Cornerstones of CRISPR-Cas in drug discovery and therapy

Abstract

The recent development of CRISPR-Cas systems as easily accessible and programmable tools for genome editing and regulation is spurring a revolution in biology. Paired with the rapid expansion of reference and personalized genomic sequence information, technologies based on CRISPR-Cas are enabling nearly unlimited genetic manipulation, even in previously difficult contexts, including human cells. Although much attention has focused on the potential of CRISPR-Cas to cure Mendelian diseases, the technology also holds promise to transform the development of therapies to treat complex heritable and somatic disorders. In this Review, we discuss how CRISPR-Cas can affect the next generation of drugs by accelerating the identification and validation of high-value targets, uncovering high-confidence biomarkers and developing differentiated breakthrough therapies. We focus on the promises, pitfalls and hurdles of this revolutionary gene-editing technology, discuss key aspects of different CRISPR-Cas screening platforms and offer our perspectives on the best practices in genome engineering.

Figure 1. Pipeline of CRISPR-Cas-assisted drug discovery

Unmet medical needs for numerous diseases and the rapid progress of CRISPR-Cas gene editing can feed into a drug discovery and development pipeline, leading to improved therapies. The CRISPR-Cas system allows for improved target identification and validation, and faster generation of safety models. CRISPR-Cas can also be used to develop cell-based therapies such as CAR T cells for immunotherapy and CCR5 knockout cells for HIV treatment. CRISPR-Cas-assisted drug discovery will yield innovative therapies and treatment paradigms for patients.

Figure 2. CRISPR-Cas in the generation of cellular models and large-scale screens

CRISPR-Cas gene editing can be used to generate isogenic cell lines for drug target validation, mechanistic analysis and patient stratification studies. Isogenic cell lines can also be used to generate organoids, which are particularly useful for modelling differentiation and self-organization processes. Large-scale sgRNA libraries can be used for high-throughput pooled or high-content arrayed screens, either on unmodified or CRISPR-Cas-edited cell lines.

Figure 3. Applications of CRISPR-Cas for in vivo screens and the generation of animal models

a | Ex vivo editing can be used to generate a library of modified cells for transplantation into recipient animals. Alternatively, editing reagents can be delivered to host animal tissues directly for somatic in situ editing. b | CRISPR-Cas has also revolutionized the generation of transgenic animal models through facile editing of ESCs for traditional gene targeting and by enabling direct zygote editing in most species. Zygote editing can be done ex vivo by electroporating or microinjecting zygotes with CRISPR-Cas constructs in the form of plasmids, RNA preparations or RNPs