ICER/CREM-mediated transcriptional attenuation of IL-2 its role in suppression by regulatory T cells (original) (raw)
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European Journal of Immunology, 2007
Here, we report that inducible cAMP early repressor/cAMP response element modulator (ICER/CREM) is induced early in CD25 + CD4 + regulatory T cell (T R ) assays mainly in activated Foxp3effector T cells and this induction correlates with sharp decrease in number of IL-2-expressing T cells. Importantly, RNAi targeting of ICER/CREM in responder CD25 -CD4 + T cells antagonizes T R -mediated suppression. Moreover, forced expression of Foxp3 in naive CD25 -T cells induces constitutive expression of ICER/ CREM in T cells with a regulatory phenotype. Foxp3 facilitates expression of ICER/ CREM both in Foxp3 transductants as well as CD25responder T cells suggesting that induction of T R function in suppression assays may utilize contact-dependent interaction. Indeed, CTLA-4 blockade or use of B7-deficient CD25responder T cells prevents ICER/CREM accumulation and leads to the rescue of IL-2 expression. Therefore, we propose that CTLA-4 binding to B7 ligands expressed on activated ligandbearing Foxp3effector T cells results in ICER/CREM-mediated transcriptional attenuation of IL-2. Collectively, these data suggest that Foxp3 expression in T R cells imposes suppression in contact-dependent fashion by induction of constitutive ICER/ CREM expression in activated CD25 + Foxp3 -T cell effectors thus preventing them from producing IL-2.
Suppression of T-cell responsiveness by inducible cAMP early repressor (ICER)
Journal of leukocyte biology, 2001
Depending on the nature of the costimulation of T lymphocytes, expression of regulatory cytokines and chemokines is either susceptible or resistant to cyclic AMP (cAMP)-mediated inhibition. Our data show that cAMP-mediated inhibition of endogenously expressed cytokines, which is characteristic for T helper (Th) 1- and Th 2-like phenotypes, correlates with the induction of a potent transcriptional repressor, inducible cAMP early repressor (ICER), in both subsets of T cells activated under conditions of suboptimal interleukin-2 (IL-2) expression. Importantly, Th-specific expression of certain chemokines is also susceptible to cAMP-mediated transcriptional attenuation. To determine whether ICER per se, rather than forskolin-mediated elevation of intracellular cAMP, is responsible for the observed inhibitory effect, we generated transgenic mice expressing ICER under the control of a lymphocyte-specific lck promoter. On stimulation, transgenic thymocytes overexpressing ICER exhibited red...
Cyclic AMP underpins suppression by regulatory T cells
European Journal of Immunology, 2012
APCs, fine-tuning suppression. These cAMP-driven nTreg-cell suppression mechanisms are the focus of this review. Keywords: CD4 + T cells r Costimulatory molecules r Gene regulation r Regulatory T (Treg) cells r Signal transduction expressed on regulatory T cells mediates immune suppression. J. Exp. Med. 2007. 204: 1257-1265. 73 Kuczma, M., Lee, J. R. and Kraj, P., Connexin 43 signaling enhances the generation of Foxp3+ regulatory T cells. J. Immunol. 2011. 187: 248-257. Abbreviations: CREM: cAMP-response modulator · GJIC: gap junction intercellular communication · ICER: inducible cAMP early repressor · IDO: indoleamine 2,3-dioxygenase. sf: scurfy
Proceedings of the National Academy of Sciences, 2011
Inducible cAMP early repressor (ICER) is a transcriptional repressor, which, because of alternate promoter use, is generated from the 3′ region of the cAMP response modulator (Crem) gene. Its expression and nuclear occurrence are elevated by high cAMP levels in naturally occurring regulatory T cells (nTregs). Using two mouse models, we demonstrate that nTregs control the cellular localization of ICER/CREM, and thereby inhibit IL-2 synthesis in conventional CD4 + T cells. Ablation of nTregs in depletion of regulatory T-cell (DEREG) mice resulted in cytosolic localization of ICER/CREM and increased IL-2 synthesis upon stimulation. Direct contacts between nTregs and conventional CD4 + T cells led to nuclear accumulation of ICER/CREM and suppression of IL-2 synthesis on administration of CD28 superagonistic (CD28SA) Ab. In a similar way, nTregs communicated with B cells and induced the cAMPdriven nuclear localization of ICER/CREM. High levels of ICER suppressed the induction of nuclear factor of activated T cell c1 (Nfatc1) gene in T cells whose inducible Nfatc1 P1 promoter bears two highly conserved cAMP-responsive elements to which ICER/ CREM can bind. These findings suggest that nTregs suppress T-cell responses by the cAMP-dependent nuclear accumulation of ICER/ CREM and inhibition of NFATc1 and IL-2 induction. adenosin 3′,5′-cyclic monophospate | transcription | lymphocytes
The cAMP response element modulator (CREM) regulates TH2 mediated inflammation
Oncotarget, 2015
A characteristic feature of allergic diseases is the appearance of a subset of CD4+ cells known as TH2 cells, which is controlled by transcriptional and epigenetic mechanisms. We aimed to analyze the role of CREM, a known transcriptional activator of T cells, with regard to TH2 responses and allergic diseases in men and mice. Here we demonstrate that T cells of asthmatic children and PBMCs of adults with atopy express lower mRNA levels of the transcription factor CREM compared to cells from healthy controls. CREM deficiency in murine T cells results in enhanced TH2 effector cytokines in vitro and in vivo and CREM-/- mice demonstrate stronger airway hyperresponsiveness in an OVA-induced asthma model. Mechanistically, both direct CREM binding to the IL-4 and IL-13 promoter as well as a decreased IL-2 dependent STAT5 activation suppress the TH2 response. Accordingly, mice selectively overexpressing CREMα in T cells display decreased TH2 type cytokines in vivo and in vitro, and are prot...
Suppression of T cell function: a potential role for transcriptional repressor ICER
Journal of leukocyte biology, 2000
In this article, we review the inducible cAMP early repressor (ICER) and its possible critical involvement in modulation of T cell responsiveness by its capacity to transcriptionally attenuate interleukin-2 (IL-2) gene expression. It seems clear that the failure to produce the IL-2 is an important determinant of anergy induction. It is important that the CD28-responsive element (CD28RE), a composite DNA binding element consisting of NFAT and cyclic AMP-responsive (CRE)-like motifs in position of -160 of IL-2 promoter has the high affinity for ICER binding as well as NFAT/ICER complex formation. Moreover, CD28RE with adjacent DNA sequences was also shown to be essential for conferring anergy in T lymphocytes. Because ICER does not possess a transactivation domain required for the recruitment of CBP/p300, the binding of ICER to CD28RE and/or composite motifs containing CRE-like DNA motifs may lead to uncoupling of CBP/p300 thus extinguishing IL-2 expression as well as expression of nu...
Biochemical Journal, 2013
cAMP signalling is both a major pathway as well as a key therapeutic target for inducing immune tolerance and is involved in Treg cell (regulatory T-cell) function. To achieve potent immunoregulation, cAMP can act through several downstream effectors. One proposed mechanism is that cAMP-mediated suppression, including immunosuppression by Treg cells, results from activation of PKA (protein kinase A) leading to the induction of the transcription factor ICER (inducible cAMP early repressor). In the present study, we examined CD4+CD25− Teff cell (effector T-cell) and CD4+CD25+ Treg cell immune responses in Crem (cAMP-response-element modulator) gene-deficient mice which lack ICER (Crem−/−/ICER-deficient mice). ICER deficiency did not significantly alter the frequency or number of Treg cells and Teff cells. Treg cells or a pharmacological increase in cAMP suppressed Teff cells from Crem+/+ and Crem−/−/ICER-deficient mice to an equivalent degree, demonstrating that ICER is dispensable in...