CRISPR-Cas13 emerges as a game changer in RNA-targeted therapies

In recent years, the scientific community has made significant strides in the field of gene editing, particularly through the development of the CRISPR (Clustered Regularly Interspaced Short Palindromic Repeats) systems. In 2020, the Nobel Prize in Chemistry was awarded to the scientists for the discovery of CRISPR–Cas9 system, a revolutionary genome editing technology that advanced DNA therapeutics. Subsequently, the CRISPR–Cas13 system has emerged as a potential tool to identify and rectify errors in RNA sequences. CRISPR–Cas13 is a novel technology is specifically engineered for virus detection and RNA-targeted therapeutics. The CRISPR RNA (CrRNA) targets specific and non-specific RNA sequences, and Cas13 is an effector protein that undergoes conformational changes and cleaves the target RNA. This RNA-targeting system holds tremendous promise for therapeutics and presents a revolutionary tool in the landscape of molecular biology.

Now, in a recently published BioDesign Research study, a team of researchers led by Professor Yuan Yao from ZJU-Hangzhou Global Scientific and Technological Innovation Center, Zhejiang University, China has elucidated the latest research trends of CRISPR–Cas13 in RNA-targeted therapies. Talking about this paper, which was published online on 6 September 2024, in Volume 6 of the journal, Prof. Yao says, "By focusing on RNA-;the intermediary between DNA and proteins-;CRISPR-Cas13 allows scientists to temporarily manipulate gene expression without inducing permanent changes to the genome. This flexibility makes it a safer option in scenarios where genome stability is critical ."

RNA plays a central role in carrying genetic information from DNA to protein-synthesizing machinery, and also regulates gene expression and participates in numerous cellular processes. Defects in RNA splicing or mutations can lead to a wide variety of diseases, ranging from metabolic disorders to cancer. A point mutation occurs when a single nucleotide is erroneously inserted, deleted, or changed. CRISPR–Cas13 plays a role in identifying and correcting these mutations by employing REPAIR (RNA editing for programmable A-to-I replacement) and RESCUE (RNA editing for specific C-to-U exchange) mechanisms. Explaining the applications of Cas13-based gene editors, Prof. Yao adds, "The mxABE editor, for example, can be used to correct a nonsense mutation linked with Duchenne muscular dystrophy that can be corrected with mxABE. This approach has proved high editing efficiency, restoring dystrophin expression to levels more than 50% of those of the wild type."

CRISPR–Cas13 can rectify unusual splicing events. Demethylase is an enzyme that plays a crucial role in post-transcriptional modification (PTM), a process that occurs after transcription and precedes protein production. Harnessing knowledge about splicing events, and understanding the role of demethylases with the help of CRISPR–Cas13 can help scientists to develop targeted and personalized therapies. Similarly, CRISPR–Cas13 machinery can be applied to alter, upregulate, or downregulate translation. "One of the most significant recent advancements in the CRISPR-Cas13 field is the integration of artificial intelligence (AI) to enhance its precision and efficiency ," says Prof. Yao.

The success of RNA-targeting CRISPR tools depends on multiple factors, including the guide RNA sequence, the accessibility of the target RNA, and the secondary structure of the RNA molecule. The CRISPR–Cas13 system has wide clinical applications, such as diagnostics for RNA viruses, RNA imaging, RNA-base editing, RNA epigenome editing, and therapeutic interventions. Off-target of CRISPR–Cas13 and the large size of the delivery machinery are some of the clinical hurdles slowing down its clinical implementation. But combining molecular techniques with AI can improve efficiency. AI algorithms have the power to predict and optimize CRISPR–Cas13 delivery outcomes.

Going further, CRISPR–Cas13 systems are likely to continue their rapid evolution. As researchers refine the technology, there is potential for its use in an even wider range of therapeutic applications, from antiviral treatments-;such as targeting SARS-CoV-2-;to personalized medicine approaches for genetic diseases.

Finally, the advent of CRISPR–Cas13 has undoubtedly revolutionized RNA editing, offering a powerful tool for addressing some of the most challenging diseases of our time. Hopefully, with the ongoing improvements in specificity, delivery, and AI integration, CRISPR–Cas13 could pave the way for a new era of RNA-targeted therapies.