Loss ofPRICKLE1promotes abnormal endometrial epithelial architecture, reduced fertility, and decreased embryo implantation in mice.
Successful embryo implantation requires coordinated changes in the uterine luminal epithelium, including structural alterations, apical-basal polarity shifts, intrauterine fluid resorption, and cellular communication. These processes, collectively termed plasma membrane transformation (PMT), are crucial but poorly understood, especially regarding their regulation by planar cell polarity (PCP) proteins. PCP proteins, essential for cell organization, are understudied in the context of uterine physiology. Prickle proteins, particularly Prickle1, play critical roles in cellular polarization and tissue morphogenesis. However, their function in the endometrial epithelium during embryo implantation is unknown. To investigate Prickle1's role in uterine physiology, we developed an endometrial epithelial conditional knockout (cKO) of Prickle1 using Lactoferrin-icre. PRICKLE1 ablation in the endometrial epithelium resulted in decreased fertility and embryo implantation by gestational day 4.5. Three-dimensional imaging revealed abnormal luminal folding, impaired luminal closure, and altered glandular structure in mutant uteri. Additionally, we observed decreased aquaporin-2 expression, disrupted cellular architecture, and protein expression and localization in mutant uteri. Evidence of epithelial-to-mesenchymal transition (EMT) was found within luminal epithelial cells, further linking PRICKLE1 loss to uterine pathologies. Furthermore, altered cellular division planes and increased multinucleated cells suggested a connection to EMT. Our findings highlight PRICKLE1's critical role in the PCP pathway within the uterus, revealing its importance in the molecular and cellular responses essential for successful pregnancy establishment. Overall design: Whole uteri of Prickle1f/f Ltf-iCre cKO and control mice aged 6 months were isolated. Control samples (n=3) were pooled and cKO samples (n=3) were pooled.