IL-6 driven pSTAT1 response is linked to T cell features implicated in early immune dysregulation
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ABSTRACT: Here, we performed an in-depth characterization of the effect of classic IL-6 signaling in primary human T cells from healthy individuals. We generated a detailed map of IL-6 signaling in CD4+ and CD8+ naïve and memory T cell subsets, linking mbIL-6R expression levels to the magnitude and balance of phosphorylation of STAT1 and STAT3 and the transcriptomics response to IL-6 in these subsets.
Project description:Interleukin-6 (IL-6) plays an important role in progressive bone loss in rheumatoid arthritis (RA). However, the molecular mechanisms through which IL-6 propels RA synovial fibroblasts (RASFs) to contribute to bone loss are not fully understood. In the present study, we investigated the effects of IL-6 and IL-6 receptor (IL-6/IL-6R induced trans-signaling in human RASFs. Treatment of human RASFs with IL-6 and IL-6 receptor (IL-6/IL-6R, 100 ng/ml each) alone or in combination with M-CSF (2 ng/ml) and RANKL (10 ng/ml) for 12 days resulted in the phenotypic changes to osteoclast-like features as determined by increase in TRAP staining and enhanced pit formation by ~3-fold in bone resorption assay in vitro. IL-6/IL-6R induced a dose-dependent increase in the expression of transcription factor Ets2 and enhanced its nuclear translocation in human RASFs. Interestingly, the untargeted proteomics analysis of the conditioned media from IL6/IL6R activated RASFs using Mass-Spectrometry (MS) technique and Trans-Proteomic Pipeline tool showed the production of 113 analytes unique to IL-6/IL-6R stimulation. Further analysis of the proteomics data using STRING database for pathway analysis showed the impact of IL-6/IL-6R on immunometabolic reprogramming of human RASFs towards osteoclast-like phenotype, which was partly mediated through Ets2. These preliminary studies identified a novel role of IL-6/IL-6R-mediated trans signaling in the metabolic reprogramming in RASFs that could potentially be targeted by inhibiting Ets2 to limit their role in bone resorption in RA.
Project description:The pro-inflammatory cytokine IL-6 is elevated in both blood and airways in asthma. IL-6 signaling is regulated by its receptor composed of two proteins, IL-6R and GP130, that are found in both membrane and soluble forms. The interaction of IL-6 with soluble IL-6R (sIL-6R) can trigger IL-6 trans-signaling in cells such as epithelial cells and fibroblasts, which express GP130, but do not produce sufficient IL-6R. We aimed to analyze IL-6 trans-signaling in the airways after an allergen challenge and to examine the potential source of sIL-6R and sGP130. In addition to protein analysis of bronchoalveolar lavages by ELISA and flow cytometry, we performed next-generation RNA sequencing (RNA-seq) to study the expression of the IL-6R subunits by eosinophils activated by IL-3 in vitro. RNA-seq and proteomic analyses confirmed that eosinophils do not produce GP130 but produce both IL-6R and ADAM10, a metalloproteinase that cleaves membrane IL-6R into sIL-6R.
Project description:Elevated levels and enhanced sensing of the pro-inflammatory cytokine interleukin-6 (IL-6) are key features of many autoimmune and inflammatory diseases. To better understand how IL-6 signaling may influence human T cell fate, we investigated the relationships between levels of components of the IL-6R complex, pSTAT responses, and transcriptomic and translational changes in CD4+ and CD8+ T cell subsets from healthy individuals after exposure to IL-6. Our findings highlight the striking heterogeneity in mbIL-6R and gp130 expression and IL-6-driven pSTAT1/3 responses across T cell subsets. Increased mbIL-6R expression correlated with enhanced signaling via pSTAT1 with less impact on pSTAT3, most strikingly in CD4+ naïve T cells. Additionally, IL-6 rapidly induced expression of transcription factors and surface receptors expressed by T follicular helper cells and altered expression of markers of apoptosis. Importantly, many of the features associated with the level of mbIL-6R expression on T cells were recapitulated both in the setting of tocilizumab therapy and when comparing donor CD4+ T cells harboring the genetic variant, IL6R Asp358Ala (rs2228145), known to alter mbIL-6R expression on T cells. Collectively, these findings should be taken into account as we consider the role of IL-6 in disease pathogenesis and translating IL-6 biology into effective therapies for T cell-mediated autoimmune disease.
Project description:IL-6 is a proinflammatory cytokine implicated in multiple autoimmune diseases. Here we show that IL-6 induced STAT3 and STAT1 phosphorylation is enhanced in CD4 and CD8 T cells from patients with T1D compared to healthy controls. Enhanced IL-6/pSTAT3 is associated with increased surface IL-6R and early clinical disease. The transcriptome of IL-6 treated CD4 T cells from T1D patients reveals upregulation of genes involved in T cell migration. The data suggest that individuals with type 1 diabetes may benefit from therapeutic targeting of the IL-6 pathway.
Project description:Background: Monocytes play a crucial role in innate immune responses for host defense, yet their involvement in chronic obstructive pulmonary disease (COPD) remains poorly understood. We previously identified a subset of monocytes in COPD lung tissues characterized by high interleukin-6 receptor (IL-6R) expression. This study aimed to characterize the phenotypes of IL-6Rhi monocytes in the lung of COPD patients. Methods: Using flow cytometry, we assessed the abundance of pulmonary CD14+IL-6Rhi cells in never smokers (CNS), control ex-smokers (CES) and COPD patients. IL-6 expression in CD14+ monocytes from peripheral blood of patients with COPD was also examined. CD45+CD206–CD14+IL-6Rhi and CD45+CD206–CD14+IL-6R– cells were isolated from COPD lung tissues for transcriptome analysis. A monocyte line THP1 cell with constitutive IL-6R expression was stimulated with recombinant IL-6, followed by RNA sequencing to evaluate IL-6 responsiveness of IL-6R+ monocytes. Results: The number of pulmonary CD14+IL-6Rhi monocytes was elevated in COPD patients compared to CNS, while CD14+ monocytes in the peripheral blood of COPD patients did not express IL-6R. Upregulated mRNA expression in CD14+IL-6Rhi monocytes was associated with chemotaxis, monocyte differentiation, fatty acid metabolism and integrin-mediated signaling pathway. Stimulation of THP1 cells with recombinant IL-6 induced gene expression changes linked to chemotaxis and organism development. Conclusion: In patients with COPD, CD14+IL-6Rhi monocytes increase in lung tissues compared to CNS and exhibit a different transcriptome profile from CD14+IL-6R– monocytes.
Project description:Background: Monocytes play a crucial role in innate immune responses for host defense, yet their involvement in chronic obstructive pulmonary disease (COPD) remains poorly understood. We previously identified a subset of monocytes in COPD lung tissues characterized by high interleukin-6 receptor (IL-6R) expression. This study aimed to characterize the phenotypes of IL-6Rhi monocytes in the lung of COPD patients. Methods: Using flow cytometry, we assessed the abundance of pulmonary CD14+IL-6Rhi cells in never smokers (CNS), control ex-smokers (CES) and COPD patients. IL-6 expression in CD14+ monocytes from peripheral blood of patients with COPD was also examined. CD45+CD206–CD14+IL-6Rhi and CD45+CD206–CD14+IL-6R– cells were isolated from COPD lung tissues for transcriptome analysis. A monocyte line THP1 cell with constitutive IL-6R expression was stimulated with recombinant IL-6, followed by RNA sequencing to evaluate IL-6 responsiveness of IL-6R+ monocytes. Results: The number of pulmonary CD14+IL-6Rhi monocytes was elevated in COPD patients compared to CNS, while CD14+ monocytes in the peripheral blood of COPD patients did not express IL-6R. Upregulated mRNA expression in CD14+IL-6Rhi monocytes was associated with chemotaxis, monocyte differentiation, fatty acid metabolism and integrin-mediated signaling pathway. Stimulation of THP1 cells with recombinant IL-6 induced gene expression changes linked to chemotaxis and organism development. Conclusion: In patients with COPD, CD14+IL-6Rhi monocytes increase in lung tissues compared to CNS and exhibit a different transcriptome profile from CD14+IL-6R– monocytes.
Project description:BACKGROUND - IL-6 mediates graft-versus-host disease (GVHD) in experimental allogeneic stem cell transplantation (alloSCT) and is an attractive therapeutic target. METHODS - A registered phase I/II study (ACTRN12612000726853) of IL-6 receptor (IL-6R) neutralizing antibody administration on day -1 to patients receiving full or reduced-intensity conditioning (RIC) and alloSCT from HLA-matched sibling or unrelated donors with standard cyclosporin and methotrexate GVHD prophylaxis. The primary endpoint was incidence of grade II-IV acute GVHD. Outcomes were compared to a non-randomized but contemporaneous group of study patients receiving the same alloSCT in the absence of IL-6R mAb. FINDINGS - Cytokine and pharmacokinetic analysis confirmed transient IL-6 dysregulation in the first month after alloSCT with complete inhibition following IL-6R mAb administration. With median follow up of 497 days, the incidence of grade II-IV GVHD was 12.5% in recipients of IL-6R inhibition (n = 48) versus 41.5% in the (n = 53) control cohort (P = 0.001). Low rates of acute GVHD were noted in patients receiving IL-6R inhibition relative to control patients following both myeloablative (12.5% vs. 46.4%, P = 0.03) and RIC (12.5% vs. 36.0%, P = 0.04). The incidence of severe (grade III/IV) acute GVHD was 4.2% in recipients of IL-6R inhibition versus 20.8% in the control cohort (P = 0.012). Relapse and chronic GVHD were unchanged. Immune reconstitution was preserved in recipients of IL-6R inhibition, but qualitatively modified with suppression of known pathogenic STAT3-dependent pathways. INTERPRETATION - IL-6 is the principal detectable and dysregulated cytokine secreted after alloSCT and its inhibition is a potential new and simple strategy to protect from acute GVHD despite robust immune reconstitution and a sustained graft-versus-leukemia effect. Single colour, Illumina Human HT12v4 Beadarrays.
Project description:Interleukin-21 (IL-21) is a type 1 cytokine essential for immune cell differentiation and function. Although IL-21 can activate several STAT family transcription factors, previous studies focused mainly on the role of STAT3 in IL-21 signaling. Here, we investigated the role of STAT1 and show that STAT1 and STAT3 have at least partially opposing roles in IL-21 signaling in CD4+ T cells. IL-21 induced STAT1 phosphorylation, and this was augmented in Stat3-deficient CD4+ T cells. RNA-Seq analysis of CD4+ T cells from Stat1- and Stat3-deficient mice revealed that both STAT1 and STAT3 are critical for IL-21-mediated gene regulation. Expression of some genes, including Tbx21 and Ifng, was differentially regulated by STAT1 and STAT3, and interestingly, ChIP-Seq analysis showed that STAT3 binding at Tbx21 and Ifng loci was attenuated in Stat1-deficient cells. Moreover, opposing actions of STAT1 and STAT3 on IFN- expression in CD4+ T cells were demonstrated in vivo during chronic lymphocytic choriomeningitis (LCMV) infection. Finally, IL-21-mediated induction of STAT1 phosphorylation, as well as IFNG and TBX21 expression, were higher in CD4+ T cells from patients with autosomal dominant hyper-IgE syndrome (AD-HIES), which is caused by STAT3 deficiency. These data indicate an interplay between STAT1 and STAT3 in fine-tuning IL-21 actions. Genome-wide transcription factors mapping and binding of STAT3 in mouse CD4+ T cells in both WT and Stat1-deficient mice. RNA-Seq is performed in mouse CD4+ T cells in WT, Stat1-deficient and Stat3-deficient mice.
Project description:Protection against endothelial damage is recognized as a frontline approach to preventing the progression of cytokine release syndrome (CRS). Accumulating evidence has demonstrated that interleukin-6 (IL-6) promotes vascular endothelial damage during CRS, although the molecular mechanisms remain to be fully elucidated. Targeting IL-6 receptor signaling delays CRS progression; however, current options are limited by persistent inhibition of the immune system. Here, we show that endothelial IL-6 trans-signaling promoted vascular damage and inflammatory responses via hypoxia-inducible factor-1α (HIF1α)‒induced glycolysis. Using pharmacological inhibitors targeting HIF1α activity or mice with the genetic ablation of gp130 in the endothelium, we found that inhibition of IL-6R‒HIF1α signaling in endothelial cells protected against vascular injury caused by septic damage and provided survival benefit in a mouse model of sepsis. In addition, we developed a short half-life anti-IL-6R antibody (silent anti-IL-6R antibody) and found that it was highly effective at augmenting survival for sepsis and severe burn by strengthening the endothelial glycocalyx and reducing cytokine storm, and vascular leakage. Together, our data advance the role of endothelial IL-6 trans-signaling in the progression of CRS and indicate a potential therapeutic approach for burns to address the lack of burn-specific treatments.