The binding property of a monoclonal antibody against the extracellular domains of aquaporin-4 directs aquaporin-4 toward endocytosis
| Autor: | Masato Yasui, Hiroko Iwanari, Takao Hamakubo, Jing-Yan Han, Osamu Kusano-Arai, Julia Ramadhanti, Toshiko Sakihama, Kazuo Fujihara, Ping Huang, Masashi Aoki, Takayuki Miyauchi, Yoichiro Abe, Yoshiki Takai |
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| Rok vydání: | 2016 |
| Předmět: |
Monoclonal antibody
0301 basic medicine medicine.drug_class Biophysics Endocytosis Biochemistry 03 medical and health sciences 0302 clinical medicine Autoimmune disease Extracellular medicine biology Autoantibody Neuromyelitis optica Molecular biology Blot 030104 developmental biology medicine.anatomical_structure Aquaporin 4 biology.protein sense organs Antibody Astrocyte Aquaporin-4 030217 neurology & neurosurgery Research Article |
| Zdroj: | Biochemistry and Biophysics Reports |
| ISSN: | 2405-5808 |
| DOI: | 10.1016/j.bbrep.2016.05.017 |
| Popis: | Neuromyelitis optica (NMO), an autoimmune disease of the central nervous system, is characterized by an autoantibody called NMO-IgG that recognizes the extracellular domains (ECDs) of aquaporin-4 (AQP4). In this study, monoclonal antibodies (mAbs) against the ECDs of mouse AQP4 were established by a baculovirus display method. Two types of mAb were obtained: one (E5415A) recognized both M1 and M23 isoforms, and the other (E5415B) almost exclusively recognized the square-array-formable M23 isoform. While E5415A enhanced endocytosis of both M1 and M23, followed by degradation in cells expressing AQP4, including astrocytes, E5415B did so to a much lesser degree, as determined by live imaging using fluorescence-labeled antibodies and by Western blotting of lysate of cells treated with these mAbs. E5415A promoted cluster formation of AQP4 on the cell surface prior to endocytosis as determined by immunofluorescent microscopic observation of bound mAbs to astrocytes as well as by Blue native PAGE analysis of AQP4 in the cells treated with the mAbs. These observations clearly indicate that an anti-AQP4-ECDs antibody possessing an ability to form a large cluster of AQP4 by cross-linking two or more tetramers outside the AQP4 arrays enhances endocytosis and the subsequent lysosomal degradation of AQP4. Graphical abstract Highlights • Two mAbs against the ECD of mAQP4 with different binding properties was established. • One of them, E5415A, bound to mAQP4 independent of OAP-formation of AQP4. • E5415A but not E5415B strongly enhanced endocytosis of endogenous AQP4 in astrocytes. • E5415A formed large clusters of AQP4 cross-linking multiple AQP4 functional units. • It is the cluster formation of AQP4 that triggers AQP4 endocytosis. |
| Databáze: | OpenAIRE |
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