The role of TL1A and DR3 in autoimmune and inflammatory diseases

Artemvulactone E isolated from Artemisia vulgaris L. ameliorates lipopolysaccharide-induced inflammation in both RAW264.7 and zebrafish model

Introduction

Natural plants are valuable resources for exploring new bioactive compounds. Artemisia vulgaris L. is a traditional Chinese medicinal herb that has been historically used for treating multiple diseases. Active compounds isolated and extracted from A. vulgaris L. typically possess immunomodulatory and anti-inflammatory properties. Artemvulactone E (AE) is a new sesquiterpene lactone isolated and extracted from A. vulgaris L. with unclear biological activities.

Methods

The immunoregulatory effects of AE on macrophages were assessed by ELISA, RT-qPCR, immunofluorescence, and western blot assay. The effect of AE on lipopolysaccharide (LPS) -relates signaling pathways was examined by western blot assay. In zebrafish models, the larvae were yolk-microinjected with LPS to establish inflammation model and the effect of AE was evaluated by determining the survival rate, heart rate, yolk sac edema size, neutrophils and macrophages infiltration of zebrafish. The interaction between AE and Toll-like receptor 4 (TLR4) was examined by molecular docking and dynamic stimulation.

Results

AE reduced the expression and secretion of pro-inflammatory cytokines (TNF-α and IL-6), inflammatory mediators iNOS and COX-2, as well as decreases the production of intracellular NO and ROS in LPS-stimulated macrophages. In addition, AE exerted its anti-inflammatory effect synergistically by inhibiting MAPK/JAK/STAT3-NF-κB signaling pathways. Furthermore, AE enhanced the survival rate and attenuated inflammatory response in zebrafish embryos treated with LPS. Finally, the molecular dynamics results indicate that AE forms stable complexes with LPS receptor TLR4 through the Ser127 residue, thus completely impairing the subsequent activation of MAPK-NF-κB signaling.

Conclusion

AE exhibits notable anti-inflammatory activity and represents as a potential agent for treating inflammation-associated diseases.

Inflammatory bowel disease and rheumatoid arthritis share a common genetic structure

Background

The comorbidity rate of inflammatory bowel disease (IBD) and rheumatoid arthritis (RA) is high; nevertheless, the reasons behind this high rate remain unclear. Their similar genetic makeup probably contributes to this comorbidity.

Methods

Based on data obtained from the genome-wide association study of IBD and RA, we first assessed an overall genetic association by performing the linkage disequilibrium score regression (LDSC) analysis. Further, a local correlation analysis was performed by estimating the heritability in summary statistics. Next, the causality between the two diseases was analyzed by two-sample Mendelian randomization (MR). A genetic overlap was analyzed by the conditional/conjoint false discovery rate (cond/conjFDR) method.LDSC with specific expression of gene analysis was performed to identify related tissues between the two diseases. Finally, GWAS multi-trait analysis (MTAG) was also carried out.

Results

IBD and RA are correlated at the genomic level, both overall and locally. The MR results suggested that IBD induced RA. We identified 20 shared loci between IBD and RA on the basis of a conjFDR of <0.01. Additionally, we identified two tissues, namely spleen and small intestine terminal ileum, which were commonly associated with both IBD and RA.

Conclusion

Herein, we proved the presence of a polygenic overlap between the genetic makeup of IBD and RA and provided new insights into the genetic architecture and mechanisms underlying the high comorbidity between these two diseases.

TL1A promotes metastasis and EMT process of colorectal cancer

Background

Metastasis is the major problem of colorectal cancer (CRC) and is correlated with the high mortality. Tumor necrosis factor-like cytokine 1A (TL1A) is a novel regulatory factor for inflammatory diseases. This work aimed to investigate the role of TL1A in CRC metastasis.

Method

AOM/DSS-induced mouse model, xenograft tumor model and metastasis murine model were established to mimic the colitis-associated CRC and investigate CRC growth and metastasis in vivo. Colon tissues were assessed by hematoxylin/eosin (HE) staining and immunohistochemistry (IHC). CRC cell metastasis in vivo was observed using in vivo imaging system (IVIS). Cell viability and proliferation were examined using cell counting kit 8 (CCK-8) and EdU experiments. The expression of tumor growth factor β (TGFβ) and metastatic biomarkers were detected using western blotting experiment. The in vitro cell metastasis was measured by Transwell.

Results

Knockdown of TL1A notably suppressed the generation of colonic tumors in azoxymethane/dextran sodium sulfate (AOM/DSS) model, suppressed in vivo CRC cell growth, as well as lung and liver metastasis. The inflammation response and inflammatory cell infiltration in tumor sites were decreased by TL1A depletion. The in vitro CRC cell growth and metastasis was also suppressed by shTL1A, along with altered expression of epithelial mesenchymal transition (EMT) biomarkers. TL1A depletion suppressed the level of the TGF-β1 receptor (TβRI) and phosphorylation of Smad3 in CRC cells. Stimulation with TGF-β recovered the CRC cell migration and invasion that suppressed by shTL1A.

Conclusion

Our work implicated TL1A as a promoter of CRC generation and metastasis and defines TGF-β/Smad3 signaling as mediator of TL1A-regualated CRC cell metastasis.

The Role of Progranulin (PGRN) in the Pathogenesis of Glioblastoma Multiforme

Glioblastoma multiforme (GBM) represents the most common and aggressive malignant form of brain tumour in adults and is characterized by an extremely poor prognosis with dismal survival rates. Currently, expanding concepts concerning the pathophysiology of GBM are inextricably linked with neuroinflammatory phenomena. On account of this fact, the identification of novel pathomechanisms targeting neuroinflammation seems to be crucial in terms of yielding successful individual therapeutic strategies. In recent years, the pleiotropic growth factor progranulin (PGRN) has attracted significant attention in the neuroscience and oncological community regarding its neuroimmunomodulatory and oncogenic functions. This review of the literature summarizes and updates contemporary knowledge about PGRN, its associated receptors and signalling pathway involvement in GBM pathogenesis, indicating possible cellular and molecular mechanisms with potential diagnostic, prognostic and therapeutic targets in order to yield successful individual therapeutic strategies. After a review of the literature, we found that there are possible PGRN-targeted therapeutic approaches for implementation in GBM treatment algorithms both in preclinical and future clinical studies. Furthermore, PGRN-targeted therapies exerted their highest efficacy in combination with other established chemotherapeutic agents, such as temozolomide. The results of the analysis suggested that the possible implementation of routine determinations of PGRN and its associated receptors in tumour tissue and biofluids could serve as a diagnostic and prognostic biomarker of GBM. Furthermore, promising preclinical applications of PGRN-related findings should be investigated in clinical studies in order to create new diagnostic and therapeutic algorithms for GBM treatment.

Crosstalk between alternative splicing and inflammatory bowel disease: Basic mechanisms, biotechnological progresses and future perspectives

BACKGROUND

Alternative splicing (AS) is an omnipresent regulatory mechanism of gene expression that enables the generation of diverse splice isoforms from a single gene. Recently, AS events have gained considerable momentum in the pathogenesis of inflammatory bowel disease (IBD).

METHODS

Our review has summarized the complex process of RNA splicing, and firstly highlighted the potential involved molecules that target aberrant splicing events in IBD. The quantitative transcriptome analyses such as microarrays, next-generation sequencing (NGS) for AS events in IBD have been also discussed.

RESULTS

Available evidence suggests that some abnormal splicing RNAs can lead to multiple intestinal disorders during the onset of IBD as well as the progression to colitis-associated cancer (CAC), including gut microbiota perturbations, intestinal barrier dysfunctions, innate/adaptive immune dysregulations, pro-fibrosis activation and some other risk factors. Moreover, current data show that the advanced technologies, including microarrays and NGS, have been pioneeringly employed to screen the AS candidates and elucidate the potential regulatory mechanisms of IBD. Besides, other biotechnological progresses such as the applications of third-generation sequencing (TGS), single-cell RNA sequencing (scRNA-seq) and spatial transcriptomics (ST), will be desired with great expectations.

CONCLUSIONS

To our knowledge, the current review is the first one to evaluate the potential regulatory mechanisms of AS events in IBD. The expanding list of aberrantly spliced genes in IBD along with the developed technologies provide us new clues to how IBD develops, and how these important AS events can be explored for future treatment.

Astragaloside IV regulates TL1A and NF-κB signal pathway to affect inflammation in necrotizing enterocolitis

AIM

This study aims to explore the possible effect of Astragaloside IV (AS-IV) on necrotizing enterocolitis (NEC) neonatal rat models and verify the possible implication of TNF-like ligand 1 A (TL1A) and NF-κB signal pathway.

METHODS

NEC neonatal rat models were established through formula feeding, cold/asphyxia stress and Lipopolysaccharide (LPS) gavage method. The appearance, activity and skin as well as the pathological status of rats subjected to NEC modeling were assessed. The intestinal tissues were observed after H&E staining. The expression of oxidative stress biomarkers (SOD, MDA and GSH-Px) and inflammatory cytokines (TNF-α, IL-1β and IL-6) were detected by ELISA and qRT-PCR. Western blotting and immunohistochemistry were applied to detect expressions of TL1A and NF-κB signal pathway-related proteins. Cell apoptosis was assessed by TUNEL.

RESULTS

NEC neonatal rat models were established successfully, in which TL1A was highly expressed and NF-κB signal pathway was activated, while TL1A and NF-κB signal pathway can be suppressed by AS-IV treatment in NEC rats. Meanwhile, inflammatory response in intestinal tissues was increased in NEC rat models and AS-IV can attenuate inflammatory response in NEC rats through inhibiting TL1A and NF-κb signal pathway.

CONCLUSION

AS-IV can inhibit TL1A expression and NF-κb signal pathway to attenuate the inflammatory response in NEC neonatal rat models.

New Insights into NF-κB Signaling in Innate Immunity: Focus on Immunometabolic Crosstalks

The nuclear factor kappa B (NF-κB) is a family of transcription factors that, beyond their numberless functions in various cell processes, play a pivotal role in regulating immune cell activation. Two main pathways-canonical and non-canonical-are responsible for NF-κB activation and heterodimer translocation into the nucleus. A complex crosstalk between NF-κB signaling and metabolism is emerging in innate immunity. Metabolic enzymes and metabolites regulate NF-κB activity in many cases through post-translational modifications such as acetylation and phosphorylation. On the other hand, NF-κB affects immunometabolic pathways, including the citrate pathway, thereby building an intricate network. In this review, the emerging findings about NF-κB function in innate immunity and the interplay between NF-κB and immunometabolism have been discussed. These outcomes allow for a deeper comprehension of the molecular mechanisms underlying NF-κB function in innate immune cells. Moreover, the new insights are important in order to perceive NF-κB signaling as a potential therapeutic target for inflammatory/immune chronic diseases.

TL1A induces apoptosis via DR3 in grass carp (Ctenopharyngodon idella)

Tumor necrosis factor like ligand 1A (TL1A), a member of TNF superfamily, regulates inflammatory response and immune defense. TL1A homologues have recently been discovered in fish, but their functions have not been studied. In this study, a TL1A homologue was identified in grass carp (Ctenopharyngodon idella) and its bioactivities were investigated. The grass carp tl1a (Citl1a) gene was constitutively expressed in tissues, with the highest expression detected in the liver. It was upregulated in response to infection with Aeromonas hydrophila. The recombinant CiTL1A was produced in bacteria and was shown to stimulate the expression of il1β, tnfα, caspase 8 and ifnγ in the primary head kidney leucocytes. In addition, co-immunoprecipitation assay revealed that CiTL1A interacted with DR3 and induced apoptosis via activation of DR3. The results demonstrate that TL1A regulates inflammation and apoptosis and is involved in the immune defense against bacterial infection in fish.

Increased Serum Levels of Tumor Necrosis Factor-like Ligand 1A in Atopic Dermatitis

Atopic dermatitis (AD) is a common chronic skin disease with pruritus, affecting 5-20% of the population in developed countries. Though its cause varies from genetic polymorphisms to the environmental factors, the T-helper (Th) 2 inflammation is one of the main characteristic pathoses. TNF superfamily ligand A (TL1A) is a recently discovered cytokine, which is released by various immune cells and reported to have an ability to stimulate Th1, Th2, and Th17 responses. Its association was investigated in chronic inflammatory disease, such as rheumatoid arthritis, inflammatory bowel disease, and psoriasis. However, its role on AD is unclear. To elucidate the association of TL1A in AD, we measured the serum TL1A levels in AD patients and healthy controls and performed the immunohistochemistry of TL1A. The result showed that the serum TL1A levels were higher in AD patients than healthy controls, and they positively correlated with the serum immunoglobulin E levels, serum Lactate dehydrogenase, and the number of eosinophils in peripheral blood. The immunohistochemistry of TL1A also showed TL1A expression in epithelium of AD samples. Because previous studies indicate TL1A has a certain role as an inflammation enhancer in Th2 and/or Th17 polarized disease, TL1A in AD may also has a role as an inflammation generator.

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.

Genome-wide association study identifies TNFSF15 associated with childhood asthma

BACKGROUND

Genome-wide association studies (GWASs) of asthma have identified several risk alleles and loci, but most have been conducted in individuals with European-ancestry. Studies in Asians, especially children, are still lacking. We aimed to identify susceptibility loci by performing the first GWAS of asthma in Korean children with persistent asthma.

METHODS

We used a discovery set of 741 children with persistent asthma as cases and 589 healthy children and 551 healthy adults as controls to perform a GWAS. We validated our GWAS findings using UK Biobank data. We then used the Genotype-Tissue Expression database to identify expression quantitative trait loci of candidate variants. Finally, we quantified proteins of genes associated with asthma.

RESULTS

Variants at the 17q12-21 locus and SNPs in CYBRD1 and TNFSF15 genes were associated with persistent childhood asthma at genome-wide thresholds of significance. Four SNPs in the TNFSF15 gene were also associated with childhood-onset asthma in British white participants in the UK Biobank data. The asthma-associated rs7856856-C allele, the lead SNP, was associated with decreased TNFSF15 expression in whole blood and in arteries. Korean children with asthma had lower serum TNFSF15 levels than controls, and those with the asthma risk rs7856856-CC genotype exhibited the lowest serum TNFSF15 levels overall, especially asthmatic children.

CONCLUSIONS

Our GWAS of persistent childhood asthma with allergic sensitization identified a new susceptibility gene, TNFSF15, and replicated associations at the 17q12-21 childhood-onset asthma locus. This novel association may be mediated by reduced expression of serum TNFSF15 and loss of suppression of angiogenesis.

NF-κB: At the Borders of Autoimmunity and Inflammation

The transcription factor NF-κB regulates multiple aspects of innate and adaptive immune functions and serves as a pivotal mediator of inflammatory response. In the first part of this review, we discuss the NF-κB inducers, signaling pathways, and regulators involved in immune homeostasis as well as detail the importance of post-translational regulation by ubiquitination in NF-κB function. We also indicate the stages of central and peripheral tolerance where NF-κB plays a fundamental role. With respect to central tolerance, we detail how NF-κB regulates medullary thymic epithelial cell (mTEC) development, homeostasis, and function. Moreover, we elaborate on its role in the migration of double-positive (DP) thymocytes from the thymic cortex to the medulla. With respect to peripheral tolerance, we outline how NF-κB contributes to the inactivation and destruction of autoreactive T and B lymphocytes as well as the differentiation of CD4⁺-T cell subsets that are implicated in immune tolerance. In the latter half of the review, we describe the contribution of NF-κB to the pathogenesis of autoimmunity and autoinflammation. The recent discovery of mutations involving components of the pathway has both deepened our understanding of autoimmune disease and informed new therapeutic approaches to treat these illnesses.

Co-Stimulatory Bispecific Antibodies Induce Enhanced T Cell Activation and Tumor Cell Killing in Breast Cancer Models

Although T cell-recruiting CD3-binding bispecific antibodies (BiMAb) have been proven to be clinically effective for hematologic malignancies, the success of BiMAb targeting solid tumor-associated antigens (TAA) in carcinomas so far remains poor. We reasoned that provision of co-stimulatory BiMAb in combination with αTAA-αCD3 BiMAb would boost T cell activation and proliferative capacity, and thereby facilitate the targeting of weakly or heterogeneously expressed tumor antigens. Various αTAA-αCD3 and αTAA-αCD28 BiMAb in a tetravalent IgG1-Fc based format have been analyzed, targeting multiple breast cancer antigens including HER2, EGFR, CEA, and EpCAM. Moreover, bifunctional fusion proteins of αTAA-tumor necrosis factor ligand (TNFL) superfamily members including 4-1BBL, OX40L, CD70 and TL1A have been tested. The functional activity of BiMAb was assessed using co-cultures of tumor cell lines and purified T cells in monolayer and tumor spheroid models. Only in the presence of tumor cells, αTAA-αCD3 BiMAb activated T cells and induced cytotoxicity in vitro, indicating a strict dependence on cross-linking. Combination treatment of αTAA-αCD3 BiMAb and co-stimulatory αTAA-αCD28 or αTAA-TNFL fusion proteins drastically enhanced T cell activation in terms of proliferation, activation marker expression, cytokine secretion and tumor cytotoxicity. Furthermore, BiMAb providing co-stimulation were shown to reduce the minimally required dose to achieve T cell activation by at least tenfold. Immuno-suppressive effects of TGF-β and IL-10 on T cell activation and memory cell formation could be overcome by co-stimulation. BiMAb-mediated co-stimulation was further augmented by immune checkpoint-inhibiting antibodies. Effective co-stimulation could be achieved by targeting a second breast cancer antigen, or by targeting fibroblast activation protein (FAP) expressed on another target cell. In tumor spheroids derived from pleural effusions of breast cancer patients, co-stimulatory BiMAb were essential for the activation tumor-infiltrating lymphocytes and cytotoxic anti-tumor responses against breast cancer cells. Taken together we showed that co-stimulation significantly potentiated the tumoricidal activity of T cell-activating BiMAb while preserving the dependence on TAA recognition. This approach could provide for a more localized activation of the immune system with higher efficacy and reduced peripheral toxicities.

Mechanisms of anti-viral Cytotoxic CD4 T cell differentiation

Cytotoxic CD4 T lymphocytes (CD4-CTL) are important in anti-viral immunity. For example, we have previously shown that in mice, CD4-CTL are important to control ectromelia virus (ECTV) infection. How viral infections induce CD4-CTL responses remains incompletely understood. Here we demonstrate that not only ECTV but also vaccinia virus and Lymphocytic Choriomeningitis virus induce CD4-CTL, but that the response to ECTV is stronger. Using ECTV, we also demonstrate that in contrast to CD8-CTL, CD4-CTL differentiation requires constant virus replication and ceases once the virus is controlled. We also show that Major Histocompatibility Complex Class II molecules on CD11c⁺ cells are required for CD4-CTL differentiation and for mousepox resistance. Transcriptional analysis indicated that anti-viral CD4-CTL and non-cytolytic T Helper 1 (Th1) CD4 T cells have similar transcriptional profiles, suggesting that CD4-CTL are terminally differentiated classical Th1 cells. Interestingly, CD4-CTL and classical Th1 cells expressed similar mRNA levels of the transcription factors ThPOK and GATA-3, necessary for CD4 T cell linage commitment; and Runx3, required for CD8 T cell development and effector function. However, at the protein level, CD4-CTL had higher levels of the three transcription factors suggesting that further post-transcriptional regulation is required for CD4-CTL differentiation. Finally, using CRISPR-Cas9 deletion of Runx3 in CD4 T cells, we demonstrate that the development of CD4-CTL but not of classical Th1 CD4 T cells requires Runx3 following ECTV infection. These results further our understanding of the mechanisms of CD4-CTL differentiation during viral infection and the role of post-transcriptionally regulated Runx3 in this process. IMPORTANCE While it is well established that cytotoxic CD4 T cells (CD4-CTL) directly contribute to viral clearance, it remains unclear how CD4-CTL are induced. We now show that CD4-CTL require sustained antigen presentation and are induced by CD11c-expressing antigen presenting cells. Moreover, we show that CD4-CTL are derived from the terminal differentiation of classical T helper 1 (Th1) subset of CD4 cells. Compared to Th1 cells, CD4-CTL upregulate protein levels of the transcription factors ThPOK, Runx3 and GATA-3 post-transcriptionally. Deletion of Runx3 in differentiated CD4 T cells prevents CD4-CTL but not of classical Th1 cells. These results advance our knowledge of how CD4-CTL are induced during viral infection.

The relationship between TNF-like protein 1A and coronary artery aneurysms in children with Kawasaki disease

Kawasaki disease (KD) is an acute, systemic vasculitis of unknown etiology that occurs predominantly in infants and children, and the most crucial complication of KD is coronary artery aneurysm (CAA). Tumor necrosis factor (TNF)-like protein 1A (TL1A) is a member of the TNF superfamily, which possesses the ability of maintaining vascular homeostasis and regulating immune responses. This study aimed to examine serum TL1A levels in KD patients, and to investigate the relationship between TL1A and CAAs in children with KD. Blood samples were recruited from 119 KD patients, 35 febrile controls (FCs), and 37 healthy controls (HCs). The KD group was further divided into KD with CAAs (KD-CAAs) and KD non-CAAs (KD-NCAAs) groups. Serum TL1A levels were measured using enzyme-linked immunosorbent assays, and clinical parameters were collected from KD patients. Serum TL1A levels of KD patients in the acute phase of KD were significantly higher than in the FC and HC groups. In particular, serum TL1A levels were substantially increased in the KD-CAA group compared with the KD-NCAA group. Furthermore, TL1A levels in the KD group were positively correlated with the duration of fever and the time point of IVIG and WBC levels, but negatively correlated with levels of RBC, Hb and albumin. TL1A might be involved in KD-associated vasculitis and in the development of CAAs.

Multiplex gene targeting in the mouse embryo using a Cas9-Cpf1 hybrid guide RNA

CRISPR-Cas systems, including Cas9 and Cpf1 (Cas12a), are promising tools for generating gene knockout mouse models. Unlike Cas9, Cpf1 can generate multiple crRNAs from a single concatemeric crRNA precursor, which is favorable for multiplex gene editing. Recently, a hybrid guide RNA (hgRNA) system employing both Cas9 and Cpf1 was developed for multiplex gene editing. As the crRNA of Cpf1 was linked to the 3' end of the sgRNA for Cas9, it can be split into separate guide RNAs by Cpf1. To examine whether this Cas9-Cpf1 hybrid system is suitable for multiplex gene knockouts in the mouse embryo, we generated an hgRNA that simultaneously targets the mouse Il10ra gene by Cas9 and mouse Dr3 (or Tnfrsf25, death receptor3) gene by Cpf1. The expression of hgRNA from a single promoter induced significant indels at each gene in cultured mouse cells upon the co-expression of both Cas9 and Cpf1. Interestingly, the hgRNA exhibited comparable Cas9-mediated indel activity without Cpf1 expression. Similarly, when the hgRNA was co-microinjected with both Cas9 and Cpf1 mRNAs into mouse zygotes at the pronuclear stage, founder mice were generated harboring mutations in both the Il10ra and Dr3 genes. However, when Cas9 mRNA was used alone without Cpf1 mRNA, the mouse Il10ra gene targeting was significantly decreased. These results indicate that the hgRNA system is a possible tool for multiplex gene targeting in the mouse embryo.

An insight into the mechanism and molecular basis of dysfunctional immune response involved in cholestasis

Cholestasis is one of the most common clinical symptom of liver diseases. If patients do not receive effective treatment, cholestasis can evolve into liver fibrosis, cirrhosis and ultimately liver failure requiring liver transplantation. Currently, only ursodeoxycholic acid, obeticholic acid and bezafibrate are FDA-approved drugs, thereby requiring a breakthrough in new mechanisms and therapeutic development. Inflammation is one of the common complications of cholestasis. Hepatic accumulation of toxic hydrophobic bile acids is a highly immunogenic process involving both resident and immigrating immune cells. And the resulting inflammation may further aggravate hepatocyte injury. Though, great investigations have been made in the immune responses during cholestasis, the relationship between immune responses and cholestasis remains unclear. Moreover, scarce reviews summarize the immune responses during cholestasis and the efficacy of therapies on immune response. The main purpose of this paper is to review the existing literature on dysfunctional immune response during cholestasis and the effect of treatment on immune response which may provide an insight for researchers and drug development.

The haplotypes of various TNF related genes associated with scleritis in Chinese Han

Background

Several studies have stated that TNF-α participates in the pathogenesis of scleritis, but also in several systemic autoimmune diseases and vasculitis, of which some are associated with scleritis. Earlier GWAS and SNP studies have confirmed that multiple SNPs of TNF related genes are associated with many immune-mediated disorders. The purpose of this study was to examine the association of TNF related gene polymorphisms with scleritis in Chinese Han. A case-control study was carried out in 556 non-infectious scleritis cases and 742 normal controls. A total of 28 single-nucleotide polymorphisms (SNPs) were genotyped by the iPLEXGold genotyping assay.

Results

No significant correlations were seen between the individual SNPs in the TNF related genes and scleritis. Haplotype analysis showed a significantly decreased frequency of a TNFAIP3 TGT haplotype (order of SNPs: rs9494885, rs3799491, rs2230926) (Pc = 0.021, OR = 0.717, 95% CI = 0.563–0.913) and a significantly increased frequency of a TNFSF4 GT haplotype (order of SNPs: rs3850641, rs704840) (Pc = 0.004, OR = 1.691, 95% CI = 1.205–2.372) and TNFSF15 CCC haplotype (order of SNPs: rs6478106, rs3810936, rs7865494) (Pc = 0.012, OR = 1.662, 95% CI = 1.168–2.363) in patients with scleritis as compared with healthy volunteers.

Conclusions

This study reveals that a TGT haplotype in TNFAIP3 may be a protective factor for the development of scleritis and that a GT haplotype in TNFSF4 and a CCC haplotype in TNFSF15 may be risk factors for scleritis in Chinese Han.

Genetic characterization of Addison's disease in Bearded Collies

BACKGROUND

Primary hypoadrenocorticism (or Addison's disease, AD) is an autoimmune disease that results in destruction of the adrenal cortex and consequent adrenal insufficiency. The disease has been described in purebred and mixed breed dogs, although some breeds, including the Bearded Collie, are at increased risk for AD. Candidate gene approaches have yielded few associations that appear to be breed-specific. A single other genome-wide association study reported no significant regions of association for AD in Standard Poodles. The present study aimed to identify genomic regions of association for canine AD in Bearded Collies.

RESULTS

Our study consists of the first genome-wide association analysis to identify a genome-wide significant region of association with canine AD (CFA18). Peaks of suggestive association were also noted on chromosomes 11, 16 and 29. Logistic regression analysis supported an additive effect of risk genotypes at these smaller effect loci on the probability of disease associated with carrying a risk genotype on CFA18. Potential candidate genes involved in adrenal steroidogenesis, regulation of immune responses and/or inflammation were identified within the associated regions of chromosomes 11 and 16. The gene-poor regions of chromosomes 18 and 29 may, however, harbor regulatory sequences that can modulate gene expression and contribute to disease susceptibility.

CONCLUSION

Our findings support the polygenic and complex nature of canine AD and identified a strongly associated locus on CFA18 that, when combined with three other smaller effect loci, was predictive of disease. The results offer progress in the identification of susceptibility loci for canine AD in the Bearded Collie. Further studies are needed to confirm association with the suggested candidate genes and identify actual causative mutations involved with AD susceptibility in this breed.

An adverse outcome pathway for immune-mediated and allergic hepatitis: a case study with the NSAID diclofenac

Many drugs have the potential to cause drug-induced liver injury (DILI); however, underlying mechanisms are diverse. The concept of adverse outcome pathways (AOPs) has become instrumental for risk assessment of drug class effects. We report AOPs specific for immune-mediated and drug hypersensitivity/allergic hepatitis by considering genomic, histo- and clinical pathology data of mice and dogs treated with diclofenac. The findings are relevant for other NSAIDs and drugs undergoing iminoquinone and quinone reactive metabolite formation. We define reactive metabolites catalyzed by CYP monooxygenase and myeloperoxidases of neutrophils and Kupffer cells as well as acyl glucuronides produced by uridine diphosphoglucuronosyl transferase as molecular initiating events (MIE). The reactive metabolites bind to proteins and act as neo-antigen and involve antigen-presenting cells to elicit B- and T-cell responses. Given the diverse immune systems between mice and dogs, six different key events (KEs) at the cellular and up to four KEs at the organ level are defined with mechanistic plausibility for the onset and progression of liver inflammation. With mice, cellular stress response, interferon gamma-, adipocytokine- and chemokine signaling provided a rationale for the AOP of immune-mediated hepatitis. With dogs, an erroneous programming of the innate and adaptive immune response resulted in mast cell activation; their infiltration into liver parenchyma and the shift to M2-polarized Kupffer cells signify allergic hepatitis and the occurrence of granulomas of the liver. Taken together, diclofenac induces divergent immune responses among two important preclinical animal species, and the injury pattern seen among clinical cases confirms the relevance of the developed AOP for immune-mediated hepatitis.

Effects of tumor necrosis factor-like ligand 1A (TL1A) on imiquimod-induced psoriasiform skin inflammation in mice

TL1A, as a master regulatory cytokine, plays a key role in the development of diverse T-cell-mediated inflammatory and autoimmune diseases. Our study is to further understand the roles of TL1A in the pathogenic mechanism of psoriasis and to find a possible new therapeutic strategy in the treatment of psoriasis. The direct effects of TL1A injection in mice skin and the therapeutic effects of TL1A blockade in imiquimod (IMQ)-induced psoriasis-like mouse model were researched in this study. First, we found that the expressions of TL1A in IMQ-treated lesions were significantly higher than Vaseline control group. And then, the results showed that TL1A injection exacerbated the psoriasiform phenotype on IMQ-treated skin (including clinical score, epidermal thickness changes, and Baker score) by increasing the number of T cells, neutrophils, and DCs, and upregulating the mRNA expression of IFN-γ and IL-17. However, anti-TL1A mAb can alleviate psoriasis-like lesions in clinical and effectively improved the histopathologic changes in IMQ-induced psoriasis-like mice after treatment. Moreover, anti-TL1A mAb also reduced the number of infiltrated CD3⁺ T cells, MPO⁺ neutrophils, and CD11c⁺ DCs in psoriasis-like lesions, and obviously decreased the expression of IFN-γ and IL-17 in psoriasis-like lesions. Data suggested that TL1A might be involved in the pathogenesis of psoriasis, and targeting TL1A by anti-TL1A mAb might provide a solid foundation and novel therapeutic sight in the treatment of psoriasis.

The TL1A-DR3 Axis Selectively Drives Effector Functions in Human MAIT Cells

Mucosal-associated invariant T (MAIT) cells are semi-invariant T cells specifically recognizing riboflavin derivatives that are synthesized by many bacteria and fungi presented by MHC class I-related MR1 molecules. Accumulating evidence, however, indicates that MAIT cell functions are inducible by cytokine stimuli in the absence of TCR ligation, identifying MAIT cells as innate sentinels in inflammatory environments. In this study, we demonstrate that death receptor 3 (DR3), a member of the TNFR superfamily, is ex vivo expressed and predominantly upregulated on the surface of human MAIT cells by innate cytokine stimulation. In turn, the DR3 ligand TNF-like protein 1A (TL1A) licenses innate TNF-α production in the absence of cognate triggers, being sufficient to promote activation of primary endothelial cells in vitro. TL1A further amplifies synthesis of IFN-γ and granzyme B in the presence of otherwise weak innate stimuli and strongly augments polyfunctionality. Mechanistically, TL1A potentiates T-bet expression, early NF-κB, and late p38 MAP kinase phosphorylation, with the latter being indispensable for TNF-α production by MAIT cells. Of note, endogenous TL1A is also rapidly released from PBMC cultures in response to bacterial triggering, thereby equally augmenting Ag-specific MAIT cell effector functions. In summary, to our knowledge, we identify a new inflammatory mechanism in MAIT cells linking the DR3/TL1A axis with amplification of TCR-dependent and -independent effector functions, particularly inducing excessive innate TNF-α production. Given that both TL1A and TNF-α are abundantly present at sites of chronic inflammation, the contribution of MAIT cells in such scenarios needs to be determined.

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.

Activation of DR3 signaling causes loss of ILC3s and exacerbates intestinal inflammation

TNF-like ligand 1 A (TL1A) and death receptor 3 (DR3) are a ligand-receptor pair involved in the pathogenesis of inflammatory bowel disease. Group 3 innate lymphoid cells (ILC3s) regulate intestinal immunity and highly express DR3. Here, we report that activation of DR3 signaling by an agonistic anti-DR3 antibody increases GM-CSF production from ILC3s through the p38 MAPK pathway. GM-CSF causes accumulation of eosinophils, neutrophils and CD11b⁺CD11c⁺ myeloid cells, resulting in loss of ILC3s from the intestine in an IL-23-dependent manner and exacerbating colitis. Blockade of GM-CSF or IL-23 reverses anti-DR3 antibody-driven ILC3 loss, whereas overexpression of IL-23 induces loss of ILC3s in the absence of GM-CSF. Neutralization of TL1A by soluble DR3 ameliorates both DSS and anti-CD40 antibody-induced colitis. Moreover, ILC3s are required for the deleterious effect of anti-DR3 antibodies on innate colitis. These findings clarify the process and consequences of DR3 signaling-induced intestinal inflammation through regulation of ILC3s.

Activation of the DR3-TL1A Axis in Donor Mice Leads to Regulatory T Cell Expansion and Activation With Reduction in Graft-Versus-Host Disease

Death receptor 3 (DR3) is a tumor necrosis factor receptor superfamily member (TNFRSF25), which is minimally expressed on resting conventional T cells (though readily inducible upon cell activation), yet highly expressed on resting FoxP3⁺ regulatory T cells (Treg). We recently demonstrated that activation of DR3 with an agonistic antibody (4C12) leads to selective expansion and activation of Treg in healthy mice and suppression of graft-versus-host disease (GVHD) in recipient mice when donor mice are treated. However, given the long antibody half-life and concomitant safety concerns, along with the lack of a humanized agonistic antibody to DR3, both human and murine fusion proteins incorporating the natural DR3 ligand TL1A (TL1A-Ig) have been developed. Herein, we show that DR3 activation with 4C12 or with TL1A-Ig, with or without the addition of low dose IL-2 to the treatment regimen, led to a significant expansion of murine Treg in spleen, lymph nodes, and peripheral blood. Bioluminescent imaging revealed peak Treg expansion around day 7-8, with return to near baseline after 2-3 weeks. In addition to expansion, all DR3 agonist treatment regimens led to increased activation of Tregs, with significant upregulation of the activation markers ICOS, KLRG-1, PD-1, and CD103, and the proliferation marker Ki-67. The near absence of activated Treg populations in control treated spleens was also detected on tSNE analysis of flow cytometry data. Subtly different patterns of splenic Treg activation by the different DR3 agonists were noted in both tSNE analysis of flow cytometry data and RNA-sequencing analysis. However, upregulation of gene transcripts which play important roles in cell proliferation, trafficking, activation, and effector function were observed regardless of the DR3 agonist treatment regimen used. In the major MHC-mismatch model of hematopoietic cell transplantation, DR3 agonist-mediated expansion and activation of Tregs in donor mice led to a significant improvement in GVHD in recipient mice. These data provide important preclinical information regarding the outcome of DR3 activation with an agonistic antibody or natural ligand and provide insight into the therapeutic use of this approach to reduce GVHD in recipients and improve outcomes of hematopoietic cell transplantation.

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.

TL1A modulates the severity of colitis by promoting Th9 differentiation and IL-9 secretion

AIMS

TL1A was reported to contribute to the susceptibility to ulcerative colitis (UC). However, the molecular mechanisms of TL1A in UC development are poorly understood. We aimed to investigate the role of TL1A in colitis, and reveal the regulatory mechanism of TL1A in chronic colitis development.

MAIN METHODS

Wild-type mice and transgenic mice with overexpressing TL1A in lymphocytes were used to construct chronic DSS colitis models. To investigate the molecular mechanism in vitro, CD4⁺ T cells were sorted from spleens and mesenteric lymph node cells to induce Th9 cells. Biopsy specimens from ulcerative colitis patients were collected for in vivo validation.

KEY FINDINGS

The elevated TL1A expression in chronic DSS colitis models exacerbated intestinal inflammation. The differentiation of Th9 cells, IL-9 secretion and production of TGF-β, IL-4 and PU.1 was significantly enhanced in transgenic mice with TL1A overexpression. In vitro results showed that TL1A enhanced the Th9 cells, IL-9 and PU.1 production, while TL1A antibodies inhibited their production. In human translational studies, patients with ulcerative colitis with elevated TL1A expression also exhibited more serious inflammation with higher levels of Th9 cells, IL-9 and PU.1 expression.

SIGNIFICANCE

We presented a possible mechanism of TL1A in UC development that TL1A may promote the differentiation of Th9 cells and enhanced IL-9 secretion by up-regulating the expression of TGF-β, IL-4 and PU.1, which provided a novel perspective to study the UC pathogenesis, and indicated that targeting of TL1A signal pathway may by a likely strategy for the treatment of chronic colitis.

The role of progranulin (PGRN) in the modulation of anti-inflammatory response in asthma

Asthma is one of the most common chronic diseases. Epidemiological studies show that asthma will develop among around 40% of children under six years old with symptoms of bronchial obstruction. Diagnosis of asthma is complicated, especially in the paediatric population. As a result, a lot of research is being carried out to establish the pathophysiology and to find new biomarkers of this disease. Progranulin (PGRN) is a recently discovered growth factor with many biological functions. PGRN has anti-inflammatory properties because it inhibits neutrophil degranulation and blocks tumor necrosis factor α (TNF-α) transmission. The underlying mechanisms are still being researched, but TNF-α is considered to be a cytokine responsible for neutrophilic inflammation in the airways and bronchial hyperresponsiveness. Therefore, PGRN, by lowering TNF-α concentration and stimulating regulatory T-cell (Treg) proliferation, relieves symptoms of bronchial inflammatory diseases. This article attempts to verify the current knowledge about basic pathophysiological mechanisms in asthma. We also summarise the most recent research advances in the role of PGRN in the respiratory system.

Overexpression of Tumor Necrosis Factor-Like Ligand 1 A in Myeloid Cells Aggravates Liver Fibrosis in Mice

Macrophages are the master regulator of the dynamic fibrogenesis-fibrosis resolution paradigm. TNF-like ligand 1 aberrance (TL1A) was found to be able to induce intestinal inflammation and fibrosis. Furthermore, significantly increased TL1A had been detected in liver tissues and mononuclear cells of patients with primary biliary cirrhosis (PBC). This study was to investigate the effect of myeloid cells with constitutive TL1A expression on liver fibrogenesis. We found that TL1A expressions in liver tissues and macrophages were significantly increased in mice with liver fibrosis induced by injection of carbon tetrachloride (CCl₄). TL1A overexpression in myeloid cells induced liver function injury, accelerated the necrosis and apoptosis of hepatocytes, recruited macrophages, and promoted activation of hepatic stellate cells (HSCs) and fibrosis. In vitro results of our study showed that TL1A overexpression in macrophages promoted secretion of platelet-derived growth factor-BB (PDGF-BB), tumor necrosis factor-α (TNF-α), and interleukin-1β (IL-1β). Culturing macrophages with TL1A overexpression could accelerate the activation and proliferation of primary HSCs. These results indicated that constitutive TL1A expression in myeloid cells exacerbated liver fibrosis, probably through macrophage recruitment and secretion of proinflammatory and profibrotic cytokines.

The TNF Family of Ligands and Receptors: Communication Modules in the Immune System and Beyond

The tumor necrosis factor (TNF) and TNF receptor (TNFR) superfamilies (TNFSF/TNFRSF) include 19 ligands and 29 receptors that play important roles in the modulation of cellular functions. The communication pathways mediated by TNFSF/TNFRSF are essential for numerous developmental, homeostatic, and stimulus-responsive processes in vivo. TNFSF/TNFRSF members regulate cellular differentiation, survival, and programmed death, but their most critical functions pertain to the immune system. Both innate and adaptive immune cells are controlled by TNFSF/TNFRSF members in a manner that is crucial for the coordination of various mechanisms driving either co-stimulation or co-inhibition of the immune response. Dysregulation of these same signaling pathways has been implicated in inflammatory and autoimmune diseases, highlighting the importance of their tight regulation. Investigation of the control of TNFSF/TNFRSF activities has led to the development of therapeutics with the potential to reduce chronic inflammation or promote anti-tumor immunity. The study of TNFSF/TNFRSF proteins has exploded over the last 30 yr, but there remains a need to better understand the fundamental mechanisms underlying the molecular pathways they mediate to design more effective anti-inflammatory and anti-cancer therapies.

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.

Tumor Necrosis Factor Ligand-Related Molecule 1A Regulates the Occurrence of Colitis-Associated Colorectal Cancer

BACKGROUND

Tumor necrosis factor ligand-related molecule 1 A (TLlA) is closely related to the occurrence and development of inflammatory bowel disease.

AIMS

We aimed to explore whether TLlA was involved in the occurrence of colitis-associated colorectal cancer (CAC).

METHODS

Firstly, azoxymethane (AOM) and dextran sulfate sodium (DSS) were used to construct the CAC mice model in wild-type (WT) and TL1A transgenic (Tg) mice with TL1A high expression. The histopathological analysis was used for the evaluation of inflammation level, and the immunohistochemistry staining analysis was used to test the expression and location of proliferating cell nuclear antigen (PCNA) and β-catenin. Secondly, the HCT116 and HT29 cell lines were used for knockdown of TL1A gene for further assay including cell viability, cell clone, cell apoptosis and matrigel invasion. Western blot were used for quantitative protein expression of β-catenin and downstream oncogenes including c-myc and Cyclin D1 after knockdown of TL1A gene.

RESULTS

The evaluation of inflammation level showed that the disease activity index score and tumor formation rate were significantly higher in AOM + DSS/Tg group than that in AOM + DSS/WT group. The expression of PCNA, β-catenin, c-myc, and Cyclin D1 in AOM + DSS/Tg group was significantly higher than that in AOM + DSS/WT group. The cell experiment showed that TL1A knockdown inhibited the cell proliferation, invasion, and migration. Moreover, the expression of c-myc and Cyclin D1 was significantly decreased after TL1A knockdown.

CONCLUSIONS

TL1A can induce tumor cell proliferation and promote the occurrence of CAC by activating Wnt/β-catenin pathway.

TNFSF15 is likely a susceptibility gene for systemic lupus erythematosus

We aim to explore the correlation of TNFSF15 genetic polymorphisms with susceptibility to systemic lupus erythematosus (SLE). This study enrolled SLE patients and healthy individuals to detect three single nucleotide polymorphisms (SNPs) of TNFSF15 (rs3810936, rs6478108 and rs4979462) through using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) to analyze the possible association of these three SNPs with the risk of SLE and the mRNA level of TNFSF15 was quantified by real-time PCR. The rs3810936 T allele carrier greatly decreased risk of SLE (OR = 0.620, 95% CI = 0.454-0.849, P = 0.003), while the risk of SLE for rs4979462 T allele carrier was significantly increased (OR = 1.66, 95% CI = 1.243-2.218, P < 0.001). The mRNA level of TNFSF15 was obviously higher in SLE patients, and specifically, the patients who carried the CC genotype of TNFSF15 rs3810936 had a higher TNFSF15 mRNA, but the rs4979462 CC genotype carriers appeared to be associated with the decreased TNFSF15 mRNA (all P < 0.05). Besides, the genotypes of rs3810936 and rs4979462 of TNFSF15 were significantly associated with butterfly rash, arthritis, serositis, renal nephritis, hematological disorder, immunological disorder and positive antinuclear antibody (ANA) of SLE patients (all P < 0.05). CCT and CTT haplotypes were risk factors of SLE, but CCC and TTT were protective factors of SLE (all P < 0.05). Logistic regression analysis showed that rs3810936 and rs4979462 of TNFSF15, histories of chilblain and wet living environment were independently associated with the risk of SLE (all P < 0.05).The current results suggested that TNFSF15 (rs3810936 and rs4979462) SNPs may confer susceptibility to SLE risk, which were significantly associated with the clinical phenotypes of SLE.

ShDcR3 sensitizes TRAIL-resistant HCC cells by inducing caspase-dependent apoptosis while suppressing NF-κB dependent cFLIPL expression

Evidence has shown that most hepatocellular carcinoma (HCC) cells are resistant to tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL)-mediated apoptosis. However, the molecular mechanisms underlying TRAIL-mediated apoptosis resistance are not well understood. In this study, we reported that downregulation of Decoy receptor 3 (DcR3) expression by lentiviral vectors carrying shRNA against DcR3 (LV-ShDcR3, shDcR3) in Huh7 both greatly enhanced TRAIL-mediated apoptosis and reduced cell proliferation capability. In addition, silencing DcR3 resulted in upregulation of the cell apoptotic regulators including Bid, caspase-3, and caspase-8. Caspase inhibitors inhibited shDcR3-mediated cell death, which indicated that downregulation of DcR3 expression in Huh7 cells increased TRAIL-induced caspase-dependent apoptotic cell death. Furthermore, although the knockdown of DcR3 altered the expression of some Bcl-2- and IAP-family proteins, this change was inhibited by pretreatment with a pancaspase inhibitor, which indicated the cytotoxic effect of shDcR3 was not due to the expression of these proteins. In contrast, shDcR3 significantly inhibited TRAIL-induced transcription factor nuclear κB (NF-κB) activation through the IκB kinase (IKK) pathway, as well as inhibited TRAIL-induced increases in FLICE-inhibitory protein long form (cFLIP_L) expression at the transcriptional level. Silencing cFLIP_L expression mimicked the cytotoxic effect of shDcR3 on TRAIL-mediated cell apoptosis. Moreover, overexpression of cFLIP_L effectively prevented the increase in cell apoptosis in Huh7 cells co-treated with TRAIL and shDcR3. Taken together, our findings indicated that silencing DcR3 sensitizes TRAIL-mediated apoptosis in HCC cells by inhibiting NF-κB.

TL1A blocking ameliorates intestinal fibrosis in the T cell transfer model of chronic colitis in mice

Tumor necrosis factor like cytokine 1A (TL1A) is a member of the TNF superfamily. Accumulating evidence demonstrated the importance of TL1A in the pathogenesis of inflammatory bowel disease (IBD) and suggested a potential role of TL1A blocking in IBD therapy. Here we aimed to explore whether the anti-TL1A antibody could ameliorate intestinal inflammation and fibrosis in IBD. A T cell transfer model of chronic colitis was induced by intraperitoneal injection of CD4⁺CD45RB^high naive T cells isolated from either C57BL/6 wild type (WT) mice or LCK-CD2-Tl1a-GFP transgenic (L-Tg) mice into recombinase activating gene-1-deficient (RAG^-/-) mice. The colitis model mice were treated prophylactically or therapeutically with anti-Tl1a antibody or IgG isotype control. Haematoxylin and eosin staining (H&E staining), Masson's trichrome staining (MT staining) and sirius red staining were used to detect histopathological changes in colonic tissue; immunohistochemical staining was used to detect the expressions of collagen I, collagen III, TIMP1, vimentin, α-SMA and TGF-β1/Smad3. Results showed that anti-Tl1a antibody could reduce intestinal inflammation and fibrosis by inhibiting the activation of intestinal fibroblasts and reducing the collagen synthesis in the T cell transfer model of chronic colitis. The mechanism may be related to the inhibition of TGF-1/Smad3 signaling pathway.

The pathogenesis of diclofenac induced immunoallergic hepatitis in a canine model of liver injury

Hypersensitivity to non-steroidal anti-inflammatory drugs is a common adverse drug reaction and may result in serious inflammatory reactions of the liver. To investigate mechanism of immunoallergic hepatitis beagle dogs were given 1 or 3 mg/kg/day (HD) oral diclofenac for 28 days. HD diclofenac treatment caused liver function test abnormalities, reduced haematocrit and haemoglobin but induced reticulocyte, WBC, platelet, neutrophil and eosinophil counts. Histopathology evidenced hepatic steatosis and glycogen depletion, apoptosis, acute lobular hepatitis, granulomas and mastocytosis. Whole genome scans revealed 663 significantly regulated genes of which 82, 47 and 25 code for stress, immune response and inflammation. Immunopathology confirmed strong induction of IgM, the complement factors C3&B, SAA, SERPING1 and others of the classical and alternate pathway. Alike, marked expression of CD205 and CD74 in Kupffer cells and lymphocytes facilitate antigen presentation and B-cell differentiation. The highly induced HIF1A and KLF6 protein expression in mast cells and macrophages sustain inflammation. Furthermore, immunogenomics discovered 24, 17, 6 and 11 significantly regulated marker genes to hallmark M1/M2 polarized macrophages, lymphocytic and granulocytic infiltrates; note, the latter was confirmed by CAE staining. Other highly regulated genes included alpha-2-macroglobulin, CRP, hepcidin, IL1R1, S100A8 and CCL20. Diclofenac treatment caused unprecedented induction of myeloperoxidase in macrophages and oxidative stress as shown by SOD1/SOD2 immunohistochemistry. Lastly, bioinformatics defined molecular circuits of inflammation and consisted of 161 regulated genes.

Altogether, the mechanism of diclofenac induced liver hypersensitivity reactions involved oxidative stress, macrophage polarization, mastocytosis, complement activation and an erroneous programming of the innate and adaptive immune system.

A genome-wide association study identifies six novel risk loci for primary biliary cholangitis

Primary biliary cholangitis (PBC) is an autoimmune liver disease with a strong hereditary component. Here, we report a genome-wide association study that included 1,122 PBC cases and 4,036 controls of Han Chinese descent, with subsequent replication in a separate cohort of 907 PBC cases and 2,127 controls. Our results show genome-wide association of 14 PBC risk loci including previously identified 6p21 (HLA-DRA and DPB1), 17q12 (ORMDL3), 3q13.33 (CD80), 2q32.3 (STAT1/STAT4), 3q25.33 (IL12A), 4q24 (NF-κB) and 22q13.1 (RPL3/SYNGR1). We also identified variants in IL21, IL21R, CD28/CTLA4/ICOS, CD58, ARID3A and IL16 as novel PBC risk loci. These new findings and histochemical studies showing enhanced expression of IL21 and IL21R in PBC livers (particularly in the hepatic portal tracks) support a disease mechanism in which the deregulation of the IL21 signalling pathway, in addition to CD4 T-cell activation and T-cell co-stimulation are critical components in the development of PBC.

The TNF family member TL1A induces IL-22 secretion in committed human Th17 cells via IL-9 induction

TL1A contributes to the pathogenesis of several chronic inflammatory diseases, including those of the bowel by enhancing TH1, TH17, and TH2 responses. TL1A mediates a strong costimulation of these TH subsets, particularly of mucosal CCR9+ T cells. However, the signaling pathways that TL1A induces in different TH subsets are incompletely understood. We investigated the function of TL1A on human TH17 cells. TL1A, together with TGF-β, IL-6, and IL-23, enhanced the secretion of IL-17 and IFN-γ from human CD4+ memory T cells. TL1A induced expression of the transcription factors BATF and T-bet that correlated with the secretion of IL-17 and IFN-γ. In contrast, TL1A alone induced high levels of IL-22 in memory CD4+ T cells and committed TH17 cells. However, TL1A did not enhance expression of IL-17A in TH17 cells. Expression of the transcription factor aryl hydrocarbon receptor, which regulates the expression of IL-22 was not affected by TL1A. Transcriptome analysis of TH17 cells revealed increased expression of IL-9 in response to TL1A. Blocking IL-9 receptor antibodies abrogated TL1A-induced IL-22 secretion. Furthermore, TL1A increased IL-9 production by peripheral TH17 cells isolated from patients with Crohn's disease. These data suggest that TL1A differentially induces expression of TH17 effector cytokines IL-17, -9, and -22 and provides a potential target for therapeutic intervention in TH17-driven chronic inflammatory diseases.

The influence of innate and adaptative immune responses on the differential clinical outcomes of leprosy

Leprosy is a chronic infectious disease caused by Mycobacterium leprae. According to official reports from 121 countries across five WHO regions, there were 213 899 newly diagnosed cases in 2014. Although leprosy affects the skin and peripheral nerves, it can present across a spectrum of clinical and histopathological forms that are strongly influenced by the immune response of the infected individuals. These forms comprise the extremes of tuberculoid leprosy (TT), with a M. leprae-specific Th1, but also a Th17, response that limits M. leprae multiplication, through to lepromatous leprosy (LL), with M. leprae-specific Th2 and T regulatory responses that do not control M. leprae replication but rather allow bacterial dissemination. The interpolar borderline clinical forms present with similar, but less extreme, immune biases. Acute inflammatory episodes, known as leprosy reactions, are complications that may occur before, during or after treatment, and cause further neurological damages that can cause irreversible chronic disabilities. This review discusses the innate and adaptive immune responses, and their interactions, that are known to affect pathogenesis and influence the clinical outcome of leprosy.

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.

DR3 signaling modulates the function of Foxp3+ regulatory T cells and the severity of acute graft-versus-host disease

CD4⁺Foxp3⁺ regulatory T cells (Treg) are a subpopulation of T cells, which regulate the immune system and enhance immune tolerance after transplantation. Donor-derived Treg prevent the development of lethal acute graft-versus-host disease (GVHD) in murine models of allogeneic hematopoietic stem cell transplantation. We recently demonstrated that a single treatment of the agonistic antibody to DR3 (death receptor 3, αDR3) to donor mice resulted in the expansion of donor-derived Treg and prevented acute GVHD, although the precise role of DR3 signaling in GVHD has not been elucidated. In this study, we comprehensively analyzed the immunophenotype of Treg after DR3 signal activation, demonstrating that DR3-activated Treg (DR3-Treg) had an activated/mature phenotype. Furthermore, the CD25⁺Foxp3⁺ subpopulation in DR3-Treg showed stronger suppressive effects in vivo. Prophylactic treatment of αDR3 to recipient mice expanded recipient-derived Treg and reduced the severity of GVHD, whereas DR3 activation in mice with ongoing GVHD further promoted donor T-cell activation/proliferation. These data suggest that the function of DR3 signaling was highly dependent on the activation status of the T cells. In conclusion, our data demonstrated that DR3 signaling affects the function of Treg and T-cell activation after alloantigen exposure in a time-dependent manner. These observations provide important information for future clinical testing using human DR3 signal modulation and highlight the critical effect of the state of T-cell activation on clinical outcomes after activation of DR3.

Expression and function of the TL1A/DR3 axis in chronic lymphocytic leukemia

TNF-like ligand 1A (TL1A) and its unique receptor death receptor 3 (DR3) acts as broad T-cell costimulator involved in regulatory mechanisms of adaptive immune response under physiological and pathological settings. Moreover, we have recently shown that TL1A negatively regulates B-cell proliferation. Despite increasing interest on the TL1A/DR3-axis functions, very little is known on its expression and role in leukemia. In this study, we investigated the expression and function of TL1A/DR3 axis in chronic lymphocytic leukemia (CLL). DR3 was differentially expressed in activated CLL cells and predominantly detected in patients with early clinical stage disease. Soluble TL1A has been revealed in the sera of CLL patients where higher TL1A levels were associated with early stage disease. T cells, monocytes and leukemic B cells have been identified as major sources of TL1A in CLL. The relevance of these findings has been sustained by functional data showing that exogenous TL1A reduces CLL proliferation induced by stimulation of the B cell receptor. Overall, these data document the expression of the TL1A/DR3 axis in early-stage CLL. They also identify a novel function for TL1A as a negative regulator of leukemic cell proliferation that may influence the CLL physiopathology and clinical outcome at an early-stage disease.

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.

New medical strategies for the management of acute diverticulitis

Acute diverticulitis, defined as acute inflammation of a colonic diverticulum, is a common emergency presentation managed by both surgeons and physicians. There have been advances in the medical treatments offered to patients in recent years. Factors predisposing individuals to the development of acute diverticulitis include obesity, smoking, lack of physical activity and medication use, such as NSAIDs. Although widely used, there is limited evidence on the efficacy of individual antibiotic regimens and antibiotic treatment may not be required in all patients. Mesalazine seems to be the only effective treatment for the primary prevention of acute diverticulitis. Finally, evidence of effective measures for the prevention of recurrence is lacking. Furthermore, high-quality randomized controlled trials are required for medical treatments in patients with acute diverticulitis, if management is to be evidence based.

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.