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Mukhamedyarov MA, Khabibrakhmanov AN, Khuzakhmetova VF, Giniatullin AR, Zakirjanova GF, Zhilyakov NV, Mukhutdinova KA, Samigullin DV, Grigoryev PN, Zakharov AV, Zefirov AL, Petrov AM. Early Alterations in Structural and Functional Properties in the Neuromuscular Junctions of Mutant FUS Mice. Int J Mol Sci 2023; 24:9022. [PMID: 37240370 PMCID: PMC10218837 DOI: 10.3390/ijms24109022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2023] [Revised: 05/16/2023] [Accepted: 05/18/2023] [Indexed: 05/28/2023] Open
Abstract
Amyotrophic lateral sclerosis (ALS) is manifested as skeletal muscle denervation, loss of motor neurons and finally severe respiratory failure. Mutations of RNA-binding protein FUS are one of the common genetic reasons of ALS accompanied by a 'dying back' type of degeneration. Using fluorescent approaches and microelectrode recordings, the early structural and functional alterations in diaphragm neuromuscular junctions (NMJs) were studied in mutant FUS mice at the pre-onset stage. Lipid peroxidation and decreased staining with a lipid raft marker were found in the mutant mice. Despite the preservation of the end-plate structure, immunolabeling revealed an increase in levels of presynaptic proteins, SNAP-25 and synapsin 1. The latter can restrain Ca2+-dependent synaptic vesicle mobilization. Indeed, neurotransmitter release upon intense nerve stimulation and its recovery after tetanus and compensatory synaptic vesicle endocytosis were markedly depressed in FUS mice. There was a trend to attenuation of axonal [Ca2+]in increase upon nerve stimulation at 20 Hz. However, no changes in neurotransmitter release and the intraterminal Ca2+ transient in response to low frequency stimulation or in quantal content and the synchrony of neurotransmitter release at low levels of external Ca2+ were detected. At a later stage, shrinking and fragmentation of end plates together with a decrease in presynaptic protein expression and disturbance of the neurotransmitter release timing occurred. Overall, suppression of synaptic vesicle exo-endocytosis upon intense activity probably due to alterations in membrane properties, synapsin 1 levels and Ca2+ kinetics could be an early sign of nascent NMJ pathology, which leads to neuromuscular contact disorganization.
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Affiliation(s)
- Marat A. Mukhamedyarov
- Department of Normal Physiology, Kazan State Medial University, 49 Butlerova St., Kazan 420012, Russia; (M.A.M.)
| | - Aydar N. Khabibrakhmanov
- Department of Normal Physiology, Kazan State Medial University, 49 Butlerova St., Kazan 420012, Russia; (M.A.M.)
| | - Venera F. Khuzakhmetova
- Kazan Institute of Biochemistry and Biophysics, Federal Research Center ‘‘Kazan Scientific Center of RAS”, 2/31 Lobachevsky St., P.O. Box 30, Kazan 420111, Russia (N.V.Z.)
| | - Arthur R. Giniatullin
- Department of Normal Physiology, Kazan State Medial University, 49 Butlerova St., Kazan 420012, Russia; (M.A.M.)
- Kazan Institute of Biochemistry and Biophysics, Federal Research Center ‘‘Kazan Scientific Center of RAS”, 2/31 Lobachevsky St., P.O. Box 30, Kazan 420111, Russia (N.V.Z.)
| | - Guzalia F. Zakirjanova
- Department of Normal Physiology, Kazan State Medial University, 49 Butlerova St., Kazan 420012, Russia; (M.A.M.)
- Kazan Institute of Biochemistry and Biophysics, Federal Research Center ‘‘Kazan Scientific Center of RAS”, 2/31 Lobachevsky St., P.O. Box 30, Kazan 420111, Russia (N.V.Z.)
| | - Nikita V. Zhilyakov
- Kazan Institute of Biochemistry and Biophysics, Federal Research Center ‘‘Kazan Scientific Center of RAS”, 2/31 Lobachevsky St., P.O. Box 30, Kazan 420111, Russia (N.V.Z.)
| | - Kamilla A. Mukhutdinova
- Department of Normal Physiology, Kazan State Medial University, 49 Butlerova St., Kazan 420012, Russia; (M.A.M.)
| | - Dmitry V. Samigullin
- Kazan Institute of Biochemistry and Biophysics, Federal Research Center ‘‘Kazan Scientific Center of RAS”, 2/31 Lobachevsky St., P.O. Box 30, Kazan 420111, Russia (N.V.Z.)
- Department of Radiophotonics and Microwave Technologies, Kazan National Research Technical University, 10 K. Marx St., Kazan 420111, Russia
| | - Pavel N. Grigoryev
- Department of Normal Physiology, Kazan State Medial University, 49 Butlerova St., Kazan 420012, Russia; (M.A.M.)
| | - Andrey V. Zakharov
- Department of Normal Physiology, Kazan State Medial University, 49 Butlerova St., Kazan 420012, Russia; (M.A.M.)
- Laboratory of Neurobiology, Kazan Federal University, Kazan 420008, Russia
| | - Andrey L. Zefirov
- Department of Normal Physiology, Kazan State Medial University, 49 Butlerova St., Kazan 420012, Russia; (M.A.M.)
| | - Alexey M. Petrov
- Department of Normal Physiology, Kazan State Medial University, 49 Butlerova St., Kazan 420012, Russia; (M.A.M.)
- Kazan Institute of Biochemistry and Biophysics, Federal Research Center ‘‘Kazan Scientific Center of RAS”, 2/31 Lobachevsky St., P.O. Box 30, Kazan 420111, Russia (N.V.Z.)
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Grigoryev PN, Zefirov AL. Myosin accelerates synaptic vesicle recycling in the motor nerve endings. Dokl Biol Sci 2016; 470:217-219. [PMID: 27822755 DOI: 10.1134/s0012496616050112] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/24/2016] [Indexed: 11/23/2022]
Abstract
Neurotransmitter release and exocytosis of synaptic vesicles in the motor nerve endings of the frog cutaneous-pectoris muscle were studied using electrophysiological and optical methods under the conditions of inhibition of the myosin light-chain kinase and non-muscle myosin by the specific inhibitors ML-7 (12 μM) and (-)-blebbistatin (100 μM). At high-frequency stimulation (20 pulses/s), these inhibitors strengthened suppression of transmitter release during the first 20-25 s and slowed down the release of the fluorescent dye FM 1-43. The obtained results indicate that myosin accelerates rapid synaptic vesicle recycling upon high-frequency stimulation.
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Affiliation(s)
- P N Grigoryev
- Kazan State Medical University, Ministry of Health, Kazan, Tatarstan, Russia
| | - A L Zefirov
- Kazan State Medical University, Ministry of Health, Kazan, Tatarstan, Russia.
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Zefirov AL, Abdrakhmanov MM, Mukhamedyarov MA, Grigoryev PN. The role of extracellular calcium in exo- and endocytosis of synaptic vesicles at the frog motor nerve terminals. Neuroscience 2006; 143:905-10. [PMID: 17000054 DOI: 10.1016/j.neuroscience.2006.08.025] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2006] [Revised: 08/16/2006] [Accepted: 08/16/2006] [Indexed: 11/26/2022]
Abstract
In the present study we combined FM 1-43 imaging and electrophysiological recording of miniature end-plate currents (MEPCs) to determine the role of extracellular calcium in synaptic vesicle exo- and endocytosis at the frog motor nerve terminals. We replaced extracellular Ca2+ ions with other bivalent cations (Sr2+, Ba2+, Cd2+, Mg2+) or used a calcium-free solution and monitored fluorescent staining of the nerve terminals in the presence of caffeine, which promotes the release of Ca2+ from intracellular stores. Caffeine has induced FM1-43 internalization only in the presence of bivalent cations in the external solution. The exposure of the neuromuscular junction to caffeine in a calcium-free solution caused a reversible failure of FM 1-43 loading and an increase in the nerve terminal width. This effect of a calcium-free solution was not due to a decrease in exocytosis, because caffeine-induced FM1-43 unloading from the previously loaded nerve terminals, as well as a degree of the MEPCs frequency increase, was unchanged. We conclude that the presence of Ca2+ or other bivalent cations in extracellular space is necessary for endocytosis but not for exocytosis of synaptic vesicles, while transmitter release is promoted by efflux of Ca2+ from intracellular stores. The effect of extracellular Ca2+ on endocytosis might be driven by the non-specific interactions with membrane lipids.
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Affiliation(s)
- A L Zefirov
- Department of Physiology, Kazan State Medical University, Butlerov Street 49, Kazan, Russia 420012
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