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Harre J, Heinkele L, Steffens M, Warnecke A, Lenarz T, Just I, Rohrbeck A. Potentiation of Brain-Derived Neurotrophic Factor-Induced Protection of Spiral Ganglion Neurons by C3 Exoenzyme/Rho Inhibitor. Front Cell Neurosci 2021; 15:602897. [PMID: 33776650 PMCID: PMC7991574 DOI: 10.3389/fncel.2021.602897] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2020] [Accepted: 02/19/2021] [Indexed: 11/17/2022] Open
Abstract
Preservation of the excitability of spiral ganglion neurons (SGN) may contribute to an improved speech perception after cochlear implantation. Thus, the application of exogenous neurotrophic factors such as the neurotrophin brain-derived neurotrophic factor (BDNF) to increase SGN survival in vitro and in vivo is a promising pharmacological approach in cochlear implant (CI) research. Due to the difficult pharmacokinetic profile of proteins such as BDNF, there is a quest for small molecules to mediate the survival of SGN or to increase the efficacy of BDNF. The C3 exoenzyme from Clostridium botulinum could be a potential new candidate for the protection and regeneration of SGN. Inhibition of the RhoA GTPase pathway which can be mediated by C3 is described as a promising strategy to enhance axonal regeneration and to exert pro-survival signals in neurons. Nanomolar concentrations of C3, its enzymatically inactive form C3E174Q, and a 26mer C-terminal peptide fragment covering amino acid 156–181 (C3156-181) potentiated the neuroprotective effect on SGN mediated by BDNF in vitro. The neuroprotective effect of C3/BDNF was reduced to the neuroprotective effect of BDNF alone after the treatment with wortmannin, an inhibitor of the phosphatidylinositol-3-kinase (PI3K).The exoenzyme C3 (wild-type and enzyme-deficient) and the C3 peptide fragment C3154–181 present novel biologically active compounds for the protection of the SGN. The exact underlying intracellular mechanisms that mediate the neuroprotective effect are not clarified yet, but the combination of BDNF (TrkB stimulation) and C3 exoenzyme (RhoA inhibition) can be used to protect SGN in vitro.
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Affiliation(s)
- Jennifer Harre
- Department of Otorhinolaryngology, Head and Neck Surgery, Hannover Medical School, Hannover, Germany.,Cluster of Excellence "Hearing4all" of the German Research Foundation (EXC 2177/1), Hannover, Germany
| | - Laura Heinkele
- Department of Otorhinolaryngology, Head and Neck Surgery, Hannover Medical School, Hannover, Germany
| | - Melanie Steffens
- Department of Otorhinolaryngology, Head and Neck Surgery, Hannover Medical School, Hannover, Germany
| | - Athanasia Warnecke
- Department of Otorhinolaryngology, Head and Neck Surgery, Hannover Medical School, Hannover, Germany.,Cluster of Excellence "Hearing4all" of the German Research Foundation (EXC 2177/1), Hannover, Germany
| | - Thomas Lenarz
- Department of Otorhinolaryngology, Head and Neck Surgery, Hannover Medical School, Hannover, Germany.,Cluster of Excellence "Hearing4all" of the German Research Foundation (EXC 2177/1), Hannover, Germany
| | - Ingo Just
- Institute of Toxicology, Hannover Medical School, Hannover, Germany
| | - Astrid Rohrbeck
- Institute of Toxicology, Hannover Medical School, Hannover, Germany
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Tan J, Wang X, Cai S, He F, Zhang D, Li D, Zhu X, Zhou L, Fan N, Liu X. C3 Transferase-Expressing scAAV2 Transduces Ocular Anterior Segment Tissues and Lowers Intraocular Pressure in Mouse and Monkey. MOLECULAR THERAPY-METHODS & CLINICAL DEVELOPMENT 2019; 17:143-155. [PMID: 31909087 PMCID: PMC6938898 DOI: 10.1016/j.omtm.2019.11.017] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/24/2019] [Accepted: 11/19/2019] [Indexed: 01/08/2023]
Abstract
Glaucoma is a lifelong disease with elevated intraocular pressure (IOP) as the main risk factor, and reduction of IOP remains the major treatment for this disease. However, current IOP-lowering therapies are far from being satisfactory. We have demonstrated that the lentivirus-mediated exoenzyme C3 transferase (C3) expression in rat and monkey eyes induced relatively long-term IOP reduction. We now show that intracameral injection of self-complementary AAV2 containing a C3 gene into mouse and monkey eyes resulted in morphological changes in trabecular meshwork and IOP reduction. The vector-transduced corneal endothelium and the C3 transgene expression, not vector itself, induced corneal edema as a result of actin-associated endothelial barrier disruption. There was a positive (quadratic) correlation between measured IOP and grade of corneal edema. This is the first report of using an AAV to transduce the trabecular meshwork of monkeys with a gene capable of altering cellular structure and physiology, indicating a potential gene therapy for glaucoma.
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Affiliation(s)
- Junkai Tan
- Xiamen Eye Center, Xiamen University, Xiamen, China
| | - Xizhen Wang
- Shenzhen Key Laboratory of Ophthalmology, Shenzhen Eye Hospital, Jinan University, Shenzhen, China
| | - Suping Cai
- Shenzhen Key Laboratory of Ophthalmology, Shenzhen Eye Hospital, Jinan University, Shenzhen, China
| | - Fen He
- Shenzhen Key Laboratory of Ophthalmology, Shenzhen Eye Hospital, Jinan University, Shenzhen, China
| | - Daren Zhang
- Xiamen Eye Center, Xiamen University, Xiamen, China
| | - Dongkan Li
- Xiamen Eye Center, Xiamen University, Xiamen, China
| | - Xianjun Zhu
- Institute of Laboratory Medicine, Sichuan Academy of Medical Sciences & Provincial People's Hospital, Chengdu, Sichuan, China.,Institute of Laboratory Animal Sciences, Sichuan Academy of Medical Sciences & Provincial People's Hospital, Chengdu, Sichuan, China
| | - Liang Zhou
- Institute of Laboratory Animal Sciences, Sichuan Academy of Medical Sciences & Provincial People's Hospital, Chengdu, Sichuan, China
| | - Ning Fan
- Shenzhen Key Laboratory of Ophthalmology, Shenzhen Eye Hospital, Jinan University, Shenzhen, China
| | - Xuyang Liu
- Xiamen Eye Center, Xiamen University, Xiamen, China.,Shenzhen Key Laboratory of Ophthalmology, Shenzhen Eye Hospital, Jinan University, Shenzhen, China
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Tan J, Liu G, Zhu X, Wu Z, Wang N, Zhou L, Zhang X, Fan N, Liu X. Lentiviral Vector-Mediated Expression of Exoenzyme C3 Transferase Lowers Intraocular Pressure in Monkeys. Mol Ther 2019; 27:1327-1338. [PMID: 31129118 DOI: 10.1016/j.ymthe.2019.04.021] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2019] [Revised: 04/22/2019] [Accepted: 04/26/2019] [Indexed: 12/17/2022] Open
Abstract
Primary open-angle glaucoma (POAG) is considered a lifelong disease characterized by optic nerve deterioration and visual field damage. Although the disease progression can usually be controlled by lowering the intraocular pressure (IOP), therapeutic effects of current approaches do not last long. Gene therapy could be a promising method for persistent treatment of the disease. Our previous study demonstrated that gene transfer of exoenzyme C3 transferase (C3) to the trabecular meshwork (TM) to inhibit Rho GTPase (Rho), the upstream signal molecule of Rho-associated kinase (ROCK), resulted in lowered IOP in normal rodent eyes. In the present study, we show that the lentiviral vector (LV)-mediated C3 expression inactivates RhoA in human TM cells by ADP ribosylation, resulting in disruption of the actin cytoskeleton and altered cell morphology. In addition, intracameral delivery of the C3 vector to monkey eyes leads to persistently lowered IOP without obvious signs of inflammation. This is the first report of using a vector to transduce the TM of an alive non-human primate with a gene that alters cellular machinery and physiology. Our results in non-human primates support that LV-mediated C3 expression in the TM may have therapeutic potential for glaucoma, the leading cause of irreversible blindness in humans.
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Affiliation(s)
- Junkai Tan
- Xiamen Eye Center, Xiamen University, Xiamen, China; Shenzhen Key Laboratory of Ophthalmology, Shenzhen Eye Hospital, School of Optometry, Shenzhen University, Shenzhen, China
| | - Guo Liu
- Shenzhen Key Laboratory of Ophthalmology, Shenzhen Eye Hospital, School of Optometry, Shenzhen University, Shenzhen, China
| | - Xianjun Zhu
- Institute of Laboratory Animal Sciences, Sichuan Academy of Medical Sciences, Provincial People's Hospital, Chengdu, Sichuan, China; Chengdu Institute of Biology, Sichuan Translational Medicine Research Hospital, Chinese Academy of Sciences, Chengdu, Sichuan, China
| | - Zhijian Wu
- Ocular Gene Therapy Core, National Eye Institute, NIH, 6 Center Drive, Room 307, Bethesda, MD 20892, USA
| | - Ningli Wang
- Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing, China
| | - Liang Zhou
- Institute of Laboratory Animal Sciences, Sichuan Academy of Medical Sciences, Provincial People's Hospital, Chengdu, Sichuan, China
| | - Xiaoguang Zhang
- Shenzhen Key Laboratory of Ophthalmology, Shenzhen Eye Hospital, School of Optometry, Shenzhen University, Shenzhen, China
| | - Ning Fan
- Shenzhen Key Laboratory of Ophthalmology, Shenzhen Eye Hospital, School of Optometry, Shenzhen University, Shenzhen, China
| | - Xuyang Liu
- Xiamen Eye Center, Xiamen University, Xiamen, China; Shenzhen Key Laboratory of Ophthalmology, Shenzhen Eye Hospital, School of Optometry, Shenzhen University, Shenzhen, China.
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Rho-inhibiting C2IN-C3 fusion toxin inhibits chemotactic recruitment of human monocytes ex vivo and in mice in vivo. Arch Toxicol 2017; 92:323-336. [PMID: 28924833 PMCID: PMC5773661 DOI: 10.1007/s00204-017-2058-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2017] [Accepted: 08/31/2017] [Indexed: 10/24/2022]
Abstract
Bacterial protein toxins became valuable molecular tools for the targeted modulation of cell functions in experimental pharmacology and attractive therapeutics because of their potent and specific mode of action in human cells. C2IN-C3lim, a recombinant fusion toxin (~50 kDa) of the Rho-inhibiting C3lim from Clostridium (C.) limosum and a non-toxic portion of the C. botulinum C2 toxin (C2IN), is selectively internalized into the cytosol of monocytic cells where C3lim specifically ADP-ribosylates Rho A and -B, thereby inhibiting Rho-mediated signaling. Thus, we hypothesized that these unique features make C2IN-C3lim an attractive molecule for the targeted pharmacological down-regulation of Rho-mediated functions in monocytes. The analysis of the actin structure and the Rho ADP-ribosylation status implied that C2IN-C3lim entered the cytosol of primary human monocytes from healthy donors ex vivo within 1 h. Moreover, it inhibited the fMLP-induced chemotaxis of human monocytes in a Boyden chamber model ex vivo. Similarly, in a 3-dimensional ex vivo model of extravasation, single cell analysis revealed that C2IN-C3lim-treated cells were not able to move. In a clinically relevant mouse model of blunt chest trauma, the local application of C2IN-C3lim into the lungs after thorax trauma prevented the trauma-induced recruitment of monocytes into the lungs in vivo. Thus, C2IN-C3lim might be an attractive lead compound for novel pharmacological strategies to avoid the cellular damage response caused by monocytes in damaged tissue after trauma and during systemic inflammation. The results suggest that the pathophysiological role of clostridial C3 toxins might be a down-modulation of the innate immune system.
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The Molecular Basis of Toxins' Interactions with Intracellular Signaling via Discrete Portals. Toxins (Basel) 2017; 9:toxins9030107. [PMID: 28300784 PMCID: PMC5371862 DOI: 10.3390/toxins9030107] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2017] [Revised: 03/02/2017] [Accepted: 03/04/2017] [Indexed: 12/20/2022] Open
Abstract
An understanding of the molecular mechanisms by which microbial, plant or animal-secreted toxins exert their action provides the most important element for assessment of human health risks and opens new insights into therapies addressing a plethora of pathologies, ranging from neurological disorders to cancer, using toxinomimetic agents. Recently, molecular and cellular biology dissecting tools have provided a wealth of information on the action of these diverse toxins, yet, an integrated framework to explain their selective toxicity is still lacking. In this review, specific examples of different toxins are emphasized to illustrate the fundamental mechanisms of toxicity at different biochemical, molecular and cellular- levels with particular consideration for the nervous system. The target of primary action has been highlighted and operationally classified into 13 sub-categories. Selected examples of toxins were assigned to each target category, denominated as portal, and the modulation of the different portal’s signaling was featured. The first portal encompasses the plasma membrane lipid domains, which give rise to pores when challenged for example with pardaxin, a fish toxin, or is subject to degradation when enzymes of lipid metabolism such as phospholipases A2 (PLA2) or phospholipase C (PLC) act upon it. Several major portals consist of ion channels, pumps, transporters and ligand gated ionotropic receptors which many toxins act on, disturbing the intracellular ion homeostasis. Another group of portals consists of G-protein-coupled and tyrosine kinase receptors that, upon interaction with discrete toxins, alter second messengers towards pathological levels. Lastly, subcellular organelles such as mitochondria, nucleus, protein- and RNA-synthesis machineries, cytoskeletal networks and exocytic vesicles are also portals targeted and deregulated by other diverse group of toxins. A fundamental concept can be drawn from these seemingly different toxins with respect to the site of action and the secondary messengers and signaling cascades they trigger in the host. While the interaction with the initial portal is largely determined by the chemical nature of the toxin, once inside the cell, several ubiquitous second messengers and protein kinases/ phosphatases pathways are impaired, to attain toxicity. Therefore, toxins represent one of the most promising natural molecules for developing novel therapeutics that selectively target the major cellular portals involved in human physiology and diseases.
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Barth H, Fischer S, Möglich A, Förtsch C. Clostridial C3 Toxins Target Monocytes/Macrophages and Modulate Their Functions. Front Immunol 2015; 6:339. [PMID: 26175735 PMCID: PMC4485225 DOI: 10.3389/fimmu.2015.00339] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2015] [Accepted: 06/17/2015] [Indexed: 12/01/2022] Open
Abstract
The C3 enzymes from Clostridium (C.) botulinum (C3bot) and Clostridium limosum (C3lim) are single chain protein toxins of about 25 kDa that mono-ADP-ribosylate Rho-A, -B, and -C in the cytosol of mammalian cells. We discovered that both C3 proteins are selectively internalized into the cytosol of monocytes and macrophages by an endocytotic mechanism, comparable to bacterial AB-type toxins, while they are not efficiently taken up into the cytosol of other cell types including epithelial cells and fibroblasts. C3-treatment results in disturbed macrophage functions, such as migration and phagocytosis, suggesting a novel function of clostridial C3 toxins as virulence factors, which selectively interfere with these immune cells. Moreover, enzymatic inactive C3 protein serves as a transport system to selectively deliver pharmacologically active molecules into the cytosol of monocytes/macrophages without damaging these cells. This review addresses also the generation of C3-based molecular tools for experimental macrophage pharmacology and cell biology as well as the exploitation of C3 for development of novel therapeutic strategies against monocyte/macrophage-associated diseases.
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Affiliation(s)
- Holger Barth
- Institute of Pharmacology and Toxicology, University of Ulm Medical Center , Ulm , Germany
| | - Stephan Fischer
- Institute of Pharmacology and Toxicology, University of Ulm Medical Center , Ulm , Germany ; Institute of Organic Chemistry III, University of Ulm , Ulm , Germany
| | - Amelie Möglich
- Institute of Pharmacology and Toxicology, University of Ulm Medical Center , Ulm , Germany
| | - Christina Förtsch
- Institute of Pharmacology and Toxicology, University of Ulm Medical Center , Ulm , Germany
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