Investigation of strain diversity and cytotoxicity of pathogenic amyloids by using alpha-synuclein as a model

2021 Fiscal Year Final Research Report

• Project/Area Number: 19K22539
• Research Category: Grant-in-Aid for Challenging Research (Exploratory)
• Allocation Type: Multi-year Fund
• Review Section: Medium-sized Section 49:Pathology, infection/immunology, and related fields
• Research Institution: Nagasaki University
• Principal Investigator: Taguchi Yuzuru 長崎大学, 医歯薬学総合研究科(医学系), 客員研究員 (20772552)
• Project Period (FY): 2019-06-28 – 2022-03-31
• Keywords: αシヌクレイン / in-register平行βシート / アミロイド / 分子動力学シミュレーション / 細胞毒性 / プリオン蛋白 / プリオン

Outline of Final Research Achievements

We analyzed influences of various mutations on structures of an in-register parallel β-sheet amyloid of an alpha-synuclein (aSyn) by molecular dynamic (MD) simulation and focused on a substitution mutant at residue 84 to isoleucine, aSyn(G84I). We actually expressed aSyn(G84I) on cultured cells and discovered that the mutant was rather prone to aggregate in the cells. We utilized it to collect clues to the structures of aSyn amyloid in live cells by observing how the aggregation tendency of aSyn(G84I) in the cultured cells are affected by various mutations associated with familial Parkinson diseases. We also attempted to investigate molecular mechanisms of cytotoxicity of aSyn amyloids by analyzing gene-expression profiles of the cells harboring aSyn aggregates, although it was not successful. Finally, exploiting analogy of local amino acid sequences between aSyn and prion protein, we modeled a local structure of an abnormal isoform of prion protein and srudied it with MD simulation.

Free Research Field

分子生物学

Academic Significance and Societal Importance of the Research Achievements

aSyn(G84I)の効率良い凝集能を利用して、細胞内aSynアミロイドの凝集抑制または細胞死抑制効果のある薬剤のスクリーニングに利用できると思われ、現在その系の確立を試みている。今回は細胞死の機序解明には至らなかったが、安定発現株で細胞死がコンスタントに生じる条件を同定できれば、遺伝子発現プロファイルの変化の解析によって、aSynアミロイドによる細胞死の機序の手掛かりとなりうる。
また、in-register平行βシートアミロイドの分子動力学シミュレーションの過程で今回開発した手法や知見は、プリオン蛋白を含む他のアミロイド原性蛋白の研究にも応用可能と思われ、研究の発展への寄与が期待できる。