Endometrium-derived organoids from cystic fibrosis patients and mice as new models to study disease-associated endometrial pathobiology.

Cystic fibrosis (CF) is a life-shortening genetic disorder, caused by mutations in the CF transmembrane conductance regulator (CFTR) protein that regulates ion and fluid transport in epithelial tissue. Female CF patients face considerable fertility challenges, with higher prevalence of deficient fertility compared to healthy women. Not much is known about the underlying causes. In particular, the pathobiology of the endometrium, the uterus' inner lining essential for pregnancy and expressing fluctuating CFTR levels during the menstrual cycle, is unexplored in CF. To address this gap, we developed organoid models from CF patient endometrium. The organoids recapitulated CF characteristics and revealed molecular and pathway differences in cycle-recapitulating hormone responses compared to healthy endometrial organoids. Furthermore, specific functional aberrations were restored by CFTR modulator treatment. To further complement human organoid models for unraveling endometrial pathobiology in CF, we also developed organoids from a genetic CF mouse model that were also found to recapitulate CF characteristics. Moreover, single-cell RNA-sequencing analysis of the CF mouse uterus revealed molecular traits in the endometrium similar to the human CF endometrium (as evidenced by its organoid model). Our study provides new endometrium models to advance our understanding of CF-associated endometrial pathobiology, particularly regarding menstrual cycle aberrations that impact fertility. This research is timely since improved CF therapeutics result in increased life expectancy, allowing more CF patients to consider starting a family.