Characterization of a Conformation-Restricted Amyloid β Peptide and Immunoreactivity of Its Antibody in Human AD brain

• DOI: 10.1021/acschemneuro.1c00416
• Publication Date: 2021-08-31T18:45:34Z
• Authors: Yusuke Kageyama; Yumi Irie; Yuka Matsushima; Tatsuya Segawa; Jean-Pierre Bellier; Kumi Hidaka; Hiroshi Sugiyama; Daita Kaneda; Yoshio Hashizume; Hiroyasu Akatsu; Kunio Miki; Akiko Kita; Douglas G. Walker; Kazuhiro Irie; Ikuo Tooyama
• Keywords: Immunogen; Thioflavin; Colocalization; Amyloid (mycology)

Characterization of amyloid β (Aβ) oligomers, the transition species present prior to formation Aβ fibrils and that have cytotoxicity, has become one major topics in investigations Alzheimer's disease (AD) pathogenesis. However, studying pathophysiological properties oligomers is challenging due instability these protein complexes vitro. Here, we report conformation-restricted Aβ42 with an intramolecular disulfide bond at positions 17 28 (SS-Aβ42) formed stable Thioflavin T binding assays, nondenaturing gel electrophoresis, morphological analyses revealed SS-Aβ42 maintained oligomeric structure, whereas wild-type highly aggregative mutant E22P substitution (E22P-Aβ42) fibrils. In agreement observations, was more cytotoxic compared E22P-Aβ42 cell cultures. Furthermore, developed a monoclonal antibody, designated TxCo-1, using toxic conformation as immunogen. X-ray crystallography TxCo-1/SS-Aβ42 complex, enzyme immunoassay, immunohistochemical studies confirmed recognition site specificity TxCo-1 SS-Aβ42. Immunohistochemistry antibody identified structures resembling senile plaques vascular brain samples AD subjects. immunoreactivity did not colocalize extensively conventional antibodies. Together, findings indicate turn 22 23, which prone form could show strong cytotoxicity accumulated brains The should facilitate understanding pathological role AD.