Rheumatoid arthritis-associated RBPJ polymorphism alters memory CD4+ T cells

The expression of RBPJ and its potential role in rheumatoid arthritis

BACKGROUND

Recombination signal-binding protein for immunoglobulin kappa J region (RBPJ) is a transcriptional regulator that plays an important role in maintaining immune homeostasis. This study aimed to estimate the expression of RBPJ in rheumatoid arthritis (RA) patients and investigate its relationship with RA.

METHODS

A total of 83 newly diagnosed RA patients and 70 healthy controls were included. mRNA was extracted from peripheral blood mononuclear cells (PBMCs), and the expression of RBPJ was detected using quantitative real-time PCR (qRT‒PCR). An RA dataset (GSE89408) was obtained from the Gene Expression Omnibus (GEO) database, and RA synovial tissues were divided into two groups. The differentially expressed genes (DEGs) were selected with the "DESeq2" R package.

RESULTS

RBPJ expression was lower in RA patients than in health controls and was negatively correlated with the DAS28 score, C-reactive protein (CRP) level and erythrocyte sedimentation rate (ESR). RA synovial tissues from GSE89408 were classified into RBPJ-low (≤ 25%) and RBPJ-high (≥ 75%) groups according to RBPJ expression, and 562 DEGs were identified. Gene Ontology (GO) enrichment analyses revealed that the DEGs significantly affected the regulation of T cell activation and lymphocyte/mononuclear cell differentiation. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis revealed that the most enriched pathways of DEGs were the T cell receptor signaling pathway, Th1/2 and Th17 cell differentiation, the PI3K - Akt signaling pathway and cytokine‒cytokine receptor interaction. CytoHubba Plugin revealed that most of the top 10 genes were involved in osteoclast differentiation, the T cell receptor signaling pathway and cytokine‒cytokine receptor interaction.

CONCLUSIONS

RBPJ expression was significantly lower in RA patients and negatively correlated with disease activity. GEO dataset analysis demonstrated that RBPJ may be involved in osteoclast differentiation, T cell activation and differentiation, and the T cell receptor signaling pathway. Our research may contribute to understanding the potential mechanisms by which RBPJ regulates T cell differentiation and cytokine‒cytokine receptor interaction in RA patients.

Notch ligands are biomarkers of anti-TNF response in RA patients

Notch and its ligands play a critical role in rheumatoid arthritis (RA) pathogenesis. Hence, studies were conducted to delineate the functional significance of the Notch pathway in RA synovial tissue (ST) cells and the influence of RA therapies on their expression. Morphological studies reveal that JAG1, DLL4, and Notch1 are highly enriched in RA ST lining and sublining CD68+CD14+ MΦs. JAG1 and DLL4 transcription is jointly upregulated in RA MΦs reprogrammed by TLR4/5 ligation and TNF, whereas Syntenin-1 exposure expands JAG1, DLL4, and Notch1 expression levels in these cells. Single-cell RNA-seq data exhibit that JAG1 and Notch3 are overexpressed on all fibroblast-like synoviocyte (FLS) subpopulations, in parallel, JAG2, DLL1, and Notch1 expression levels are modest on RA FLS and are predominately potentiated by TLR4 ligation. Intriguingly, JAG1, DLL1/4, and Notch1/3 are presented on RA endothelial cells, and their expression is mutually reconfigured by TLR4/5 ligation in the endothelium. Synovial JAG1/JAG2/DLL1 or Notch1/3 transcriptomes were unchanged in patients who received disease-modifying anti-rheumatic drugs (DMARDs) or IL-6R Ab therapy regardless of disease activity score. Uniquely, RA MΦs and endothelial cells rewired by IL-6 displayed DLL4 transcriptional upregulation, and IL-6R antibody treatment disrupted RA ST DLL4 transcription in good responders compared to non-responders or moderate responders. Nevertheless, the JAG1/JAG2/DLL1/DLL4 transcriptome was diminished in anti-TNF good responders with myeloid pathotype and was unaltered in the fibroid pathotype except for DLL4. Taken together, our findings suggest that RA myeloid Notch ligands can serve as markers for anti-TNF responsiveness and trans-activate Notch receptors expressed on RA FLS and/or endothelial cells.

Association of a Functional Single Nucleotide Polymorphism (rs874040) in the RBPJ Gene with Susceptibility to Rheumatoid Arthritis in Iranian Population

Background

Rheumatoid Arthritis (RA) is a progressive, heterogeneous, and common multifactorial autoimmune disease. Several Genome-Wide Association Studies (GWASs) have revealed more than 100 risk loci for RA. One of these loci is a functional single nucleotide polymorphism (rs874040; G>C) near the recombination signal-binding protein for the immunoglobulin kappa J region (RBPJ) gene. RBPJ can convert into a transcriptional activator upon activation of the canonical Notch pathway. Notch signaling has recently emerged as an important regulator of immune responses in inflammation and autoimmune diseases. In the present study, the possible association between SNP rs874040 (G>C) upstream of the RBPJ gene with RA risk was assessed in Iranian population.

Methods

A case-control study including 60 RA patients and 44 control subjects was conducted to estimate rs874040 genotypes using real-time polymerase chain reaction High Resolution Melting (HRM) method.

Results

Logistic regression analysis indicated that homozygous CC and heterozygous GC genotypes increase the risk of RA compared with GG genotype (CC vs. GG; OR=11.36; 95% CI [3.93-33.33] and CG vs. GG; OR=3.78; 95% CI [1.30-10. 98]). Besides, subjects with C allele were more frequently affected with RA than subjects with G allele (OR=10.42; 95% CI [5.21-20.83]). Furthermore, in the patient group, a significant correlation was found between C-reactive protein concentrations and rs874040 polymorphism (p<0.05).

Conclusion

Our findings propose a substantial correlation between rs874040 polymorphism and RA risk in Iranian population.

Antigen-reactive regulatory T cells can be expanded in vitro with monocytes and anti-CD28 and anti-CD154 antibodies

BACKGROUND

In recent years, therapies with CD4⁺CD25^highFoxP3⁺ regulatory T cells (Tregs) have been successfully tested in many clinical trials. The important issue regarding the use of this treatment in autoimmune conditions remains the specificity toward particular antigen, as because of epitope spread, there are usually multiple causative autoantigens to be regulated in such conditions.

METHODS

Here we show a method of generation of Tregs enriched with antigen-reactive clones that potentially covers the majority of such autoantigens. In our research, Tregs were expanded with anti-CD28 and anti-CD154 antibodies and autologous monocytes and loaded with a model peptide, such as whole insulin or insulin β chain peptide 9-23. The cells were then sorted into cells recognizing the presented antigen. The reactivity was verified with functional assays in which Tregs suppressed proliferation or interferon gamma production of autologous effector T cells (polyclonal and antigen-specific) used as responders challenged with the model peptide. Finally, we analyzed clonotype distribution and TRAV gene usage in the specific Tregs.

RESULTS

Altogether, the applied technique had a good yield and allowed us to obtain a Treg product enriched with a specific subset, as confirmed in the functional tests. The product consisted of many clones; nevertheless, the content of these clones was different from that found in polyclonal or unspecific Tregs.

CONCLUSIONS

The presented technique might be used to generate populations of Tregs enriched with cells reactive to any given peptide, which can be used as a cellular therapy medicinal product in antigen-targeted therapies.

Notch receptors and ligands in inflammatory arthritis - a systematic review

BACKGROUND

Notch pathway is highly conserved across species and is involved in the regulation of cell differentiation and activity both in embryonic development and adult life. Notch signaling has an important role in the development of hematopoietic stem cells and their differentiation to committed lineages, as well as in the regulation of several non-hematopoietic cell lines.

OBJECTIVE

As Notch signaling has been implicated in various inflammatory and autoimmune diseases, it is of interest to elucidate what role do Notch receptors and ligands have in inflammatory arthritides.

METHODS

We performed a search on the role of Notch receptors (1-4) and Notch ligands Delta-like (DLL) 1, 3, 4 and Jagged (Jag) 1 and 2 in animal models of inflammatory arthritis and most common types of human inflammatory arthritis (rheumatoid arthritis, psoriatic arthritis or ankylosing spondylitis). The initial search identified 135 unique articles, of which 24 were ultimately deemed relevant and included in this systematic review.

RESULTS

Overall, identified articles describe roles for Notch ligands and receptors in inflammatory arthritis, with Notch activation resulting in enhanced Th1/17 polarization, osteoclast differentiation, macrophage activation and fibroblast-like synoviocyte proliferation. However, the inhibitory role of Notch signaling, especially by Jag1 is also described.

CONCLUSION

There is evidence that Notch pathway activation affects multiple cell lineages present within the arthritic environment, therefore potentially acting as one of the drivers of disease pathogenesis. Since cell lineage-selective transgenic mouse models and specific Notch receptor inhibitors are becoming increasingly available, it can be expected that future research will evaluate whether Notch signaling components initiate crucial pathogenic impulses and, therefore, present viable therapeutic targets in inflammatory arthritis.

Abnormal expression and mutation of the RBPJ gene may be involved in CD59- clonal proliferation in paroxysmal nocturnal hemoglobinuria

Paroxysmal nocturnal hemoglobinuria (PNH) is an acquired clonal proliferative disease of hematopoietic stem cells. Various gene mutations, including the phosphatidylinositol glycan anchor biosynthesis class A (PIG-A) gene, may contribute to the proliferation of PNH clones. In order to explore the mechanism of PNH clone proliferation, a study was performed on 13 patients with PNH who underwent whole exome sequencing. The frequency of mutations in these patients was explored, and an additional 30 patients with PNH were selected for analysis of cluster of differentiation 59-negative (CD59^-) cells. The mRNA expression of 13 genes, which were selected based on their high frequency in patients with PNH and the fact that they met four screening conditions, was determined in these CD59^- cells. Cell proliferation, apoptosis and cell cycle were evaluated upon knocking down the recombinant signal binding protein of immunoglobulin κJ region (RBPJ) gene in 5 patients in vitro. The detection rate of PIG-A gene mutation was 61.54% (8/13), and additional mutations in somatic genes were detected, including RBPJ, zinc finger protein 717, polycomb repressive complex 2 subunit and tet methylcytosine dioxygenase. Upon screening according to the mutation frequency and expression level, the present study focused on the RBPJ gene. The expression level of RBPJ in CD59^- cells was apparently higher than that in CD59⁺ cells and normal controls which was significantly correlated with clinical data. Furthermore, the expression of RBPJ in PNH primary cells could be effectively inhibited by small interfering RNA-RBPJ. Once the expression of RBPJ decreased remarkably, the apoptotic rate increased gradually, while cell proliferation activity decreased with transfection time and cells were blocked in G0/G1 phase. In conclusion, mutations and abnormal expression of the RBPJ gene may participate in the abnormal proliferation of PNH clones.

RBPJ polymorphisms associated with cerebral infarction diseases in Chinese Han population: A Clinical Trial/Experimental Study (CONSORT Compliant)

TRIAL DESIGN

Cerebral small vessel diseases (CSVDs) are a group of brain pathological processes involving cerebral small arteries, brain venules, and capillaries. The recombination signal-binding protein Jκ (RBPJ) is implicated in the pathogenesis of these diseases but its actual roles need confirmation. The aim of this work was to evaluate variations in RBPJ gene for their possible associations with the disease.

METHODS

The RBPJ gene was sequenced for 400 patients with cerebral infarction disease and 600 normal controls. The statistical analyses and Hardy-Weinberg equilibrium tests of the patients and control populations were conducted using the SPSS software (version 19.0) and Plink (version 1.9), Haploview software, and online software SNPSpD.

RESULTS

We characterized variants rs2871198, rs1397731, rs3822223, rs2077777, rs2270226, and rs2788861 within or near the RBPJ gene. The genetic heterozygosity of rs2871198, rs1397731, rs3822223, rs2077777, and rs2270226 was very high. Statistical analysis showed that the variants rs2270226 and rs2077777 in the gene were associated with the risk of cerebral infarction diseases in the Chinese Han population.

CONCLUSIONS

rs2270226 and rs2077777 in the RBPJ gene were associated with the risk of cerebral infarction diseases in the Chinese Han population.

RBPJ mediates uterine repair in the mouse and is reduced in women with recurrent pregnancy loss

Unexplained recurrent pregnancy loss (uRPL) is associated with repeated embryo loss and endometrial repair with elevated endometrial expression of inflammatory cytokines, including IFN-γ. Notch signaling through its transcription factor recombination signal binding protein Jκ (RBPJ) regulates mechanisms including the immune response and repair after tissue injury. Initially, null mutation of RBPJ in the mouse uterus ( Pgr^cre/+Rbpj^f/f; Rbpj c-KO) results in subfertility, but we have found that these mice become infertile after pregnancy as a result of dysfunctional postpartum uterine repair, including delayed endometrial epithelial and myometrial regeneration. RNA sequencing of postpartum uterine repair sites revealed global up-regulation of inflammatory pathways, including IFN signaling. Consistent with elevated IFN-γ, macrophages were recruited and polarized toward an M1-cytotoxic phenotype, which is associated with preventing repair and promoting further tissue injury. Through embryo transfer experiments, we show that dysfunctional postpartum repair directly impairs future embryo implantation in Rbpj c-KO mice. Last, we clinically correlated our findings from the Rbpj c-KO mouse in women diagnosed with uRPL. Reduced RBPJ in women with uRPL was associated with increased levels of IFN-γ. The data, taken together, indicate that RBPJ regulates inflammation during endometrial repair, which is essential for future pregnancy potential, and its dysregulation may serve as an unidentified contributor to uRPL in women.-Strug, M. R., Su, R.-W., Kim, T. H., Mauriello, A., Ticconi, C., Lessey, B. A., Young, S. L., Lim, J. M., Jeong, J.-W., Fazleabas, A. T. RBPJ mediates uterine repair in the mouse and is reduced in women with recurrent pregnancy loss.

MS AHI1 genetic risk promotes IFNγ+ CD4+ T cells

Objective

To study the influence of the Abelson helper integration site 1 (AHI1) locus associated with MS susceptibility on CD4⁺ T cell function.

Methods

We characterized the chromatin state of T cells in the MS-associated AHI1 linkage disequilibrium (LD) block. The expression and the role of the AHI1 variant were examined in T cells from genotyped healthy subjects who were recruited from the PhenoGenetic Project, and the function of AHI1 was explored using T cells from Ahi1 knockout mice.

Results

Chromatin state analysis reveals that the LD block containing rs4896153, which is robustly associated with MS susceptibility (odds ratio 1.15, p = 1.65 × 10^-13), overlaps with strong enhancer regions that are present in human naive and memory CD4⁺ T cells. Relative to the rs4896153^A protective allele, the rs4896153^T susceptibility allele is associated with decreased AHI1 mRNA expression, specifically in naive CD4⁺ T cells (p = 1.73 × 10^-74, n = 213), and we replicate this effect in an independent set of subjects (p = 2.5 × 10^-9, n = 32). Functional studies then showed that the rs4896153^T risk variant and the subsequent decreased AHI1 expression were associated with reduced CD4⁺ T cell proliferation and a specific differentiation into interferon gamma (IFNγ)-positive T cells when compared with the protective rs4896153^A allele. This T cell phenotype was also observed in murine CD4⁺ T cells with genetic deletion of Ahi1.

Conclusions

Our findings suggest that the effect of the AHI1 genetic risk for MS is mediated, in part, by enhancing the development of proinflammatory IFNγ⁺ T cells that have previously been implicated in MS and its mouse models.