A Landscape of CRISPR/Cas Technique for Emerging Viral Disease Diagnostics and Therapeutics: Progress and Prospects

Abstract

Viral diseases have emerged as a serious threat to humanity and as a leading cause of morbidity worldwide. Many viral diagnostic methods and antiviral therapies have been developed over time, but we are still a long way from treating certain infections caused by viruses. Acquired immunodeficiency syndrome (AIDS) is one of the challenges where current medical science advancements fall short. As a result, new diagnostic and treatment options are desperately needed. The CRISPR/Cas9 system has recently been proposed as a potential therapeutic approach for viral disease treatment. CRISPR/Cas9 is a specialised, effective, and adaptive gene-editing technique that can be used to modify, delete, or correct specific DNA sequences. It has evolved into an advanced, configurable nuclease-based single or multiple gene-editing tool with a wide range of applications. It is widely preferred simply because its operational procedures are simple, inexpensive, and extremely efficient. Exploration of infectious virus genomes is required for a comprehensive study of infectious viruses. Herein, we have discussed the historical timeline-based advancement of CRISPR, CRISPR/Cas9 as a gene-editing technology, the structure of CRISPR, and CRISPR as a diagnostic tool for studying emerging viral infections. Additionally, utilizing CRISPR/Cas9 technology to fight viral infections in plants, CRISPR-based diagnostics of viruses, pros, and cons, and bioethical issues of CRISPR/Cas9-based genomic modification are discussed.

Keywords: CRISPR Cas9/based diagnosis; disease treatment; emerging infectious viruses; gene-editing.

Figure 1

Working principle of CRISPR/Cas9 genome editing technology.

Figure 2

Overview of CRISPR activation (CRISPRa) and CRISPR interference (CRISPRi).

Figure 3

Trans-cleavage activity is used by two exemplary CRISPR-based diagnostic techniques, DETECTR and SHERLOCK. (A) Design for DETECTR. The recombinase, single-stranded DNA-binding protein, and strand-displacing polymerase used in RPA, an isothermal alternative to PCR, recognize the target DNA that is amplified by the Cas12a-gRNA complex. When the target is recognized, it breaks apart the nearby ssDNA reporters that are FQ-labelled, restoring the fluorescence. (B) SHERLOCK’s design. The target RNA is in vitro transcribed from the amplified DNA by RPA or RT-RPA, and the Cas13a-gRNA complex attaches to it. This initiates the trans-cleavage of the Cas13a-gRNA complex, which cleaves the surrounding FQ-labelled ssRNA reporters.