Cytochemical studies of lectin binding by diseased human muscle

Lectin-binding characterizes the healthy human skeletal muscle glycophenotype and identifies disease-specific changes in dystrophic muscle

Our understanding of muscle glycosylation to date has derived from studies in mouse models and a limited number of human lectin histochemistry studies. As various therapeutic approaches aimed at treating patients with muscular dystrophies are being translated from rodent models to human, it is critical to better understand human muscle glycosylation and relevant disease-specific differences between healthy and dystrophic muscle. Here, we report the first quantitative characterization of human muscle glycosylation, and identify differentiation- and disease-specific differences in human muscle glycosylation. Utilizing a panel of 13 lectins with varying glycan specificities, we surveyed lectin binding to primary and immortalized myoblasts and myotubes from healthy and dystrophic sources. Following differentiation of primary and immortalized healthy human muscle cells, we observed increased binding of Narcissus pseudonarcissus agglutinin (NPA), PNA, MAA-II and WFA to myotubes compared to myoblasts. Following differentiation of immortalized healthy and dystrophic human muscle cells, we observed disease-specific differences in binding of NPA, Jac and Tricosanthes japonica agglutinin-I (TJA-I) to differentiated myotubes. We also observed differentiation- and disease-specific differences in binding of NPA, Jac, PNA, TJA-I and WFA to glycoprotein receptors in muscle cells. Additionally, Jac, PNA and WFA precipitated functionally glycosylated α-DG, that bound laminin, while NPA and TJA-I did not. Lectin histochemistry of healthy and dystrophic human muscle sections identified disease-specific differences in binding of O-glycan and sialic acid-specific lectins between healthy and dystrophic muscle. These results indicate that specific and discrete changes in glycosylation occur following differentiation, and identify specific lectins as potential biomarkers sensitive to changes in healthy human muscle glycosylation.

Quantitative evaluation of the beneficial effects in the mdx mouse of epigallocatechin gallate, an antioxidant polyphenol from green tea

In two separate previous studies, we reported that subcutaneous (sc) or oral administration of (−)-epigallocatechin-3-gallate (EGCG) limited the development of muscle degeneration of mdx mice, a mild phenotype model for Duchenne muscular dystrophy (DMD). However, it was not possible to conclude which was the more efficient route of EGCG administration because different strains of mdx mice, periods of treatment and methods of assessment were used. In this study, we investigated which administration routes and dosages of EGCG are the most effective for limiting the onset of dystrophic lesions in the same strain of mdx mice and applying the same methods of assessment. Three-week-old mdx mice were injected sc for 5 weeks with either saline or a daily average of 3 or 6 mg/kg EGCG. For comparison, age-matched mdx mice were fed for 5 weeks with either a diet containing 0.1% EGCG or a control diet. The effects of EGCG were assessed quantitatively by determining the activities of serum muscle-derived creatine kinase, isometric contractions of triceps surae muscles, integrated spontaneous locomotor activities, and oxidative stress and fibrosis in selected muscles. Oral administration of 180 mg/kg/day EGCG in the diet was found the most effective for significantly improving several parameters associated with muscular dystrophy. However, the improvements were slightly less than those observed previously for sc injection started immediately after birth. The efficacy of EGCG for limiting the development of dystrophic muscle lesions in mice suggests that EGCG may be of benefit for DMD patients.

A study of glycoconjugates in nasopharyngeal carcinoma with correlation to clinical transformation

Little is known about the glycoconjugate changes in human nasopharyngeal epithelium following neoplastic changes. Glycoconjugate histochemistry (Glycine maximus (SBA), Griffonia simplicifolia II (GSA-II), Ulex europaeus (UEA-I), Arachis hypogaea (PNA) and Canavalia ensiformis (ConA)) were performed on the following nasopharyngeal biopsies: 10 adenoid tissues (benign controls), 10 chronic inflammation, 20 squamous metaplasia, 20 undifferentiated carcinoma and 5 squamous cell carcinoma. These results were correlated with the clinical transformations findings. Strong ConA and PNA staining (after neuraminidase treatment (NA)) characterized a subpopulation of squamous metaplasia subjects who later transformed to nasopharyngeal carcinoma. Strong ConA and PNA (before and after NA) depicted the majority of undifferentiated carcinoma subjects having local recurrence following irradiation therapy. In squamous metaplasia, ConA and PNA (after NA) staining may serve as a warning sign for neoplastic changes. Strong stainings for ConA and PNA (before and after NA) in undifferentiated carcinoma subjects may predict a risk for local recurrence.

The complex-type oligosaccharide binding lectin Datura stramonium agglutinin detects type II A muscle fibres in the branchial biceps from man and cat

Complex-type oligosaccharides were detected in the sarcoplasm of muscle fibres from cat and human biceps using lectins and anticarbohydrate antibodies. The lectin Datura stramonium agglutinin strongly stained type II A fibres as identified by myosin ATPase activity after alkaline and acid preincubation. In contrast, all muscle fibres showed a moderate coarse granular staining after incubation with Tetracarpidum conophorum agglutinin and Telfairia occidentalis agglutinin which recognize tri-antennary complex glycans poorly bound by D. stramonium agglutinin. Strong sarcoplasmic staining in all muscle fibres was obtained after incubation with an antibody against branched N-acetyllactosamine structure while an antibody against binary 2 --> 3 sialyllactosamine glycans failed to detect the muscle fibres. Treatment of the muscle sections with sialidase prior to incubation with D. stramonium agglutinin did not influence the lectin staining pattern. Staining of blots from electrophoretically separated muscle proteins obtained by homogenization, solubilization and centrifugation of small muscle pieces showed D. stramonium agglutinin binding to a number of bands ranging from 200 kDa to 30 kDa. No D. stramonium agglutinin positive bands were observed in blots from separated mitochondrial proteins while blots from sarcoplasmic reticulum separated by electrophoresis stained many bands in the range from 200 kDa to 30 kDa. It may be concluded that all muscle fibres in human and cat biceps hold intracellular non-sialylated complex-type oligosaccharides and further, that a specific tri-antennary complex-type glycoform is strongly expressed in type II A fibres as recognized by D. stramonium agglutinin. These results indicate a different glycosylation of certain myofibrillar-associated proteins in muscle fibre types.

Lectin binding in skeletal muscle. Evaluation of alkaline phosphatase conjugated avidin staining procedures

Cryostat sections from rat gracilis muscles were incubated with different biotinylated lectins: Con A (Concanavilin A), WGA (Wheat germ agglutinin), SBA (soybean agglutinin), GS I and GS II (Griffonia simplicifolia agglutinin), LCA (Lens culinaris agglutinin), PNA (peanut agglutinin) and PSA (Pisum sativum agglutinin). The sections were subsequently treated with alkaline phosphatase conjugated avidin. The lectin binding sites were visualized after incubation in substrate media containing: (1) 5-bromo-4-chloro indoxyl phosphate and Nitro Blue tetrazolium or copper sulphate; (2) naphthol AS-MX phosphate or naphthol AS-BI phosphate and various types of diazonium salts; (3) alpha-naphthylphosphate and Fast Blue BB; (4) beta-glycerophosphate according to the method of Gomori. The results obtained with the alkaline phosphatase methods were compared with those seen with a streptavidin-horseradish peroxidase procedure. Several chromogen protocols for visualizing alkaline phosphatase activity showed differences in the ability to detect lectin binding sites. A sarcoplasmic reaction was evident for Con A, GS II, WGA, LCA, and PSA after incubation in the indoxyl phosphate medium. Sarcoplasmic reaction for GS II was also noticed after incubation with naphthol AS-MX Fast Blue BB and beta-glycerophosphate. The latter substrate also gave rise to a sarcoplasmic Con A reaction. With the indoxylphosphate tetrazolium salt method some muscle fibres showed a very strong intracellular reaction after incubation with Con A and GS II while the staining intensity was weak in other fibres. The same muscle fibres were stained with PAS. No sarcoplasmic reactions were observed with either naphthol phosphate media or with the diaminobenzidine peroxidase methods. Further, the staining of the muscle fibre periphery, connective tissue, an capillaries was intensified using the indoxyl method. The indoxylphosphate-tetrazolium salt method seems to be suitable for future investigations of lectin binding sites in muscle sections.

Lectin binding and desmin expression during necrosis, regeneration, and neurogenic atrophy of human skeletal muscle

Changes in the cytoplasm of skeletal muscle fibres during necrosis, regeneration, and neurogenic atrophy have been studied in a wide range of human neuromuscular diseases with a panel of eleven biotinylated lectins and by immunohistochemical staining for the cytoskeletal protein desmin. Increased binding of several lectins was observed in both necrotic and regenerating fibres, with Concanavalin A the most consistently positive lectin. Staining for desmin was strong in the cytoplasm of regenerating and partially damaged fibres and was lost in necrotic fibres, although there were differences in the staining reactions of the two antidesmin antibodies used. In fibres which had undergone neurogenic atrophy, cytoplasmic lectin binding was seen only with Griffonia simplicifolia 1 lectin, and desmin was expressed more strongly than in normal fibres. Lectin binding and immunohistochemical staining from desmin can supplement the information obtained from muscle biopsies by conventional histochemical methods and lead to a better understanding of the mechanisms of muscle damage.

Lectin binding and desmin staining during bupivicaine-induced necrosis and regeneration in rat skeletal muscle

The processes of bupivicaine-induced necrosis and regeneration in rat skeletal muscle have been studied with a panel of biotinylated lectins and by immunohistochemical staining for desmin. The results indicate that the binding of lectins to the periphery of muscle fibres is not altered in necrotic and regenerating fibres at the light microscopic level although abnormal cytoplasmic staining by lectins occurs early in necrosis and is also present during regeneration. Desmin staining is lost at an early stage of necrosis and is present at an early stage of regeneration. Desmin staining in combination with morphometrical assessment of the rate of fusion and growth of regenerating fibres provides a powerful method for evaluating the processes of muscle regeneration in experimental situations.

Effect of nerve stimulation on rat skeletal muscle. A study of plasma membrane

The gastrocnemius muscle of the rat showed no morphological, histometric or plasma membrane changes, after sciatic nerve stimulation with a 5mA current for 30 to 60 min, 10 mA for 30 min and 15 mA for 5 min. However, 10 mA for 60 and 200 min gave rise to mitochondrial and plasma membrane abnormalities. These changes were absent after a rest period. The results indicated that the sciatic nerve stimulation at 10 mA for 60 and 200 min caused reversible changes in the rat skeletal muscle mitochondria and plasma membrane.

Lectin blotting of human muscle. Identification of a high molecular weight glycoprotein which is absent or altered in Duchenne muscular dystrophy

Using a combination of sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) and Western blotting, a high molecular weight Ricinus communis I (RCA I)-binding glycoprotein (approx. Mr 370000) has been identified in human muscle that is consistently altered or absent in muscle from patients with Duchenne muscular dystrophy (DMD). In addition, a Mr 54000 RCA I-binding glycoprotein was identified in 4 out and 8 DMD muscle samples that was not present in normal muscle. The possibility that the Mr 370000 glycoprotein could be a muscle membrane glycoprotein which is altered or absent in DMD is discussed.

Lectin binding in human skeletal muscle: a comparison of 15 different lectins

Fifteen lectin-horseradish peroxidase conjugates have been used in a comprehensive histochemical study of human skeletal muscle. The staining patterns of many lectins were found to be coincident with the known distributions of types I, III, IV and V collagen, fibronectin and laminin. One lectin, Bandeiraea simplicifolia (BSA I), selectively stained capillaries in a blood group-specific manner, the significance of which is unknown. The results show that although lectins are useful cytochemical probes for identifying tissue glycoconjugates, lectin binding is not solely determined by monosaccharide specificity as lectins which interact with the same sugars may have completely different staining patterns. Factors such as accessibility, glycan conformation and oligosaccharide sequence also affect lectin binding in tissues. For these reasons, we conclude that a comprehensive histochemical investigation of tissue glycoconjugates should employ a large number of lectins, preferably with overlapping sugar specificities.

Binding of Ricinus communis I lectin to the muscle cell plasma membrane in diseased muscle

Using an electron histochemical technique, we have observed the binding of a D-galactose-specific lectin to the muscle cell plasma membrane in muscle biopsies taken from patients with various neuromuscular disorders. In spinal muscular atrophy, the only neurogenic disease studied, the plasma membrane stained as in normal muscle. However, in the myopathies Becker and limb-girdle muscular dystrophy and in the polymyositis there was a reduction in both the occurrence and the intensity of staining of the plasma membrane. Reduced lectin binding by the plasma membrane probably reflects secondary changes in the composition of glycoproteins and/or glycolipids in the membrane and seems to be common to all these myopathies to varying degrees.

Diagnostic needle muscle biopsy. A practical and reliable alternative to open biopsy

The technique of needle muscle biopsy using the Bergstr öm needle has been in routine use in our muscle clinic since 1978. In an initial feasibility study 24 children had a needle and an open biopsy performed simultaneously through extension of the same incision and 22 had identical interpretation of the needle and open biopsies. Needle biopsies have subsequently been performed in 674 children and have been satisfactory for diagnostic assessment in 656. The samples have been of adequate size and comparable in quality to our previous open biopsies, with good preservation and orientation. Needle muscle biopsy under local anaesthetic is quicker and less traumatic than open biopsy and leaves only a very small scar. Sufficient muscle can be obtained for routine histological, histochemical, and electronmicroscopic diagnosis, as well as for specialised biochemical and research purposes. There seems little justification for the continued use of open biopsy for routine investigation of neuromuscular disease.

Concanavalin A target cells in human brain tumours

Using a lectin-peroxidase method, Concanavalin A binding was examined on formalin-fixed paraffin-embedded biopsy specimens (n = 143) of the most frequent central nervous system tumours. The brain tumours included oligodendrogliomas, astrocytomas, glioblastomas, ependymomas, neurinomas, meningiomas, medulloblastomas and plexus papillomas. In oligodendroglioma cells, only a weak granular intracytoplasmic staining was observed. The astrocytomas showed a strong reaction in fibrillary astrocytes and in tumour areas undergoing small cystic degeneration. Staining of protoplasmic astrocytes was weaker; pilocytic astrocytes demonstrated poor perinuclear staining. Intracytoplasmic Con A binding in gemistocytic astrocytes was distinct but inconstant and rather diffuse. In the glioblastomas the lymphocyte-like small astrocytes were negative. Giant multinucleated astrocytes stained strongly. In ependymomas no or at most a weak perinuclear reaction was observed, whereas the acceptor density was as high as in the normal ependymocytes in areas where the tumour was capable of producing organotypical structures. Plexus papillomas showed a strong intracytoplasmic staining comparable to the normal plexus epithelial cell. This feature was preserved in the malignant variants. In general, meningiomas and neurinomas were negative. Xanthomatous-degenerated meningioma cells, however, showed a distinct to strong intracytoplasmic staining. This feature was characteristic for the xanthomatous subtype of meningiomas. Granular cells with strong intracytoplasmic Con A staining often occurred at the border of fibrillary to reticular differentiated areas of neurinomas. Medulloblastomas were completely negative. Our results indicate that Con A binding to human brain tumours is specific and rather cytotypical than histotypical . The Con A acceptor density is probably related to the grade of differentiation. Lectin mapping of tumours leads to cytotypical binding patterns which may contribute to the differential diagnosis of neoplasias.

Altered binding of Ricinus communis I lectin by muscle membranes in Duchenne muscular dystrophy

Recently, it has become clear that a structural or functional abnormality of the plasma membrane may be involved in the pathogenesis of Duchenne muscular dystrophy (DMD). We have used a D-galactose specific lectin, that binds strongly to the muscle cell surface, to search for differences in sarcolemmal staining in biopsies from 5 normal and 7 DMD individuals. Electron optical studies revealed a dramatic and consistent decrease in lectin binding by the muscle plasma membrane in DMD. Although unable at this stage to identify the specific molecular abnormality responsible for this decreased staining, the results provide good evidence that a basic structural change within the plasma membrane may be intimately associated with DMD.