The TL1A/DR3/DcR3 pathway in autoimmune rheumatic diseases

DcR3-associated risk score: correlating better prognosis and enhanced predictive power in colorectal cancer

Decoy receptor 3 (DcR3), a novel soluble protein belonging to the tumor necrosis factor receptor (TNFR) family, has been previously associated with tumorigenesis in various cancers. However, in our study, we unexpectedly found that DcR3 may promote patient survival time in colorectal cancer (CRC). Through an analysis of The Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO) datasets, we discovered that high levels of DcR3 are associated with improved overall survival (OS) and disease-free survival (DFS) in CRC patients. Further investigation revealed that DcR3 is correlated with favorable clinical features in Metastasis 0 (M0) and stage I/II CRC patients, suggesting it may act as a suppressive factor in CRC. Gene Set Enrichment Analysis (GSEA) demonstrated that the high DcR3 group is enriched in the IL-17 signaling pathway and other immune-related pathways, and Single Sample Gene Set Enrichment Analysis (ssGSEA) revealed a higher abundance of Tumor Infiltrating Lymphocytes (TIL) in the DcR3 high group. To better understand the function of DcR3, we constructed a DcR3-associated riskscore (DARS) model using machine learning, comprising three genes (DPP7, KDM3A, and TMEM86B). The DARS model indicated that high riskscore patients have an unfavorable prognosis, and it is associated with advanced stages (III/IV), T3/4 tumors, and N1/2 lymph node involvement. Additionally, high riskscore group exhibited more frequent gene mutations, such as TTN, MUC16, and SYNE1, with SYNE1 mutation being related to poor prognosis. Intriguingly, DcR3 showed higher expression in the low riskscore group. These results suggest that DcR3 could serve as a potential prognostic biomarker in CRC and may play a crucial role in favorably modulating the immune response in this malignancy.

TL1A inhibition for inflammatory bowel disease treatment: From inflammation to fibrosis

The pivotal role of TL1A in modulating immune pathways crucial for inflammatory bowel disease (IBD) and intestinal fibrosis offers a promising therapeutic target. Phase 2 trials (TUSCANY and ARTEMIS-UC) evaluating an anti-TL1A antibody show progress in expanding IBD therapeutic options. First-in-human data reveal reduced expression of genes associated with extracellular matrix remodeling and fibrosis post-anti-TL1A treatment. Investigational drug TEV-48574, potentially exerting dual antifibrotic and anti-inflammatory effects, is undergoing a phase 2 basket study in both ulcerative colitis (UC) and Crohn disease (CD). Results are eagerly awaited, marking advancements in IBD therapeutics. This critical review comprehensively examines the existing literature, illuminating TL1A and the intricate role of DR3 in IBD, emphasizing the evolving therapeutic landscape and ongoing clinical trials, with potential implications for more effective IBD management.

Hypomethylation of Tumor necrosis factor-like cytokine 1A(TL1A) and its decoy receptor 3 expressive level increase has diagnostic value in HBV-associated cirrhosis

For patients with cirrhosis, early diagnosis is the key to delaying the development of liver fibrosis and improving prognosis. This study aimed to investigate the clinical significance of TL1A, which is a susceptibility gene for hepatic fibrosis, and DR3 in the development of cirrhosis and fibrosis. We analyzed the expression of TL1A, DR3, and other inflammatory cytokines associated with liver fibrosis in serum and PBMCs in 200 patients.TL1A methylation level was lower in patients with HBV-associated LC than in the other groups. In addition, the mRNA level and serum of TL1A and DR3 expression levels were found to increase in the LC. Hypomethylation of the TL1A promoter is present in HBV-associated LC, and TL1A and DR3 are highly expressed in HBV-associated cirrhosis. These results indicate that TL1A and DR3 may play an important role in the pathogenesis of LC and TL1A methylation levels may serve as a noninvasive biomarker for early diagnosis and progression of LC.

LIGHT (TNFSF14) Costimulation Enhances Myeloid Cell Activation and Antitumor Immunity in the Setting of PD-1/PD-L1 and TIGIT Checkpoint Blockade

Coinhibition of TIGIT (T cell immunoreceptor with Ig and ITIM domains) and PD-1/PD-L1 (PD-1/L1) may improve response rates compared with monotherapy PD-1/L1 blockade in checkpoint naive non-small cell lung cancer with PD-L1 expression >50%. TIGIT mAbs with an effector-competent Fc can induce myeloid cell activation, and some have demonstrated effector T cell depletion, which carries a clinical liability of unknown significance. TIGIT Ab blockade translates to antitumor activity by enabling PVR signaling through CD226 (DNAM-1), which can be directly inhibited by PD-1. Furthermore, DNAM-1 is downregulated on tumor-infiltrating lymphocytes (TILs) in advanced and checkpoint inhibition-resistant cancers. Therefore, broadening clinical responses from TIGIT blockade into PD-L1low or checkpoint inhibition-resistant tumors, may be induced by immune costimulation that operates independently from PD-1/L1 inhibition. TNFSF14 (LIGHT) was identified through genomic screens, in vitro functional analysis, and immune profiling of TILs as a TNF ligand that could provide broad immune activation. Accordingly, murine and human bifunctional fusion proteins were engineered linking the extracellular domain of TIGIT to the extracellular domain of LIGHT, yielding TIGIT-Fc-LIGHT. TIGIT competitively inhibited binding to all PVR ligands. LIGHT directly activated myeloid cells through interactions with LTβR (lymphotoxin β receptor), without the requirement for a competent Fc domain to engage Fcγ receptors. LIGHT costimulated CD8+ T and NK cells through HVEM (herpes virus entry mediator A). Importantly, HVEM was more widely expressed than DNAM-1 on T memory stem cells and TILs across a range of tumor types. Taken together, the mechanisms of TIGIT-Fc-LIGHT promoted strong antitumor activity in preclinical tumor models of primary and acquired resistance to PD-1 blockade, suggesting that immune costimulation mediated by LIGHT may broaden the clinical utility of TIGIT blockade.

Role of TL1A in Inflammatory Autoimmune Diseases: A Comprehensive Review

TL1A, also called TNFSF15, is a member of tumor necrosis factor family. It is expressed in different immune cell, such as monocyte, macrophage, dendritic cell, T cell and non-immune cell, for example, synovial fibroblast, endothelial cell. TL1A competitively binds to death receptor 3 or decoy receptor 3, providing stimulatory signal for downstream signaling pathways, and then regulates proliferation, activation, apoptosis of and cytokine, chemokine production in effector cells. Recent findings showed that TL1A was abnormally expressed in autoimmune diseases, including rheumatoid arthritis, inflammatory bowel disease, psoriasis, primary biliary cirrhosis, systemic lupus erythematosus and ankylosing spondylitis. In vivo and in vitro studies further demonstrated that TL1A was involved in development and pathogenesis of these diseases. In this study, we comprehensively discussed the complex immunological function of TL1A and focused on recent findings of the pleiotropic activity conducted by TL1A in inflammatory autoimmune disease. Finish of the study will provide new ideas for developing therapeutic strategies for these diseases by targeting TL1A.

Decoy receptor 3 is involved in epidermal keratinocyte commitment to terminal differentiation via EGFR and PKC activation

Decoy receptor 3 (DcR3) is a soluble receptor for Fas ligand, LIGHT and TL1A, but it also exerts effector functions. Previously, we found that DcR3 is upregulated in the serum and lesional skin of patients with psoriasis and is upregulated by EGFR activation in proliferating primary human epidermal keratinocytes. However, the functional role of intracellular DcR3 in keratinocyte differentiation is still incompletely defined. Herein, primary cultured human epidermal keratinocytes were differentiated by phorbol 12-myristate 13-acetate (PMA) treatment, calcium treatment and cell confluence, which are three standard in vitro differentiation models. We found that the constitutive expression of the DcR3 gene and protein was progressively suppressed during terminal differentiation of keratinocytes. These changes were correlated with downregulation of EGFR activation during keratinocyte differentiation. EGFR inhibition by gefitinib further decreased confluence-induced suppression of DcR3 mRNA expression, and, vice versa, knocking down DcR3 expression attenuated EGFR and EGFR ligand expression as well as EGFR activation. Under conditions without a change in cell growth, DcR3 silencing reduced the expression of involucrin and transglutaminase 1 but enhanced the induction of the terminal differentiation markers keratin 10 and loricrin. Of note, DcR3 interacted with PKCα and PKCδ and enhanced PKC activity. In keratinocytes with PKCα and PKCδ silencing, differentiation markers were differentially affected. In conclusion, DcR3 expression in keratinocytes is regulated by EGFR and forms a positive feedback loop to orchestrate constitutive EGFR and PKC activity. During differentiation, DcR3 is downregulated and involved in modulating the pattern of terminal differentiation.

A protein linked to cancer and various inflammatory diseases may also be an important driver for the skin condition in psoriasis. The outer surface of the skin is formed by cells called keratinocytes, which transition from a highly proliferative state to a fully mature state where they no longer divide. This developmental process is disrupted in psoriasis. Researchers led by Wan-Wan Lin at National Taiwan University, Taipei, have now identified a prominent role for a protein called decoy receptor 3 (DcR3), which is a biomarker for a variety of disorders and is also abnormally expressed in keratinocytes in psoriatic lesions. Lin and colleagues demonstrated that DcR3 interacts with multiple cellular signaling pathways that coordinate cell differentiation. These findings reveal how aberrant DcR3 activity might lead to the abnormal keratinocyte developmental behavior observed in psoriasis.

Immunological Regulation of Intestinal Fibrosis in Inflammatory Bowel Disease

Intestinal fibrosis is a late-stage phenotype of inflammatory bowel disease (IBD), which underlies most of the long-term complications and surgical interventions in patients, particularly those with Crohn's disease. Despite these issues, antifibrotic therapies are still scarce, mainly due to the current lack of understanding concerning the pathogenetic mechanisms that mediate fibrogenesis in patients with chronic intestinal inflammation. In the current review, we summarize recent evidence regarding the cellular and molecular factors of innate and adaptive immunity that are considered critical for the initiation and amplification of extracellular matrix deposition and stricture formation. We focus on the role of cytokines by dissecting the pro- vs antifibrotic components of the immune response, while taking into consideration their temporal association to the progressive stages of the natural history of IBD. We critically present evidence from animal models of intestinal fibrosis and analyze inflammation-fibrosis interactions that occur under such experimental scenarios. In addition, we comment on recent findings from large-scale, single-cell profiling of fibrosis-relevant populations in IBD patients. Based on such evidence, we propose future potential targets for antifibrotic therapies to treat patients with IBD.

MicroRNAs in pemphigus and pemphigoid diseases

Autoimmune blistering diseases are a heterogenous group of dermatological disorders characterized by blisters and erosions of the skin and/or mucous membranes induced by autoantibodies against structural proteins of the desmosome or the dermal-epidermal adhesion complex including the hemidesmosome. They consist of the two major disease groups, pemphigus and pemphigoid diseases (PPDs). The diagnosis is based on clinical findings, histopathology, direct immunofluorescence, and detection of circulating autoantibodies. The pathogenesis is not fully elucidated, prognostic factors are lacking, and to date, there is no cure for PPDs. MicroRNAs (miRNAs) represent small, non-coding RNAs that play a pivotal role in the posttranscriptional regulation of gene expression. Their dysfunction was highlighted to play a significant role in the pathogenesis of various diseases. Even though a link between miRNAs and autoimmune blistering diseases had been suggested, the research of their involvement in the pathogenesis of PPDs is still in its infancy. miRNAs hold promise for uncovering new layers in the pathogenesis of PPDs, in order to improve diagnosis and also to develop potential therapeutic options. In the current article, we provide an overview regarding current knowledge of miRNAs in terms of complex pathogenesis of PPDs, and, also, their potential role as biomarkers, predictive factors and therapeutic targets.

TL1A-DR3 Plasma Levels Are Predictive of HIV-1 Disease Control, and DR3 Costimulation Boosts HIV-1-Specific T Cell Responses

Relative control of HIV-1 infection has been linked to genetic and immune host factors. In this study, we analyzed 96 plasma proteome arrays from chronic untreated HIV-1-infected individuals using the classificatory random forest approach to discriminate between uncontrolled disease (plasma viral load [pVL] >50,000 RNA copies/ml; CD4 counts 283 cells/mm3, n = 47) and relatively controlled disease (pVL <10,000 RNA copies/ml; CD4 counts 657 cells/mm3, n = 49). Our analysis highlighted the TNF molecule's relevance, in particular, TL1A (TNFSF15) and its cognate DR3 (TNFSRF25), both of which increased in the relative virus control phenotype. DR3 levels (in plasma and PBMCs) were validated in unrelated cohorts (including long-term nonprogressors), thus confirming their independence from CD4 counts and pVL. Further analysis in combined antiretroviral treatment (cART)-treated individuals with a wide range of CD4 counts (137-1835 cells/mm3) indicated that neither TL1A nor DR3 levels reflected recovery of CD4 counts with cART. Interestingly, in cART-treated individuals, plasma TL1A levels correlated with regulatory T cell frequencies, whereas soluble DR3 was strongly associated with the abundance of effector HLA-DR+CD8+ T cells. A positive correlation was also observed between plasma DR3 levels and the HIV-1-specific T cell responses. In vitro, costimulation of PBMC with DR3-specific mAb increased the magnitude of HIV-1-specific responses. Finally, in splenocytes of DNA.HTI-vaccinated mice, costimulation of HTI peptides and a DR3 agonist (4C12) intensified the magnitude of T cell responses by 27%. These data describe the role of the TL1A-DR3 axis in the natural control of HIV-1 infection and point to the use of DR3 agonists in HIV-1 vaccine regimens.

Polymorphism rs6478109 in the TNFSF15 gene contributes to the susceptibility to Crohn's disease but not ulcerative colitis: a meta-analysis

Objective

Polymorphisms in the tumor necrosis factor superfamily 15 (TNFSF15) gene contribute to susceptibility to inflammatory bowel disease (IBD). However, associations between TNFSF15 rs6478109, rs7869487, and rs7865494 polymorphisms and IBD remain unclear.

Methods

Eligible articles were retrieved from the PubMed, EMBASE, Web of Science, and CNKI databases through 20 March 2020. Pooled odds ratios (ORs) with 95% confidence intervals (CIs) were calculated to evaluate the relationships of TNFSF15 polymorphisms with IBD susceptibility.

Results

Under the recessive model, TNFSF15 rs6478109 was associated with IBD risk (OR = 0.56; 95% CI: 0.35, 0.92). Stratification analyses based on the type of disease—Crohn’s disease (CD) or ulcerative colitis (UC)—revealed a significant association under the allelic and recessive models between TNFSF15 rs6478109 and CD (allelic model: OR = 0.84, 95% CI: 0.71, 0.99; recessive model: OR = 0.44, 95% CI: 0.22, 0.87) but not UC. Stratification by ethnicity indicated a significantly decreased risk of IBD in Asian populations with TNFSF15 rs6478109 under the recessive model (OR = 0.56, 95% CI: 0.35, 0.92).

Conclusions

Our meta-analysis suggested that under the allelic and recessive models, the TNFSF15 rs6478109 polymorphism was likely protective for CD but not UC in the Asian population.

Circulating TNF-like protein 1A (TL1A) is elevated early in rheumatoid arthritis and depends on TNF

Background

The tumor necrosis factor (TNF) superfamily cytokine TNF-like protein 1A (TL1A) and its receptor DR3 are essential for diverse animal models of autoimmune disease and may be pathogenic in rheumatoid arthritis (RA). However, the relationship of TL1A to disease duration, activity, and response to anti-TNF and other therapies in RA is not clear.

Methods

We measured soluble TL1A in synovial fluid (SF), serum, or plasma from RA first-degree relatives (FDRs) and in early RA and established disease. We measured the effects of anti-TNF and methotrexate (MTX) therapy on circulating TL1A from multiple independent RA treatment trials. We also determined the ability of a blocking anti-TL1A antibody to inhibit clinical disease and articular bone destruction in the murine collagen-induced arthritis (CIA) model of human RA.

Results

Soluble TL1A was specifically elevated in the blood and SF of patients with RA compared to patients with other diseases and was elevated early in disease and in at-risk anti-cyclic citrullinated peptide (CCP) (+) first-degree relatives (FDRs). Therapeutic TNF inhibition reduced serum TL1A in both responders and non-responders, whereas TL1A declined following MTX treatment only in responders. In murine CIA, TL1A blockade was clinically efficacious and reduced bone erosions.

Conclusions

TL1A is specifically elevated in RA from early in the disease course and in at-risk FDRs. The decline in TL1A after TNF blockade suggests that TL1A levels may be a useful biomarker for TNF activity in RA. These results support the further investigation of the relationship between TL1A and TNF and TL1A blockade as a potential therapeutic strategy in RA.

TL1A/TNFR2-mediated mitochondrial dysfunction of fibroblast-like synoviocytes increases inflammatory response in patients with rheumatoid arthritis via reactive oxygen species generation

Rheumatoid arthritis (RA) is the major autoimmune destructive disease of joints with a complicated pathogenesis. The contribution of tumor necrosis factor-like ligand 1A (TL1A) in RA pathogenesis, especially on fibroblast-like synoviocytes (FLS), has been suggested clinically. The present study investigated the role of TL1A in mitochondrial dysfunction, induced oxidative stress in mitochondria, apoptosis resistance and the inflammatory response in FLS obtained from RA patients (RA-FLS). RA-FLS were incubated with TL1A and tumor necrosis factor receptor 2 (TNFR2) antagonist. Respiratory function, mitochondrial membrane potential and respiration associated genes of mitochondria were measured in both TL1A stimulated and non-stimulated RA-FLS. Additionally, the effects of TL1A on reactive oxygen species (ROS) production in mitochondria, apoptosis and the inflammatory response in RA-FLS were also assessed. The role of TL1A in association between ROS generation, especially mitochondrial type and the inflammatory response, was evaluated by measuring inflammation-related cytokines and signaling pathways using ROS inhibitors, diphenyleneiodonium chloride and Mito-TEMPO (Sigma-Aldrich, Miamisburg, OH, USA). We found that TL1A induced mitochondrial dysfunction by weakening mitochondrial respiration and membrane potential, which was blocked by a TNFR2 antagonist. Increased ROS synthesis in impaired mitochondria was observed with MitoSOX (Invitrogen, CA, USA) immunofluorescence staining in TL1A-stimulated RA-FLS but inhibited by a TNFR2 antagonist. TL1A influenced apoptosis resistance and inflammatory mediators via TNFR2. Inhibition of mitochondria-derived ROS compromised the production of inflammatory factors in TL1A-stimulated RA-FLS, suggesting that mitochondrial dysfunction mediated by the TL1A/TNFR2 axis might amplify the inflammatory response via regulation of mitochondria-derived ROS generation. Collectively, our results reveal that TL1A might be involved in making FLS more aggressive in RA pathogenesis via cell respiration interruption.

Gene expression profiles of TNF-like cytokine 1A (TL1A) and its receptors death receptor 3 (DR3) and decoy receptor 3 (DcR3) in multiple sclerosis

TL1A/DR3/DcR3 pathway is an important mediator of inflammatory responses and contributes to the pathogenesis of several chronic inflammatory diseases. Therefore, we analysed PBMC gene expression of these molecules in 30 relapsing-remitting multiple sclerosis (RRMS) patients, 8 secondary progressive MS (SPMS), 9 primary progressive MS (PPMS), 11 clinically isolated syndrome (CIS) patients, and 16 healthy controls (HCs), to evaluate their biomarker potential in MS. The results showed significant decrease in TL1A expression in RRMS compared to other study groups. TL1A as a marker of inflammation, we found its higher expression among treatment näive RRMS patients as compared to HCs and among patients who were treated with DMTs. Moreover, TL1A expression was found to be associated with the clinical and MRI findings of MS patients suggesting its possible involvement in the establishment or preservation of immune system homeostasis or in the regulation of inflammatory activity. Taken together, these findings suggest the TL1A should be evaluated further for its potential as a candidate biomarker of inflammatory activity and the marker of therapeutic response to immunomodulatory treatments in MS.

TNFSF/TNFRSF cytokine gene expression in sickle cell anemia: Up-regulated TNF-like cytokine 1A (TL1A) and its decoy receptor (DcR3) in peripheral blood mononuclear cells and plasma

BACKGROUND

Sickle cell anemia (SCA), a disorder with an important inflammatory component, where vasoocclusion is major contributor to the disease pathophysiology. Pro-inflammatory cytokines play an important regulatory role in the process of inflammation. We investigated the expression TL1A/DR3/DcR3 cytokine signaling pathway in peripheral blood mononuclear cells (PBMC) and their corresponding plasma levels in SCA subjects who presented with acute painful episodes.

MATERIALS AND METHODS

PBMC were isolated from the blood of SCA subjects and normal healthy controls. RNA isolated from PBMC was used for real time gene expression of TL1A/DR3/DcR3. Gene expression was compared in subgroups within SCA subjects with co-inherited fetal hemoglobin (HbF) or alpha-globin gene deletions. Plasma prepared from blood was used for determination of TL1A/DR3/DcR3 proteins by ELISA assays.

RESULTS

In the PBMC of SCA subjects, expression of TL1A and DcR3 is elevated, while DR3 expression is lowered in comparison to normal control PBMC. In SCA subjects with HbF > 10%, TL1A/DcR3 expression is lower, while HbF < 10% is associated with increased TL1A/DcR3 expression. Moreover, subjects with HbF > 10% appear to have significantly fewer pain episodes in comparison to those with HbF < 10%. Deletion of alpha-globin genes appears to have no significant effect on TL1A/DR3/DcR3 expression. Circulating levels of TL1A, DR3 and DcR3 in plasma were significantly elevated in SCA subjects.

CONCLUSIONS

Elevated TL1A and DcR3 expression in PBMC of SCA subjects during painful vasoocclusive crisis, suggest an altered TL1A expression may contribute to the pathophysiology of vasoocclusive crisis in SCA. HbF > 10% appears to moderate TL1A elevation, while HbF < 10% exacerbates TL1A/DcR3 responses. Furthermore, subjects with HbF > 10% have significantly lower pain episodes reported as compared to subjects with HbF < 10%.

Hepatitis B X protein upregulates decoy receptor 3 expression via the PI3K/NF-κB pathway

Chronic hepatitis B (CHB) is associated with the development of hepatocellular carcinoma (HCC). Decoy receptor 3 (DcR3) is a tumor necrosis factor receptor that promotes tumor cell survival by inhibiting apoptosis and interfering with immune surveillance. Previous studies showed that DcR3 was overexpressed in HCC cells and that short hairpin RNA (shDcR3) sensitizes TRAIL-resistant HCC cells. However, the expression of DcR3 during hepatitis B virus (HBV) infection has not been investigated. Here, we demonstrated that DcR3 was overexpressed in CHB patients and that DcR3 upregulation was positively correlated with the HBV DNA load and liver injury (determined by histological activity index, serum alanine aminotransferase level, and aspartate aminotransferase level). We found that hepatitis B virus X protein (HBx) upregulated DcR3 expression in a dose-dependent manner, but this increase was blocked by NF-κB inhibitors. HBx also induced the activation of NF-κB, and the NF-κB subunits p65 and p50 upregulated DcR3 by directly binding to the DcR3 promoters. Inhibition of PI3K significantly downregulated DcR3 and inhibited the binding of NF-κB to the DcR3 promoters. Our results demonstrate that the HBx induced DcR3 expression via the PI3K/NF-κB pathway; this process may contribute to the development of HBV-mediated HCC.

Expression and Clinical Significance of Decoy Receptor 3 in Acute-on-Chronic Liver Failure

AIMS

To explore the expression level and clinical significance of decoy receptor 3 (DcR3) in patients with acute-on-chronic liver failure (ACLF).

METHODS

Serum DcR3 levels were measured by enzyme-linked immunosorbent assay (ELISA) in 76 patients with ACLF and 41 non-ACLF patients with chronic liver disease. Blood routine and liver functions were accessed for their correlations with DcR3.

RESULTS

Serum DcR3 in ACLF patients was significantly higher than that in non-ACLF patients. It was positively correlated with neutrophilic granulocyte, aspartate aminotransferase, prothrombin time, and international standardized ratio, but negatively correlated with platelet and serum albumin. At the early stage, the level of DcR3 was not significantly different between the survival and nonsurvival group of ACLF. However, at the late stage, DcR3 increased in nonsurvival and gradually decreased in survivals. The baseline DcR3 could not sufficiently predict the outcome of ACLF, while the change of DcR3 within the first week displayed a better predictive value than model for end-stage liver disease (MELD) score.

CONCLUSIONS

DcR3 was highly expressed in patients with ACLF and correlated with several clinical indices. Dynamic change of DcR3 might predict the prognosis of ACLF.

Role of TNFSF15 in the intestinal inflammatory response

Gastrointestinal diseases, specifically Crohn’s disease, ulcerative colitis, diverticular disease, and primary biliary cirrhosis are all characterized by complicated inflammation of the digestive tract. Their pathology is multifactorial, and risk factors encompass both genetic and environmental factors. Recent advances in the genetic component of inflammatory bowel diseases (IBDs) have revealed that the tumor necrosis factor superfamily member 15 (TNFSF15) contains a number of risk alleles associated not only with IBD but also with other diseases such as diverticular disease and primary biliary cirrhosis. These risk alleles in TNFSF15 and the altered expression of its gene product can serve as the common ground between these disorders by explaining at least some of the underlying processes that lead to a dysregulated immune response and subsequent chronic inflammation. Here, we aim to outline how the TNFSF15 gene is involved in the proliferation and cell fate of different populations of T cells and subsequently in the control of both pro- and anti-inflammatory cytokines. Furthermore, we summarize what is currently known of TNFSF15 control region variants, how they are associated with each mentioned disease, and how these variants can explain the autoimmune pathology of said diseases through altered TNFSF15 expression.

Expression of death receptor 3 (DR3) on peripheral blood mononuclear cells of patients with psoriasis vulgaris

BACKGROUND

A series of previous reports indicated that tumour necrosis factor-like ligand 1A (TL1A) and its receptor death receptor 3 (DR3) are involved in the pathogenesis of psoriasis vulgaris (PV), which is a common chronic skin disease accompanied by a number of comorbidities, although their exact roles remain unclear. Our previous studies demonstrated that serum TL1A levels were substantially elevated in patients with PV, but the detection of DR3 expression in peripheral blood mononuclear cells (PBMCs) of patients with PV had not been reported. Therefore, we detected DR3 expression on CD4+, CD8+, CD14+ and CD19+ PBMCs of patients with PV, atopic dermatitis (AD) and healthy volunteers.

METHODS

Blood samples were collected from participants with PV before and after treatment. Then, PBMCs from patients with PV were isolated. The Psoriasis Area Severity Index (PASI) was used to assess severity in patients with PV. The DR3 on CD4+, CD8+, CD14+ and CD19+ PBMCs were detected by flow cytometry analysis. Pearson's correlation analysis was then used to investigate the relationship between DR3 expression and PASI scores in patients with PV.

RESULTS

Comparing with the healthy volunteers and patients with AD, the percentage of DR3-expressing on CD8+ and CD14+ PBMCs in patients with PV was elevated, but the percentage of DR3-expressing on CD8+ and CD14+ cells decreased after anti-inflammatory treatment, which was correlated with PASI scores.

CONCLUSIONS

Taken together, these findings suggest that DR3 may play a key role in the pathogenesis of PV.

Clinical significance of decoy receptor 3 upregulation in patients with hepatitis B and liver fibrosis

Decoy receptor 3 (DcR3) is a tumor necrosis factor receptor, which may inhibit apoptosis. The aim of the present study was to investigate the clinical significance of DcR3 upregulation in patients with chronic hepatitis B (CHB) and hepatic fibrosis. A total of 128 patients with a clinical diagnosis of CHB who underwent liver biopsy were included in the present study. The expression levels of DcR3, hyaluronic acid (HA), type III procollagen, type IV collagen (IV-C) and laminin protein were assessed. The diagnostic value of DcR3 in patients with CHB with hepatic fibrosis was determined using receiver operating characteristic (ROC) curve analysis. DcR3 was significantly upregulated in patients with CHB, particularly in patients with active CHB. The expression of DcR3 was significantly increased in patients with CHB with liver fibrosis and liver cirrhosis, compared with patients with CHB without liver fibrosis. The area under the ROC curve for the diagnosis of CHB liver fibrosis based on DcR3 or DcR3 combined with IV-C/HA was 0.807 or 0.869, with a sensitivity and specificity of 76.9 and 77.8% or 84.6 and 81.2%, respectively. DcR3 is a marker for liver fibrosis in patients with hepatitis B infection. The use of DcR3 in combination with IV-C and HA may further increase its diagnostic value for liver fibrosis.

Death Receptor 3 Signaling Controls the Balance between Regulatory and Effector Lymphocytes in SAMP1/YitFc Mice with Crohn's Disease-Like Ileitis

Death receptor 3 (DR3), a member of the tumor necrosis factor receptor (TNFR) superfamily, has been implicated in regulating T-helper type-1 (TH1), type-2 (TH2), and type-17 (TH17) responses as well as regulatory T cell (Treg) and innate lymphoid cell (ILC) functions during immune-mediated diseases. However, the role of DR3 in controlling lymphocyte functions in inflammatory bowel disease (IBD) is not fully understood. Recent studies have shown that activation of DR3 signaling modulates Treg expansion suggesting that stimulation of DR3 represents a potential therapeutic target in human inflammatory diseases, including Crohn's disease (CD). In this study, we tested a specific DR3 agonistic antibody (4C12) in SAMP1/YitFc (SAMP) mice with CD-like ileitis. Interestingly, treatment with 4C12 prior to disease manifestation markedly worsened the severity of ileitis in SAMP mice despite an increase in FoxP3+ lymphocytes in mesenteric lymph node (MLN) and small-intestinal lamina propria (LP) cells. Disease exacerbation was dominated by overproduction of both TH1 and TH2 cytokines and associated with expansion of dysfunctional CD25-FoxP3+ and ILC group 1 (ILC1) cells. These effects were accompanied by a reduction in CD25+FoxP3+ and ILC group 3 (ILC3) cells. By comparison, genetic deletion of DR3 effectively reversed the inflammatory phenotype in SAMP mice by promoting the expansion of CD25+FoxP3+ over CD25-FoxP3+ cells and the production of IL-10 protein. Collectively, our data demonstrate that DR3 signaling modulates a multicellular network, encompassing Tregs, T effectors, and ILCs, governing disease development and progression in SAMP mice with CD-like ileitis. Manipulating DR3 signaling toward the restoration of the balance between protective and inflammatory lymphocytes may represent a novel and targeted therapeutic modality for patients with CD.

Cleavage of TL1A Differentially Regulates Its Effects on Innate and Adaptive Immune Cells

TNF superfamily cytokines play major roles in the regulation of adaptive and innate immunity. The TNF superfamily cytokine TL1A (TNFSF15), through its cognate receptor DR3 (TNFRSF25), promotes T cell immunity to pathogens and directly costimulates group 2 and 3 innate lymphoid cells. Polymorphisms in the TNFSF15 gene are associated with the risk for various human diseases, including inflammatory bowel disease. Like other cytokines in the TNF superfamily, TL1A is synthesized as a type II transmembrane protein and cleaved from the plasma membrane by metalloproteinases. Membrane cleavage has been shown to alter or abrogate certain activities of other TNF family cytokines; however, the functional capabilities of membrane-bound and soluble forms TL1A are not known. Constitutive expression of TL1A in transgenic mice results in expansion of activated T cells and promotes intestinal hyperplasia and inflammation through stimulation of group 2 innate lymphoid cells. Through the generation of membrane-restricted TL1A-transgenic mice, we demonstrate that membrane TL1A promotes expression of inflammatory cytokines in the lung, dependent upon DR3 expression on T cells. Soluble TL1A alone was unable to produce this phenotype but was still able to induce intestinal type 2 inflammation independently of T cells. These data suggest differential roles for membrane and soluble TL1A on adaptive and innate immune cells and have implications for the consequences of blocking these two forms of TL1A.

A variant of death-receptor 3 associated with rheumatoid arthritis interferes with apoptosis-induction of T cell

Rheumatoid arthritis (RA) is a chronic polyarthritis of unknown etiology. To unravel the molecular mechanisms in RA, we performed targeted DNA sequencing analysis of patients with RA. This analysis identified a variant of the death receptor 3 (DR3) gene, a member of the family of apoptosis-inducing Fas genes, which contains four single-nucleotide polymorphisms (SNPs) and a 14-nucleotide deletion within exon 5 and intron 5. We found that the deletion causes the binding of splicing regulatory proteins to DR3 pre-mRNA intron 5, resulting in a portion of intron 5 becoming part of the coding sequence, thereby generating a premature stop codon. We also found that this truncated DR3 protein product lacks the death domain and forms a heterotrimer complex with wildtype DR3 that dominant-negatively inhibits ligand-induced apoptosis in lymphocytes. Myelocytes from transgenic mice expressing the human DR3 variant produced soluble truncated DR3, forming a complex with TNF-like ligand 1A (TL1A), which inhibited apoptosis induction. In summary, our results reveal that a DR3 splice variant that interferes with ligand-induced T cell responses and apoptosis may contribute to RA pathogenesis.

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.

DcR3 promotes hepatoma cell migration by downregulating E-cadherin expression

Decoy receptor 3 (DcR3), a decoy molecule belonging to the tumor necrosis factor receptor superfamily (TNFRSF), is a soluble receptor that can neutralize the biological effects of three other TNFSF members, namely, Fas ligand (FasL/TNFSF6/CD95L), LIGHT (TNFSF14) and TNF-like molecule 1A (TL1A/TNFSF15). DcR3 expression is increased in tumor cells. As such, DcR3 has been considered a potential biomarker to predict cancer invasion and progression of inflammation. However, the molecular mechanisms of DcR3 in tumor progression and metastasis remain poorly described. In the present study, DcR3 induced cytoskeleton remodeling, inhibited E-cadherin expression, and promoted cancer cell migration. Immunofluorescence and flow cytometry demonstrated that DcR3 expression was increased in hepatoma cells, whereas E-cadherin expression was significantly downregulated. Immunohistochemistry revealed that DcR3 and E-cadherin exhibited an opposite expression pattern between normal and cancerous liver tissues. Moreover, DcR3 treatment promoted IκBα degradation and p65 nuclear translocation. Therefore, the present study uncovered the mechanism underlying the function of DcR3 in cancer cell migration and provides evidence that DcR3 may be a potential target for cancer therapy.

Effect of silencing decoy receptor 3 on biological features of hepatoma cells

AIM

To detect the expression of decoy receptor 3 (DcR3) in hepatoma cells, and to investigate its role in the biological features of hepatoma cells.

METHODS

Real-time PCR and Western blot were used to detect the expression of DcR3 mRNA and protein in human hepatoma cell lines HepG2 and Huh7 and normal hepatocytes (HL-7702 and Chang liver). ELISA was used to detect the level of DcR3 protein in the supernatant of these four cell lines. A lentiviral vector carrying shRNA against DcR3 (LV-shDcR3) was synthesized and used to infect HepG2 and Huh7 cells, with the empty lentiviral vector as a control. After infection, the interference effects were determined by Western blot, cell proliferation was assessed by CCK-8 assay and colony forming assay, cell apoptosis was examined by flow cytometry, and the expression of apoptosis related protein like PARP was detected by Western blot. The expression of TRAIL, FasL and LIGHT before and after infection was also detected by Western blot.

RESULTS

The expression of DcR3 was significantly increased in hepatoma cell lines HepG2 and Huh7 both at the mRNA and protein levels compared with normal hepatocytes. The levels of DcR3 in the supernatants of HepG2 and Huh7 cells were also increased. Compared with the mock group and empty lentiviral vector infected group, the LV-shDcR3 infected group showed reduced expression of DcR3, lower cell viability rate, and higher cell apoptosis rate. The expression of TRAIL and FasL was increased after infection with LV-shDcR3 in HepG2 and Huh7 cells.

CONCLUSION

The expression of DcR3 is elevated in hepatoma cells. Down-regulation of the expression of DcR3 inhibits cell proliferation and induces cell apoptosis in hepatoma cells, via mechanisms that may be related with the TRAIL and FasL apoptosis pathway.

DcR3 gene polymorphisms are associated with sporadic breast infiltrating ductal carcinoma in Northeast Chinese women

Decoy Receptor 3 (DcR3), also called TNFRSF6β, is a member of the tumor necrosis factor receptor superfamily and is a soluble receptor for FasL. DcR3 is overexpressed in cancers and contributes to tumorigenesis through immune suppression and promotion of angiogenesis. We found that DcR3 is overexpressed in breast infiltrating ductal carcinoma (IDC) cells as compared with normal controls. We also conducted a case-control study analyzing associations of DcR3 polymorphisms with breast IDC risk. Subjects included 531 females with breast IDC and 592 age-matched healthy controls. Four DcR3 single nucleotide polymorphism loci with minor frequencies of more than 5% (rs3208008, rs41309931, rs2297441 and rs1291207) were genotyped using polymerase chain reaction restriction fragment length polymorphism and sequencing. Our results revealed significant differences in rs41309931genotypes and alleles (P < 0.01). Based on Haploview software analysis, the haplotype block A_rs3208008 G_rs41309931 G_rs2297441 A_rs1291207 exhibited the highest frequency, but, haplotype blocks A_rs3208008 T_rs41309931 G_rs2297441 A_rs1291207 and C_rs3208008 G_rs41309931 G_rs2297441 A_rs1291207 were associated with breast IDC risk. This study also detected associations between DcR3 gene polymorphisms and the clinicopathological features of breast IDC, including lymph node metastasis and C-erbB2, P53, estrogen receptor and progesterone receptor status. These data indicate that DcR3 gene polymorphisms are associated with sporadic breast IDC risk in Northeast Chinese females.

Progranulin: A key player in autoimmune diseases

Autoimmune disease encompasses an array of conditions with a variety of presentations and the involvement of multiple organs. Though the etiologies of many autoimmune conditions are unclear, uncontrolled inflammatory immune response is believed to be a major cause of disease development and progression. Progranulin (PGRN), an anti-inflammatory molecule with therapeutic effect in inflammatory arthritis, was identified as an endogenous antagonist of TNFα by competitively binding to TNFR. PGRN exerts its anti-inflammatory activity through multiple pathways, including induction of T_reg differentiation and IL-10 expression and inhibition of chemokine release from macrophages. In addition, the protective role of PGRN has also been demonstrated in osteoarthritis, inflammatory bowel disease, and psoriasis. Intriguingly, PGRN was reported to contribute to development of insulin resistance in high-fat diet induced diabetes. Emerging evidences indicate that PGRN may also be associated with various autoimmune diseases, including systemic lupus erythematous, systemic sclerosis, multiple sclerosis and Sjogren's syndrome. This review summarizes recent studies of PGRN as a novel target molecule in the field of autoimmune disease, and provides updated information to inspire future studies.

TL1A increased IL-6 production on fibroblast-like synoviocytes by preferentially activating TNF receptor 2 in rheumatoid arthritis

TNF-like protein 1A (TL1A), a member of tumor necrosis factor family, recognized as a ligand of death receptor 3 (DR3) and decoy receptor 3 (DcR3). The interaction of TL1A and DR3 may participate in the pathogenesis of some autoimmune diseases including rheumatoid arthritis (RA). Our previous results showed that high concentrations of TL1A could be found in synovial and serum in RA patients, and it was correlated with disease severity. In addition, TL1A could promote Th17 differentiation induced by TGF-β and IL-6 and increased the production of IL-17A. In the present study, we found that TL1A could promote the expression of IL-6 on fibroblast-like synoviocytes (FLS) of RA patients via NF-κB and JNK signaling pathway. TL1A-stimulated FLS increased the percentage of Th17 of peripheral blood mononuclear cells (PBMC) in RA via the production of IL-6, a critical cytokine involved in the differentiation of Th17. Moreover, the blocking of tumor necrosis factor receptor 2 (TNFR2) decreased TL1A-stimulated IL-6 production by RA FLS. Our results suggest that TL1A was capable of acting on RA FLS to elevate IL-6 expression, which promoted the production of Th17. More importantly, we showed that TL1A could influence RA FLS through binding to TNFR2 rather than DR3 on FLS, which indicated that the treatment of TNF inhibitors not only blocked the TNF but also suppressed the TL1A in RA patients.