AUTHOR=Speck-Hernandez Cesar A. , Assis Amanda F. , Felicio Rafaela F. , Cotrim-Sousa Larissa , Pezzi Nicole , Lopes Gabriel S. , Bombonato-Prado Karina F. , Giuliatti Silvana , Passos Geraldo A. 

TITLE=Aire Disruption Influences the Medullary Thymic Epithelial Cell Transcriptome and Interaction With Thymocytes

JOURNAL=Frontiers in Immunology

VOLUME=9

YEAR=2018

URL=https://www.frontiersin.org/journals/immunology/articles/10.3389/fimmu.2018.00964

DOI=10.3389/fimmu.2018.00964

ISSN=1664-3224

ABSTRACT=<p>The function of medullary thymic epithelial cells (mTECs) is associated with thymocyte adhesion, which is crucial for the negative selection of autoreactive thymocytes in the thymus. This process represents the root of central tolerance of self-components and prevents the onset of autoimmune diseases. Since thymic epithelia correspond to an important target of donor T cells during the onset of chronic graft-vs-host-disease, mTEC-thymocyte adhesion may have implications for alloimmunity. The <italic>Aire</italic> and <italic>Fezf2</italic> genes function as transcriptome controllers in mTECs. The central question of this study is whether there is a mutual relationship between mTEC-thymocyte adhesion and the control of the mTEC transcriptome and whether Aire is involved in this process. Here, we show that <italic>in vitro</italic> mTEC-thymocyte adhesion causes transcriptome changes in mTECs and upregulates the transcriptional expression of <italic>Aire</italic> and <italic>Fezf2</italic>, as well as cell adhesion-related genes such as <italic>Cd80</italic> or <italic>Tcf7</italic>, among others. Crispr-Cas9-mediated <italic>Aire</italic> gene disruption demonstrated that this gene plays a role in the process of mTEC-thymocyte adhesion. Consistent with the nuclear localization signal (NLS) encoded by <italic>Aire</italic> exon 3, which was targeted, we demonstrate that <italic>Aire</italic> KO<sup>−/−</sup> mTECs impair AIRE protein localization in the nucleus. Consequently, the loss of function of <italic>Aire</italic> reduced the ability of these cells to adhere to thymocytes. Their transcriptomes differed from their wild-type <italic>Aire</italic><sup>+/+</sup> counterparts, even during thymocyte adhesion. A set of mRNA isoforms that encode proteins involved in cell adhesion were also modulated during this process. This demonstrates that both thymocyte interactions and <italic>Aire</italic> influence transcriptome profiling of mTEC cells.</p>