Advances in genome editing technologies, such as CRISPR-Cas, have made it possible to correct mutations in the CFTR gene, with excellent results in experimental models derived from people with cystic fibrosis (CF). However, the main challenge remains transport to the lungs.

One promising method is the use of engineered vesicles, i.e., small “vessels” that can be directed to specific tissues. This system allows the transported material to act only for a limited time in the cells, correcting the CFTR gene without causing unwanted changes in the DNA.

In this project, special virus-derived nanoparticles called VEsiCas were used to generate new vesicles called GE-vesicles.
The new vesicles were loaded with different CRISPR tools: nucleases, which make targeted cuts in DNA, or base editors, which can modify DNA bases. 
Different compositions of their shell, different sizes, and quantities were also tested; finally, their affinity with lung tissue was evaluated.
Once the GE-vesicles had been optimized, the researchers verified their efficiency on standard epithelial cells used in the laboratory and on human bronchial epithelial cells to correct the R553X (a stop mutation) or 3849+10kbC>T (a splicing mutation) mutations. 
The vesicles were further modified to increase their ability to enter lung cells.
The researchers observed that the transport of genome editing systems via vesicles is very efficient in the cell models used, and that the various CRISPR tools inside them are able to effectively correct mutations such as R553X and 3849+10kbC>T. 
The most effective viral envelope for allowing the vesicles to penetrate human respiratory tract cells was also identified.
The results obtained demonstrate that vesicles are a promising technique for delivering CRISPR to the lungs. 

The researchers will evaluate the efficacy of vesicles in vitro in bronchial epithelial cells derived from people with CF; they will also test the efficacy of GE-vesicles containing different CRISPR tools in a mouse animal model, selecting the most suitable envelope.