Spanish researchers have proposed a new CrispR-Cas9 delivery mechanism that can be used to introduce the gene editing tool into cells via the endocytic pathway using a peptide vehicle. The researchers claim this is the first non-covalent strategy for introducing CrispR-Cas9 into cells, and that this strategy performs better than one of the best delivery methods currently being used.
CrispR-Cas9 is a DNS editing tool that allows precise DNA edits to be made, snipping out defective genes and adding new functional genes into the DNA. While the gene editing tool has only been used in a very limited human trial, research in the lab on animal models has shown the gene editing tool to be highly accurate with minimal off-target effects.
However, one problem with CrispR-Cas9 is how to introduce the large Cas9 DNA endonuclease enzyme – which performs the gene cuts – into cells. The currently used method of introduction involves the use of plasmids, which instruct the cell to make Cas9. The problem is that this method could potentially result in “undesired permanent recombination and immunogenic responses,” according to the researchers at the University of Santiago de Compostela in Spain.
The new method, proposed by researchers, uses a penetrating peptide vehicle to deliver Cas9. Cas9 forms a complex with the positive sides of the amphiphilic penetrating peptide to form nanoparticles that can be introduced into cells.
The researchers report that they have used the new CrispR-Cas9 delivery mechanism to introduce Cas9 into cells and perform edits to HeLa cell genomes. They claim that their new delivery mechanism has a similar level of efficiency to the plasmid method, that the peptide amphiphilic vectors can deliver Cas9 in a single incubation step, and that there is less toxicity than one of the best delivery mechanisms currently being trialed.
The paper – Peptide/Cas9 nanostructures for ribonucleoprotein cell membrane transport and gene edition – has recently been published in the journal Chemical Science.