Innovative Technique Allows for Genetic Alteration of Individual Cells in Adult Animals

A team of scientists has pioneered a method utilizing CRISPR-Cas technology to concurrently alter multiple genes within cellular structures in mature animals. This leads to a mosaic arrangement of changes, streamlining the investigation into genetic maladies. Specifically, this new technique has provided fresh perspectives into the rare genetic condition known as 22q11.2 deletion syndrome and could potentially reduce the necessity for animal testing in future research. Acknowledgement: ETH Zurich

Traditional techniques for discovering the genetic underpinnings of diseases have relied on disabling a single gene in animals to study its physiological impact. However, many disorders are influenced by multiple genes, making the identification of the role of a single gene in such diseases a daunting task. This generally required a series of individual animal tests for each gene alteration being examined.

Led by Randall Platt, Professor of Biological Engineering at ETH Zurich’s Department of Biosystems Science and Engineering, the scientists have introduced an advanced method that significantly expedites and simplifies research involving laboratory animals. Employing CRISPR-Cas, referred to as “gene scissors,” the researchers can modify several dozen genes in the cells of a single animal, resembling a mosaic arrangement.

In this mosaic configuration, although only one gene is changed in each cell, different cells within the same organ undergo varying modifications. This allows for precise cellular-level analysis, thereby enabling the study of the implications of multiple gene alterations within a single research experiment.

Application in Adult Animal Subjects

For the first time, this method has been successfully implemented in adult mice, as reported in a recent publication in the scientific journal Nature. While similar techniques have been developed for cells in culture or animal embryos, this is a groundbreaking application in fully grown animals.

The scientists employed adeno-associated viruses (AAV) to deliver genetic instructions for the CRISPR-Cas mechanism to specific organs. A concoction of viruses with differing instructions was used, enabling the deactivation of various genes within the cells of a singular organ. The brain was the organ of focus for this particular study.

Uncovering New Genes Linked to Disease

Collaborating with the University of Geneva, the researchers at ETH Zurich garnered new insights into the 22q11.2 deletion syndrome, a genetic condition in humans. The condition is associated with a range of symptoms that are often diagnosed as separate disorders, such as schizophrenia and autism spectrum disorders. The researchers concentrated on 29 specific genes active in the mouse brain that relate to this chromosomal region. Subsequent RNA profiling of these modified cells revealed that three genes were predominantly responsible for cellular dysfunction. Among these, two genes had previously not been a significant focus of research.

António Santinha, a Ph.D. candidate in Platt’s research team and the principal author of the study, stated that understanding which genes are abnormally active in certain diseases could pave the way for drug development aimed at counteracting these abnormalities.

Intellectual Property and Future Applications

ETH Zurich has filed for a patent related to this technology. Plans are underway to incorporate it into a start-up enterprise.

Transforming Genomic Research

The technique is part of a broader array of genetic editing methods designed to modify the cellular genome in a mosaic-like fashion. This CRISPR perturbation approach is revolutionizing life sciences research, offering the potential to hasten progress in fields such as biomedical research into the molecular etiologies of genetically complex disorders.

Recently, another research group from ETH Zurich, in collaboration with a team from Vienna, applied CRISPR perturbation to organoids—miniaturized organs derived from stem cells. Both techniques, whether applied to animals or organoids, hold the promise of furnishing more information through fewer experiments, ultimately minimizing the number of animal tests required.

Reference: “Transcriptional linkage analysis with in vivo AAV-Perturb-seq” by Antonio J. Santinha, Esther Klingler, Maria Kuhn, Rick Farouni, Sandra Lagler, Georgios Kalamakis, Ulrike Lischetti, Denis Jabaudon, and Randall J. Platt, published on September 20, 2023, in Nature.
DOI: 10.1038/s41586-023-06570-y

Frequently Asked Questions (FAQs) about CRISPR-Cas Genetic Modification in Adult Animals

More about CRISPR-Cas Genetic Modification in Adult Animals

• ETH Zurich’s Department of Biosystems Science and Engineering
• Introduction to CRISPR-Cas Technology
• 22q11.2 Deletion Syndrome Information
• Nature Journal
• Adeno-Associated Viruses as Gene Delivery Vectors
• Overview of Genetic Disorders
• In Vivo Genome Editing using CRISPR
• Gene Editing and CRISPR Perturbation
• Animal-Free Research Methods in Genetics