Re-engineering of AAV particle by "peptide insertion" method

2019 Fiscal Year Final Research Report

• Project/Area Number: 18K19298
• Research Category: Grant-in-Aid for Challenging Research (Exploratory)
• Allocation Type: Multi-year Fund
• Review Section: Medium-sized Section 43:Biology at molecular to cellular levels, and related fields
• Research Institution: Osaka University
• Principal Investigator: Takagi Junichi 大阪大学, 蛋白質研究所, 教授 (90212000)
• Project Period (FY): 2018-06-29 – 2020-03-31
• Keywords: アデノ随伴ウイルス / 環状ペプチド / ターゲッティング / 遺伝子治療

Outline of Final Research Achievements

In this study, we aimed at changing the cellular tropism of adeno-associated virus (AAV), one of the most promising vector for gene therapy. Although AAV can infect many cell types, the infection efficiency is not high enough to warrant its broad application in gene therapy. The broad tropism can also be a problem where gene delivery needs to be restricted to a specific organ/tissue. In order to achieve greater control of AAV's cellular infectivity, we chose “peptide grafting” method to grant AAV capsid to bind to a specific receptor and infect limited type of cells for gene delivery. We first sought for loop positions that allow peptide insertion, and identified 2 candidate sites. Then an artificial peptide sequence derived from a macrocyclic peptide known to bind to Plexin B1 was inserted in these positions. We confirmed that the modified virus was able to infect cells expressing Plexin B1 but not the parent cells, indicating the general applicability of this approach.

Free Research Field

構造生物学

Academic Significance and Societal Importance of the Research Achievements

遺伝子治療は、先天性遺伝子疾患をゲノムレベルで「治療」してしまう夢の技術であるが、様々な課題のためにまだ実現に至っていない。アデノ随伴ウイルス（AAV）は遺伝子治療における最も有望なベクターだが、そのトロピズム（細胞指向性）を随意にコントロールすることが出来ていない。本研究によって、AAVのキャプシドに標的結合能をもつヘアピンペプチドを提示させることによって、特定の受容体を発現する細胞だけに感染し遺伝子発現を誘導できることを示した。つまり、筋肉、肝臓、網膜、などの臓器だけに目的の遺伝子を届ける道が開けたと言える。