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Ugwu N, Atzmony L, Ellis KT, Panse G, Jain D, Ko CJ, Nassiri N, Choate KA. Cutaneous and hepatic vascular lesions due to a recurrent somatic GJA4 mutation reveal a pathway for vascular malformation. HGG ADVANCES 2021; 2. [PMID: 33912852 PMCID: PMC8078848 DOI: 10.1016/j.xhgg.2021.100028] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
The term “cavernous hemangioma” has been used to describe vascular anomalies with histology featuring dilated vascular spaces, vessel walls consisting mainly of fibrous stromal bands lined by a layer of flattened endothelial cells, and an irregular outer rim of interrupted smooth muscle cells. Hepatic hemangiomas (HHs) and cutaneous venous malformations (VMs) share this histologic pattern, and we examined lesions in both tissues to identify genetic drivers. Paired whole-exome sequencing (WES) of lesional tissue and normal liver in HH subjects revealed a recurrent GJA4 c.121G>T (p.Gly41Cys) somatic mutation in four of five unrelated individuals, and targeted sequencing in paired tissue from 9 additional HH individuals identified the same mutation in 8. In cutaneous lesions, paired targeted sequencing in 5 VMs and normal epidermis found the same GJA4 c.121G>T (p.Gly41Cys) somatic mutation in three. GJA4 encodes gap junction protein alpha 4, also called connexin 37 (Cx37), and the p.Gly41Cys mutation falls within the first transmembrane domain at a residue highly conserved among vertebrates. We interrogated the impact of the Cx37 mutant via lentiviral transduction of primary human endothelial cells. We found that the mutant induced changes in cell morphology and activated serum/glucocorticoid-regulated kinase 1 (SGK1), a serine/threonine kinase known to regulate cell proliferation and apoptosis, via non-canonical activation. Treatment with spironolactone, an inhibitor of angiogenesis, suppressed mutant SGK1 activation and reversed changes in cell morphology. These findings identify a recurrent somatic GJA4 c.121G>T mutation as a driver of hepatic and cutaneous VMs, revealing a new pathway for vascular anomalies, with spironolactone a potential pathogenesis-based therapy.
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Affiliation(s)
- Nelson Ugwu
- Department of Dermatology, School of Medicine, Yale University, New Haven, CT 06510, USA.,Vascular Malformations Program (VaMP), Yale New Haven Hospital, New Haven, CT, USA
| | - Lihi Atzmony
- Department of Dermatology, School of Medicine, Yale University, New Haven, CT 06510, USA.,Department of Genetics, Yale University School of Medicine, New Haven, CT, USA.,Department of Pathology, Yale University School of Medicine, New Haven, CT, USA.,Vascular Malformations Program (VaMP), Yale New Haven Hospital, New Haven, CT, USA
| | - Katharine T Ellis
- Department of Genetics, Yale University School of Medicine, New Haven, CT, USA
| | - Gauri Panse
- Department of Dermatology, School of Medicine, Yale University, New Haven, CT 06510, USA.,Department of Pathology, Yale University School of Medicine, New Haven, CT, USA.,Vascular Malformations Program (VaMP), Yale New Haven Hospital, New Haven, CT, USA
| | - Dhanpat Jain
- Department of Pathology, Yale University School of Medicine, New Haven, CT, USA.,Department of Internal Medicine, Yale University School of Medicine, New Haven, CT, USA
| | - Christine J Ko
- Department of Dermatology, School of Medicine, Yale University, New Haven, CT 06510, USA.,Department of Pathology, Yale University School of Medicine, New Haven, CT, USA.,Vascular Malformations Program (VaMP), Yale New Haven Hospital, New Haven, CT, USA
| | - Naiem Nassiri
- Division of Vascular and Endovascular Surgery, Department of Surgery, Yale University School of Medicine, New Haven, CT 06510, USA.,Vascular Malformations Program (VaMP), Yale New Haven Hospital, New Haven, CT, USA.,Senior author
| | - Keith A Choate
- Department of Dermatology, School of Medicine, Yale University, New Haven, CT 06510, USA.,Department of Genetics, Yale University School of Medicine, New Haven, CT, USA.,Department of Pathology, Yale University School of Medicine, New Haven, CT, USA.,Vascular Malformations Program (VaMP), Yale New Haven Hospital, New Haven, CT, USA.,Senior author
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2
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Chu D, Nguyen A, Smith SS, Vavrušová Z, Schneider RA. Stable integration of an optimized inducible promoter system enables spatiotemporal control of gene expression throughout avian development. Biol Open 2020; 9:bio055343. [PMID: 32917762 PMCID: PMC7561481 DOI: 10.1242/bio.055343] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2020] [Accepted: 08/27/2020] [Indexed: 01/18/2023] Open
Abstract
Precisely altering gene expression is critical for understanding molecular processes of embryogenesis. Although some tools exist for transgene misexpression in developing chick embryos, we have refined and advanced them by simplifying and optimizing constructs for spatiotemporal control. To maintain expression over the entire course of embryonic development we use an enhanced piggyBac transposon system that efficiently integrates sequences into the host genome. We also incorporate a DNA targeting sequence to direct plasmid translocation into the nucleus and a D4Z4 insulator sequence to prevent epigenetic silencing. We designed these constructs to minimize their size and maximize cellular uptake, and to simplify usage by placing all of the integrating sequences on a single plasmid. Following electroporation of stage HH8.5 embryos, our tetracycline-inducible promoter construct produces robust transgene expression in the presence of doxycycline at any point during embryonic development in ovo or in culture. Moreover, expression levels can be modulated by titrating doxycycline concentrations and spatial control can be achieved using beads or gels. Thus, we have generated a novel, sensitive, tunable, and stable inducible-promoter system for high-resolution gene manipulation in vivo.
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Affiliation(s)
- Daniel Chu
- Department of Orthopaedic Surgery, University of California at San Francisco, 513 Parnassus Avenue, S-1164, San Francisco, CA 94143-0514, USA
| | - An Nguyen
- Department of Orthopaedic Surgery, University of California at San Francisco, 513 Parnassus Avenue, S-1164, San Francisco, CA 94143-0514, USA
| | - Spenser S Smith
- Department of Orthopaedic Surgery, University of California at San Francisco, 513 Parnassus Avenue, S-1164, San Francisco, CA 94143-0514, USA
| | - Zuzana Vavrušová
- Department of Orthopaedic Surgery, University of California at San Francisco, 513 Parnassus Avenue, S-1164, San Francisco, CA 94143-0514, USA
| | - Richard A Schneider
- Department of Orthopaedic Surgery, University of California at San Francisco, 513 Parnassus Avenue, S-1164, San Francisco, CA 94143-0514, USA
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Das AT, Tenenbaum L, Berkhout B. Tet-On Systems For Doxycycline-inducible Gene Expression. Curr Gene Ther 2017; 16:156-67. [PMID: 27216914 PMCID: PMC5070417 DOI: 10.2174/1566523216666160524144041] [Citation(s) in RCA: 225] [Impact Index Per Article: 32.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2015] [Revised: 05/03/2016] [Accepted: 05/03/2016] [Indexed: 11/22/2022]
Abstract
The tetracycline-controlled Tet-Off and Tet-On gene expression systems are used to regulate the activity of genes in eukaryotic cells in diverse settings, varying from basic biological research to biotechnology and gene therapy applications. These systems are based on regulatory elements that control the activity of the tetracycline-resistance operon in bacteria. The Tet-Off system allows silencing of gene expression by administration of tetracycline (Tc) or tetracycline-derivatives like doxycycline (dox), whereas the Tet-On system allows activation of gene expression by dox. Since the initial design and construction of the original Tet-system, these bacterium-derived systems have been significantly improved for their function in eukaryotic cells. We here review how a dox-controlled HIV-1 variant was designed and used to greatly improve the activity and dox-sensitivity of the rtTA transcriptional activator component of the Tet-On system. These optimized rtTA variants require less dox for activation, which will reduce side effects and allow gene control in tissues where a relatively low dox level can be reached, such as the brain.
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Affiliation(s)
- Atze T Das
- Laboratory of Experimental Virology, Academic Medical Center, Meibergdreef 15, 1105 AZ Amsterdam, The Netherlands.
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Das AT, Zhou X, Metz SW, Vink MA, Berkhout B. Selecting the optimal Tet-On system for doxycycline-inducible gene expression in transiently transfected and stably transduced mammalian cells. Biotechnol J 2015; 11:71-9. [PMID: 26333522 DOI: 10.1002/biot.201500236] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2015] [Revised: 06/14/2015] [Accepted: 09/02/2015] [Indexed: 11/05/2022]
Abstract
The doxycycline (dox)-inducible Tet-On system is widely used to control gene expression in mammalian cells. This system is based on the bacterial Tet operon, which has been modified and improved for its function in eukaryotic cells. To identify the optimal system for different applications, we compared Tet-On variants in frequently used cell types that were either transiently transfected with the relevant plasmids or stably transduced with an "all-in-one" lentiviral vector. The V10 variant performed optimally in the transiently transfected cells and demonstrated no background activity without dox, high dox-induced activity and the highest fold-induction. Because of its very high dox-sensitivity, the V16 system may be preferred if only low intracellular dox concentrations can be reached. V16 performed optimally in the transduced cells and demonstrated the highest activity and dox-sensitivity without background activity. Moreover, V16 demonstrated more robust induction of gene expression after a latency period without dox. This study provides important findings for choosing the optimal Tet-On system for diverse cell culture settings. V10 is the best system for most applications in which the DNA is episomally present in cells, whereas V16 may be optimal when the Tet-On components are stably integrated in the cellular genome.
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Affiliation(s)
- Atze T Das
- Laboratory of Experimental Virology, Department of Medical Microbiology, Center for Infection and Immunity Amsterdam (CINIMA), Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands.
| | - Xue Zhou
- Laboratory of Experimental Virology, Department of Medical Microbiology, Center for Infection and Immunity Amsterdam (CINIMA), Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Stefan W Metz
- Laboratory of Experimental Virology, Department of Medical Microbiology, Center for Infection and Immunity Amsterdam (CINIMA), Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Monique A Vink
- Laboratory of Experimental Virology, Department of Medical Microbiology, Center for Infection and Immunity Amsterdam (CINIMA), Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Ben Berkhout
- Laboratory of Experimental Virology, Department of Medical Microbiology, Center for Infection and Immunity Amsterdam (CINIMA), Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
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Lachmann N, Brennig S, Hillje R, Schermeier H, Phaltane R, Dahlmann J, Gruh I, Heinz N, Schiedlmeier B, Baum C, Moritz T. Tightly regulated 'all-in-one' lentiviral vectors for protection of human hematopoietic cells from anticancer chemotherapy. Gene Ther 2015; 22:883-92. [PMID: 26125609 DOI: 10.1038/gt.2015.61] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2014] [Revised: 06/09/2015] [Accepted: 06/18/2015] [Indexed: 01/12/2023]
Abstract
Successful application of gene therapy strategies may require stringently regulated transgene expression. Along this line, we describe a doxycycline (Dox)-inducible 'all-in-one' lentiviral vector design using the pTET-T11 (TII) minimal-promoter and a reverse transactivator protein (rtTA2S-M2) driven by the phosphoglycerate kinase promoter allowing for tight regulation of transgene expression (Lv.TII vectors). Vector design was evaluated in human hematopoietic cells in the context of cytidine deaminase (hCDD)-based myeloprotective gene therapy. Upon Dox administration, a rapid (16-24 h) and dose-dependent (>0.04 μg ml(-1) Dox) onset of transgene expression was detected in Lv.TII.CDD gene-modified K562 cells as well as in primary human CD34(+) hematopoietic cells. Importantly, in both cell models low background transgene expression was observed in the absence of Dox. Functionality of Dox-inducible hCDD expression was demonstrated by >10-fold increase in cytosine arabinoside (1-β-d-arabinofuranosylcytosine, Ara-C) resistance of Lv.TII.CDD-transduced K562 cells. In addition, Lv.TII.CDD-transduced CD34(+)-derived myeloid cells were protected from up to 300 nm Ara-C (control affected from 50 nm onwards). These data clearly demonstrate the suitability of our self-inactivating lentiviral vector to induce robust, tightly regulated transgene expression in human hematopoietic cells with minimal background activity and highlight the potential of our construct in myeloprotective gene therapy strategies.
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Affiliation(s)
- N Lachmann
- Reprogramming and Gene Therapy Group, REBIRTH Cluster of Excellence, Hannover Medical School, Hannover, Germany.,Institute of Experimental Hematology, Hannover Medical School, Hannover, Germany
| | - S Brennig
- Reprogramming and Gene Therapy Group, REBIRTH Cluster of Excellence, Hannover Medical School, Hannover, Germany.,Institute of Experimental Hematology, Hannover Medical School, Hannover, Germany
| | - R Hillje
- Reprogramming and Gene Therapy Group, REBIRTH Cluster of Excellence, Hannover Medical School, Hannover, Germany.,Institute of Experimental Hematology, Hannover Medical School, Hannover, Germany
| | - H Schermeier
- Reprogramming and Gene Therapy Group, REBIRTH Cluster of Excellence, Hannover Medical School, Hannover, Germany.,Institute of Experimental Hematology, Hannover Medical School, Hannover, Germany
| | - R Phaltane
- Reprogramming and Gene Therapy Group, REBIRTH Cluster of Excellence, Hannover Medical School, Hannover, Germany.,Institute of Experimental Hematology, Hannover Medical School, Hannover, Germany
| | - J Dahlmann
- Leibniz Research Laboratories for Biotechnology and Artificial Organs (LEBAO), Department of Cardiothoracic, Transplantation and Vascular Surgery, Hannover Medical School, Hannover, Germany
| | - I Gruh
- Leibniz Research Laboratories for Biotechnology and Artificial Organs (LEBAO), Department of Cardiothoracic, Transplantation and Vascular Surgery, Hannover Medical School, Hannover, Germany
| | - N Heinz
- LOEWE-Research Group for (targeted) Gene Modification in Stem Cells, Paul-Ehrlich-Institute, Langen, Germany
| | - B Schiedlmeier
- Institute of Experimental Hematology, Hannover Medical School, Hannover, Germany
| | - C Baum
- Institute of Experimental Hematology, Hannover Medical School, Hannover, Germany
| | - T Moritz
- Reprogramming and Gene Therapy Group, REBIRTH Cluster of Excellence, Hannover Medical School, Hannover, Germany.,Institute of Experimental Hematology, Hannover Medical School, Hannover, Germany
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Yang T, Burrows C, Park JH. Development of a doxycycline-inducible lentiviral plasmid with an instant regulatory feature. Plasmid 2014; 72:29-35. [PMID: 24727543 DOI: 10.1016/j.plasmid.2014.04.001] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2013] [Revised: 03/23/2014] [Accepted: 04/01/2014] [Indexed: 12/19/2022]
Abstract
Lentiviruses provide highly efficient gene delivery vehicles in both dividing and non-dividing cells. Inducible gene expression systems often employ a specific cell line that constitutively expresses a regulatory protein for transgene expression. As one of such inducible expression systems the Tet-On system uses a cell line expressing reverse tetracycline-responsive transcriptional activator (rtTA). The rtTA protein binds to the tetracycline-responsive element (TRE) in the promoter and activates transcription of a transgene in a doxycycline-dependent manner. To establish a universal and instant regulatory system without generating Tet-On cell lines, the cDNAs of rtTA and a testing target gene (PPM1B) were cloned in the bi-directional TRE-containing promoters. Here, we examined whether a basal leaky expression of rtTA allows instantly inducible expression of both rtTA itself and the target gene, PPM1B in a single plasmid using the two mini-CMV promoters. Transient transfection of the lentiviral plasmids into human embryonic kidney HEK293T cells showed a significant induction of PPM1B expression in response to doxycycline, suggesting that these lentiviral plasmids can be used as an instantly inducible mammalian expression vector. However, the expression of rtTA by lentiviral transduction shows a minimal expression without a consistent response to doxycycline, suggesting that the utility of these lentiviral vectors is limited. A potential solution to overcome lentiviral transgene inactivation is proposed.
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Affiliation(s)
- Tian Yang
- Institute of Fundamental Sciences, Massey University, Palmerston North, New Zealand; Institute of Somatology, Nanjing Medical University, 140 Hanzhong Road, Nanjing, Jiangsu 210029, PR China
| | - Christopher Burrows
- Institute of Fundamental Sciences, Massey University, Palmerston North, New Zealand
| | - Jeong Hyeon Park
- Institute of Fundamental Sciences, Massey University, Palmerston North, New Zealand.
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Delerue F, White M, Ittner LM. Inducible, tightly regulated and non-leaky neuronal gene expression in mice. Transgenic Res 2013; 23:225-33. [PMID: 24214494 DOI: 10.1007/s11248-013-9767-7] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2013] [Accepted: 10/28/2013] [Indexed: 11/25/2022]
Abstract
The Tetracycline (Tet)-controlled inducible system is the most widely used reversible system for transgene expression in mice with over 500 lines created to date. Although this system has been optimized over the years, it still has limitations such as residual transgene expression when turned off, referred to as leakiness. Here, we present a series of new Tet-OFF transgenic mice based on the second generation tetracycline-responsive transactivator system. The tTA-Advanced (tTA2(S)) is expressed under control of the neuron-specific Thy1.2 promoter (Thy-OFF), to regulate expression in the mouse brain. In addition, we generated a lacZ reporter line, utilizing the P tight Tet-responsive promoter (P(tight)-lacZ), to test our system. Two Thy-OFF transgenic lines displaying two distinct patterns of expression were selected. Oral doxycycline treatment of Thy-OFF/P tight-lacZ mice demonstrated tight transgene regulation with no leak expression. These new Thy-OFF mice are valuable for studies in a broad range of neurodegenerative diseases such as Alzheimer's disease and related forms of dementia, where control of transgene expression is critical to understanding mechanisms underlying the disease. Furthermore, P tight-lacZ reporter mice may be widely applicable.
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Affiliation(s)
- Fabien Delerue
- Transgenic Animal Unit, School of Medical Science, University of New South Wales, Sydney, NSW, 2052, Australia
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