Project description:Chromatin accessibility of bone marrow conventional T cells, pTregs, tTregs, BMAC-induced Tregs and in vitro-induced Tregs were compared Bone marrow (BM) harbors a large repertoire of regulatory T (Treg) cells, which are essential in hematopoiesis and peripheral tolerance. Treg cell accumulation in BM has been viewed as a consequence of preferential immigration of thymus-derived Treg cells. Here we report a novel subset of antigen presenting cells, which expresses the autoimmune regulator (Aire). These BM Aire-expressing cells resemble a subset of CD138+B220-TACI+Blimp-1+MHC-II+ plasma cells (pc-BMACs) and express a diverse repertoire of tissue-restricted self-antigens. pc-BMACs present self-antigens to na ve CD4+ T cells and can efficiently convert these into functionally competent CD25+Foxp3+ bona fide peripheral Treg cells (pTregs) capable of exerting immune suppression in vitro and in vivo. Aire expression may contribute to the tolerogenic function of pc-BMACs as it regulates the expression of genes involved in pTreg induction and function, including Icosl and retinoic acid synthesis-related genes, Aldh1a2 and Aldh1b1. Our data thus demonstrate an Aire-expressing plasma cell subset in the BM capable to promote peripheral tolerance by ectopically expressing tissue-restricted self-antigens and generating pTregs.
Project description:Chromatin accessibility of bone marrow-resident Aire expressing cells was compared to those of bone marrow plasma cells and B cells via ATAC-seq Bone marrow (BM) harbors a large repertoire of regulatory T (Treg) cells, which are essential in hematopoiesis and peripheral tolerance. Treg cell accumulation in BM has been viewed as a consequence of preferential immigration of thymus-derived Treg cells. Here we report a novel subset of antigen presenting cells, which expresses the autoimmune regulator (Aire). These BM Aire-expressing cells resemble a subset of CD138+B220-TACI+Blimp-1+MHC-II+ plasma cells (pc-BMACs) and express a diverse repertoire of tissue-restricted self-antigens. pc-BMACs present self-antigens to na ve CD4+ T cells and can efficiently convert these into functionally competent CD25+Foxp3+ bona fide peripheral Treg cells (pTregs) capable of exerting immune suppression in vitro and in vivo. Aire expression may contribute to the tolerogenic function of pc-BMACs as it regulates the expression of genes involved in pTreg induction and function, including Icosl and retinoic acid synthesis-related genes, Aldh1a2 and Aldh1b1. Our data thus demonstrate an Aire-expressing plasma cell subset in the BM capable to promote peripheral tolerance by ectopically expressing tissue-restricted self-antigens and generating pTregs.
Project description:The transcription factor CTCF appears indispensable in defining topologically associated domain boundaries and maintaining chromatin loop structures within these domains, supported by numerous functional studies. However, acute depletion of CTCF globally reduces chromatin interactions but does not significantly alter transcription. Here we systematically integrated multi-omics data including ATAC-seq, RNA-seq, WGBS, Hi-C, Cut&Run, CRISPR-Cas9 survival dropout screening, time-solved deep proteomic and phosphoproteomic analyses in cells carrying auxin-induced degron at endogenous CTCF locus. Acute CTCF protein degradation markedly rewired genome-wide chromatin accessibility. Increased accessible chromatin regions were largely located adjacent to CTCF-binding sites at promoter regions and insulator sites and were associated with enhanced transcription of nearby genes. In addition, we used CTCF-associated multi-omics data to establish a combinatorial data analysis pipeline to discover CTCF co-regulatory partners in regulating downstream gene expression. We successfully identified 40 candidates, including multiple established partners (i.e., MYC) supported by all layers of evidence. Interestingly, many CTCF co-regulators (e.g., YY1, ZBTB7A) that have evident alterations of respective downstream gene expression do not show changes at their expression levels across the multi-omics measurements upon acute CTCF loss, highlighting the strength of our system to discover hidden co-regulatory partners associated with CTCF-mediated transcription. This study highlights CTCF loss rewires genome-wide chromatin accessibility, which plays a critical role in transcriptional regulation