1
|
Zelada D, Barrantes FJ, Henríquez JP. Lithium causes differential effects on postsynaptic stability in normal and denervated neuromuscular synapses. Sci Rep 2021; 11:17285. [PMID: 34446751 PMCID: PMC8390761 DOI: 10.1038/s41598-021-96708-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2021] [Accepted: 08/06/2021] [Indexed: 11/12/2022] Open
Abstract
Lithium chloride has been widely used as a therapeutic mood stabilizer. Although cumulative evidence suggests that lithium plays modulatory effects on postsynaptic receptors, the underlying mechanism by which lithium regulates synaptic transmission has not been fully elucidated. In this work, by using the advantageous neuromuscular synapse, we evaluated the effect of lithium on the stability of postsynaptic nicotinic acetylcholine receptors (nAChRs) in vivo. We found that in normally innervated neuromuscular synapses, lithium chloride significantly decreased the turnover of nAChRs by reducing their internalization. A similar response was observed in CHO-K1/A5 cells expressing the adult muscle-type nAChRs. Strikingly, in denervated neuromuscular synapses, lithium led to enhanced nAChR turnover and density by increasing the incorporation of new nAChRs. Lithium also potentiated the formation of unstable nAChR clusters in non-synaptic regions of denervated muscle fibres. We found that denervation-dependent re-expression of the foetal nAChR γ-subunit was not altered by lithium. However, while denervation inhibits the distribution of β-catenin within endplates, lithium-treated fibres retain β-catenin staining in specific foci of the synaptic region. Collectively, our data reveal that lithium treatment differentially affects the stability of postsynaptic receptors in normal and denervated neuromuscular synapses in vivo, thus providing novel insights into the regulatory effects of lithium on synaptic organization and extending its potential therapeutic use in conditions affecting the peripheral nervous system.
Collapse
Affiliation(s)
- Diego Zelada
- Neuromuscular Studies Laboratory (NeSt Lab), Department of Cell Biology, CMA Bio-Bio, Facultad de Ciencias Biológicas, Universidad de Concepción, Casilla 160-C, Concepción, Chile
| | - Francisco J Barrantes
- Pontificia Universidad Católica Argentina (UCA)-Scientific and Technological Research Council of Argentina (CONICET), Buenos Aires, Argentina
| | - Juan Pablo Henríquez
- Neuromuscular Studies Laboratory (NeSt Lab), Department of Cell Biology, CMA Bio-Bio, Facultad de Ciencias Biológicas, Universidad de Concepción, Casilla 160-C, Concepción, Chile.
| |
Collapse
|
2
|
Ojeda J, Bermedo-García F, Pérez V, Mella J, Hanna P, Herzberg D, Tejero R, López-Manzaneda M, Tabares L, Henríquez JP. The Mouse Levator Auris Longus Muscle: An Amenable Model System to Study the Role of Postsynaptic Proteins to the Maintenance and Regeneration of the Neuromuscular Synapse. Front Cell Neurosci 2020; 14:225. [PMID: 32848618 PMCID: PMC7405910 DOI: 10.3389/fncel.2020.00225] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2020] [Accepted: 06/26/2020] [Indexed: 12/16/2022] Open
Abstract
The neuromuscular junction (NMJ) is the peripheral synapse that controls the coordinated movement of many organisms. The NMJ is also an archetypical model to study synaptic morphology and function. As the NMJ is the primary target of neuromuscular diseases and traumatic injuries, the establishment of suitable models to study the contribution of specific postsynaptic muscle-derived proteins on NMJ maintenance and regeneration is a permanent need. Considering the unique experimental advantages of the levator auris longus (LAL) muscle, here we present a method allowing for efficient electroporation-mediated gene transfer and subsequent detailed studies of the morphology and function of the NMJ and muscle fibers. Also, we have standardized efficient facial nerve injury protocols to analyze LAL muscle NMJ degeneration and regeneration. Our results show that the expression of a control fluorescent protein does not alter either the muscle structural organization, the apposition of the pre- and post-synaptic domains, or the functional neurotransmission parameters of the LAL muscle NMJs; in turn, the overexpression of MuSK, a major regulator of postsynaptic assembly, induces the formation of ectopic acetylcholine receptor clusters. Our NMJ denervation experiments showed complete reinnervation of LAL muscle NMJs four weeks after facial nerve injury. Together, these experimental strategies in the LAL muscle constitute effective methods to combine protein expression with accurate analyses at the levels of structure, function, and regeneration of the NMJ.
Collapse
Affiliation(s)
- Jorge Ojeda
- Neuromuscular Studies Laboratory (NeSt Lab), Department of Cell Biology, Faculty of Biological Sciences, Center for Advanced Microscopy (CMA BioBio), Universidad de Concepción, Concepción, Chile.,Department of Medical Physiology and Biophysics, School of Medicine, Universidad de Sevilla, Sevilla, Spain.,Developmental Neurobiology Unit, Biomedical Sciences Research Laboratory, Basic Sciences Department, Faculty of Medicine, Universidad Católica de la Santísima Concepción, Concepción, Chile
| | - Francisca Bermedo-García
- Neuromuscular Studies Laboratory (NeSt Lab), Department of Cell Biology, Faculty of Biological Sciences, Center for Advanced Microscopy (CMA BioBio), Universidad de Concepción, Concepción, Chile
| | - Viviana Pérez
- Neuromuscular Studies Laboratory (NeSt Lab), Department of Cell Biology, Faculty of Biological Sciences, Center for Advanced Microscopy (CMA BioBio), Universidad de Concepción, Concepción, Chile
| | - Jessica Mella
- Neuromuscular Studies Laboratory (NeSt Lab), Department of Cell Biology, Faculty of Biological Sciences, Center for Advanced Microscopy (CMA BioBio), Universidad de Concepción, Concepción, Chile
| | - Patricia Hanna
- Neuromuscular Studies Laboratory (NeSt Lab), Department of Cell Biology, Faculty of Biological Sciences, Center for Advanced Microscopy (CMA BioBio), Universidad de Concepción, Concepción, Chile
| | - Daniel Herzberg
- Veterinary Sciences Clinic, Universidad de Concepción, Concepción, Chile
| | - Rocío Tejero
- Department of Medical Physiology and Biophysics, School of Medicine, Universidad de Sevilla, Sevilla, Spain
| | - Mario López-Manzaneda
- Department of Medical Physiology and Biophysics, School of Medicine, Universidad de Sevilla, Sevilla, Spain
| | - Lucia Tabares
- Department of Medical Physiology and Biophysics, School of Medicine, Universidad de Sevilla, Sevilla, Spain
| | - Juan Pablo Henríquez
- Neuromuscular Studies Laboratory (NeSt Lab), Department of Cell Biology, Faculty of Biological Sciences, Center for Advanced Microscopy (CMA BioBio), Universidad de Concepción, Concepción, Chile
| |
Collapse
|
3
|
Ivannikov MV, Van Remmen H. Sod1 gene ablation in adult mice leads to physiological changes at the neuromuscular junction similar to changes that occur in old wild-type mice. Free Radic Biol Med 2015; 84:254-262. [PMID: 25841780 PMCID: PMC4762177 DOI: 10.1016/j.freeradbiomed.2015.03.021] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/14/2014] [Revised: 03/16/2015] [Accepted: 03/18/2015] [Indexed: 12/27/2022]
Abstract
Reactive oxygen species (ROS) are believed to be important mediators of muscle atrophy and weakness in aging and many degenerative conditions. However, the mechanisms and physiological processes specifically affected by elevated ROS in neuromuscular units that contribute to muscle weakness during aging are not well defined. Here we investigate the effects of chronic oxidative stress on neurotransmission and excitation-contraction (EC) coupling mechanisms in the levator auris longus (LAL) muscle from young (4-8 months) and old (22-28 months) wild-type mice and young adult Cu-Zn superoxide dismutase 1 knockout (Sod1(-/-)) mice. The frequency of spontaneous neurotransmitter release and the amplitude of evoked neurotransmitter release in young Sod1(-/-) and old wild-type LAL neuromuscular junctions were significantly reduced from the young wild-type values, and those declines were mirrored by decreases in synaptic vesicle pool size. Presynaptic cytosolic calcium concentration and mitochondrial calcium uptake amplitudes showed substantial increases in stimulated young Sod1(-/-) and old axon terminals. Surprisingly, LAL muscle fibers from old mice showed a greater excitability than fibers from either young wild-type or young Sod1(-/-) LAL. Both evoked excitatory junction potential (EJP) and spontaneous mini EJP amplitudes were considerably higher in LAL muscles from old mice than in fibers from young Sod1(-/-) LAL muscle. Despite a greater excitability, sarcoplasmic calcium influx in both old wild-type and young Sod1(-/-) LAL muscle fibers was significantly less. Sarcoplasmic reticulum calcium levels were also reduced in both old wild-type and young Sod1(-/-) mice, but the difference was not statistically significant in muscle fibers from old wild-type mice. The protein ratio of triad calcium channels RyR1/DHPR was not different in all groups. However, fibers from both young Sod1(-/-) and old mice had substantially elevated levels of protein carbonylation and S-nitrosylation modifications. Overall, our results suggest that young Sod1(-/-) recapitulate many neuromuscular and muscle fiber changes seen in old mice. We also conclude that muscle weakness in old mice might in part be driven by ROS-mediated EC uncoupling, while both EC uncoupling and reduced neurotransmitter release contribute to muscle weakness in Sod1(-/-) mice.
Collapse
Affiliation(s)
- Maxim V Ivannikov
- Department of Neuroscience and Physiology, NYU School of Medicine, 550 First Avenue, New York, NY 10016, USA.
| | - Holly Van Remmen
- Free Radical Biology and Aging Program, Oklahoma Medical Research Foundation, 825 NE 13th Street, Oklahoma City, OK 73104, USA.
| |
Collapse
|
4
|
Murray L, Gillingwater TH, Kothary R. Dissection of the transversus abdominis muscle for whole-mount neuromuscular junction analysis. J Vis Exp 2014:e51162. [PMID: 24457471 PMCID: PMC4089412 DOI: 10.3791/51162] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Abstract
Analysis of neuromuscular junction morphology can give important insight into the physiological status of a given motor neuron. Analysis of thin flat muscles can offer significant advantage over traditionally used thicker muscles, such as those from the hind limb (e.g. gastrocnemius). Thin muscles allow for comprehensive overview of the entire innervation pattern for a given muscle, which in turn permits identification of selectively vulnerable pools of motor neurons. These muscles also allow analysis of parameters such as motor unit size, axonal branching, and terminal/nodal sprouting. A common obstacle in using such muscles is gaining the technical expertise to dissect them. In this video, we detail the protocol for dissecting the transversus abdominis (TVA) muscle from young mice and performing immunofluorescence to visualize axons and neuromuscular junctions (NMJs). We demonstrate that this technique gives a complete overview of the innervation pattern of the TVA muscle and can be used to investigate NMJ pathology in a mouse model of the childhood motor neuron disease, spinal muscular atrophy.
Collapse
Affiliation(s)
- Lyndsay Murray
- Regenerative Medicine Program, Ottawa Hospital Research Institute
| | | | | |
Collapse
|