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Gafurova CR, Tsentsevitsky AN, Fedorov NS, Khaziev AN, Malomouzh AI, Petrov AM. β2-Adrenergic Regulation of the Neuromuscular Transmission and Its Lipid-Dependent Switch. Mol Neurobiol 2024; 61:6805-6821. [PMID: 38353924 DOI: 10.1007/s12035-024-03991-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2023] [Accepted: 01/26/2024] [Indexed: 08/22/2024]
Abstract
β2-Adrenoceptors (β2-ARs) are the most abundant subtype of adrenergic receptors in skeletal muscles. Their activation via a stabilization of postsynaptic architecture has beneficial effects in certain models of neuromuscular disorders. However, the ability of β2-ARs to regulate neuromuscular transmission at the presynaptic level is poorly understood. Using electrophysiological recordings and fluorescent FM dyes, we found that β2-AR activation with fenoterol enhanced an involvement of synaptic vesicles in exocytosis and neurotransmitter release during intense activity at the neuromuscular junctions of mouse diaphragm. This was accompanied by an improvement of contractile responses to phrenic nerve stimulation (but not direct stimulation of the muscle fibers) at moderate-to-high frequencies. β2-ARs mainly reside in lipid microdomains enriched with cholesterol and sphingomyelin. The latter is hydrolyzed by sphingomyelinases, whose upregulation occurs in many conditions characterized by muscle atrophy and sympathetic nerve hyperactivity. Sphingomyelinase treatment reversed the effects of β2-AR agonist on the neurotransmitter release and synaptic vesicle recruitment to the exocytosis during intense activity. Inhibition of Gi protein with pertussis toxin completely prevented the sphingomyelinase-mediated inversion in the β2-AR agonist action. Note that lipid raft disrupting enzyme cholesterol oxidase had the same effect on β2-AR agonist-mediated changes in neurotransmission as sphingomyelinase. Thus, β2-AR agonist fenoterol augmented recruitment and release of synaptic vesicles during intense activity in the diaphragm neuromuscular junctions. Sphingomyelin hydrolysis inversed the effects of β2-AR agonist on neurotransmission probably via switching to Gi protein-dependent signaling. This phenomenon may reflect a dependence of the β2-AR signaling on lipid raft integrity in the neuromuscular junctions.
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Affiliation(s)
- Chulpan R Gafurova
- Laboratory of Biophysics of Synaptic Processes, Kazan Institute of Biochemistry and Biophysics, FRC Kazan Scientific Center of RAS, 2/31 Lobachevsky St., Kazan, RT, Russia, 420111
- Kazan State Medical University, 49 Butlerova St., Kazan, RT, Russia, 420012
| | - Andrei N Tsentsevitsky
- Laboratory of Biophysics of Synaptic Processes, Kazan Institute of Biochemistry and Biophysics, FRC Kazan Scientific Center of RAS, 2/31 Lobachevsky St., Kazan, RT, Russia, 420111
| | - Nikita S Fedorov
- Laboratory of Biophysics of Synaptic Processes, Kazan Institute of Biochemistry and Biophysics, FRC Kazan Scientific Center of RAS, 2/31 Lobachevsky St., Kazan, RT, Russia, 420111
| | - Arthur N Khaziev
- Laboratory of Biophysics of Synaptic Processes, Kazan Institute of Biochemistry and Biophysics, FRC Kazan Scientific Center of RAS, 2/31 Lobachevsky St., Kazan, RT, Russia, 420111
| | - Artem I Malomouzh
- Laboratory of Biophysics of Synaptic Processes, Kazan Institute of Biochemistry and Biophysics, FRC Kazan Scientific Center of RAS, 2/31 Lobachevsky St., Kazan, RT, Russia, 420111
- Kazan National Research Technical University, 10, K. Marx St., Kazan, Russia, 420111
| | - Alexey M Petrov
- Laboratory of Biophysics of Synaptic Processes, Kazan Institute of Biochemistry and Biophysics, FRC Kazan Scientific Center of RAS, 2/31 Lobachevsky St., Kazan, RT, Russia, 420111.
- Kazan State Medical University, 49 Butlerova St., Kazan, RT, Russia, 420012.
- Kazan Federal University, 18 Kremlyovskaya St., Kazan, Russia, 420008.
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Minibayeva FV, Rassabina AE, Zakirjanova GF, Fedorov NS, Khabibrakhmanova VR, Galeeva EI, Kuznetsova EA, Malomouzh AI, Petrov AM. Protective properties of melanin from lichen Lobaria pulmonaria (L.) HOFFM. In models of oxidative stress in skeletal muscle. Fitoterapia 2024; 177:106127. [PMID: 39019238 DOI: 10.1016/j.fitote.2024.106127] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2024] [Revised: 06/16/2024] [Accepted: 07/13/2024] [Indexed: 07/19/2024]
Abstract
Melanin is a dark pigment from the group of phenolic or indole polymers with inherent biocompatibility and antioxidant capacity. In extremophilic lichen Lobaria pulmonaria, melanin is responsible for protective properties against hostile environments. Herein, the ability of melanin extracted from L. pulmonaria to counteract oxidative stress and related damages was studied in the mouse diaphragm, the main respiratory muscle. Initial in vitro experiments demonstrated ultraviolet (UV)-absorbing, antioxidant and metal chelating activities of melanin. This melanin can form nanoparticles and stabile colloidal system at concentration of 5 μg/ml. Pretreatment of the muscle with melanin (5 μg/ml) markedly reduced UV-induced increase in intracellular and extracellular reactive oxygen species (ROS) as well as antimycin A-mediated enhancement in mitochondrial ROS production accompanied by lipid peroxidation and membrane asymmetry loss. In addition, melanin attenuated suppression of neuromuscular transmission and alterations of contractile responses provoked by hydrogen peroxide. Thus, this study shed the light on the perspectives of the application of a lichen melanin as a protective component for treatment of skeletal muscle disorders, which are accompanied with an increased ROS production.
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Affiliation(s)
- Farida V Minibayeva
- Kazan Institute of Biochemistry and Biophysics, Federal Research Center "Kazan Scientific Center of RAS", 2/31 Lobachevsky Street, Box 30, Kazan 420111, Russia.
| | - Anna E Rassabina
- Kazan Institute of Biochemistry and Biophysics, Federal Research Center "Kazan Scientific Center of RAS", 2/31 Lobachevsky Street, Box 30, Kazan 420111, Russia
| | - Guzalia F Zakirjanova
- Kazan Institute of Biochemistry and Biophysics, Federal Research Center "Kazan Scientific Center of RAS", 2/31 Lobachevsky Street, Box 30, Kazan 420111, Russia
| | - Nikita S Fedorov
- Kazan Institute of Biochemistry and Biophysics, Federal Research Center "Kazan Scientific Center of RAS", 2/31 Lobachevsky Street, Box 30, Kazan 420111, Russia
| | - Venera R Khabibrakhmanova
- Kazan Institute of Biochemistry and Biophysics, Federal Research Center "Kazan Scientific Center of RAS", 2/31 Lobachevsky Street, Box 30, Kazan 420111, Russia
| | - Ekaterina I Galeeva
- Kazan Institute of Biochemistry and Biophysics, Federal Research Center "Kazan Scientific Center of RAS", 2/31 Lobachevsky Street, Box 30, Kazan 420111, Russia
| | - Eva A Kuznetsova
- Kazan Institute of Biochemistry and Biophysics, Federal Research Center "Kazan Scientific Center of RAS", 2/31 Lobachevsky Street, Box 30, Kazan 420111, Russia
| | - Artem I Malomouzh
- Kazan Institute of Biochemistry and Biophysics, Federal Research Center "Kazan Scientific Center of RAS", 2/31 Lobachevsky Street, Box 30, Kazan 420111, Russia; Kazan National Research Technical University, 10, K. Marx St., Kazan 420111, Russia
| | - Alexey M Petrov
- Kazan Institute of Biochemistry and Biophysics, Federal Research Center "Kazan Scientific Center of RAS", 2/31 Lobachevsky Street, Box 30, Kazan 420111, Russia; Institute of Fundamental Medicine and Biology, Kazan (Volga Region) Federal University, 420008 Kazan, Russia; Kazan State Mediсal University, 49 Butlerova Street, Kazan 420012, Russia.
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Belosludtseva NV, Dubinin MV, Belosludtsev KN. Pore-Forming VDAC Proteins of the Outer Mitochondrial Membrane: Regulation and Pathophysiological Role. BIOCHEMISTRY. BIOKHIMIIA 2024; 89:1061-1078. [PMID: 38981701 DOI: 10.1134/s0006297924060075] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/16/2024] [Revised: 05/12/2024] [Accepted: 05/27/2024] [Indexed: 07/11/2024]
Abstract
Voltage-dependent anion channels (VDAC1-3) of the outer mitochondrial membrane are a family of pore-forming β-barrel proteins that carry out controlled "filtration" of small molecules and ions between the cytoplasm and mitochondria. Due to the conformational transitions between the closed and open states and interaction with cytoplasmic and mitochondrial proteins, VDACs not only regulate the mitochondrial membrane permeability for major metabolites and ions, but also participate in the control of essential intracellular processes and pathological conditions. This review discusses novel data on the molecular structure, regulatory mechanisms, and pathophysiological role of VDAC proteins, as well as future directions in this area of research.
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Affiliation(s)
- Natalia V Belosludtseva
- Institute of Theoretical and Experimental Biophysics, Russian Academy of Sciences, Pushchino, Moscow Region, 142290, Russia
- Mari State University, Yoshkar-Ola, Mari El, 424001, Russia
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Petrov AM. Oxysterols in Central and Peripheral Synaptic Communication. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2024; 1440:91-123. [PMID: 38036877 DOI: 10.1007/978-3-031-43883-7_6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/02/2023]
Abstract
Cholesterol is a key molecule for synaptic transmission, and both central and peripheral synapses are cholesterol rich. During intense neuronal activity, a substantial portion of synaptic cholesterol can be oxidized by either enzymatic or non-enzymatic pathways to form oxysterols, which in turn modulate the activities of neurotransmitter receptors (e.g., NMDA and adrenergic receptors), signaling molecules (nitric oxide synthases, protein kinase C, liver X receptors), and synaptic vesicle cycling involved in neurotransmitters release. 24-Hydroxycholesterol, produced by neurons in the brain, could directly affect neighboring synapses and change neurotransmission. 27-Hydroxycholesterol, which can cross the blood-brain barrier, can alter both synaptogenesis and synaptic plasticity. Increased generation of 25-hydroxycholesterol by activated microglia and macrophages could link inflammatory processes to learning and neuronal regulation. Amyloids and oxidative stress can lead to an increase in the levels of ring-oxidized sterols and some of these oxysterols (4-cholesten-3-one, 5α-cholestan-3-one, 7β-hydroxycholesterol, 7-ketocholesterol) have a high potency to disturb or modulate neurotransmission at both the presynaptic and postsynaptic levels. Overall, oxysterols could be used as "molecular prototypes" for therapeutic approaches. Analogs of 24-hydroxycholesterol (SGE-301, SGE-550, SAGE718) can be used for correction of NMDA receptor hypofunction-related states, whereas inhibitors of cholesterol 24-hydroxylase, cholestane-3β,5α,6β-triol, and cholest-4-en-3-one oxime (olesoxime) can be utilized as potential anti-epileptic drugs and (or) protectors from excitotoxicity.
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Affiliation(s)
- Alexey M Petrov
- Laboratory of Biophysics of Synaptic Processes, Kazan Institute of Biochemistry and Biophysics, Federal Research Center "Kazan Scientific Center of RAS", Kazan, RT, Russia.
- Kazan State Medial University, Kazan, RT, Russia.
- Kazan Federal University, Kazan, RT, Russia.
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Tsentsevitsky AN, Gafurova CR, Mukhutdinova KA, Giniatullin AR, Fedorov NS, Malomouzh AI, Petrov AM. Sphingomyelinase modulates synaptic vesicle mobilization at the mice neuromuscular junctions. Life Sci 2023; 318:121507. [PMID: 36801470 DOI: 10.1016/j.lfs.2023.121507] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2022] [Revised: 02/07/2023] [Accepted: 02/14/2023] [Indexed: 02/21/2023]
Abstract
AIMS Sphingomyelin is an abundant component of the presynaptic membrane and an organizer of lipid rafts. In several pathological conditions, sphingomyelin is hydrolyzed due to an upregulation and release of secretory sphingomyelinases (SMases). Herein, the effects of SMase on exocytotic neurotransmitter release were studied in the diaphragm neuromuscular junctions of mice. MAIN METHODS Microelectrode recordings of postsynaptic potentials and styryl (FM) dyes were used to estimate neuromuscular transmission. Membrane properties were assessed with fluorescent techniques. KEY FINDINGS Application of SMase at a low concentration (0.01 U ml-1) led to a disruption of lipid-packing in the synaptic membranes. Neither spontaneous exocytosis nor evoked neurotransmitter release (in response to single stimuli) were affected by SMase treatment. However, SMase significantly increased neurotransmitter release and the rate of fluorescent FM-dye loss from the synaptic vesicles at 10, 20 and 70 Hz stimulation of the motor nerve. In addition, SMase treatment prevented a shift of the exocytotic mode from "full-collapse" fusion to "kiss-and-run" during high-frequency (70 Hz) activity. The potentiating effects of SMase on neurotransmitter release and FM-dye unloading were suppressed when synaptic vesicle membranes were also exposed to this enzyme (i.e., stimulation occurred during SMase treatment). SIGNIFICANCE Thus, hydrolysis of the plasma membrane sphingomyelin can enhance mobilization of synaptic vesicles and facilitate full fusion mode of exocytosis, but SMase acting on vesicular membrane had a depressant effect on the neurotransmission. Partially, the effects of SMase can be related with the changes in synaptic membrane properties and intracellular signaling.
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Affiliation(s)
- Andrei N Tsentsevitsky
- Laboratory of Biophysics of Synaptic Processes, Kazan Institute of Biochemistry and Biophysics, Federal Research Center "Kazan Scientific Center of RAS", 2/31 Lobachevsky St, Box 30, Kazan, RT 420111, Russia
| | - Chulpan R Gafurova
- Laboratory of Biophysics of Synaptic Processes, Kazan Institute of Biochemistry and Biophysics, Federal Research Center "Kazan Scientific Center of RAS", 2/31 Lobachevsky St, Box 30, Kazan, RT 420111, Russia
| | - Kamilla A Mukhutdinova
- Laboratory of Biophysics of Synaptic Processes, Kazan Institute of Biochemistry and Biophysics, Federal Research Center "Kazan Scientific Center of RAS", 2/31 Lobachevsky St, Box 30, Kazan, RT 420111, Russia
| | - Arthur R Giniatullin
- Laboratory of Biophysics of Synaptic Processes, Kazan Institute of Biochemistry and Biophysics, Federal Research Center "Kazan Scientific Center of RAS", 2/31 Lobachevsky St, Box 30, Kazan, RT 420111, Russia; Kazan State Medial University, 49 Butlerova St., Kazan, RT 420012, Russia
| | - Nikita S Fedorov
- Laboratory of Biophysics of Synaptic Processes, Kazan Institute of Biochemistry and Biophysics, Federal Research Center "Kazan Scientific Center of RAS", 2/31 Lobachevsky St, Box 30, Kazan, RT 420111, Russia
| | - Artem I Malomouzh
- Laboratory of Biophysics of Synaptic Processes, Kazan Institute of Biochemistry and Biophysics, Federal Research Center "Kazan Scientific Center of RAS", 2/31 Lobachevsky St, Box 30, Kazan, RT 420111, Russia
| | - Alexey M Petrov
- Laboratory of Biophysics of Synaptic Processes, Kazan Institute of Biochemistry and Biophysics, Federal Research Center "Kazan Scientific Center of RAS", 2/31 Lobachevsky St, Box 30, Kazan, RT 420111, Russia; Kazan State Medial University, 49 Butlerova St., Kazan, RT 420012, Russia.
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Gafurova CR, Tsentsevitsky AN, Petrov AM. Frequency-Dependent Engagement of Synaptic Vesicle Pools in the Mice Motor Nerve Terminals. Cell Mol Neurobiol 2023; 43:729-739. [PMID: 35113291 DOI: 10.1007/s10571-022-01202-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2021] [Accepted: 01/28/2022] [Indexed: 01/01/2023]
Abstract
Nerve terminals contain numerous synaptic vesicles (SVs) whose exo-endocytic cycling maintains neurotransmitter release. SVs may have different properties, thereby constituting separate pools. However, behavior of SV pools remains elusive in many synapses. To fill this gap, we studied the functioning of SV pools at both low- and higher-frequency stimulations utilizing microelectrode recording and dual-labeling of SVs with FM-dyes at the mice motor nerve terminals. It was found that higher-frequency stimulation caused exocytosis of different kinds of SVs. One type of SVs contributed to exocytosis exclusively at intense activities and their exocytotic rate was depended on the order in which these SVs were recovered by endocytosis. Another type of SVs can sustain the release in response to both low- and higher-frequency stimulations, but increasing activity did not lead to enhanced exocytotic rate of these SVs. In addition, depression of neurotransmitter release induced by 20 Hz stimulation occurred independent on previous episode of 10 Hz activity. We suggest that during prolonged stimulation at least two SV pools can operate. One termed "house-keeping" that would be active at different frequencies and the other termed "plug-in" that would respond to increasing activity.
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Affiliation(s)
- Chulpan R Gafurova
- Laboratory of Biophysics of Synaptic Processes, Kazan Institute of Biochemistry and Biophysics, Federal Research Center "Kazan Scientific Center of RAS", 2/31 Lobachevsky Street, Box 30, Kazan, Russia, 420111
| | - Andrei N Tsentsevitsky
- Laboratory of Biophysics of Synaptic Processes, Kazan Institute of Biochemistry and Biophysics, Federal Research Center "Kazan Scientific Center of RAS", 2/31 Lobachevsky Street, Box 30, Kazan, Russia, 420111
| | - Alexey M Petrov
- Laboratory of Biophysics of Synaptic Processes, Kazan Institute of Biochemistry and Biophysics, Federal Research Center "Kazan Scientific Center of RAS", 2/31 Lobachevsky Street, Box 30, Kazan, Russia, 420111. .,Kazan State Medial University, 49 Butlerova Street, Kazan, Russia, 420012.
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Petrov AM, Zakirjanova GF, Kovyazina IV, Tsentsevitsky AN, Bukharaeva EA. Adrenergic receptors control frequency-dependent switching of the exocytosis mode between "full-collapse" and "kiss-and-run" in murine motor nerve terminal. Life Sci 2022; 296:120433. [PMID: 35219696 DOI: 10.1016/j.lfs.2022.120433] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2021] [Revised: 02/20/2022] [Accepted: 02/21/2022] [Indexed: 12/22/2022]
Abstract
AIMS Neurotransmitter release from the synaptic vesicles can occur through two modes of exocytosis: "full-collapse" or "kiss-and-run". Here we investigated how increasing the nerve activity and pharmacological stimulation of adrenoceptors can influence the mode of exocytosis in the motor nerve terminal. METHODS Recording of endplate potentials with intracellular microelectrodes was used to estimate acetylcholine release. A fluorescent dye FM1-43 and its quenching with sulforhodamine 101 were utilized to visualize synaptic vesicle recycling. KEY FINDINGS An increase in the frequency of stimulation led to a decrease in the rate of FM1-43 unloading despite the higher number of quanta released. High frequency activity promoted neurotransmitter release via the kiss-and-run mechanism. This was confirmed by experiments utilizing (I) FM1-43 dye quencher, that is able to pass into the synaptic vesicle via fusion pore, and (II) loading of FM1-43 by compensatory endocytosis. Noradrenaline and specific α2-adrenoreceptors agonist, dexmedetomidine, controlled the mode of synaptic vesicle recycling at high frequency activity. Their applications favored neurotransmitter release via full-collapse exocytosis rather than the kiss-and-run pathway. SIGNIFICANCE At the diaphragm neuromuscular junctions, neuronal commands are translated into contractions necessary for respiration. During stress, an increase in discharge rate of the phrenic nerve shifts the exocytosis from the full-collapse to the kiss-and-run mode. The stress-related molecule, noradrenaline, restricts neurotransmitter release in response to a high frequency activity, and prevents the shift in the mode of exocytosis through α2-adrenoceptor activation. This may be a component of the mechanism that limits overstimulation of the respiratory system during stress.
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Affiliation(s)
- Alexey M Petrov
- Laboratory of Biophysics of Synaptic Processes, Kazan Institute of Biochemistry and Biophysics, Federal Research Center "Kazan Scientific Center of RAS", Kazan, Russia; Kazan State Medical University, Kazan, Russia.
| | - Guzalia F Zakirjanova
- Laboratory of Biophysics of Synaptic Processes, Kazan Institute of Biochemistry and Biophysics, Federal Research Center "Kazan Scientific Center of RAS", Kazan, Russia
| | - Irina V Kovyazina
- Laboratory of Biophysics of Synaptic Processes, Kazan Institute of Biochemistry and Biophysics, Federal Research Center "Kazan Scientific Center of RAS", Kazan, Russia; Kazan State Medical University, Kazan, Russia
| | - Andrei N Tsentsevitsky
- Laboratory of Biophysics of Synaptic Processes, Kazan Institute of Biochemistry and Biophysics, Federal Research Center "Kazan Scientific Center of RAS", Kazan, Russia
| | - Ellya A Bukharaeva
- Laboratory of Biophysics of Synaptic Processes, Kazan Institute of Biochemistry and Biophysics, Federal Research Center "Kazan Scientific Center of RAS", Kazan, Russia
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Zakyrjanova GF, Tsentsevitsky AN, Kuznetsova EA, Petrov AM. Immune-related oxysterol modulates neuromuscular transmission via non-genomic liver X receptor-dependent mechanism. Free Radic Biol Med 2021; 174:121-134. [PMID: 34391813 DOI: 10.1016/j.freeradbiomed.2021.08.013] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/22/2021] [Revised: 08/08/2021] [Accepted: 08/12/2021] [Indexed: 11/22/2022]
Abstract
Inflammatory reactions induce changes in the neuromuscular system. The mechanisms underlying this link are unclear. Besides cytokines and reactive oxygen species (ROS), production of an antiviral oxysterol 25-hydroxycholesterol (25HC) by immune cells is quickly increased in response to inflammation. Hypothetically, 25HC could contribute to regulation of neuromuscular activity as well as redox status. We found that 25HC (0.01-10 μM) can bidirectionally modulate neurotransmission in mice diaphragm, the main respiratory muscle. Low concentrations (≤0.1 μM) of 25HC reduced involvement of synaptic vesicles (SVs) into exocytosis during 20-Hz activity, whereas higher inflammatory-related concentrations (≥1 μM) had a profound potentiating effect on SV mobilization. The latter stimulatory action of 25HC was accompanied by increase in Ca2+ release from intracellular stores via IP3 receptors. Both increase in SV mobilization and [Ca2+]in were suppressed by a specific antagonist of liver X receptors (LXRs). These receptors formed clusters within the synaptic membranes in a lipid raft-dependent manner. Either raft disruption or intracellular Ca2+ chelation prevented 25HC-mediated acceleration of the exocytotic rate. The same action had inhibition of estrogen receptor α, Gi-protein, Gβγ, phospholipase C and protein kinase C. Additionally, 1 μM 25HC upregulated ROS production in a Ca2+-dependent way and an antioxidant partially decreased the exocytosis-promoting effect of 25HC. Thus, 25HC has prooxidant properties and it is a potent regulator of SV mobilization via activation of lipid raft-associated LXRs which can trigger signaling via estrogen receptor α - Gi-protein - Gβγ - phospholipase C - Ca2+ - protein kinase C pathway. 25HC-mediated increase in ROS may modulate this signaling.
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Affiliation(s)
- Guzel F Zakyrjanova
- Laboratory of Biophysics of Synaptic Processes, Kazan Institute of Biochemistry and Biophysics, Federal Research Center "Kazan Scientific Center of RAS", 2/31 Lobachevsky Street, Box 30, Kazan, 420111, Russia; Department of Normal Physiology, Institute of Neuroscience, Kazan State Medial University, 49 Butlerova Street, Kazan, 420012, Russia
| | - Andrei N Tsentsevitsky
- Laboratory of Biophysics of Synaptic Processes, Kazan Institute of Biochemistry and Biophysics, Federal Research Center "Kazan Scientific Center of RAS", 2/31 Lobachevsky Street, Box 30, Kazan, 420111, Russia
| | - Eva A Kuznetsova
- Laboratory of Biophysics of Synaptic Processes, Kazan Institute of Biochemistry and Biophysics, Federal Research Center "Kazan Scientific Center of RAS", 2/31 Lobachevsky Street, Box 30, Kazan, 420111, Russia
| | - Alexey M Petrov
- Laboratory of Biophysics of Synaptic Processes, Kazan Institute of Biochemistry and Biophysics, Federal Research Center "Kazan Scientific Center of RAS", 2/31 Lobachevsky Street, Box 30, Kazan, 420111, Russia; Department of Normal Physiology, Institute of Neuroscience, Kazan State Medial University, 49 Butlerova Street, Kazan, 420012, Russia.
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Zakyrjanova GF, Giniatullin AR, Mukhutdinova KA, Kuznetsova EA, Petrov AM. Early differences in membrane properties at the neuromuscular junctions of ALS model mice: Effects of 25-hydroxycholesterol. Life Sci 2021; 273:119300. [PMID: 33662433 DOI: 10.1016/j.lfs.2021.119300] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2020] [Revised: 02/13/2021] [Accepted: 02/25/2021] [Indexed: 12/11/2022]
Abstract
AIMS Plasma hyperlipidemia is a protective factor in amyotrophic lateral sclerosis (ALS) while cholesterol-lowering drugs aggravate the pathology. We hypothesize that this phenomenon can be linked with membrane lipid alterations in the neuromuscular junctions (NMJs) occurring before motor neuron loss. METHODS Neurotransmitter release in parallel with lipid membrane properties in diaphragm NMJs of SOD1G93A (mSOD) mice at nine weeks of age (pre-onset stage) were assessed. KEY FINDINGS Despite on slight changes in spontaneous and evoked quantum release of acetylcholine, extracellular levels of choline at resting conditions, an indicator of non-quantum release, were significantly increased in mSOD mice. The use of lipid-sensitive fluorescent probes points to lipid raft disruption in the NMJs of mSOD mice. However, content of cholesterol, a key raft component was unchanged implying another pathway responsible for the loss of raft integrity. In the mSOD mice we found marked increase in levels of raft-destabilizing lipid ceramide. This was accompanied by enhanced ability to uptake of exogenous ceramide in NMJs. Acute and chronic administration of 25-hydroxycholesterol, whose levels increase due to hypercholesterolemia, recovered early alterations in membrane properties. Furthermore, chronic treatment with 25-hydroxycholesterol prevented increase in ceramide and extracellular choline levels as well as suppressed lipid peroxidation of NMJ membranes and fragmentation of end plates. SIGNIFICANCE Thus, lipid raft disruption likely due to ceramide accumulation could be early event in ALS which may trigger neuromuscular abnormalities. Cholesterol derivative 25-hydroxycholesterol may serve as a molecule restoring the membrane and functional properties of NMJs at the early stage.
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Affiliation(s)
- Guzel F Zakyrjanova
- Laboratory of Biophysics of Synaptic Processes, Kazan Institute of Biochemistry and Biophysics, Federal Research Center "Kazan Scientific Center of RAS", 2/31 Lobachevsky Street, box 30, Kazan 420111, Russia; Institute of Neuroscience, Kazan State Medial University, 49 Butlerova Street, Kazan, 420012, Russia
| | - Arthur R Giniatullin
- Department of Normal Physiology, Kazan State Medial University, 49 Butlerova Street, Kazan 420012, Russia
| | - Kamilla A Mukhutdinova
- Institute of Neuroscience, Kazan State Medial University, 49 Butlerova Street, Kazan, 420012, Russia
| | - Eva A Kuznetsova
- Laboratory of Biophysics of Synaptic Processes, Kazan Institute of Biochemistry and Biophysics, Federal Research Center "Kazan Scientific Center of RAS", 2/31 Lobachevsky Street, box 30, Kazan 420111, Russia
| | - Alexey M Petrov
- Laboratory of Biophysics of Synaptic Processes, Kazan Institute of Biochemistry and Biophysics, Federal Research Center "Kazan Scientific Center of RAS", 2/31 Lobachevsky Street, box 30, Kazan 420111, Russia; Institute of Neuroscience, Kazan State Medial University, 49 Butlerova Street, Kazan, 420012, Russia.
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Affiliation(s)
- Andrei N Tsentsevitsky
- Laboratory of Biophysics of Synaptic Processes, Kazan Institute of Biochemistry and Biophysics, Federal Research Center "Kazan Scientific Center of RAS", 2/31 Lobachevsky Street, Box 30, Kazan, 420111, Russia
| | - Alexey M Petrov
- Laboratory of Biophysics of Synaptic Processes, Kazan Institute of Biochemistry and Biophysics, Federal Research Center "Kazan Scientific Center of RAS", 2/31 Lobachevsky Street, Box 30, Kazan, 420111; Institute of Neuroscience, Kazan State Medial University, 49 Butlerova Street, Kazan, 420012, Russia
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11
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Zefirov AL, Mukhametzyanov RD, Zakharov AV, Mukhutdinova KA, Odnoshivkina UG, Petrov AM. Intracellular Acidification Suppresses Synaptic Vesicle Mobilization in the Motor Nerve Terminals. Acta Naturae 2020; 12:105-113. [PMID: 33456982 PMCID: PMC7800596 DOI: 10.32607/actanaturae.11054] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2020] [Accepted: 09/07/2020] [Indexed: 01/27/2023] Open
Abstract
Intracellular protons play a special role in the regulation of presynaptic processes, since the functioning of synaptic vesicles and endosomes depends on their acidification by the H+-pump. Furthermore, transient acidification of the intraterminal space occurs during synaptic activity. Using microelectrode recording of postsynaptic responses (an indicator of neurotransmitter release) and exo-endocytic marker FM1-43, we studied the effects of intracellular acidification with propionate on the presynaptic events underlying neurotransmitter release. Cytoplasmic acidification led to a marked decrease in neurotransmitter release during the first minute of a 20-Hz stimulation in the neuromuscular junctions of mouse diaphragm and frog cutaneous pectoris muscle. This was accompanied by a reduction in the FM1-43 loss during synaptic vesicle exocytosis in response to the stimulation. Estimation of the endocytic uptake of FM1-43 showed no disruption in synaptic vesicle endocytosis. Acidification completely prevented the action of the cell-membrane permeable compound 24-hydroxycholesterol, which can enhance synaptic vesicle mobilization. Thus, the obtained results suggest that an increase in [H+]in negatively regulates neurotransmission due to the suppression of synaptic vesicle delivery to the sites of exocytosis at high activity. This mechanism can be a part of the negative feedback loop in regulating neurotransmitter release.
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Affiliation(s)
- A. L. Zefirov
- Kazan State Medical University, Department of Normal Physiology, Kazan, 420012 Russia
- Institute of Neuroscience, Kazan State Medical University, Kazan, 420012 Russia
| | - R. D. Mukhametzyanov
- Kazan State Medical University, Department of Normal Physiology, Kazan, 420012 Russia
| | - A. V. Zakharov
- Kazan State Medical University, Department of Normal Physiology, Kazan, 420012 Russia
- Kazan Federal University, Kazan, 420008 Russia
| | - K. A. Mukhutdinova
- Institute of Neuroscience, Kazan State Medical University, Kazan, 420012 Russia
| | - U. G. Odnoshivkina
- Kazan State Medical University, Department of Normal Physiology, Kazan, 420012 Russia
| | - A. M. Petrov
- Kazan State Medical University, Department of Normal Physiology, Kazan, 420012 Russia
- Institute of Neuroscience, Kazan State Medical University, Kazan, 420012 Russia
- Laboratory of Biophysics of Synaptic Processes, Kazan Institute of Biochemistry and Biophysics, Federal Research Center “Kazan Scientific Center of RAS”, Kazan, 420111 Russia
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