Project description:Objectives: Eph/Ephrin cell-cell signaling is emerging as a key player in tissue fibrogenesis. The aim of this study was to test the hypothesis that the receptor tyrosine kinase EphB2 mediates dermal fibrosis in systemic sclerosis (SSc). Methods: We assessed normal and SSc human skin biopsies for EphB2 expression. The in vivo role of EphB2 in skin fibrosis was investigated by subjecting EphB2-knockout mice to both bleomycin-induced and tight skin (Tsk1/+) genetic mouse models. EphB2 kinase-dead and overactive point mutant mice were used to evaluate the role of EphB2 forward signaling in bleomycin-induced dermal fibrosis. In vitro studies were performed on dermal fibroblasts from SSc patients and healthy controls, which was followed by in vivo analysis of fibroblast-specific EphB2 deficient mice. Results: Expression of EphB2 is upregulated in SSc skin tissue and explanted SSc dermal fibroblasts compared to healthy controls. EphB2 expression is elevated in two animal models of dermal fibrosis. In mice, EphB2 drives dermal fibrosis in both the bleomycin and the Tsk1/+ models of skin fibrosis. EphB2 forward signaling is a critical mediator of dermal fibrosis. Transforming growth factor-β (TGFβ) cytokines upregulate EphB2 in dermal fibroblasts via non-canonical TGFβ/SMAD signaling and silencing EphB2 in dermal fibroblasts is sufficient to dampen TGFβ-induced fibroblast-to-myofibroblast differentiation. Moreover, mice with fibroblast-specific deletion of EphB2 showed impaired fibroblast-to-myofibroblast differentiation and reduced skin fibrosis upon bleomycin challenge. Conclusion: Our data implicate EphB2 overexpression and kinase-mediated forward signaling in the development of dermal fibrosis in SSc. EphB2 thus represents a potential new therapeutic target for SSc.
Project description:LncRNA H19X was silienced in dermal fibroblats of systemic sclerosis patients with antisense oligonuclotides. The hypothesis tested in the present study was that H19X is an important factor in the development of TGFb-driven fibrosis. Results provide important information about the role H19X in fibroblasts in particolar on extracellular matrix production and cell cycle regulation.
Project description:Autoantibodies (Aab) are frequent in systemic sclerosis (SSc). While recognized as potent biomarkers, their pathogenic role is much debated. This study explored the effect of purified IgG from SSc patients on the phenotype and function of healthy dermal fibroblast (FB) using an innovative multi-omics approach.
Project description:Aberrant deposition of extracellular matrix (ECM) resulting in dermal fibrosis is a hallmark of systemic sclerosis (SSc). Evidence suggests that dysfunctional SSc keratinocytes may contribute to fibrosis by altering dermal homeostasis. Whether interleukin-25 (IL-25), an IL-17 family member involved in epithelial/mesenchymal/immune cell interplay takes part in skin fibrosis is unknown. Here we address the role of IL-25 in SSc skin fibrosis. Compared to healthy donor (HD), in SSc and scleroderma-like disorders the epidermis expressed significantly lower levels of IL-25. In epidermal equivalents, IL-25 regulated several molecular pathways related to wound healing and ECM remodeling. Compared to control conditioned medium (CM), the CM from IL-25-primed keratinocytes enhanced the production by fibroblasts of matrix metalloproteinase-1 (MMP-1), IL-6, IL-8 (p< 0.05), but not of type-I collagen (Col-I ) nor fibronectin. However, IL- 25 significantly reduced the production of Col-I when applied directly to fibroblasts. The activation of keratinocytes by IL-25 was receptor-dependent and evident after a very short incubation time (10 min), largely mediated by IL-1, suggesting enhanced and specific release of preformed mediators. These results show that IL-25 participates to skin homeostasis and its decreased expression in SSc may contribute to skin fibrosis by favoring ECM deposition over degradation.
Project description:Systemic sclerosis (SSc) is characterized by intractable multiorgan fibrosis caused by vascular and immune dysfunction. Currently, effective therapeutic options for patients with SSc are limited. Nitrate, an abundant nutrient in the diet, has been demonstrated to be preventative and therapeutic for several diseases. To determine whether nitrate can slow or reverse SSc progression, topical application of nitrate delivered by dissolving microneedles was used to treat a bleomycin (BLM)-induced dermal fibrosis mouse model. In this study, nitrate considerably attenuated dermal thickness, stiffness, and collagen deposition.To examine the nitrate regulation of gene expression at the genome-wide level, bulk RNA sequencing of skin was performed. Bulk RNA sequencing of skin revealed that Cd4 was a key hub gene in SSc nitrate therapy. Additionally, BLM-induced cytokines and chemokines were inhibited by nitrate, and CD4+ T cells infiltration markedly declined. Il4, Il6, Il13, and Tgfb expression in CD4+ T cells isolated from skin biopsies also significantly decreased. Mechanistically, Il1rl1, a type2 immune response inducer, was markedly repressed in isolated CD4+ T cells and dermal tissues after nitrate treatment. Remarkably, compared with wild type mice, mice lacking Il1rl1 showed impaired transcriptional profiles after intradermal BLM injection. Adoptive transfer of ST2+CD4+ T cells promoted bleomycin-induced Rag2-/- mice dermal fibrosis. Collectively, these findings demonstrate that nitrate targeting ST2+CD4+ T cells is an effective therapeutic option for SSc.
Project description:Systemic sclerosis (SSc) is an autoimmune, connective tissue disease characterized by vasculopathy and fibrosis of the skin and internal organs. Trends in efficacy outcome measures favored tofacitnib. Baseline gene expression in fibroblast and keratinocyte subpopulations indicates interferon (IFN) activated gene expression.
Project description:Fibrotic diseases impose a major socioeconomic challenge on modern societies with limited treatment options. Adropin, a peptide hormone encoded by the energy-homeostasis-associated (ENHO) gene, is implicated in metabolism and vascular homeostasis, but its role in the pathogenesis of fibrosis remains enigmatic. Here, we used machine learning approaches in combination with functional in vitro and in vivo experiments to characterize Adropin/ENHO as a potential regulator involved in fibroblast activation and tissue fibrosis in systemic sclerosis (SSc). We demonstrated consistent downregulation of Adropin/ENHO in SSc skin across different SSc cohorts. The prototypical profibrotic cytokine TGFβ reduced Adropin/ENHO expression in a JNK-dependent manner. Restoration of Adropin signaling by therapeutic application of bioactive Adropin34-76 peptides in turn inhibited TGFβ-induced fibroblast activation and fibrotic tissue remodeling in primary human dermal fibroblasts, three-dimensional full-thickness skin equivalents, the mouse models of bleomycin-induced pulmonary fibrosis and sclerodermatous chronic graft-versus-host-disease (sclGvHD), and precision-cut human skin slices (PCSS). Knockdown of GPR19, receptor of Adropin, abrogated the antifibrotic effects of Adropin in fibroblasts. RNA-seq demonstrated that the antifibrotic effects of Adropin34-76 were functionally linked to deactivation of GLI1 dependent profibrotic transcriptional networks, which was experimentally confirmed in vitro, in vivo and ex vivo. ChIP-seq confirmed Adropin34-76-induced changes in TGFβ/GLI1 signaling. Our study thus characterizes the TGFβ-induced downregulation of Adropin/ENHO expression as a potential pathomechanism of SSc as a prototypical systemic fibrotic disease that unleashes uncontrolled activation of profibrotic GLI1 signaling. We also provide evidence in multiple preclinical models that Adropin34-76 might offer potential for the treatment of fibrosis.
Project description:Fibrotic diseases impose a major socioeconomic challenge on modern societies with limited treatment options. Adropin, a peptide hormone encoded by the energy-homeostasis-associated (ENHO) gene, is implicated in metabolism and vascular homeostasis, but its role in the pathogenesis of fibrosis remains enigmatic. Here, we used machine learning approaches in combination with functional in vitro and in vivo experiments to characterize Adropin/ENHO as a potential regulator involved in fibroblast activation and tissue fibrosis in systemic sclerosis (SSc). We demonstrated consistent downregulation of Adropin/ENHO in SSc skin across different SSc cohorts. The prototypical profibrotic cytokine TGFβ reduced Adropin/ENHO expression in a JNK-dependent manner. Restoration of Adropin signaling by therapeutic application of bioactive Adropin34-76 peptides in turn inhibited TGFβ-induced fibroblast activation and fibrotic tissue remodeling in primary human dermal fibroblasts, three-dimensional full-thickness skin equivalents, the mouse models of bleomycin-induced pulmonary fibrosis and sclerodermatous chronic graft-versus-host-disease (sclGvHD), and precision-cut human skin slices (PCSS). Knockdown of GPR19, receptor of Adropin, abrogated the antifibrotic effects of Adropin in fibroblasts. RNA-seq demonstrated that the antifibrotic effects of Adropin34-76 were functionally linked to deactivation of GLI1 dependent profibrotic transcriptional networks, which was experimentally confirmed in vitro, in vivo and ex vivo. ChIP-seq confirmed Adropin34-76-induced changes in TGFβ/GLI1 signaling. Our study thus characterizes the TGFβ-induced downregulation of Adropin/ENHO expression as a potential pathomechanism of SSc as a prototypical systemic fibrotic disease that unleashes uncontrolled activation of profibrotic GLI1 signaling. We also provide evidence in multiple preclinical models that Adropin34-76 might offer potential for the treatment of fibrosis.
Project description:Systemic sclerosis is a connective tissue disease affecting skin and internal organs, characterized by a triad of inflammation, vasculopathy and progressive fibrosis, due to deposition of mainly type I collagen. Out of the intricate mechanisms involved in the pathogenesis of the disease, evidence indicates that TGFbeta signaling plays a central role in mediating the effects of several pro-fibrotic effectors. In addition, TGFbeta is induced by hypoxia in cultured fibroblasts, an observation suggesting a role for this cytokine in linking vasculopathy and fibrosis in the disease. Not surprisingly, TGFbeta and Wnt signaling are among the most prevalent pathways found in global gene expression studies performed on systemic sclerosis skin biopsies. In this perspective, modulation of TGFbeta activity remains a top therapeutic target in systemic sclerosis drug development. We recently performed whole-body magnetic resonance imaging (MRI) studies in systemic sclerosis patients, and evidenced deep connective tissue infiltrates surrounding tendons in patients with active disease, and tendon friction rubs. Tenosynovitis and arthritis were also found by MRI in one third of the patients. We performed tenosynovial biopsies in patients with clinically active tenosynovitis, in order to evaluate whether such samples would provide additional information on disease mechanisms. Here, we report that these samples are characterized by the over-expression of genes involved in fibrosis, TGFbeta/Wnt signaling, chemokines and cytokines, but also by the concurrent over-expression of several ubiquitin-specific peptidases (USPs). Among the USPs overexpressed in systemic sclerosis tenosynovial biopsies, USP15 is known to specifically deubiquitinate SMAD3, and the TGFbeta Receptor 1. These results triggered us to perform additional experiments in order to test whether USP15 overexpression plays a role in the pathogenesis of systemic sclerosis via decreased ubiquitin-mediated degradation of proteins involved in TGFbeta signaling.