Preclinical and translational research to discover potentially effective antifibrotic therapies in systemic sclerosis. Curr Opin Rheumatol. 2013;25:679-685. [PMID: 24047603 DOI: 10.1097/01.bor.0000434598.51526.0e]

Dermal fibroblasts have different extracellular matrix profiles induced by TGF-β, PDGF and IL-6 in a model for skin fibrosis

Different stimulants might induce different extracellular matrix profiles. It is essential to gain an understanding and quantification of these changes to allow for focused anti-fibrotic drug development. This study investigated the expression of extracellular matrix by dermal fibroblast mimicking fibrotic skin diseases as SSc using clinically validated biomarkers. Primary healthy human dermal fibroblasts were grown in media containing FICOLL. The cells were stimulated with PDGF-AB, TGF-β1, or IL-6. Anti-fibrotic compounds (iALK-5, Nintedanib) were added together with growth factors. Biomarkers of collagen formation and degradation together with fibronectin were evaluated by ELISAs in the collected supernatant. Immunohistochemical staining was performed to visualize fibroblasts and proteins, while selected gene expression levels were examined through qPCR. TGF-β and PDGF, and to a lesser extent IL-6, increased the metabolic activity of the fibroblasts. TGF-β primarily increased type I collagen and fibronectin protein and gene expression together with αSMA. PDGF stimulation resulted in increased type III and VI collagen formation and gene expression. IL-6 decreased fibronectin levels. iALK5 could inhibit TGF-β induced fibrosis while nintedanib could halt fibrosis induced by TGF-β or PDGF. Tocilizumab could not inhibit fibrosis induced in this model. The extent and nature of fibrosis are dependent on the stimulant. The model has potential as a pre-clinical model as the fibroblasts fibrotic phenotype could be reversed by an ALK5 inhibitor and Nintedanib.

Translational engagement of lysophosphatidic acid receptor 1 in skin fibrosis: from dermal fibroblasts of patients with scleroderma to tight skin 1 mouse

Background and Purpose

Genetic deletion and pharmacological studies suggest a role for lysophosphatidic acid (LPA₁) receptor in fibrosis. We investigated the therapeutic potential in systemic sclerosis (SSc) of a new orally active selective LPA₁ receptor antagonist using dermal fibroblasts from patients and an animal model of skin fibrosis.

Experimental Approach

Dermal fibroblast and skin biopsies from systemic sclerosis patients were used. Myofibroblast differentiation, gene expression and cytokine secretion were measured following LPA and/or SAR100842 treatment. Pharmacolgical effect of SAR100842 was assessed in the tight skin 1 (Tsk1) mouse model.

Key Results

SAR100842 is equipotent against various LPA isoforms. Dermal fibroblasts and skin biopsies from patients with systemic sclerosis expressed high levels of LPA₁ receptor. The LPA functional response (Ca²⁺) in systemic sclerosis dermal fibroblasts was fully antagonized with SAR100842. LPA induced myofibroblast differentiation in systemic sclerosis dermal and idiopathic pulmonary fibrosis lung fibroblasts and the secretion of inflammatory markers and activated Wnt markers. Results from systemic sclerosis dermal fibroblasts mirror those obtained in a mouse Tsk1 model of skin fibrosis. Using a therapeutic protocol, SAR100842 consistently reversed dermal thickening, inhibited myofibroblast differentiation and reduced skin collagen content. Inflammatory and Wnt pathway markers were also inhibited by SAR100842 in the skin of Tsk1 mice.

Conclusion and Implications

The effects of SAR100842 on LPA‐induced inflammation and on mechanisms linked to fibrosis like myofibroblast differentiation and Wnt pathway activation indicate that LPA₁ receptor activation plays a key role in skin fibrosis. Our results support the therapeutic potential of LPA₁ receptor antagonists in systemic sclerosis.

Involvement of the myeloid cell compartment in fibrogenesis and systemic sclerosis

Systemic sclerosis (SSc) is an autoimmune fibrotic disease of unknown aetiology that is characterized by vascular changes in the skin and visceral organs. Autologous haematopoietic stem cell transplantation can improve skin and organ fibrosis in patients with progressive disease and a high risk of organ failure, indicating that cells originating in the bone marrow are important contributors to the pathogenesis of SSc. Animal studies also indicate a pivotal function of myeloid cells in the development of fibrosis leading to changes in the tissue architecture and dysfunction in multiple organs such as the heart, lungs, liver and kidney. In this Review, we summarize current knowledge about the function of myeloid cells in fibrogenesis that occurs in patients with SSc. Targeted therapies currently in clinical studies for SSc might affect myeloid cell-related pathways. Therefore, myeloid cells might be used as cellular biomarkers of disease through the application of high-dimensional techniques such as mass cytometry and single-cell RNA sequencing.

Experimental Mouse Model of Bleomycin-Induced Skin Fibrosis

Systemic sclerosis (SSc) refers to an autoimmune disease, which is manifested by inflammation, vasculopathy, and fibrosis of the skin and internal organs. There are a number of different animal models recapitulating specific aspects of SSc. The experimental mouse model of bleomycin-induced skin fibrosis is commonly used to study the pathogenesis observed in SSc. In this model, repetitive intradermal injections of the cytotoxic agent bleomycin trigger progressive skin thickening, associated with excessive accumulation of collagen, infiltration of immune cells, and formation of α-smooth muscle actin (α-SMA)-positive myofibroblasts. In this article, we provide a detailed protocol for the induction of skin fibrosis in experimental mice by bleomycin. Moreover, we describe procedures for processing and analyzing affected skin tissue, provide troubleshooting, highlight advantages and limitations of the presented model, and critically discuss representative results. © 2019 by John Wiley & Sons, Inc. Basic Protocol 1: Intradermal bleomycin injections to induce skin fibrosis in mice Support Protocol: Mouse tissue collection for fibrosis evaluation and for other molecular assays Basic Protocol 2: Evaluation of mouse skin thickness using Masson's trichrome staining Basic Protocol 3: Measurement of hydroxyproline content in skin tissue using a colorimetric assay Basic Protocol 4: Evaluation of myofibroblasts in mouse skin by immunohistochemistry.

Effect of endothelin-1 receptor antagonists on skin fibrosis in scleroderma patients from the EUSTAR database

Introduction

The aim of the study was to evaluate the effect of endothelin-1 receptor antagonists (ETRAs) on skin fibrosis in systemic sclerosis (SSc) patients from the (EULAR Scleroderma Trials and Research) EUSTAR cohort.

Methods

SSc patients from the EUSTAR cohort with at least three visits (pre-study visit without ETRA treatment, baseline and follow-up visit with ETRA treatment) were included. The control group consisted of SSc patients with the same inclusion criteria, but without ETRA treatment. The primary endpoint was the comparison of the delta change of the modified Rodnan skin score (mRSS) between baseline and follow-up in the ETRA versus the control group.

Results

Data on 75 ETRA treated (68 bosentan, 1 sitaxentan, 6 ambrisentan) and 969 control patients were included. The delta change of mRSS was not significantly different between the ETRA group and the control group (n = 969; 0 (-2-1) vs. n = 75; 0 (-2-1); p = 0.4). Similarly, subgroup analysis on patients with diffuse, extended SSc disease (mRSS ≥16) did not show differences in the delta change of mRSS between the ETRA group and the control group (n = 125; −1 [-7-0] vs. n = 23; −1 [-7-2], p = 0.8). Likewise, diffuse SSc patients with mRSS 7-21 at baseline, reflecting recently identified enrichment criteria for clinical trials, did not show any difference between the ETRA and the control group (n = 219; −1 [-3-1] vs. n = 27; −1 [-3-2]; p = 0.5).

Conclusions

This controlled, observational, real-life cohort study with a large sample size did not show effects of ETRAs on skin fibrosis in patients with SSc.

Wenyang Huazhuo Tongluo formula, a Chinese herbal decoction, improves skin fibrosis by promoting apoptosis and inhibiting proliferation through down-regulation of survivin and cyclin D1 in systemic sclerosis

Background

Fibrosis is a major contributor to systemic sclerosis (SSc)-related morbidity, and rapid, progressive skin involvement predicts later mortality. Western medicine therapies for SSc cannot produce satisfactory effects currently, while Traditional Chinese Medicine (TCM), such as the Wenyang Huazhuo Tongluo (WYHZTL) formula, a Chinese herbal decoction, has shown amazing anti-fibrosis efficacy on SSc in clinical applications. This study is aiming to investigate the anti-fibrotic mechanism of WYHZTL formula for the treatment of SSc.

Methods

Fibroblasts from primary culture of skin lesions of SSc patients were exposed to rat medicated sera containing WYHZTL or XAV939, a small-molecule inhibitor of both tankyrase 1/2 and Wnt/β-catenin pathway. Cell counting kit-8 assay and Annexin V FITC/PI apoptosis kit were used to analyze cell proliferation and apoptosis in fibroblasts, respectively. Reverse transcription-polymerase chain reaction (RT-PCR) and western blotting were used to detect the mRNA and protein levels of cyclin D1 and survivin.

Results

After 28, 48 and 72 h of incubation, the proliferative ability of the fibroblasts cells was obviously reduced by the sera containing WYHZTL compared with that in the control group; the percentage of apoptotic cell population in the sera containing WYHZTL treated fibroblasts cells was significantly higher than that in those treated with the control sera, and was about similar to that in those treated with XAV939. The sera containing WYHZTL could down-regulate both mRNA and protein levels of cyclin D1 and survivin, compared with the control group.

Conclusions

The present study demonstrates the antiproliferative and pro-apoptotic actions of WYHZTL formula against fibroblasts and the effect may be related to the down-regulation of mRNA and protein levels of cyclin D1 and survivin in SSc.

Systemic sclerosis and localized scleroderma--current concepts and novel targets for therapy

Systemic sclerosis (SSc) is a chronic autoimmune disease with a high morbidity and mortality. Skin and organ fibrosis are key manifestations of SSc, for which no generally accepted therapy is available. Thus, there is a high unmet need for novel anti-fibrotic therapeutic strategies in SSc. At the same time, important progress has been made in the identification and characterization of potential molecular targets in fibrotic diseases over the recent years. In this review, we have selected four targeted therapies, which are tested in clinical trials in SSc, for in depths discussion of their preclinical characterization. Soluble guanylate cyclase (sGC) stimulators such as riociguat might target both vascular remodeling and tissue fibrosis. Blockade of interleukin-6 might be particularly promising for early inflammatory stages of SSc. Inhibition of serotonin receptor 2b signaling links platelet activation to tissue fibrosis. Targeting simultaneously multiple key molecules with the multityrosine kinase-inhibitor nintedanib might be a promising approach in complex fibrotic diseases such as SSc, in which many partially independent pathways are activated. Herein, we also give a state of the art overview of the current classification, clinical presentation, diagnostic approach, and treatment options of localized scleroderma. Finally, we discuss whether the novel targeted therapies currently tested in SSc could be used for localized scleroderma.

Scleroderma: Not an orphan disease any more

Scleroderma (or systemic sclerosis) is a rare disease associated with significant morbidity and mortality. Although previously thought to have a uniformly poor prognosis, the outlook has changed in recent years. We review recent insights into the pathogenesis, clinical features, assessment and management of scleroderma.

Combined effect of genetic background and gender in a mouse model of bleomycin-induced skin fibrosis

INTRODUCTION

Systemic sclerosis (SSc) is a connective tissue disorder characterised by the development of skin fibrosis. Our current understanding of the disease pathogenesis is incomplete and the study of SSc is hindered, at least partially, by a lack of animal models that fully replicate the complex state of human disease. Murine model of bleomycin-induced dermal fibrosis encapsulates important events that take place early in the disease course.

METHODS

To characterise the optimum in vivo parameters required for the successful induction of dermal fibrosis we subjected three commonly used mouse strains to repeated subcutaneous bleomycin injections. We aimed to identify the effects of genetic background and gender on the severity of skin fibrosis. We used male and female Balb/C, C57BL/6, and DBA/2 strains and assessed their susceptibility to bleomycin-induced fibrosis by measuring dermal thickness, hydroxyproline/collagen content and number of resident myofibroblasts, all of which are important indicators of the severity of skin fibrosis. All data are expressed as mean values ± SEM. The Mann-Whitney U test was used for statistical analysis with GraphPad Prism 6.04 software.

RESULTS

Dermal fibrosis was most severe in Balb/C mice compared to C57BL/6 and DBA/2 suggesting that Balb/C mice are more susceptible to bleomycin-induced fibrosis. Analysis of the effect of gender on the severity of fibrosis showed that male Balb/C, C57BL/6, DBA/2 mice had a tendency to develop more pronounced fibrosis phenotype than female mice. Of potential importance, male Balb/C mice developed the most severe fibrosis phenotype compared to male C57BL/6 and male DBA/2 as indicated by significantly increased number of dermal myofibroblasts.

CONCLUSION

Our study highlights the importance of genetic background and gender in the induction of murine dermal fibrosis. Robust and reproducible animal models of fibrosis are important research tools used in pharmacological studies which may lead to better understanding of the pathogenesis of fibrotic diseases and assist in identification of new drugs.

Lung Transplantation for Scleroderma-related Lung Disease

Lung transplantation for scleroderma-related lung disease is controversial due to extra-pulmonary organ involvement that may threaten allograft and patient survival after transplant surgery. Despite concerns, several lung transplant programs do offer lung transplantation to patients with scleroderma-related lung disease. In this review, we evaluate the scleroderma-related extra-pulmonary organ involvement that may result in poorer outcomes after lung transplantation as well as the existing evidence on survival, freedom from bronchiolitis obliterans syndrome (BOS), and other important clinical outcomes after lung transplantation. Among the nine studies reviewed, comprising 226 subjects, survival and freedom from BOS appears to be similar for subjects undergoing lung transplantation for scleroderma compared to non-scleroderma lung diseases. Although scleroderma is a systemic disease with several unique potential threats to allograft and patient survival, lung transplantation appears to be a reasonable intervention for this patient population.