Monophosphate Response Element Modulator Research Articles

Inward Rectifier K+ Currents Contribute to the Proarrhythmic Electrical Phenotype of Atria Overexpressing Cyclic Adenosine Monophosphate Response Element Modulator Isoform CREM-IbΔC-X.

BACKGROUNDTransgenic mice (TG) with heart‐directed overexpresion of the isoform of the transcription factor cyclic adenosine monophosphate response element modulator (CREM), CREM‐IbΔC‐X, display spontaneous atrial fibrillation (AF) and action potential prolongation. The remodeling of the underlying ionic currents remains unknown. Here, we investigated the regulatory role of CREM‐IbΔC‐X on the expression of K+ channel subunits and the corresponding K+ currents in relation to AF onset in TG atrial myocytes.METHODS AND RESULTSECG recordings documented the absence or presence of AF in 6‐week‐old (before AF onset) and 12‐week‐old TG (after AF onset) and wild‐type littermate mice before atria removal to perform patch clamp, contractility, and biochemical experiments. In TG atrial myocytes, we found reduced repolarization reserve K+ currents attributed to a decrease of transiently outward current and inward rectifier K+ current with phenotype progression, and of acetylcholine‐activated K+ current, age independent. The molecular determinants of these changes were lower mRNA levels of Kcnd2/3, Kcnip2, Kcnj2/4, and Kcnj3/5 and decreased protein levels of K+ channel interacting protein 2 (KChIP2 ), Kir2.1/3, and Kir3.1/4, respectively. After AF onset, inward rectifier K+ current contributed less to action potential repolarization, in line with the absence of outward current component, whereas the acetylcholine‐induced action potential shortening before AF onset (6‐week‐old TG mice) was smaller than in wild‐type and 12‐week‐old TG mice. Atrial force of contraction measured under combined vagal‐sympathetic stimulation revealed increased sensitivity to isoprenaline irrespective of AF onset in TG. Moreover, we identified Kcnd2, Kcnd3, Kcnj3, and Kcnh2 as novel CREM‐target genes.CONCLUSIONSOur study links the activation of cyclic adenosine monophosphate response element–mediated transcription to the proarrhythmogenic electrical remodeling of atrial inward rectifier K+ currents with a role in action potential duration, resting membrane stability, and vagal control of the electrical activity.

Are sweetened drinks a gateway to alcohol, opiate and stimulant addiction? Summary of evidence and therapeutic strategies

1. Drinks sweetened with both sugar and artificial additives lead to dopamine release at the nucleus accumbens (NAc) in rat models; the basis of experiences of pleasure in humans, resulting in impulsive binging behaviour at times.2. Evidence from rat models show cross sensitisation between sweetened drinks, alcohol, opiates and stimulants. Therefore, it could be hypothesised that sweetened drinks could be a gateway to multiple substance abuse among humans via ‘alcopops’.3. Identification of an allelic variant of the cyclic adenosine monophosphate responsive element modulator gene (CREM), linking impulsivity and multiple substance abuse, opens up prospects of mass screening to advice on harm reduction.4. Furthermore, therapies involving cannabinoid receptor antagonists and transcranial brain stimulation are being currently investigated; of benefit to limit binge use of sweetened drinks.

Transcription Factor CREM Mediates High Glucose Response in Cardiomyocytes and in a Male Mouse Model of Prolonged Hyperglycemia.

This study aims at investigating the epigenetic landscape of cardiomyocytes exposed to elevated glucose levels. High glucose (30 mM) for 72 hours determined some epigenetic changes in mouse HL-1 and rat differentiated H9C2 cardiomyocytes including upregulation of class I and III histone deacetylase protein levels and activity, inhibition of histone acetylase p300 activity, increase in histone H3 lysine 27 trimethylation, and reduction in H3 lysine 9 acetylation. Gene expression analysis focused on cardiotoxicity revealed that high glucose induced markers associated with tissue damage, fibrosis, and cardiac remodeling such as Nexilin (NEXN), versican, cyclic adenosine 5'-monophosphate-responsive element modulator (CREM), and adrenoceptor α2A (ADRA2). Notably, the transcription factor CREM was found to be important in the regulation of cardiotoxicity-associated genes as assessed by specific small interfering RNA and chromatin immunoprecipitation experiments. In CD1 mice, made hyperglycemic by streptozotoicin (STZ) injection, cardiac structural alterations were evident at 6 months after STZ treatment and were associated with a significant increase of H3 lysine 27 trimethylation and reduction of H3 lysine 9 acetylation. Consistently, NEXN, CREM, and ADRA2 expression was significantly induced at the RNA and protein levels. Confocal microscopy analysis of NEXN localization showed this protein irregularly distributed along the sarcomeres in the heart of hyperglycemic mice. This evidence suggested a structural alteration of cardiac Z-disk with potential consequences on contractility. In conclusion, high glucose may alter the epigenetic landscape of cardiac cells. Sildenafil, restoring guanosine 3', 5'-cyclic monophosphate levels, counteracted the increase of CREM and NEXN, providing a protective effect in the presence of hyperglycemia.

Increased Set1 binding at the promoter induces aberrant epigenetic alterations and up-regulates cyclic adenosine 5'-monophosphate response element modulator alpha in systemic lupus erythematosus.

BackgroundUp-regulated cyclic adenosine 5'-monophosphate response element modulator α (CREMα) which can inhibit IL-2 and induce IL-17A in T cells plays a critical role in the pathogenesis of systemic lupus erythematosus (SLE). This research aimed to investigate the mechanisms regulating CREMα expression in SLE.ResultsFrom the chromatin immunoprecipitation (ChIP) microarray data, we found a sharply increased H3 lysine 4 trimethylation (H3K4me3) amount at the CREMα promoter in SLE CD4+ T cells compared to controls. Then, by ChIP and real-time PCR, we confirmed this result. Moreover, H3K4me3 amount at the promoter was positively correlated with CREMα mRNA level in SLE CD4+ T cells. In addition, a striking increase was observed in SET domain containing 1 (Set1) enrichment, but no marked change in mixed-lineage leukemia 1 (MLL1) enrichment at the CREMα promoter in SLE CD4+ T cells. We also proved Set1 enrichment was positively correlated with both H3K4me3 amount at the CREMα promoter and CREMα mRNA level in SLE CD4+ T cells. Knocking down Set1 with siRNA in SLE CD4+ T cells decreased Set1 and H3K4me3 enrichments, and elevated the levels of DNMT3a and DNA methylation, while the amounts of H3 acetylation (H3ac) and H4 acetylation (H4ac) didn’t alter greatly at the CREMα promoter. All these changes inhibited the expression of CREMα, then augmented IL-2 and down-modulated IL-17A productions. Subsequently, we observed that DNA methyltransferase (DNMT) 3a enrichment at the CREMα promoter was down-regulated significantly in SLE CD4+ T cells, and H3K4me3 amount was negatively correlated with both DNA methylation level and DNMT3a enrichment at the CREMα promoter in SLE CD4+ T cells.ConclusionsIn SLE CD4+ T cells, increased Set1 enrichment up-regulates H3K4me3 amount at the CREMα promoter, which antagonizes DNMT3a and suppresses DNA methylation within this region. All these factors induce CREMα overexpression, consequently result in IL-2 under-expression and IL-17A overproduction, and contribute to SLE at last. Our findings provide a novel approach in SLE treatment.Electronic supplementary materialThe online version of this article (doi:10.1186/s13148-016-0294-2) contains supplementary material, which is available to authorized users.

The expression of cyclic adenosine monophosphate responsive element modulator in rat sertoli cells following seminal extract administration.

Aim:This study aims to determine the effect of seminal vesicle extract on cyclic adenosine monophosphate responsive element modulator (CREM) expression in rat Sertoli cells.Materials and Methods:This study examined the expression of CREM on 20 male rats (Rattus norvegicus) at 4 months of age, weighing 250-300 g. The rats were divided into four groups: K0, KP1, KP2, and KP3. K0 group was injected with 0.2 ml normal saline; KP1 was injected with 25 mg cloprostenol (Prostavet C, Virbac S. A); KP2 and KP3 were injected with 0.2 and 0.4 ml seminal vesicle extract, respectively. The treatments were conducted 5 times within 12-day interval. At the end of the study, the rats were euthanized by cervical dislocation; then, the testicles were necropsied and processed for histology observation using immunohistochemistry staining.Results:CREM expression in rat Sertoli cells was not altered by the administration of either 0.2 or 0.4 ml seminal vesicle extract.Conclusion:The administration of seminal vesicle extract is unable to increase CREM expression in rat Sertoli cells.

Steroidogenesis-related gene expression in the rat ovary exposed to melatonin supplementation

OBJECTIVE:To analyze steroidogenesis-related gene expression in the rat ovary exposed to melatonin supplementation.METHODS:Thirty-two virgin adult female rats were randomized to two groups as follows: the control group GI received vehicle and the experimental group GII received melatonin supplementation (10 µg/night per animal) for 60 consecutive days. After the treatment, animals were anesthetized and the collected ovaries were immediately placed in liquid nitrogen for complementary deoxyribonucleic acid microarray analyses. A GeneChip® Kit Rat Genome 230 2.0 Affymetrix Array was used for gene analysis and the experiment was repeated three times for each group. The results were normalized with the GeneChip® Operating Software program and confirmed through analysis with the secondary deoxyribonucleic acid-Chip Analyzer (dChip) software. The data were confirmed by real-time reverse transcription polymerase chain reaction analysis. Genes related to ovarian function were further confirmed by immunohistochemistry.RESULTS:We found the upregulation of the type 9 adenylate cyclase and inhibin beta B genes and the downregulation of the cyclic adenosine monophosphate response element modulator and cytochrome P450 family 17a1 genes in the ovarian tissue of GII compared to those of the control group.CONCLUSION:Our data suggest that melatonin supplementation decreases gene expression of cyclic adenosine monophosphate, which changes ovarian steroidogenesis.

Cyclic adenosine monophosphate-responsive element modulator alpha overexpression impairs function of hepatic myeloid-derived suppressor cells and aggravates immune-mediated hepatitis in mice.

Molecular factors driving immune-mediated inflammation in the liver are incompletely understood. The transcription factor, cyclic adenosine monophosphate-responsive element modulator alpha (CREMα) can endorse differentiation of T lymphocytes toward T-helper (Th)17 cells, thereby promoting autoimmunity in systemic lupus erythematosus or lung inflammation. To investigate the role of CREMα in liver disease, we subjected transgenic (Tg) mice overexpressing CREMα under control of the CD2 promoter (cremtg mice), which restrains expression mainly to lymphocytes (T, natural killer [NK], and NKT cells), to acute and chronic liver injury models. Already in steady state, Tg CREMα overexpression broadly reduced hepatic immune cell numbers by decreasing their viability, but did not affect immune cell migration or the fibrogenic response to chronic liver injury. Strikingly, cremtg mice developed more severe immune-mediated hepatitis with a higher mortality rate, compared to wild-type (wt) mice, upon concanavalin A (ConA) administration. Unlike in T cells from spleen, CREMα overexpression did not induce a predominant Th17 response in intrahepatic T cells, given that hepatic cremtg CD4+ T cells expressed less interleukin (IL)-17 than wt T cells. Reconstitution of Rag1-/- mice with Crem-/- T cells did not ameliorate ConA hepatitis. Overexpression of CREMα did not influence NK and NKT-cell effector functions either. Interestingly, a subset of monocytic myeloid-derived suppressor cells (MDSCs) also expressed CD2 and CREMα. Cremtg MDSCs isolated from liver expressed reduced inducible nitric oxide synthase and arginase 1 and displayed a reduced T-cell suppressive activity. The adoptive transfer of wt MDSCs was capable of reducing the fulminant immune-mediated liver damage in cremtg mice to wt level. These results suggest compartmental differences of T cell activation pathways between liver and other organs in autoimmunity and define a functional role of CREMα in hepatic monocytic MDSCs for the pathogenesis of immune-mediated liver disease.

TDRD5 is required for retrotransposon silencing, chromatoid body assembly, and spermiogenesis in mice

The Tudor domain-containing proteins (TDRDs) are an evolutionarily conserved family of proteins involved in germ cell development. We show here that in mice, TDRD5 is a novel component of the intermitochondrial cements (IMCs) and the chromatoid bodies (CBs), which are cytoplasmic ribonucleoprotein granules involved in RNA processing for spermatogenesis. Tdrd5-deficient males are sterile because of spermiogenic arrest at the round spermatid stage, with occasional failure in meiotic prophase. Without TDRD5, IMCs and CBs are disorganized, with mislocalization of their key components, including TDRD1/6/7/9 and MIWI/MILI/MIWI2. In addition, Tdrd5-deficient germ cells fail to repress LINE-1 retrotransposons with DNA-demethylated promoters. Cyclic adenosine monophosphate response element modulator (CREM) and TRF2, key transcription factors for spermiogenesis, are expressed in Tdrd5-deficient round spermatids, but their targets, including Prm1/Prm2/Tnp1, are severely down-regulated, which indicates the importance of IMC/CB-mediated regulation for postmeiotic gene expression. Strikingly, Tdrd5-deficient round spermatids injected into oocytes contribute to fertile offspring, demonstrating that acquisition of a functional haploid genome may be uncoupled from TDRD5 function.

Identification of Cyclic Adenosine 3′,5′-Monophosphate Response Element Modulator as an Activator of the Human Sodium/Iodide Symporter Upstream Enhancer

The lack of Na(+)/I(-) symporter (NIS) gene expression in some thyroid cancer patients has been a major hurdle that limits the efficacy of standard radioactive iodide therapy. The molecular mechanism that contributes to low NIS expression is not well understood. Activated NIS gene expression is stimulated by thyroid-stimulating hormone-mediated cAMP/protein kinase A signaling through a NIS upstream enhancer (NUE). The cAMP pathway is also stimulated by forskolin. In the current work, we studied the mechanism of transcriptional activation of NIS in normal thyroid cells and thyroid cancer cells. We identified the cAMP response element modulator (CREM) activator as a new component of the transcription complex that is important for NIS gene expression. The CREM complex is seen in the normal thyroid cells and BRAF (V600E) thyroid cancer cells (BHP 17-10) but is missing in rearranged in transformation/papillary thyroid carcinoma-1 rearrangement thyroid cancer cells (BHP 2-7). This complex is believed to be responsible for the loss of NUE activity and reduced NIS expression in the BHP 2-7 cell line. In BHP 2-7 cells, forskolin stimulated the thyroid-specific transcription factor Pax 8, but CREM activator mRNA did not increase, and this produced a small increase in NUE activity. Ectopic expression of CREM activator enhanced activity of the NUE, indicating that CREM is an essential regulator of NIS gene expression.

Identification of Novel cAMP Responsive Element Modulator (CREM) Isoforms Expressed by Osteoblasts

CREM, the cyclic adenosine monophosphate (cAMP) responsive element modulator, belongs to a multigene family of cAMP-responsive transcription factors. CREM encodes a variety of different isoforms by utilizing four promoters and a complex pattern of alternative messenger ribonucleic acid (mRNA) splicing. We showed previously that parathyroid hormone induces the CREM P2 promoter products known as ICER (inducible cAMP early repressor) in osteoblasts. Herein we report that osteoblasts also express at least 15 CREM transcripts initiated from the P1 promoter, including 7 novel transcripts that result from alternative splicing. It is of interest that we found that CREM-X contains both exon theta1, previously identified only in P3 promoter products, and a new exon termed L, which is located upstream of exon theta1.

Hyperprolactinemia affects spermiogenesis in adult male rats

The mechanisms underlying the antifertility effects of hyperprolactinemia have yet to be established in an appropriate experimental model. Hyperprolactinemia is a known side effect of fluphenazine, a broad spectrum, long-acting phenothiazine known to be dopamine type-D2 receptor antagonist. In our earlier study in adult male rats, we reported that fluphenazine at a dose of 3 mg/kg/day suppressed serum FSH but not testosterone (T) through increasing dopamine (DA) metabolism in the pituitary gland, within 60 days. Fluphenazine treatment affected sperm quality and male rats treated with fluphenazine sired fewer litters. The effects of fluphenazine-induced hyperprolactinemia on sperm quality appeared to be related to reduced FSH. We now report that FSH suppression enhanced the uptake of acridine orange (AO), a DNA intercalating, fluorescent dye by the fluphenazine-treated caput epididymal sperms with concomitant reduction in the uptake of thiol-specific monobromobimane (mBBr) fluorescent dye in vitro, suggesting greater accessibility of DNA intercalating dye to sperm chromatin and reduction in free sperm protein thiols. The concomitant increase in AO and decrease in mBBr fluorescence was suggestive of loose chromatin packaging in caput epididymal sperms after treatment with fluphenazine at 3 mg/kg/day for 60 days. The suppression in levels of protamine (P1) in caput epididymal sperms suggested that chromatin hypocompaction was due to reduced deposition of protamines in sperm chromatin. Reduction in testicular levels of cyclic adenosyl 3', 5' monophosphate response element modulator (CREMtau) and P1 further suggested that reduced deposition was indeed due to reduced synthesis. The concomitant reduction in testicular levels of transition protein 1 (TP1) and transition protein 2 (TP2) also suggested that hypoprotamination was due to reduced synthesis of these proteins crucial for facilitating P1 deposition. The effect appeared to have occurred at the level of translation of CREMtau, since its transcript levels were unaffected whereas those of TP1, TP2 and P1 and protamine were upregulated. The study led to the view that the effects of FSH suppression were manifest on the posttranscriptional modifications of CREMtau, as also on transcript repression of TP1, TP2, P1, which do the RNA- binding proteins bring about. Reduction in FSH did not decrease ABP expression in the testis, which has recently been implicated in the expression of transition protein 1 in vitro. However, a significant reduction was evident after fluphenazine treatment, in the immunoexpression of testicular cAMP, the mediator of FSH effects in the Sertoli cells and putative mediator of ABP effects in the spermatids. The study suggests that fluphenazine-induced hyperprolactinemia suppressed FSH and affected a putative cAMP-dependent mechanism underlying posttranscriptional modification of spermatidal genes involved in chromatin condensation, presumably by reducing the availability/secretion of ABP, a paracrine regulator of spermiogenesis in vitro.

Normal expression of isoforms activating cyclic adenosine monophosphate responsive element modulator in patients with spermatid maturation arrest

To evaluate whether defective cyclic adenosine monophosphate responsive element modulator (CREM) expression is the causative factor of spermatid maturation arrest (SMA). Comparative evaluation of the testicular histology in patients with SMA or normal spermatogenesis. University clinic of andrology. Azoospermic patients undergoing testicular biopsy. None. Expression of CREMtau in quantitative immunohistochemistry analysis of testicular biopsy samples. Regular CREM expression was observed in the tubules with round, but not elongated, spermatids of patients with SMA (n = 9). Quantitative analysis showed that round spermatids of patients with SMA had a staining intensity similar to that observed in controls (n = 7). Lack of spermatid elongation was not due to defective CREM expression. Therefore, CREM did not play a pathogenetic role in the onset of SMA in humans.

Cyclic adenosine 5'-monophosphate response element modulator is responsible for the decreased expression of c-fos and activator protein-1 binding in T cells from patients with systemic lupus erythematosus.

T cells from patients with systemic lupus erythematosus express increased levels of the cAMP response element modulator (CREM) that has been shown to bind to the IL-2 promoter and suppress its activity. In this study, we demonstrate that CREM binds to the proximal promoter of the c-fos proto-oncogene in live systemic lupus erythematosus T cells and represses its expression following stimulation in vitro. Decreased levels of c-fos protein result in decreased AP-1 activity, as determined in shift assays. Blockade of the translation of CREM mRNA with an antisense CREM vector increases the expression of c-fos and the AP-1 activity. The levels of c-fos mRNA vary with disease activity. We conclude that CREM represses the expression of c-fos and limits the activity of the enhancer AP-1. Thus, CREM is involved indirectly in the modulation of transcriptional regulation of multiple genes including IL-2.

Effects Of Exogenous Testosterone On Testicular Function During The Chronic Phase Of Spinal Cord Injury: Dose Effects On Spermatogenesis And Sertoli Cell And Sperm Function

lntroduction: Exogenaustestosterone has been shown to attenuate spinal cord injury (SCI)-related regression of spermatogenesis in the rat The current experiment investigated the effects of exogenaus testosterone in testicular and sperm functions in the rat du ring the chronic phase of SCI.Methods: Chronic SCI rats were given subcutaneous implants of testosterone-filled silastic capsules (TC). Northern blot cDNA hybridization was used to measure testicular Ieveis of Sertoli cell- and germ cell-specific transcripts. Western blot and immunohistochemistry were used to determine protein Ievei and cellular localization , respectively, of cyclic adenosine monophosphate-responsive element modulator (CREM) in the testes. Flow cytometry was used to determine sperm viability and mitochondrial potential.Results: Spontaneaus restoration of spermatogenesis occurred in 7 of the 8 untreated SCI rats. Although exogenaus testosterone restored complete spermatogenesis in all SCI rats, regressed seminiferous epithelium remained in 30% to 70% of tubular cross sections in these rats. These effects were associated with altered responses of germ cell-specific mRNA transcripts to exogenaus testosterone, and abnormal cellular distribution of CREM. Sperm of untreated SCI rats exhibited lowered motility, viability, and mitochondrial potential. Implantation of 1 0 cm of TC worsened sperm motility in sham control and SCI rats, but restored sperm viability and mitochondrial potential in SCI rats.Conclusion: Administration of exogenaus testosterone to SCI rats during the chronic phase of injury failed to facilitate spermatogenic restoration over that achieved in untreated SCI rats. Abnormalities in postmeiotic spermatogenic differentiation could contribute to these effects, and perhaps the production of sperm with abnormal morphology and/or functions during the chronic phase of SCI.

Spinal cord contusion impairs sperm motility in the rat without disrupting spermatogenesis.

Our previous studies demonstrated various abnormalities in spermatogenesis after spinal cord injury (SCI) in cord-transected rats. In this study, we examined whether abnormalities in spermatogenesis in SCI rats were related to the degree of SCI. We used spinal cord-contused (SCC) rats as a model. Adult male Sprague-Dawley rats were subjected to various degrees of cord contusion caused by the weight of a rod dropped from different heights (12.5, 25, 50, and 75 mm) using a New York University IMPACTOR. Testicular histology revealed persistent complete spermatogenesis in all SCC rats 4, 8, or 14 weeks after cord contusion regardless of the extent of SCI. Northern blot complementary DNA (cDNA) hybridization revealed transient but significant decreases in the levels of Sertoli cell-specific transcripts in SCC rats. In addition, levels of messenger RNA (mRNA) transcripts for germ cell-specific transition protein-2 and protamine-1 were consistently decreased in these rats. Such effects were related to the height of the weight drop and were associated with reduced levels of mRNA for cyclic adenosine monophosphate (cAMP) responsive element modulator (CREM). These results demonstrated specific effects of SCI on spermiogenesis and were consistent with altered cAMP signaling in testicular cells after SCI. Sperm motility was also significantly decreased in SCC rats and was related to the height of weight drop. Normal sperm motility recovered only in those rats injured by weight drop from 12.5- and 25-mm heights. In summary, current results demonstrate persistent abnormalities in spermiogenesis and sperm motility in rats that suffered spinal cord contusion by weight drop. Such effects were related to the height of the weight drop and thus to the extent of SCI.

Rewiring the T-cell: signaling defects and novel prospects for the treatment of SLE

Activation of T cells from patients with systemic lupus erythematosus (SLE) leads to increased signaling responses, detected by increased calcium and protein tyrosine phosphorylation patterns. This overexcitability occurs in spite of decreased levels of T-cell receptor ζ chain. The replacement of the ζ chain by the Fc receptor (FcR) γ chain and the formation of signaling molecule aggregates on the surface of T cells are considered to be responsible for the observed signaling phenotype. Decreased production of the ζ-chain promoter binding form of the transcription factor Elf-1 is responsible for the decreased transcription of the ζ chain gene. In addition, transcription of the interleukin-2 (IL-2) gene is decreased because of the presence of the transcriptional repressor cyclic adenine mono-phosphate (cAMP) response element modulator. Replenishment of the ζ chain and elimination of the repressor by antisense approaches leads to increased expression of IL-2, suggesting that gene therapy approaches might represent tangible modalities in the treatment of human SLE.

The cyclic adenosine 5'-monophosphate response element modulator suppresses IL-2 production in stimulated T cells by a chromatin-dependent mechanism.

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.

Novel leader exons of the cyclic adenosine 3',5'-monophosphate response element modulator (CREM) gene, transcribed from promoters P3 and P4, are highly testis-specific in primates.

Testicular expression of CREM is essential for spermatogenesis in the mouse. From a monkey testis cDNA library we isolated a CREM transcript isoform with a novel 5' exon theta2 which provides at its 3'-end an in-frame ATG to the downstream reading frame. 5'-RACE on human testis cDNA indicated that exon theta2 is > or = 113 bp in size. Moreover, a second novel leader exon, theta1, of > or = 289 bp was identified and encodes a putative open reading frame of 26 amino acids. In-vitro translation and cellular expression of CREM-theta1 and CREM-theta2 splice variants cloned from human testis yielded not only full length proteins but also shorter repressor products resulting from downstream translation initiation. Upon co-transfection, products of CREM-theta2 cDNA repressed protein kinase A-induced activation of a CRE-driven reporter construct. RT-PCR analysis of primate tissues for CREM-theta2 transcripts showed abundant expression in the testis and very low levels or absence from all other tissues tested. CREM-theta1 mRNA was exclusively expressed in the testis. Promoters P3 and P4, flanking exons theta1 and theta2, were cloned and found to be non-responsive to protein kinase A in transfection assays. Furthermore, we show differential activation of P1, P3 and P4 during mouse postnatal testicular development, suggesting cell- and stage-specific regulatory mechanisms for these CREM promoters.

Antisense cyclic adenosine 5'-monophosphate response element modulator up-regulates IL-2 in T cells from patients with systemic lupus erythematosus.

The cAMP response element modulator (CREM) has been shown to bind specifically to the -180 site of the IL-2 promoter in vitro. CREM protein is increased in T cells of patients with systemic lupus erythematosus (SLE), and it has been considered responsible for the decreased production of IL-2. In this work we show that transcriptional up-regulation is responsible for the increased CREM protein levels and that CREM binds to the IL-2 promoter in live SLE T cells. Suppression of the expression of CREM mRNA and protein by an antisense CREM plasmid, which was force expressed in SLE T cells by electroporation, resulted in decreased CREM protein binding to the IL-2 promoter and increased expression of IL-2 mRNA and protein. Our data demonstrate that antisense constructs can be used to effectively eliminate the expression of a transcriptional repressor. This approach can be used therapeutically in conditions where increased production of IL-2 is desired.

Novel Cyclic Adenosine 3',5'-Monophosphate (cAMP) Response Element Modulator Isoforms Expressed by Two Newly Identified cAMP-Responsive Promoters Active in the Testis

Novel Cyclic Adenosine 3',5'-Monophosphate (cAMP) Response Element Modulator Isoforms Expressed by Two Newly Identified cAMP-Responsive Promoters Active in the Testis