In vivo genome editing in animals using AAV-CRISPR system: applications to translational research of human disease.

Cia-Hin Lau,Yousin Suh

doi:10.12688/f1000research.11243.1

Abstract

Adeno-associated virus (AAV) has shown promising therapeutic efficacy with a good safety profile in a wide range of animal models and human clinical trials. With the advent of clustered regulatory interspaced short palindromic repeat (CRISPR)-based genome-editing technologies, AAV provides one of the most suitable viral vectors to package, deliver, and express CRISPR components for targeted gene editing. Recent discoveries of smaller Cas9 orthologues have enabled the packaging of Cas9 nuclease and its chimeric guide RNA into a single AAV delivery vehicle for robust in vivo genome editing. Here, we discuss how the combined use of small Cas9 orthologues, tissue-specific minimal promoters, AAV serotypes, and different routes of administration has advanced the development of efficient and precise in vivo genome editing and comprehensively review the various AAV-CRISPR systems that have been effectively used in animals. We then discuss the clinical implications and potential strategies to overcome off-target effects, immunogenicity, and toxicity associated with CRISPR components and AAV delivery vehicles. Finally, we discuss ongoing non-viral-based ex vivo gene therapy clinical trials to underscore the current challenges and future prospects of CRISPR/Cas9 delivery for human therapeutics.

Highlights

clustered regulatory interspaced short palindromic repeat (CRISPR)/Cas9-based RNA-guided DNA endonuclease is transforming biomedical science research and has quickly become the preferred genome-editing platform for interrogating endogenous gene function in vivo[1,2]
Here, we provide an overview of the state of the art of various associated virus (AAV)-CRISPR systems as well as their principal vector designs for in vivo genome editing in animals
The ex vivo gene-editing approach is commonly used for the therapeutic treatment of blood disorders, cancers, and immune-related diseases

Summary

Introduction

CRISPR (clustered regulatory interspaced short palindromic repeat)/Cas9-based RNA-guided DNA endonuclease is transforming biomedical science research and has quickly become the preferred genome-editing platform for interrogating endogenous gene function in vivo[1,2]. The commonly used CRISPR system can be implemented in mammalian cells by co-expressing Cas[9] nuclease along with chimeric guide RNA (gRNA), which is derived from a synthetic fusion of the CRISPR RNA array (crRNA) and trans-activating crRNA (tracrRNA)[3]. The background of and the recent developments in the CRISPRbased targeted genome-editing toolboxes have been extensively reviewed recently[1,2,6]. Various applications of CRISPR technologies for genome engineering and medical research have been reviewed recently[2,6,7]

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Conclusion