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T follicular helper (Tfh) cells are indispensable for the formation of germinal center (GC) reactions, whereas T follicular regulatory (Tfr) cells inhibit Tfh-mediated GC responses. Aberrant activation of Tfh cells contributes substantially to the pathogenesis of autoimmune diseases, such as systemic lupus erythematosus (SLE). Nonetheless, the molecular mechanisms mitigating excessive Tfh cell differentiation are not fully understood. Herein we demonstrate that the adenovirus E4 promoter-binding protein (E4BP4) mediates a feedback loop and acts as a transcriptional brake to inhibit Tfh cell differentiation. Furthermore, we show that such an immunological mechanism is compromised in patients with SLE. Establishing mice with either conditional knockout (cKO) or knockin (cKI) of the E4bp4 gene in T cells reveals that E4BP4 strongly inhibits Tfh cell differentiation. Mechanistically, E4BP4 regulates Bcl6 transcription by recruiting the repressive epigenetic modifiers HDAC1 and EZH2. E4BP4 phosphorylation site mutants have limited capability with regard to inhibiting Tfh cell differentiation. In SLE, we detected impaired phosphorylation of E4BP4, finding that this compromised transcription factor is positively correlated with disease activity. These findings unveiled molecular mechanisms by which E4BP4 restrains Tfh cell differentiation, whose compromised function is associated with uncontrolled autoimmune reactions in SLE. [ABSTRACT FROM AUTHOR]

Background and Aims: Combining anti-angiogenic therapy with immune checkpoint blockade with anti-programmed cell death-1 (PD-1) antibodies is a promising treatment for hepatocellular carcinoma (HCC). Tyrosine kinase inhibitors are well-known anti-angiogenic agents and offer potential for combination with anti-PD-1 antibodies. This study investigated the possible underlying immunomodulatory mechanisms of combined therapy. Methods: HCC tissue samples for RNA-sequencing (RNA-seq) were obtained from patients with differential prognoses following anti-PD-1 treatment. Recombinant basic fibroblast growth factor (bFGF) and vascular endothelial growth factor A (VEGFA) were used to stimulate T cells following lenvatinib or sorafenib treatment, respectively. T cell function was analyzed by flow cytometry and lactate dehydrogenase assay. In vivo experiments were conducted in murine H22 and Hepa 1-6 competent models of HCC. Local immune infiltration in the tumor microenvironment (TME) was assessed using multicolor flow cytometry. Gene regulation was evaluated by RNA-seq. Microvascular density was measured by immunohistochemistry, and PD-1 ligand (PD-L1) induction was quantified by western blot. Results: The baseline expression of VEGF and fibroblast growth factor (FGF) in patients with progressive disease was significantly higher than in patients achieving stable disease following anti-PD-1 treatment. VEGFA and bFGF significantly upregulated the expression of PD-1, cytotoxic T-lymphocyte-associated protein- 4, and Tim-3 on T cells, while inhibiting the secretion of interferon gamma (IFNG) and granzyme B and suppressing T cell cytotoxicity. This immunosuppressive effect was reverted by lenvatinib but not sorafenib. Furthermore, dual lenvatinib/anti-PD-1 antibody therapy led to better antitumor effects than either sorafenib or fibroblast growth factor receptor (FGFR) inhibitor (BGJ398) in H22 murine models of HCC. Combined lenvatinib/anti-PD-1 treatment also led to long-term immune memory formation, while synergistically modulating the TME and enhancing the cytotoxic effect of T cells. Finally, lenvatinib inhibited PD-L1 expression on human umbilical vein endothelial cells, which improved the function of T cells. Conclusions: Inhibition of vascular endothelial growth factor receptor and FGFR augmented the efficacy of anti-PD-1 antibodies. Combined lenvatinib/anti-PD-1 treatment appears to exert antitumor activity by synergistically modulating effector T cell function in the TME and by mutually regulating tumor vessel normalization. [ABSTRACT FROM AUTHOR]

Objective: T cell receptor (TCR) diversity determines the autoimmune responses in systemic lupus erythematosus (SLE) and rheumatoid arthritis (RA) and is closely associated with autoimmune diseases prognosis and prevention. However, the characteristics of variations in TCR diversity and their clinical significance is still unknown. Large series of patients must be studied in order to elucidate the effects of these variations.Methods: Peripheral blood from 877 SLE patients, 206 RA patients and 439 healthy controls (HC) were amplified for the TCR repertoire and sequenced using a high-throughput sequencer. We have developed a statistical model to identify disease-associated TCR clones and diagnose autoimmune diseases.Results: Significant differences were identified in variable (V), joining (J) and V-J pairing between the SLE or RA and HC groups. These differences can be utilised to discriminate the three groups with perfect accuracy (V: area under receiver operating curve > 0.99). One hundred ninety-eight SLE-associated and 53 RA-associated TCRs were identified and used for diseases classification by cross validation with high specificity and sensitivity. Disease-associated clones showed common features and high similarity between both autoimmune diseases. SLE displayed higher TCR heterogeneity than RA with several organ specific properties. Furthermore, the association between clonal expansion and the concentration of disease-associated clones with disease severity were identified, and pathogen-related TCRs were enriched in both diseases.Conclusions: These characteristics of the TCR repertoire, particularly the disease-associated clones, can potentially serve as biomarkers and provide novel insights for disease status and therapeutical targets in autoimmune diseases. [ABSTRACT FROM AUTHOR]

Epigenetic modifications affect the differentiation of T cell subsets and the pathogenesis of autoimmune diseases, but many mechanisms of epigenetic regulation of T cell differentiation are unclear. Here we show reduced expression of the transcription factor RFX1 in CD4+ T cells from patients with systemic lupus erythematosus, which leads to IL-17A overexpression through increased histone H3 acetylation and decreased DNA methylation and H3K9 tri-methylation. Conditional deletion of Rfx1 in mice exacerbates experimental autoimmune encephalomyelitis and pristane-induced lupus-like syndrome and increases induction of Th17 cells. In vitro, Rfx1 deficiency increases the differentiation of naive CD4+ T cells into Th17 cells, but this effect can be reversed by forced expression of Rfx1. Importantly, RFX1 functions downstream of STAT3 and phosphorylated STAT3 can inhibit RFX1 expression, highlighting a non-canonical pathway that regulates differentiation of Th17 cells. Collectively, our findings identify a unique role for RFX1 in Th17-related autoimmune diseases. [ABSTRACT FROM AUTHOR]

Systemic lupus erythematosus (SLE) is an autoimmune disease involving multiple organs and the presence of anti-nuclear antibodies. The pathogenesis of SLE has been intensively studied but remains far from clear. B and T lymphocyte abnormalities, dysregulation of apoptosis, defects in the clearance of apoptotic materials, and various genetic and epigenetic factors are attributed to the development of SLE. The latest research findings point to the association between abnormal epigenetic regulation and SLE, which has attracted considerable interest worldwide. It is the purpose of this review to present and discuss the relationship between aberrant epigenetic regulation and SLE, including DNA methylation, histone modifications and microRNAs in patients with SLE, the possible mechanisms of immune dysfunction caused by epigenetic changes, and to better understand the roles of aberrant epigenetic regulation in the initiation and development of SLE and to provide an insight into the related therapeutic options in SLE. [ABSTRACT FROM AUTHOR]

Treatment for cancer can induce a series of secreted factors into the tumor microenvironment, which can affect cancer progression. Wingless-type MMTV (mouse mammary tumor virus) integration site 16B (WNT16B) is a new member of the WNT family and has been reported to play growth-related roles in previous studies. In this study, we found WNT16B could be expressed and secreted into the microenvironment by human ovarian fibroblasts after DNA damage-associated treatment, including chemotherapy drugs and radiation. We also demonstrated that fibroblast-derived WNT16B could result in accumulation of ß-catenin in dendritic cells and secretion of interleukin-10 (IL-10) and transforming growth factor beta (TGF-ß), which contributed to the differentiation of regulatory T cells in a co-culture environment. These results shed light on the roles of WNT16B in immune regulation, especially in regard to cancer treatment. [ABSTRACT FROM AUTHOR]

Background: Adoptive transfer of chimeric antigen receptor (CAR)-modified T cells appears to be a promising immunotherapeutic strategy. CAR combines the specificity of antibody and cytotoxicity of cytotoxic T lymphocytes, enhancing T cells' ability to specifically target antigens and to effectively kill cancer cells. Recent efforts have been made to integrate the costimulatory signals in the CAR to improve the antitumor efficacy. Epidermal growth factor receptor variant III (EGFRvIII) is an attractive therapeutic target as it frequently expresses in glioma and many other types of cancers. Our current study aimed to investigate the specific and efficient antitumor effect of T cells modified with CAR containing inducible costimulator (ICOS) signaling domain. Methods: A second generation of EGFRvIII/CAR was generated and it contained the EGFRvIII single chain variable fragment, ICOS signaling domain and CD3ζ chain. Lentiviral EGFRvIII/CAR was prepared and human CD3+ T cells were infected by lentivirus encoding EGFRvIII/CAR. The expression of EGFRvIII/CAR on CD3+ T cells was confirmed by flow cytometry and Western blot. The functions of EGFRvIII/CAR+ T cells were evaluated using in vitro and in vivo methods including cytotoxicity assay, cytokine release assay and xenograft tumor mouse model. Results: Chimeric EGFRvIIIscFv-ICOS-CD3ζ (EGFRvIII/CAR) was constructed and lentiviral EGFRvIII/CAR were made to titer of 106 TU/ml. The transduction efficiency of lentiviral EGFRvIII/CAR on T cells reached around 70% and expression of EGFRvIII/CAR protein was verified by immunoblotting as a band of about 57 kDa. Four hour 51Cr release assays demonstrated specific and efficient cytotoxicity of EGFRvIII/CAR+ T cells against EGFRvIII expressing U87 cells. A robust increase in the IFN-γ secretion was detected in the co-culture supernatant of the EGFRvIII/CAR+ T cells and the EGFRvIII expressing U87 cells. Intravenous and intratumor injection of EGFRvIII/CAR+ T cells inhibited the in vivo growth of the EGFRvIII expressing glioma cells. Conclusions: Our study demonstrates that the EGFRvIII/CAR-modified T cells can destroy glioma cells efficiently in an EGFRvIII specific manner and release IFN-γ? in an antigen dependent manner. The specific recognition and effective killing activity of the EGFRvIII-directed T cells with ICOS signaling domain lays a foundation for us to employ such approach in future cancer treatment. [ABSTRACT FROM AUTHOR]

The article presents a study which examines if the gadd45A gene can add to autoimmunity through the progress of DNA demethylation in T cells from patients with systemic lupus erythematosus (SLE). The study detects the level of GADD45α, CD70 and CD111a messenger RNA (mRNA) and protein with the use of real-time reverse transcription-polymerase chain reaction. Results show that global DNA hypomethylation and advanced gadd45A mRNA expression were discovered in CD4+ T cells from SLE patients.

Interleukin- (IL-)10 and IL-13 play important roles in Th2 cell differentiation and production of autoantibodies in patients with (SLE). However, the mechanisms leading to IL10 and IL13 overexpression in SLE patients are not well understood. In this study, we confirm that the levels of both IL10 and IL13 mRNA in CD4+ T cells and of serum IL10 and IL13 proteins are increased in SLE patients. We show that the DNA methylation levels within IL10 and IL13 gene regulatory domains are reduced in SLE CD4+ T cells relative to healthy controls and negatively correlate with IL10 and IL13 mRNA expression. Moreover, treating healthy CD4+ T cells with the demethylating agent 5-azacytidine (5-azaC) increased IL10 and IL13 mRNA transcription. Together, our results show that promoter methylation is a determinant of IL10 and IL13 expression in CD4+ T cells, and we propose that DNA hypomethylation leads to IL10 and IL13 overexpression in SLE patients. [ABSTRACT FROM AUTHOR]

Calcineurin (CN), a Ca2+/calmodulin-regulated phophatase 2B, plays an important role in many biological processes including T-cell signal transduction. In the present study, the distribution and activity of CN were investigated in rat tissues. CN has a wide tissue distribution, as measured by enzyme-linked immunosorbent assay. CN concentrations are 0.2–0.6 μg/mg protein in most tissues, while the brain contains 3–10-fold higher concentrations. lmmunohistochemical analyses using a monoclonal antibody to CN B subunit reveals that CN is not evenly distributed but concentrated in specific cells, especially in the brain, kidneys and testis. The specific enzymic activity of CN in tissues is around 10 pmol · min · mg protein-1, except in brain and liver (60 pmol · min-1 · mg protein-1 compared to 3.6 pmol · min-1 · mg protein-1). The immunosuppressants cyclosporin A and tacrolimus, but not rapamycin, inhibit the phosphatase activity of CN derived from most tissues tested, while CN activity from liver was resistant to cyclosporin A. Furthermore, transcripts and protein of the common CN B subunit and of the testis-specific form of CN B subunit were analyzed. The common CN B subunit transcripts and protein are detected in all tissues. Transcripts for the ‘testis-specific’ CN B subunit are also found in brain, lung, thymus and heart, while the protein is only detected in testis. This indicates that the testis-specific CN B subunit gene expression is regulated at both transcriptional and posttranscriptional levels. The findings demonstrate that CN is a widely distributed protein phosphatase and that its activity is regulated in a tissue-specific manner. [ABSTRACT FROM AUTHOR]

The article discusses the abnormal expression pattern of histone demethylases in CD4+ T cells of MRL/lpr lupus-like mice. It examines the etiopathogenesis of systemic lupus erythematosus (SLE) in a chronic, recurrent, and potentially deadly autoimmune disease. It notes that the data provided require more evidence that histone methylation status in CD4+ T cells is altered in patients with lupus diseases.

The trace element iron affects immune responses and vaccination, but knowledge of its role in autoimmune diseases is limited. Expansion of pathogenic T cells, especially T follicular helper (Tfh) cells, has great significance to systemic lupus erythematosus (SLE) pathogenesis. Here, we show an important role of iron in regulation of pathogenic T cell differentiation in SLE. We found that iron overload promoted Tfh cell expansion, proinflammatory cytokine secretion, and autoantibody production in lupus-prone mice. Mice treated with a high-iron diet exhibited an increased proportion of Tfh cell and antigen-specific GC response. Iron supplementation contributed to Tfh cell differentiation. In contrast, iron chelation inhibited Tfh cell differentiation. We demonstrated that the miR-21/BDH2 axis drove iron accumulation during Tfh cell differentiation and further promoted Fe2+-dependent TET enzyme activity and BCL6 gene demethylation. Thus, maintaining iron homeostasis might be critical for eliminating pathogenic Th cells and might help improve the management of patients with SLE. [ABSTRACT FROM AUTHOR]

In LADA patients, Tregs are reduced and FOXP3 is downregulated in CD4 + T cells, but the etiology remains unclear. Our study included in 20 LADA patients and 20 healthy control patients. qRT-PCR results showed that STAT3, HDAC3, HDAC5, SIRT1, DNMT1 and DNMT3b mRNAs were significantly upregulated in LADA CD4 + T cells than controls, while FOXP3 mRNA significantly decreased. p-STAT3, STAT3, DNMT1 and DNMT3b expressions were increased demonstrated by western blot. ChIP-PCR suggested that p-STAT3 binds to the Foxp3 promoter, meanwhile, histone H3 acetylation at K9 and K14 of FOXP3 promoter were significantly lower than controls. Luciferase reporter assay showed that ectopic STAT3 expression significantly reduced FOXP3 promoter activities. The Foxp3 promoter was significantly hypermethylated in LADA than controls. LADA patients showed stronger binding of p-STAT3, HDAC5 and DNMT1 than controls using CHIP. These findings reveal a crucial role of STAT3 in regulating the epigenetic status of T cells in LADA. [ABSTRACT FROM AUTHOR]

Immune imbalance of T lymphocyte subsets is a hallmark of psoriasis, but the molecular mechanisms underlying this aspect of psoriasis pathology are poorly understood. Here, we report that microRNA-210 (miR-210), a miR that is highly expressed in both psoriasis patients and mouse models, induces helper T (Th) 17 and Th1 cell differentiation but inhibits Th2 differentiation through repressing STAT6 and LYN expression, contributing to several aspects of the immune imbalance in psoriasis. Both miR-210 ablation in mice and inhibition of miR-210 by intradermal injection of antagomir-210 blocked the immune imbalance and the development of psoriasis-like inflammation in an imiquimod-induced or IL-23-induced psoriasis-like mouse model. We further showed that TGF-β and IL-23 enhance miR-210 expression by inducing HIF-1α, which recruits P300 and promotes histone H3 acetylation in the miR-210 promoter region. Our results reveal a crucial role for miR-210 in the immune imbalance of T lymphocyte subsets in psoriasis and suggest a potential therapeutic avenue. [ABSTRACT FROM AUTHOR]