We’re nearly ready to use CRISPR to target far more diseases

The race is on to edit the DNA in our body to fight or prevent disease. Promising results from animal studies targeting the liver, muscles and the brain suggest that the CRISPR genome-editing method could revolutionise medicine, allowing us to treat or even cure a huge range of disorders. 

The CRISPR genome-editing method was only developed in 2012, but it is proving so powerful and effective that around 20 trials in humans have already begun or will soon. Almost all of these involve removing cells from an individual’s body, editing their DNA and then putting them back into the body.

This approach has immense promise, for instance, it is being used to alter immune cells to make them better at killing cancers. It’s relatively easy to remove immune cells or blood stem cells, edit them, and then return them to the body, but this isn’t possible with most bodily tissues.

So editing cells inside the body would allow us to treat far more conditions – from genetic disorders to high cholesterol – and would also be cheaper than growing and editing cells outside the body. What diseases could be treated this way? “Absolutely everything,” says Irina Conboy of the University of California, Berkeley.

The big challenge is delivering the CRISPR machinery to tissues inside the body. Editing genes with CRISPR requires at least two components: a protein that cuts DNA and a piece of RNA that guides it to the precise DNA site to make the cut. Proteins and RNAs are enormous molecules compared with conventional drugs. It’s hard to get them inside cells, and they don’t usually survive in the bloodstream, either.

But biologists have been working on delivering big molecules to cells for decades and are now adapting various methods for genome editing. Intellia Therapeutics of Cambridge, Massachusetts, for instance, is using fatty particles to deliver the CRISPR components to livers.