RESUMEN
Medullary thymic epithelial cell (mTEC)-restricted expression of autoimmune regulator (Aire) is essential for establishment of immune tolerance. Recently, Aire was also shown to be expressed in cells of hematopietic and reproductive lineages. Thus, the generation of Airefl/fl mouse strain enables the investigation of the cell-specific function of Aire.
Asunto(s)
Tolerancia Inmunológica/genética , Poliendocrinopatías Autoinmunes/genética , Poliendocrinopatías Autoinmunes/inmunología , Factores de Transcripción/genética , Factores de Transcripción/inmunología , Animales , Células Presentadoras de Antígenos/patología , Linaje de la Célula/genética , Linaje de la Célula/inmunología , Femenino , Humanos , Masculino , Ratones , Ratones Noqueados , Ratones Transgénicos , Poliendocrinopatías Autoinmunes/patología , Reproducción/genética , Reproducción/inmunología , Proteína AIRERESUMEN
The development of thymic regulatory T cells (Treg) is mediated by Aire-regulated self-antigen presentation on medullary thymic epithelial cells (mTECs) and dendritic cells (DCs), but the cooperation between these cells is still poorly understood. Here we show that signaling through Toll-like receptors (TLR) expressed on mTECs regulates the production of specific chemokines and other genes associated with post-Aire mTEC development. Using single-cell RNA-sequencing, we identify a new thymic CD14+Sirpα+ population of monocyte-derived dendritic cells (CD14+moDC) that are enriched in the thymic medulla and effectively acquire mTEC-derived antigens in response to the above chemokines. Consistently, the cellularity of CD14+moDC is diminished in mice with MyD88-deficient TECs, in which the frequency and functionality of thymic CD25+Foxp3+ Tregs are decreased, leading to aggravated mouse experimental colitis. Thus, our findings describe a TLR-dependent function of mTECs for the recruitment of CD14+moDC, the generation of Tregs, and thereby the establishment of central tolerance.