The Decoy Receptor 3 (DcR3, TNFRSF6B) suppresses Th17 immune responses and is abundant in human cerebrospinal fluid

Immuno-epigenomic analysis identifies attenuated interferon responses in naïve CD4 T cells of adolescents with peanut and multi-food allergy

BACKGROUND

IgE-mediated food allergies have been linked to suboptimal naïve CD4 T (nCD4T) cell activation in infancy, underlined by epigenetic and transcriptomic variation. Similar attenuated nCD4T cell activation in adolescents with food allergy have also been reported, but these are yet to be linked to specific epigenetic or transcriptional changes.

METHODS

We generated genome-wide DNA methylation data in purified nCD4 T cells at quiescence and following activation in a cohort of adolescents (aged 10-15 years old) with peanut allergy (peanut only or peanut + ≥1 additional food allergy) (FA, n = 29), and age-matched non-food allergic controls (NA, n = 18). Additionally, we assessed transcriptome-wide gene expression and cytokine production in these cells following activation.

RESULTS

We found widespread changes in DNA methylation in both NA and FA nCD4T cells in response to activation, associated with the T cell receptor signaling pathway. Adolescents with FA exhibit unique DNA methylation signatures at quiescence and post-activation at key genes involved in Th1/Th2 differentiation (RUNX3, RXRA, NFKB1A, IL4R), including a differentially methylated region (DMR) at the TNFRSF6B promoter, linked to Th1 proliferation. Combined analysis of DNA methylation, transcriptomic data and cytokine output in the same samples identified an attenuated interferon response in nCD4T cells from FA individuals following activation, with decreased expression of several interferon genes, including IFN-γ and a DMR at a key downstream gene, BST2.

CONCLUSION

We find that attenuated nCD4T cell responses from adolescents with food allergy are associated with specific epigenetic variation, including disruption of interferon responses, indicating dysregulation of key immune pathways that may contribute to a persistent FA phenotype. However, we recognize the small sample size, and the consequent restraint on reporting adjusted p-value statistics as limitations of the study. Further study is required to validate these findings.

Inferred Causal Mechanisms of Persistent FMDV Infection in Cattle from Differential Gene Expression in the Nasopharyngeal Mucosa

Foot-and-mouth disease virus (FMDV) can persistently infect pharyngeal epithelia in ruminants but not in pigs. Our previous studies demonstrated that persistent FMDV infection in cattle was associated with under-expression of several chemokines that recruit immune cells. This report focuses on the analysis of differentially expressed genes (DEG) identified during the transitional phase of infection, defined as the period when animals diverge between becoming carriers or terminators. During this phase, Th17-stimulating cytokines (IL6 and IL23A) and Th17-recruiting chemokines (CCL14 and CCL20) were upregulated in animals that were still infected (transitional carriers) compared to those that had recently cleared infection (terminators), whereas chemokines recruiting neutrophils and CD8+ T effector cells (CCL3 and ELR+CXCLs) were downregulated. Upregulated Th17-specific receptor, CCR6, and Th17-associated genes, CD146, MIR155, and ThPOK, suggested increased Th17 cell activity in transitional carriers. However, a complex interplay of the Th17 regulatory axis was indicated by non-significant upregulation of IL17A and downregulation of IL17F, two hallmarks of TH17 activity. Other DEG suggested that transitional carriers had upregulated aryl hydrocarbon receptor (AHR), non-canonical NFκB signaling, and downregulated canonical NFκB signaling. The results described herein provide novel insights into the mechanisms of establishment of FMDV persistence. Additionally, the fact that ruminants, unlike pigs, produce a large amount of AHR ligands suggests a plausible explanation of why FMDV persists in ruminants, but not in pigs.

Global gene expression responses of Atlantic salmon skin to Moritella viscosa

Moritella viscosa is a Gram-negative pathogen that causes large, chronic ulcers, known as winter-ulcer disease, in the skin of several fish species including Atlantic salmon. We used a bath challenge approach to profile the transcriptome responses of M. viscosa-infected Atlantic salmon skin at the lesion (Mv-At) and away from the lesion (Mv-Aw) sites. M. viscosa infection was confirmed through RNA-based qPCR assays. RNA-Seq identified 5212 and 2911 transcripts differentially expressed in the Mv-At compared to no-infection control and Mv-Aw groups, respectively. Also, there were 563 differentially expressed transcripts when comparing the Mv-Aw to control samples. Our results suggest that M. viscosa caused massive and strong, but largely infection site-focused, transcriptome dysregulations in Atlantic salmon skin, and its effects beyond the skin lesion site were comparably subtle. The M. viscosa-induced transcripts of Atlantic salmon were mainly involved in innate and adaptive immune response-related pathways, whereas the suppressed transcripts by this pathogen were largely connected to developmental and cellular processes. As validated by qPCR, M. viscosa dysregulated transcripts encoding receptors, signal transducers, transcription factors and immune effectors playing roles in TLR- and IFN-dependent pathways as well as immunoregulation, antigen presentation and T-cell development. This study broadened the current understanding of molecular pathways underlying M. viscosa-triggered responses of Atlantic salmon, and identified biomarkers that may assist to diagnose and combat this pathogen.

<p>Case–Control Study on <em>TNFRSF6B</em> Gene Polymorphism and Susceptibility to Gastric Cancer in a Chinese Han Population</p>

Purpose

To explore the relationship between rs2297440 and rs2297441 polymorphisms of TNFRSF6B gene and susceptibility to gastric cancer.

Methods

A hospital-based case-control study was conducted. A total of 577 gastric cancer cases and 678 normal controls were recruited. Their genotypes were determined using the SnapShot method.

Results

The smoking rate in the case group (34.49%) was higher than that in the control group (27.29%). For TNFRSF6B rs2297440, among people <62 years old, the risk of gastric cancer in TC people was 1.84 times that in TT people. Among the non-drinking people, the risk of gastric cancer in the CC type was 0.66 times that in the TT+TC type. Among the drinking population, the risk of gastric cancer in the TC type was 1.67 times that in the TT type, and the risk in the TC+CC type was 1.70 times that in the TT type. As for TNFRSF6B rs2297441, in males and non-drinkers, the risk of gastric cancer in the AG type was less than that in the GG type. No matter how old the patient is, the risk of gastric cancer in the AA type was less than that in the AG+GG type.

Conclusion

A correlation exists between smoking and gastric cancer. For TNFRSF6B rs2297440, the TC genotype may be a risk factor for gastric cancer in people <62 years old. In the non-drinking population, the homozygous mutant of CC may be a protective factor for gastric cancer. In the drinking population, TC type may be a risk factor, whereas the TC+CC type dominated by C may be a protective factor. For TNFRSF6B rs2297441, the AG genotype may be a risk factor for gastric cancer in males and non-drinkers. The AA homozygous mutant may be a protective factor for gastric cancer.

Transcriptomic Profiling of the Adaptive and Innate Immune Responses of Atlantic Salmon to Renibacterium salmoninarum Infection

Bacterial Kidney Disease (BKD), which is caused by a Gram-positive, intracellular bacterial pathogen (Renibacterium salmoninarum), affects salmonids including Atlantic salmon (Salmo salar). However, the transcriptome response of Atlantic salmon to BKD remained unknown before the current study. We used a 44K salmonid microarray platform to characterise the global gene expression response of Atlantic salmon to BKD. Fish (~54 g) were injected with a dose of R. salmoninarum (H-2 strain, 2 × 10⁸ CFU per fish) or sterile medium (control), and then head kidney samples were collected at 13 days post-infection/injection (dpi). Firstly, infection levels of individuals were determined through quantifying the R. salmoninarum level by RNA-based TaqMan qPCR assays. Thereafter, based on the qPCR results for infection level, fish (n = 5) that showed no (control), higher (H-BKD), or lower (L-BKD) infection level at 13 dpi were subjected to microarray analyses. We identified 6,766 and 7,729 differentially expressed probes in the H-BKD and L-BKD groups, respectively. There were 357 probes responsive to the infection level (H-BKD vs. L-BKD). Several adaptive and innate immune processes were dysregulated in R. salmoninarum-infected Atlantic salmon. Adaptive immune pathways associated with lymphocyte differentiation and activation (e.g., lymphocyte chemotaxis, T-cell activation, and immunoglobulin secretion), as well as antigen-presenting cell functions, were shown to be differentially regulated in response to BKD. The infection level-responsive transcripts were related to several mechanisms such as the JAK-STAT signalling pathway, B-cell differentiation and interleukin-1 responses. Sixty-five microarray-identified transcripts were subjected to qPCR validation, and they showed the same fold-change direction as microarray results. The qPCR-validated transcripts studied herein play putative roles in various immune processes including pathogen recognition (e.g., tlr5), antibacterial activity (e.g., hamp and camp), regulation of immune responses (e.g., tnfrsf11b and socs1), T-/B-cell differentiation (e.g., ccl4, irf1 and ccr5), T-cell functions (e.g., rnf144a, il13ra1b and tnfrsf6b), and antigen-presenting cell functions (e.g., fcgr1). The present study revealed diverse immune mechanisms dysregulated by R. salmoninarum in Atlantic salmon, and enhanced the current understanding of Atlantic salmon response to BKD. The identified biomarker genes can be used for future studies on improving the resistance of Atlantic salmon to BKD.

Decoy Receptor 3 Promotes Preosteoclast Cell Death via Reactive Oxygen Species-Induced Fas Ligand Expression and the IL-1α/IL-1 Receptor Antagonist Pathway

Purpose

Interleukin-1α (IL-1α) is a potent cytokine that plays a role in inflammatory arthritis and bone loss. Decoy receptor 3 (DCR3) is an immune modulator of monocytes and macrophages. The aim of this study was to investigate the mechanism of DCR3 in IL-1α-induced osteoclastogenesis.

Methods

We treated murine macrophages with DCR3 during receptor activator of nuclear factor kappa Β ligand- (RANKL-) plus IL-1α-induced osteoclastogenesis to monitor osteoclast formation by tartrate-resistant acid phosphatase (TRAP) staining. Osteoclast activity was assessed using a pit formation assay. The mechanisms of inhibition were studied by biochemical analyses, including RT-PCR, immunofluorescent staining, flow cytometry, an apoptosis assay, immunoblotting, and ELISA.

Results

DCR3 suppresses IL-1α-induced osteoclastogenesis in both primary murine bone marrow-derived macrophages (BMM) and RAW264.7 cells as it inhibits bone resorption. DCR3 induces RANKL-treated osteoclast precursor cells to express IL-1α, secretory IL-1ra (sIL-1ra), intracellular IL-1ra (icIL-1ra), reactive oxygen species (ROS), and Fas ligand and to activate IL-1α-induced interleukin-1 receptor-associated kinase 4 (IRAK4). The suppression of DCR3 during RANKL- or IL-1α-induced osteoclastogenesis may be due to the abundant secretion of IL-1ra, accumulation of ROS, and expression of Fas ligand in apoptotic osteoclast precursor cells.

Conclusions

We concluded that there is an inhibitory effect of DCR3 on osteoclastogenesis via ROS accumulation and ROS-induced Fas ligand, IL-1α, and IL-1ra expression. Our results suggested that the upregulation of DCR3 in preosteoclasts might be a therapeutic target in inflammatory IL-1α-induced bone resorption.

Correlations Between Serum Decoy Receptor 3 and Airflow Limitation and Quality of Life in Male Patients with Stable Stage and Acute Exacerbation of COPD

PURPOSE

Serum decoy receptor 3 (DcR3) level increases in chronic inflammatory diseases. The present study aimed to examine serum DcR3 and IL-6 levels in male patients with stable chronic obstructive pulmonary disease (COPD) and acute exacerbation of the disease and correlations between these markers and airflow limitation.

METHODS

We measured serum DcR3 and IL-6 levels in 60 COPD patients [30 stable COPD (SCOPD), and 30 acute exacerbation of COPD (AECOPD)], and 30 control subjects and assessed their correlations with airflow limitation according to the COPD stage indicated by the global initiative for chronic obstructive pulmonary disease (GOLD) criteria, peripheral O₂ saturation (SpO₂), and COPD assessment test (CAT) score. We also tested associations between serum DcR3 levels and COPD patients' clinical parameters.

RESULTS

Both serum DcR3 and IL-6 levels increased with increasing severity of airflow limitation in SCOPD and AECOPD groups (P < 0.01 to 0.001). These markers also increased in patients with AECOPD compared with subjects in SCOPD group in GOLD stages III-IV (P < 0.05 to 0.001). In addition, there was a significant positive correlation between serum DcR3 level and IL-6, CAT score and smoking history (per year).

CONCLUSION

The study revealed that serum DcR3 level elevated with increasing severity of airflow limitation in male COPD patients, particularly in acute exacerbation phase. This increase was associated with a reduced quality of life and increased severity of hypoxia. These results suggest that DcR3 may be associated with the underlying pathophysiology of COPD in male patients.

Profiling the transcriptome response of Atlantic salmon head kidney to formalin-killed Renibacterium salmoninarum

Renibacterium salmoninarum is a Gram-positive, intracellular bacterial pathogen that causes Bacterial Kidney Disease (BKD) in Atlantic salmon (Salmo salar). The host transcriptomic response to this immune-suppressive pathogen remains poorly understood. To identify R. salmoninarum-responsive genes, Atlantic salmon were intraperitoneally injected with a low (5 × 10⁵ cells/kg, Low-Rs) or high (5 × 10⁷ cells/kg; High-Rs) dose of formalin-killed R. salmoninarum bacterin or phosphate-buffered saline (PBS control); head kidney samples were collected before and 24 h after injection. Using 44K microarray analysis, we identified 107 and 345 differentially expressed probes in response to R. salmoninarum bacterin (i.e. High-Rs vs. PBS control) by Significance Analysis of Microarrays (SAM) and Rank Products (RP), respectively. Twenty-two microarray-identified genes were subjected to qPCR assays, and 17 genes were confirmed as being significantly responsive to the bacterin. There was an up-regulation in expression of genes playing putative roles as immune receptors and antimicrobial effectors. Genes with putative roles as pathogen recognition (e.g. clec12b and tlr5) or immunoregulatory (e.g. tnfrsf6b and tnfrsf11b) receptors were up-regulated in response to R.salmoninarum bacterin. Also, chemokines and a chemokine receptor showed opposite regulation [up-regulation of effectors (i.e. ccl13 and ccl) and down-regulation of cxcr1] in response to the bacterin. The present study identified and validated novel biomarker genes (e.g. ctsl1, lipe, cldn4, ccny) that can be used to assess Atlantic salmon response to R. salmoninarum, and will be valuable in the development of tools to combat BKD.

Decoy receptor 3: an endogenous immunomodulator in cancer growth and inflammatory reactions

Decoy receptor 3 (DcR3), also known as tumor necrosis factor receptor (TNFR) superfamily member 6b (TNFRSF6B), is a soluble decoy receptor which can neutralize the biological functions of three members of tumor necrosis factor superfamily (TNFSF): Fas ligand (FasL), LIGHT, and TL1A. In addition to ‘decoy’ function, recombinant DcR3.Fc is able to modulate the activation and differentiation of dendritic cells (DCs) and macrophages via ‘non-decoy’ action. DcR3-treated DCs skew T cell differentiation into Th2 phenotype, while DcR3-treated macrophages behave M2 phenotype. DcR3 is upregulated in various cancer cells and several inflammatory tissues, and is regarded as a potential biomarker to predict inflammatory disease progression and cancer metastasis. However, whether DcR3 is a pathogenic factor or a suppressor to attenuate inflammatory reactions, has not been discussed comprehensively yet. Because mouse genome does not have DcR3, it is not feasible to investigate its physiological functions by gene-knockout approach. However, DcR3-mediated effects in vitro are determined via overexpressing DcR3 or addition of recombinant DcR3.Fc fusion protein. Moreover, CD68-driven DcR3 transgenic mice are used to investigate DcR3-mediated systemic effects in vivo. Upregulation of DcR3 during inflammatory reactions exerts negative-feedback to suppress inflammation, while tumor cells hijack DcR3 to prevent apoptosis and promote tumor growth and invasion. Thus, ‘switch-on’ of DcR3 expression may be feasible for the treatment of inflammatory diseases and enhance tissue repairing, while ‘switch-off’ of DcR3 expression can enhance tumor apoptosis and suppress tumor growth in vivo.

Serum decoy receptor 3 is a biomarker for disease severity in nonatopic asthma patients

BACKGROUND/PURPOSE

Decoy receptor 3 (DcR3), a soluble receptor of the tumor necrosis factor receptor superfamily, is a pleiotropic immunomodulator. The aim of this study was to investigate serum DcR3 levels in atopic and nonatopic asthma patients.

METHODS

The serum DcR3 levels of 70 adults with asthma and 20 healthy controls were determined by enzyme-linked immunosorbent assay (ELISA). The asthma patients were divided into atopic and nonatopic subgroups, based on the presence or absence of immunoglobulin E (IgE) specific to allergen. Correlations between serum DcR3 levels and blood total-eosinophil counts, forced expiratory volume in 1 second (FEV1), FEV1/forced vital capacity (FVC), and Asthma Control Test (ACT) scores were analyzed.

RESULTS

The mean serum DcR3 level was significantly higher in asthma patients than in healthy controls (266.1 ± 60.6 pg/mL vs. 63.7 ± 21.9 pg/mL, p = 0.003), but there was no significant difference between the mean serum DcR3 level of asthma patients with atopy (37 patients) and patients without atopy (33 patients; 298.7 ± 111.2 pg/mL vs. 230.6 ± 38.5 pg/mL, p = 0.064). However, the serum DcR3 level was positively correlated with the total eosinophil count (r = 0.448, p = 0.012) and inversely correlated with the percentages of predicted FEV1, FEV1/FVC, and ACT score (r = 0.409, p = 0.018; r = -0.399, p = 0.021; and r = -0.505, p = 0.003, respectively) in nonatopic asthma patients, but not in atopic patients.

CONCLUSION

High serum DcR3 levels are associated with disease severity in nonatopic asthma patients, which suggests that DcR3 is a potential biomarker that can be used to predict the severity of nonatopic asthma.

Predictive value of decoy receptor 3 in postoperative nosocomial bacterial meningitis

Nosocomial bacterial meningitis requires timely treatment, but what is difficult is the prompt and accurate diagnosis of this disease. The aim of this study was to assess the potential role of decoy receptor 3 (DcR3) levels in the differentiation of bacterial meningitis from non-bacterial meningitis. A total of 123 patients were recruited in this study, among them 80 patients being with bacterial meningitis and 43 patients with non-bacterial meningitis. Bacterial meningitis was confirmed by bacterial culture of cerebrospinal fluid (CSF) culture and enzyme-linked immunosorbent assay (ELISA) was used to detect the level of DcR3 in CSF. CSF levels of DcR3 were statistically significant between patients with bacterial meningitis and those with non-bacterial meningitis (p < 0.001). A total of 48.75% of patients with bacterial meningitis received antibiotic >24 h before CSF sampling, which was much higher than that of non-bacterial meningitis. CSF leucocyte count yielded the highest diagnostic value, with an area under the receiver operating characteristic curve (ROC) of 0.928, followed by DcR3. At a critical value of 0.201 ng/mL for DcR3, the sensitivity and specificity were 78.75% and 81.40% respectively. DcR3 in CSF may be a valuable predictor for differentiating patients with bacterial meningitis from those with non-bacterial meningitis. Further studies are needed for the validation of this study.

Excess LIGHT contributes to placental impairment, increased secretion of vasoactive factors, hypertension, and proteinuria in preeclampsia

Preeclampsia, a prevalent hypertensive disorder of pregnancy, is believed to be secondary to uteroplacental ischemia. Accumulating evidence indicates that hypoxia-independent mediators, including inflammatory cytokines and growth factors, are associated with preeclampsia, but it is unclear whether these signals directly contribute to placental damage and disease development in vivo. We report that LIGHT, a novel tumor necrosis factor superfamily member, is significantly elevated in the circulation and placentas of preeclamptic women compared with normotensive pregnant women. Injection of LIGHT into pregnant mice induced placental apoptosis, small fetuses, and key features of preeclampsia, hypertension and proteinuria. Mechanistically, using neutralizing antibodies specific for LIGHT receptors, we found that LIGHT receptors herpes virus entry mediator and lymphotoxin β receptor are required for LIGHT-induced placental impairment, small fetuses, and preeclampsia features in pregnant mice. Accordingly, we further revealed that LIGHT functions through these 2 receptors to induce secretion of soluble fms-like tyrosine kinase-1 and endothelin-1, 2 well-accepted pathogenic factors in preeclampsia, and thereby plays an important role in hypertension and proteinuria in pregnant mice. Lastly, we extended our animal findings to human studies and demonstrated that activation of LIGHT receptors resulted in increased apoptosis and elevation of soluble fms-like tyrosine kinase-1 secretion in human placental villous explants. Overall, our human and mouse studies show that LIGHT signaling is a previously unrecognized pathway responsible for placental apoptosis, elevated secretion of vasoactive factors, and subsequent maternal features of preeclampsia, and reveal new therapeutic opportunities for the management of the disease.

Orchestrated leukocyte recruitment to immune-privileged sites: absolute barriers versus educational gates

Complex barriers separate immune-privileged tissues from the circulation. Here, we propose that cell entry to immune-privileged sites through barriers composed of tight junction-interconnected endothelium is associated with destructive inflammation, whereas border structures comprised of fenestrated vasculature enveloped by tightly regulated epithelium serve as active and selective immune-skewing gates in the steady state. Based on emerging knowledge of the central nervous system and information from other immune-privileged sites, we propose that these sites are endowed either with absolute endothelial-based barriers and epithelial gates that enable selective and educative transfer of trafficking leukocytes or with selective epithelial gates only.

Multiple sclerosis: the role of cytokines in pathogenesis and in therapies

Multiple sclerosis, the clinical features and pathological correlate for which were first described by Charcot, is a chronic neuroinflammatory disease with unknown etiology and variable clinical evolution. Although neuroinflammation is a descriptive denominator in multiple sclerosis based on histopathological observations, namely the penetration of leukocytes into the central nervous system, the clinical symptoms of relapses, remissions and progressive paralysis are the result of losses of myelin and neurons. In the absence of etiological factors as targets for prevention and therapy, the definition of molecular mechanisms that form the basis of inflammation, demyelination and toxicity for neurons have led to a number of treatments that slow down disease progression in specific patient cohorts, but that do not cure the disease. Current therapies are directed to block the immune processes, both innate and adaptive, that are associated with multiple sclerosis. In this review, we analyze the role of cytokines in the multiple sclerosis pathogenesis and current/future use of them in treatments of multiple sclerosis.

Clinical significance of expression and amplification of the DcR3 gene in pancreatic carcinomas

This study aimed to investigate the clinical significance of expression and amplification of decoy receptor 3 (DcR3) in pancreatic carcinomas (PC). mRNA expression was detected by PQ-PCR, and amplification was determined. DcR3 protein expression was detected by immunohistochemistry and ELISA. Correlations between DcR3 expression and clinical pathological factors were analyzed. The relative amount of DcR3 in PC tissues and non-cancerous tissues showed a statistically significant difference, 21 cases displaying more than two fold DcR3 amplification, while no such amplification was found in normal pancreatic tissues. DcR3 positive cell staining was located in the cytoplasm. The positive rate of DcR3 in PC and non-cancerous tissues showed a significant difference. DcR3 mRNA expression was correlated with clinical staging, size of the tumor, lymph node metastasis and histological staging, while protein expression was correlated with clinical data like tumor size. DcR3 gene amplification only correlated with tumor size. The level of DcR3 in serum of the PC resectable group before operation was 72.2±10.2 pg/ml, showing a significant difference compared to gallbladder carcinoma group (GC) or pancreatic benign tumor (PBT) group (P <0.01). In conclusion, DcR3 amplification is correlated with DcR3 expression in PC tissues, especially those clinical pathological factors which reflect tumor progression. Assessment of DcR3 level in sera of PC patients may be helpful for the early diagnosis and prognostic judgement.

DcR3 binds to ovarian cancer via heparan sulfate proteoglycans and modulates tumor cells response to platinum with corresponding alteration in the expression of BRCA1

BACKGROUND

Overcoming platinum resistance is a major obstacle in the treatment of Epithelial Ovarian Cancer (EOC). In our previous work Decoy Receptor 3 (DcR3) was found to be related to platinum resistance. The major objective of this work was to define the cellular interaction of DcR3 with EOC and to explore its effects on platinum responsiveness.

METHODS

We studied cell lines and primary cultures for the expression of and the cells ability to bind DcR3. Cells were cultured with DcR3 and then exposed to platinum. Cell viability was determined by MTT assay. Finally, the cells molecular response to DcR3 was studied using real time RT-PCR based differential expression arrays, standard RT-PCR, and Western blot.

RESULTS

High DcR3 in the peritoneal cavity of women with EOC is associated with significantly shorter time to first recurrence after platinum based therapy (p = 0.02). None-malignant cells contribute DcR3 in the peritoneal cavity. The cell lines studied do not secrete DcR3; however they all bind exogenous DcR3 to their surface implying that they can be effected by DcR3 from other sources. DcR3s protein binding partners are minimally expressed or negative, however, all cells expressed the DcR3 binding Heparan Sulfate Proteoglycans (HSPGs) Syndecans-2, and CD44v3. DcR3 binding was inhibited by heparin and heparinase. After DcR3 exposure both SKOV-3 and OVCAR-3 became more resistant to platinum with 15% more cells surviving at high doses. On the contrary CaOV3 became more sensitive to platinum with 20-25% more cell death. PCR array analysis showed increase expression of BRCA1 mRNA in SKOV-3 and OVCAR-3 and decreased BRCA1 expression in CaOV-3 after exposure to DcR3. This was confirmed by gene specific real time PCR and Western blot analysis.

CONCLUSIONS

Non-malignant cells contribute to the high levels of DcR3 in ovarian cancer. DcR3 binds readily to EOC cells via HSPGs and alter their responsiveness to platinum chemotherapy. The paradoxical responses seen were related to the expression pattern of HSPGs available on the cells surface to interact with. Although the mechanism behind this is not completely known alterations in DNA repair pathways including the expression of BRCA1 appear to be involved.

Current status of the immunomodulation and immunomediated therapeutic strategies for multiple sclerosis

Multiple sclerosis (MS) is an autoimmune disease of the central nervous system, and CD4(+) T cells form the core immunopathogenic cascade leading to chronic inflammation. Traditionally, Th1 cells (interferon-γ-producing CD4(+) T cells) driven by interleukin 12 (IL12) were considered to be the encephalitogenic T cells in MS and experimental autoimmune encephalomyelitis (EAE), an animal model of MS. Currently, Th17 cells (Il17-producing CD4(+) T cells) are considered to play a fundamental role in the immunopathogenesis of EAE. This paper highlights the growing evidence that Th17 cells play the core role in the complex adaptive immunity of EAE/MS and discusses the roles of the associated immune cells and cytokines. These constitute the modern immunological basis for the development of novel clinical and preclinical immunomodulatory therapies for MS discussed in this paper.

Decoy receptor 3 inhibits renal mononuclear leukocyte infiltration and apoptosis and prevents progression of IgA nephropathy in mice

The progression of IgA nephropathy (IgAN), the most frequent type of primary glomerulonephritis, is associated with high levels of mononuclear leukocyte infiltration into the kidney. These cells consist mainly of T cells and macrophages. Our previous study showed that a decoy receptor 3 (DCR3) gene therapy can prevent the development of a mouse autoimmune glomerulonephritis model by its potent immune modulating effects (Ka SM, Sytwu HK, Chang DM, Hsieh SL, Tsai PY, Chen A. J Am Soc Nephrol 18: 2473-2485, 2007). Here, we tested the hypothesis that DCR3 might prevent the progression of IgAN, an immune complex-mediated primary glomerulonephritis, by inhibiting T cell activation, renal T cell/macrophage infiltration, and protecting the kidney from apoptosis. We used a progressive IgAN (Prg-IgAN) model in B cell-deficient mice, because the mice are characterized by a dramatic proliferation of activated T cells systemically and progressive NF-κB activation in the kidney. We treated the animals with short-term gene therapy with DCR3 plasmids by hydrodynamics-based gene delivery. When the mice were euthanized on day 21, we found that, compared with empty vector-treated (disease control) Prg-IgAN mice, DCR3 gene therapy resulted in 1) systemic inhibition of T cell activation and proliferation; 2) lower serum levels of proinflammatory cytokines; 3) improved proteinuria, renal function, and renal pathology (inhibiting the development of marked glomerular proliferation, crescent formation, glomerulosclerosis, and interstitial inflammation); 5) suppression of T cell and macrophage infiltration into the periglomerular interstitium of the kidney; and 5) a reduction in apoptotic figures in the kidney. On the basis of these findings, DCR3 might be useful therapeutically in preventing the progression of IgAN.

Decoy receptor 3 attenuates collagen-induced arthritis by modulating T cell activation and B cell expansion

OBJECTIVE

To investigate the immune-modulated effects of decoy receptor 3 (DCR3) in an experimental model of rheumatoid arthritis (RA).

METHODS

We delivered DCR3 plasmid into collagen-induced arthritis (CIA) mice using the hydrodynamic method and evaluated the serum level of DCR3 protein by ELISA. After immunization, we assessed disease severity of arthritis incidence, arthritis scores, paw thickness, and means of arthritic limbs, and used hematoxylin and eosin staining to observe synovial hyperplasia. We analyzed numbers of murine splenocytes and inguinal lymphocyte cells, cell populations, and serum proinflammatory cytokines by flow cytometry. We investigated B cell proliferation by carboxyfluorescein succinimidyl ester assay. We evaluated serum levels of total IgG2a and type II collagen-specific IgG and IgG2a using ELISA.

RESULTS

DCR3 expression in sera significantly attenuated disease severity in CIA mice. We found that DCR3 inhibited the volume of inguinal lymph nodes, numbers of CD19+ B cells, and populations of interferon-γ, interleukin 4 (IL-4), IL-17A, and Foxp3-producing CD4+ T cell in vivo. We found that DCR3 inhibited Pam3CSK4 (Toll-like receptor 1/2 ligand)-induced B220+ B cell proliferation in vitro. DCR3 treatment reduced the serum level of IL-6, total IgG2a, and CII-specific IgG2a antibody.

CONCLUSION

We postulated that the protective effects of DCR3 in CIA resulted from modulation of the immune system by maintaining the B/T cell balance and decreasing lymphocyte expansion. We suggest DCR3 as a prophylactic and potential therapeutic agent in the treatment of RA.

Decoy receptor 3: a pleiotropic immunomodulator and biomarker for inflammatory diseases, autoimmune diseases and cancer

Recently, several decoy molecules belonging to tumor necrosis factor receptor superfamily (TNFRSF) have been identified, including decoy receptor 1 (DcR1), decoy receptor 2 (DcR2), and decoy receptor 3 (DcR3). One of the tumor necrosis factor superfamily (TNFSF) members, TNF-related apoptosis-inducing ligand (TRAIL), binds to DcR1 and DcR2, which are membranous receptors with a truncated cytoplasmic domain, thus unable to transduce TRAIL-mediated signaling. In contrast to DcR1 and DcR2, DcR3 is a soluble receptor capable of neutralizing the biological effects of three other TNFSF members: Fas ligand (FasL/TNFSF6/CD95L), LIGHT (TNFSF14) and TNF-like molecule 1A (TL1A/TNFSF15). Since FasL is a potent apoptosis- and inflammation-inducing factor, LIGHT is involved in apoptosis and inflammation, and TL1A is a T cell costimulator and is involved in gut inflammation, DcR3 can be defined as an immunomodulator on the basis of its neutralizing effects on FasL, LIGHT, and TL1A. Initial studies demonstrated that DcR3 expression is elevated in tumors cells; however, later work showed that DcR3 expression is also upregulated in inflammatory diseases, where serum DcR3 levels correlate with disease progression. In addition to its neutralizing effect, DcR3 also acts as an effector molecule to modulate cell function via 'non-decoy' activities. This review focuses on the immunomodulatory effects of DcR3 via 'decoy' and 'non-decoy' functions, and discusses the potential of DcR3 as a biomarker to predict cancer invasion and inflammation progression. We also discuss the possible utility of recombinant DcR3 as a therapeutic agent to control autoimmune diseases, as well as the potential to attenuate tumor progression by inhibiting DcR3 expression.

Decoy receptor 3 protects non-obese diabetic mice from autoimmune diabetes by regulating dendritic cell maturation and function

Decoy receptor 3 (DcR3), a member of the tumor necrosis factor receptor superfamily, regulates immune responses through competing with receptors of Fas ligand (FasL), LIGHT and TNF-like molecule 1A (TL1A). We have previously demonstrated that transgenic expression of DcR3 in a β cell-specific manner significantly protects non-obese diabetic (NOD) mice from autoimmune diabetes. In this study, we further investigated the systemic effect of DcR3 in regulating lymphocytes and dendritic cells in NOD mice. Our results demonstrated that both DcR3 plasmid and protein treatments significantly inhibited insulitis and diabetes. Lymphocytes from DcR3.Fc-treated mice revealed less proliferative potential and transferred ameliorated diabetes. By administration of DcR3.Fc in T1 and T2 double transgenic NOD mice expressing human Thy1 or murine Thy1.1 surface marker under IFN-γ or IL-4 promoter control respectively, we observed a remarkable reduction of Th1 and an increase of Th2 immune responses in vivo. Strikingly, in vitro polarization experiments exhibited that not only Th1 but also Th17 cell differentiation was significantly inhibited in splenocytes treated with DcR3.Fc protein. However, this phenomenon was only observed in splenocytes, not in purified CD4(+) T cells, suggesting that DcR3-mediated inhibition of Th1 and Th17 differentiation is not T cell-autonomous and maybe through other cell types such as dendritic cells. Finally, our results demonstrated that DcR3 directly modulates the differentiation and maturation of dendritic cells and subsequently regulates the differentiation and effector function of T cells.

Neutralizing endogenous chemokines with small molecules. Principles and potential therapeutic applications

Regulation of cellular responses to external stimuli such as hormones, neurotransmitters, or cytokines is achieved through the control of all steps of the complex cascade starting with synthesis, going through maturation steps, release, distribution, degradation and/or uptake of the signalling molecule interacting with the target protein. One possible way of regulation, referred to as scavenging or neutralization of the ligand, has been increasingly studied, especially for small protein ligands. It shows innovative potential in chemical biology approaches as well as in disease treatment. Neutralization of protein ligands, as for example cytokines or chemokines can lead to the validation of signalling pathways under physiological or pathophysiological conditions, and in certain cases, to the development of therapeutic molecules now used in autoimmune diseases, chronic inflammation and cancer treatment. This review explores the field of ligand neutralization and tries to determine to what extent small chemical molecules could substitute for neutralizing antibodies in therapeutic approaches.

Decoy receptor 3 ameliorates experimental autoimmune encephalomyelitis by directly counteracting local inflammation and downregulating Th17 cells

To investigate the therapeutic potential of decoy receptor 3 (DcR3) in multiple sclerosis (MS), we used intrathecal (IT) administration of DcR3 into C57/BL6 mice with experimental autoimmune encephalomyelitis (EAE). DcR3 significantly ameliorated EAE symptoms as shown by a lower clinical score and less inflammation in the spinal cord. The expression of TNF-alpha, IFN-gamma, and IL-17 was lower in the spinal cord in IT DcR3-treated mice. Flow cytometry showed a drastic reduction in IL-17-producing CD4 T cells, slightly fewer IFN-gamma producing CD4 T cells and more IL-4-producing CD4 T cells isolated from the central nervous system (CNS) of IT DcR3-treated mice than of controls. Myelin oligodendrocyte glycoprotein (MOG)-specific T cell proliferation was significantly inhibited in DcR3-treated mice. The IL-17 concentration was lower and the IL-4 concentration higher in the supernatants of MOG-stimulated splenocytes from DcR3-treated mice. An adoptive transfer study showed that splenocytes from DcR3-treated mice retained this disease-inhibiting ability. Our data suggest that DcR3 has potential as a suppressor of CNS inflammation in EAE, which may be attributed to either direct inhibition of CNS inflammation or suppression of encephalitogenic Th17 cells. In conclusion, we demonstrate a therapeutic effect of DcR3 in EAE, suggesting its potential for treating human MS.

Clinical significance of elevated serum DcR3 in patients with hepatocellular carcinoma

AIM: To investigate the diagnostic value and clinical significance of elevated serum decoy receptor 3 (DcR3) in patients with hepatocellular carcinoma (HCC).

METHODS: Serum DcR3 levels were measured using enzyme-linked immunosorbent assay (ELISA) in 67 patients with HCC, 8 patients with liver cirrhosis, 17 patients with cholecystitis and 28 healthy individuals. Serum alpha fetoprotein (AFP) levels were measured by chemiluminescence. The expression of DcR3 in HCC tissue was evaluated by immunohistochemistry (IHC).

RESULTS: The levels of serum DcR3 in both HCC and liver cirrhosis patients were significantly higher than that in healthy individuals (P < 0.01). The level of serum DcR3 in HCC patients was correlated with the development of cirrhosis, capsular infiltration and metastasis (P < 0.05). There was a positive correlation between the levels of DcR3 in the serum and HCC tissue (r = 0.395, P < 0.01). The positive rate of DcR3 in the serum was significantly higher than that in HCC tissue (P < 0.05). The sensitivities of single detection of AFP or DcR3 were 82% and 3 76%, respectively. In contrast, the sensitivity of combined detection of AFP and DcR3 rose to 93%.

CONCLUSION: Elevated serum DcR3 may play an important role in the pathogenesis, development, invasion and metastasis of HCC. It may be of great significance for the screening, diagnosis and prognosis of HCC to simultaneously monitor the levels of DcR3 and AFP in the serum of high-risk populations and HCC patients.