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

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.

Decoys as potential therapeutic tools for diabetes

Current therapeutic approaches for diabetes are focused on improving glycemic control to prevent diabetes-related complications, but such approached are not completely successful. Decoy technologies such as decoy oligodeoxynucleotides (ODNs) and decoy peptides have emerged as therapeutic tools in diabetes. Decoy ODNs carry a DNA recognition motif for the binding of transcription factors in order to trap them and block their effects, whereas decoy peptides mimic the binding structure of the receptor protein, bind to the docking site of the target ligand, and prevent the interaction of the ligand and receptor. This review summarizes the technologies that have been developed to date and the studies that have investigated the therapeutic effects of decoy ODNs and peptides in diabetes.

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.

Mechanisms of the prevention and inhibition of the progression and development of non-alcoholic steatohepatitis by genetic and pharmacological decoy receptor 3 supplementation

AIMS

Treatment of non-alcoholic steatohepatitis (NASH) is difficult due to the absence of a proven treatment and its comprehensive mechanisms. In the NASH animal model, upregulated hepatic inflammation and oxidative stress, with the resultant M1 polarization of macrophages as well as imbalanced adipocytokines, all accelerate NASH progression. As a member of the tumor necrosis factor receptor superfamily, decoy receptor 3 (DcR3) not only neutralizes the death ligands, but also performs immune modulations. In this study, we aimed to investigate the possible non-decoy effects of DcR3 on diet-induced NASH mice.

METHODS

Methionine- and choline-deficient (MCD) diet feeding for 9 weeks was applied to induce NASH in BALB/c mice. Decoy receptor 3 heterozygous transgenesis or pharmacological pretreatment with DcR3a for 1 month were designed as interventions. Intrahepatic inflammatory status as well as macrophage polarization, oxidative stress, and steatosis as well as lipogenic gene expression and fibrotic status were analyzed. Additionally, acute effects of DcR3a on HepG2 cells, Hep3B cells, and primary mouse hepatocytes in various MCD medium-stimulated changes were also evaluated.

RESULTS

Both DcR3 genetic and pharmacologic supplement significantly reduced MCD diet-induced hepatic M1 polarization. In addition, DcR3 supplement attenuated MCD diet-increased hepatic inflammation, oxidative stress, adipocytokine imbalance, steatosis, and fibrogenesis. Moreover, acute DcR3a incubation in HepG2 cells, Hep3B cells, and mouse hepatocytes could normalize the expression of genes related to lipid oxidation along with inflammation and oxidative stress.

CONCLUSION

The ability of DcR3 to attenuate hepatic steatosis and inflammation through its non-decoy effects of immune modulation and oxidative stress attenuation makes it a potential treatment for NASH.

Expression of death receptor 3 on peripheral blood mononuclear cells differes in adult IBD patients and children with newly diagnosed IBD

BACKGROUND

Interaction between TL1A and death receptor 3 (DR3) is associated with the pathogenesis of inflammatory bowel disease (IBD), although their role in the development of this disease remains not fully explained. Some studies showed elevated expression of TL1A and DR3 in inflamed intestinal tissue but currently there are no reports concerning expression of DR3 on peripheral blood mononuclear cells (PBMCs) of IBD patients which was the subject of our study.

METHODS

We performed flow cytometry analysis of DR3 expression on CD4(+), CD8(+), CD11c(+), CD14(+) or CD20(+) PBMCs of adults and children with IBD and healthy volunteers with respect to C-reactive protein (CRP) levels in blood. Blood samples were collected from pediatric patients before the beginning of therapy, whereas adults patients were undergoing anti-inflammatory IBD treatment and had much lower CRP levels.

RESULTS

With regard to appropriate healthy volunteers, children with IBD had elevated percentage of DR3-expressing CD4(+), CD8(+), CD11c(+) and CD20(+) PBMCs which, with the exception of DR3(+) CD11c(+) cells in children with ulcerative colitis, was correlated with CRP level in blood. Adult patients had increased frequency of DR3(+) CD8(+) and CD20(+) PBMCs and their CRP levels correlated only with DR3(+) CD8(+) cells.

CONCLUSIONS

In comparison to healthy volunteers, untreated children with IBD have higher percentage of DR3(+) PBMCs than adults with IBD undergoing anti-inflammatory treatment. In most of the investigated PBMCs populations, the frequency of DR3(+) cells is correlated with the level of CRP. We suggest anti-inflammatory treatment may lead to reduction in the frequency of DR3(+) PBMCs. © 2016 International Clinical Cytometry Society.

Systemic and local expression levels of TNF-like ligand 1A and its decoy receptor 3 are increased in primary biliary cirrhosis

BACKGROUND & AIMS

Through a genome-wide association study of a Japanese population, we recently identified TNFSF15, a gene encoding TNF-like ligand 1A (TL1A), as a susceptibility gene for primary biliary cirrhosis (PBC). We investigated the clinical significance of TL1A and one of its receptors, decoy receptor 3 (DcR3), in PBC.

METHODS

We analysed the systemic and local expression of TL1A and DcR3 in 110 PBC patients and 46 healthy controls using enzyme-linked immunosorbent assay, quantitative polymerase chain reaction and immunohistochemical staining.

RESULTS

Serum TL1A levels were significantly increased in PBC patients at both early and late stages as compared with healthy controls, and its levels were significantly decreased in early-stage PBC patients after ursodeoxycholic acid (UDCA) treatment. TL1A was immunohistochemically localized to biliary epithelial cells, Kupffer cells, blood vessels and infiltrating mononuclear cells in the PBC liver. In addition, TL1A messenger RNA expression was increased in the PBC liver as compared with the non-diseased liver. Serum DcR3 levels were also significantly increased in PBC patients, and were significantly decreased after UDCA treatment in early-stage PBC patients.

CONCLUSIONS

These results indicate that TL1A and DcR3 may play an important role in the pathogenesis of PBC.

The role of TL1A and DR3 in autoimmune and inflammatory diseases

TNF-like ligand 1A (TL1A), which binds its cognate receptor DR3 and the decoy receptor DcR3, is an identified member of the TNF superfamily. TL1A exerts pleiotropic effects on cell proliferation, activation, and differentiation of immune cells, including helper T cells and regulatory T cells. TL1A and its two receptors expression is increased in both serum and inflamed tissues in autoimmune diseases such as inflammatory bowel disease (IBD), rheumatoid arthritis (RA), and ankylosing spondylitis (AS). Polymorphisms of the TNFSF15 gene that encodes TL1A are associated with the pathogenesis of irritable bowel syndrome, leprosy, and autoimmune diseases, including IBD, AS, and primary biliary cirrhosis (PBC). In mice, blocking of TL1A-DR3 interaction by either antagonistic antibodies or deletion of the DR3 gene attenuates the severity of multiple autoimmune diseases, whereas sustained TL1A expression on T cells or dendritic cells induces IL-13-dependent small intestinal inflammation. This suggests that modulation of TL1A-DR3 interaction may be a potential therapeutic target in several autoimmune diseases, including IBD, RA, AS, and PBC.

EGFR-driven up-regulation of decoy receptor 3 in keratinocytes contributes to the pathogenesis of psoriasis

Decoy receptor 3 (DcR3) is a soluble receptor of Fas ligand (FasL), LIGHT (TNFSF14) and TNF-like molecule 1A (TL1A) and plays pleiotropic roles in many inflammatory and autoimmune disorders and malignant diseases. In cutaneous biology, DcR3 is expressed in primary human epidermal keratinocytes and is upregulated in skin lesions in psoriasis, which is characterized by chronic inflammation and angiogenesis. However, the regulatory mechanisms of DcR3 over-expression in skin lesions of psoriasis are unknown. Here, we demonstrate that DcR3 can be detected in both dermal blood vessels and epidermal layers of psoriatic skin lesions. Analysis of serum samples showed that DcR3 was elevated, but FasL was downregulated in psoriatic patients compared with normal individuals. Additional cell studies revealed a central role of epidermal growth factor receptor (EGFR) in controlling the basal expression of DcR3 in keratinocytes. Activation of EGFR by epidermal growth factor (EGF) and transforming growth factor (TGF)-α strikingly upregulated DcR3 production. TNF-αenhanced DcR3 expression in both keratinocytes and endothelial cells compared with various inflammatory cytokines involved in psoriasis. Additionally, TNF-α-enhanced DcR3 expression in keratinocytes was inhibited when EGFR was knocked down or EGFR inhibitor was used. The NF-κB pathway was critically involved in the molecular mechanisms underlying the action of EGFR and inflammatory cytokines. Collectively, the novel regulatory mechanisms of DcR3 expression in psoriasis, particularly in keratinocytes and endothelial cells, provides new insight into the pathogenesis of psoriasis and may also contribute to the understanding of other diseases that involve DcR3 overexpression.

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: 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.