Cytochrome P450 26A1 modulates uterine dendritic cells in mice early pregnancy

Cytochrome P450 26A1 (CYP26A1) plays important roles in the mice peri-implantation period. Inhibiting its expression or function leads to pregnancy failure. However, little is known about the underlying mechanisms involved, especially the relationship between CYP26A1 and immune cells. In this study, using Cyp26a1-specific antisense morpholigos (Cyp26a1-MO) knockdown mice model and pCR3.1-Cyp26a1 vaccine mice model, we found that the number of uterine CD45⁺ CD11c⁺ MHCII^lo-hi F4/80^- dendritic cells (DCs) was significantly decreased in the treated mice. The percentage of mature DCs (CD86^hi ) was obviously lower and the percentage of immature DCs (CD86^lo ) was remarkably higher in uterine DCs in the treatment group than that of the control group. Further experiments found that ID2, a transcription factor associated with DCs development, and CD86, a DC mature marker molecule, were both significantly reduced in mice uteri in the treated group. In vitro, ID2 and CD86 also decreased in bone marrow-derived DCs under Cyp26a1-MO treatment. These findings provide novel information that CYP26A1 might affect the embryo implantation via modulating the differentiation and maturation of uterine DCs.