Murine uterine decidualization is a novel function of autoimmune regulator-beyond immune tolerance.

PROBLEM: Autoimmune polyendocrinopathy, candidiasis, and ectodermal dystrophy (APECED, APS-1) patients characterized by Aire (autoimmune regulator) mutations and Aire homozygous knockouts (Aire(-/-) ) exhibit infertility. It is not clear as to what contributes to infertility in the above.

METHOD OF STUDY: This study investigates the expression of "AIRE in the uterus" and its contribution to early pregnancy of mice by using quantitative real-time PCR analysis, immunohistochemistry, Western blotting, and in vivo Aire silencing experiments.

RESULTS: Aire (Isoform 1a) is expressed in the uterus during the "window of implantation" and decidualization. In vivo Aire silencing interfered with formation of implantation sites and stromal cell transformation by regulating bone morphogenetic protein-2,4 (Bmp2, Bmp4), homeobox A10 (Hoxa10), and insulin-like growth factor-binding protein 1(Igfbp1) leading to pregnancy failure.

CONCLUSION: Our consolidated results on extrathymic uterine expression of AIRE during early pregnancy and decidualization and impaired fertility on in vivo silencing are suggestive of its importance in pregnancy via a role beyond immune tolerance.