Tabla espec. clave
|Species Reactivity||Key Applications||Host||Format||Antibody Type|
|H, Mk, Rb||ELISA, CULT, IF, IHC, IP, WB||M||Ascites||Monoclonal Antibody|
|Presentation||Unpurified ascites in buffer containing no preservatives.|
|Safety Information according to GHS|
|Material Size||100 µL|
Ficha datos de seguridad (MSDS)
Referencias bibliográficas | 38 Disponible | Ver todas las referencias
|Visión general referencias||Aplicación||Especie||Pub Med ID|
|Resistance exercise increases active MMP and β1-integrin protein expression in skeletal muscle. |
Ogasawara, R; Nakazato, K; Sato, K; Boppart, MD; Fujita, S
Physiological reports 2 2014
Recent studies indicate that matrix metalloproteinases (MMPs) and critical linkage proteins in the extracellular matrix (ECM) regulate skeletal muscle mass, although the effects of resistance training (RT) on protein expression and activity are unclear. Thus, the purpose of the present study was to investigate the effects of RT on MMP activity and expression of ECM-related proteins. Ten male Sprague-Dawley rats were randomly assigned to 1 bout (1B) or 18 bouts (18B) of electrical stimulation. The right gastrocnemius muscle was isometrically contracted via percutaneous electrical stimulation (five sets of 5 sec stimulation × five contractions/set with 5 sec interval between contractions and 3 min rest between sets) once (1B) or every other day for 5 weeks (18B). The left leg served as a control. Activity of MMP-2 and MMP-9, determined via gelatin zymography, was increased (P less than 0.05) immediately after 1B. However, MMP activation was not evident following 18B. No changes in collagen IV, laminin α2, α7-integrin, or ILK protein expression were detected immediately following 1B or 18B. However, β1-integrin protein expression was significantly increased (P less than 0.05) with 18B. Our results suggest that resistance exercise activates MMPs during the initial phase of RT but this response is attenuated with continuation of RT.
|ISPD gene mutations are a common cause of congenital and limb-girdle muscular dystrophies. |
Cirak, S; Foley, AR; Herrmann, R; Willer, T; Yau, S; Stevens, E; Torelli, S; Brodd, L; Kamynina, A; Vondracek, P; Roper, H; Longman, C; Korinthenberg, R; Marrosu, G; Nürnberg, P; , ; Michele, DE; Plagnol, V; Hurles, M; Moore, SA; Sewry, CA; Campbell, KP; Voit, T; Muntoni, F
Brain : a journal of neurology 136 269-81 2013
Dystroglycanopathies are a clinically and genetically diverse group of recessively inherited conditions ranging from the most severe of the congenital muscular dystrophies, Walker-Warburg syndrome, to mild forms of adult-onset limb-girdle muscular dystrophy. Their hallmark is a reduction in the functional glycosylation of α-dystroglycan, which can be detected in muscle biopsies. An important part of this glycosylation is a unique O-mannosylation, essential for the interaction of α-dystroglycan with extracellular matrix proteins such as laminin-α2. Mutations in eight genes coding for proteins in the glycosylation pathway are responsible for ∼50% of dystroglycanopathy cases. Despite multiple efforts using traditional positional cloning, the causative genes for unsolved dystroglycanopathy cases have escaped discovery for several years. In a recent collaborative study, we discovered that loss-of-function recessive mutations in a novel gene, called isoprenoid synthase domain containing (ISPD), are a relatively common cause of Walker-Warburg syndrome. In this article, we report the involvement of the ISPD gene in milder dystroglycanopathy phenotypes ranging from congenital muscular dystrophy to limb-girdle muscular dystrophy and identified allelic ISPD variants in nine cases belonging to seven families. In two ambulant cases, there was evidence of structural brain involvement, whereas in seven, the clinical manifestation was restricted to a dystrophic skeletal muscle phenotype. Although the function of ISPD in mammals is not yet known, mutations in this gene clearly lead to a reduction in the functional glycosylation of α-dystroglycan, which not only causes the severe Walker-Warburg syndrome but is also a common cause of the milder forms of dystroglycanopathy.
|Mutations in B3GALNT2 cause congenital muscular dystrophy and hypoglycosylation of α-dystroglycan. |
Stevens, E; Carss, KJ; Cirak, S; Foley, AR; Torelli, S; Willer, T; Tambunan, DE; Yau, S; Brodd, L; Sewry, CA; Feng, L; Haliloglu, G; Orhan, D; Dobyns, WB; Enns, GM; Manning, M; Krause, A; Salih, MA; Walsh, CA; Hurles, M; Campbell, KP; Manzini, MC; , ; Stemple, D; Lin, YY; Muntoni, F
American journal of human genetics 92 354-65 2013
Mutations in several known or putative glycosyltransferases cause glycosylation defects in α-dystroglycan (α-DG), an integral component of the dystrophin glycoprotein complex. The hypoglycosylation reduces the ability of α-DG to bind laminin and other extracellular matrix ligands and is responsible for the pathogenesis of an inherited subset of muscular dystrophies known as the dystroglycanopathies. By exome and Sanger sequencing we identified two individuals affected by a dystroglycanopathy with mutations in β-1,3-N-acetylgalactosaminyltransferase 2 (B3GALNT2). B3GALNT2 transfers N-acetyl galactosamine (GalNAc) in a β-1,3 linkage to N-acetyl glucosamine (GlcNAc). A subsequent study of a separate cohort of individuals identified recessive mutations in four additional cases that were all affected by dystroglycanopathy with structural brain involvement. We show that functional dystroglycan glycosylation was reduced in the fibroblasts and muscle (when available) of these individuals via flow cytometry, immunoblotting, and immunocytochemistry. B3GALNT2 localized to the endoplasmic reticulum, and this localization was perturbed by some of the missense mutations identified. Moreover, knockdown of b3galnt2 in zebrafish recapitulated the human congenital muscular dystrophy phenotype with reduced motility, brain abnormalities, and disordered muscle fibers with evidence of damage to both the myosepta and the sarcolemma. Functional dystroglycan glycosylation was also reduced in the b3galnt2 knockdown zebrafish embryos. Together these results demonstrate a role for B3GALNT2 in the glycosylation of α-DG and show that B3GALNT2 mutations can cause dystroglycanopathy with muscle and brain involvement.
|Clinical and molecular characterization of limb-girdle muscular dystrophy due to LAMA2 mutations. |
Gavassini BF, Carboni N, Nielsen JE, Danielsen ER, Thomsen C, Svenstrup K, Bello L, Maioli MA, Marrosu G, Ticca AF, Mura M, Marrosu MG, Soraru G, Angelini C, Vissing J, Pegoraro E.
Muscle & nerve 44 703-9 2011
In this study we describe the clinical and molecular characteristics of limb-girdle muscular dystrophy (LGMD) due to LAMA2 mutations.
|The contribution of human synovial stem cells to skeletal muscle regeneration. |
Meng J, Adkin CF, Arechavala-Gomeza V, Boldrin L, Muntoni F, Morgan JE
Neuromuscul Disord 20 6-15. 2010
Stem cell therapy holds promise for treating muscle diseases. Although satellite cells regenerate skeletal muscle, they only have a local effect after intra-muscular transplantation. Alternative cell types, more easily obtainable and systemically-deliverable, were therefore sought. Human synovial stem cells (hSSCs) have been reported to regenerate muscle fibres and reconstitute the satellite cell pool. We therefore determined if these cells are able to regenerate skeletal muscle after intra-muscular injection into cryodamaged muscles of Rag2-/gamma chain-/C5-mice. We found that hSSCs possess only limited capacity to undergo myogenic differentiation in vitro or to contribute to muscle regeneration in vivo. However, this is enhanced by over-expression of human MyoD1. Interestingly, hSSCs express extracellular matrix components laminin alpha2 and collagen VI within grafted muscles. Therefore, despite their limited capacity to regenerate skeletal muscle, hSSCs could play a role in treating muscular dystrophies secondary to defects in extracellular matrix proteins.
|Immunohistochemical analysis of calpain 3: advantages and limitations in diagnosing LGMD2A. |
Richard Charlton,Matthew Henderson,Julie Richards,Judith Hudson,Volker Straub,Kate Bushby,Rita Barresi
Neuromuscular disorders : NMD 19 2009
Immunoblot is currently the preferred laboratory test to assist the diagnosis of limb-girdle muscular dystrophy (LGMD) 2A (calpainopathy). To assess whether immunohistochemistry may offer a reliable alternative screening we used two antibodies, Calp3-2C4 (exon 1) and Calp3-12A2 (exon 8), to label blots and sections of skeletal muscle from controls and patients with LGMD2A and other muscle diseases. In LGMD2A muscle biopsies a high degree of concordance was found with Calp3-2C4: labelling on sections was absent in patients with no bands on immunoblot and detected in those where CAPN3 bands were seen. Calp3-12A2 results were less consistent, with most samples retaining labelling. Interestingly, CAPN3 was found in all muscle sections from disease control patients irrespective of its detection on immunoblot. Our results show that immunohistochemistry with Calp3-2C4 has a similar pickup rate of LGMD2A as immunoblot and it may therefore be useful for distinguishing the majority of genuine CAPN3 defects from secondary protein reduction. However immunoblot is still needed when CAPN3 is present on sections to show secondary CAPN3 reduction and to identify LGMD2A with variable reduction of CAPN3 bands.
|A comparative study of alpha-dystroglycan glycosylation in dystroglycanopathies suggests that the hypoglycosylation of alpha-dystroglycan does not consistently correlate with clinical severity. |
Cecilia Jimenez-Mallebrera,Silvia Torelli,Lucy Feng,Jihee Kim,Caroline Godfrey,Emma Clement,Rachael Mein,Stephen Abbs,Susan C Brown,Kevin P Campbell,Stephan Kröger,Beril Talim,Haluk Topaloglu,Ros Quinlivan,Helen Roper,Anne M Childs,Maria Kinali,Caroline A Sewry,Francesco Muntoni
Brain pathology (Zurich, Switzerland) 19 2009
Hypoglycosylation of alpha-dystroglycan underpins a subgroup of muscular dystrophies ranging from congenital onset of weakness, severe brain malformations and death in the perinatal period to mild weakness in adulthood without brain involvement. Mutations in six genes have been identified in a proportion of patients. POMT1, POMT2 and POMGnT1 encode for glycosyltransferases involved in the mannosylation of alpha-dystroglycan but the function of fukutin, FKRP and LARGE is less clear. The pathological hallmark is reduced immunolabeling of skeletal muscle with antibodies recognizing glycosylated epitopes on alpha-dystroglycan. If the common pathway of these conditions is the hypoglycosyation of alpha-dystroglycan, one would expect a correlation between clinical severity and the extent of hypoglycosylation. By studying 24 patients with mutations in these genes, we found a good correlation between reduced alpha-dystroglycan staining and clinical course in patients with mutations in POMT1, POMT2 and POMGnT1. However, this was not always the case in patients with defects in fukutin and FKRP, as we identified patients with mild limb-girdle phenotypes without brain involvement with profound depletion of alpha-dystroglycan. These data indicate that it is not always possible to correlate clinical course and alpha-dystroglycan labeling and suggest that there might be differences in alpha-dystroglycan processing in these disorders.Artículo Texto completo
|Diagnosis and etiology of congenital muscular dystrophy. |
R A Peat, J M Smith, A G Compton, N L Baker, R A Pace, D J Burkin, S J Kaufman, S R Lamandé, K N North
Neurology 71 312-21 2008
OBJECTIVE: We aimed to determine the frequency of all known forms of congenital muscular dystrophy (CMD) in a large Australasian cohort. METHODS: We screened 101 patients with CMD with a combination of immunofluorescence, Western blotting, and DNA sequencing to identify disease-associated abnormalities in glycosylated alpha-dystroglycan, collagen VI, laminin alpha2, alpha7-integrin, and selenoprotein. RESULTS: A total of 45% of the CMD cohort were assigned to an immunofluorescent subgroup based on their abnormal staining pattern. Abnormal staining for glycosylated alpha-dystroglycan was present in 25% of patients, and approximately half of these had reduced glycosylated alpha-dystroglycan by Western blot. Sequencing of the FKRP, fukutin, POMGnT1, and POMT1 genes in all patients with abnormal alpha-dystroglycan immunofluorescence identified mutations in one patient for each of these genes and two patients had mutations in POMT2. Twelve percent of patients had abnormalities in collagen VI immunofluorescence, and we identified disease-causing COL6 mutations in eight of nine patients in whom the genes were sequenced. Laminin alpha2 deficiency accounted for only 8% of CMD. alpha7-Integrin staining was absent in 12 of 45 patients studied, and ITGA7 gene mutations were excluded in all of these patients. CONCLUSIONS: We define the distribution of different forms of congenital muscular dystrophy in a large cohort of mixed ethnicity and demonstrate the utility and limitations of current diagnostic techniques.
|Mild POMGnT1 mutations underlie a novel limb-girdle muscular dystrophy variant. |
Clement, EM; Godfrey, C; Tan, J; Brockington, M; Torelli, S; Feng, L; Brown, SC; Jimenez-Mallebrera, C; Sewry, CA; Longman, C; Mein, R; Abbs, S; Vajsar, J; Schachter, H; Muntoni, F
Archives of neurology 65 137-41 2008
Mutations in protein-O-mannose-beta1,2-N-acetylglucosaminyltransferase 1 (POMGnT1) have been found in muscle-eye-brain disease, a congenital muscular dystrophy with structural eye and brain defects and severe mental retardation.To investigate whether mutations in POMGnT1 could be responsible for milder allelic variants of muscular dystrophy.Screening for mutations in POMGnT1.Tertiary neuromuscular unit.A patient with limb-girdle muscular dystrophy phenotype, with onset at 12 years of age, severe myopia, normal intellect, and decreased alpha-dystroglycan immunolabeling in skeletal muscle.A homozygous POMGnT1 missense mutation (c.1666Ggreater than A, p.Asp556Asn) was identified. Enzyme studies of the patient's fibroblasts showed an altered kinetic profile, less marked than in patients with muscle-eye-brain disease and in keeping with the relatively mild phenotype in our patient.Our findings widen the spectrum of disorders known to result from mutations in POMGnT1 to include limb-girdle muscular dystrophy with no mental retardation. We propose that this condition be known as LGMD2M. The enzyme assay used to diagnose muscle-eye-brain disease may not detect subtle abnormalities of POMGnT1 function, and additional kinetic studies must be carried out in such cases.
|Mutations in contactin-1, a neural adhesion and neuromuscular junction protein, cause a familial form of lethal congenital myopathy. |
Alison G Compton,Douglas E Albrecht,Jane T Seto,Sandra T Cooper,Biljana Ilkovski,Kristi J Jones,Daniel Challis,David Mowat,Barbara Ranscht,Melanie Bahlo,Stanley C Froehner,Kathryn N North
American journal of human genetics 83 2008
We have previously reported a group of patients with congenital onset weakness associated with a deficiency of members of the syntrophin-alpha-dystrobrevin subcomplex and have demonstrated that loss of syntrophin and dystrobrevin from the sarcolemma of skeletal muscle can also be associated with denervation. Here, we have further studied four individuals from a consanguineous Egyptian family with a lethal congenital myopathy inherited in an autosomal-recessive fashion and characterized by a secondary loss of beta2-syntrophin and alpha-dystrobrevin from the muscle sarcolemma, central nervous system involvement, and fetal akinesia. We performed homozygosity mapping and candidate gene analysis and identified a mutation that segregates with disease within CNTN1, the gene encoding for the neural immunoglobulin family adhesion molecule, contactin-1. Contactin-1 transcripts were markedly decreased on gene-expression arrays of muscle from affected family members compared to controls. We demonstrate that contactin-1 is expressed at the neuromuscular junction (NMJ) in mice and man in addition to the previously documented expression in the central and peripheral nervous system. In patients with secondary dystroglycanopathies, we show that contactin-1 is abnormally localized to the sarcolemma instead of exclusively at the NMJ. The cntn1 null mouse presents with ataxia, progressive muscle weakness, and postnatal lethality, similar to the affected members in this family. We propose that loss of contactin-1 from the NMJ impairs communication or adhesion between nerve and muscle resulting in the severe myopathic phenotype. This disorder is part of the continuum in the clinical spectrum of congenital myopathies and congenital myasthenic syndromes.Artículo Texto completo
|Muscular dystrophy associated with alpha-dystroglycan deficiency in Sphynx and Devon Rex cats. |
Martin, PT; Shelton, GD; Dickinson, PJ; Sturges, BK; Xu, R; LeCouteur, RA; Guo, LT; Grahn, RA; Lo, HP; North, KN; Malik, R; Engvall, E; Lyons, LA
Neuromuscular disorders : NMD 18 942-52 2008
Recent studies have identified a number of forms of muscular dystrophy, termed dystroglycanopathies, which are associated with loss of natively glycosylated alpha-dystroglycan. Here we identify a new animal model for this class of disorders in Sphynx and Devon Rex cats. Affected cats displayed a slowly progressive myopathy with clinical and histologic hallmarks of muscular dystrophy including skeletal muscle weakness with no involvement of peripheral nerves or CNS. Skeletal muscles had myopathic features and reduced expression of alpha-dystroglycan, while beta-dystroglycan, sarcoglycans, and dystrophin were expressed at normal levels. In the Sphynx cat, analysis of laminin and lectin binding capacity demonstrated no loss in overall glycosylation or ligand binding for the alpha-dystroglycan protein, only a loss of protein expression. A reduction in laminin-alpha2 expression in the basal lamina surrounding skeletal myofibers was also observed. Sequence analysis of translated regions of the feline dystroglycan gene (DAG1) in affected cats did not identify a causative mutation, and levels of DAG1 mRNA determined by real-time QRT-PCR did not differ significantly from normal controls. Reduction in the levels of glycosylated alpha-dystroglycan by immunoblot was also identified in an affected Devon Rex cat. These data suggest that muscular dystrophy in Sphynx and Devon Rex cats results from a deficiency in alpha-dystroglycan protein expression, and as such may represent a new type of dystroglycanopathy where expression, but not glycosylation, is affected.
|Multipotential stem cells recapitulate human infantile hemangioma in immunodeficient mice. |
Khan, ZA; Boscolo, E; Picard, A; Psutka, S; Melero-Martin, JM; Bartch, TC; Mulliken, JB; Bischoff, J
The Journal of clinical investigation 118 2592-9 2008
Infantile hemangioma is a benign endothelial tumor composed of disorganized blood vessels. It exhibits a unique life cycle of rapid postnatal growth followed by slow regression to a fibrofatty residuum. Here, we have reported the isolation of multipotential stem cells from hemangioma tissue that give rise to hemangioma-like lesions in immunodeficient mice. Cells were isolated based on expression of the stem cell marker CD133 and expanded from single cells as clonal populations. The CD133-selected cells generated human blood vessels 7 days after implantation in immunodeficient mice. Cell retrieval experiments showed the cells could again form vessels when transplanted into secondary recipients. The human vessels expressed GLUT-1 and merosin, immunodiagnostic markers for infantile hemangioma. Two months after implantation, the number of blood vessels diminished and human adipocytes became evident. Lentiviral expression of GFP was used to confirm that the hemangioma-derived cells formed the blood vessels and adipocytes in the immunodeficient mice. Thus, when transplanted into immunodeficient mice, hemangioma-derived cells recapitulated the unique evolution of infantile hemangioma--the formation of blood vessels followed by involution to fatty tissue. In summary, this study identifies a stem cell as the cellular origin of infantile hemangioma and describes for what we believe is the first time an animal model for this common tumor of infancy.
|Biochemical and ultrastructural evidence of endoplasmic reticulum stress in LGMD2I. |
Chiara A Boito, Marina Fanin, Bruno F Gavassini, Giovanna Cenacchi, Corrado Angelini, Elena Pegoraro
Virchows Archiv : an international journal of pathology 451 1047-55 2007
Limb girdle muscular dystrophy type 2I (LGMD2I) is due to mutations in the fukutin-related protein gene (FKRP), encoding a putative glycosyltransferase involved in alpha-dystroglycan processing. To further characterize the molecular pathogenesis of LGMD2I, we conducted a histological, immunohistochemical, ultrastructural and molecular analysis of ten muscle biopsies from patients with molecularly diagnosed LGMD2I. Hypoglycosylation of alpha-dystroglycan was observed in all FKRP-mutated patients. Muscle histopathology was consistent with either severe muscular dystrophy or myopathy with a mild inflammatory response consisting of up-regulation of class I major histocompatibility complex in skeletal muscle fibers and small foci of mononuclear cells. At the ultrastructural level, muscle fibers showed focal thinning of basal lamina and swollen endoplasmic reticulum cisternae with membrane re-arrangement. The pathways of the unfolded protein response (UPR; glucose-regulated protein 78 and CHOP) were significantly activated in LGMD2I muscle tissue. Our data suggest that the UPR response is activated in LGMD2I muscle biopsies, and the observed histopathological and ultrastructural alterations may be related to sarcoplasmic structures involved in FKRP and alpha-dystroglycan metabolism and malfunctioning.
|Dystroglycan receptor is involved in integrin activation in intestinal epithelia. |
Driss, A; Charrier, L; Yan, Y; Nduati, V; Sitaraman, S; Merlin, D
American journal of physiology. Gastrointestinal and liver physiology 290 G1228-42 2006
The dystroglycans (alpha-DG and beta-DG), which play important roles in the formation of basement membranes, have been well studied in skeletal muscle and nerve, but their expression and localization in intestinal epithelial cells has not been previously investigated. Here, we demonstrated that the DG complex, composed of alpha-DG, beta-DG, and utrophin, is specifically expressed in the basolateral membrane of the Caco-2-BBE monolayer. The DG complex coprecipitated with beta(1)-integrin, suggesting a possible interaction among these proteins. In addition, we observed that activation of DG receptors by laminin-1 enhanced the interaction between beta(1)-integrin and laminin-1, whereas activation of DG receptors by laminin-2 reduced the interaction between beta(1)-integrin and laminin-2. Finally, we demonstrated that the intracellular COOH-terminal tail of beta-DG and its binding to the DG binding domain of utrophin are crucial for the interactions between laminin-1/-2 and beta(1)-integrin. Collectively, these novel results indicate that dystroglycans play important roles in the regulation of interactions between intestinal epithelial cells and the extracellular matrix.Artículo Texto completo
|Prenatal diagnosis in laminin alpha2 chain (merosin)-deficient congenital muscular dystrophy: a collective experience of five international centers. |
Mariz Vainzof, Pascale Richard, Ralf Herrmann, Cecilia Jimenez-Mallebrera, Beril Talim, Lydia U Yamamoto, Céline Ledeuil, Rachael Mein, Stephen Abbs, Martin Brockington, Norma B Romero, Mayana Zatz, Haluk Topaloglu, Thomas Voit, Caroline Sewry, Francesco Muntoni, Pascale Guicheney, Fernando M S Tomé
Neuromuscular disorders : NMD 15 588-94 2005
The congenital muscular dystrophies (CMD) are clinically and genetically heterogeneous. The merosin (laminin alpha2 chain) deficient form (MDC1A), is characterized clinically by neonatal hypotonia, delayed motor milestones and associated contractures. It is caused by deficiency in the basal lamina of muscle fibers of the alpha2 chain of laminins 2 and 4 (LAMA2 gene at 6q22-23). Laminin alpha2 chain is also expressed in fetal trophoblast, which provides a suitable tissue for prenatal diagnosis in families where the index case has total deficiency of the protein. This article reports the collective experience of five centers over the past 10 years in 114 prenatal diagnostic studies using either protein analysis of the chorionic villus (CV) of the trophoblast plus DNA molecular studies with markers flanking the 6q22-23 region and intragenic polymorphisms (n=58), or using only DNA (n=44) or only protein (n=12) approaches. Of the 102 fetuses studied by molecular genetics, 27 (26%) were predicted to be affected while 75 (74%) were considered as unaffected, with 52 (51%) being heterozygous, thus conforming closely to an autosomal recessive inheritance. In 18 of the 27 affected fetuses, the trophoblast was studied by immunocytochemistry and there was a total or only traces deficiency of the protein in CV basement membrane in all. In 10 cases material from the presumably affected fetus was available for analysis after termination of the pregnancy and immunohistochemical study confirmed the diagnosis in all of them. Prenatal studies of 'at risk' pregnancies in the five centers produced neither false negative (merosin-deficiency in CVs in a normal fetus), nor false positive (normal merosin expression in CVs and affected child), indicating the reliability of the technique, when all the necessary controls are done. Our experience suggests that protein and DNA analysis can be used either independently or combined, according to the facilities of each center, to provide accurate prenatal diagnosis of the MDC1A, and have an essential role in genetic counseling.
|Single section Western blot: improving the molecular diagnosis of the muscular dystrophies. |
Sandra T Cooper, Harriet P Lo, Kathryn N North
Neurology 61 93-7 2003
Single section Western blot (SSWB) is an improved methodology for molecular diagnosis of the muscular dystrophies, requiring only a single 8-microm muscle biopsy cryosection for the simultaneous analysis of multiple disease candidates. The authors demonstrate that SSWB can be used for diagnosis of dystrophinopathies, to identify haploinsufficiency in autosomal dominant laminopathy, and as a tool to distinguish between primary and secondary immunohistochemical abnormalities in limb-girdle muscular dystrophy type 2B.
|Mutations in the human LARGE gene cause MDC1D, a novel form of congenital muscular dystrophy with severe mental retardation and abnormal glycosylation of alpha-dystroglycan. |
Longman, C; Brockington, M; Torelli, S; Jimenez-Mallebrera, C; Kennedy, C; Khalil, N; Feng, L; Saran, RK; Voit, T; Merlini, L; Sewry, CA; Brown, SC; Muntoni, F
Human molecular genetics 12 2853-61 2003
The congenital muscular dystrophies (CMD) are a heterogeneous group of autosomal recessive disorders. A new pathomechanism has recently been identified in a group of these disorders in which known or putative glycosyltransferases are defective. Common to all these conditions is the hypoglycosylation of alpha-dystroglycan. Fukuyama CMD, muscle-eye-brain disease and Walker-Warburg syndrome, each associated with eye abnormalities and neuronal migration defects, result from mutations in fukutin, POMGnT1 and POMT1, respectively, while mutations in the fukutin-related protein (FKRP) gene cause congenital muscular dystrophy 1C, typically lacking brain involvement. Another putative glycosyltransferase, Large, is mutated in the myodystrophy mouse. The human homologue of this gene is therefore a strong candidate for involvement in novel forms of muscular dystrophy. We studied 36 patients with muscular dystrophy and either mental retardation, structural brain changes or abnormal alpha-dystroglycan immunolabelling, unlinked to any reported CMD loci. Linkage analysis in seven informative families excluded involvement of LARGE but sequencing of this gene in the remaining 29 families identified one patient with a G1525A (Glu509Lys) missense mutation and a 1 bp insertion, 1999insT. This 17-year-old girl presented with congenital muscular dystrophy, profound mental retardation, white matter changes and subtle structural abnormalities on brain MRI. Her skeletal muscle biopsy showed reduced immunolabelling of alpha-dystroglycan. Immunoblotting with an antibody to a glycosylated epitope demonstrated a reduced molecular weight form of alpha-dystroglycan that retained some laminin binding activity. This is the first description of mutations in the human LARGE gene and we propose to name this new disorder MDC1D.
|Novel mutations in collagen VI genes: expansion of the Bethlem myopathy phenotype. |
P C Scacheri, E M Gillanders, S H Subramony, V Vedanarayanan, C A Crowe, N Thakore, M Bingler, E P Hoffman
Neurology 58 593-602 2002
OBJECTIVE: To investigate the molecular basis of autosomal dominant limb-girdle muscular dystrophy (AD-LGMD) in three large new families. METHODS AND RESULTS: Genome-wide linkage was performed to show that the causative gene in all three families localized to chromosome 21q22.3 (Zmax = 10.3; theta = 0). This region contained the collagen VI alpha1 and alpha2 genes, which have been previously shown to harbor mutations causing a relatively mild congenital myopathy with contractures (Bethlem myopathy). Screening of the collagen VI alpha1 and alpha2 genes revealed novel, causative mutations in each family (COL6A1-K121R, G341D; COL6A2-D620N); two of these mutations were in novel regions of the proteins not previously associated with disease. Collagen VI is a ubiquitously expressed component of connective tissue; however, both limb-girdle muscular dystrophy and Bethlem myopathy patients show symptoms restricted to skeletal muscle. To address the muscle-specific symptoms resulting from collagen VI mutations, the authors studied three patient muscle biopsies at the molecular level (protein expression). A marked reduction of laminin beta1 protein in the myofiber basal lamina in all biopsies was found, although this protein was expressed normally in the neighboring capillary basal laminae. CONCLUSIONS: The authors' studies widen the clinical spectrum of Bethlem myopathy and suggest collagen VI etiology should be investigated in dominant limb-girdle muscular dystrophy. The authors hypothesize that collagen VI mutations lead to muscle-specific defects of the basal lamina, and may explain the muscle-specific symptoms of Bethlem and limb-girdle muscular dystrophy patients with collagen VI mutations.
|Deleted in colorectal carcinoma and differentially expressed integrins mediate the directional migration of neural precursors in the rostral migratory stream. |
Shin-ichi Murase, Alan F Horwitz
The Journal of neuroscience : the official journal of the Society for Neuroscience 22 3568-79 2002
Precursors of the olfactory interneurons migrate from the subventricular zone via the rostral migratory stream (RMS). To investigate the molecular mechanisms by which RMS cells migrate, we used a slice preparation, which allows the migrating cells to be imaged at very high temporal and spatial resolution in the presence of added inhibitors. Using immunohistochemistry, we first determined that the alpha1-, beta8-, and beta1-integrin subunits and the alpha5- and gamma1-laminin subunits are expressed during embryonic day 16 to the early postnatal stage. During early postnatal days, alpha(v)- and beta6-integrins appeared, and their expression persisted throughout adulthood. The migrating cells also expressed the netrin receptors neogenin and Deleted in Colorectal Carcinoma (DCC). Netrin-1 is expressed in olfactory mitral cells. Anti-integrin antibodies inhibited the production of protrusions as well as cellular translocation. In contrast, anti-DCC antibodies primarily altered the direction of the protrusions; consequently, the migration was no longer unidirectional, and the speed was reduced. Thus, the interaction of DCC, possibly through an interaction with netrin-1, contributes to the direction of migration by regulating the formation of directed protrusions. In contrast, the integrins function in production of protrusions and cellular translocation, with different integrins participating at different developmental stages.
|Severe progressive form of congenital muscular dystrophy with calf pseudohypertrophy, macroglossia and respiratory insufficiency. |
Susana Quijano-Roy, Lucía Galan, Ana Ferreiro, Fawzia Cheliout-Héraut, Françoise Gray, Michel Fardeau, Annie Barois, Pascale Guicheney, Norma B Romero, Brigitte Estournet
Neuromuscular disorders : NMD 12 466-75 2002
A novel form of congenital muscular dystrophy in four unrelated patients is proposed. Congenital hypotonia, markedly increased CK, calf pseudohypertrophy and proximal weakness were common early findings. Two cases were severely affected since infancy and never walked. The phenotypical homogeneity was not very evident until advanced stages of the disease. All the patients showed catastrophic progression of the weakness, severe restrictive respiratory insufficiency, macroglossia, peculiar extreme amyotrophy of hands and feet, and a round and 'puffy' face. All patients became tetraplegic and required mechanical ventilation. Two cases had signs of mild cardiac involvement. The only non-tracheotomised patient died of respiratory complications. No mental retardation or specific brain abnormalities were observed. All patients showed secondary deficit of laminin 2 and up-regulation of laminin 5 in muscle. Expression of -dystroglycan was severely reduced in two available muscle samples. The known loci for congenital muscular dystrophies were excluded in the only consanguineous case by linkage analysis. Clinical, immunohistochemical and genetic findings strongly suggest a distinct entity.
|X-linked myopathy with excessive autophagy: a clinicopathological study of five new families. |
B Chabrol, D Figarella-Branger, M Coquet, J Mancini, D Fontan, J M Pedespan, C Francannet, J Pouget, A M Beaufrère, J F Pellissier, B Chabrol, D Figarella-Branger, M Coquet, J Mancini, D Fontan, J M Pedespan, C Francannet, J Pouget, A M Beaufrère, J F Pellissier
Neuromuscular disorders : NMD 11 376-88 2001
In 1988, Kalimo et al. (Ann Neurol 23 (1988) 258)described a new type of X-linked myopathy in a Finnish family. The clinical course was characterized by slow progression of muscle weakness without loss of ambulation in childhood and no evidence of cardiac, respiratory, or central nervous system involvement. Muscle fibers were not necrotic and showed excessive autophagic activity and exocytosis of the phagocytosed material. These authors proposed the name X-linked myopathy with excessive autophagy. Subsequently, only one French family has been reported with similar clinical and histopathological data. We report here five new families with a total of eight affected boys with the same clinical and histopathological features as reported in the original families. Histopathological findings of an asymptomatic mother are also reported. Vacuolar changes in muscle fibers result both from invaginations of the sarcolemma along with a variable component of basal lamina and from an autophagic process. The complement C5b-9 membrane attack complex associated with MHC class 1 antigen and calcium deposits is involved in muscle fiber damage. Among the X-linked myopathies, the identification of this new type is of great interest because of its favorable prognosis and unique morphological findings.
|Calpain 3 gene mutations: genetic and clinico-pathologic findings in limb-girdle muscular dystrophy. |
J Chae, N Minami, Y Jin, M Nakagawa, K Murayama, F Igarashi, I Nonaka
Neuromuscular disorders : NMD 11 547-55 2001
Mutations in the calpain 3 gene have been proven to be responsible for limb-girdle muscular dystrophy (LGMD) type 2A. To determine the incidence and genotypes of the calpain 3 (p94) gene mutations in Japanese LGMD patients, we sequenced the gene in 80 patients with clinical characteristics of autosomal recessive or sporadic LGMD. We identified 13 distinct pathogenic mutations in 21 patients (26%), including seven missense mutations, four splice-site mutations and two insertions in which six were novel mutations. Among the 21 patients, 15 (71%) had three types of the common missense (G233V, R461C, D707G) and one insertion (1795-1796insA) mutation. The patients had slowly progressive muscle weakness with age of onset of the disease varying from 6 to 52 years, averaging 20.9. The most striking pathologic findings were the presence of lobulated fibers in 14 patients, especially in the advanced stages. Differing from Duchenne and Becker muscular dystrophy, opaque (hypercontracted) fibers were very rarely seen. These findings may be helpful in establishing diagnostic screening strategies in Japanese LGMD patients.
|The expanding phenotype of laminin alpha2 chain (merosin) abnormalities: case series and review. |
K J Jones, G Morgan, H Johnston, V Tobias, R A Ouvrier, I Wilkinson, K N North
Journal of medical genetics 38 649-57 2001
Initial reports of patients with laminin alpha2 chain (merosin) deficiency had a relatively homogeneous phenotype, with classical congenital muscular dystrophy (CMD) characterised by severe muscle weakness, inability to achieve independent ambulation, markedly raised creatine kinase, and characteristic white matter hypodensity on cerebral magnetic resonance imaging. We report a series of five patients with laminin alpha2 deficiency, only one of whom has this severe classical CMD phenotype, and review published reports to characterise the expanded phenotype of laminin alpha2 deficiency, as illustrated by this case series. While classical congenital muscular dystrophy with white matter abnormality is the commonest phenotype associated with laminin alpha2 deficiency, 12% of reported cases have later onset, slowly progressive weakness more accurately designated limb-girdle muscular dystrophy. In addition, the following clinical features are reported with increased frequency: mental retardation (~6%), seizures (~8%), subclinical cardiac involvement (3-35%), and neuronal migration defects (4%). At least 25% of patients achieve independent ambulation. Notably, three patients with laminin alpha2 deficiency were asymptomatic, 10 patients had normal MRI (four with LAMA2 mutations reported), and between 10-20% of cases had maximum recorded creatine kinase of less than 1000 U/l. LAMA2 mutations have been identified in 25% of cases. Sixty eight percent of these have the classical congenital muscular dystrophy, but this figure is likely to be affected by ascertainment bias. We conclude that all dystrophic muscle biopsies, regardless of clinical phenotype, should be studied with antibodies to laminin alpha2. In addition, the use of multiple antibodies to different regions of laminin alpha2 may increase the diagnostic yield and provide some correlation with severity of clinical phenotype.Artículo Texto completo
|Muscle membrane-skeleton protein changes and histopathological characterization of muscle-eye-brain disease. |
M Auranen, J Rapola, H Pihko, M Haltia, I Leivo, S Soinila, I Virtanen, H Kalimo, L V Anderson, P Santavuori, H Somer
Neuromuscular disorders : NMD 10 16-23 2000
Muscle-eye-brain disease belongs to congenital muscular dystrophies with central nervous system abnormalities. The etiology of MEB is still unknown, but abnormal immunoreactivity for laminin-2 has been reported. To evaluate disease progression in muscle tissue, 32 biopsy specimens from 17 muscle-eye-brain patients were analysed. The samples of four patients were studied by immunohistochemical techniques and by quantitative Western blotting. The samples showed a great variation in the muscle pathology. Regenerative fibers and mild fiber size variation were present in over 60%. At infancy, necrotic and regenerative fibers were common, while fat infiltration was the most prominent finding in the age group over five years. In quantitative studies, the amount of laminin alpha 2 chain was clearly reduced to 10-20% of normal. In contrast, laminin beta 2 chain was overexpressed in the Western blotting studies. These findings may reflect a yet unidentified primary disturbance in the basement membrane composition and function.
|Oculopharyngeal muscular dystrophy in a Japanese family with a short GCG expansion (GCG)(11) in PABP2 gene. |
T Nagashima, H Kato, M Kase, S Maguchi, Y Mizutani, K Matsuda, T Chuma, Y Mano, Y Goto, N Minami, I Nonaka, K Nagashima
Neuromuscular disorders : NMD 10 173-7 2000
Clinicopathological and molecular genetic findings on a new Japanese family with oculopharyngeal muscular dystrophy are reported. The family has 54 members, ten of whom are affected (seven male and three female), in 3 generations. Three affected males, one affected female and one unaffected female of seven living siblings in the third generation were examined. Bilateral ptosis developed in the 4th and 5th decades in the three male cases, and in the 7th decade in the female, and this was followed by diplopia, nasal voice, dysphagia and muscle weakness. In addition, severe external ophthalmoplegia, dysphonia, and proximal amyotrophy were prominent in this family. Electromyographs revealed myogenic/neurogenic changes, and computed tomography disclosed selective muscle wasting with fatty replacement, predominantly in the lower extremities. Muscle biopsy in the four affected patients showed variation in fiber size, and the presence of small angulated fibers and occasional rimmed vacuoles. Electron microscopic examination revealed an accumulation of filamentous inclusions in muscle fiber nuclei. DNA analysis identified that (GCG)(6) in the PABP2 gene was expanded to (GCG)(11) in the four affected cases examined. All studies were negative in the one unaffected. These results confirm that OPMD is caused by GCG short expansion and provides insights into the genetic mechanisms which may contribute to adult onset myopathy, confined to oculopharyngeal muscles.
|Multiplex Western blotting system for the analysis of muscular dystrophy proteins |
Anderson, L V and Davison, K
Am J Pathol, 154:1017-22 (1999) 1999
|Merosin-positive congenital muscular dystrophy with transient brain dysmyelination, pontocerebellar hypoplasia and mental retardation. |
T Voit, R D Cohn, J Sperner, B Leube, L Sorokin, T Toda, R Herrmann
Neuromuscular disorders : NMD 9 95-101 1999
The congenital muscular dystrophies (CMDs) are a heterogeneous group of disorders. Among these, the laminin alpha 2 chain 'merosin' deficient CMD is caused by mutations of the LAMA2 gene on chr 6q2 and Fukuyama CMD is linked to chr 9q31. We report a 7-year-old boy who was born to consanguineous healthy parents. His motor and mental development were slow. Creatine kinase (CK) was elevated (2.100 U/l), and the muscle biopsy was dystrophic. He sat unsupported at 12 months and took his first steps at 3 years of age. At 6 years of age he could walk up to 500 m. He was mentally retarded and spoke single words only. At 1 year, MR imaging of the brain showed abnormal increased periventricular T2-signal, consistent with dysmyelination as well as pontocerebellar hypoplasia and several cerebellar cysts. The pattern of gyration was normal. Follow-up at 4 years showed normalization of the previously abnormal periventricular T2-signal. Immunohistochemical analysis of the skeletal muscle showed normal expression of laminin alpha 2 for a C-terminal antibody and antibodies to the 300 and 150 kDa fragments, as well as of laminins alpha 5, beta 1, beta 2 and gamma 1. The boy has two healthy younger brothers. Linkage analysis excluded the candidate loci on chromosomes 6q2 and 9q31. As such, the patient's data are suggestive of a new form of laminin alpha 2 positive CMD characterized by transient brain dysmyelination, pontocerebellar hypoplasia and mental retardation.
|Changes in the cytoskeletal proteins, sarcoplasmic reticulum, and capillaries in acute relaxant-steroid myopathy (ARSM) in contrast to the corticosteroid myopathy. |
S Matsubara, T Kitaguchi, E Isozaki, K Miyamoto, S Hirai, S Matsubara, T Kitaguchi, E Isozaki, K Miyamoto, S Hirai
Acta neuropathologica 97 515-9 1999
Since we reported a case of acute relaxant-steroid myopathy (ARSM) in 1994, we continued histological studies and compared the findings with those in a case of corticosteroid myopathy (CM). It was revealed that (1) dystrophin, spectrin, beta dystroglycan, and sarcoglycans on the cell surface were decreased, (2) regular arrangement of the sarcoplasmic reticulum was lost, and (3) some capillaries were degenerated. Since none of these changes were seen in CM, it became clear that ARSM is different from CM. It was estimated that continuous administration of non-depolarizing muscle relaxant produces a state akin to denervation. Combination of denervation, immobilization and circulatory disturbance in ARSM not only augments the effects of corticosteroids, but they produce changes different from CM, namely impairment of the cell membrane system (both internal and external) and capillary degeneration.
|Early onset autosomal dominant myopathy with rigidity of the spine: a possible role for laminin beta 1? |
Taylor, J, et al.
Neuromuscul. Disord., 7: 211-6 (1997) 1997
We describe 17 individuals from seven families with a slowly progressive, early onset, autosomal dominant myopathy with proximal muscle weakness, calf hypertrophy, contractures, spinal rigidity and, in five of the adult cases, a cardiac conduction defect. A deficiency of the laminin beta 1 chain of the skeletal muscle fibres was found in the older individuals of these families, but not the younger members. Other laminin chains, dystrophin and the dystrophin-associated glycoproteins were normal. The age-related deficiency of the laminin beta 1 is restricted to the skeletal muscle fibres and not the vascular tissue, suggesting that this may be a secondary phenomenon. These findings suggest that a laminin or a laminin-binding protein is implicated in some forms of dominant limb girdle myopathies.
|Immunohistochemical study of merosin-negative congenital muscular dystrophy: laminin alpha 2 deficiency in skin biopsy. |
Marbini, A, et al.
Acta Neuropathol., 94: 103-8 (1997) 1997
We studied the immunohistochemical expression of laminin subunits alpha 2, alpha 1, beta 1 in muscle and skin biopsy samples from three patients with congenital muscular dystrophy (CMD), and from ten control patients investigated for various neuromuscular disorders. Merosin alpha 2 chain was not detectable in the basement membrane of muscle fibers, or in the nerve endings, cutaneous nerves, and corium in the skin of the CMD patients, whereas it was clearly expressed in the skin biopsy samples from control patients, especially in the nerve endings of the arrector pili muscles. Laminin alpha 1 chain was expressed in the corium, in the muscle fiber membranes of arrector pili muscles and in cutaneous nerve fibers, perineurium and blood vessels in controls and in CMD patients. Laminin beta 1 chain was faintly expressed in the corium, and a diffuse labeling was detected on arrector pili muscle with enhanced expression at nerve endings, intracutaneous nerves and capillaries, with similar findings in all biopsy specimens. For merosin-negative CMD patients, skin biopsy may provide a diagnostic alternative to muscle biopsy since merosin deficiency can be demonstrated in the skin neural structures, and in particular in the nerve endings of the arrector pili smooth muscles.
|Refinement of the laminin alpha2 chain locus to human chromosome 6q2 in severe and mild merosin deficient congenital muscular dystrophy. |
Naom, I S, et al.
J. Med. Genet., 34: 99-104 (1997) 1997
About half of the children with classical congenital muscular dystrophy (CMD) show an absence in their skeletal muscle of laminin alpha2 chain, one of the components of the extracellular matrix protein, merosin. Linkage analysis implicated the laminin alpha2 chain gene (LAMA2) on chromosome 6q2, now confirmed by the discovery of mutations in the laminin alpha2 chain gene. We have further investigated the location of the LAMA2 locus on chromosome 6q2, using both linkage analysis in nine informative families and homozygosity mapping in 13 consanguineous families. Four of these families only had mild or moderate down regulation of laminin alpha2 chain expression and a milder phenotype; the rest had no protein or only a trace. Haplotype analysis in all the informative families, including those with partial laminin alpha2 expression, was compatible with linkage to chromosome 6q2. This observation expands the spectrum of the phenotype secondary to laminin alpha2 chain deficiency. Our results suggest that the LAMA2 locus is more centromeric than previously proposed. Recombinant events place the locus between markers D6S470 and D6S1620 in an interval of less than 3 cM.
|Late onset muscular dystrophy with cerebral white matter changes due to partial merosin deficiency. |
Tan, E, et al.
Neuromuscul. Disord., 7: 85-9 (1997) 1997
Merosin-deficient congenital muscular dystrophy (CMD) is an autosomal recessive condition usually with onset at birth or within the first months of life. Affected children are severely disabled and usually do not achieve the ability to walk without support. They invariably have white matter abnormalities on brain magnetic resonance imaging (MRI). We report a 29-year-old man with a late childhood onset limb-girdle type muscular dystrophy and cerebral white matter changes on MRI. Immunocyto-chemical studies of the patient's muscle biopsy showed a reduction in expression of the laminin alpha 2 chain of merosin. The patient had three affected siblings, and microsatellite genotyping confirmed linkage to the laminin alpha 2 locus (LAMA2) on chromosome 6q2 in this family. This case probably represents a milder allelic variant of classical merosin-deficient CMD. Merosin status should be assessed in patients with late-onset limb girdle muscular dystrophy.
|Abnormal expression of laminin beta 1 chain in skeletal muscle of adult-onset limb-girdle muscular dystrophy. |
M Li, D W Dickson, A J Spiro, M Li, D W Dickson, A J Spiro
Archives of neurology 54 1457-61 1997
BACKGROUND: Laminin 2 is a major component of the basal lamina of skeletal muscle cells. It is a heterotrimer composed of 3 chains: merosin (laminin alpha 2 chain), beta 1, and gamma 1. Deficiency of merosin, with or without laminin beta 1 chain reduction, is associated with some forms of congenital muscular dystrophy. Deficient expression of laminin beta 1 chain is also associated with some cases of merosin-positive congenital muscular dystrophy. The expression of laminin 2 subunits has not been well studied in the skeletal muscle of limb-girdle muscular dystrophy (LGMD), nor has much attention been given to the significance of reduction of individual laminin 2 subunits, such as beta 1. OBJECTIVES: To examine the expression of laminin 2 subunits in skeletal muscle in patients with LGMD and to define the clinical features of patients with LGMD who have abnormal expression of laminin 2 subunits. METHODS: We studied muscle biopsy specimens from 18 patients with LGMD using immunofluorescence with antibodies against dystrophin C-terminus, beta-dystroglycan, alpha-sarcoglycan, gamma-sarcoglycan, and the laminin subunits merosin, beta 1, and gamma 1. Of the 18 biopsy specimens, 9 were available for electron microscopic examination of the muscle basement membrane. The clinical features associated with abnormal laminin beta 1 chain immunoreactivity were further described. RESULTS: Laminin beta 1 chain was either barely detectable or severely reduced in 3 cases of patients with LGMD in which the biopsy specimens showed normal staining with the other antibodies. Patients in all 3 cases had common clinical features consistent with a slowly progressive, adult-onset LGMD. Specimens from 2 of the 3 cases that were available for ultrastructural examination showed significant abnormalities of the muscle fiber basement membrane. CONCLUSIONS: Abnormal expression of laminin beta 1 chain without concomitant deficiency of alpha-sarcoglycan in skeletal muscle has not been previously described in LGMD. Reduced laminin beta 1 chain immunoreactivity may potentially serve as a marker for defining subsets of individuals with LGMD, in particular those with slowly progressive, adult-onset pelvifemoral presentation. The abnormality of muscle fiber basement membranes in specimens from cases that were available for ultrastructural study suggests that defects in the extracellular matrix may play a role in the pathogenesis of this subset of LGMD.
|Disruption of muscle basal lamina in congenital muscular dystrophy with merosin deficiency. |
C Minetti, M Bado, G Morreale, M Pedemonte, G Cordone
Neurology 46 1354-8 1996
We studied three new cases of congenital muscular dystrophy (CMD) with homogeneous clinical and laboratory features, represented by congenital muscle hypotonia and weakness, early contractures, elevated serum CK, and dystrophic pattern at muscle biopsy, without clinical impairment of CNS. Merosin, the laminin isoform that contains the alpha 2 heavy chain, was absent in muscle fibers of all the patients by immunohistochemistry and by immunoblot. By electron microscopy, we found a severe disruption of muscle fiber basal lamina, but not of blood vessel basal lamina, which contains the laminin alpha 1 heavy chain isoform. This disruption may play a key role in the degeneration of muscle fibers and in the abnormal proliferation of connective tissue seen in CMD.
|Characterization of delta-sarcoglycan, a novel component of the oligomeric sarcoglycan complex involved in limb-girdle muscular dystrophy. |
D Jung, F Duclos, B Apostol, V Straub, J C Lee, V Allamand, D P Venzke, Y Sunada, C R Moomaw, C J Leveille, C A Slaughter, T O Crawford, J D McPherson, K P Campbell
The Journal of biological chemistry 271 32321-9 1996
The sarcoglycan complex is known to be involved in limb-girdle muscular dystrophy (LGMD) and is composed of at least three proteins: alpha-, beta-, and gamma-sarcoglycan. delta-Sarcoglycan has now been identified as a second 35-kDa sarcolemmal transmembrane glycoprotein that shares high homology with gamma-sarcoglycan and is expressed mainly in skeletal and cardiac muscle. Biochemical analysis has demonstrated that gamma- and delta-sarcoglycan are separate entities within the sarcoglycan complex and that all four sarcoglycans exist in the complex on a stoichiometrically equal basis. Immunohistochemical analysis of skeletal muscle biopsies from patients with LGMD2C, LGMD2D, and LGMD2E demonstrated a reduction of the entire sarcoglycan complex in these muscular dystrophies. Furthermore, we have mapped the human delta-sarcoglycan gene to chromosome 5q33-q34 in a region overlapping the recently linked autosomal recessive LGMD2F locus.
|Increased laminin A expression in regenerating myofibers in neuromuscular disorders. |
Mundegar, R R, et al.
Muscle Nerve, 18: 992-9 (1995) 1995
Laminin is a basement membrane (BM) glycoprotein composed of three of five subunits, the A, M, B1, B2, and the S chain. Four forms of laminin, A-B1-B2, A-S-B2, M-B1-B2, and M-S-B2, have been identified. Laminin is implicated in various biological processes such as cell adhesion and differentiation. We studied immunohistochemically the expression of the four laminin subunits A, M, B1, B2 as well as of neural cell adhesion molecule (N-CAM, CD56), a marker of regenerating myofibers, in various neuromuscular disorders. In normal muscle, the predominant subunits of myofiber laminin were M, B1, and B2. The A chain was only faintly expressed in myofiber BM. In inflammatory myopathies and dystrophinopathies myofiber laminin A expression was greatly increased. An average of 80% and 63% of laminin A-positive myofibers in inflammatory myopathies and dystrophinopathies, respectively, were additionally CD56 positive. Laminin A and CD56 expression in denervating diseases and mitochondrial myopathies were negligible. Expression of M, B1, and B2 subunits did not seem to be altered in the diseased conditions examined above. The data suggest that laminin A is upregulated in inflammatory myopathies and dystrophinopathies and, most markedly in regenerating myofibers.
|Merosin, a protein specific for basement membranes of Schwann cells, striated muscle, and trophoblast, is expressed late in nerve and muscle development. |
Leivo, I and Engvall, E
Proc. Natl. Acad. Sci. U.S.A., 85: 1544-8 (1988) 1988
We have identified a tissue-specific basement membrane-associated protein by using monoclonal antibodies prepared against a protein fraction of human placenta. In immunofluorescence, the monoclonal antibodies stained basement membranes of Schwann cells, striated muscle, and trophoblast, whereas no reaction was seen with any other basement membrane or tissue structure. In antibody-affinity chromatography of proteolytic digests of human placenta, a 65-kDa polypeptide was bound by these monoclonal antibodies. Rabbit antisera and monoclonal antibodies raised against the isolated 65-kDa polypeptide stained human and monkey tissues identically to the original monoclonal antibodies and reacted with an 80-kDa polypeptide in tissue extracts prepared without proteolysis. The 65-kDa and 80-kDa polypeptides were shown to be immunologically distinct from laminin, type IV collagen, fibronectin, and major serum proteins. They presumably represent a novel basement membrane-associated protein, which we have named merosin. No merosin immunoreactivity could be detected in cultures of any of 28 established cell lines. In developing mouse tissues, merosin staining first appeared at the newborn stage. The restricted tissue distribution and late developmental appearance of merosin suggest that the protein has a tissue-specific function associated with a high level of differentiation.
|Enzyme immunoassay ELISA and EMIT. |
Meth. Enzymol., 70: 419-39 (1980) 1980
|Anti-Laminin alpha2, clone 5H2 - Data Sheet|