CRISPR - The Next Revolution in Genetic Engineering
Over the last couple of decades, biologists have honed their tools for deleting, replacing or otherwise editing DNA. Now, a strategy called CRISPR (short for clustered regularly interspaced short palindromic repeats) has quickly become one of the most popular ways to do genome engineering. Utilizing a modified bacterial protein and RNA that guides it to a specific DNA location, the CRISPR system provides unprecedented control over genes in many species, including humans.
Genome Editing with CRISPR-Cas9
How CRISPR Works
Biologists have long been able to edit genomes with molecular tools. About ten years ago, they became excited by enzymes called zinc finger nucleases that promised to do this accurately and efficiently. But zinc fingers, which cost $5,000 or more to order, were not widely adopted because they are difficult to engineer and expensive. CRISPR works differently: it relies on an enzyme called Cas9 that uses a guide RNA molecule to home in on its target DNA, then edits the DNA to disrupt genes or insert desired sequences. The total cost using this approach is as little as $30. That has effectively “democratized” the technology so that researchers everywhere can use it.
One of the advantages of CRISPR is that it can be easily be used to edit the genomes of many organisms. Researchers have traditionally relied heavily on model organisms such as mice and fruit flies, partly because they were the only species that came with a good tool kit for genetic manipulation.
What CRISPR Means for Medicine
Researchers see many promising uses for the CRISPR technology - in diagnostics, therapeutics, genetic research for single and multi-gene diseases, and drug development.
One of the first medical applications of CRISPR might be in diagnostics. Jennifer Doudna, a scientist at the University of California, Berkeley and an early pioneer in the use of the technolgy, is studying CRISPR as a diagnostic tool, searching cells for cancerous mutations, for example. “It’s seek and detect, not seek and destroy,” she said.
Companies are already scrambling to use this new technology in medical applications. For example, Editas Medicine was founded in 2013 with $43 million in venture capital financing, with the goal of developing treatments that employ CRISPR to make edits to single base pairs and larger stretches of DNA. The company plans to use CRISPR by harvesting stem cells from a patient’s bone marrow, correcting one or more defective genes with CRISPR, and then returning the cells to the patient’s marrow, which would then produce healthy red blood cells. It aims to treat cystic fibrosis and sickle-cell anemia, each of which are caused by single base pair mutations.
More applications for the gene editing technology are in the works. Other companies entering this field include: Caribou Biosciences, Editas Medicine, CRISPR Therapeutics, and Intellia Therapeutics.
Commercialization of CRISPR
There are a number of strategies that new venture funded start-ups are using to exploit the CRISPR technology, including:
- Building a research platform for researchers – Build a product/service that reduces researcher pain points. Cost may be difficult to reduce, but time to run experiments, control of inputs, and standardized reproducibility could all be improved.
- Building a delivery system – Until now, gene therapy has been limited by our ability to deliver healthy genes to where they are needed in the body. CRISPR offers a mechanism for editing genes in situ, but some sort of delivery system is still necessary to get the desired CRISPR system in the right cell at the right location.
- Building a killer app – Develop a targeted gene therapy that was previously unachievable. This path was possible prior to the development of CRISPR, but CRISPR has dramatically reduced the difficulty of doing so. Large inherited genetic disorder markets such as hemophilia or cystic fibrosis could be targeted.
The combination of our rapidly expanding knowledge of the genome and the cost-effective, efficient method to splice genes offered by CRISPR, finally opens the door to the promise of gene therapy to cure and prevent many diseases. Despite the tremendous potential for CRISPR applications outside of research, scientists have cautioned that there is a need for rules and protocols that protect against the rash use of CRISPR that could irreversibly alter ecosystems. Nonetheless, the discovery of CRISPR is an immediate step change improvement for researchers, with long-term implications that are very promising, but potentially risky.