IL1R8 Deficiency Drives Autoimmunity-Associated Lymphoma Development

TIR8 protects against nonalcoholic steatohepatitis by antagonizing lipotoxicity-induced PPARα downregulation and reducing the sensitivity of hepatocytes to LPS

In up to one-third of nonalcoholic fatty liver disease (NAFLD) patients, simple steatosis progresses to its more severe form, nonalcoholic steatohepatitis (NASH), but the precise mechanisms underlying this transition are not fully understood. Toll/interleukin-1 receptor 8 (TIR8), a conventional innate immune regulator highly expressed in hepatic tissue, has shown potential for ameliorating various inflammation-related disorders. However, its role in NASH pathogenesis, especially its regulatory effects on lipid metabolism and inflammatory responses, is still unclear. Here, using a TIR8 knockout (TIR8KO) mouse model and mass spectrometry analyses, we found that TIR8KO mice displayed aggravated hepatic steatosis and inflammation, whereas TIR8 overexpression attenuated these adverse effects. Ectopic TIR8 expression counteracts free fatty acid (FFA)-induced PPARα inhibition and downstream signaling. A decrease in TIR8 levels in hepatocytes heightened lipopolysaccharide (LPS) sensitivity. Notably, FFA stimulation led to a direct interaction between TIR8 and proteasome subunit alpha type 4 (PSMA4), facilitating TIR8 degradation. These results revealed that TIR8 safeguards PPARα-regulated lipid metabolism and mitigates inflammation induced by external factors during NASH progression. Our study highlights TIR8 as a promising target for NASH therapy, indicating the potential of TIR8 agonists in treatment strategies.

IL-1R8 expression in DLBCL regulates NK cell recruitment and influences patient prognosis

The precise biological function of Interleukin-1 receptor 8 (IL-1R8) in diffuse large B-cell lymphoma (DLBCL) is still not well understood. Our goal is to decipher the profile of IL-1R8 expression status in DLBCL and to explore how IL-1R8 is involved in DLBCL progression. Utilizing a tissue microarray consisting of 70 samples of DLBCL tumors alongside 15 samples of tonsillitis, our investigation revealed a parallel expression profile of IL-1R8 between the tumor tissues and tonsillitis samples (p > 0.05). Nevertheless, an intriguing association emerged, as heightened expression of IL-1R8 correlated significantly with unfavorable survival outcomes in patients with DLBCL (p < 0.05). The status of IL-1R8 expression did not directly regulate proliferation (p > 0.05) and apoptosis (p > 0.05) in DLBCL cells via CCK8 and apoptotic assays. Subsequent chemotaxis analysis indicated that natural killer (NK) cell recruitment could be suppressed by IL-1R8 signaling in DLBCL, at least partially through CXCL1 inhibition (p < 0.05). The status of IL-1R8 expression in tumor tissues exhibited a negative correlation with the density of CD57+ NK cell infiltration (p < 0.05), while it did not demonstrate a significant association with CD3+ T cells (p > 0.05), CD68+ macrophages (p > 0.05), or S-100+ dendritic cells (p > 0.05). In line with this observation, elevated levels of NK cell infiltration demonstrated a significant positive correlation with improved overall survival (OS) among patients diagnosed with DLBCL (p < 0.05). Our data suggests the immuno-regulating potential of IL-1R8 through NK cell recruitment in DLBCL, providing novel insights into future immuno-modulating therapies.

The causal effect of inflammatory bowel disease on diffuse large B-cell lymphoma: two-sample Mendelian randomization study

Background

It has been reported that inflammatory bowel disease (IBD) is associated with an increased risk of malignancies, including lymphoma. A number of large observational studies have been devoted to exploring the causal link between IBD and malignant lymphoma. However, no consensus exists on whether there is a causal relationship between IBD and malignant lymphoma.

Methods

The summary dataset of the IBD and lymphoma genome-wide association studies (GWAS) was obtained from the OPEN GWAS website. Single-nucleotide polymorphisms (SNPs) were selected as genetic instrumental variants (IVs) for fulling P < 5 × 10-8 and linkage disequilibrium (LD) of r2 = 0.001 in the IBD GWAS. The proxy SNPs with LD of r2 > 0.8 were identified. Palindromic SNPs and outlier SNPs were excluded. The assessments of sensitivity employed the Cochran's Q test, Mendelian randomization (MR)-Egger intercept test, and leave-one-out analysis.

Results

The MR analysis results proved the causality of IBD on diffuse large B-cell lymphoma (DLBCL). The risk of developing DLBCL is increased by 28.6% in patients with IBD [odds ratio (OR)IVW = 1.286, 95% confidence interval (CI) 1.066-1.552, P = 0.009]. The results of the subgroup analysis showed that Crohn's disease (ORIVW = 1.218, 95% CI 1.030-1.441, P = 0.021) rather than ulcerative colitis (ORIVW = 1.206, 95% CI 0.984-1.478, P = 0.072) had a causal effect on DLBCL. No horizontal and directional pleiotropy was observed in the MR studies.

Conclusions

The above MR study concluded that IBD itself is causally responsible for DLBCL, especially Crohn's disease. Further investigations are needed to elucidate the mechanism underlying this direct causal link.

Chronic Epstein-Barr virus infection: A potential junction between primary Sjögren's syndrome and lymphoma

Primary Sjögren's syndrome (pSS) is an autoimmune disease that targets exocrine glands, leading to exocrine dysfunction. Due to its propensity to infect epithelial and B cells, Epstein-Barr virus (EBV) is hypothesized to be related with pSS. Through molecular mimicry, the synthesis of specific antigens, and the release of inflammatory cytokines, EBV contributes to the development of pSS. Lymphoma is the most lethal outcome of EBV infection and the development of pSS. As a population-wide virus, EBV has had a significant role in the development of lymphoma in people with pSS. In the review, we will discuss the possible causes of the disease.

IL-1R8: A molecular brake of anti-tumor and anti-viral activity of NK cells and ILC

Interleukin-1 receptor family members (ILRs) and Toll-Like Receptors (TLRs) play pivotal role in immunity and inflammation and are expressed by most cell types including cells of both the innate and adaptive immune system. In this context, IL-1 superfamily members are also important players in regulating function and differentiation of adaptive and innate lymphoid cells. This system is tightly regulated in order to avoid uncontrolled activation, which may lead to detrimental inflammation contributing to autoimmune or allergic responses. IL-1R8 (also known as TIR8 or SIGIRR) is a member of the IL-1R family that acts as a negative regulator dampening ILR and TLR signaling and as a co-receptor for human IL-37. Human and mouse NK cells, that are key players in immune surveillance of tumors and infections, express high level of IL-1R8. In this review, we will summarize our current understanding on the structure, expression and function of IL-1R8 and we will also discuss the emerging role of IL-1R8 as an important checkpoint regulating NK cells function in pathological conditions including cancer and viral infections.

SIGIRR deficiency contributes to CD4 T cell abnormalities by facilitating the IL1/C/EBPβ/TNF-α signaling axis in rheumatoid arthritis

Background

Rheumatoid arthritis (RA) is a complex autoimmune disease with multiple etiological factors, among which aberrant memory CD4 T cells activation plays a key role in the initiation and perpetuation of the disease. SIGIRR (single immunoglobulin IL-1R-related receptor), a member of the IL-1 receptor (ILR) family, acts as a negative regulator of ILR and Toll-like receptor (TLR) downstream signaling pathways and inflammation. The aim of this study was to investigate the potential roles of SIGIRR on memory CD4 T cells in RA and the underlying cellular and molecular mechanisms.

Methods

Single-cell transcriptomics and bulk RNA sequencing data were integrated to predict SIGIRR gene distribution on different immune cell types of human PBMCs. Flow cytometry was employed to determine the differential expression of SIGIRR on memory CD4 T cells between the healthy and RA cohorts. A Spearman correlation study was used to determine the relationship between the percentage of SIGIRR+ memory CD4 T cells and RA disease activity. An AIA mouse model (antigen-induced arthritis) and CD4 T cells transfer experiments were performed to investigate the effect of SIGIRR deficiency on the development of arthritis in vivo. Overexpression of SIGIRR in memory CD4 T cells derived from human PBMCs or mouse spleens was utilized to confirm the roles of SIGIRR in the intracellular cytokine production of memory CD4 T cells. Immunoblots and RNA interference were employed to understand the molecular mechanism by which SIGIRR regulates TNF-α production in CD4 T cells.

Results

SIGIRR was preferentially distributed by human memory CD4 T cells, as revealed by single-cell RNA sequencing. SIGIRR expression was substantially reduced in RA patient-derived memory CD4 T cells, which was inversely associated with RA disease activity and related to enhanced TNF-α production. SIGIRR-deficient mice were more susceptible to antigen-induced arthritis (AIA), which was attributed to unleashed TNF-α production in memory CD4 T cells, confirmed by decreased TNF-α production resulting from ectopic expression of SIGIRR. Mechanistically, SIGIRR regulates the IL-1/C/EBPβ/TNF-α signaling axis, as established by experimental evidence and cis-acting factor bioinformatics analysis.

Conclusion

Taken together, SIGIRR deficiency in memory CD4 T cells in RA raises the possibility that receptor induction can target key abnormalities in T cells and represents a potentially novel strategy for immunomodulatory therapy.

Genetic and epigenetic alterations of cyclic AMP response element modulator in rheumatoid arthritis

BACKGROUND

Genetic and epigenetic factors are strongly associated with the autoimmune disease rheumatoid arthritis (RA). Cyclic AMP response element modulator (CREM), a gene related to immune system regulation, has been implicated in various immune-mediated inflammatory processes, although it remains unknown whether CREM is involved in RA.

METHODS

This study enrolled 278 RA patients and 262 controls. Three variants [rs12765063, rs17499247, rs1213386] were identified through linkage disequilibrium and expression quantitative trait locus analysis, and CREM transcript abundance was determined by quantitative real-time polymerase chain reaction. The identified variants were genotyped using the TaqMan Allelic Discrimination assay, and CREM promoter methylation was assessed by bisulphite sequencing. Differences between groups and correlations between variables were assessed with Student's t-tests and Pearson's correlation coefficients. Associations between phenotypes and genotypes were evaluated with logistic regression.

RESULTS

Rheumatoid arthritis patients exhibited increased CREM expression (p < .0001), which was decreased by methotrexate (p = .0223) and biologics (p = .0001), but could not be attributed to CREM variants. Interestingly, rs17499247 displayed a significant association with serositis (p = .0377), and rs1213386 increased the risk of lymphadenopathy (p = .0398). Furthermore, seven CpG sites showed decreased methylation in RA (p = .0477~ p < .0001).

CONCLUSIONS

Collectively, our results indicate that CREM hypomethylation and CREM upregulation occur in RA and that CREM variants are involved in the development of serositis and lymphadenopathy in RA. This study highlights the novel roles of CREM in RA pathophysiology.

IL-1R8 Downregulation and Concomitant TLR7 and TLR9 Upregulation Are Related to the Pathogenesis of Canine Diffuse Large B-Cell Lymphoma

Diffuse large B-cell lymphoma (DLBCL) is the most common hematological malignancy in humans and dogs. Several studies disclosed some similarities between the two species, including the constitutive activation of the NF-κB pathway as a fundamental underlying pathogenetic mechanism. In humans, the downregulation of IL-1R8 is implicated in DLBCL development, but its role in dogs has not been explored so far. To gain insight into the pathogenesis of this tumor in dogs, we evaluated the mRNA and protein expression of IL-1R8 in 12 control lymph nodes obtained from dogs not bearing tumors and from 50 dogs with DLBCL. Moreover, we analyzed through qRT-PCR the expression of TLR7, TLR9, MYC, and p52 genes that are known to be involved in the IL-1R8 regulatory network. IL-1R8 and p52 were downregulated in DLBCLs compared to control lymph nodes (p < 0.001), while a higher expression of TLR7, TLR9, and MYC was observed in DLBCLs (p < 0.01). Immunohistochemistry confirmed the gene expression results, revealing a significantly lower IL-1R8 staining score in DLBCLs compared to control lymph nodes (p < 0.0001). Taken together, these results suggest that IL-1R8 downregulation may represent one of the mechanisms driving DLBCL pathogenesis in dogs, mainly through the dysregulation of the Toll-like/interleukin receptors signaling cascade and the aberrant activation of the classical NF-κB pathway.

Negative Regulation of the IL-1 System by IL-1R2 and IL-1R8: Relevance in Pathophysiology and Disease

Interleukin-1 (IL-1) is a primary cytokine of innate immunity and inflammation. IL-1 belongs to a complex family including ligands with agonist activity, receptor antagonists, and an anti-inflammatory cytokine. The receptors for these ligands, the IL-1 Receptor (IL-1R) family, include signaling receptor complexes, decoy receptors, and negative regulators. Agonists and regulatory molecules co-evolved, suggesting the evolutionary relevance of a tight control of inflammatory responses, which ensures a balance between amplification of innate immunity and uncontrolled inflammation. IL-1 family members interact with innate immunity cells promoting innate immunity, as well as with innate and adaptive lymphoid cells, contributing to their differentiation and functional polarization and plasticity. Here we will review the properties of two key regulatory receptors of the IL-1 system, IL-1R2, the first decoy receptor identified, and IL-1R8, a pleiotropic regulator of different IL-1 family members and co-receptor for IL-37, the anti-inflammatory member of the IL-1 family. Their complex impact in pathology, ranging from infections and inflammatory responses, to cancer and neurologic disorders, as well as clinical implications and potential therapeutic exploitation will be presented.

Cellular and gene signatures of tumor-infiltrating dendritic cells and natural-killer cells predict prognosis of neuroblastoma

Tumor-infiltrating lymphocytes play an essential role in improving clinical outcome of neuroblastoma (NB) patients, but their relationship with other tumor-infiltrating immune cells in the T cell-inflamed tumors remains poorly investigated. Here we show that dendritic cells (DCs) and natural killer (NK) cells are positively correlated with T-cell infiltration in human NB, both at transcriptional and protein levels, and associate with a favorable prognosis. Multiplex imaging displays DC/NK/T cell conjugates in the tumor microenvironment of low-risk NB. Remarkably, this connection is further strengthened by the identification of gene signatures related to DCs and NK cells able to predict survival of NB patients and strongly correlate with the expression of PD-1 and PD-L1. In summary, our findings unveil a key prognostic role of DCs and NK cells and indicate their related gene signatures as promising tools for the identification of clinical biomarkers to better define risk stratification and survival of NB patients.

Tumour-infiltrating lymphocytes play a crucial role in neuroblastoma, but their relationship to other immune cells is poorly understood. Here the authors identify the cellular and gene signatures of intratumoural dendritic cells and natural killer cells that predict the clinical outcome of neuroblastoma.

Genetic contributors and soluble mediators in prediction of autoimmune comorbidity

Comorbidities including subclinical atherosclerosis, neuropsychological aberrations and lymphoproliferation represent a major burden among patients with systemic autoimmune diseases; they occur either as a result of intrinsic disease related characteristics including therapeutic interventions or traditional risk factors similar to those observed in general population. Soluble molecules recently shown to contribute to subclinical atherosclerosis in the context of systemic lupus erythematosus (SLE) include among others B-cell activating factor (BAFF), hyperhomocysteinemia, parathormone (PTH) levels and autoantibodies against oxidized lipids. Variations of the 5, 10- methylenetetrahydrofolate reductase (MTHFR) gene -the main genetic determinant of hyperhomocystenemia in humans-as well the interferon regulatory factor-8 (IRF8), FcγRIIA and BAFF genes have been all linked to subclinical atherosclerosis in SLE. BAFF variants have been also found to confer increased risk for subclinical atherosclerosis and lymphoma development in Sjogren's syndrome (SS) patients. Other genes shown to be implicated in SS lymphoproliferation include genes involved a. in inflammatory responses such as the NFκB regulator Tumor necrosis factor alpha-induced protein 3 (TNFAIP3) and the Leukocyte immunoglobulin-like receptor A3 (LILRA3) immunoreceptor, b. B cell activation and signaling (BAFF/BAFF-receptor), c. type I IFN pathway such as three-prime repair exonuclease 1 (TREX1), d. epigenetic processes including DNA methylation (MTHFR rs1801133, 677T allele) and e. genomic instability (MTHFR rs1801131, 1298C allele). Emerging soluble biomarkers for SS related lymphoma include mediators of B cell growth and germinal center formation such as BAFF, FMS-like tyrosine kinase 3 ligand (Flt-3L) and CXCL13 as well as inflammatory contributors such as inteleukin (IL)-17, IL-18, ASC, LILRA3 and the extracellular lipoprotein-associated phospholipase A2 (Lp-PLA2). In regard to fatigue and neuropsychologic features in the setting of SS, contributing factors such as BAFF variants, antibodies against neuropeptides, proteins involved in nervous system function as well as inflammatory cytokines have been reported.