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Duran AG, Schwestka M, Nazari-Shafti TZ, Neuber S, Stamm C, Gossen M. Limiting Transactivator Amounts Contribute to Transgene Mosaicism in Tet-On All-in-One Systems. ACS Synth Biol 2022; 11:2623-2635. [PMID: 35815862 DOI: 10.1021/acssynbio.2c00036] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
MicroRNAs play an essential role in cell homeostasis and have been proposed as therapeutic agents. One strategy to deliver microRNAs is to genetically engineer target cells to express microRNAs of interest. However, to control dosage and timing, as well as to limit potential side-effects, microRNAs' expression should ideally be under exogenous, inducible control. Conditional expression of miRNA-based short hairpin RNAs (shRNAmirs) via gene regulatory circuits such as the Tet-system is therefore a promising strategy to control shRNAmirs' expression in research and therapy. Single vector approaches like Tet-On all-in-one designs are more compatible with potential clinical applications by providing the Tet-On system components in a single round of genetic engineering. However, all-in-one systems often come at the expense of heterogeneous and unstable expression. In this study, we aimed to understand the causes that lead to such erratic transgene expression. By using a reporter cell, we found that the degree of heterogeneity mostly correlated with reverse tetracycline transactivator (rtTA) expression levels. Moreover, the targeted integration of a potent rtTA expression cassette into a genomic safe harbor locus functionally rescued previously silenced rtTA-responsive transcription units. Overall, our results suggest that ensuring homogenous and stable rtTA expression is essential for the robust and reliable performance of future Tet-On all-in-one designs.
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Affiliation(s)
- Ana G Duran
- Institute of Active Polymers, Helmholtz-Zentrum Hereon, 14513 Teltow, Germany.,Berlin-Brandenburg School for Regenerative Therapies (BSRT), 13353 Berlin, Germany.,Berlin-Brandenburg Center for Regenerative Therapies (BCRT), 13353 Berlin, Germany.,Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin-Brandenburg Center for Regenerative Therapies, Berlin 13353, Germany
| | - Marko Schwestka
- Institute of Active Polymers, Helmholtz-Zentrum Hereon, 14513 Teltow, Germany.,Berlin-Brandenburg Center for Regenerative Therapies (BCRT), 13353 Berlin, Germany
| | - Timo Z Nazari-Shafti
- Department of Cardiothoracic and Vascular Surgery, German Heart Center Berlin, 13353 Berlin, Germany.,Berlin Institute of Health at Charité - Universitätsmedizin Berlin, BIH Center for Regenerative Therapies, 13353 Berlin, Germany.,German Centre for Cardiovascular Research, Partner Site Berlin, 13353 Berlin, Germany
| | - Sebastian Neuber
- Department of Cardiothoracic and Vascular Surgery, German Heart Center Berlin, 13353 Berlin, Germany.,Berlin Institute of Health at Charité - Universitätsmedizin Berlin, BIH Center for Regenerative Therapies, 13353 Berlin, Germany.,German Centre for Cardiovascular Research, Partner Site Berlin, 13353 Berlin, Germany
| | - Christof Stamm
- Institute of Active Polymers, Helmholtz-Zentrum Hereon, 14513 Teltow, Germany.,Department of Cardiothoracic and Vascular Surgery, German Heart Center Berlin, 13353 Berlin, Germany.,German Centre for Cardiovascular Research, Partner Site Berlin, 13353 Berlin, Germany
| | - Manfred Gossen
- Institute of Active Polymers, Helmholtz-Zentrum Hereon, 14513 Teltow, Germany.,Berlin-Brandenburg Center for Regenerative Therapies (BCRT), 13353 Berlin, Germany
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Gödecke N, Herrmann S, Hauser H, Mayer-Bartschmid A, Trautwein M, Wirth D. Rational Design of Single Copy Expression Cassettes in Defined Chromosomal Sites Overcomes Intraclonal Cell-to-Cell Expression Heterogeneity and Ensures Robust Antibody Production. ACS Synth Biol 2021; 10:145-157. [PMID: 33382574 DOI: 10.1021/acssynbio.0c00519] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The expression of endogenous genes as well as transgenes depends on regulatory elements within and surrounding genes as well as their epigenetic modifications. Members of a cloned cell population often show pronounced cell-to-cell heterogeneity with respect to the expression of a certain gene. To investigate the heterogeneity of recombinant protein expression we targeted cassettes into two preselected chromosomal hot-spots in Chinese hamster ovary (CHO) cells. Depending on the gene of interest and the design of the expression cassette, we found strong expression variability that could be reduced by epigenetic modifiers, but not by site-specific recruitment of the modulator dCas9-VPR. In particular, the implementation of ubiquitous chromatin opening elements (UCOEs) reduced cell-to-cell heterogeneity and concomitantly increased expression. The application of this method to recombinant antibody expression confirmed that rational design of cell lines for production of transgenes with predictable and high titers is a promising approach.
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Affiliation(s)
- Natascha Gödecke
- RG Model Systems for Infection and Immunity, Helmholtz Centre for Infection Research, Braunschweig 38124, Germany
| | - Sabrina Herrmann
- RG Model Systems for Infection and Immunity, Helmholtz Centre for Infection Research, Braunschweig 38124, Germany
| | - Hansjörg Hauser
- Staff Unit Scientific Strategy, Helmholtz Centre for Infection Research, Braunschweig 38124, Germany
| | | | | | - Dagmar Wirth
- RG Model Systems for Infection and Immunity, Helmholtz Centre for Infection Research, Braunschweig 38124, Germany
- Institute of Experimental Hematology, Medical University Hannover, Hannover 30625, Germany
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Wahlicht T, Vièyres G, Bruns SA, Meumann N, Büning H, Hauser H, Schmitz I, Pietschmann T, Wirth D. Controlled Functional Zonation of Hepatocytes In Vitro by Engineering of Wnt Signaling. ACS Synth Biol 2020; 9:1638-1649. [PMID: 32551516 DOI: 10.1021/acssynbio.9b00435] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Key liver functions, including protein synthesis, carbohydrate metabolism, and detoxification, are performed by specific populations of hepatocytes that are defined by their relative positions within the liver lobules. On a molecular level, the functional heterogeneity with periportal and pericentral phenotypes, so-called metabolic liver zonation, is mainly established by a gradient of canonical Wnt signaling activity. Since the relevant physiological cues are missing in in vitro liver models, they fail to reflect the functional heterogeneity and thus lack many liver functions. We synthetically re-engineered Wnt signaling in murine and human hepatocytes using a doxycycline-dependent cassette for externally controlled digital expression of stabilized β-catenin. Thereby, we achieved adjustable mosaic-like activation of Wnt signaling in in vitro-cultured hepatocytes that was resistant to negative-feedback loops. This allowed the establishment of long-term-stable periportal-like and pericentral-like phenotypes that mimic the heterogeneity observed in vivo. The in vitro-zonated hepatocytes show differential expression of drug-metabolizing enzymes and associated differential toxicity and higher levels of autophagy. Furthermore, recombinant adeno-associated virus and hepatitis C virus preferentially transduce the pericentral-like zonation phenotype, suggesting a bias of these viruses that has been unappreciated to date. These tightly controlled in vivo-like systems will be important for studies evaluating aspects of liver zonation and for the assessment of drug toxicity for mouse and man.
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Affiliation(s)
- Tom Wahlicht
- Model Systems for Infection and Immunity, Helmholtz Centre for Infection Research, 38124 Braunschweig, Germany
| | - Gabrielle Vièyres
- Institute of Experimental Virology, TWINCORE, Centre for Experimental and Clinical Infection Research, 30625 Hannover, Germany
| | - Svenja A. Bruns
- Systems-Oriented Immunology and Inflammation Research, Helmholtz Centre for Infection Research, 38124 Braunschweig, Germany
- Institute for Molecular and Clinical Immunology, Otto von Guericke University Magdeburg, 39106 Magdeburg, Germany
| | - Nadja Meumann
- German Center for Infection Research (DZIF), Hannover−Braunschweig Partner Site, 38124 Braunschweig, Germany
| | - Hildegard Büning
- German Center for Infection Research (DZIF), Hannover−Braunschweig Partner Site, 38124 Braunschweig, Germany
- REBIRTH Cluster of Excellence, Hannover Medical School, 30625 Hannover, Germany
| | - Hansjörg Hauser
- Department of Scientific Strategy, Helmholtz Centre for Infection Research, 38124 Braunschweig, Germany
| | - Ingo Schmitz
- Systems-Oriented Immunology and Inflammation Research, Helmholtz Centre for Infection Research, 38124 Braunschweig, Germany
- Institute for Molecular and Clinical Immunology, Otto von Guericke University Magdeburg, 39106 Magdeburg, Germany
| | - Thomas Pietschmann
- Institute of Experimental Virology, TWINCORE, Centre for Experimental and Clinical Infection Research, 30625 Hannover, Germany
| | - Dagmar Wirth
- Model Systems for Infection and Immunity, Helmholtz Centre for Infection Research, 38124 Braunschweig, Germany
- Institute of Experimental Hematology, Medical University Hannover, 30625 Hannover, Germany
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Low immunogenic endothelial cells endothelialize the Left Ventricular Assist Device. Sci Rep 2019; 9:11318. [PMID: 31383930 PMCID: PMC6683293 DOI: 10.1038/s41598-019-47780-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2019] [Accepted: 07/03/2019] [Indexed: 12/25/2022] Open
Abstract
Low haemocompatibility of left ventricular assist devices (LVAD) surfaces necessitates anticoagulative therapy. Endothelial cell (EC) seeding can support haemocompatibility, however, the availability of autologous ECs is limited. In contrast, allogeneic ECs are readily available in sufficient quantity, but HLA disparities induce harmful immune responses causing EC loss. In this study, we investigated the feasibility of using allogeneic low immunogenic ECs to endothelialize LVAD sintered inflow cannulas (SIC). To reduce the immunogenicity of ECs, we applied an inducible lentiviral vector to deliver short-hairpins RNA to silence HLA class I expression. HLA class I expression on ECs was conditionally silenced by up to 70%. Sufficient and comparable endothelialization rates were achieved with HLA-expressing or HLA-silenced ECs. Cell proliferation was not impaired by cell-to-Sintered Inflow Cannulas (SIC) contact or by silencing HLA expression. The levels of endothelial phenotypic and thrombogenic markers or cytokine secretion profiles remained unaffected. HLA-silenced ECs-coated SIC exhibited reduced thrombogenicity. In contrast to native ECs, HLA-silenced ECs showed lower cell lysis rates when exposed to allogeneic T cells or specific anti-HLA antibodies. Allogeneic HLA-silenced ECs could potentially become a valuable source for LVAD endothelialization to reduce immunogenicity and correspondingly the need for anticoagulative therapy which can entail severe side effects.
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Gödecke N, Zha L, Spencer S, Behme S, Riemer P, Rehli M, Hauser H, Wirth D. Controlled re-activation of epigenetically silenced Tet promoter-driven transgene expression by targeted demethylation. Nucleic Acids Res 2017; 45:e147. [PMID: 28934472 PMCID: PMC5766184 DOI: 10.1093/nar/gkx601] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2016] [Accepted: 07/03/2017] [Indexed: 12/20/2022] Open
Abstract
Faithful expression of transgenes in cell cultures and mice is often challenged by locus dependent epigenetic silencing. We investigated silencing of Tet-controlled expression cassettes within the mouse ROSA26 locus. We observed pronounced DNA methylation of the Tet promoter concomitant with loss of expression in mES cells as well as in differentiated cells and transgenic animals. Strikingly, the ROSA26 promoter remains active and methylation free indicating that this silencing mechanism specifically affects the transgene, but does not spread to the host's chromosomal neighborhood. To reactivate Tet cassettes a synthetic fusion protein was constructed and expressed in silenced cells. This protein includes the enzymatic domains of ten eleven translocation methylcytosine dioxygenase 1 (TET-1) as well as the Tet repressor DNA binding domain. Expression of the synthetic fusion protein and Doxycycline treatment allowed targeted demethylation of the Tet promoter in the ROSA26 locus and in another genomic site, rescuing transgene expression in cells and transgenic mice. Thus, inducible, reversible and site-specific epigenetic modulation is a promising strategy for reactivation of silenced transgene expression, independent of the integration site.
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Affiliation(s)
- Natascha Gödecke
- Helmholtz Centre for Infection Research, RG Model Systems for Infection and Immunity (MSYS), Braunschweig, Germany
| | - Lisha Zha
- Helmholtz Centre for Infection Research, RG Model Systems for Infection and Immunity (MSYS), Braunschweig, Germany
| | - Shawal Spencer
- Helmholtz Centre for Infection Research, RG Model Systems for Infection and Immunity (MSYS), Braunschweig, Germany
| | - Sara Behme
- Helmholtz Centre for Infection Research, RG Model Systems for Infection and Immunity (MSYS), Braunschweig, Germany
| | - Pamela Riemer
- Helmholtz Centre for Infection Research, RG Model Systems for Infection and Immunity (MSYS), Braunschweig, Germany
| | - Michael Rehli
- University Hospital, Dept. Internal Medicine III, Regensburg, Germany
| | - Hansjörg Hauser
- Helmholtz Centre for Infection Research, Dept. of Scientific Strategy, Braunschweig, Germany
| | - Dagmar Wirth
- Helmholtz Centre for Infection Research, RG Model Systems for Infection and Immunity (MSYS), Braunschweig, Germany.,Hannover Medical School, Experimental Hematology, Hannover, Germany
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Eils R, Ritzerfeld J, Wiechert W. Editorial: Synthetic biology--ready for application. Biotechnol J 2015; 10:229-30. [PMID: 25676050 DOI: 10.1002/biot.201500025] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Roland Eils
- German Cancer Research Center (DKFZ) and University of Heidelberg, Heidelberg, Germany.
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