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Mettlach G, Polo-Parada L, Peca L, Rubin CT, Plattner F, Bibb JA. Enhancement of neuromuscular dynamics and strength behavior using extremely low magnitude mechanical signals in mice. J Biomech 2013; 47:162-7. [PMID: 24157062 DOI: 10.1016/j.jbiomech.2013.09.024] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2013] [Accepted: 09/19/2013] [Indexed: 11/18/2022]
Abstract
Exercise in general, and mechanical signals in particular, help ameliorate the neuromuscular symptoms of aging and possibly other neurodegenerative disorders by enhancing muscle function. To better understand the salutary mechanisms of such physical stimuli, we evaluated the potential for low intensity mechanical signals to promote enhanced muscle dynamics. The effects of daily brief periods of low intensity vibration (LIV) on neuromuscular functions and behavioral correlates were assessed in mice. Physiological analysis revealed that LIV increased isometric force production in semitendinosus skeletal muscle. This effect was evident in both young and old mice. Isometric force recordings also showed that LIV reduced the fatiguing effects of intensive synaptic muscle stimulation. Furthermore, LIV increased evoked neurotransmitter release at neuromuscular synapses but had no effect on spontaneous end plate potential amplitude or frequency. In behavioral studies, LIV increased mouse grip strength and potentiated initial motor activity in a novel environment. These results provide evidence for the efficacy of LIV in producing changes in the neuromuscular system that translate into performance gains at a behavioral scale.
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Affiliation(s)
- Gabriel Mettlach
- Department of Psychiatry, The University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Luis Polo-Parada
- Department of Medical Pharmacology and Physiology, University of Missouri, Dalton Cardiovascular Research Center, Columbia, Missouri, USA
| | - Lauren Peca
- Department of Psychiatry, The University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Clinton T Rubin
- Department of Biomedical Engineering, Stony Brook University, Stony Brook, NY 11794-5281, USA
| | - Florian Plattner
- Department of Psychiatry, The University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - James A Bibb
- Department of Psychiatry, The University of Texas Southwestern Medical Center, Dallas, TX, USA; Department of Neurology and Neurotherapeutics, The University of Texas Southwestern Medical Center, Dallas, TX, USA.
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Jung SY, Kim JM, Kang HK, Jang DH, Min BM. A biologically active sequence of the laminin alpha2 large globular 1 domain promotes cell adhesion through syndecan-1 by inducing phosphorylation and membrane localization of protein kinase Cdelta. J Biol Chem 2009; 284:31764-75. [PMID: 19762914 DOI: 10.1074/jbc.m109.038547] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Laminin-2 promotes basement membrane assembly and peripheral myelinogenesis; however, a receptor-binding motif within laminin-2 and the downstream signaling pathways for motif-mediated cell adhesion have not been fully established. The human laminin-2 alpha2 chain cDNAs cloned from human keratinocytes and fibroblasts correspond to the laminin alpha2 chain variant sequence from the human brain. Individually expressed recombinant large globular (LG) 1 protein promotes cell adhesion and has heparin binding activities. Studies with synthetic peptides delineate the DLTIDDSYWYRI motif (Ln2-P3) within the LG1 as a major site for both heparin and cell binding. Cell adhesion to LG1 and Ln2-P3 is inhibited by treatment of heparitinase I and chondroitinase ABC. Syndecan-1 from PC12 cells binds to LG1 and Ln2-P3 and colocalizes with both molecules. Suppression of syndecan-1 with RNA interference inhibits cell adhesion to LG1 and Ln2-P3. The binding of syndecan-1 with LG1 and Ln2-P3 induces the recruitment of protein kinase Cdelta (PKCdelta) into the membrane and stimulates its tyrosine phosphorylation. A decrease in PKCdelta activity significantly reduces cell adhesion to LG1 and Ln2-P3. Taken together, these results indicate that the Ln2-P3 motif and LG1 domain, containing the motif, within the human laminin-2 alpha2 chain are major ligands for syndecan-1, which mediates cell adhesion through the PKCdelta signaling pathway.
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Affiliation(s)
- Sung Youn Jung
- Department of Oral Biochemistry and Program of Craniomaxillofacial Reconstruction Science, Dental Research Institute, Intellectual Biointerface Engineering Center, BK21 CLS, Seoul National University School of Dentistry, Seoul 110-749, Korea
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Anderson JL, Head SI, Morley JW. Synaptic plasticity in the dy2J mouse model of laminin alpha2-deficient congenital muscular dystrophy. Brain Res 2005; 1042:23-8. [PMID: 15823249 DOI: 10.1016/j.brainres.2005.02.001] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2004] [Accepted: 02/01/2005] [Indexed: 11/18/2022]
Abstract
Laminin alpha2-deficient congenital muscular dystrophy is a debilitating disease affecting both muscle and neural tissue as a result of mutations in the LAMA2 gene. It presents at or soon after birth with muscle weakness and is further characterised by clinical central nervous system involvement. Laminin alpha2 is part of the extracellular matrix, linked to the cellular cystoskeleton via dystroglycan which is an integral part of the dystrophin-glycoprotein complex (DGC). We examined both short- and long-term synaptic plasticity in the C57BL6J/dy(2J) mouse, an animal model of laminin alpha2 deficient congenital muscular dystrophy. Using a cerebellar slice preparation, we show that the pre-synaptically mediated paired-pulse facilitation (PPF) was no different between dy(2J) and littermate controls. Approximately half (7/12) the dy(2J) Purkinje cells displayed a blunted LTD compared to littermate controls, and one third (4/12) of dy(2J) Purkinje cells displayed LTP. This study demonstrates that a defective laminin alpha2 causes a disruption in long-term synaptic plasticity at the Purkinje cell-parallel fibre synapse.
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Affiliation(s)
- J L Anderson
- School of Medical Sciences, University of New South Wales, 2052, Australia
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Everett AW, Ernst EJ. Increased quantal size in transmission at slow but not fast neuromuscular synapses of apolipoprotein E deficient mice. Exp Neurol 2004; 185:290-6. [PMID: 14736510 DOI: 10.1016/j.expneurol.2003.10.006] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Uncertainties from the literature concerning the role of apolipoprotein E (apoE) in central cholinergic function prompted us to investigate what effect apoE may have on transmission at the neuromuscular junction. Both spontaneous and evoked release were measured in isolated extensor digitorum longus (edl) and soleus muscles from both wild-type and apoE-deficient mice. Miniature endplate and nerve-evoked endplate potentials (MEPPs and EPPs, respectively) were indistinguishable in edl muscles in both groups of mice; however, MEPP amplitudes in soleus muscles were significantly larger (by an average of 23%) in apoE-deficient mice compared with 5- to 7-week-old age-matched wild-type mice. The EPP amplitudes were also larger in soleus muscles in the mutant mice, but this was a reflection of the larger quantal size in this muscle because quantal content, determined from the ratio of the average EPP amplitude to average MEPP amplitude, was unchanged from normal in the mutant mice. The MEPP frequency and the percent of nerve stimulations failing to produce an EPP were unchanged from normal in both muscle types in the mutant mice. The difference in quantal size in soleus muscle transmission between mutant and wild-type mice was abolished in the presence of neostigmine, an acetylcholinesterase inhibitor. The results suggest that apoE normally associates with acetylcholinesterase in the synaptic cleft of slow muscles, modulating the activity of the enzyme and therefore quantal size.
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Affiliation(s)
- A W Everett
- Physiology, M311, School of Biomedical and Chemical Sciences, The University of Western Australia, Crawley 6009, Australia.
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van Lunteren E, Moyer M. Sternohyoid muscle fatigue properties of dy/dy dystrophic mice, an animal model of merosin-deficient congenital muscular dystrophy. Pediatr Res 2003; 54:547-53. [PMID: 12840158 DOI: 10.1203/01.pdr.0000081762.51546.16] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Humans with merosin-deficient congenital muscular dystrophy have both sucking problems during infancy and sleep-disordered breathing during childhood. We hypothesized that merosin-deficient pharyngeal muscles fatigue faster than normal muscles. This was tested in vitro using sternohyoid muscle from an animal model of this disease, the dy/dy dystrophic mouse. Isometric twitch contraction and half-relaxation times were similar for dy/dy and normal sternohyoid. However, rate of force loss during repetitive 25-Hz train stimulation was markedly diminished in dystrophic compared with normal sternohyoid muscle. Furthermore, force potentiation, which occurred during the early portion of the fatigue-inducing stimulation, had a longer duration in dystrophic compared with normal muscle (approximately 60 versus 20 s). As a result of these two processes, at the end of 2 min of stimulation, force of dystrophic muscle had decreased by 8 +/- 5% and that of normal muscle by 69 +/- 4% (p < 0.0001). The potassium-channel blocker, 3,4-diaminopyridine, increased force of dy/dy sternohyoid muscle during twitch and 25-Hz contractions by 148 +/- 20% (p < 0.00001) and 109 +/- 18% (p < 0.00002), respectively. During repetitive 25-Hz stimulation, force of 3,4-diaminopyridine-treated dystrophic muscle remained significantly higher than that of untreated muscle, despite the early force potentiation being eliminated and fatigue being accelerated. Thus, merosin deficiency reduces fatigue and prolongs the duration of force potentiation. The latter alterations may partially preserve the integrity of upper airway muscle function, without which the severity of pharyngeal complications (feeding problems, sleep-related respiratory dysfunction) might be even more pronounced in the human merosin-deficient congenital muscular dystrophies.
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Affiliation(s)
- Erik van Lunteren
- Department of Medicine, Cleveland VA Medical Center, Cleveland, OH 44106, USA.
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Affiliation(s)
- Joshua R Sanes
- Department of Anatomy and Neurobiology, Washington University Medical School, St. Louis, Missouri 63110, USA.
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Smirnov SP, McDearmon EL, Li S, Ervasti JM, Tryggvason K, Yurchenco PD. Contributions of the LG modules and furin processing to laminin-2 functions. J Biol Chem 2002; 277:18928-37. [PMID: 11886875 DOI: 10.1074/jbc.m201880200] [Citation(s) in RCA: 75] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
The alpha2-laminin subunit contributes to basement membrane functions in muscle, nerve, and other tissues, and mutations in its gene are causes of congenital muscular dystrophy. The alpha2 G-domain modules, mutated in several of these disorders, are thought to mediate different cellular interactions. To analyze these contributions, we expressed recombinant laminin-2 (alpha(2)beta(1)gamma(1)) with LG4-5, LG1-3, and LG1-5 modular deletions. Wild-type and LG4-5 deleted-laminins were isolated from medium intact and cleaved within LG3 by a furin-like convertase. Myoblasts adhered predominantly through LG1-3 while alpha-dystroglycan bound to both LG1-3 and LG4-5. Recombinant laminin stimulated acetylcholine receptor (AChR) clustering; however, clustering was induced only by the proteolytic processed form, even in the absence of LG4-5. Furthermore, clustering required alpha(6)beta(1) integrin and alpha-dystroglycan binding activities available on LG1-3, acting in concert with laminin polymerization. The ability of the modified laminins to mediate basement membrane assembly was also evaluated in embryoid bodies where it was found that both LG1-3 and LG4-5, but not processing, were required. In conclusion, there is a division of labor among LG-modules in which (i) LG4-5 is required for basement membrane assembly but not for AChR clustering, and (ii) laminin-induced AChR clustering requires furin cleavage of LG3 as well as alpha-dystroglycan and alpha(6)beta(1) integrin binding.
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Affiliation(s)
- Sergei P Smirnov
- Department of Pathology & Laboratory Medicine, Robert Wood Johnson Medical School, Piscataway, New Jersey 08854, USA
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García-Ayllón MS, Campoy FJ, Vidal CJ, Muñoz-Delgado E. Identification of inactive ecto-5'-nucleotidase in normal mouse muscle and its increased activity in dystrophic Lama2(dy) mice. J Neurosci Res 2001; 66:656-65. [PMID: 11746385 DOI: 10.1002/jnr.10014] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Ecto-5'-nucleotidase (eNT) activity and protein in normal (NM) and merosin-deficient dystrophic (DM) Lama2(dy) mice muscle were studied. eNT activity in DM was three- to four-fold that in NM. eNT in NM and DM displayed the same kinetic properties. Slot and Western blotting revealed that the immunoreactive protein was two to three times more abundant in control muscle, when NM and DM samples with the same eNT activity were compared, indicating that mouse muscle contains catalytically inactive eNT components. eNT activity and protein peaks coincided in sedimentation analyses, revealing that inactive eNT occurs as dimers. Most eNT activity and protein of NM bound to Lens culinaris (LCA) or Ricinus communis (RCA) agglutinins, but half of the activity and one-third of the protein bound to wheat germ agglutinin (WGA). Although WGA interaction did not permit full separation of inactive eNT, the results suggest that similar proportions of active species with and without WGA reactivity occur in mouse muscle, whereas a great fraction of the inactive eNT variants lack WGA reactivity. Because the level of eNT protein was little modified in DM, the higher eNT activity in dystrophic than in control muscle may result from misregulation in the synthesis of active and inactive eNT species or from conversion of inactive into active components.
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Affiliation(s)
- M S García-Ayllón
- Departamento de Bioquímica y Biología Molecular-A, Universidad de Murcia, Espinardo, Murcia, Spain
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Lewis MP, Machell JR, Hunt NP, Sinanan AC, Tippett HL. The extracellular matrix of muscle--implications for manipulation of the craniofacial musculature. Eur J Oral Sci 2001; 109:209-21. [PMID: 11531066 DOI: 10.1034/j.1600-0722.2001.00021.x] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Successful adaptation of craniofacial skeletal muscle is dependent upon the connective tissue component of the muscle. This is exemplified by procedures such as distraction histo/osteogenesis. The mechanisms underlying remodelling of intramuscular connective tissue are complex and multifactorial and involve extracellular matrix (ECM) molecules, receptors for the ECM (integrins) and enzymes that remodel the ECM (MMPs). This review discusses the current state of knowledge and clinical implications of connective tissue biology as applied to craniofacial skeletal muscle.
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Affiliation(s)
- M P Lewis
- Department of Orthodontics, Eastman Dental Institute, University College London, UK.
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Abstract
The laminins are a family of glycoproteins that provide an integral part of the structural scaffolding of basement membranes in almost every animal tissue. Each laminin is a heterotrimer assembled from alpha, beta, and gamma chain subunits, secreted and incorporated into cell-associated extracellular matrices. The laminins can self-assemble, bind to other matrix macromolecules, and have unique and shared cell interactions mediated by integrins, dystroglycan, and other receptors. Through these interactions, laminins critically contribute to cell differentiation, cell shape and movement, maintenance of tissue phenotypes, and promotion of tissue survival. Recent advances in the characterization of genetic disruptions in humans, mice, nematodes and flies have revealed developmental roles for the different laminin subunits in diverse cell types, affecting differentiation from blastocyst formation to the post-natal period. These genetic defects have challenged some of the previous concepts about basement membranes and have shed new light on the diversity and complexity of laminin functions as well as established the molecular basis of several human diseases.
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Affiliation(s)
- H Colognato
- Department of Pathology & Laboratory Medicine, Robert Wood Johnson Medical School, Piscataway, NJ 08854, USA
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Abstract
Primary and secondary defects in extracellular matrix proteins emphasize the role of these proteins in neuromuscular disorders; mutations have been found in the genes for the laminin-alpha 2 chain, for all three alpha chains of collagen VI and for integrin alpha 2. Secondary alterations in protein expression occur in association with these primary defects, and in other disorders they implicate the extracellular matrix. Animal models are helping to elucidate the function of some of these proteins, to develop therapeutic strategies and to suggest candidate proteins for other neuromuscular disorders.
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Affiliation(s)
- C A Sewry
- Neuromuscular Unit, Imperial College School of Medicine, Hammersmith Hospital, London, UK.
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