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Liu Y, Charpin-El Hamri G, Ye H, Fussenegger M. A synthetic free fatty acid-regulated transgene switch in mammalian cells and mice. Nucleic Acids Res 2019; 46:9864-9874. [PMID: 30219861 PMCID: PMC6182168 DOI: 10.1093/nar/gky805] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2018] [Accepted: 08/28/2018] [Indexed: 02/06/2023] Open
Abstract
Trigger-inducible transgene expression systems are utilized in biopharmaceutical manufacturing and also to enable controlled release of therapeutic agents in vivo. We considered that free fatty acids (FFAs), which are dietary components, signaling molecules and important biomarkers, would be attractive candidates as triggers for novel transgene switches with many potential applications, e.g. in future gene- and cell-based therapies. To develop such a switch, we rewired the signal pathway of human G-protein coupled receptor 40 to a chimeric promoter triggering gene expression through an increase of intracellular calcium concentration. This synthetic gene switch is responsive to physiologically relevant FFA concentrations in different mammalian cell types grown in culture or in a bioreactor, or implanted into mice. Animal recipients of microencapsulated sensor cells containing this switch exhibited significant transgene induction following consumption of dietary fat (such as Swiss cheese) or under hyperlipidaemic conditions, including obesity, diabetes and lipodystrophy.
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Affiliation(s)
- Ying Liu
- Department of Biosystems Science and Engineering, ETH Zurich, Mattenstrasse 26, CH-4058 Basel, Switzerland
| | - Ghislaine Charpin-El Hamri
- Département Génie Biologique, Université Claude Bernard 1, 43 Boulevard du 11 Novembre 1918, F-69100 Villeurbanne, France
| | - Haifeng Ye
- Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences and School of Life Sciences, East China Normal University, Dongchuan Road 500, Shanghai 200241, China
| | - Martin Fussenegger
- Department of Biosystems Science and Engineering, ETH Zurich, Mattenstrasse 26, CH-4058 Basel, Switzerland.,Faculty of Science, University of Basel, Mattenstrasse 26, CH-4058 Basel, Switzerland
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Abstract
OBJECTIVE Effective management of patients diagnosed with ototoxicity is needed to reduce hearing and balance damage which affects communication and life quality. Despite widespread recommendations to monitor and manage ototoxicity in an early and effective manner, there is limited evidence to support the actual implementation of these recommendations for affected patient groups in healthcare services across the UK with limited publications available. In this study, an online questionnaire analysed the current practice of ototoxicity management and patient pathways across the UK once the diagnosis of ototoxicity was confirmed, targeting Audiologists, ENTs/AVPs and GPs. DESIGN Qualitative Survey Study. STUDY SAMPLE A randomised sample of hearing services in the UK, including audiology departments; GP practices and local health settings were targeted with a total of 134 completed surveys. RESULTS About 72% reported the absence of ototoxicity management protocols within their centre. Results depicted great inconsistency and variation across the UK in ototoxicity management services provided, treatment modification, monitoring and referral pathways. CONCLUSION Developing and advocating national guidelines are intended not only to inform clinical decision making but to provide minimum standards of care in ototoxicity management and offer greater awareness and education to improve patients' quality of life.
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Affiliation(s)
- Devina Maru
- a UCL Ear Institute , University College London , London , UK
| | - Ghada-Al Malky
- a UCL Ear Institute , University College London , London , UK
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Glutz A, Leitmeyer K, Setz C, Brand Y, Bodmer D. Metformin Protects Auditory Hair Cells from Gentamicin-Induced Toxicity in vitro. Audiol Neurootol 2015; 20:360-9. [PMID: 26372952 DOI: 10.1159/000438918] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2014] [Accepted: 07/23/2015] [Indexed: 11/19/2022] Open
Abstract
Metformin is a commonly used antidiabetic drug. It has been shown that this drug activates the AMP-activated protein kinase, which inhibits downstream the mammalian target of rapamycin. In addition, several studies indicate that metformin reduces intracellular reactive oxygen species. Our data, using an in vitro rat model, indicate that metformin is able to protect auditory hair cells (HCs) from gentamicin-induced apoptotic cell death. Moreover, metformin has no toxic effect on spiral ganglion neuronal survival or outgrowth in vitro. These results suggest a protective effect of metformin on auditory HC survival in gentamicin-induced HC loss in vitro.
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Affiliation(s)
- Andrea Glutz
- Department of Biomedicine, Head and Neck Surgery, University Hospital Basel, Basel, Switzerland
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Inhibition of mTOR by Rapamycin Results in Auditory Hair Cell Damage and Decreased Spiral Ganglion Neuron Outgrowth and Neurite Formation In Vitro. BIOMED RESEARCH INTERNATIONAL 2015; 2015:925890. [PMID: 25918725 PMCID: PMC4395993 DOI: 10.1155/2015/925890] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/22/2014] [Revised: 03/10/2015] [Accepted: 03/11/2015] [Indexed: 12/21/2022]
Abstract
Rapamycin is an antifungal agent with immunosuppressive properties. Rapamycin inhibits the mammalian target of rapamycin (mTOR) by blocking the mTOR complex 1 (mTORC1). mTOR is an atypical serine/threonine protein kinase, which controls cell growth, cell proliferation, and cell metabolism. However, less is known about the mTOR pathway in the inner ear. First, we evaluated whether or not the two mTOR complexes (mTORC1 and mTORC2, resp.) are present in the mammalian cochlea. Next, tissue explants of 5-day-old rats were treated with increasing concentrations of rapamycin to explore the effects of rapamycin on auditory hair cells and spiral ganglion neurons. Auditory hair cell survival, spiral ganglion neuron number, length of neurites, and neuronal survival were analyzed in vitro. Our data indicates that both mTOR complexes are expressed in the mammalian cochlea. We observed that inhibition of mTOR by rapamycin results in a dose dependent damage of auditory hair cells. Moreover, spiral ganglion neurite number and length of neurites were significantly decreased in all concentrations used compared to control in a dose dependent manner. Our data indicate that the mTOR may play a role in the survival of hair cells and modulates spiral ganglion neuronal outgrowth and neurite formation.
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Role of somatostatin receptor-2 in gentamicin-induced auditory hair cell loss in the Mammalian inner ear. PLoS One 2014; 9:e108146. [PMID: 25268135 PMCID: PMC4182454 DOI: 10.1371/journal.pone.0108146] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2014] [Accepted: 08/18/2014] [Indexed: 01/10/2023] Open
Abstract
Hair cells and spiral ganglion neurons of the mammalian auditory system do not regenerate, and their loss leads to irreversible hearing loss. Aminoglycosides induce auditory hair cell death in vitro, and evidence suggests that phosphatidylinositol-3-kinase/Akt signaling opposes gentamicin toxicity via its downstream target, the protein kinase Akt. We previously demonstrated that somatostatin-a peptide with hormone/neurotransmitter properties-can protect hair cells from gentamicin-induced hair cell death in vitro, and that somatostatin receptors are expressed in the mammalian inner ear. However, it remains unknown how this protective effect is mediated. In the present study, we show a highly significant protective effect of octreotide (a drug that mimics and is more potent than somatostatin) on gentamicin-induced hair cell death, and increased Akt phosphorylation in octreotide-treated organ of Corti explants in vitro. Moreover, we demonstrate that somatostatin receptor-1 knockout mice overexpress somatostatin receptor-2 in the organ of Corti, and are less susceptible to gentamicin-induced hair cell loss than wild-type or somatostatin-1/somatostatin-2 double-knockout mice. Finally, we show that octreotide affects auditory hair cells, enhances spiral ganglion neurite number, and decreases spiral ganglion neurite length.
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Janeschik S, Teschendorf M, Bagus H, Arweiler-Harbeck D. Influence of etiologic factors on speech perception of cochlear-implanted children. Cochlear Implants Int 2013; 14:190-9. [DOI: 10.1179/1754762812y.0000000017] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
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Brand Y, Setz C, Levano S, Listyo A, Chavez E, Pak K, Sung M, Radojevic V, Ryan AF, Bodmer D. Simvastatin protects auditory hair cells from gentamicin-induced toxicity and activates Akt signaling in vitro. BMC Neurosci 2011; 12:114. [PMID: 22082490 PMCID: PMC3250952 DOI: 10.1186/1471-2202-12-114] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2011] [Accepted: 11/14/2011] [Indexed: 01/11/2023] Open
Abstract
Background Inhibitors of 3-hydroxy-3-methylglutaryl-coenzyme A reductase, known as statins, are commonly used as cholesterol-lowering drugs. During the past decade, evidence has emerged that statins also have neuroprotective effects. Research in the retina has shown that simvastatin, a commonly used statin, increases Akt phosphorylation in vivo, indicating that the PI3K/Akt pathway contributes to the protective effects achieved. While research about neuroprotective effects have been conducted in several systems, the effects of statins on the inner ear are largely unknown. Results We evaluated whether the 3-hydroxy-3-methylglutaryl-coenzyme A reductase is present within the rat cochlea and whether simvastatin is able to protect auditory hair cells from gentamicin-induced apoptotic cell death in a in vitro mouse model. Furthermore, we evaluated whether simvastatin increases Akt phosphorylation in the organ of Corti. We detected 3-hydroxy-3-methylglutaryl-coenzyme A reductase mRNA in organ of Corti, spiral ganglion, and stria vascularis by reverse transcriptase-polymerase chain reaction (RT-PCR). Moreover, we observed a dose-dependent and significant reduction of hair cell loss in organs of Corti treated with simvastatin in addition to gentamicin, as compared to samples treated with gentamicin alone. The protective effect of simvastatin was reversed by addition of mevalonate, a downstream metabolite blocked by simvastatin, demonstrating the specificity of protection. Finally, Western blotting showed an increase in organ of Corti Akt phosphorylation after simvastatin treatment in vitro. Conclusion These results suggest a neuroprotective effect of statins in the inner ear, mediated by reduced 3-hydroxy-3-methylglutaryl-coenzyme A reductase metabolism and Akt activation.
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Affiliation(s)
- Yves Brand
- Department of Biomedicine, University Hospital Basel, Hebelstrasse 20, 4031 Basel, Switzerland
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Volkenstein S, Kirkwood JE, Lai E, Dazert S, Fuller GG, Heller S. Oriented collagen as a potential cochlear implant electrode surface coating to achieve directed neurite outgrowth. Eur Arch Otorhinolaryngol 2011; 269:1111-6. [PMID: 21952794 DOI: 10.1007/s00405-011-1775-8] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2010] [Accepted: 09/13/2011] [Indexed: 12/27/2022]
Abstract
In patients with severe to profound hearing loss, cochlear implants (CIs) are currently the only therapeutic option when the amplification with conventional hearing aids does no longer lead to a useful hearing experience. Despite its great success, there are patients in which benefit from these devices is rather limited. One reason may be a poor neuron-device interaction, where the electric fields generated by the electrode array excite a wide range of tonotopically organized spiral ganglion neurons at the cost of spatial resolution. Coating of CI electrodes to provide a welcoming environment combined with suitable surface chemistry (e.g. with neurotrophic factors) has been suggested to create a closer bioelectrical interface between the electrode array and the target tissue, which might lead to better spatial resolution, better frequency discrimination, and ultimately may improve speech perception in patients. Here we investigate the use of a collagen surface with a cholesteric banding structure, whose orientation can be systemically controlled as a guiding structure for neurite outgrowth. We demonstrate that spiral ganglion neurons survive on collagen-coated surfaces and display a directed neurite growth influenced by the direction of collagen fibril deposition. The majority of neurites grow parallel to the orientation direction of the collagen. We suggest collagen coating as a possible future option in CI technology to direct neurite outgrowth and improve hearing results for affected patients.
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Affiliation(s)
- Stefan Volkenstein
- Department of Otolaryngology, Head and Neck Surgery, Stanford University School of Medicine, Stanford, CA 94305, USA.
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Volkenstein S, Brors D, Hansen S, Minovi A, Laub M, Jennissen HP, Dazert S, Neumann A. Influence of bone morphogenetic protein-2 on spiral ganglion neurite growth in vitro. Eur Arch Otorhinolaryngol 2009; 266:1381-9. [DOI: 10.1007/s00405-009-0930-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2008] [Accepted: 02/17/2009] [Indexed: 11/28/2022]
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Hartenbach S, Daoud-El Baba M, Weber W, Fussenegger M. An engineered L-arginine sensor of Chlamydia pneumoniae enables arginine-adjustable transcription control in mammalian cells and mice. Nucleic Acids Res 2007; 35:e136. [PMID: 17947334 PMCID: PMC2175317 DOI: 10.1093/nar/gkm652] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
For optimal compatibility with biopharmaceutical manufacturing and gene therapy, heterologous transgene control systems must be responsive to side-effect-free physiologic inducer molecules. The arginine-inducible interaction of the ArgR repressor and the ArgR-specific ARG box, which synchronize arginine import and synthesis in the intracellular human pathogen Chlamydia pneumoniae, was engineered for arginine-regulated transgene (ART) expression in mammalian cells. A synthetic arginine-responsive transactivator (ARG), consisting of ArgR fused to the Herpes simplex VP16 transactivation domain, reversibly adjusted transgene transcription of chimeric ARG box-containing mammalian minimal promoters (PART) in an arginine-inducible manner. Arginine-controlled transgene expression showed rapid induction kinetics in a variety of mammalian cell lines and was adjustable and reversible at concentrations which were compatible with host cell physiology. ART variants containing different transactivation domains, variable spacing between ARG box and minimal promoter and several tandem ARG boxes showed modified regulation performance tailored for specific expression scenarios and cell types. Mice implanted with microencapsulated cells engineered for ART-inducible expression of the human placental secreted alkaline phosphatase (SEAP) exhibited adjustable serum phosphatase levels after treatment with different arginine doses. Using a physiologic inducer, such as the amino acid l-arginine, to control heterologous transgenes in a seamless manner which is devoid of noticeable metabolic interference will foster novel opportunities for precise expression dosing in future gene therapy scenarios as well as the manufacturing of difficult-to-produce protein pharmaceuticals.
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Affiliation(s)
- Shizuka Hartenbach
- Institute for Chemical and Bioengineering, ETH Zurich, Wolfgang-Pauli-Strasse 10, HCI F115, CH-8093 Zurich, Switzerland
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Malphettes L, Weber CC, El-Baba MD, Schoenmakers RG, Aubel D, Weber W, Fussenegger M. A novel mammalian expression system derived from components coordinating nicotine degradation in arthrobacter nicotinovorans pAO1. Nucleic Acids Res 2005; 33:e107. [PMID: 16002786 PMCID: PMC1174900 DOI: 10.1093/nar/gni107] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
We describe the design and detailed characterization of 6-hydroxy-nicotine (6HNic)-adjustable transgene expression (NICE) systems engineered for lentiviral transduction and in vivo modulation of angiogenic responses. Arthrobacter nicotinovorans pAO1 encodes a unique catabolic machinery on its plasmid pAO1, which enables this Gram-positive soil bacterium to use the tobacco alkaloid nicotine as the exclusive carbon source. The 6HNic-responsive repressor-operator (HdnoR-O(NIC)) interaction, controlling 6HNic oxidase production in A.nicotinovorans pAO1, was engineered for generic 6HNic-adjustable transgene expression in mammalian cells. HdnoR fused to different transactivation domains retained its O(NIC)-binding capacity in mammalian cells and reversibly adjusted transgene transcription from chimeric O(NIC)-containing promoters (P(NIC); O(NIC) fused to a minimal eukaryotic promoter [P(min)]) in a 6HNic-responsive manner. The combination of transactivators containing various transactivation domains with promoters differing in the number of operator modules as well as in their relative inter-O(NIC) and/or O(NIC)-P(min) spacing revealed steric constraints influencing overall NICE regulation performance in mammalian cells. Mice implanted with microencapsulated cells engineered for NICE-controlled expression of the human glycoprotein secreted placental alkaline phosphatase (SEAP) showed high SEAP serum levels in the absence of regulating 6HNic. 6HNic was unable to modulate SEAP expression, suggesting that this nicotine derivative exhibits control-incompatible pharmacokinetics in mice. However, chicken embryos transduced with HIV-1-derived self-inactivating lentiviral particles transgenic for NICE-adjustable expression of the human vascular endothelial growth factor 121 (VEGF121) showed graded 6HNic response following administration of different 6HNic concentrations. Owing to the clinically inert and highly water-soluble compound 6HNic, NICE-adjustable transgene control systems may become a welcome alternative to available drug-responsive homologs in basic research, therapeutic cell engineering and biopharmaceutical manufacturing.
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Affiliation(s)
- Laetitia Malphettes
- Institute for Chemical and Bio-Engineering (ICB), Swiss Federal Institute of Technology, ETH Hoenggerberg, HCI F115Wolfgang-Pauli-Strasse 10, CH-8093 Zurich, Switzerland
| | | | - Marie Daoud El-Baba
- Département Génie Biologique, Institut Universitaire de Technologie, IUTA43 Boulevard du 11 Novembre 1918, F-69622 Villeurbanne Cedex, France
| | - Ronald G. Schoenmakers
- Institute for Chemical and Bio-Engineering (ICB), Swiss Federal Institute of Technology, ETH Hoenggerberg, HCI F115Wolfgang-Pauli-Strasse 10, CH-8093 Zurich, Switzerland
- Integrative Bioscience Institute, Swiss Federal Institute of Technology LausanneCH-1015 Lausanne, Switzerland
| | - Dominique Aubel
- Département Génie Biologique, Institut Universitaire de Technologie, IUTA43 Boulevard du 11 Novembre 1918, F-69622 Villeurbanne Cedex, France
| | - Wilfried Weber
- Institute for Chemical and Bio-Engineering (ICB), Swiss Federal Institute of Technology, ETH Hoenggerberg, HCI F115Wolfgang-Pauli-Strasse 10, CH-8093 Zurich, Switzerland
| | - Martin Fussenegger
- Institute for Chemical and Bio-Engineering (ICB), Swiss Federal Institute of Technology, ETH Hoenggerberg, HCI F115Wolfgang-Pauli-Strasse 10, CH-8093 Zurich, Switzerland
- To whom correspondence should be addressed. Tel: +41 44 633 3448; Fax: +41 44 633 1234;
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