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Taraschenko O, Fox HS, Heliso P, Al-Saleem F, Dessain S, Kim WY, Samuelson MM, Dingledine R. Memory loss and aberrant neurogenesis in mice exposed to patient anti-N-methyl-d-aspartate receptor antibodies. Exp Neurol 2024; 378:114838. [PMID: 38801989 DOI: 10.1016/j.expneurol.2024.114838] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2024] [Revised: 05/14/2024] [Accepted: 05/24/2024] [Indexed: 05/29/2024]
Abstract
OBJECTIVE Anti-N-methyl-d-aspartate receptor (anti-NMDAR) encephalitis results in chronic epilepsy and permanent cognitive impairment. One of the possible causes of cognitive impairment in anti-NMDAR could be aberrant neurogenesis, an established contributor to memory loss in idiopathic drug-resistant epilepsy. We developed a mouse model of anti-NMDAR encephalitis and showed that mice exposed to patient anti-NMDAR antibodies for 2 weeks developed seizures and memory loss. In the present study, we assessed the delayed effects of patient-derived antibodies on cognitive phenotype and examined the corresponding changes in hippocampal neurogenesis. METHODS Monoclonal anti-NMDAR antibodies or control antibodies were continuously infused into the lateral ventricle of male C56BL/6J mice (8-12 weeks) via osmotic minipumps for 2 weeks. The motor and anxiety phenotypes were assessed using the open field paradigm, and hippocampal memory and learning were assessed using the object location, Y maze, and Barnes maze paradigms during weeks 1 and 3-4 of antibody washout. The numbers of newly matured granule neurons (Prox-1+) and immature progenitor cells (DCX+) as well as their spatial distribution within the hippocampus were assessed at these time points. Bromodeoxyuridine (BrdU, 50 mg/kg, i.p., daily) was injected on days 2-12 of the infusion, and proliferating cell immunoreactivity was compared in antibody-treated mice and control mice during week 4 of the washout. RESULTS Mice infused with anti-NMDAR antibodies demonstrated spatial memory impairment during week 1 of antibody washout (p = 0.02, t-test; n = 9-11). Histological analysis of hippocampal sections from these mice revealed an increased ectopic displacement of Prox-1+ cells in the dentate hilus compared to the control-antibody-treated mice (p = 0.01; t-test). Mice exposed to anti-NMDAR antibodies also had an impairment of spatial memory and learning during weeks 3-4 of antibody washout (object location: p = 0.009; t-test; Y maze: p = 0.006, t-test; Barnes maze: p = 0.008, ANOVA; n = 8-10). These mice showed increased ratios of the low proliferating (bright) to fast proliferating (faint) BrdU+ cell counts and decreased number of DCX+ cells in the hippocampal dentate gyrus (p = 0.006 and p = 0.04, respectively; t-tests) suggesting ectopic migration and delayed cell proliferation. SIGNIFICANCE These findings suggest that memory and learning impairments induced by patient anti-NMDAR antibodies are sustained upon removal of antibodies and are accompanied by aberrant hippocampal neurogenesis. Interventions directed at the manipulation of neuronal plasticity in patients with encephalitis and cognitive loss may be protective and therapeutically relevant.
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Affiliation(s)
- Olga Taraschenko
- Department of Neurological Sciences, Division of Epilepsy, University of Nebraska Medical Center, Omaha, NE, United States of America.
| | - Howard S Fox
- Department of Neurological Sciences, Division of Epilepsy, University of Nebraska Medical Center, Omaha, NE, United States of America
| | - Priscilla Heliso
- Department of Neurological Sciences, Division of Epilepsy, University of Nebraska Medical Center, Omaha, NE, United States of America
| | - Fetweh Al-Saleem
- Lankenau Institute for Medical Research, Wynnewood, PA, United States of America
| | - Scott Dessain
- Lankenau Institute for Medical Research, Wynnewood, PA, United States of America
| | - Woo-Yang Kim
- Department of Biological Sciences, Kent State University, Kent, OH, United States of America
| | - Mystera M Samuelson
- Department of Environmental, Agricultural and Occupational Health, University of Nebraska Medical Center, Omaha, NE, United States of America
| | - Raymond Dingledine
- Department of Pharmacology and Chemical Biology, Emory University School of Medicine, Atlanta, GA, United States of America
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Taraschenko O, Fox HS, Eldridge E, Heliso P, Al-Saleem F, Dessain S, Casale G, Willcockson G, Anderson K, Wang W, Dingledine R. MyD88-mediated signaling is critical for the generation of seizure responses and cognitive impairment in a model of anti-N-methyl-D-aspartate receptor encephalitis. Epilepsia 2024; 65:1475-1487. [PMID: 38470097 PMCID: PMC11087204 DOI: 10.1111/epi.17931] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2023] [Revised: 02/11/2024] [Accepted: 02/12/2024] [Indexed: 03/13/2024]
Abstract
OBJECTIVE We previously demonstrated that interleukin-1 receptor-mediated immune activation contributes to seizure severity and memory loss in anti-N-methyl-D-aspartate receptor (NMDAR) encephalitis. In the present study, we assessed the role of the myeloid differentiation primary response gene 88 (MyD88), an adaptor protein in Toll-like receptor signaling, in the key phenotypic characteristics of anti-NMDAR encephalitis. METHODS Monoclonal anti-NMDAR antibodies or control antibodies were infused into the lateral ventricle of MyD88 knockout mice (MyD88-/-) and control C56BL/6J mice (wild type [WT]) via osmotic minipumps for 2 weeks. Seizure responses were measured by electroencephalography. Upon completion of the infusion, the motor, anxiety, and memory functions of the mice were assessed. Astrocytic (glial fibrillary acidic protein [GFAP]) and microglial (ionized calcium-binding adaptor molecule 1 [Iba-1]) activation and transcriptional activation for the principal inflammatory mediators involved in seizures were determined using immunohistochemistry and quantitative real-time polymerase chain reaction, respectively. RESULTS As shown before, 80% of WT mice infused with anti-NMDAR antibodies (n = 10) developed seizures (median = 11, interquartile range [IQR] = 3-25 in 2 weeks). In contrast, only three of 14 MyD88-/- mice (21.4%) had seizures (0, IQR = 0-.25, p = .01). The WT mice treated with antibodies also developed memory loss in the novel object recognition test, whereas such memory deficits were not apparent in MyD88-/- mice treated with anti-NMDAR antibodies (p = .03) or control antibodies (p = .04). Furthermore, in contrast to the WT mice exposed to anti-NMDAR antibodies, the MyD88-/- mice had a significantly lower induction of chemokine (C-C motif) ligand 2 (CCL2) in the hippocampus (p = .0001, Sidak tests). There were no significant changes in the expression of GFAP and Iba-1 in the MyD88-/- mice treated with anti-NMDAR or control antibodies. SIGNIFICANCE These findings suggest that MyD88-mediated signaling contributes to the seizure and memory phenotype in anti-NMDAR encephalitis and that CCL2 activation may participate in the expression of these features. The removal of MyD88 inflammation may be protective and therapeutically relevant.
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Affiliation(s)
- Olga Taraschenko
- Department of Neurological Sciences, Division of Epilepsy, University of Nebraska Medical Center, Omaha, NE
| | - Howard S. Fox
- Department of Neurological Sciences, Division of Epilepsy, University of Nebraska Medical Center, Omaha, NE
| | - Ember Eldridge
- Department of Neurological Sciences, Division of Epilepsy, University of Nebraska Medical Center, Omaha, NE
| | - Priscilla Heliso
- Department of Neurological Sciences, Division of Epilepsy, University of Nebraska Medical Center, Omaha, NE
| | | | - Scott Dessain
- Lankenau Institute for Medical Research, Wynnewood, PA
| | - George Casale
- Department of Surgery, Division of Vascular Surgery, University of Nebraska Medical Center, Omaha, NE
| | | | - Kayley Anderson
- Department of Neurological Sciences, Division of Epilepsy, University of Nebraska Medical Center, Omaha, NE
| | - Wenyi Wang
- Department of Pharmacology and Chemical Biology, Emory University School of Medicine, Atlanta, GA
| | - Raymond Dingledine
- Department of Pharmacology and Chemical Biology, Emory University School of Medicine, Atlanta, GA
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Qiao S, Li H, Cui C, Zhang C, Wang A, Jiang W, Zhang S. CSF Findings in Chinese Patients with NMDAR, LGI1 and GABABR Antibody-Associated Encephalitis. J Inflamm Res 2024; 17:1765-1776. [PMID: 38523682 PMCID: PMC10959177 DOI: 10.2147/jir.s383161] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2023] [Accepted: 02/01/2024] [Indexed: 03/26/2024] Open
Abstract
Purpose CSF inflammation in subtypes of antibody-defined autoimmune encephalitis (AE) ranges in intensity from moderate to severe. In a retrospective, cross-sectional study, we characterized CSF findings in Chinese patients with anti-N-methyl-D-aspartate receptor encephalitis (NMDAR-E), anti-leucine-rich glioma-inactivated 1 encephalitis (LGI1-E), and anti-gamma aminobutyric acid-B receptor encephalitis (GABABR-E). Patients and Methods The AE cases, including 102 NMDAR-E, 68 LGI1-E and 15 GABABR-E, were included. CSF inflammatory parameters consisted primarily of CSF leukocytes, oligoclonal bands (OCBs), and CSF/serum albumin ratios (QAlb). Ten serum cytokines were evaluated in order to classify AE subtypes. Results 88% of NMDAR-E, 80% of GABABR-E, and 51% of LGI1-E patients had aberrant CSF features. In NMDAR-E, the CSF leukocyte count, CSF protein concentration, and age-adjusted QAlb were significantly higher than in LGI1-E, but did not differ from GABABR-E. Blood-CSF barrier dysfunction was less common in NMDAR-E patients with >40 years old. On admission, inflammatory CSF response was more prevalent in NMDAR-E patients with a higher CASE score. With age <60 years, CSF inflammatory changes were less frequent in LGI1-E patients, but more common in GABABR-E patients. MCP-1, IL-10, IL-1β, and IL-4 were potential classifiers for NMDAR-E, LGI1-E, and GABABR-E, and correlated substantially with CSF leukocyte count and QAlb. Conclusion Subtype-specific patterns are formed by the various inflammatory CSF parameters in NMDAR-E, LGI1-E, and GABABR-E, and their correlation with disease severity, age, and disease duration. CSF inflammatory characteristics associated with MCP-1, IL-10, IL-1β, and IL-4 may be potential immunopathogeneses targeting markers for these AE subtypes.
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Affiliation(s)
- Shan Qiao
- Department of Neurology, the First Affiliated Hospital of Shandong First Medical University & Shandong Provincial Qianfoshan Hospital, Shandong First Medical University, Jinan, People’s Republic of China
- Department of Medical Genetics, School of Basic Medical Sciences, Cheeloo College of Medicine, Shandong University, Jinan, People’s Republic of China
| | - Haiyun Li
- Department of Geriatric Medicine, Qilu Hospital, Cheeloo College of Medicine, Shandong University, Jinan, People’s Republic of China
| | - Caisan Cui
- Department of Neurology, Qilu Hospital, Cheeloo College of Medicine, Shandong University, Jinan, People’s Republic of China
| | - Chong Zhang
- Department of Neurology, the First Affiliated Hospital of Shandong First Medical University & Shandong Provincial Qianfoshan Hospital, Shandong First Medical University, Jinan, People’s Republic of China
| | - Aihua Wang
- Department of Neurology, the First Affiliated Hospital of Shandong First Medical University & Shandong Provincial Qianfoshan Hospital, Shandong First Medical University, Jinan, People’s Republic of China
| | - Wenjing Jiang
- Department of Geriatric Medicine, Qilu Hospital, Cheeloo College of Medicine, Shandong University, Jinan, People’s Republic of China
| | - Shanchao Zhang
- Department of Neurology, the First Affiliated Hospital of Shandong First Medical University & Shandong Provincial Qianfoshan Hospital, Shandong First Medical University, Jinan, People’s Republic of China
- School of Medicine, Cheeloo College of Medicine, Shandong University, Jinan, People’s Republic of China
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Pişkin ŞA, Korkmaz HY, Ulusoy CA, Şanlı E, Küçükali CI, Onat F, Tüzün E, Çarçak N. Antibody induced seizure susceptibility and impaired cognitive performance in a passive transfer rat model of autoimmune encephalitis. Front Immunol 2023; 14:1268986. [PMID: 38035091 PMCID: PMC10684964 DOI: 10.3389/fimmu.2023.1268986] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2023] [Accepted: 10/30/2023] [Indexed: 12/02/2023] Open
Abstract
Objective Autoimmune encephalitis (AE) is a distinct neuro-immunological disorder associated with the production of autoantibodies against neuronal proteins responsible for pharmacoresistant seizures, cognitive decline and behavioral problems. To establish the causal link between leucine-rich glioma inactivated 1 (LGI1) antibody and seizures, we developed an in-vivo antibody-mediated AE rat model in which serum antibodies (IgG) obtained from blood samples of leucine-rich glioma inactivated 1 (LGI1) protein antibody (IgG) positive encephalitis patients were passively transferred into non-epileptic Wistar rats. Serum IgG of N-methyl-d-aspartate receptor (NMDAR) antibody positive patients were used as positive control since the pathogenicity of this antibody has been previously shown in animal models. Methods Total IgG obtained from the pooled sera of NMDAR and LGI1-IgG positive patients with epileptic seizures and healthy subjects was applied chronically every other day for 11 days into the cerebral lateral ventricle. Spontaneous seizure development was followed by electroencephalography. Behavioral tests for memory and locomotor activity were applied before and after the antibody infusions. Then, pentylenetetrazol (PTZ) was administered intraperitoneally to evaluate seizure susceptibility. Immunohistochemistry processed for assessment of hippocampal astrocyte proliferation and expression intensity of target NMDAR and LGI1 antigens. Results No spontaneous activity was observed during the antibody infusions. PTZ-induced seizure stage was significantly higher in the NMDAR-IgG and LGI1-IgG groups compared to control. Besides, memory deficits were observed in the NMDAR and LGI1-IgG groups. We observed enhanced astrocyte proliferation in NMDAR- and LGI1-IgG groups and reduced hippocampal NMDAR expression in NMDAR-IgG group. Significance These findings suggest that neuronal surface auto-antibody administration induces seizure susceptibility and disturbed cognitive performance in the passive transfer rat model of LGI1 AE, which could be a potential in-vivo model for understanding immune-mediated mechanisms underlying epileptogenesis and highlight the potential targets for immune-mediated seizures in AE patients.
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Affiliation(s)
- Şura Akat Pişkin
- Department of Pharmacology, Faculty of Pharmacy, Institute of Health Sciences, Istanbul University, Istanbul, Türkiye
| | - Hande Yüceer Korkmaz
- Department of Neuroscience, Aziz Sancar Institute of Experimental Medicine, Institute of Health Sciences, Istanbul University, Istanbul, Türkiye
| | - Canan Aysel Ulusoy
- Department of Neuroscience, Aziz Sancar Institute of Experimental Medicine, Istabul University, Istanbul, Türkiye
| | - Elif Şanlı
- Department of Neuroscience, Aziz Sancar Institute of Experimental Medicine, Institute of Health Sciences, Istanbul University, Istanbul, Türkiye
| | - Cem Ismail Küçükali
- Department of Neuroscience, Aziz Sancar Institute of Experimental Medicine, Istabul University, Istanbul, Türkiye
| | - Filiz Onat
- Department of Medical Pharmacology, Acibadem Mehmet Ali Aydinlar University Faculty of Medicine, Istanbul, Türkiye
- Deparment of Neuroscience, Acibadem Mehmet Ali Aydinlar University Health Sciences Institute, Istanbul, Türkiye
| | - Erdem Tüzün
- Department of Neuroscience, Aziz Sancar Institute of Experimental Medicine, Istabul University, Istanbul, Türkiye
| | - Nihan Çarçak
- Deparment of Neuroscience, Acibadem Mehmet Ali Aydinlar University Health Sciences Institute, Istanbul, Türkiye
- Department of Pharmacology, Faculty of Pharmacy, Istanbul University, Istanbul, Türkiye
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Qiao S, Sun Q, Li H, Yin J, Wang A, Zhang S. Abnormal DNA methylation analysis of leucine-rich glioma-inactivated 1 antibody encephalitis reveals novel methylation-driven genes related to prognostic and clinical features. Clin Epigenetics 2023; 15:139. [PMID: 37644514 PMCID: PMC10463459 DOI: 10.1186/s13148-023-01550-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2022] [Accepted: 08/09/2023] [Indexed: 08/31/2023] Open
Abstract
BACKGROUND Aberrant DNA methylation occurs commonly during pathogenesis of neuroimmunological diseases and is of clinical value in various encephalitis subtypes. However, knowledge of the impact of DNA methylation changes on pathogenesis of leucine-rich glioma-inactivated 1 (LGI1) antibody encephalitis remains limited. METHODS A total of 44 cytokines and 10 immune checkpoint moleculars (ICMs) in the serum of patients with LGI1 encephalitis and healthy donors (HDs) were measured to evaluate the association of them with clinical parameters. Genome-wide DNA methylation profiles were performed in peripheral blood mononuclear cell (PBMC) from LGI1 encephalitis patients and HDs using reduced representation bisulfite sequencing (RRBS) and validated for the methylation status by pyrosequencing. MicroRNA profiles were acquired in serum exosome by small RNA sequencing. Targeted cytokines expression was assessed at the presence or absence of miR-2467-5p in PBMCs and the culture media, and the binding of miR-2467-5p and its targeted genes was validated by luciferase assay. RESULTS There existed significant difference in 22 cytokines/chemokines and 6 ICMs between LGI1 encephalitis patients and HDs. Decreased PDCD1 with increased ICAM1 could predict unfavorable prognosis in one-year follow-up for LGI1 encephalitis patients. Fifteen of cytokines/chemokines and ICMs presented DNA-methylated changes in the promoter and gene body using RRBS in which five were verified as methylation status by pyrosequencing, and the methylation level of CSF3, CCL2, and ICAM1 was conversely associated with their expression in PBMCs. By combining RRBS data with exosome-derived microRNA sequencing, we found that hypomethylated-driven hsa-miR-2467-5p presented elevated expression in serum exosomes and PBMCs in LGI1 encephalitis. Mechanically, miR-2467-5p significantly induced reduced expression of CSF3 and PDCD1 by binding with their 3`UTR while enhanced CCL15 expression, but not significantly correlated with peripheral blood CD19 + B cell proportion of LGI1 encephalitis patients. CONCLUSIONS Our results provided convincing evidence for DNA methylation changes, microRNA profiles in serum exosome for LGI1 encephalitis, and we also identified several novel cytokines related to clinical features in which some represented epigenetic modification of methylated-driven pattern and microRNA modulation. Our study contributed to develop treatment for epigenetic pathogenesis in LGI1 encephalitis.
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Affiliation(s)
- Shan Qiao
- Department of Neurology, The First Affiliated Hospital of Shandong First Medical University and Shandong Provincial Qianfoshan Hospital, Shandong First Medical University, Jinan, China
- Department of Medical Genetics, School of Basic Medical Sciences, Cheeloo College of Medicine, Shandong University, Jinan, China
| | - Quanye Sun
- Research Center of Translational Medicine, Central Hospital Affiliated to Shandong First Medical University, Jinan, China
| | - Haiyun Li
- Department of Neurology, Qilu Hospital, Cheeloo College of Medicine, Shandong University, Jinan, China
| | - Jie Yin
- Department of Cardiology, The First Affiliated Hospital of Shandong First Medical University and Shandong Provincial Qianfoshan Hospital, Jinan, China
| | - Aihua Wang
- Department of Neurology, The First Affiliated Hospital of Shandong First Medical University and Shandong Provincial Qianfoshan Hospital, Shandong First Medical University, Jinan, China
| | - Shanchao Zhang
- Department of Neurology, The First Affiliated Hospital of Shandong First Medical University and Shandong Provincial Qianfoshan Hospital, Shandong First Medical University, Jinan, China.
- School of Medicine, Cheeloo College of Medicine, Shandong University, Jinan, China.
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Barker-Haliski M, Pitsch J, Galanopoulou AS, Köhling R. A companion to the preclinical common data elements for phenotyping seizures and epilepsy in rodent models. A report of the TASK3-WG1C: Phenotyping working group of the ILAE/AES joint translational task force. Epilepsia Open 2022. [PMID: 36461665 DOI: 10.1002/epi4.12676] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2021] [Accepted: 05/23/2022] [Indexed: 12/04/2022] Open
Abstract
Epilepsy is a heterogeneous disorder characterized by spontaneous seizures and behavioral comorbidities. The underlying mechanisms of seizures and epilepsy across various syndromes lead to diverse clinical presentation and features. Similarly, animal models of epilepsy arise from numerous dissimilar inciting events. Preclinical seizure and epilepsy models can be evoked through many different protocols, leaving the phenotypic reporting subject to diverse interpretations. Serendipity can also play an outsized role in uncovering novel drivers of seizures or epilepsy, with some investigators even stumbling into epilepsy research because of a new genetic cross or unintentional drug effect. The heightened emphasis on rigor and reproducibility in preclinical research, including that which is conducted for epilepsy, underscores the need for standardized phenotyping strategies. To address this goal as part of the TASK3-WG1C Working Group of the International League Against Epilepsy (ILAE)/American Epilepsy Society (AES) Joint Translational Task Force, we developed a case report form (CRF) to describe the common data elements (CDEs) necessary for the phenotyping of seizure-like behaviors in rodents. This companion manuscript describes the use of the proposed CDEs and CRF for the visual, behavioral phenotyping of seizure-like behaviors. These phenotyping CDEs and accompanying CRF can be used in parallel with video-electroencephalography (EEG) studies or as a first visual screen to determine whether a model manifests seizure-like behaviors before utilizing more specialized diagnostic tests, like video-EEG. Systematic logging of seizure-like behaviors may help identify models that could benefit from more specialized diagnostic tests to determine whether these are epileptic seizures, such as video-EEG.
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Affiliation(s)
- Melissa Barker-Haliski
- Department of Pharmacy, School of Pharmacy, University of Washington, Seattle, Washington, USA
| | - Julika Pitsch
- Department of Epileptology, University Hospital Bonn, Bonn, Germany
| | - Aristea S Galanopoulou
- Saul R. Korey Department of Neurology, Isabelle Rapin Division of Child Neurology, Laboratory of Developmental Epilepsy, Albert Einstein College of Medicine, Bronx, New York, USA
- Dominick P Purpura Department of Neuroscience, Isabelle Rapin Division of Child Neurology, Laboratory of Developmental Epilepsy, Albert Einstein College of Medicine, Bronx, New York, USA
| | - Rüdiger Köhling
- Oscar-Langendorff-Institut für Physiologie, Universitätsmedizin Rostock, Rostock, Germany
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Dean CA, Metzbower SR, Dessain SK, Blanpied TA, Benavides DR. Regulation of NMDA Receptor Signaling at Single Synapses by Human Anti-NMDA Receptor Antibodies. Front Mol Neurosci 2022; 15:940005. [PMID: 35966009 PMCID: PMC9371948 DOI: 10.3389/fnmol.2022.940005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2022] [Accepted: 06/21/2022] [Indexed: 11/13/2022] Open
Abstract
The NMDA receptor (NMDAR) subunit GluN1 is critical for receptor function and plays a pivotal role in synaptic plasticity. Mounting evidence has shown that pathogenic autoantibody targeting of the GluN1 subunit of NMDARs, as in anti-NMDAR encephalitis, leads to altered NMDAR trafficking and synaptic localization. However, the underlying signaling pathways affected by antibodies targeting the NMDAR remain to be fully delineated. It remains unclear whether patient antibodies influence synaptic transmission via direct effects on NMDAR channel function. Here, we show using short-term incubation that GluN1 antibodies derived from patients with anti-NMDAR encephalitis label synapses in mature hippocampal primary neuron culture. Miniature spontaneous calcium transients (mSCaTs) mediated via NMDARs at synaptic spines are not altered in pathogenic GluN1 antibody exposed conditions. Unexpectedly, spine-based and cell-based analyses yielded distinct results. In addition, we show that calcium does not accumulate in neuronal spines following brief exposure to pathogenic GluN1 antibodies. Together, these findings show that pathogenic antibodies targeting NMDARs, under these specific conditions, do not alter synaptic calcium influx following neurotransmitter release. This represents a novel investigation of the molecular effects of anti-NMDAR antibodies associated with autoimmune encephalitis.
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Affiliation(s)
- Charles A. Dean
- Department of Neurology, University of Maryland School of Medicine, Baltimore, MD, United States
| | - Sarah R. Metzbower
- Department of Physiology, University of Maryland School of Medicine, Baltimore, MD, United States
| | - Scott K. Dessain
- Lankenau Institute for Medical Research, Wynnewood, PA, United States
| | - Thomas A. Blanpied
- Department of Physiology, University of Maryland School of Medicine, Baltimore, MD, United States
| | - David R. Benavides
- Department of Neurology, University of Maryland School of Medicine, Baltimore, MD, United States
- *Correspondence: David R. Benavides,
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