The Cyclic Adenosine 5′-Monophosphate Response Element Modulator Suppresses IL-2 Production in Stimulated T Cells by a Chromatin-Dependent Mechanism

Abstract

The production of IL-2 is tightly controlled by several transcription factors that bind to the IL-2 promoter. The cAMP response element modulator (CREM) is known to form complexes with CREB and bind to the −180 site of the IL-2 promoter in anergic and in systemic lupus erythematosus T cells. In this study we show that CREM is transcriptionally induced in T cells following stimulation through CD3 and CD28, binds to the IL-2 promoter in vivo, and suppresses IL-2 production. Transfection of an antisense CREM plasmid into T cells blocked the expression and binding of CREM to the IL-2 promoter and the decrease of IL-2 production, which follows the early increase after T cell stimulation with CD3 and CD28. In addition, as assessed by chromatin immunoprecipitation experiments, antisense CREM prevented the binding of protein 300 and cAMP response element binding protein and promoted the acetylation of histones. Antisense CREM also enhanced the accessibility of the IL-2 promoter to endonucleases and prevented the condensation of chromatin in vivo. Our data suggest that upon T cell activation, CREM gradually replaces phosphorylated CREB at the −180 site of the IL-2 promoter. CREM, in turn, binds protein 300 and cAMP response element binding protein, but CREM is unable to activate its histone acetyltransferase activity, which results in condensation of chromatin and down-regulation of IL-2 production.

Tumor suppressor pp32 represses cell growth through inhibition of transcription by blocking acetylation and phosphorylation of histone H3 and initiating its proapoptotic activity

“…The cAMPresponse element (CRE) site of the IL-2 promoter is important for IL-2 production, which recruits transcriptional cofactors and remodels chromatin. 25 To verify whether histone H3 modification influences IL-2 promoter activation, Jurkat cells were stimulated with PMA plus ionomycin for 12 h, then fixed with formaldehyde to crosslink DNA to proteins, sonicated and the DNA-protein complexes were precipitated with specific antibodies for total acetylation and phosphorylation as above. The DNA was extracted and amplified with primers flanking the À180 CRE site of the IL-2 promoter.…”

“…The DNA was amplified with the CRE site of the IL-2 promoter (forward 5 0 -CTA AGT GTG GGC TAA TGT AAC-3 0 and reverse 5 0 -TGT AAA ACT GTG GGG GT-3 0 ) as described. 25 PCR products were run on a 1.5% agarose gel.…”

cAMP response element modulator α controls IL2 and IL17A expression during CD4 lineage commitment and subset distribution in lupus

“…T cells from SLE patients are characterized by severe signaling anomalies resulting in altered cytokine production (14). CREMα has been linked to reduced IL-2 and increased IL-17A expression through diametric trans-regulatory effects on the IL2 and IL17A genes (8,(15)(16)(17). CREMα expression is controlled by trans-activation and trans-repression of the CREM promoter P1 (9,10).…”

Novel molecular targets in the treatment of systemic lupus erythematosus

“…NF-κB nuclear activity has been shown to be diminished, and replenishment of the p65 subunit increases IL-2 production in these cells [16]. A consistent finding in the IL-2 promoter of T cells obtained from patients with lupus has been an imbalance in the CREM/CREB ratio found at the −180 site [17]. The former mainly results because T cells from patients with lupus exhibit abnormally high levels of the inhibitory factor CREM.…”