Brain blood vessel autoantibodies in patients with NMDA and GABAA receptor encephalitis: identification of unconventional Myosin-X as target antigen

Lucie Y Li; Jakob Kreye; Malgorzata Burek; César Cordero-Gomez; Paula C Barthel; Elisa Sánchez-Sendín; Hans-Christian Kornau; Dietmar Schmitz; Madeleine Scharf; Patrick Meybohm; S Momsen Reincke; Harald Prüss; Markus Höltje

doi:10.3389/fncel.2023.1077204

Brain blood vessel autoantibodies in patients with NMDA and GABA_A receptor encephalitis: identification of unconventional Myosin-X as target antigen

Front Cell Neurosci. 2023 Jan 30:17:1077204. doi: 10.3389/fncel.2023.1077204. eCollection 2023.

Authors

Lucie Y Li¹, Jakob Kreye^{2

3

4}, Malgorzata Burek⁵, César Cordero-Gomez^{2

3}, Paula C Barthel¹, Elisa Sánchez-Sendín^{2

3}, Hans-Christian Kornau^{2

6}, Dietmar Schmitz^{2

6

7

8

9}, Madeleine Scharf¹⁰, Patrick Meybohm⁵, S Momsen Reincke^{2

3}, Harald Prüss^{2

3}, Markus Höltje¹

Affiliations

¹ Institute of Integrative Neuroanatomy Berlin, Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin and Berlin Institute of Health, Berlin, Germany.
² German Center for Neurodegenerative Diseases (DZNE) Berlin, Berlin, Germany.
³ Department of Neurology and Experimental Neurology, Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität Berlin and Berlin Institute of Health, Berlin, Germany.
⁴ Department of Pediatric Neurology, Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin and Berlin Institute of Health, Berlin, Germany.
⁵ Department of Anaesthesiology, Intensive Care, Emergency and Pain Medicine, University Hospital Würzburg, Würzburg, Germany.
⁶ Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt- Universität zu Berlin and Berlin Institute of Health, Neuroscience Research Center, Berlin, Germany.
⁷ Max Delbrück Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany.
⁸ Einstein Center for Neurosciences Berlin, Berlin, Germany.
⁹ Bernstein Center for Computational Neuroscience Berlin, Berlin, Germany.
¹⁰ Institute of Experimental Immunology, EUROIMMUN AG, Lübeck, Germany.

Abstract

Introduction: The antibody repertoire from CSF-derived antibody-secreting cells and memory B-cells in patients with encephalitis contains a considerable number of antibodies that do not target the disease-defining autoantigen such as the GABA or NMDA receptors. This study focuses on the functional relevance of autoantibodies to brain blood vessels in patients with GABA_A and NMDA receptor encephalitis. Methods: We tested 149 human monoclonal IgG antibodies from the cerebrospinal fluid of six patients with different forms of autoimmune encephalitis on murine brain sections for reactivity to blood vessels using immunohistochemistry. Positive candidates were tested for reactivity with purified brain blood vessels, effects on transendothelial electrical resistance (TEER), and expression of tight junction proteins as well as gene regulation using human brain microvascular endothelial hCMEC/D3 cells as in vitro blood-brain barrier model. One blood-vessel reactive antibody was infused intrathecally by pump injection in mice to study in vivo binding and effects on tight junction proteins such as Occludin. Target protein identification was addressed using transfected HEK293 cells. Results: Six antibodies reacted with brain blood vessels, three were from the same patient with GABA_AR encephalitis, and the other three were from different patients with NMDAR encephalitis. One antibody from an NMDAR encephalitis patient, mAb 011-138, also reacted with cerebellar Purkinje cells. In this case, treatment of hCMEC/D3 cells resulted in decreased TEER, reduced Occludin expression, and mRNA levels. Functional relevance in vivo was confirmed as Occludin downregulation was observed in mAb 011-138-infused animals. Unconventional Myosin-X was identified as a novel autoimmune target for this antibody. Discussion: We conclude that autoantibodies to blood vessels occur in autoimmune encephalitis patients and might contribute to a disruption of the blood-brain barrier thereby suggesting a potential pathophysiological relevance of these antibodies.

Keywords: Myosin-X; autoimmunity; blood-brain barrier; encephalitis; occludin.

Grants and funding

This work was supported by grants from the German Research Foundation (DFG; grants FOR3004, PR1274/3-1, PR1274/5-1, and PR1274/9-1), by the Helmholtz Association (HIL-A03 BaoBab), and by the German Federal Ministry of Education and Research (Connect-Generate 01GM1908D) to HP. We acknowledge financial support from the Open Access Publication Fund of Charitè—Universitätsmedizin Berlin and the German Research Foundation (DFG).