Effect of myasthenic patient sera on the number and distribution of acetylcholine receptors in muscle and nerve-muscle cultures from rat

Eymard, B.; Porte, Sabine de la; Pannier, C; Berrih‐Aknin, Sonia; Morel, E.; Fardeau, Michel; Bach, Jean‐François; Koenig, Jeanine

doi:10.1016/0022-510x(88)90006-8

Cited by 21 publications

(6 citation statements)

References 38 publications

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“…The anti-AChR antibody titer was determined using human muscle AChR complexed with '25I-abungarotoxin as antigen (27). Functional activity in MG serum was tested on rat myoblast cultures as previously described (15) and data are expressed as the percentage loss of AChR relative to normal serum (Table I). The severity of MG was graded according to Osserman's classification (28).…”

Section: Methodsmentioning

confidence: 99%

“…Several studies, including work in our laboratory, failed to show a correlation between the severity of the disease and either antibody titers or the functional activity of anti-AChR antibodies in myotube cultures, whereas the ability of patients sera to degrade AChR does correlate with the antibody titer (15,16).…”

Section: Introductionmentioning

confidence: 99%

“…The pathogenicity of anti-AChR antibodies has been clearly demonstrated by their ability to transfer the disease to normal animals (12,13) and to reduce a-bungarotoxin binding sites in a myotube culture system (14)(15)(16). Several studies, including work in our laboratory, failed to show a correlation between the severity of the disease and either antibody titers or the functional activity of anti-AChR antibodies in myotube cultures, whereas the ability of patients sera to degrade AChR does correlate with the antibody titer (15,16).…”

Section: Introductionmentioning

confidence: 99%

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Regulation of acetylcholine receptor alpha subunit variants in human myasthenia gravis. Quantification of steady-state levels of messenger RNA in muscle biopsy using the polymerase chain reaction.

Guyon¹,

Levasseur²,

Truffault³

et al. 1994

J. Clin. Invest.

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Myasthenia gravis (MG) is an autoimmune disease mediated by auto-antibodies that attack the nicotinic acetylcholine receptor (AChR). To elucidate the molecular mechanisms underlying the decrease in AChR levels at the neuromuscular junction, we investigated the regulation of AChR expression by analyzing mRNA of the two AChR a subunit isoforms (P3A+ and P3A-) in muscle samples from myasthenic patients relative to controls. We applied a quantitative method based on reverse transcription of total RNA followed by polymerase chain reaction (PCR), using an internal standard we constructed by site-directed mutagenesis. An increased expression of mRNA coding for the a subunit of the AChR isoforms was observed in severely affected patients (P < 0.003 versus controls) but not in moderately affected patients, independently of the anti-AChR antibody titer. Study of mRNA precursor levels indicates a higher expression in severely affected patients compared to controls, suggesting an enhanced rate of transcription of the message coding for the a subunit isoforms in these patients. We have also reported that mRNA encoding both isoforms are expressed at an approximate 1:1 ratio in controls and in patients. We have thus identified a new biological parameter correlated with disease severity, and provide evidence of a compensatory mechanism to balance the loss of AChR in human myasthenia gravis, which is probably triggered only above a certain degree of AChR loss. (J. Clin. Invest. 1994. 94:16-24.) Key words: acetylcholine receptor isoforms * reg-

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Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Regulation of acetylcholine receptor alpha subunit variants in human myasthenia gravis. Quantification of steady-state levels of messenger RNA in muscle biopsy using the polymerase chain reaction.

Guyon¹,

Levasseur²,

Truffault³

et al. 1994

J. Clin. Invest.

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“…2(c,d)]. The decrease in the number of AChR sites and clusters is similar in muscle cell cultures and nerve–muscle co‐cultures, after treatment by antibodies against AChR [myasthenic patient whole sera or purified immunoglobulins obtained by affinity chromatography (Eymard et al . 1988) or anti‐MIR mAbs (unpublished results)].…”

Section: Resultsmentioning

confidence: 87%

Accumulation of acetylcholine receptors is a necessary condition for normal accumulation of acetylcholinesterase during in vitro neuromuscular synaptogenesis

Porte

Chaubourt

et al. 1998

Eur J of Neuroscience

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To study a step of the very complex processes of the formation of the neuromuscular junction (NMJ), we have analysed the clustering of acetylcholine receptors (AChR) and acetylcholinesterase (AChE) in myotubes cultured in various conditions. On the surface of rat myotubes cultured in the presence of spinal cord cells from embryonic rat, numerous AChE clusters appeared. Such clusters are always co-localized with AChR clusters, but the reverse is not true: the number of AChR clusters largely exceeds that of AChE clusters. Very few AChE clusters formed when such co-cultures were treated with monoclonal antibodies (mAbs) against the main immunogenic region (MIR) of the AChR, which provoke internalization and degradation of the AChRs of the muscular membrane. The total levels of AChE and proportions of molecular forms were unaffected. We also used non-innervated myotubes in which addition of agrin, a protein normally synthesized by motoneurons, transported to nerve terminals and inserted into the synaptic basal lamina, induces the formation of small clusters of AChE. When added to rat myotubes devoid of membrane AChR, agrin-induced AChE clusters did not form. Finally, we analysed the capacity of the variant of the C2 mouse muscle cell line deficient in AChR (1R-) to form clusters of AChE in co-cultures with spinal cord cells from rat: no formation of AChE clusters could be observed. In all these different systems of cultures, the conditions which prevented clustering of AChR (anti-AChR antibodies, deficiency of the variant C2 cell line) also suppressed AChE clustering. We concluded that clustering of AChR is a prerequisite for clustering of AChE, so that NMJ formation implies the sequential accumulation of these two components.

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“…There have been many reports on the role of complement in the pathogenesis of MG and EAMG [5,7,11,12,14,21,22,34,35,38,40]; reports particularly focused on the first component of the complement system [12,13,20,21,39], and on the terminal and lytic components [5,10,30,34]. Unlike the studies done on antigenic modulation of end-plate AChRs, most studies of the role of complement were made on humans or in EAMG in vivo, except for the investigation of Childs et al [7].…”

Section: Discussionmentioning

confidence: 99%

Effect of myasthenic immunoglobulin G on motor end-plate morphology

Tsujihata¹,

Satoh²,

Yoshimura

et al. 2003

Journal of Neurology

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This study was undertaken to clarify the role of complement in acetylcholine receptor loss and degeneration of the postsynaptic membrane in myasthenia gravis (MG). We examined the end-plate morphology in rats with passively transferred immunoglobulin G (IgG) from myasthenic patients and the effect of complement by treatment of the rats with cobra venom factor. We injected peroxidase-labeled alpha-BuTx (P-BuTx) into the extensor digitorum longus (EDL) muscle to label the motor end-plates. Three hours later, 100 mg of IgG from MG patients or healthy controls was injected into the tail vein. The EDL was removed 48 hours after the injection of IgG. The presence of macrophages and degeneration of the postsynaptic membrane were seen in 4 of 6 IgG samples from MG patients and a decrease in AChRs in the other 2 samples. These changes were reversed completely by treatment with cobra venom factor in all but one case in which the end-plates were severely degenerated. Injection of MG IgG only never induced end-plate morphology changes. The results suggest that complement has a critical role in degeneration of the postsynaptic membrane and AChR loss at the motor end-plates in the passively transferred model and probably in human MG.

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Effect of myasthenic patient sera on the number and distribution of acetylcholine receptors in muscle and nerve-muscle cultures from rat

Cited by 21 publications

References 38 publications

Regulation of acetylcholine receptor alpha subunit variants in human myasthenia gravis. Quantification of steady-state levels of messenger RNA in muscle biopsy using the polymerase chain reaction.

Regulation of acetylcholine receptor alpha subunit variants in human myasthenia gravis. Quantification of steady-state levels of messenger RNA in muscle biopsy using the polymerase chain reaction.

Accumulation of acetylcholine receptors is a necessary condition for normal accumulation of acetylcholinesterase during in vitro neuromuscular synaptogenesis

Effect of myasthenic immunoglobulin G on motor end-plate morphology

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