Project description:Eos expression in Treg cells have been documented by several microarrays including ours. We hypothesized that Eos facilitates Foxp3- dependent gene repression in Regulatory T cells. In order to investigate the role of Eos in mediating the Foxp3-dependent gene silencing program, we utilized lentiviral shRNA knockdown of Eos in natural Tregs isolated from the periphery of Balb/C mice. A renilla luciferase (RL) gene specific shRNA lentivirus was used as a control for the transduction of cells. The transcriptional profile of naive T cells, natural Tregs, Eos knockdown Tregs, and control shRNA knockdown Tregs was compared using Agilent 4x 44K whole mouse genome array. The goal of this microarray is to document the global effect of the loss of Eos expression on the transcriptional profile of natrual Treg cells.
Project description:At sites of inflammation, certain Foxp3+ Tregs have the ability to alter their phenotype and become pro-inflammatory helper/effector cells, without losing Foxp3 expression. We show that this functional reprogramming is controlled by the transcription factor Eos (Ikzf4), an obligate co-repressor for Foxp3. The ability to reprogram was restricted to a specific subset of Foxp3+ Tregs, arising as early as the thymus and identifiable by short half-life of Eos at rest, characteristic cell-surface markers (CD38+CD69+CD103NEG) and a distinct pattern of DNA methylation. Mice made selectively deficient in this subset of Eos-labile Tregs became markedly impaired in their ability to cross-present new antigens and prime CD8+ T cells. Downregulation of Eos and consequent Treg reprogramming was prevented by the immunoregulatory enzyme IDO, via activation of the aryl hydrocarbon receptor (AhR). Thus, the Foxp3+ lineage contains a committed subset of Tregs that are constitutively primed for conversion into biologically important helper cells. Cells from thymus or spleen were incubated for 1 hr with cycloheximide (CHX), then CD4+GFP+ Tregs were FACS-sorted into Eos-labile (CD38+CD103NEG) and Eos-stable (CD103+CD38NEG) subsets. Control CD4+GFPNEG (non Treg) cells were sorted from spleen. Genome-wide differential methylation analysis was performed using Reduced Representation Bisulfite Sequencing (RRBS). The genomic DNA from each sample was digested with the methylation-insensitive restriction enzyme MspI (restriction site, CCGG) and ligated to Illumina sequencing adaptors containing methylated cytosine residues. The ligated MspI fragments were size-selected, treated with sodium bisulfite, and amplified by PCR. The PCR products were purified and sequenced using Illumina HiSeq 2000 sequencer with a read length of 100bp.