulated by both local and systemic factors. Among these is vascular endothelial growth factor (VEGF), a potent effector of angiogenesis and vascular permeability. Previously we showed that VEGF is temporally and spatially regulated in the mouse mammary gland during development and lactation. Given the functions of prolactin (PRL) during these stages and the supporting role of the vasculature, we investigated the regulation of VEGF by PRL. Treatment of HC11 mouse mammary epithelial and Nb2 rat lymphoma cells with PRL induced VEGF expression. Deletion and mutation analysis identified a GC-rich region in the proximal region of the VEGF promoter that constitutively bound Sp1 and PRL-induced Egr-1. These sites conferred PRL-responsiveness leading to increased VEGF transcription. The induction of VEGF by PRL was PRL receptor-, Jak2- and MAP kinase kinase-dependent. Our results indicate that PRL induces VEGF expression through Egr-1, and implicates VEGF as an intermediary of PRL-regulated angiogenesis.
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Affiliation(s)
- Anita S Goldhar
- Mammary Biology and Tumorigenesis Laboratory, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892-1402, USA
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Neuhaus T, Stier S, Totzke G, Gruenewald E, Fronhoffs S, Sachinidis A, Vetter H, Ko YD. Stromal cell-derived factor 1alpha (SDF-1alpha) induces gene-expression of early growth response-1 (Egr-1) and VEGF in human arterial endothelial cells and enhances VEGF induced cell proliferation. Cell Prolif 2003; 36:75-86. [PMID: 12680875 PMCID: PMC6496392 DOI: 10.1046/j.1365-2184.2003.00262.x] [Citation(s) in RCA: 59] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Stromal cell-derived factor-1 (SDF-1), mainly known as a chemotactic factor for haematopoietic progenitor cells, also provides angiogenetic potency. Since the intracellular signalling of SDF-1-induced neovascularization remains unclear, we studied in human umbilical arterial endothelial cells (HUAEC) the influence of SDF-1alpha on induction of the genes of early growth response-1 (Egr-1) and VEGF, as well as the activation of extracellular regulated kinases (ERK) 1/2, which are all known to be involved in endothelial cell proliferation. We found a time-dependent induction of Egr-1 and VEGF mRNA expression and phosphorylation of ERK1/2 by SDF-1alpha. Furthermore, we demonstrated that Egr-1 expression is dependent on ERK 1/2 activation. Finally, we tried to confirm the relevance of the induced gene expression by detecting the [3H]thymidine incorporation as a marker for cell proliferation in HUAEC after stimulation with SDF-1alpha alone or together with VEGF. This particular test showed, that SDF-1alpha alone has no effect, but is able to significantly enhance VEGF induced DNA synthesis. In summary, SDF-1alpha is involved in different steps of endothelial cell proliferation, but, since Egr-1 and VEGF offer different functions, it may also play a so far undefined role on other conditions of the endothelium.
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Affiliation(s)
- Thomas Neuhaus
- Medizinische Universitäts-Poliklinik Bonn, Bonn, Germany
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Lucerna M, Mechtcheriakova D, Kadl A, Schabbauer G, Schäfer R, Gruber F, Koshelnick Y, Müller HD, Issbrücker K, Clauss M, Binder BR, Hofer E. NAB2, a corepressor of EGR-1, inhibits vascular endothelial growth factor-mediated gene induction and angiogenic responses of endothelial cells. J Biol Chem 2003; 278:11433-40. [PMID: 12427750 DOI: 10.1074/jbc.m204937200] [Citation(s) in RCA: 78] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
In this study we have investigated the role of a specific corepressor of EGR-1, NAB2, to down-regulate vascular endothelial growth factor (VEGF)-induced gene expression in endothelial cells and to inhibit angiogenesis. Firstly, we show a reciprocal regulation of EGR-1 and NAB2 following VEGF treatment. During the initial phase EGR-1 is rapidly induced and NAB2 levels are down-regulated. This is followed by a reduction of EGR-1 and a concomitant increase of NAB2. Secondly, using the tissue factor gene as a readout for VEGF-induced and EGR-1-regulated gene expression we demonstrate that NAB2 can completely block VEGF-induced tissue factor reporter gene activity. Thirdly, by adenovirus-mediated expression we show that NAB2 inhibits up-regulation of tissue factor, VEGF receptor-1, and urokinase plasminogen activator mRNAs even when a combination of VEGF and bFGF is used for induction. In addition, NAB2 overexpression significantly reduced tubule and sprout formation in two different in vitro angiogenesis assays and largely prevented the invasion of cells and formation of vessel-like structures in the murine Matrigel model. These data suggest that NAB2 regulation represents a mechanism to guarantee transient EGR-1 activity following exposure of endothelial cells to VEGF and that NAB2 overexpression could be used to inhibit signals involved in the early phase of angiogenesis.
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Affiliation(s)
- Markus Lucerna
- Department of Vascular Biology and Thrombosis Research, Vienna International Research Cooperation Center, University of Vienna, Brunnerstrasse 59, A-1235 Vienna, Austria
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Abstract
Immature double positive (DP) thymocytes bearing a T cell receptor (TCR) that interacts with self-major histocompatibility complex (MHC) molecules receive signals that induce either their differentiation (positive selection) or apoptosis (negative selection). Furthermore, those cells that are positively selected develop into two different lineages, CD4 or CD8, depending on whether their TCRs bind to MHC class II or I, respectively. Positive selection therefore involves rescue from the default fate (death), lineage commitment, and progression to the single positive (SP) stage. These are probably temporally distinct events that may require both unique and overlapping signals. Work in the past several years has started to unravel the signaling networks that control these processes. One of the first pathways identified as important for positive selection was Ras and its downstream effector, the Erk mitogen-activated protein kinase (MAPK) cascade. In this review we examine the factors that connect the TCR to the Ras/Erk cascade in DP thymocytes, as well as what we know about the downstream effectors of the Ras/Erk cascade important for positive selection. We also consider the possible role of this cascade in CD4/CD8 lineage development, and the possible interactions of the Ras/Erk cascade with Notch during these cell fate determination processes.
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Affiliation(s)
- José Alberola-Ila
- Division of Biology, California Institute of Technology, Pasadena, CA 91125, USA.
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35
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Haas TL. Molecular control of capillary growth in skeletal muscle. CANADIAN JOURNAL OF APPLIED PHYSIOLOGY = REVUE CANADIENNE DE PHYSIOLOGIE APPLIQUEE 2002; 27:491-515. [PMID: 12429896 DOI: 10.1139/h02-027] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Angiogenesis, the growth of new capillaries, enhances the oxygen delivery capacity of an existing vascular network. This adaptation is a well-documented occurrence in exercising skeletal muscle. The purpose of this review is to summarize our current understanding of the various stimuli that are involved in the initiation of capillary growth in skeletal muscle. The roles of humoral and mechanical signals in the cellular regulation of several key angiogenic players, vascular endothelial cell growth factor and matrix metalloproteinases, will be discussed. Evidence will be presented supporting the existence of angiogenesis processes that are distinct from the "classically" defined process. Determining how specific angiogenic stimuli can initiate unique patterns of capillary growth will provide insight into the complex task of developing effective pro-angiogenic therapies.
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Affiliation(s)
- Tara L Haas
- Department of Kinesiology and Health Sciences, York University, Toronto, Ontario, Canada
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Abstract
In the United States, between 40 and 90 million hospital days are lost per year as a result of trauma and surgical procedures which result in the loss of functional tissue. This is estimated to cost the economy and healthcare providers in excess of US$ 500 billion, a figure that is increasing because of extending population lifespan. Tissue engineering and gene therapies are radical new treatments that are aimed at tissue regeneration ranging from dermal, osteal and occular repair to the replacement of failing tissue with entire biosynthetic organs. Over the last decade, numerous proteins have been identified that are able to direct the synthesis of new tissue. Such proteins include growth factors, cytokines and, more recently, transcription factors.
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Affiliation(s)
- M Braddock
- Disease Cell Biology Unit, GlaxoWellcome Medicines Research Centre, Stevenage, Herts, UK.
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