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Wang L, Li S, Liu Y, Feng DL, Jiang L, Long ZY, Wu YM. Motor neuron degeneration following glycine-mediated excitotoxicity induces spastic paralysis after spinal cord ischemia/reperfusion injury in rabbit. Am J Transl Res 2017; 9:3411-3421. [PMID: 28804557 PMCID: PMC5527255] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2016] [Accepted: 02/13/2017] [Indexed: 06/07/2023]
Abstract
Spinal cord ischemia and reperfusion (SCIR) injury is the major cause of a wide range of complications, including neural degeneration and devastating paraplegia. Decrease of inhibitory neurotransmitters and increase of excitory neurotransmitters are the major cause for the excitotoxicity of neurons. However, no study has reported the temporal loss of motor neuron in the ventral horn of spinal cord area following SCIR-induced spastic paralysis, not even the mechanism under it. In the present study, we found that the rabbits were mainly spastic paralyzed after spinal cord ischemia-reperfusion injury. And the ischemia 60 min group is the optimal treating condition, because of the higher rate of spastic paralysis and lower mortality. Motor neurons in the ventral horn of spinal cord were significant degeneration at 3 h following spastic paralysis and only 12.5% motor neurons were observed at 72 h post-operation, compared with control group. ELISA results indicated that Glycine and GABA were both downregulated following spastic paralysis. But Glycine immediately decreased at 10 min post-operation and lasted for the whole process (at least 72 h). Meanwhile GABA only significantly decreased at 72 h. Furthermore, Glutamic expression was significant upregulation at 3 hours post-operation, and the upregulation back to the base level at 72 h post-operation. Glutamic receptor-(NR1) and Glycine α1 receptor upregulated accordingly, whereas GABBR2 didn't upregulate significantly until at 72 h post-operation. Abundant extracellular Ca2+ influxed into cytoplasm in neurons following spastic paralysis. The type of paraplegia is mainly spastic paraplegia after SCIR (ischemia 60 min treatment). Following spastic paraplegia, motor neuron in the ventral horn of spinal cord area was significant degeneration at early stage and last for the whole process. It may contribute to the decrease of Glycine at early stage and followed exitotoxicity, which caused intracellular calcium overload to make neurons dead. It would lay the foundation for better understanding the motor neuron degeneration and mechanism following spastic paralysis. And it would supply a novel and effective target for spastic paralysis prevention and therapy.
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Affiliation(s)
- Li Wang
- State Key Laboratory of Trauma, Burns and Combined Injury, 3rd Department of Research Institute of Surgery, Daping Hospital, Third Military Medical UniversityChongqing 400042, China
| | - Sen Li
- State Key Laboratory of Trauma, Burns and Combined Injury, 3rd Department of Research Institute of Surgery, Daping Hospital, Third Military Medical UniversityChongqing 400042, China
| | - Yuan Liu
- State Key Laboratory of Trauma, Burns and Combined Injury, 3rd Department of Research Institute of Surgery, Daping Hospital, Third Military Medical UniversityChongqing 400042, China
| | - Dong-Liang Feng
- State Key Laboratory of Trauma, Burns and Combined Injury, 3rd Department of Research Institute of Surgery, Daping Hospital, Third Military Medical UniversityChongqing 400042, China
| | - Long Jiang
- State Key Laboratory of Trauma, Burns and Combined Injury, 3rd Department of Research Institute of Surgery, Daping Hospital, Third Military Medical UniversityChongqing 400042, China
| | - Zai-Yun Long
- State Key Laboratory of Trauma, Burns and Combined Injury, 3rd Department of Research Institute of Surgery, Daping Hospital, Third Military Medical UniversityChongqing 400042, China
| | - Ya-Min Wu
- State Key Laboratory of Trauma, Burns and Combined Injury, 3rd Department of Research Institute of Surgery, Daping Hospital, Third Military Medical UniversityChongqing 400042, China
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Desplantes R, Lévêque C, Muller B, Lotierzo M, Ferracci G, Popoff M, Seagar M, Mamoun R, El Far O. Affinity biosensors using recombinant native membrane proteins displayed on exosomes: application to botulinum neurotoxin B receptor. Sci Rep 2017; 7:1032. [PMID: 28432329 PMCID: PMC5430821 DOI: 10.1038/s41598-017-01198-1] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2017] [Accepted: 03/27/2017] [Indexed: 12/31/2022] Open
Abstract
The development of simple molecular assays with membrane protein receptors in a native conformation still represents a challenging task. Exosomes are extracellular vesicles which, due to their stability and small size, are suited for analysis in various assay formats. Here, we describe a novel approach to sort recombinant fully native and functional membrane proteins to exosomes using a targeting peptide. Specific binding of high affinity ligands to the potassium channel Kv1.2, the G-protein coupled receptor CXCR4, and the botulinum neurotoxin type B (BoNT/B) receptor, indicated their correct assembly and outside out orientation in exosomes. We then developed, using a label-free optical biosensor, a new method to determine the kinetic constants of BoNT/B holotoxin binding to its receptor synaptotagmin2/GT1b ganglioside (kon = 2.3 ×105 M−1.s−1, koff = 1.3 10−4 s−1), yielding an affinity constant (KD = 0.6 nM) similar to values determined from native tissue. In addition, the recombinant binding domain of BoNT/B, a potential vector for neuronal delivery, bound quasi-irreversibly to synaptotagmin 2/GT1b exosomes. Engineered exosomes provide thus a novel means to study membrane proteins for biotechnology and clinical applications.
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Affiliation(s)
- Richard Desplantes
- INSERM, UMR_S 1072, 13015, Marseille, France.,Aix-Marseille Université, 13015, Marseille, France
| | - Christian Lévêque
- INSERM, UMR_S 1072, 13015, Marseille, France.,Aix-Marseille Université, 13015, Marseille, France
| | - Benjamin Muller
- Ciloa, cc90 - Université Montpellier 2, Place E. Bataillon, 34095, Montpellier Cedex 5, France
| | - Manuela Lotierzo
- Ciloa, cc90 - Université Montpellier 2, Place E. Bataillon, 34095, Montpellier Cedex 5, France
| | - Géraldine Ferracci
- Aix-Marseille Université, 13015, Marseille, France.,CNRS, UMR 7286, Plate-Forme de Recherche en Neurosciences PFRN, 13015, Marseille, France
| | - Michel Popoff
- CNR Anaérobies et botulisme, Unité Bactéries anaérobies et toxines. Institut Pasteur, 28 rue du Dr Roux, 75724, Paris, Cedex 15, France
| | - Michael Seagar
- INSERM, UMR_S 1072, 13015, Marseille, France.,Aix-Marseille Université, 13015, Marseille, France
| | - Robert Mamoun
- Ciloa, cc90 - Université Montpellier 2, Place E. Bataillon, 34095, Montpellier Cedex 5, France
| | - Oussama El Far
- INSERM, UMR_S 1072, 13015, Marseille, France. .,Aix-Marseille Université, 13015, Marseille, France.
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Masuyer G, Chaddock JA, Foster KA, Acharya KR. Engineered botulinum neurotoxins as new therapeutics. Annu Rev Pharmacol Toxicol 2013; 54:27-51. [PMID: 24016211 DOI: 10.1146/annurev-pharmtox-011613-135935] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Botulinum neurotoxins (BoNTs) cause flaccid paralysis by inhibiting neurotransmission at cholinergic nerve terminals. Each BoNT consists of three domains that are essential for toxicity: the binding domain, the translocation domain, and the catalytic light-chain domain. BoNT modular architecture is associated with a multistep mechanism that culminates in the intracellular proteolysis of SNARE (soluble N-ethylmaleimide-sensitive-fusion-protein attachment protein receptor) proteins, which prevents synaptic vesicle exocytosis. As the most toxic proteins known, BoNTs have been extensively studied and are used as pharmaceutical agents to treat an increasing variety of disorders. This review summarizes the level of sophistication reached in BoNT engineering and highlights the diversity of approaches taken to utilize the modularity of the toxin. Improved efficiency and applicability have been achieved by direct mutagenesis and interserotype domain rearrangement. The scope of BoNT activity has been extended to nonneuronal cells and offers the basis for novel biomolecules in the treatment of secretion disorders.
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Affiliation(s)
- Geoffrey Masuyer
- Department of Biology and Biochemistry, University of Bath, Claverton Down, Bath BA2 7AY, United Kingdom;
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