Nanoparticle gene editing restores CFTR function in cystic fibrosis lab model

UCLA researchers have developed a lipid nanoparticle-based gene-editing approach capable of inserting an entire healthy gene into human airway cells, restoring key biological function in a laboratory model of cystic fibrosis and establishing a potential new path toward mutation-agnostic gene therapy for inherited lung diseases. The study in Advanced Functional Materials shows that lipid nanoparticles can be engineered to carry the molecular cargo required for precise insertion of a large full-length gene into the genome without using viral vectors.

Cystic fibrosis is caused by mutations in a single gene, the cystic fibrosis transmembrane conductance regulator, or CFTR, which encodes a channel that helps move chloride and water across the surface of airway cells. Although highly effective drugs known as CFTR modulators have transformed care for many people with cystic fibrosis, about 10% of patients produce little or no CFTR protein at all, leaving nothing for those drugs to act on.

Since there are more than 1,700 different mutations in the CFTR gene that can cause cystic fibrosis, the team looked to develop a universal approach that could correct any of these errors in a single edit rather than individually. In this study, the team used lipid nanoparticles as a non-viral delivery system engineered to transport three gene-editing components simultaneously: CRISPR machinery to cut DNA at a precise location, guide molecules to target the correct genomic site, and a DNA template encoding a full, functional copy of the CFTR gene.

The researchers tested the system in lab-grown human airway cells carrying a severe cystic fibrosis mutation that does not respond to existing drugs. The nanoparticles successfully delivered a healthy CFTR gene into about 3% to 4% of the cells. Despite that relatively small fraction of corrected cells, the treatment restored between 88% and 100% of normal CFTR channel function across the cell population.

The researchers said the strength of that recovery reflects not just where the gene was inserted, but how it was engineered. The replacement CFTR gene was designed to maximize protein production once it entered the cell, enabling even a small number of corrected cells to have an outsized effect. That gene design, known as codon optimization, boosts CFTR protein production without altering the protein itself.

Unlike approaches that deliver messenger RNA, which must be repeatedly re-dosed, the new strategy inserts the corrected gene directly into the genome, potentially allowing cells and their descendants to continue producing functional CFTR over time. For long-term benefit, however, gene editing ultimately needs to reach airway stem cells, which sit deep within the lung's protective lining and regenerate the airway throughout a person's life. Reaching those cells remains one of the biggest challenges ahead because the airway is designed to block foreign particles, and in patients with cystic fibrosis, thick mucus creates an additional barrier.

The researchers described the work as a proof of concept and said future work will need to improve delivery to airway stem cells for a durable, one-time therapy.