Harnessing brain cortex-derived molecular data to unravel the mechanism underlying the APOE4-associated development of dementia

• Project/Area Number: 20H03578
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 一般
• Review Section: Basic Section 52010:General internal medicine-related
• Research Institution: Hiroshima University
• Principal Investigator: Yamazaki Yu 広島大学, 医系科学研究科(医), 講師 (70866243)
• Co-Investigator(Kenkyū-buntansha): 高橋 哲也 広島国際大学, 総合リハビリテーション学部, 教授 (00435942)
• Project Period (FY): 2020-04-01 – 2023-03-31
• Project Status: Completed (Fiscal Year 2022)
• Budget Amount: ¥14,170,000 (Direct Cost: ¥10,900,000、Indirect Cost: ¥3,270,000); Fiscal Year 2022: ¥5,200,000 (Direct Cost: ¥4,000,000、Indirect Cost: ¥1,200,000); Fiscal Year 2021: ¥4,420,000 (Direct Cost: ¥3,400,000、Indirect Cost: ¥1,020,000); Fiscal Year 2020: ¥4,550,000 (Direct Cost: ¥3,500,000、Indirect Cost: ¥1,050,000)
• Keywords: アルツハイマー病 / APOE / 認知症 / アミロイドβ

Outline of Research at the Start

アルツハイマー病のリスク遺伝子・アポリポ蛋白E4多型（APOE4）は、脳アミロイドβ (Aβ) の蓄積を促進することで同病の発症に寄与するが、その分子基盤の理解は十分でない。申請者らは脳トランスクリプトーム解析を起点に、APOE4脳特異的に生じる遺伝子（ここでは遺伝子Xと記載）の発現上昇を同定した。本研究では「APOE4は遺伝子X発現を介し脳Aβ蓄積を促進させる」という仮説を、ヒトへの展開性を重視した視点で検証する。具体的には、モデル動物の解析と、世界最大規模のブレインバンクと協力し、多数の剖検脳の生化学的解析により、その仮説検証を行う。

Outline of Final Research Achievements

To elucidate the association between APOE4 and the effector molecule AACT, we successfully achieved the following: 1) construction of a conditional gene knockout system using the Cre-loxp system, 2) creation and characterization of novel humanized APOE mouse models, 3) development of a highly sensitive ELISA for quantification of APOE in human clinical samples, and 4) acquisition of multiple polyclonal antibodies capable of detecting neurodegenerative-related proteins. Although unforeseen events occurred during the course of this research project, they led to the discovery of novel protein X in dissected brains and the creation of the humanized APOE mouse models. By utilizing these tools, we will continue to investigate the molecular pathogenesis of neurological disorders such as Alzheimer's disease.

Academic Significance and Societal Importance of the Research Achievements

アルツハイマー病発症の最も強い遺伝的危険因子はアポリポ蛋白E（APOE）遺伝子であり、APOE4対立遺伝子は劇的に認知症発症リスクを高める一方、APOE2対立遺伝子は保護的に働く。本研究計画により得られた、ヒト化APOEマウスや剖検脳中の新規タンパクXを特異的に認識する抗体は、現在進行中の臨床試験や将来の臨床試験に不可欠な実験病理学的ツールとなり、APOEを標的とする治療法開発に関する新知見を提供する可能性がある。

Research Products

• [Journal Article] Amyloid Beta Is Internalized via Macropinocytosis, an HSPG- and Lipid Raft-Dependent and Rac1-Mediated Process (2022)
  • Author(s): Keyoumu Nazere, Tetsuya Takahashi, Naoyuki Hara, Kazuki Muguruma, Masahiro Nakamori, Yu Yamazaki, Hiroyuki, Morino Hirofumi, Maruyama
  • Journal Title: Frontiers in Molecular Neuroscience Volume: - Pages: 804702-804702
  • DOI: 10.3389/fnmol.2022.804702
  • Peer Reviewed / Open Access
• [Presentation] Association of DNA methylation from the temporal cortex and cerebellum with AD-related neuropathology and biochemistry (2022)
  • Author(s): Stephanie R Oatman, Mariet Allen, Zachary Quicksall, Joseph S Reddy, Minerva M Carrasquillo, Xue Wang, Chia-Chen Liu, Yu Yamazaki, Thuy Nguyen, Michael G Heckman, Yuka A Martens, Na Zhao, Michael DeTure, Melissa E Murray, Takahisa Kanekiyo, Dennis W Dickson, Guojun Bu, Nilufer Ertekin-Taner
  • Organizer: Alzheimer's Association International Conference
  • Int'l Joint Research
• [Presentation] Transcriptome profiling in AD cases to identify distinct associations with AD-related neuropathology and protein levels in the brain (2022)
  • Author(s): Mariet Allen, Zachary Quicksall, Xue Wang, Joseph S Reddy, Jeremiah Bergman, Stephanie R Oatman, Thuy Nguyen, Kimberly G Malphrus, Sarah J Lincoln, Yu Yamazaki, Yuka A Martens, Na Zhao, Michael DeTure, Melissa E Murray, Chia-Chen Liu, Takahisa Kanekiyo, Dennis W Dickson, Guojun Bu, Nilufer Ertekin-Taner
  • Organizer: Alzheimer's Association International Conference
  • Int'l Joint Research