Differential features of AIRE-induced and AIRE-independent promiscuous gene expression in thymic epithelial cells

C St-Pierre, A Trofimov, S Brochu… - The Journal of …, 2015 - journals.aai.org
C St-Pierre, A Trofimov, S Brochu, S Lemieux, C Perreault
The Journal of Immunology, 2015journals.aai.org
Establishment of self-tolerance in the thymus depends on promiscuous expression of tissue-
restricted Ags (TRA) by thymic epithelial cells (TEC). This promiscuous gene expression
(pGE) is regulated in part by the autoimmune regulator (AIRE). To evaluate the
commonalities and discrepancies between AIRE-dependent and-independent pGE, we
analyzed the transcriptome of the three main TEC subsets in wild-type and Aire knockout
mice. We found that the impact of AIRE-dependent pGE is not limited to generation of TRA …
Abstract
Establishment of self-tolerance in the thymus depends on promiscuous expression of tissue-restricted Ags (TRA) by thymic epithelial cells (TEC). This promiscuous gene expression (pGE) is regulated in part by the autoimmune regulator (AIRE). To evaluate the commonalities and discrepancies between AIRE-dependent and-independent pGE, we analyzed the transcriptome of the three main TEC subsets in wild-type and Aire knockout mice. We found that the impact of AIRE-dependent pGE is not limited to generation of TRA. AIRE decreases, via non–cell autonomous mechanisms, the expression of genes coding for positive regulators of cell proliferation, and it thereby reduces the number of cortical TEC. In mature medullary TEC, AIRE-driven pGE upregulates non-TRA coding genes that enhance cell–cell interactions (eg, claudins, integrins, and selectins) and are probably of prime relevance to tolerance induction. We also found that AIRE-dependent and-independent TRA present several distinctive features. In particular, relative to AIRE-induced TRA, AIRE-independent TRA are more numerous and show greater splicing complexity. Furthermore, we report that AIRE-dependent versus-independent TRA project nonredundant representations of peripheral tissues in the thymus.
journals.aai.org