Project description:Regulatory T cells (Tregs) are critical for regulating immunopathogenic responses in a variety of infections, including infection of mice with JHMV, a neurotropic coronavirus that causes immune-mediated demyelinating disease. While virus-specific Tregs are known to mitigate disease in this infection by suppressing pathogenic effector T cell responses of the same specificity, it is unclear if these virus-specific Tregs form memory populations and persist similar to their conventional T cell counterparts of the same epitope specificity. Using congenically labeled JHMV-specific Tregs, we found that virus-specific Tregs persist long-term after infection, through at least 180 days post-infection. We additionally demonstrate that these cells are better able to proliferate after infection than naïve Tregs of the same specificity, further suggesting that these cells differentiate into memory Tregs upon encountering cognate antigen. Together, these data suggest that virus-specific Tregs are able to persist long-term in the absence of viral antigen as memory Tregs.
Project description:This study evaluated changes in gene expression upon IL-7 treatment in human naive and memory Treg. CD4+CD25+CD127low naïve and memory Treg were isolated from fresh PBMC and separately stimulated with ?CD3?/CD28 coupled beads (Invitrogen-Dynal) at a 1:10 bead/T cell ratio, treated with or without 10 ng/ml of rhIL-7 (R&D Systems) for 16 hours. qPCR gene expression profiling of CD4+CD25+CD127low naïve and memory Treg obtained from 2 separate donors. Cell lysates were prepared separately from the 2 donors and pooled prior to RNA extraction.
Project description:The transcription factor Foxp3 is indispensible for the differentiation and function of regulatory T cells (Treg cells). To gain insights into the molecular mechanisms of Foxp3 mediated gene expression we purified Foxp3 complexes and explored their composition. Biochemical and mass-spectrometric analyses revealed that Foxp3 forms multi-protein complexes of 400-800 kDa or larger and identified 361 associated proteins ~30% of which are transcription-related. Foxp3 directly regulates expression of a large proportion of the genes encoding its co-factors. Reciprocally, some transcription factor partners of Foxp3 facilitate its expression. Functional analysis of Foxp3 cooperation with one such partner, Gata3, provided further evidence for a network of transcriptional regulation afforded by Foxp3 and its associates to control distinct aspects of Treg cell biology. Gene expression profile of Treg specific knock-out of Gata3 vs. their littermate controls were analyzed to gain insight into Gata3 dependendent genes in Treg cells. Treg cells (CD4+CD25+YFP+) sorted from Gata3F/FFoxp3YFP-Cre and Gata3F/+Foxp3YFP-Cre mice (three mice in each group) followed by microarray analyses.
Project description:Regulatory T (Treg) cells can facilitate transplant tolerance and attenuate autoimmune- and inflammatory diseases. Therefore, it is clinically relevant to stimulate Treg cell expansion and function in vivo and to create therapeutic Treg cell products in vitro. We report that TNF receptor 2 (TNFR2) is a unique costimulus for naïve, thymus-derived (t)Treg cells from human blood that promotes their differentiation into non-lymphoid tissue (NLT)-resident effector Treg cells, without Th-like polarization. In contrast, CD28 costimulation maintains a lymphoid tissue (LT)-resident Treg cell phenotype. We base this conclusion on transcriptome and proteome analysis of TNFR2- and CD28-costimulated CD4+ Treg cells and conventional T (Tconv) cells, followed by bioinformatic comparison with published transcriptomic Treg cell signatures from NLT and LT in health and disease, including autoimmunity and cancer. These analyses illuminate that TNFR2 costimulation promotes Treg cell capacity for survival, migration, immunosuppression and tissue regeneration. Functional studies confirmed improved migratory ability of TNFR2-costimulated tTreg cells. Flow cytometry validated the presence of the TNFR2-driven Treg cell signature in effector/memory Treg cells from the human placenta as opposed to blood. Thus, TNFR2 can be exploited as driver of NLT-resident Treg cell differentiation for adoptive cell therapy or antibody-based immunomodulation in human disease.
Project description:Changes in Treg function are difficult to quantify due to the lack of Treg-exclusive markers in humans and the complexity of functional experiments. We sorted naive and memory human Tregs and conventional T cells, and identified genes that identify human Tregs regardless of their state of activation. We developed this Treg signature using Affymetrix human genome U133A 2.0 microarrays. To generate Tregs and Tconvs in multiple states of activation, naïve (CD4+CD25hiCD45RA+) and memory (CD4+CD25hiCD45RA-) Tregs, and naïve (CD4+CD25-CD45RA+) and memory (CD4+CD25-CD45RA-) Tconvs were sorted from blood of 7 healthy adults and RNA was isolated ex vivo or after stimulation for 40h, promoting activation-induced FOXP3 in Tconvs. The gene-expression profile of the eight cell subsets was analyzed. 7 adult healthy control samples were sorted into 4 subsets: naïve (CD4+CD25hiCD45RA+) and memory (CD4+CD25hiCD45RA-) Tregs, and naïve (CD4+CD25-CD45RA+) and memory (CD4+CD25-CD45RA-) Tconvs. These were used for RNA ex vivo and after 40h stimulation with anti-CD3/CD28 beads to induce an activation phenotype.
Project description:The transcription factor Foxp3 is indispensible for the differentiation and function of regulatory T cells (Treg cells). To gain insights into the molecular mechanisms of Foxp3 mediated gene expression we purified Foxp3 complexes and explored their composition. Biochemical and mass-spectrometric analyses revealed that Foxp3 forms multi-protein complexes of 400-800 kDa or larger and identified 361 associated proteins ~30% of which are transcription-related. Foxp3 directly regulates expression of a large proportion of the genes encoding its co-factors. Reciprocally, some transcription factor partners of Foxp3 facilitate its expression. Functional analysis of Foxp3 cooperation with one such partner, Gata3, provided further evidence for a network of transcriptional regulation afforded by Foxp3 and its associates to control distinct aspects of Treg cell biology. Gene expression profile of Treg specific knock-out of Gata3 vs. their littermate controls were analyzed to gain insight into Gata3 dependendent genes in Treg cells.
Project description:The inflammasome initiates innate defense and inflammatory response by activating caspase-1 and pyroptotic cell death in myeloid cells1,2. It is comprised of an innate immune receptor/effector, pro-caspase-1 and a common adaptor molecule, ASC (apoptotic speck-containing protein with a CARD). Consistent with their pro-inflammatory function, inflammasome components including caspase-1, ASC and NLRP3, are known to exacerbate autoimmunity during experimental autoimmune encephalomyelitis (EAE) by enhancing IL-1 and IL-18 secretion in myeloid cells3-6. Here we show an unexpected function of a DNA-binding inflammasome effector, AIM2 (Absent in Melanoma 2)7-10, in restraining autoimmunity by performing EAE in both whole body and Treg-specific deletion of Aim2–/– mice. AIM2 is highly expressed by human and mouse Treg cells and it is essential to attenuate EAE. RNA-seq, biochemical and metabolic analyses revealed that AIM2 attenuates mTOR, Myc and immune-metabolic functions in both Treg cells isolated in vivo and Treg cells induced in vitro with TGF-. Importantly, we found AIM2 physically interacted with RACK1 in Treg cells to facility the PP2A/RACK1/Akt-mTOR signaling, which is identified as a central component downstream of AIM2 that controls Treg cell function and stability. While AIM2 is generally accepted as an inflammasome effector in myeloid cells, this report reveals a previously unappreciated T cell-intrinsic role of AIM2 in maintaining Treg cell function to restrain autoimmunity. This is achieved by diminishing Akt-mTOR signaling to regulate Treg stability under inflammation, and altering immune-metabolism in Treg cells.