1
|
Autoantibodies Against the Glial Glutamate Transporter GLT1/EAAT2 in Type 1 Diabetes Mellitus. Clues to novel immunological and non-immunological therapies. Pharmacol Res 2022; 177:106130. [DOI: 10.1016/j.phrs.2022.106130] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/11/2022] [Revised: 02/07/2022] [Accepted: 02/08/2022] [Indexed: 11/22/2022]
|
2
|
Bjørn-Yoshimoto WE, Ramiro IBL, Yandell M, McIntosh JM, Olivera BM, Ellgaard L, Safavi-Hemami H. Curses or Cures: A Review of the Numerous Benefits Versus the Biosecurity Concerns of Conotoxin Research. Biomedicines 2020; 8:E235. [PMID: 32708023 PMCID: PMC7460000 DOI: 10.3390/biomedicines8080235] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Revised: 07/17/2020] [Accepted: 07/19/2020] [Indexed: 01/18/2023] Open
Abstract
Conotoxins form a diverse group of peptide toxins found in the venom of predatory marine cone snails. Decades of conotoxin research have provided numerous measurable scientific and societal benefits. These include their use as a drug, diagnostic agent, drug leads, and research tools in neuroscience, pharmacology, biochemistry, structural biology, and molecular evolution. Human envenomations by cone snails are rare but can be fatal. Death by envenomation is likely caused by a small set of toxins that induce muscle paralysis of the diaphragm, resulting in respiratory arrest. The potency of these toxins led to concerns regarding the potential development and use of conotoxins as biological weapons. To address this, various regulatory measures have been introduced that limit the use and access of conotoxins within the research community. Some of these regulations apply to all of the ≈200,000 conotoxins predicted to exist in nature of which less than 0.05% are estimated to have any significant toxicity in humans. In this review we provide an overview of the many benefits of conotoxin research, and contrast these to the perceived biosecurity concerns of conotoxins and research thereof.
Collapse
Affiliation(s)
- Walden E. Bjørn-Yoshimoto
- Department of Biomedical Sciences, University of Copenhagen, 2200 Copenhagen N, Denmark; (W.E.B.-Y.); (I.B.L.R.)
| | - Iris Bea L. Ramiro
- Department of Biomedical Sciences, University of Copenhagen, 2200 Copenhagen N, Denmark; (W.E.B.-Y.); (I.B.L.R.)
| | - Mark Yandell
- Eccles Institute of Human Genetics, University of Utah, Salt Lake City, UT 84112, USA;
- Utah Center for Genetic Discovery, University of Utah, Salt Lake City, UT 84112, USA
| | - J. Michael McIntosh
- School of Biological Sciences, University of Utah, Salt Lake City, UT 84112, USA; (J.M.M.); (B.M.O.)
- George E. Whalen Veterans Affairs Medical Center, Salt Lake City, UT 84148, USA
- Department of Psychiatry, University of Utah, Salt Lake City, UT 84108, USA
| | - Baldomero M. Olivera
- School of Biological Sciences, University of Utah, Salt Lake City, UT 84112, USA; (J.M.M.); (B.M.O.)
| | - Lars Ellgaard
- Department of Biology, Linderstrøm-Lang Centre for Protein Science, University of Copenhagen, 2200 Copenhagen N, Denmark;
| | - Helena Safavi-Hemami
- Department of Biomedical Sciences, University of Copenhagen, 2200 Copenhagen N, Denmark; (W.E.B.-Y.); (I.B.L.R.)
- School of Biological Sciences, University of Utah, Salt Lake City, UT 84112, USA; (J.M.M.); (B.M.O.)
- Department of Biochemistry, University of Utah, Salt Lake City, UT 84112, USA
| |
Collapse
|
3
|
Ishida N, Kondo Y, Chikano Y, Kobayashi‐Nakade E, Suga Y, Ishizaki J, Komai K, Matsushita R. Pharmacokinetics and tissue distribution of 3,4‐diaminopyridine in rats. Biopharm Drug Dispos 2019; 40:294-301. [DOI: 10.1002/bdd.2203] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2019] [Revised: 07/12/2019] [Accepted: 08/09/2019] [Indexed: 11/05/2022]
Affiliation(s)
- Natsuko Ishida
- Faculty of Pharmacy, Institute of Medical, Pharmaceutical and Health SciencesKanazawa University Kakuma‐machi Kanazawa Ishikawa 920‐1192 Japan
- Department of Clinical Research, Iou National HospitalNational Hospital Organization Ishikawa Japan
| | - Yuya Kondo
- Faculty of Pharmacy, Institute of Medical, Pharmaceutical and Health SciencesKanazawa University Kakuma‐machi Kanazawa Ishikawa 920‐1192 Japan
| | - Yuri Chikano
- Faculty of Pharmacy, Institute of Medical, Pharmaceutical and Health SciencesKanazawa University Kakuma‐machi Kanazawa Ishikawa 920‐1192 Japan
| | - Erina Kobayashi‐Nakade
- Faculty of Pharmacy, Institute of Medical, Pharmaceutical and Health SciencesKanazawa University Kakuma‐machi Kanazawa Ishikawa 920‐1192 Japan
| | - Yukio Suga
- Faculty of Pharmacy, Institute of Medical, Pharmaceutical and Health SciencesKanazawa University Kakuma‐machi Kanazawa Ishikawa 920‐1192 Japan
| | - Junko Ishizaki
- Faculty of Pharmacy, Institute of Medical, Pharmaceutical and Health SciencesKanazawa University Kakuma‐machi Kanazawa Ishikawa 920‐1192 Japan
| | - Kiyonobu Komai
- Department of Neurology, Hokuriku Brain and Neuromuscular Disease Center, Iou National HospitalNational Hospital Organization Ishikawa Japan
| | - Ryo Matsushita
- Faculty of Pharmacy, Institute of Medical, Pharmaceutical and Health SciencesKanazawa University Kakuma‐machi Kanazawa Ishikawa 920‐1192 Japan
| |
Collapse
|
4
|
Schoser B, Eymard B, Datt J, Mantegazza R. Lambert–Eaton myasthenic syndrome (LEMS): a rare autoimmune presynaptic disorder often associated with cancer. J Neurol 2017; 264:1854-1863. [DOI: 10.1007/s00415-017-8541-9] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2017] [Revised: 06/06/2017] [Accepted: 06/07/2017] [Indexed: 10/19/2022]
|
5
|
Lambert–Eaton myasthenic syndrome – Diagnosis, pathogenesis and therapy. Clin Neurophysiol 2014; 125:2328-36. [DOI: 10.1016/j.clinph.2014.06.031] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2014] [Revised: 06/05/2014] [Accepted: 06/26/2014] [Indexed: 02/07/2023]
|
6
|
Small cell lung cancer presenting as severe thrombocytopenia and refractory hypokalemia. Case Rep Oncol Med 2014; 2014:874831. [PMID: 24959367 PMCID: PMC4052468 DOI: 10.1155/2014/874831] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2014] [Accepted: 05/05/2014] [Indexed: 11/25/2022] Open
Abstract
A 70-year-old female with a history of mild cirrhosis was referred by her primary care provider for a platelet count of 36,000/μL which had dropped from 47,000/μL in a week along with mild pain in extremities. Serum potassium was low (2.9 mEq/L) in spite of the patient being recently started on potassium supplement on outpatient for hypokalemia. Initially thrombocytopenia was attributed to cirrhosis. However, platelet counts continued to drop to a nadir of 9000/μL in spite of several platelet transfusions. Hypokalemia was refractory to potassium supplements. Subsequent bone marrow biopsy revealed extensive marrow necrosis with a focus of small cell tumor cells of pulmonary origin. CT scan of the chest showed a spiculated left lung mass. The ACTH level was high, with normal rennin and aldosterone levels. The patient likely had ectopic ACTH syndrome from small cell lung cancer. She died within few days of diagnosis. Severe thrombocytopenia and refractory hypokalemia can rarely be initial presentations of small cell lung cancer. Thrombocytopenia should prompt an evaluation for bone marrow metastases and a search for undiagnosed systemic malignancy. In severe cases of metastases, bone marrow necrosis can be present. Refractory hypokalemia can be the sole presentation of ectopic ACTH production.
Collapse
|
7
|
Lang B, Willcox N. Autoantibodies in neuromuscular autoimmune disorders. Expert Rev Clin Immunol 2014; 2:293-307. [DOI: 10.1586/1744666x.2.2.293] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
|
8
|
Kleopa KA. Autoimmune channelopathies of the nervous system. Curr Neuropharmacol 2012; 9:458-67. [PMID: 22379460 PMCID: PMC3151600 DOI: 10.2174/157015911796557966] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2010] [Revised: 03/16/2010] [Accepted: 03/16/2010] [Indexed: 12/20/2022] Open
Abstract
Ion channels are complex transmembrane proteins that orchestrate the electrical signals necessary for normal function of excitable tissues, including the central nervous system, peripheral nerve, and both skeletal and cardiac muscle. Progress in molecular biology has allowed cloning and expression of genes that encode channel proteins, while comparable advances in biophysics, including patch-clamp electrophysiology and related techniques, have made the functional assessment of expressed proteins at the level of single channel molecules possible. The role of ion channel defects in the pathogenesis of numerous disorders has become increasingly apparent over the last two decades. Neurological channelopathies are frequently genetically determined but may also be acquired through autoimmune mechanisms. All of these autoimmune conditions can arise as paraneoplastic syndromes or independent from malignancies. The pathogenicity of autoantibodies to ion channels has been demonstrated in most of these conditions, and patients may respond well to immunotherapies that reduce the levels of the pathogenic autoantibodies. Autoimmune channelopathies may have a good prognosis, especially if diagnosed and treated early, and if they are non-paraneoplastic. This review focuses on clinical, pathophysiologic and therapeutic aspects of autoimmune ion channel disorders of the nervous system.
Collapse
Affiliation(s)
- Kleopas A Kleopa
- Neurology Clinics and Neuroscience Laboratory, The Cyprus Institute of Neurology and Genetics, Cyprus
| |
Collapse
|
9
|
Conotoxins that confer therapeutic possibilities. Mar Drugs 2012; 10:1244-1265. [PMID: 22822370 PMCID: PMC3397437 DOI: 10.3390/md10061244] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2012] [Revised: 04/24/2012] [Accepted: 05/24/2012] [Indexed: 12/19/2022] Open
Abstract
Cone snails produce a distinctive repertoire of venom peptides that are used both as a defense mechanism and also to facilitate the immobilization and digestion of prey. These peptides target a wide variety of voltage- and ligand-gated ion channels, which make them an invaluable resource for studying the properties of these ion channels in normal and diseased states, as well as being a collection of compounds of potential pharmacological use in their own right. Examples include the United States Food and Drug Administration (FDA) approved pharmaceutical drug, Ziconotide (Prialt®; Elan Pharmaceuticals, Inc.) that is the synthetic equivalent of the naturally occurring ω-conotoxin MVIIA, whilst several other conotoxins are currently being used as standard research tools and screened as potential therapeutic drugs in pre-clinical or clinical trials. These developments highlight the importance of driving conotoxin-related research. A PubMed query from 1 January 2007 to 31 August 2011 combined with hand-curation of the retrieved articles allowed for the collation of 98 recently identified conotoxins with therapeutic potential which are selectively discussed in this review. Protein sequence similarity analysis tentatively assigned uncharacterized conotoxins to predicted functional classes. Furthermore, conotoxin therapeutic potential for neurodegenerative disorders (NDD) was also inferred.
Collapse
|
10
|
Vincent A. John Newsom-Davis: clinician-scientist and so much more. Brain 2011; 134:3755-74. [PMID: 22171357 PMCID: PMC3235562 DOI: 10.1093/brain/awr284] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2011] [Revised: 09/07/2011] [Accepted: 09/08/2011] [Indexed: 01/17/2023] Open
Abstract
John Newsom-Davis was born in 1932 and died, aged 74, in 2007. After national service in the Royal Air Force, he read Natural Sciences at Cambridge. Following clinical studies at the Middlesex Hospital, he began research into respiratory neurophysiology with Tom Sears at the National Hospital, Queen Square, in London, and spent 1 year with Fred Plum at Cornell University in New York. After neurology specialist training at Queen Square, he became the director of the Batten Unit, continuing his interest in respiratory physiology. There he began to work on myasthenia gravis in collaboration with Ricardo Miledi at University College London and in 1978, after performing the first studies on plasma exchange in that disease, he established a myasthenia gravis research group at the Royal Free Hospital. There he investigated the role of the thymus in this disease and demonstrated an autoimmune basis for the Lambert Eaton myasthenic syndrome and 'seronegative' myasthenia. He was awarded the first Medical Research Council Clinical Research Professorship in 1979 but moved to Oxford in 1987 when he was elected Action Research Professor of Neurology. While at Oxford, he continued to run a very successful multidisciplinary group, researched further into the thymic abnormalities and cellular immunology of myasthenia, identified antibody-mediated mechanisms in acquired neuromyotonia, and began the molecular work that identified the genetic basis for many forms of congenital myasthenic syndrome. Meanwhile, he was also involved in university and college governance and contributed widely to the Medical Research Council, government committees, research charities and the Association of British Neurologists. Among many honours, he was elected Fellow of the Royal Society in 1991, appointed Commander of the British Empire in 1996 and made a Foreign Associate Member of the Institute of Medicine of the United States in 2001. Nearing and following retirement from Oxford, where he continued to see patients with myasthenia, he was the President of the Association of British Neurologists and Editor of Brain, and led a National Institutes of Health-funded international trial of thymectomy.
Collapse
Affiliation(s)
- Angela Vincent
- Nuffield Department of Clinical Neurosciences, John Radcliffe Hospital, Oxford OX3 9DU, UK.
| |
Collapse
|
11
|
Martin-Moutot N, De Haro L, Seagar M. Distinct evolution of calcium channel antibody types in Lambert-Eaton myasthenic syndrome. J Neuroimmunol 2008; 197:47-53. [PMID: 18474401 DOI: 10.1016/j.jneuroim.2008.04.001] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2007] [Revised: 03/17/2008] [Accepted: 04/01/2008] [Indexed: 02/06/2023]
Abstract
To determine whether titers of anti-P/Q type and anti-N type calcium channel antibodies provide distinct information, both types of assay were performed during follow-up of 7 patients with Lambert-Eaton myasthenic syndrome (LEMS). In 4 patients with both antibody responses, titers evolved independently and often in an inverse relationship. Two patients with squamous cell lung carcinoma (SqCLC) produced anti-N type channel antibodies, but no detectable anti-P/Q channel responses. These results suggest that anti-N channel autoantibodies constitute an immune response distinct from the anti-P/Q type channel specificity and can also correlate with clinical evolution. Consequently combined assays may provide more comprehensive information during follow-up of LEMS.
Collapse
|
12
|
Anti-Ca2+ channel antibody attenuates Ca2+ currents and mimics cerebellar ataxia in vivo. Proc Natl Acad Sci U S A 2008; 105:2705-10. [PMID: 18272482 DOI: 10.1073/pnas.0710771105] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Voltage-gated Ca(2+) channels (VGCCs) are membrane proteins that determine the activity and survival of neurons, and mutations in the P/Q-type VGCCs are known to cause cerebellar ataxia. VGCC dysfunction may also underlie acquired peripheral and central nervous system diseases associated with small-cell lung cancer, including Lambert-Eaton myasthenic syndrome (LEMS) and paraneoplastic cerebellar ataxia (PCA). The pathogenic role of anti-VGCC antibody in LEMS is well established. Although anti-VGCC antibody is also found in a significant fraction of PCA patients, its contribution to PCA is unclear. Using a polyclonal peptide antibody against a major immunogenic region in P/Q-type VGCCs (the extracellular Domain-III S5-S6 loop), we demonstrated that such antibody was sufficient to inhibit VGCC function in neuronal and recombinant VGCCs, alter cerebellar synaptic transmission, and confer the phenotype of cerebellar ataxia. Our data support the hypothesis that anti-VGCC antibody may play a significant role in the pathogenesis of cerebellar dysfunction in PCA.
Collapse
|
13
|
Vincent A. Autoantibodies in different forms of myasthenia gravis and in the Lambert-Eaton syndrome. HANDBOOK OF CLINICAL NEUROLOGY 2008; 91:213-227. [PMID: 18631844 DOI: 10.1016/s0072-9752(07)01506-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Affiliation(s)
- Angela Vincent
- Department of Clinical Neurology, University of Oxford, Oxford, UK.
| |
Collapse
|
14
|
Nomiyama K, Uchino A, Yakushiji Y, Kosugi M, Takase Y, Kudo S. Diffuse cranial nerve and cauda equina lesions associated with breast cancer. Clin Imaging 2007; 31:202-5. [PMID: 17449382 DOI: 10.1016/j.clinimag.2007.01.006] [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] [Received: 10/30/2006] [Accepted: 01/06/2007] [Indexed: 11/26/2022]
Abstract
We report on the case of a patient with breast cancer with diffuse cranial nerve and cauda equina lesions. Magnetic resonance imaging of the patient's brain and spinal cord showed diffuse abnormal enhancement and slight enlargement of the cranial nerves and cauda equina. Although the results of subsequent testing for two antineural antibodies were negative, paraneoplastic sensorimotor neuropathy associated with breast cancer was considered to be the most likely clinical diagnosis.
Collapse
Affiliation(s)
- Keita Nomiyama
- Department of Radiology, Saga Medical School, Saga 849-8501, Japan.
| | | | | | | | | | | |
Collapse
|
15
|
Oh SJ, Hatanaka Y, Claussen GC, Sher E. Electrophysiological differences in seropositive and seronegative Lambert-Eaton myasthenic syndrome. Muscle Nerve 2007; 35:178-83. [PMID: 17058271 DOI: 10.1002/mus.20672] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
In order to determine whether there is any difference between voltage-gated calcium-channel antibody (VGCC-Ab)-positive and -negative groups in Lambert-Eaton myasthenic syndrome (LEMS), we compared the clinical and electrophysiological features between 13 patients with VGCC-Ab and 6 VGCC-Ab-negative patients. No obvious difference was observed in the various clinical features or findings on single-fiber electromyography between seropositive and seronegative cases. In seropositive cases, the compound muscle action potential (CMAP) amplitude was lower but the increment on post-exercise facilitation (PEF) and high-rate stimulation (HRS) was significantly higher than in the seronegative group, indicating that the repetitive nerve stimulation (RNS) test in the seropositive group is more typical of LEMS and more severe. A 100% increment as the diagnostic criterion in the routine RNS test was satisfied in all seropositive cases but in only three seronegative cases, whereas a 60% increment as the diagnostic criterion was found in all seronegative cases. The classic triad (low CMAP amplitude, decrement at low rate of stimulation, and increment at PEF or HRS) of RNS is rare, adding to the difficulty in diagnosing LEMS in the seronegative group, and making a 60% increment criterion more critical for the diagnosis of this disorder.
Collapse
Affiliation(s)
- Shin J Oh
- Department of Neurology, University of Alabama at Birmingham, Veterans Affairs Medical Center, UAB Station, Birmingham, Alabama 35294, USA.
| | | | | | | |
Collapse
|
16
|
Abstract
Ion channels are crucial elements in neuronal signaling and synaptic transmission, and defects in their function are known to underlie rare genetic disorders, including some forms of epilepsy. A second class of channelopathies, characterized by autoantibodies against ligand- and voltage-gated ion channels, cause a variety of defects in peripheral neuromuscular and ganglionic transmission. There is also emerging evidence for autoantibody-mediated mechanisms in subgroups of patients with central nervous system disorders, particularly those involving defects in cognition or sleep and often associated with epilepsy. In all autoimmune channelopathies, the relationship between autoantibody specificity and clinical phenotype is complex. But with this new information, autoimmune channelopathies are detected and treated with increasing success, and future research promises new insights into the mechanisms of dysfunction at neuronal synapses and the determinants of clinical phenotype.
Collapse
Affiliation(s)
- Angela Vincent
- Neurosciences Group, Department of Clinical Neurology, Weatherall Institute of Molecular Medicine, John Radcliffe Hospital, Oxford OX3 9DS, United Kingdom.
| | | | | |
Collapse
|
17
|
Martin-Moutot N, Haro LD, Santos RGD, Mori Y, Seagar M. Phoneutria nigriventer ω-Phonetoxin IIA: A new tool for anti-calcium channel autoantibody assays in Lambert–Eaton myasthenic syndrome. Neurobiol Dis 2006; 22:57-63. [PMID: 16289869 DOI: 10.1016/j.nbd.2005.10.003] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2005] [Revised: 09/02/2005] [Accepted: 10/05/2005] [Indexed: 11/30/2022] Open
Abstract
Lambert-Eaton myasthenic syndrome (LEMS) is a neurological autoimmune disease in which downregulation of voltage-gated calcium channels (VGCCs) leads to reduced acetylcholine release from motoneuron terminals. 70% of cases are paraneoplastic and rapid diagnosis of LEMS can result in early detection of the underlying tumor. Serological assays based on the capacity of autoantibodies to precipitate VGCCs labeled with radioligands provide valuable data. We have established a novel assay using the spider venom peptide 125I-omega-Phonetoxin IIA (125I-omegaPtxIIA). 125I-omegaPtxIIA labeled recombinant Cav2.1 and Cav2.2 channels and endogenous VGCCs in rat brain membranes. Autoantibodies that immunoprecipitate a 125I-omegaPtxIIA/channel complex were detected in 26/31 (84%) LEMS patients. The patients that were seropositive in the 125I-omegaPtxIIA assay corresponded precisely to the population that was positive for Cav2.1 and/or Cav2.2 antibodies detected using two different omega-conotoxins. Thus, the 125I-omegaPtxIIA assay detects a broader spectrum of autoantibody specificities than current omega-conotoxin-based assays.
Collapse
|
18
|
Abstract
Small-cell lung carcinoma is an aggressive form of lung cancer that is strongly associated with cigarette smoking and has a tendency for early dissemination. Increasing evidence has implicated autocrine growth loops, proto-oncogenes, and tumour-suppressor genes in its development. At presentation, the vast majority of patients are symptomatic, and imaging typically reveals a hilar mass. Pathology, in most cases of samples obtained by bronchoscopic biopsy, should be undertaken by pathologists with pulmonary expertise, with the provision of additional tissue for immunohistochemical stains as needed. Staging should aim to identify any evidence of distant disease, by imaging of the chest, upper abdomen, head, and bones as appropriate. Limited-stage disease should be treated with etoposide and cisplatin and concurrent early chest irradiation. All patients who achieve complete remission should be considered for treatment with prophylactic cranial irradiation, owing to the high frequency of brain metastases in this disease. Extensive-stage disease should be managed by combination chemotherapy, with a regimen such as etoposide and cisplatin administered for four to six cycles. Thereafter, patients with progressive or recurrent disease should be treated with additional chemotherapy. For patients who survive long term, careful monitoring for development of a second primary tumour is necessary, with further investigation and treatment as appropriate.
Collapse
Affiliation(s)
- David M Jackman
- Dana Farber Cancer Institute and Department of Medicine, Brigham and Women's Hospital, Boston, MA 02115, USA.
| | | |
Collapse
|
19
|
Oh SJ, Sher E. MG and LEMS overlap syndrome: case report with electrophysiological and immunological evidence. Clin Neurophysiol 2005; 116:1167-71. [PMID: 15826858 DOI: 10.1016/j.clinph.2004.12.013] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2004] [Revised: 11/18/2004] [Accepted: 12/09/2004] [Indexed: 10/25/2022]
Abstract
OBJECTIVE To report the clinical, electrophysiological, and immunological findings in one patient with MG and LEMS overlap syndrome (myasthenia gravis and Lambert-Eaton myasthenic syndrome). METHODS Evaluation of clinical, electrophysiological, and immunological findings in one patient with this disease. RESULTS A female patient with pernicious anemia had clinical findings of ptosis, diplopia, proximal leg weakness, areflexia and a positive edrophonium test as well as the classic patterns initially of MG and later of LEMS on successive repetitive nerve stimulation (RNS) tests. Immunologically she demonstrated positive acetylcholine receptor antibody (ACh-ab) and positive N-type voltage-gated calcium-channel antibody (VGCC-ab) titers. CONCLUSIONS Among five reported cases combining the features of MG and LEMS and having positive AChR- and VGCC-ab titers, our patient provides the most convincing clinical, electrophysiological, and immunological evidence for the existence of MG and LEMS overlap syndrome. SIGNIFICANCE MG and LEMS overlap syndrome is a distinct entity.
Collapse
Affiliation(s)
- Shin J Oh
- Department of Neurology, The University of Alabama at Birmingham, 35294, USA.
| | | |
Collapse
|
20
|
Abstract
Neurodegeneration induced by excitatory neurotransmitter glutamate is considered to be of particular relevance in several types of acute and chronic neurological impairments ranging from cerebral ischaemia to neuropathological conditions such as motor neuron disease, Alzheimer's, Parkinson's disease and epilepsy. The hyperexcitation of glutamate receptors coupled with calcium overload can be prevented or modulated by using well-established competitive and non-competitive antagonists targeting ion/receptor channels. The exponentially increasing body of pharmacological evidence over the years indicates potential applications of peptide toxins, due to their exquisite subtype selectivity on ion channels and receptors, as lead structures for the development of drugs for the treatment of wide variety of neurological disorders. This review comprehensively highlights the overview of the diversity in the molecular as well as neurobiological mechanisms of different peptide toxins derived from venomous animals with particular reference to neuroprotection. In addition, the potential applications of peptide toxins in the diagnosis and treatment of neurological disorders such as neuromuscular disorders, epilepsy, Alzheimer's and Parkinson's diseases, gliomas and ischaemic stroke and their future prospects in the diagnosis as well as in the therapy are addressed.
Collapse
Affiliation(s)
- Wudayagiri Rajendra
- Department of Biochemistry, Faculty of Medicine, National University of Singapore, 8 Medical Drive, Singapore 117597, Singapore
| | | | | |
Collapse
|
21
|
Abstract
Small cell lung carcinoma typically presents as a central endobronchial lesion in chronic cigarette smokers with hilar enlargement and disseminated disease. The diagnostic pathology should be reviewed by a pathologist accomplished in reading pulmonary pathology, and, if any doubt exists in the diagnosis, additional special stains or diagnostic material should be obtained. Patients with extensive stage disease should be managed by combination chemotherapy, whereas patients with limited stage disease should be treated with etoposide/cisplatin plus concurrent chest irradiation. The chemotherapy should be administered for 4 to 6 months and then should be discontinued. Prophylactic cranial irradiation should be given to patients who achieve a complete remission. Patients should be retreated with chemotherapy if they develop a relapse of their small cell lung cancer. The patients who are followed in complete remission should be observed carefully for second cancers, and appropriate therapy should be administered if the cancer reappears.
Collapse
Affiliation(s)
- Bruce E Johnson
- Lowe Center for Thoracic Oncology, Department of Adult Oncology, Dana Farber Cancer Institute, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, USA.
| |
Collapse
|
22
|
Abstract
Lambert-Eaton myasthenic syndrome (LEMS) is an autoimmune disorder characterized by muscle weakness and autonomic dysfunction. Recent ex vivo and in vitro studies demonstrate that autoantibodies to the P/Q-subtype of voltage-gated calcium channel inhibit transmitter release from parasympathetic, sympathetic, and enteric neurons, a mechanism likely to underlie the widespread autonomic dysfunction in LEMS. This review summarizes clinical studies characterizing the autonomic symptoms and signs in LEMS and the effectiveness of treatment in alleviating these symptoms. Serological assays and in vitro pharmacologic and electrophysiologic studies are also discussed.
Collapse
Affiliation(s)
- S A Waterman
- Department of Immunology, Allergy and Arthritis, Flinders Medical Centre, Bedford Park, South Australia, Australia.
| |
Collapse
|
23
|
Parsons KT, Kwok WW, Gaur LK, Nepom GT. Increased frequency of HLA class II alleles DRB1*0301 and DQB1*0201 in Lambert-Eaton myasthenic syndrome without associated cancer. Hum Immunol 2000; 61:828-33. [PMID: 10980394 DOI: 10.1016/s0198-8859(00)00135-x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Lambert-Eaton myasthenic syndrome (LEMS) is a rare autoimmune neuromuscular disorder characterized by pathogenic autoantibodies directed against the presynaptic voltage-gated calcium channels (VGCC), resulting in a clinical syndrome of proximal muscular weakness and autonomic dysfunction. Sixty percent of LEMS cases are associated with cancer, most commonly small cell carcinoma of the lung. In the 40% of LEMS patients without carcinoma, the stimulus for the production of VGCC autoantibodies is unknown; however, these LEMS patients have multiple other organ-specific autoantibodies. To investigate the autoimmune basis of noncancer associated LEMS (NCA-LEMS), high resolution typing of major histocompatibility loci was performed in 23 patients with NCA-LEMS. NCA-LEMS was strongly associated with DRB1*0301 (p<0.0001) and DQB1*0201 (p<0.0001), suggesting that NCA-LEMS is an autoimmune disorder associated with the DR3-DQ2 extended haplotype.
Collapse
Affiliation(s)
- K T Parsons
- Virginia Mason Research Center, Seattle, Washington, USA.
| | | | | | | |
Collapse
|
24
|
Raymond C, Walker D, Bichet D, Iborra C, Martin-Moutot N, Seagar M, De Waard M. Antibodies against the beta subunit of voltage-dependent calcium channels in Lambert-Eaton myasthenic syndrome. Neuroscience 1999; 90:269-77. [PMID: 10188953 DOI: 10.1016/s0306-4522(98)00378-9] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Lambert-Eaton myasthenic syndrome is an autoimmune disease that impairs neuromuscular transmission. Several studies suggest that neurotransmitter release is reduced by an immune response directed against the calcium channel complex of nerve terminals. The immunoglobulin G fractions from Lambert-Eaton myasthenic syndrome patients immunoprecipitate solubilized neuronal N- and P/Q-type channels and in certain cases brain, skeletal and cardiac muscle L-type channels [El Far O. et al. (1995) J. Neurochem. 64, 1696-1702; Lennon V. A. and Lambert E. H. (1989) Mayo Clin. Proc. 64, 1498-1504; Sher E. et al. (1989) Lancet ii, 640-643; Suenaga A. et al. (1996) Muscle Nerve 19, 1166-1168]. These channel immunoprecipitation assays are considered as useful for the diagnosis of this syndrome. In this study, we demonstrate that two predominant neuronal voltage-dependent calcium channel beta subunits (beta3 and beta4, of mol. wt 58,000) are general targets of Lambert-Eaton myasthenic syndrome autoantibodies. Of 20 disease sera tested, 55% were able to immunoprecipitate 35S-labeled beta subunits. All five patients affected with small-cell lung carcinoma were positive for the beta-subunit immunoprecipitation assay. Interestingly, only a fraction of the beta-subunit-positive sera was also able to immunoprecipitate N- and P/Q-type channels, suggesting that several of the beta-subunit epitopes are masked in native channels. In accordance with this observation, we found that several beta-positive sera were able to prevent the interaction between calcium channel alpha1 and beta subunits in vitro. In cases where sera were able to immunoprecipitate beta subunits, N- and P/Q-type channels, the immunoprecipitation of both channel types was either partially or entirely mediated by beta-subunit antibodies. Our results suggest that assays based on the immunoprecipitation of beta subunits can be used as an additional test to assist in the diagnosis of Lambert-Eaton myasthenic syndrome.
Collapse
Affiliation(s)
- C Raymond
- INSERM U464, Laboratoire de Neurobiologie des Canaux Ioniques, Institut Fédératif Jean Roche, Faculté de Médecine Nord, Marseille, France
| | | | | | | | | | | | | |
Collapse
|
25
|
Abstract
Ion channel defects produce a clinically diverse set of disorders that range from cystic fibrosis and some forms of migraine to renal tubular defects and episodic ataxias. This review discusses diseases related to impaired function of the skeletal muscle acetylcholine receptor and calcium channels of the motor nerve terminal. Myasthenia gravis is an autoimmune disease caused by antibodies directed toward the skeletal muscle acetylcholine receptor that compromise neuromuscular transmission. Congenital myasthenias are genetic disorders, a subset of which are caused by mutations of the acetylcholine receptor. Lambert-Eaton myasthenic syndrome is an immune disorder characterized by impaired synaptic vesicle release likely related to a defect of calcium influx. The disorders will illustrate new insights into synaptic transmission and ion channel structure that are relevant for all ion channel disorders.
Collapse
Affiliation(s)
- K Boonyapisit
- Department of Neurology, Case Western Reserve University School of Medicine, Department of Veterans Affairs Medical Center in Cleveland, University Hospitals of Cleveland, Ohio 44106, USA
| | | | | |
Collapse
|
26
|
Scola RH, Iwamoto FM, Ramos CS, Sanderson AM, Lopardo D, Cantarelli A, Watanabe M, Horta W, Werneck LC. Lambert-Eaton myasthenic syndrome. Report of two cases. ARQUIVOS DE NEURO-PSIQUIATRIA 1998; 56:457-64. [PMID: 9754429 DOI: 10.1590/s0004-282x1998000300017] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Two cases of Lambert-Eaton myasthenic syndrome, in female patients whose neoplasm investigation was negative, are reported. Repetitive stimulation of ulnar nerve showed an incremental response (+187% and +198%). Needle EMG was normal in one of them, however, the other patient showed fibrillation potentials, positive sharp waves, potentials of low amplitude and short duration. The authors discuss the clinical, electrophysiological, and pathological features of the disease, as well as some aspects of the treatment and follow-up of these patients.
Collapse
Affiliation(s)
- R H Scola
- Serviço de Doenças Neuromusculares do Hospital de Clínicas da Universidade Federal do Paraná, Brasil
| | | | | | | | | | | | | | | | | |
Collapse
|
27
|
Xu YF, Hewett SJ, Atchison WD. Passive transfer of Lambert-Eaton myasthenic syndrome induces dihydropyridine sensitivity of ICa in mouse motor nerve terminals. J Neurophysiol 1998; 80:1056-69. [PMID: 9744921 DOI: 10.1152/jn.1998.80.3.1056] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Mice were injected for 30 days with plasma from three patients with Lambert-Eaton Myasthenic Syndrome (LEMS). Recordings were made from the perineurial sheath of motor axon terminals of triangularis sterni muscle preparations. The objective was to characterize pharmacologically the identity of kinetically distinct, defined potential changes associated with motor nerve terminal Ca2+ currents (ICa) that were affected by LEMS autoantibodies. ICa elicited at 0.01 Hz were significantly reduced in amplitude by approximately 35% of control in LEMS-treated nerve terminals. During 10-Hz stimulation, ICa amplitude was unchanged in LEMS-treated motor nerve terminals, but was depressed in control. During 20- or 100-Hz trains, facilitation of ICa occurred in LEMS-treated nerve terminals whereas in control, no facilitation occurred during the trains at 20 Hz and marked depression occurred at 100 Hz. Saturation for amplitude and duration of ICa in control terminals occurred at 2 and 4-6 mM extracellular Ca2+, respectively; in LEMS-treated terminals, the extracellular Ca2+ concentration had to increase by two to three times of control to cause saturation. Amplitude of the two components of ICa observed when the preparation was exposed to 50 microM 3,4-diaminopyridine and 1 mM tetraethylammonium were both reduced by LEMS plasma treatment. The fast component (ICa,s) was reduced by 35%, whereas the slow component (ICa, s) was reduced by 37%. omega-Agatoxin IVA (omega-Aga-IVA; 0.15 microM) and omega-conotoxin-MVIIC (omega-CTx-MVIIC; 5 microM) completely blocked ICa in control motor nerve terminals. The same concentrations of toxins were 20-30% less effective in blocking ICa in LEMS-treated terminals. The residual ICa remaining after treatment with omega-Aga-IVA or omega-CTx-MVIIC was blocked by 10 microM nifedipine and 10 microM Cd2+. Thus LEMS plasma appears to downregulate omega-Aga-IVA-sensitive (P-type) and/or omega-CTx-MVIIC-sensitive (Q-type) Ca2+ channels in murine motor nerve terminals, whereas dihydropyridine (DHP)-sensitive (L-type) Ca2+ channels are unmasked in these terminals. Acute exposure (90 min) of rat forebrain synaptosomes to LEMS immunoglobulins (Igs; 4 mg/ml) did not alter the binding of [3H]-nitrendipine or [125I]-omega-conotoxin-GVIA (-omega-CgTx GVIA) when compared with synaptosomes incubated with an equivalent concentration of control Igs. Conversely, LEMS Igs significantly decreased the Bmax for [3H]-verapamil to approximately 45% of control. The apparent affinity of verapamil (KD) for the remaining receptors was not significantly altered. Thus acute exposure of isolated central nerve terminals to LEMS Igs does not increase DHP sensitivity, whereas it reduces the number of binding sites for verapamil but not for nitrendipine or omega-CgTx-GVIA. These results suggest that chronic but not acute exposure to LEMS Igs either upregulates or unmasks DHP-sensitive Ca2+ channels in motor nerve endings.
Collapse
Affiliation(s)
- Y F Xu
- Department of Pharmacology and Toxicology, Michigan State University, East Lansing 48824-1317, USA
| | | | | |
Collapse
|
28
|
Sher E, Rosa P, Francolini M, Codignola A, Morlacchi E, Taverna E, Giovannini F, Brioschi A, Clementi F, McEnery MW, Passafaro M. Metabolism and trafficking of N-type voltage-operated calcium channels in neurosecretory cells. J Bioenerg Biomembr 1998; 30:399-407. [PMID: 9758335 DOI: 10.1023/a:1021945907635] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
The N-type voltage-operated calcium channel has been characterized over the years as a high-threshold channel, with variable inactivation kinetics, and a unique ability to bind with high affinity and specificity omega-conotoxin GVIA and related toxins. This channel is particularly expressed in some neurons and endocrine cells, where it participates in several calcium-dependent processes, including secretion. Omega-conotoxin GVIA was instrumental not only for the biophysical and pharmacological characterization of N-type channels but also for the development of in vitro assays for studying N-type VOCC subcellular localization, biosynthesis, turnover, as well as short-and long-term regulation of its expression. We here summarize our studies on N-type VOCC expression in neurosecretory cells, with a major emphasis on recent data demonstrating the presence of N-type channels in intracellular secretory organelles and their recruitment to the cell surface during regulated exocytosis.
Collapse
Affiliation(s)
- E Sher
- CNR Center of Cellular and Molecular Pharmacology, Department of Medical Pharmacology, University of Milan, Italy
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
29
|
Sher E, Codignola A, Passafaro M, Tarroni P, Magnelli V, Carbone E, Clementi F. Nicotinic receptors and calcium channels in small cell lung carcinoma. Functional role, modulation, and autoimmunity. Ann N Y Acad Sci 1998; 841:606-24. [PMID: 9668305 DOI: 10.1111/j.1749-6632.1998.tb10993.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- E Sher
- CNR Cellular and Molecular Pharmacology Center, Department of Medical Pharmacology, University of Milan, Italy
| | | | | | | | | | | | | |
Collapse
|
30
|
Passafaro M, Taverna E, Morlacchi E, Rosa P, Clementi F, Sher E. Transient translocation of N-type calcium channels from secretory granules to the cell surface. Ann N Y Acad Sci 1998; 841:119-21. [PMID: 9668231 DOI: 10.1111/j.1749-6632.1998.tb10919.x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Affiliation(s)
- M Passafaro
- CNR Institute of Biotechnology Applied to Pharmacology, Roccelletta di Borgia (CZ), Italy
| | | | | | | | | | | |
Collapse
|
31
|
Lang B, Waterman S, Pinto A, Jones D, Moss F, Boot J, Brust P, Williams M, Stauderman K, Harpold M, Motomura M, Moll JW, Vincent A, Newsom-Davis J. The role of autoantibodies in Lambert-Eaton myasthenic syndrome. Ann N Y Acad Sci 1998; 841:596-605. [PMID: 9668304 DOI: 10.1111/j.1749-6632.1998.tb10992.x] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Affiliation(s)
- B Lang
- Institute of Molecular Medicine, University of Oxford, United Kingdom
| | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
32
|
Satoh Y, Hirashima N, Tokumaru H, Takahashi MP, Kang J, Viglione MP, Kim YI, Kirino Y. Lambert-Eaton syndrome antibodies inhibit acetylcholine release and P/Q-type Ca2+ channels in electric ray nerve endings. J Physiol 1998; 508 ( Pt 2):427-38. [PMID: 9508807 PMCID: PMC2230882 DOI: 10.1111/j.1469-7793.1998.427bq.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
1. The types of voltage-dependent calcium channels (VDCCs) present in the cholinergic terminals isolated from the electric organ of the ray, Narke japonica, were characterized on the basis of their pharmacological sensitivity to specific antagonists. Inhibition of these channel types by autoantibodies from patients with the Lambert-Eaton syndrome (LES) was then studied to determine the specificity of the pathogenic IgG. 2. In normal untreated synaptosomal preparations, maximal doses of N- and P and/or Q-type Ca2+ channel antagonists, omega-conotoxin GVIA and omega-agatoxin IVA, inhibited depolarization-evoked ACh release by 47 % and 43 %, respectively. Calciseptine, an L-type VDCC antagonist, caused a 20 % reduction in the release. This indicates that the exocytotic release process is predominantly mediated by N- and P/Q-type VDCCs. 3. LES IgG or sera caused an inhibition of ACh release by 39-45 % in comparison with the control antibody-treated preparations. The ionomycin-induced ACh release, however, was not altered by the antibodies. Additionally, the same LES antibodies inhibited whole-cell calcium currents (ICa) in bovine adrenal chromaffin cells. Thus, the pathogenic antibodies exert their action on VDCCs present in the synaptosomes. 4. The efficacy of three Ca2+ channel antagonists in blocking ACh release was determined in preparations pretreated with LES IgG. omega-Agatoxin IVA produced only an additional 3-5 % reduction in release beyond that obtained with LES antibodies. Despite the pretreatment with LES IgG, omega-conotoxin GVIA and calciseptine inhibited the release to nearly their control levels. 5. These results indicate that LES antibodies mainly downregulate P/Q-type Ca2+ channels which contribute to presynaptic transmitter release from the cholinergic nerve terminals of electric organ. 6. The present findings are consistent with the hypothesis that P/Q-type VDCCs at the neuromuscular junction are the target of LES antibodies and that their inhibition by the antibodies produces the characteristic neuromuscular defect in this disease.
Collapse
Affiliation(s)
- Y Satoh
- School of Pharmaceutical Sciences, The University of Tokyo, Bunkyo-ku, Tokyo 113, Japan
| | | | | | | | | | | | | | | |
Collapse
|
33
|
Miles J, Charles P, Riches P. A review of methods available for the identification of both organ-specific and non-organ-specific autoantibodies. Ann Clin Biochem 1998; 35 ( Pt 1):19-47. [PMID: 9463737 DOI: 10.1177/000456329803500104] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Affiliation(s)
- J Miles
- Protein Reference and Immunopathology Unit, St George's Hospital Medical School, London, UK
| | | | | |
Collapse
|
34
|
Andjus PR, Stevic-Marinkovic Z, Cherubini E. Immunoglobulins from motoneurone disease patients enhance glutamate release from rat hippocampal neurones in culture. J Physiol 1997; 504 ( Pt 1):103-12. [PMID: 9350622 PMCID: PMC1159940 DOI: 10.1111/j.1469-7793.1997.103bf.x] [Citation(s) in RCA: 51] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
1. The whole-cell configuration of the patch-clamp technique was used to study the effects of immunoglobulins (IgGs) from patients affected by amyotrophic lateral sclerosis (ALS) on spontaneous glutamatergic currents in rat hippocampal cells in culture. 2. Focal application of ALS IgGs (100 micrograms ml-1) to hippocampal cells induced a rise in frequency but not in amplitude of spontaneous excitatory postsynaptic currents (SEPSC) which outlasted the period of IgG application. The mean frequency ratio (ALS over control) was 3.2 +/- 0.6 (n = 19). No changes in frequency or amplitude of SEPSCs were observed after treatment with IgGs obtained from healthy donors (n = 5) or from patients with Alzheimer's disease (n = 4). 3. ALS IgGs also increased the frequency (by a factor of 2.0 +/- 0.3) but not the amplitude of miniature excitatory postsynaptic currents (mEPSC) recorded in the presence of TTX (n = 19). A rise in frequency of mEPSC was also seen in cells superfused with a calcium-free solution (n = 4). 4. In the presence of TTX, ALS IgGs did not modify the amplitude or the shape of currents evoked by AMPA (100 microM), recorded at a holding potential of -50 mV. 5. It is concluded that ALS IgGs enhance both SEPSCs and mEPSCs through a presynaptic type of action. The excessive release of glutamate from nerve endings may be the cause of motoneurone death in ALS patients.
Collapse
Affiliation(s)
- P R Andjus
- Biophysics Sector, International School for Advanced Studies (SISSA), Trieste, Italy
| | | | | |
Collapse
|
35
|
Muchnik S, Losavio AS, Vidal A, Cura L, Mazia C. Long-term follow-up of Lambert-Eaton syndrome treated with intravenous immunoglobulin. Muscle Nerve 1997; 20:674-8. [PMID: 9149073 DOI: 10.1002/(sici)1097-4598(199706)20:6<674::aid-mus3>3.0.co;2-5] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Recent reports have shown that patients with Lambert-Eaton myasthenic syndrome (LEMS) improve transiently after high-dose intravenous immunoglobulin (IVIG) administration. Information about the usefulness of IVIG for long-term treatment is rather scanty. Our findings demonstrate the efficacy of monthly IVIG courses at a dose of 0.4 g/kg/day for 5 days, in a 41-year-old patient with LEMS without detectable malignancy. Improvement in limb strength, peak expiratory flow rate, and electrophysiological parameters, as well as clinical signs following IVIG, was evident as early as 7 days after the first course and is still maintained at 24-months follow-up.
Collapse
Affiliation(s)
- S Muchnik
- Instituto de Investigaciones Médicas Alfredo Lanari, Universidad de Buenos Aires, Argentina
| | | | | | | | | |
Collapse
|
36
|
Affiliation(s)
- M M Rich
- Department of Neurology, University of Pennsylvania School of Medicine, Philadelphia 19104, USA
| | | | | |
Collapse
|
37
|
Motomura M, Lang B, Johnston I, Palace J, Vincent A, Newsom-Davis J. Incidence of serum anti-P/O-type and anti-N-type calcium channel autoantibodies in the Lambert-Eaton myasthenic syndrome. J Neurol Sci 1997; 147:35-42. [PMID: 9094058 DOI: 10.1016/s0022-510x(96)05303-8] [Citation(s) in RCA: 187] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The Lambert-Eaton myasthenic syndrome (LEMS) is an autoimmune disease in which autoantibodies are directed against voltage-gated calcium channels (VGCCs) at presynaptic nerve terminals. We first demonstrated the presence of P/Q-type and N-type VGCCs in digitonin extracts prepared from human and rabbit cerebellum using the specific ligands 125I-omega-conotoxin MVIIC (125I-omega-CmTx) and 125I-omega-conotoxin GVIA (125I-omega-CgTx), respectively. We then tested sera from 72 LEMS patients' 25 with proven small cell lung cancer (SCLC) and 66 healthy or other neurological, SCLC or autoimmune disease controls in an immunoprecipitation assay using 125I-omega-CmTx-labelled (P/Q-type) VGCCs in human cerebellar extract. Sixty-six of 72 LEMS serum samples (91.7%) were positive for the presence of VGCC antibodies, as defined as a titre greater than 3 standard deviations above the mean for the healthy controls (n = 22). Rabbit cerebellar extract as antigen gave similar results (r = 0.94, P < 0.001, n = 30). By contrast, only 24/72 (33%) LEMS sera were positive in the assay for anti-N-type VGCC antibodies using 125I-omega-CgTx. All these 24 were also positive in the 125I-omega-CmTx assay. All healthy and disease control sera were negative in both assays. The anti-P/Q-type VGCC antibody titres did not correlate with an electrophysiological index of disease severity across individuals; however, longitudinal studies in a LEMS patient with SCLC receiving chemotherapy, and in a non-SCLC LEMS patient receiving immunosuppressive therapy showed an inverse relation between antibody titre and disease severity. These results support the view that anti-P/Q-type VGCC antibodies are implicated in the motor disorder in LEMS, and show that the omega-CmTx radioimmunoassay is a highly specific and sensitive means of detecting them.
Collapse
Affiliation(s)
- M Motomura
- Institute of Molecular Medicine, University of Oxford, John Radcliffe Hospital, UK
| | | | | | | | | | | |
Collapse
|
38
|
Passafaro M, Rosa P, Sala C, Clementi F, Sher E. N-type Ca2+ channels are present in secretory granules and are transiently translocated to the plasma membrane during regulated exocytosis. J Biol Chem 1996; 271:30096-104. [PMID: 8939958 DOI: 10.1074/jbc.271.47.30096] [Citation(s) in RCA: 52] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
An intracellular pool of N-type voltage-operated calcium channels has recently been described in different neuronal cell lines. We have now further characterized the intracellular pool of N-type calcium channels in both IMR32 human neuroblastoma and PC12 rat pheochromocytoma cells. Intracellular N-type calcium channels were found to be accumulated in subcellular fractions where the chromogranin B-containing secretory granules were also enriched. 125I-omega-Conotoxin GVIA binding assays on fixed and permeabilized cells revealed that intracellular N-type calcium channels translocate to the plasma membrane in cells exposed to secretagogues (KCl, ionomycin, and phorbol esters). The kinetics, Ca2+ and protein kinase C dependence, and brefeldin A insensitivity of N-type calcium channels translocation were similar to the regulated release of chromogranin B, while no correlation was found with the constitutive secretion of a heparan sulfate proteoglycan. A PC12 subclone deficient in the regulated but not in the constitutive pathway of secretion had a small intracellular pool of N-type calcium channels, and no secretagogue-induced translocation occurred in these cells. Calcium channel translocation was accompanied by a stronger response of Fura-2-loaded cells to depolarizing stimuli, suggesting that the newly inserted channels are functional.
Collapse
Affiliation(s)
- M Passafaro
- CNR Institute of Biotechnologies Applied to Pharmacology, 88021 Roccelletta di Borgia (CZ), Italy.
| | | | | | | | | |
Collapse
|
39
|
Arsac C, Raymond C, Martin-Moutot N, Dargent B, Couraud F, Pouget J, Seagar M. Immunoassays fail to detect antibodies against neuronal calcium channels in amyotrophic lateral sclerosis serum. Ann Neurol 1996; 40:695-700. [PMID: 8957009 DOI: 10.1002/ana.410400504] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Recent studies suggested that autoantibodies that bind to voltage-dependent calcium channels and activate calcium entry may play a role in the progressive degeneration of motoneurons in sporadic amyotrophic lateral sclerosis. Immunoassays were performed to assess autoantibody titer in patients with amyotrophic lateral sclerosis or Lambert-Eaton myasthenic syndrome, a disease in which the presence of anti-calcium channel antibodies is well documented. Based on immunoprecipitation assays for antibodies against N-type calcium channels, only 8% (2/25) of amyotrophic lateral sclerosis patients had marginally positive titers, whereas 58% (18/31) of patients with Lambert-Eaton myasthenic syndrome had positive titers. Enzyme-linked immunosorbent assays with purified neuronal N-type calcium channels revealed immunoreactivity in 2 of 25 amyotrophic lateral sclerosis sera and 12 of 31 Lambert-Eaton myasthenic syndrome sera, which is not compatible with suggestions that enzyme-linked immunosorbent assay is a more sensitive technique for the detection of autoantibodies in amyotrophic lateral sclerosis. Furthermore, based on immunoprecipitation assays, amyotrophic lateral sclerosis sera were totally negative for antibodies against L-type calcium channels from skeletal muscle or brain. These data do not support the hypothesis that an autoimmune response against calcium channels plays a primary role in amyotrophic lateral sclerosis.
Collapse
Affiliation(s)
- C Arsac
- INSERM U374, Institut Jean Roche, Faculté de Médecine Secteur Nord, Marseille, France
| | | | | | | | | | | | | |
Collapse
|
40
|
Honnorat J, Antoine JC, Derrington E, Aguera M, Belin MF. Antibodies to a subpopulation of glial cells and a 66 kDa developmental protein in patients with paraneoplastic neurological syndromes. J Neurol Neurosurg Psychiatry 1996; 61:270-8. [PMID: 8795598 PMCID: PMC486550 DOI: 10.1136/jnnp.61.3.270] [Citation(s) in RCA: 151] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
BACKGROUND Paraneoplastic neurological syndromes (PNS) are inflammatory disorders that probably depend on autoimmune processes. Several autoantibodies (anti-Hu, anti-Ri, and anti-Yo) have been characterised in PNS and proved to be helpful in the diagnosis. However, these do not account for all the cases and the possibility that other types of antibodies could be detected was investigated. METHODS AND RESULTS Of 45 patients with PNS whose serum was probed on paraformaldehyde fixed rat brain sections, 11 patients were identified whose serum samples recognised a cytoplasmic antigen in a subpopulation of glial cells in the white matter of adult rat brainstem, cerebellum, and spinal cord that were double labelled with a monoclonal antibody specific for oligodendrocytes. All serum samples reacted with a 66 kDa protein of newborn rat brain on western blot analysis. These antibodies were designated as anti-CV2 antibodies. Only one of the 11 patients had one of the well characterised autoantibodies (anti-Hu). Five patients had cerebellar degeneration, three had limbic encephalitis, two had encephalomyelitis, and one had Lambert-Eaton myasthenic syndrome. The tumours were small cell lung cancer or undifferentiated mediastinal cancer in seven patients, uterine sarcoma in two, and malignant thymoma in two. Among 1061 control serum samples, only two patients had anti-CV2 antibodies. One had small cell lung cancer and the other malignant thymoma. CONCLUSIONS The detection of anti-CV2 antibodies in patients with neurological disorders should be considered as an indication of the presence of an occult cancer.
Collapse
Affiliation(s)
- J Honnorat
- INSERM U 433, department of Neuropathology, Hôpital Neurologique, Lyon, France
| | | | | | | | | |
Collapse
|
41
|
Suenaga A, Shirabe S, Nakamura T, Motomura M, Tsujihata M, Matsuo H, Kataoka Y, Niwa M, Itoh M, Nagataki S. Specificity of autoantibodies react with omega-conotoxin MVIIC-sensitive calcium channel in Lambert-Eaton myasthenic syndrome. Muscle Nerve 1996; 19:1166-8. [PMID: 8761275 DOI: 10.1002/(sici)1097-4598(199609)19:9<1166::aid-mus13>3.0.co;2-t] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Affiliation(s)
- A Suenaga
- First Department of Internal Medicine, Nagasaki University School of Medicine, Japan
| | | | | | | | | | | | | | | | | | | |
Collapse
|
42
|
Magnelli V, Grassi C, Parlatore E, Sher E, Carbone E. Down-regulation of non-L-, non-N-type (Q-like) Ca2+ channels by Lambert-Eaton myasthenic syndrome (LEMS) antibodies in rat insulinoma RINm5F cells. FEBS Lett 1996; 387:47-52. [PMID: 8654565 DOI: 10.1016/0014-5793(96)00465-6] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
The action exerted on non-L-, non-N-type (Q-like) Ca 2+ channels by immunoglobulins G (IgGs) obtained from two patients with Lambert-Eaton myasthenic syndrome (LEMS) was investigated in the rat insulinoma RINm5F cell line. LEMS IgGs reduced by 30-36% the whole-cell Ba2+ currents through Q-like Ca2+ channels at +10 mV without significantly modifying their voltage dependence and activation kinetics. Single- and multiple-channel recordings in cell-attached and outside-out patches of cells treated with LEMS IgGs showed no significant changes of the channel elementary properties but rather a decreased number of active channels per patch. This suggests that Q-like current depression by LEMS autoantibodies is mostly due to a down-regulation of functioning Ca2+ channels. In agreement with previous observations, LEMS IgGs also reduced by 20-33% the dihydropyridine-sensitive (L-type) Ba2+ current. The suggested down-regulation of Q-like channels by LEMS IgGs in RINm5F cells may have a functional correlation with the depressive action of LEMS autoantibodies on the P/Q-type Ca2+ channels controlling acetylcholine release from mammalian neuromuscular junctions.
Collapse
Affiliation(s)
- V Magnelli
- Department of Neuroscience, Corso Raffaello 30, Turin, Italy
| | | | | | | | | |
Collapse
|
43
|
Dalmau J, Posner JB. Neurological paraneoplastic syndromes. SPRINGER SEMINARS IN IMMUNOPATHOLOGY 1996; 18:85-95. [PMID: 8984682 DOI: 10.1007/bf00792611] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Affiliation(s)
- J Dalmau
- Department of Neurology, Memorial Sloan-Kettering Cancer Center, New York, NY, 10021, USA
| | | |
Collapse
|
44
|
Takamori M, Takahashi M, Yasukawa Y, Iwasa K, Nemoto Y, Suenaga A, Nagataki S, Nakamura T. Antibodies to recombinant synaptotagmin and calcium channel subtypes in Lambert-Eaton myasthenic syndrome. J Neurol Sci 1995; 133:95-101. [PMID: 8583238 DOI: 10.1016/0022-510x(95)00162-u] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Several proteins have been postulated as possible targets of immune attack in Lambert-Eaton myasthenic syndrome (LEMS). Heterogeneity of autoantibodies in sera from 20 LEMS patients was studied by comparing their reactivity to synaptotagmin, a synaptic vesicle protein, and voltage-gated calcium channels (VGCCs). Six patients' sera (1 with small cell lung carcinoma (SCLC)) contained antibodies specifically recognizing the recombinant synaptotagmin on immunoblots. Thirteen (11 with SCLC) and 16 (11 with SCLC and 1 with poorly differentiated cell carcinoma in the lung) patients' sera immunoprecipitated omega-conotoxin GVIA-labeled N-type and omega-conotoxin MVIIC-labeled Q-type VGCCs, respectively. Three of 6 synaptotagmin-positive sera had cross-reactivity with N and/or Q subtypes of VGCC; the remaining 3 showed no cross-reactivity with VGCCs. Results indicate that LEMS sera are heterogeneous in the spectrum of containing antibodies, and suggest that this heterogeneity reflects the immune response to various synaptic proteins including not only multiple VGCCs but also synaptosecretory complex proteins.
Collapse
Affiliation(s)
- M Takamori
- Department of Neurology, Kanazawa University School of Medicine, Ishikawa-ken, Japan
| | | | | | | | | | | | | | | |
Collapse
|
45
|
Abstract
Neuromuscular dysfunction in patients with known or suspected malignancy has three basic etiologies: (1) a direct effect of the neoplasm, either by compression or infiltration; (2) a "remote," or paraneoplastic, effect of cancer; or (3) a side effect of anticancer treatment, radiation or chemotherapy. A variety of clinical features or syndromes are due to damage either at the level of the neuron (anterior horn cell or dorsal root ganglion neuron), nerve root(s), brachial or lumbosacral plexus, peripheral nerve (motor, sensory, and/or autonomic), neuromuscular junction, or muscle. A complex clinical picture evolves when dysfunction in due to more than one cause at more than one anatomical site.
Collapse
Affiliation(s)
- J P Stübgen
- Department of Neurology, Memorial Sloan-Kettering Cancer Center, New York, NY 10021, USA
| |
Collapse
|
46
|
Lennon VA, Kryzer TJ, Griesmann GE, O'Suilleabhain PE, Windebank AJ, Woppmann A, Miljanich GP, Lambert EH. Calcium-channel antibodies in the Lambert-Eaton syndrome and other paraneoplastic syndromes. N Engl J Med 1995; 332:1467-74. [PMID: 7739683 DOI: 10.1056/nejm199506013322203] [Citation(s) in RCA: 446] [Impact Index Per Article: 15.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
BACKGROUND Voltage-gated calcium channels in small-cell lung carcinomas may initiate autoimmunity in the paraneoplastic neuromuscular disorder Lambert-Eaton syndrome. The calcium-channel subtype that is responsible is not known. METHODS We compared the effects of antagonists of L-type, N-type, and P/Q-type neuronal calcium channels on the depolarization-dependent influx of calcium-45 in cultured carcinoma cells. Serum samples from patients with various disorders were tested for reactivity with P/Q-type channels solubilized from carcinoma and cerebellar membranes and N-type channels from cerebral cortex. RESULTS P/Q-type calcium-channel antagonists were the most potent inhibitors of depolarization-induced 45Ca influx in cultured small-cell carcinoma cell lines. Anti-P/Q-type calcium-channel antibodies were found in serum from all 32 patients with Lambert-Eaton syndrome and a diagnosis of cancer and in 91 percent of the 33 patients with Lambert-Eaton syndrome without cancer. Anti-N-type calcium-channel antibodies were found in 49 percent of the 65 patients with the Lambert-Eaton Syndrome. Lower titers of anti-P/Q-type and anti-N-type calcium-channel antibodies were found in 54 percent of 70 patients with a paraneoplastic encephalomyeloneuropathic complication of lung, ovarian, or breast carcinoma, 24 percent of 90 patients with cancer but no evident neurologic complications, 23 percent of 78 patients with sporadic amyotrophic lateral sclerosis, and less than 3 percent of 69 patients with myasthenia gravis, epilepsy, or scleroderma. CONCLUSIONS The high frequency of P/Q-type calcium-channel antibodies found in patients with Lambert-Eaton syndrome implies that antibodies of this specificity have a role in the presynaptic pathophysiology of this disorder.
Collapse
Affiliation(s)
- V A Lennon
- Department of Immunology, Mayo Clinic, Rochester, MN 55905, USA
| | | | | | | | | | | | | | | |
Collapse
|
47
|
Martin-Moutot N, Lang B, Newsom-Davis J, Seagar M. Binding of Lambert-Eaton myasthenic syndrome IgG to synaptosomal proteins does not correlate with an inhibition of calcium uptake. Neurosci Lett 1995; 187:115-8. [PMID: 7783957 DOI: 10.1016/0304-3940(95)11350-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
The immunochemical and functional properties of IgG fractions from patients with Lambert-Eaton myasthenic syndrome (LEMS) were examined in chick and rat synaptosomes. LEMS IgG immunoprecipitated 125I-omega conotoxin GVIA (125I-omega CgTx) labeled N-type calcium channels solubilized from both tissues, and reacted with a 65 kDa protein band in immunoblots of rat synaptosomes. Depolarization-induced 45Ca2+ influx into chick synaptosomes was partially inhibited by omega CgTx, whereas influx into rat synaptosomes was insensitive to omega CgTx. No effect of LEMS sera or IgG on 45Ca2+ uptake was apparent in either preparation.
Collapse
Affiliation(s)
- N Martin-Moutot
- Neurobiologie des canaux ioniques, INSERM U 374, Institut Jean Roche, Faculté de Médecine Nord, Marseille, France
| | | | | | | |
Collapse
|
48
|
Heidenreich F, Schober R, Brinck U, Hartung HP. Multiple paraneoplastic syndromes in a patient with antibodies to neuronal nucleoproteins (anti-Hu). J Neurol 1995; 242:210-6. [PMID: 7798119 DOI: 10.1007/bf00919593] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
We report the clinical and autopsy studies of a patient with an unusual combination of multiple paraneoplastic neurological syndromes in association with antibodies to a 35-40 kDa neuronal nucleo-protein (anti-Hu). Neurological disease preceded the detection of a small cell carcinoma of the lung. The patient had combined sensory and motor neuronopathy or neuropathy, cerebellar degeneration, brain-stem and limbic encephalitis, and clinical evidence of the Lambert-Eaton myasthenic syndrome and gastrointestinal pseudo-obstruction of paraneoplastic origin.
Collapse
Affiliation(s)
- F Heidenreich
- Neurologische Klinik, Medizinische Hochschule Hannover, Germany
| | | | | | | |
Collapse
|
49
|
Affiliation(s)
- J Bauer
- Centre Pluridisciplinaire d'Oncologie, Centre Hospitalier Universitaire Vaudois, Lausanne, Switzerland
| | | | | |
Collapse
|
50
|
Mosier DR, Baldelli P, Delbono O, Smith RG, Alexianu ME, Appel SH, Stefani E. Amyotrophic lateral sclerosis immunoglobulins increase Ca2+ currents in a motoneuron cell line. Ann Neurol 1995; 37:102-9. [PMID: 7818241 DOI: 10.1002/ana.410370119] [Citation(s) in RCA: 52] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
The sporadic form of amyotrophic lateral sclerosis (ALS) is an idiopathic and eventually lethal disorder causing progressive degeneration of cortical and spinal motoneurons. Recent studies have shown that the majority of patients with sporadic ALS have serum antibodies that bind to purified L-type voltage-gated calcium channels and that antibody titer correlates with the rate of disease progression. Furthermore, antibodies purified from ALS patient sera have been found to alter the physiologic function of voltage-gated calcium channels in nonmotoneuron cell types. Using whole-cell patch-clamp techniques, immunoglobulins purified from sera of 5 of 6 patients with sporadic ALS are now shown to increase calcium currents in a hybrid motoneuron cell line, VSC4.1. These calcium currents are blocked by the polyamine funnel-web spider toxin FTX, which has previously been shown to block Ca2+ currents and evoked transmitter release at mammalian motoneuron terminals. These data provide additional evidence linking ALS to an autoimmune process and suggest that antibody-induced increases in calcium entry through voltage-gated calcium channels may occur in motoneurons in this disease, with possible deleterious effects in susceptible neurons.
Collapse
Affiliation(s)
- D R Mosier
- Department of Neurology, Baylor College of Medicine, Houston, TX 77030
| | | | | | | | | | | | | |
Collapse
|