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Papi C, Milano C, Spatola M. Mechanisms of autoimmune encephalitis. Curr Opin Neurol 2024; 37:305-315. [PMID: 38667756 DOI: 10.1097/wco.0000000000001270] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/30/2024]
Abstract
PURPOSE OF REVIEW To provide an overview of the pathogenic mechanisms involved in autoimmune encephalitides mediated by antibodies against neuronal surface antigens, with a focus on NMDAR and LGI1 encephalitis. RECENT FINDINGS In antibody-mediated encephalitides, binding of IgG antibodies to neuronal surface antigens results in different pathogenic effects depending on the type of antibody, IgG subclass and epitope specificity. NMDAR IgG1 antibodies cause crosslinking and internalization of the target, synaptic and brain circuitry alterations, as well as alterations of NMDAR expressing oligodendrocytes, suggesting a link with white matter lesions observed in MRI studies. LGI1 IgG4 antibodies, instead, induce neuronal dysfunction by disrupting the interaction with cognate proteins and altering AMPAR-mediated signaling. In-vitro findings have been corroborated by memory and behavioral changes in animal models obtained by passive transfer of patients' antibodies or active immunization. These models have been fundamental to identify targets for innovative therapeutic strategies, aimed at counteracting or preventing antibody effects, such as the use of soluble ephrin-B2, NMDAR modulators (e.g., pregnenolone, SGE-301) or chimeric autoantibody receptor T cells (CAART) in models of NMDAR encephalitis. SUMMARY A deep understanding of the pathogenic mechanisms underlying antibody-mediated encephalitides is crucial for the development of new therapeutic approaches targeting brain autoimmunity.
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Affiliation(s)
- Claudia Papi
- Department of Neuroscience, Catholic University of the Sacred Heart, Rome, Italy
- Fundació Recerca Biomedica Clinic - Institut d'Investigacions Biomèdiques August Pi i Sunyer (FRBC-IDIBAPS), Barcelona, Spain
| | - Chiara Milano
- Fundació Recerca Biomedica Clinic - Institut d'Investigacions Biomèdiques August Pi i Sunyer (FRBC-IDIBAPS), Barcelona, Spain
- Department of Clinical and Experimental Medicine, University of Pisa, Pisa, Italy
| | - Marianna Spatola
- Fundació Recerca Biomedica Clinic - Institut d'Investigacions Biomèdiques August Pi i Sunyer (FRBC-IDIBAPS), Barcelona, Spain
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Smith KM, Budhram A, Geis C, McKeon A, Steriade C, Stredny CM, Titulaer MJ, Britton JW. Autoimmune-associated seizure disorders. Epileptic Disord 2024. [PMID: 38818801 DOI: 10.1002/epd2.20231] [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: 01/24/2024] [Revised: 03/28/2024] [Accepted: 04/13/2024] [Indexed: 06/01/2024]
Abstract
With the discovery of an expanding number of neural autoantibodies, autoimmune etiologies of seizures have been increasingly recognized. Clinical phenotypes have been identified in association with specific underlying antibodies, allowing an earlier diagnosis. These phenotypes include faciobrachial dystonic seizures with LGI1 encephalitis, neuropsychiatric presentations associated with movement disorders and seizures in NMDA-receptor encephalitis, and chronic temporal lobe epilepsy in GAD65 neurologic autoimmunity. Prompt recognition of these disorders is important, as some of them are highly responsive to immunotherapy. The response to immunotherapy is highest in patients with encephalitis secondary to antibodies targeting cell surface synaptic antigens. However, the response is less effective in conditions involving antibodies binding intracellular antigens or in Rasmussen syndrome, which are predominantly mediated by cytotoxic T-cell processes that are associated with irreversible cellular destruction. Autoimmune encephalitides also may have a paraneoplastic etiology, further emphasizing the importance of recognizing these disorders. Finally, autoimmune processes and responses to novel immunotherapies have been reported in new-onset refractory status epilepticus (NORSE) and febrile infection-related epilepsy syndrome (FIRES), warranting their inclusion in any current review of autoimmune-associated seizure disorders.
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Affiliation(s)
- Kelsey M Smith
- Department of Neurology, Mayo Clinic, Rochester, Minnesota, USA
| | - Adrian Budhram
- Department of Clinical Neurological Sciences, London Health Sciences Centre, Western University, London, Ontario, Canada
- Department of Pathology and Laboratory Medicine, London Health Sciences Centre, Western University, London, Ontario, Canada
| | - Christian Geis
- Department of Neurology and Section Translational Neuroimmunology, Jena University Hospital, Jena, Germany
| | - Andrew McKeon
- Department of Neurology, Mayo Clinic, Rochester, Minnesota, USA
- Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, Minnesota, USA
| | - Claude Steriade
- Department of Neurology, New York University Langone Health, New York, New York, USA
| | - Coral M Stredny
- Department of Neurology, Boston Children's Hospital, Boston, Massachusetts, USA
| | - Maarten J Titulaer
- Department of Neurology, Erasmus University Medical Center, Rotterdam, the Netherlands
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Grünewald B, Wickel J, Hahn N, Rahmati V, Rupp H, Chung HY, Haselmann H, Strauss AS, Schmidl L, Hempel N, Grünewald L, Urbach A, Bauer M, Toyka KV, Blaess M, Claus RA, König R, Geis C. Targeted rescue of synaptic plasticity improves cognitive decline in sepsis-associated encephalopathy. Mol Ther 2024:S1525-0016(24)00301-0. [PMID: 38788710 DOI: 10.1016/j.ymthe.2024.05.001] [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: 09/01/2023] [Revised: 04/02/2024] [Accepted: 05/01/2024] [Indexed: 05/26/2024] Open
Abstract
Sepsis-associated encephalopathy (SAE) is a frequent complication of severe systemic infection resulting in delirium, premature death, and long-term cognitive impairment. We closely mimicked SAE in a murine peritoneal contamination and infection (PCI) model. We found long-lasting synaptic pathology in the hippocampus including defective long-term synaptic plasticity, reduction of mature neuronal dendritic spines, and severely affected excitatory neurotransmission. Genes related to synaptic signaling, including the gene for activity-regulated cytoskeleton-associated protein (Arc/Arg3.1) and members of the transcription-regulatory EGR gene family, were downregulated. At the protein level, ARC expression and mitogen-activated protein kinase signaling in the brain were affected. For targeted rescue we used adeno-associated virus-mediated overexpression of ARC in the hippocampus in vivo. This recovered defective synaptic plasticity and improved memory dysfunction. Using the enriched environment paradigm as a non-invasive rescue intervention, we found improvement of defective long-term potentiation, memory, and anxiety. The beneficial effects of an enriched environment were accompanied by an increase in brain-derived neurotrophic factor (BDNF) and ARC expression in the hippocampus, suggesting that activation of the BDNF-TrkB pathway leads to restoration of the PCI-induced reduction of ARC. Collectively, our findings identify synaptic pathomechanisms underlying SAE and provide a conceptual approach to target SAE-induced synaptic dysfunction with potential therapeutic applications to patients with SAE.
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Affiliation(s)
- Benedikt Grünewald
- Center for Sepsis Control and Care, Jena University Hospital, Am Klinikum 1, 07747 Jena, Germany; Section Translational Neuroimmunology, Department of Neurology, Jena University Hospital, Am Klinikum 1, 07747 Jena, Germany; Institute of Pathophysiology and Focus Program Translational Neuroscience (FTN), University Medical Center of the Johannes Gutenberg University Mainz, 55131 Mainz, Germany
| | - Jonathan Wickel
- Center for Sepsis Control and Care, Jena University Hospital, Am Klinikum 1, 07747 Jena, Germany; Section Translational Neuroimmunology, Department of Neurology, Jena University Hospital, Am Klinikum 1, 07747 Jena, Germany
| | - Nina Hahn
- Center for Sepsis Control and Care, Jena University Hospital, Am Klinikum 1, 07747 Jena, Germany; Section Translational Neuroimmunology, Department of Neurology, Jena University Hospital, Am Klinikum 1, 07747 Jena, Germany
| | - Vahid Rahmati
- Section Translational Neuroimmunology, Department of Neurology, Jena University Hospital, Am Klinikum 1, 07747 Jena, Germany
| | - Hanna Rupp
- Center for Sepsis Control and Care, Jena University Hospital, Am Klinikum 1, 07747 Jena, Germany; Section Translational Neuroimmunology, Department of Neurology, Jena University Hospital, Am Klinikum 1, 07747 Jena, Germany
| | - Ha-Yeun Chung
- Center for Sepsis Control and Care, Jena University Hospital, Am Klinikum 1, 07747 Jena, Germany; Section Translational Neuroimmunology, Department of Neurology, Jena University Hospital, Am Klinikum 1, 07747 Jena, Germany
| | - Holger Haselmann
- Center for Sepsis Control and Care, Jena University Hospital, Am Klinikum 1, 07747 Jena, Germany; Section Translational Neuroimmunology, Department of Neurology, Jena University Hospital, Am Klinikum 1, 07747 Jena, Germany
| | - Anja S Strauss
- Section Translational Neuroimmunology, Department of Neurology, Jena University Hospital, Am Klinikum 1, 07747 Jena, Germany
| | - Lars Schmidl
- Section Translational Neuroimmunology, Department of Neurology, Jena University Hospital, Am Klinikum 1, 07747 Jena, Germany
| | - Nina Hempel
- Section Translational Neuroimmunology, Department of Neurology, Jena University Hospital, Am Klinikum 1, 07747 Jena, Germany
| | - Lena Grünewald
- Department of Psychiatry, Psychosomatic Medicine and Psychotherapy, University Hospital of Frankfurt, 60528 Frankfurt, Germany
| | - Anja Urbach
- Department of Neurology, Jena University Hospital, Am Klinikum 1, 07747 Jena, Germany; Jena Center for Healthy Aging, Jena University Hospital, Am Klinikum 1, 07747 Jena, Germany; Leibniz Institute on Aging, Aging Research Center Jena, Beutenbergstr. 11, 07745 Jena, Germany
| | - Michael Bauer
- Center for Sepsis Control and Care, Jena University Hospital, Am Klinikum 1, 07747 Jena, Germany; Department of Anesthesiology and Intensive Care, Jena University Hospital, Am Klinikum 1, 07747 Jena, Germany
| | - Klaus V Toyka
- Department of Neurology, University of Würzburg, 97080 Würzburg, Germany
| | - Markus Blaess
- Center for Sepsis Control and Care, Jena University Hospital, Am Klinikum 1, 07747 Jena, Germany; Institute of Precision Medicine, Medical and Life Sciences Faculty, Furtwangen University, 78054 Villingen-Schwenningen, Germany
| | - Ralf A Claus
- Center for Sepsis Control and Care, Jena University Hospital, Am Klinikum 1, 07747 Jena, Germany; Department of Anesthesiology and Intensive Care, Jena University Hospital, Am Klinikum 1, 07747 Jena, Germany
| | - Rainer König
- Center for Sepsis Control and Care, Jena University Hospital, Am Klinikum 1, 07747 Jena, Germany; Department of Anesthesiology and Intensive Care, Jena University Hospital, Am Klinikum 1, 07747 Jena, Germany
| | - Christian Geis
- Center for Sepsis Control and Care, Jena University Hospital, Am Klinikum 1, 07747 Jena, Germany; Section Translational Neuroimmunology, Department of Neurology, Jena University Hospital, Am Klinikum 1, 07747 Jena, Germany; German Center for Mental Health (DZP), Center for Intervention and Research on Adaptive and Maladaptive Brain Circuits Underlying Mental Health (C-I-R-C), Jena-Magdeburg-Halle, Jena, Germany.
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Hunter D, Petit-Pedrol M, Fernandes D, Bénac N, Rodrigues C, Kreye J, Ceanga M, Prüss H, Geis C, Groc L. Converging synaptic and network dysfunctions in distinct autoimmune encephalitis. EMBO Rep 2024; 25:1623-1649. [PMID: 38253690 PMCID: PMC10933378 DOI: 10.1038/s44319-024-00056-2] [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: 08/29/2023] [Revised: 12/18/2023] [Accepted: 01/02/2024] [Indexed: 01/24/2024] Open
Abstract
Psychiatric and neurological symptoms, as well as cognitive deficits, represent a prominent phenotype associated with variable forms of autoimmune encephalitis, regardless of the neurotransmitter receptor targeted by autoantibodies. The mechanistic underpinnings of these shared major neuropsychiatric symptoms remain however unclear. Here, we investigate the impacts of patient-derived monoclonal autoantibodies against the glutamatergic NMDAR (NMDAR mAb) and inhibitory GABAaR (GABAaR mAb) signalling in the hippocampal network. Unexpectedly, both excitatory and inhibitory synaptic receptor membrane dynamics, content and transmissions are altered by NMDAR or GABAaR mAb, irrespective of the affinity or antagonistic effect of the autoantibodies. The effect of NMDAR mAb on inhibitory synapses and GABAaR mAb on excitatory synapses requires neuronal activity and involves protein kinase signalling. At the cell level, both autoantibodies increase the excitation/inhibition balance of principal cell inputs. Furthermore, NMDAR or GABAaR mAb leads to hyperactivation of hippocampal networks through distinct alterations of principal cell and interneuron properties. Thus, autoantibodies targeting excitatory NMDAR or inhibitory GABAaR trigger convergent network dysfunctions through a combination of shared and distinct mechanisms.
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Affiliation(s)
- Daniel Hunter
- University of Bordeaux, CNRS, Interdisciplinary Institute for Neuroscience, IINS, UMR 5297, F-33000, Bordeaux, France
| | - Mar Petit-Pedrol
- University of Bordeaux, CNRS, Interdisciplinary Institute for Neuroscience, IINS, UMR 5297, F-33000, Bordeaux, France
| | - Dominique Fernandes
- University of Bordeaux, CNRS, Interdisciplinary Institute for Neuroscience, IINS, UMR 5297, F-33000, Bordeaux, France
| | - Nathan Bénac
- University of Bordeaux, CNRS, Interdisciplinary Institute for Neuroscience, IINS, UMR 5297, F-33000, Bordeaux, France
| | - Catarina Rodrigues
- University of Bordeaux, CNRS, Interdisciplinary Institute for Neuroscience, IINS, UMR 5297, F-33000, Bordeaux, France
| | - Jakob Kreye
- German Center for Neurodegenerative Diseases (DZNE) Berlin, 10117, Berlin, Germany
- Department of Neurology and Experimental Neurology, Charité-Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität Berlin, 10117, Berlin, Germany
| | - Mihai Ceanga
- Hans-Berger Department of Neurology, Jena University Hospital, Jena, Germany
| | - Harald Prüss
- German Center for Neurodegenerative Diseases (DZNE) Berlin, 10117, Berlin, Germany
- Department of Neurology and Experimental Neurology, Charité-Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität Berlin, 10117, Berlin, Germany
| | - Christian Geis
- Hans-Berger Department of Neurology, Jena University Hospital, Jena, Germany
| | - Laurent Groc
- University of Bordeaux, CNRS, Interdisciplinary Institute for Neuroscience, IINS, UMR 5297, F-33000, Bordeaux, France.
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