AUTHOR=Yull Sarah , Shafiei Shiva , Park Craig B. , Kazemi Parinaz , Tiemann Emily B. , Pagé Marie-Hélène Godin , Dufort Daniel TITLE=Uterine Nodal expression supports maternal immunotolerance and establishment of the FOXP3+ regulatory T cell population during the preimplantation period JOURNAL=Frontiers in Immunology VOLUME=Volume 14 - 2023 YEAR=2023 URL=https://www.frontiersin.org/journals/immunology/articles/10.3389/fimmu.2023.1276979 DOI=10.3389/fimmu.2023.1276979 ISSN=1664-3224 ABSTRACT=

Pregnancy success is dependent on the establishment of maternal tolerance during the preimplantation period. The immunosuppressive function of regulatory T cells is critical to limit inflammation arising from implantation of the semi-allogeneic blastocyst. Insufficient maternal immune adaptations to pregnancy have been frequently associated with cases of female infertility and recurrent implantation failure. The role of Nodal, a secreted morphogen of the TGFβ superfamily, was recently implicated during murine pregnancy as its conditional deletion (NodalΔ/Δ) in the female reproductive tract resulted in severe subfertility. Here, it was determined that despite normal preimplantation processes and healthy, viable embryos, NodalΔ/Δ females had a 50% implantation failure rate compared to NodalloxP/loxP controls. Prior to implantation, the expression of inflammatory cytokines MCP-1, G-CSF, IFN-γ and IL-10 was dysregulated in the NodalΔ/Δ uterus. Further analysis of the preimplantation leukocyte populations in NodalΔ/Δ uteri showed an overabundance of infiltrating, pro-inflammatory CD11bhigh Ly6C+ macrophages coupled with the absence of CD4+ FOXP3+ regulatory T cells. Therefore, it is proposed that uterine Nodal expression during the preimplantation period has a novel role in the establishment of maternal immunotolerance, and its dysregulation should be considered as a potential contributor to cases of female infertility and recurrent implantation failure.