T-helper (Th) lineages have been generated in vitro by activating CD4 cells with anti-CD3/CD28 antibodies during polarization. Physiologically, however, the generation of Th lineages is by activation with the specific antigen presented by antigen-presenting cells (APC). Here, we used TCR-transgenic mice to compare the phenotypes of Th1, Th9 and Th17 lineages when generated by either one of the two activation modes. Lineage Th cells specific against hen egg lysozyme (HEL), were adoptively transferred into recipient mice transgenically expressing HEL in their lens. Remarkable differences were found between lineages of Th1, Th9, or Th17, generated by either one of the two modes in their capacities to migrate to and proliferate in the recipient spleen and, importantly, to induce inflammation in the recipient mouse eyes. Substantial differences were also observed between the lineage pairs in their transcript expression profiles of certain chemokines and chemokine receptors. Surprisingly, however, close similarities were observed between the transcript expression profiles of lineages of the three phenotypes, activated by the same mode. Furthermore, Th cell lineages generated by the two activation modes differed considerably in their pattern of gene expression, as monitored by microarray analysis, but exhibited commonality with lineages of other phenotypes generated by the same activation mode. This study thus shows that (i) Th lineages generated by activation with anti-CD3/CD28 antibodies differ from lineages generated by antigen/APC and (ii) the mode of activation determines to a large extent the expression profile of major transcripts
Phenotypes of Th lineages generated by the commonly used activation with anti-CD3/CD28 antibodies differ from those generated by the physiological activation with the specific antigen.
Specimen part, Treatment
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Transcription factor achaete-scute homologue 2 initiates follicular T-helper-cell development.
Specimen part
View SamplesMultipotential nave CD4+ T cells differentiate into distinct lineages including T helper 1 (Th1), Th2, Th17, and inducible T regulatory (iTreg) cells. The remarkable diversity of CD4+ T cells begs the question whether the observed changes reflect terminal differentiation with heritable epigenetic modifications or plasticity in T cell responses. We generated genome-wide histone H3 lysine 4 (H3K4) and lysine 27 (H3K27) trimethylation maps in nave, Th1, Th2, Th17, iTreg, and natural (n)Treg cells. We found that although modifications of signature cytokine genes (Ifng, Il4, and Il17) partially conform to the expectation of lineage commitment, critical transcription factors such as Tbx21 exhibit a broad spectrum of epigenetic states, consistent with our demonstration of T-bet and IFN-gamma induction in nTreg cells. Our data suggest an epigenetic mechanism underlying the specificity and plasticity of effector and regulatory T cells and also provide a framework for understanding complexity of CD4+ T helper cell differentiation.
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View SamplesCD4+ T cells that selectively produce interleukin (IL)-17, are critical for host defense and autoimmunity1-4. Crucial for T helper17 (Th17) cells in vivo5,6, IL-23 has been thought to be incapable of driving initial differentiation. Rather, IL-6 and transforming growth factor (TGF)-1 have been argued to be the factors responsible for initiating specification7-10. Herein, we show that Th17 differentiation occurs in the absence of TGF- signaling. Neither IL-6 nor IL-23 alone efficiently generated Th17 cells; however, these cytokines in combination with IL-1 effectively induced IL-17 production in nave precursors, independently of TGF-. Epigenetic modification of the Il17a/Il17f and Rorc promoters proceeded without TGF-1, allowing the generation of cells that co-expressed Rort and T-bet. T-bet+Rort+ Th17 cells are generated in vivo during experimental allergic encephalomyelitis (EAE), and adoptively transferred Th17 cells generated with IL-23 in the absence of TGF-1 were more pathogenic in this experimental disease. These data suggest a new model for Th17 differentiation. Consistent with genetic data linking the IL23R with autoimmunity, our findings re-emphasize the role of IL-23 and therefore have important implications for the development of new therapies.
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Treatment
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Hypomethylation of the IL17RC promoter associates with age-related macular degeneration.
Age, Specimen part, Disease, Cell line
View SamplesIn autoimmune diseases, accumulation of activated leukocytes correlates with inflammation and disease progression, and therefore, disruption of leukocyte trafficking is an active area of research. The protein kinase Tpl2 (MAP3K8) regulates leukocyte inflammatory responses and is also being investigated for therapeutic inhibition during autoimmunity. Herein, we addressed the contribution of Tpl2 to the regulation of macrophage chemokine and chemokine receptor expression and subsequent migration in vivo using a mouse model of Tpl2 ablation. We found that gene expression of the chemokine ligands CCL2, CCL7, CXCL2, and CXCL3 as well as the chemokine receptors CCR1 and CCR5 were reduced in macrophages from the bone marrow and peritoneal cavities of tpl2-/- mice following stimulation with LPS. LPS stimulation repressed chemokine receptor expression of CCR1, CCR2 and CCR5. Notably, LPS-induced repression of CCR1 and CCR5 was significantly enhanced in Tpl2-deficient macrophages and was observed to be dependent upon Erk activation and independent of PI3K and mTOR signaling. Consistent with alterations in chemokine and chemokine receptor expression, tpl2-/- macrophages were defective in trafficking to the peritoneal cavity following thioglycollate-induced inflammation. Overall, this study demonstrates a Tpl2-dependent mechanism for macrophage expression of both chemokine receptors and their ligands and provides further insight into how Tpl2 inhibition may disrupt inflammatory networks in vivo.
Tumor progression locus 2 (Tpl2) kinase promotes chemokine receptor expression and macrophage migration during acute inflammation.
Treatment
View SamplesIn immune responses, activated T cells migrate to B cell follicles and develop to T follicular helper (Tfh) cells, a new subset of CD4+ T cells specialized in providing help to B lymphocytes in the induction of germinal centers 1-3. Although Bcl6 has been shown to be essential in Tfh cell function, it may not regulate the initial migration of T cells 4 or the induction of Tfh program as exampled by CXCR5 upregulation 5. Here, we show that the Achaete-Scute homologue 2 (Ascl2) gene that encodes a basic helix-loop-helix (bHLH) transcription factor 6, is selectively upregulated in its expression in Tfh cells. Ectopic expression of Ascl2 uniquely upregulates CXCR5 but not Bcl6 and downregulates CCR7 expression in T cells in vitro and accelerates T cell migration to the follicles and Tfh cell development in vivo. Combined transcriptome profiling and genome-wide occupancy analysis indicate that Ascl2 directly regulates Tfh-related genes while inhibits expression of Th1 and Th17 genes. Acute deletion of Ascl2 as well as blockade of its function with the Id3 protein in peripheral CD4+ T cells results in a failure in Tfh cell development and the germinal center response. Conversely, mutation of Id3, known to cause antibody-mediated autoimmunity, greatly enhances Tfh cell generation. Thus, Ascl2 critically and directly initiates Tfh cell development.
Transcription factor achaete-scute homologue 2 initiates follicular T-helper-cell development.
Specimen part
View SamplesT follicular helper (Tfh) cells play a pivotal role in germinal center reactions, which requires Bcl6 transcription factor. To analyze their relationships with other effector T cell lineages and their stability in vivo, we developed and analyzed a new Bcl6 reporter mouse alone or together with other lineage reporter systems. Assisted with genome-wide transcriptome analysis, we show substantial plasticity of T cell differentiation in the early phase of immune response. At this stage, CXCR5 appears to be expressed in a Bcl6-independent manner. Once Bcl6 is highly expressed, Tfh cells can persist in vivo and some of them develop into memory cells. Together, our results indicate Bcl6 as a bona fide marker for Tfh polarized program.
Bcl6 expression specifies the T follicular helper cell program in vivo.
Sex, Specimen part
View SamplesAge related macular degeneration (AMD) is the leading cause of irreversible blindness in the elderly population worldwide. While recent studies have demonstrated strong genetic associations of single nucleotide polymorphisms within a number of genes and AMD, other modes of regulation are also likely to play a role in its aetiology. We undertook DNA methylation microarray analysis on monozygotic and dizygotic twins who were discordant for AMD and identified methylated IL17RC promoters as being present only in non-AMD control individuals rather than in AMD patients. We validated this finding of a significantly decreased level of methylation on the IL17RC promoter in AMD siblings as well as in a case control study involving 202 genetically unrelated AMD patients and 96 controls (95% CI, 0.03-0.17, P=3.1x10-8). Further, we showed that hypomethylation of the IL17RC promoter in AMD patients led to an elevated expression of its protein and mRNA in peripheral blood as well as in the retina and choroid, suggesting that the DNA methylation pattern and expression of IL17RC may potentially serve as a biomarker for the diagnosis of AMD and likely plays a role in disease pathogenesis.
Hypomethylation of the IL17RC promoter associates with age-related macular degeneration.
Specimen part, Cell line
View SamplesFurin is a proprotein convertase induced in activated T cells, reported to processes the anti-inflammatory cytokine TGFb-1. Herein, we show that conditional deletion of furin in T cells allowed for normal T cell development but impaired the function of regulatory T cells and effector cells, which produced less TGFb-1. Furin-deficient Treg cells, were less protective in a T cell transfer colitis model and failed to induce Foxp3 in normal T cells. Furin-deficient effector cells were inherently overly active and were resistant to suppressive activity of wild-type Tregs. Thus, our results indicate that furin is indispensable in maintaining peripheral tolerance, which is due, at least in part, to its nonredundant, essential function in regulating TGFb-1 production. Targeting furin has emerged as a strategy in malignant and infectious disease. The current work suggests that inhibiting furin might activate immune responses, but may result in a breakdown in peripheral tolerance.
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