Elexacaftor/Tezacaftor/Ivacaftor alters branching morphogenesis of the mouse embryonic lung

IntroductionCFTR modulators triple combo-therapy Elexacaftor/Tezacaftor/Ivacaftor (ETI) has proven to clinically benefit homozygous and heterozygous F508del patients. As a result, an increasing number of pregnancies is expected. Studies of the potential impact of these modulators on the development of the foetus are mandatory. MaterialsWe used the early mouse embryonic lung organ culture model to analyse ex vivo the lung branching process and the relative expression of Fgf10, Fgfr2IIIb, Shh, and Hhip development regulator genes in different conditions: standard culture medium, treatment with ETI or with Forskolin {+/-} Inh172. Development of lung branching and distal bud caliber were evaluated in lung explants from heterozygous F508del Cftrtm1Eur/+ and control Cftrtm1Eur+/+ (WT) mouse embryos at E12.5 during pseudo-glandular stage. ResultsExposure to ETI of the Cftrtm1Eur/+ and WT lung explants induced a significant decrease in lung branching after 48h culture and the percentage of terminal bud dilations was significantly increased. These results were recapitulated by cAMP-dependent CFTR continuous activation by Forskolin and reversed by addition of Inh172. ETI induced a significant decrease in Fgf10, Fgfr2IIIb, Shh and Hhip expression in lung explants of both E12.5 Cftrtm1Eur/+ and WT embryos treated with ETI for 72h. ConclusionOur results provide evidence that the triple association Elexacaftor/Tezacaftor/Ivacaftor alters lung branching morphogenesis of WT and heterozygous F508del mouse embryos during the pseudo-glandular stage. Those results argue for a close monitoring of pregnancies in patients treated with these drugs. Plain LanguageO_ST_ABSIntroductionC_ST_ABSThe triple combo-therapy Elexacaftor/Tezacaftor/Ivacaftor (ETI) improves homozygous and heterozygous F508del patients. As a result, an increasing number of pregnancies is expected. Studies of this treatment on the development of the foetus are lacking. We incubated lungs of murine foetus not carrying CFTR mutation or F508del heterozygous. We show that ETI induces significant defect of lung development and the formation of cysts. These results are at least partly due to CFTR activation. Those results argue for a close monitoring of pregnancies in patients treated with these drugs.