Correlative light and electron microscopy (CLEM) to identify propagating synuclein aggregates in the brain

2022 Fiscal Year Final Research Report

• Project/Area Number: 20K07743
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 51030:Pathophysiologic neuroscience-related
• Research Institution: Juntendo University
• Principal Investigator: Koike Masato 順天堂大学, 大学院医学研究科, 教授 (80347210)
• Co-Investigator(Kenkyū-buntansha): 波田野 琢 順天堂大学, 大学院医学研究科, 准教授 (60338390)
• Project Period (FY): 2020-04-01 – 2023-03-31
• Keywords: パーキンソン病 / α-シヌクレイン / 凝集体 / 伝播モデル / p62

Outline of Final Research Achievements

To investigate the time-course of phosphorylated alpha synuclein localization, wild-type mice were sacrificed at 1, 4, 8, and 16 weeks after injection of mouse alpha-synlcein fibril. Many dotted or fibril phosphorylated alpha synuclein-positive structures were observed in the ipsilateral striatum at 4 weeks after injection. At this stage, round-shaped alpha synuclein-positive aggregates were observed in the cortex and substantia nigra. These round-shaped aggregates were mainly localized in the neuronal perikarya, which was confirmed by pre-embedding immunoelectron microscopy. We also investigated the time-course of phosphorylated alpha synuclein localization in p62-GFP knock-in mice. We confirmed colocalization of GFP signals with phosphorylated alpha synuclein by immunohistochemistry. However, GFP fluorescence were too weak to observe directly under the confocal laser microscope.

Free Research Field

神経解剖学

Academic Significance and Societal Importance of the Research Achievements

α-シヌクレインのオリゴマーを動物脳局所へ注入後、リン酸化α-シヌクレイン陽性の凝集体の陽性領域を経時的に評価するin vivoの伝播モデルは、パーキンソン病における病理学的進展機構を明らかにする上で有用である。本研究課題においては、in vivoの実験系の入口にあたるオリゴマー注入と出口の伝播後の凝集体検出の間を繋ぐ凝集体伝播の途中の過程に関する経時的変化について光学顕微鏡レベルのみならず、電子顕微鏡レベルで詳細に検討を行うことに成功した。以上の成果はパーキンソン病における新たなバイオマーカーを見出すことに繋がる所見である。以上が研究成果の学術的、社会的意義である。