Chronic lung infection does not impair lentiviral vector gene transfer in a cystic fibrosis rat model

Genetic therapies offer a promising strategy for treating cystic fibrosis (CF) lung disease, particularly for individuals with modulator-ineligible genotypes. However, clinical translation has been slower than anticipated. While CF gene therapy candidates typically demonstrate high efficacy in preclinical studies, all products trialled to date have failed to progress beyond Phase I/II, raising questions about the predictive capacity of current preclinical models. One contributing factor may be the absence of severe muco-obstructive lung disease in commonly used CF rodent models, highlighting the need to evaluate gene vectors under conditions that more closely recapitulate the CF lung environment. In this study, we evaluated a vesicular stomatitis virus glycoprotein G (VSV-G) pseudotyped lentiviral (LV) vector carrying the luciferase reporter gene under conditions of Pseudomonas aeruginosa lung infection in wild-type and CF rats. Bioluminescence imaging was conducted on days 7 and 14 post-LV vector administration to assess lung transgene expression under infected and non-infected conditions. At day 7, there was no significant difference in bioluminescence between P. aeruginosa -infected and non-infected animals ( p = 0.537). From day 7 to day 14, bioluminescence decreased 136-fold in non-infected animals ( p < 0.0001), compared with a 7-fold decrease in infected animals ( p = 0.043), with a significant infection × time interaction indicating that the magnitude of decline was greater in non-infected controls ( p = 0.024). These findings demonstrate that lung disease state can modulate transgene expression and persistence, highlighting the importance of evaluating gene therapy vectors under conditions that more closely mimic the CF lung environment.