Project description:We profiled the zebrafish thymus by single-cell RNA sequencing to investigate the heterogeneity of zebrafish thymic epithelial cells and determine whether similar mimetic cell populations to those found in mice and humans might also exist in the zebrafish.
Project description:The zinc-finger transcription factor Ikaros (Ikzf1) modulates key gene expression programs important for hematopoietic development, and coding mutations in IKZF1 are found in patients with immunodeficiency, leukemia, and autoimmunity. While Ikaros has a well-established function in hematopoiesis, its role in other cell types is less well defined. Here, we uncover new functions for Ikaros in thymic epithelial lineage development and show that Ikzf1 expression in medullary thymic epithelial cells (mTECs) is required for both Autoimmune Regulator positive (Aire+) mTEC development and tissue-specific antigen (TSA) gene expression. Accordingly, TEC-specific deletion of Ikzf1 in mice results in a profound decrease in Aire+ mTECs, a global loss of TSA gene expression, and the development of autoimmunity. Moreover, Ikaros shapes thymic mimetic cell diversity and its deletion results in a dramatic expansion of thymic tuft cells and muscle-like mTECs and a loss of other Aire-dependent mimetic populations. Single-cell analysis reveals Ikaros modulates core transcriptional programs in TECs that correlate with the observed cellular changes. Our findings highlight a previously undescribed role for Ikaros in regulating epithelial lineage development and function, and suggest that failed thymic central tolerance could contribute to the autoimmunity seen in humans with IKZF1 mutations.
Project description:To examine the transcriptome of various mimetic thymic epithelial cell populations (CilTEC, MyoTEC, Hetero-post TEC, microfold TEC, endocrine TEC and corneoTEC) we sorted these populations from young WT mice and performed bulk RNAseq