The gene-editing technique employs prime editors along with advanced enzymes known as recombinases. This method has the potential to lead to universal gene therapies that are effective for conditions like cystic fibrosis.
Researchers at the Broad Institute of MIT and Harvard have enhanced a gene-editing technology that can now efficiently insert or replace entire genes in human cell genomes, potentially making it suitable for therapeutic uses.
The advance, from the lab of Broad core institute member David Liu, could one day help researchers develop a single gene therapy for diseases such as cystic fibrosis that are caused by one of hundreds or thousands of different mutations in a gene. Using this new approach, they would insert a healthy copy of the gene at its native location in the genome, rather than having to create a different gene therapy to correct each mutation using other gene-editing approaches that make smaller edits.
The new method uses a combination of prime editing, which can directly make a wide range of edits up to about 100 or 200 base pairs, and newly developed recombinase enzymes that efficiently insert large pieces of PACE (phage-assisted continuous evolution) to rapidly evolve more efficient versions of Bxb1 in the lab.
The resulting newly evolved and engineered Bxb1 variant (eeBxb1) improved the eePASSIGE method to integrate an average of 30 percent of gene-sized cargo in mouse and human cells, four times more than the original technique and about 16 times more than another recently published method called PASTE.
“The eePASSIGE system provides a promising foundation for studies integrating healthy gene copies at sites of our choosing in cell and animal models of genetic diseases to treat loss-of-function disorders,” Liu said. “We hope this system will prove to be an important step towards realizing the benefits of targeted gene integration for patients.”
With this goal in mind, Liu’s team is now working on combining eePASSIGE with delivery systems such as engineered virus-like particles (eVLPs) that may overcome hurdles that have traditionally limited the therapeutic delivery of gene editors in the body.
Reference: “Efficient site-specific integration of large genes in mammalian cells via continuously evolved recombinases and prime editing” by Smriti Pandey, Xin D. Gao, Nicholas A. Krasnow, Amber McElroy, Y. Allen Tao, Jordyn E. Duby, Benjamin J. Steinbeck, Julia McCreary, Sarah E. Pierce, Jakub Tolar, Torsten B. Meissner, Elliot L. Chaikof, Mark J. Osborn and David R. Liu, 10 June 2024, Nature Biomedical Engineering.
DOI: 10.1038/s41551-024-01227-1
This work was supported in part by the