T-box proteins differentially activate the expression of the endogenous interferon γ gene versus transfected reporter genes in non-immune cells

T-box transcription factor 2 mediates antitumor immune response in cutaneous squamous cell carcinoma by regulating the expression of programmed death ligand 1

BACKGROUND

Cutaneous squamous cell carcinoma (CSCC) is the second largest nonmelanoma skin cancer in humans; effective treatment options for metastatic CSCC are still in short. In this study, we aimed to explore the function of T-box transcription factor 2 (TBX2) in CSCC.

METHODS

The expression level of TBX2 was determined in CSCC samples and cell lines. Programmed death ligand 1 (PD-L1) expression was also analyzed in human CSCC samples. Furthermore, SCC13 cells were transfected with TBX2-DN (loss of function) or normal TBX2 to check its role in regulating PD-L1.

RESULTS

The expression level of TBX2 was positively correlated with the stage of CSCC. CSCC tumor cell lines have significantly higher expression levels of TBX2 than normal skin cell lines, and SCC13 cells showed the highest expression. PD-L1 expressions were upregulated during the progression of CSCC, and positively correlated with TBX2. Furthermore, PD-L1 expression increased in SCC13 cells overexpressing TBX2. However, TBX2 did not regulate the activation of IFNγ signal, but mediated the expression of interferon regulatory factor 1 (IRF1) and PD-L1 in both SCC13 and PDV cells.

CONCLUSION

TBX2 could mediate antitumor immune response in CSCC by regulating the expression of PD-L1 through IRF1. It might be a prognostic marker in CSCC and synergistic target for PD-1 immunotherapy.

TBX2 overexpression promotes proliferation and invasion through epithelial-mesenchymal transition and ERK signaling pathway

The present study aimed to clarify the clinical significance and biological effects of T-box (TBX)2 and its potential mechanism in gastric cancer (GC). TBX2 protein expression levels in human GC tissues were investigated using immunohistochemistry, and it was demonstrated that TBX2 was overexpressed in 55.9% (90/161) GC samples. TBX2 overexpression correlated with tumor invasion, advanced tumor node metastasis stage and presence of lymph node metastasis. In addition, TBX2 correlated with poor patient survival. To investigate the effect of TBX2 on biological behaviors, TBX2 plasmid transfection was performed in SGC-7901 cells and TBX2 small interfering RNA knockdown was carried out in BGC-823 cells. MTT and matrigel invasion assays demonstrated that TBX2 overexpression promoted proliferation and invasion, whereas TBX2 depletion inhibited proliferation and invasion. TBX2 overexpression also promoted epithelial-mesenchymal transition by downregulating E-cadherin and upregulating N-cadherin. TBX2 overexpression also upregulated matrix metalloproteinase (MMP)2, MMP9, cyclin E and phosphorylated-extracellular signal regulated kinase levels, however downregulated p21. In conclusion, TBX2 may serve as an effective predictor and therapeutic target in human GC.

Intranuclear delivery of the transcription modulation domain of Tbet-improved lupus nephritis in (NZB/NZW) F1 lupus-prone mice

Excessive expression of Tbet and IFNγ is evidence of systemic lupus erythematosus (SLE) in lupus patients. In this study, the nucleus-transducible form of Transcription Modulation Domain (TMD) of Tbet (ntTbet-TMD), which is a fusion protein between Protein Transduction Domain Hph-1 (Hph-1-PTD) and the TMD of Tbet comprising DNA binding domain and isotype-specific domain, was generated to inhibit Tbet-mediated transcription in the interactomic manner. ntTbet-TMD was effectively delivered into the nucleus of the cells and specifically inhibited Tbet-mediated transcription without influencing the differentiation of other T cell subsets and signaling events for T cell activation. The severity of nephritis was significantly reduced by ntTbet-TMD as effectively as methylprednisolone in lupus-prone mice. The number of Th1, Th2 or Th17 cells and the secretion of their cytokines substantially decreased in the spleen and kidney of lupus-prone mice by ntTbet-TMD treatment. In contrast to methylprednisolone, the marked increase of Treg cells and the secretion of their immunosuppressive cytokine were detected in the spleen of (NZB/NZW) F1 mice treated with ntTbet-TMD. Thus, ntTbet-TMD can improve nephritis in lupus-prone mice by modulating the overall proinflammatory microenvironment and rebalancing T cell subsets, leading to new immune therapeutics for Th1-mediated autoimmune diseases.

Eomesodermin promotes interferon-γ expression and binds to multiple conserved noncoding sequences across the Ifng locus in mouse thymoma cell lines

The T-box transcription factors T-bet and eomesodermin (Eomes) have been shown to regulate the lineage-specific expression of interferon-γ (IFN-γ). However, in contrast to T-bet, the role of Eomes in the expression of IFN-γ remains unclear. In this study, we investigated the Eomes-dependent expression of IFN-γ in the mouse thymoma BW5147 and EL4 cells, which do not express T-bet or Eomes. The ectopic expression of Eomes induced BW5147 and EL4 cells to produce IFN-γ in response to phorbol 12-myristate 13-acetate (PMA) and ionomycin (IM). In BW5147 cells, Eomes augmented luciferase activity driven by the Ifng promoter encoding from -2500 to +113 bp; however, it was not increased by a stimulation with PMA and IM. A chromatin immunoprecipitation assay showed that Eomes bound to the Ifng promoter and conserved noncoding sequence (CNS) -22 kb across the Ifng locus with high efficacy in BW5147 cells. Moreover, Eomes increased permissive histone modifications in the Ifng promoter and multiple CNSs. The stimulation with PMA and IM greatly augmented Eomes binding to CNS-54, CNS-34, CNS+19 and CNS+30, which was inhibited by FK506. These results indicated that Eomes bound to the Ifng promoter and multiple CNSs in stimulation-dependent and stimulation-independent manners.

Identification of a novel mechanism of action of fingolimod (FTY720) on human effector T cell function through TCF-1 upregulation

Background

Fingolimod (FTY720), the first oral treatment for multiple sclerosis (MS), blocks immune cell trafficking and prevents disease relapses by downregulation of sphingosine-1-phosphate receptor. We determined the effect of FTY720 on human T cell activation and effector function.

Methods

T cells from MS patients and healthy controls were isolated to measure gene expression profiles in the presence or absence of FTY720 using nanostring and quantitative real-time polymerase chain reaction (qPCR). Cytokine protein expression was measured using luminex assay and flow cytometry analysis. Lentivirus vector carrying short hairpin RNA (shRNA) was used to knock down the expression of specific genes in CD4+ T cells. Chromatin immunoprecipitation was performed to assess T cell factor 1 (TCF-1) binding to promoter regions. Luciferase assays were performed to test the direct regulation of interferon gamma (IFN-γ) and granzyme B (GZMB) by TCF-1. Western blot analysis was used to assess the phosphorylation status of Akt and GSK3β.

Results

We showed that FTY720 treatment not only affects T cell trafficking but also T cell activation. Patients treated with FTY720 showed a significant reduction in circulating CD4 T cells. Activation of T cells in presence of FTY720 showed a less inflammatory phenotype with reduced production of IFN-γ and GZMB. This decreased effector phenotype of FTY720-treated T cells was dependent on the upregulation of TCF-1. FTY720-induced TCF-1 downregulated the pathogenic cytokines IFN-γ and GZMB by binding to their promoter/enhancer regions and mediating epigenetic modifications. Furthermore, we observed that TCF-1 expression was lower in T cells from multiple sclerosis patients than in those from healthy individuals, and FTY720 treatment increased TCF-1 expression in multiple sclerosis patients.

Conclusions

These results reveal a previously unknown mechanism of the effect of FTY720 on human CD4+ T cell modulation in multiple sclerosis and demonstrate the role of TCF-1 in human T cell activation and effector function.

Electronic supplementary material

The online version of this article (doi:10.1186/s12974-015-0460-z) contains supplementary material, which is available to authorized users.

Genome-wide association analysis identifies three new risk loci for gout arthritis in Han Chinese

Gout is one of the most common types of inflammatory arthritis, caused by the deposition of monosodium urate crystals in and around the joints. Previous genome-wide association studies (GWASs) have identified many genetic loci associated with raised serum urate concentrations. However, hyperuricemia alone is not sufficient for the development of gout arthritis. Here we conduct a multistage GWAS in Han Chinese using 4,275 male gout patients and 6,272 normal male controls (1,255 cases and 1,848 controls were genome-wide genotyped), with an additional 1,644 hyperuricemic controls. We discover three new risk loci, 17q23.2 (rs11653176, P=1.36 × 10⁻¹³, BCAS3), 9p24.2 (rs12236871, P=1.48 × 10⁻¹⁰, RFX3) and 11p15.5 (rs179785, P=1.28 × 10⁻⁸, KCNQ1), which contain inflammatory candidate genes. Our results suggest that these loci are most likely related to the progression from hyperuricemia to inflammatory gout, which will provide new insights into the pathogenesis of gout arthritis.

Raised serum urate levels are a risk factor for gout, a common form of inflammatory arthritis. Here Li et al. conduct a multistage genome-wide association study in a Han Chinese population and identify three novel loci likely associated with the progression from hyperuricemia to gout.

c-Abl-mediated tyrosine phosphorylation of the T-bet DNA-binding domain regulates CD4+ T-cell differentiation and allergic lung inflammation

The tyrosine kinase c-Abl is required for full activation of T cells, while its role in T-cell differentiation has not been characterized. We report that c-Abl deficiency skews CD4(+) T cells to type 2 helper T cell (Th2) differentiation, and c-Abl(-/-) mice are more susceptible to allergic lung inflammation. c-Abl interacts with and phosphorylates T-bet, a Th1 lineage transcription factor. c-Abl-mediated phosphorylation enhances the transcriptional activation of T-bet. Interestingly, three tyrosine residues within the T-bet DNA-binding domain are the predominant sites of phosphorylation by c-Abl. Mutation of these tyrosine residues inhibits the promoter DNA-binding activity of T-bet. c-Abl regulates Th cell differentiation in a T-bet-dependent manner because genetic deletion of T-bet in CD4(+) T cells abolishes c-Abl-deficiency-mediated enhancement of Th2 differentiation. Reintroduction of T-bet-null CD4(+) T cells with wild-type T-bet, but not its tyrosine mutant, rescues gamma interferon (IFN-γ) production and inhibits Th2 cytokine production. Therefore, c-Abl catalyzes tyrosine phosphorylation of the DNA-binding domain of T-bet to regulate CD4(+) T cell differentiation.

Distinct gene signature revealed in white blood cells, CD4(+) and CD8(+) T cells in (NZBx NZW) F1 lupus mice after tolerization with anti-DNA Ig peptide

Tolerizing mice polygenically predisposed to lupus-like disease (NZB/NZW F1 females) with a peptide mimicking anti-DNA IgG sequences containing MHC class I and class II T cell determinants (pConsensus, pCons) results in protection from full-blown disease attributable in part to the induction of CD4(+)CD25(+)Foxp3+ and CD8(+)Foxp3+ regulatory T cells. We compared 45 000 murine genes in total white blood cells (WBC), CD4(+) T cells, and CD8(+) T cells from splenocytes of (NZBxNZW) F1 lupus-prone mice tolerized with pCons vs untreated naïve mice and found two-fold or greater differential expression for 448 WBC, 174 CD4, and 60 CD8 genes. We identified differentially expressed genes that played roles in the immune response and apoptosis. Using real-time PCR, we validated differential expression of selected genes (IFI202B, Bcl2, Foxp3, Trp-53, CCR7 and IFNar1) in the CD8(+)T cell microarray and determined expression of selected highly upregulated genes in different immune cell subsets. We also determined Smads expression in different immune cell subsets, including CD4(+) T cells and CD8(+) T cells, to detect the effects of TGF-beta, known to be the major cytokine that accounts for the suppressive capacity of CD8(+) Treg in this system. Silencing of anti-apoptotic gene Bcl2 or interferon genes (IFI202b and IFNar1 in combination) in CD8(+) T cells from tolerized mice did not affect the expression of the other selected genes. However, silencing of Foxp3 reduced expression of Foxp3, Ifi202b and PD1-all of which are involved in the suppressive capacity of CD8(+) Treg in this model.

Common themes emerge in the transcriptional control of T helper and developmental cell fate decisions regulated by the T-box, GATA and ROR families

Cellular differentiation requires the precise action of lineage-determining transcription factors. In the immune system, CD4(+) T helper cells differentiate into at least three distinct effector lineages, T helper type 1 (Th1), Th2 and Th17, with the fate of the cell at least in part determined by the transcription factors T-box expressed in T cells (T-bet), GATA-3 and retinoid-related orphan receptor gammat (RORgammat), respectively. Importantly, these transcription factors are members of larger families that are required for numerous developmental transitions from early embryogenesis into adulthood. Mutations in members of these transcription factor families are associated with a number of human genetic diseases due to a failure in completing lineage-specification events when the factor is dysregulated. Mechanistically, there are both common and distinct functional activities that are utilized by T-box, GATA and ROR family members to globally alter the cellular gene expression profiles at specific cell fate decision checkpoints. Therefore, understanding the molecular events that contribute to the ability of T-bet, GATA-3 and RORgammat to define T helper cell lineages can provide valuable information relevant to the establishment of other developmental systems and, conversely, information from diverse developmental systems may provide unexpected insights into the molecular mechanisms utilized in T helper cell differentiation.

Restoration of T-box-containing protein expressed in T cells protects against allergen-induced asthma

BACKGROUND

A T(H)1-specific transcription factor, T-box-containing protein expressed in T cells (T-bet), controls the production of both T(H)1 and T(H)2 cytokines in T(H) cell differentiation by means of distinct mechanisms. T-bet-deficient mice overproduce T(H)2 cytokines and have spontaneous airway inflammation.

OBJECTIVES

We tested whether T-bet overexpression could protect against the development or progression of asthma.

METHODS

We generated a T cell-specific and inducible line of T-bet-transgenic mice on a T-bet-deficient genetic background and used it to study the function of T-bet in an ovalbumin (OVA)-induced asthma model.

RESULTS

Induction of T-bet in a T cell-specific manner in an OVA model of asthma concomitant with OVA injection prevented airway hyperresponsiveness, eosinophilic and lymphocytic inflammation, and IL-5 and IL-13 production in bronchoalveolar lavage fluid and also reduced serum IgE and T(H)2 cytokine production by peripheral T cells. Even when T-bet expression was induced during later stages of asthma progression, T-bet overexpression still attenuated airway hyperresponsiveness and goblet cell hyperplasia, as well as T(H)2 cytokine production.

CONCLUSIONS

Our results suggest that T-bet expression in T cells can prevent the initiation of airway inflammation and progression of chronic inflammation and might be extrapolated to human asthma.