The expanding role of IL-7 and thymic stromal lymphopoietin as therapeutic target for rheumatoid arthritis

Interleukin-7 regulates CD127 expression and promotes CD8+ T cell activity in patients with primary cutaneous melanoma

Background

Interleukin (IL)-7 signaling through CD127 is impaired in lymphocytes in cancers and chronic infections, resulting in CD8⁺ T cell exhaustion. The mechanisms underlying CD8⁺ T cell responses to IL-7 in melanoma remain not completely elucidated. We previously showed reduced IL-7 level in melanoma patients. Thus, the aim of this study was to investigate the effect of IL-7 regulation on CD127 expression and CD8⁺ T cell responses in melanoma.

Methods

Healthy controls and primary cutaneous melanoma patients were enrolled. Membrane-bound CD127 (mCD127) expression on CD8⁺ T cells was determined by flow cytometry. Soluble CD127 (sCD127) protein level was measured by ELISA. Total CD127 and sCD127 mRNA level was measured by real-time PCR. CD8⁺ T cells were stimulated with recombinant human IL-7, along with signaling pathway inhibitors. CD8⁺ T cells were co-cultured with melanoma cell line, and the cytotoxicity of CD8⁺ T cells was assessed by measurement of lactate dehydrogenase expression.

Results

Plasma sCD127 was lower in melanoma patients compared with controls. The percentage of CD8⁺ T cells expressing mCD127 was higher, while sCD127 mRNA level was lower in peripheral and tumor-infiltrating CD8⁺ T cells from melanoma patients. There was no significant difference of total CD127 mRNA expression in CD8⁺ T cells between groups. IL-7 stimulation enhanced total CD127 and sCD127 mRNA expression and sCD127 release by CD8⁺ T cells. However, mCD127 mRNA expression on CD8⁺ T cells was not affected. This process was mainly mediated by phosphatidylinositol 3-kinase (PI3K) pathway. CD8⁺ T cells from melanoma patients exhibited decreased cytotoxicity. IL-7 stimulation promoted CD8⁺ T cell cytotoxicity, while inhibition of PI3K dampened IL-7-induced elevation of CD8⁺ T cell cytotoxicity.

Conclusion

The current data suggested that insufficient IL-7 secretion might contribute to CD8⁺ T cell exhaustion and CD127 dysregulation in patients with primary cutaneous melanoma.

The Association of IL7R rs6897932 with Risk of Multiple Sclerosis in Southern Chinese

OBJECTIVE

To investigate the association between IL7R rs6897932 and multiple sclerosis (MS) in southern Chinese people.

METHODS

In total, 147 MS patients and 530 healthy controls were recruited according to the revised McDonald criteria. The TaqMan method was used for genotyping.

RESULTS

With genetic models, we can observe that the additive model, the dominant model, and the recessive model of IL7R rs6897932 were significantly associated with MS [additive model: p=0.032; dominant model (adjusted): p<0.001, OR=3.61 (95% CI 2.25-5.83); recessive model (adjusted): p<0.001, OR=6.80 (95% CI 3.49-13.89)].

CONCLUSION

Our results suggest that IL7R rs6897932 is associated with MS in a southern Chinese population. More and larger MS studies to explore the genetic risk factors of MS are warranted.

Interleukin-7 aggravates myocardial ischaemia/reperfusion injury by regulating macrophage infiltration and polarization

Interleukin (IL)‐7 is known to enhance the macrophages cytotoxic activity and that macrophages play a pivotal role in the development and progression of myocardial ischaemia/reperfusion (I/R) injury. However, the effects of IL‐7 on macrophages infiltration and polarization in myocardial I/R injury are currently unclear. This study aimed to evaluate the effects of the IL‐7 expression on myocardial I/R injury and their relationship with macrophages. The data showed that IL‐7 expression in mouse heart tissue increases following I/R injury and that IL‐7 knockout or anti‐IL‐7 antibody treatment significantly improve I/R injury, including reduction in myocardial infarction area, a serum troponin T level decreases and an improvement in cardiac function. On the other hand, recombinant IL‐7 (rIL‐7) supplementation induces opposite effects and the anti‐IL‐7 antibody significantly reduces the cardiomyocyte apoptosis and macrophage infiltration. rIL‐7 cannot directly cause apoptosis, but it can induce cardiomyocyte apoptosis through macrophages, in addition to increase the macrophages migration in vitro. Anti‐IL‐7 antibody affects the cytokine production in T helper (Th) 1 and Th2 cells and also promotes the macrophages differentiation to M2 macrophages. However, anti‐IL‐7 antibody does not reduce the M1 macrophage number, and it only increases the ratio of M2/M1 macrophages in mice heart tissues after I/R injury. Taking together, these data reveal that IL‐7 plays an intensifying role in myocardial I/R injury by promoting cardiomyocyte apoptosis through the regulation of macrophage infiltration and polarization.

Serum cytokines and their predictive value in pulmonary involvement of systemic sclerosis

Objective

To identify serum cytokines which predict mortality and/or disease progression in patients with systemic sclerosis, especially with pulmonary involvement.

Methods

Serum cytokines (IL-6, IL-7, IL-8, IL-10, CCL2, CCL4, TGF-β, TNF-α) were measured in 125 SSc patients, who were recruited and observed in our outpatient clinic. Of these, 60 had pulmonary involvement, classified as either interstitial lung disease (ILD, 43 patients), pulmonary arterial hypertension (PAH, 7 patients) or pulmonary hypertension and ILD (PH-ILD, 10 patients). The association of serum cytokines with clinical features was analysed and their correlation with BAL cytokines measured in a subset of SSc patients with ILD.

Results

Serum cytokines were detected at different levels: high (TGF-β, median 287.5 pg/ml; CCL2, median 89.7 pg/ml; CCL4, median 104.2 pg/ml), low (IL-6, median 3.2 pg/ml; IL-7 median 2.3 pg/ml; IL-8, median 5.2 pg/ml; TNF-α, median 0 pg/ml but with a bimodal distribution) and very low (IL-10, median 0.4 pg/ml). IL-6 and IL-7 were predictive for death in a Cox regression analysis in all SSc patients as well as in all patients with pulmonary involvement; IL-6 was predictive for mortality in SSc-ILD patients. In a multivariate analysis, cytokine levels could also predict a change in lung function, e.g. IL-7 was a predictor for a decline of diffusion capacity (DLCO) by 20 or 30% in ILD patients. In a subset of ILD patients, serum cytokines were compared to BAL cytokines, but revealed only few correlations.

Conclusion

In conclusion, the analysis of serum cytokines implicates a role as biomarkers, distinct from BAL.

Elevated expression of TSLP and IL-33 in Behçet's disease skin lesions: IL-37 alleviate inflammatory effect of TSLP

The release of TSLP and IL-33 affect the skin integrity, which unsettled transcription factor regulators. We investigate TSLP and IL-33 in Behçet disease (BD) and we prove the effect of the anti-inflammatory cytokine IL-37 in BD skin lesions on TSLP production. TSLP, IL-33 and GATA-3/T-bet, were measured using PCR in BD skin lesions. We tested the suppressive effect of IL-37 on skin samples stimulated with a cytokine mixture inducing TSLP expression. TSLP and IL-33 were increased in BD patients particularly in patients having skin manifestations and correlate with indexed skin lesions. TSLP expression in BD with skin lesions correlates significantly with the transcription factors GATA3/Tbet ratio. The anti-inflammatory mediator IL-37 acted as a suppressor of TSLP-skin synthesis. The microenvironment in cutaneous lesions of BD patients' skin lesions is dominated by the expression of IL-33 and TSLP along an inflammatory Th2-type current. IL-37 acts as a booster to restore homeostasis.

Variants in the IL7RA gene confer susceptibility to multiple sclerosis in Caucasians: evidence based on 9734 cases and 10436 controls

Recently, numerous genome wide association studies (GWAS) and other case-control association studies examining the relationship between interleukin-7 receptor α chain (IL7RA) gene rs3194051, rs987107, rs11567686, and rs11567685 variants and multiple sclerosis (MS) risk have been conducted, but the conclusions have been inconsistent. The main objective of this meta-analysis was to more precisely explore the association of these four IL7RA variants with MS development. Twenty-seven eligible studies involving 9734 cases and 10436 controls were included in the present meta-analysis. Power calculation, publication bias, sensitivity analysis and cumulative meta-analysis were performed to derive a reliable conclusion. Our study indicated three IL7RA loci were significantly associated with increasing MS risk (rs3194051: recessive model: OR = 1.22, 95% CI 1.08–1.38; rs987107: recessive model: OR = 1.44, 95% CI 1.22–1.69; and rs11567686: dominant model: OR = 1.18, 95% CI 1.01–1.37). Additionally, IL7RA rs11567685 variants might not be related to MS development. In all, IL7RA locus polymorphisms could play an important role in the predisposition to MS, which could contribute to a better understanding the pathogenesis of multiple sclerosis.

Blockade of IL-7Rα alleviates collagen-induced arthritis via inhibiting Th1 cell differentiation and CD4+ T cell migration

T cell response is crucial to the pathogenesis and progression of rheumatoid arthritis (RA). IL-7/IL-7R axis has significant effect on CD4⁺ T cell response, including proliferation, differentiation, survival and migration. However, whether blockade of IL-7/IL-7R axis signaling can relieve RA and what is the potential treatment mechanisms are still remaining unclear. In this paper, we established collagen-induced arthritis (CIA) model and observed the effect of IL-7Rα antibody in the treatment of CIA mice. It is demonstrated that IL-7Rα antibody significantly alleviated clinical symptoms of CIA mice, accompanied with reduced CD4⁺ T cell number in both spleen and joints. Decreased CII-specific CD4⁺ T cell proliferation and reduced mRNA expression of inflammatory cytokines in IL-7Rα antibody-treated mice were observed. Subsequently, IL-7Rα antibody treatment in vivo downregulated the percentages of Th1 and Th17 cells and the mRNA expression of T-bet and RORγt gene. Moreover, it was found that IL-7 promoted Th1 cell differentiation in vitro, while having no effect on Th17 cell differentiation. In addition, administration of IL-7Rα antibody reduced the mRNA expression of chemokine receptors (CCR7, CXCR3, CXCR6 and XCR1) on CD4⁺ T cells and chemokine CXCL2 in joints. The results suggested that IL-7Rα antibody treated CIA mice via the inhibition of CII-specific CD4⁺ T cell proliferation, the reduction of Th1 cell differentiation and the restrain of CD4⁺ T cell migration to joint lesion site. This investigation indicates that IL-7Rα is a potential therapeutic target for RA.

The importance of TSLP in allergic disease and its role as a potential therapeutic target

Thymic stromal lymphopoietin (TSLP) is an epithelial-derived cytokine similar to IL- 7, whose gene is located on chromosome 5q22.1 and it exerts its biological function through the TSLP-Receptor (TSLP-R). TSLP is expressed primarily by epithelial cells at barrier surfaces such as the skin, gut and lung in response to danger signals. Since it was cloned in 1994, there has been accumulating evidence that TSLP is crucial for the maturation of antigen presenting cells and hematopoietic cells. TSLP genetic variants and its dysregulated expression have been linked to atopic diseases such as atopic dermatitis, asthma, allergic rhinitis and eosinophilic esophagitis.

Metal complexes as potential modulators of inflammatory and autoimmune responses

Over the past few decades, the realm of inorganic medicinal chemistry has been dominated by the study of the anti-cancer properties of transition metal complexes, particularly those based on platinum or ruthenium. However, comparatively less attention has been focused on the development of metal complexes for the treatment of inflammatory or autoimmune diseases. Metal complexes possess a number of advantages that render them as attractive alternatives to organic small molecules for the development of therapeutic agents. In this perspective, we highlight recent examples in the development of transition metal complexes as modulators of inflammatory and autoimmune responses. The studies presented here serve to highlight the potential of transition metal complexes in modulating inflammatory or immune pathways in cells.