Critical role for Transglutaminase 2 in scleroderma skin fibrosis and in the development of dermal sclerosis in a mouse model of scleroderma.

Objective: Scleroderma is a life-threatening autoimmune disease characterized by inflammation, tissue remodelling, and fibrosis. This study aimed to investigate the expression and function of transglutaminase 2 (TGM2) in scleroderma skin and experimentally-induced dermal fibrosis to determine its potential role and therapeutic implications.

Methods: We performed immunohistochemistry on skin sections to assess TGM2 expression and localisation, and protein biochemistry of both SSc-derived and healthy control dermal fibroblasts to assess TGM2 expression, function and ECM deposition in the presence of a TGM2 and TGFβ neutralizing antibodies and a small molecule inhibitor of the TGFβRI kinase.

Selective deletion of connective tissue growth factor attenuates experimentally-induced pulmonary fibrosis and pulmonary arterial hypertension.

Connective tissue growth factor (CTGF, CCN2) is a matricellular protein which plays key roles in normal mammalian development and in tissue homeostasis and repair. In pathological conditions, dysregulated CCN2 has been associated with cancer, cardiovascular disease, and tissue fibrosis. In this study, genetic manipulation of the CCN2 gene was employed to investigate the role of CCN2 expression in vitro and in experimentally-induced models of pulmonary fibrosis and pulmonary arterial hypertension (PAH).

Analysis of Anti-RNA Polymerase III Antibody-positive Systemic Sclerosis and Altered GPATCH2L and CTNND2 Expression in Scleroderma Renal Crisis.

Objective: Scleroderma renal crisis (SRC) is a life-threatening complication of systemic sclerosis (SSc) strongly associated with anti-RNA polymerase III antibody (ARA) autoantibodies. We investigated genetic susceptibility and altered protein expression in renal biopsy specimens in ARA-positive patients with SRC.

Methods: ARA-positive patients (n = 99) with at least 5 years' follow-up (49% with a history of SRC) were selected from a well characterized SSc cohort (n = 2254).

Limited cutaneous systemic sclerosis skin demonstrates distinct molecular subsets separated by a cardiovascular development gene expression signature.

Background: Systemic sclerosis (SSc; scleroderma) is an uncommon autoimmune rheumatic disease characterised by autoimmunity, vasculopathy and fibrosis. Gene expression profiling distinguishes scleroderma from normal skin, and can detect different subsets of disease, with potential to identify prognostic biomarkers of organ involvement or response to therapy. We have performed gene expression profiling in skin samples from patients with limited cutaneous SSc (lcSSc).

Data on CUX1 isoforms in idiopathic pulmonary fibrosis lung and systemic sclerosis skin tissue sections.

This data article contains complementary figures related to the research article entitled, "Transforming growth factor-β-induced CUX1 isoforms are associated with fibrosis in systemic sclerosis lung fibroblasts" (Ikeda et al. (2016) [2], http://dx.doi.

Transforming growth factor--induced CUX1 isoforms are associated with fibrosis in systemic sclerosis lung fibroblasts.

In the enhancer region of the human type I collagen alpha 2 () gene, we identified cis-elements for the transcription factor CUX1. However, the role of CUX1 in fibrosis remains unclear. Here we investigated the role of CUX1 in the regulation of COL1 expression and delineated the mechanisms underlying the regulation of expression by CUX1 in systemic sclerosis (SSc) lung fibroblasts.

Multiplex cytokine analysis of dermal interstitial blister fluid defines local disease mechanisms in systemic sclerosis.

Introduction: Clinical diversity in systemic sclerosis (SSc) reflects multifaceted pathogenesis and the effect of key growth factors or cytokines operating within a disease-specific microenvironment. Dermal interstitial fluid sampling offers the potential to examine local mechanisms and identify proteins expressed within lesional tissue. We used multiplex cytokine analysis to profile the inflammatory and immune activity in the lesions of SSc patients.

Failed degradation of JunB contributes to overproduction of type I collagen and development of dermal fibrosis in patients with systemic sclerosis.

Objective: The excessive deposition of extracellular matrix, including type I collagen, is a key aspect in the pathogenesis of connective tissue diseases such as systemic sclerosis (SSc; scleroderma). To further our understanding of the mechanisms governing the dysregulation of type I collagen production in SSc, we investigated the role of the activator protein 1 (AP-1) family of transcription factors in regulating COL1A2 transcription.

Methods: The expression and nuclear localization of AP-1 family members (c-Jun, JunB, JunD, Fra-1, Fra-2, and c-Fos) were examined by immunohistochemistry and Western blotting in dermal biopsy specimens and explanted skin fibroblasts from patients with diffuse cutaneous SSc and healthy controls.

Levels of target activation predict antifibrotic responses to tyrosine kinase inhibitors.

Objectives: To assess whether the discrepancy between the strong antifibrotic effects of tyrosine kinase inhibitors (TKIs) in animal models and the inconsistent results in clinical studies might be related to the activation levels of drug targets.

Methods: Skin sections of bleomycin, TSK1, Fra-2 transgenic mice, SSc patients and controls were analysed by histology and immunohistochemistry. Subgroups of mice were treated with the TKIs nilotinib or imatinib.

Endothelial injury in a transforming growth factor β-dependent mouse model of scleroderma induces pulmonary arterial hypertension.

Objective: To delineate the constitutive pulmonary vascular phenotype of the TβRIIΔk-fib mouse model of scleroderma, and to selectively induce pulmonary endothelial cell injury using vascular endothelial growth factor (VEGF) inhibition to develop a model with features characteristic of pulmonary arterial hypertension (PAH).

Methods: The TβRIIΔk-fib mouse strain expresses a kinase-deficient transforming growth factor β (TGFβ) receptor type II driven by a fibroblast-specific promoter, leading to ligand-dependent up-regulation of TGFβ signaling, and replicates key fibrotic features of scleroderma. Structural, biochemical, and functional assessments of pulmonary vessels, including in vivo hemodynamic studies, were performed before and following VEGF inhibition, which induced pulmonary endothelial cell apoptosis.

Mucosal addressin cell adhesion molecule (MAdCAM-1) expression is upregulated in the cirrhotic liver and immunolocalises to the peribiliary plexus and lymphoid aggregates.

Background: Enhanced cell expression of MAdCAM-1 is critical in tissue recruitment of lymphocytes in response to stimuli expressing the α4β7 integrin. MAdCAM-1 is well characterized in gut mucosa with emerging evidence of hepatic expression.

Aims: (i) Compare quantitative/semi-quantitatively MAdCAM-1 expression in relation to early and advanced liver diseases (ii) Define the fine structure of vascular plexuses/lymphatics in the portal tract on which MAdCAM-1 is expressed.

Focal adhesion kinase and reactive oxygen species contribute to the persistent fibrotic phenotype of lesional scleroderma fibroblasts.

Objective: Fibrotic diseases such as SSc (systemic sclerosis, scleroderma) are characterized by the abnormal presence of the myofibroblast, a specialized type of fibroblast that overexpresses the highly contractile protein α-smooth muscle actin. Myofibroblasts display excessive adhesive properties and hence exert a potent mechanical force. We aim to identify the precise contribution of adhesive signalling, which requires integrin-mediated activation of focal adhesion kinase (FAK)/src, to fibrogenic gene expression in normal and fibrotic SSc fibroblasts.

Gut fibrosis with altered colonic contractility in a mouse model of scleroderma.

Objective: Gastrointestinal involvement occurs in up to 90% of patients with SSc. Animal models of SSc mimic some of the pathophysiological disease processes of SSc. The transgenic (TG) mouse strain TβRIIΔk-fib is characterized by ligand-dependent up-regulation of TGF-β signalling and has been shown to develop skin fibrosis, lung fibrosis and diminished aortic ring contractility and adventitial fibrosis.

Clinical and pathological significance of interleukin 6 overexpression in systemic sclerosis.

Objective: To determine the potential clinical and pathological significance of altered expression of interleukin 6 (IL-6) in systemic sclerosis (SSc).

Methods: Serum IL-6 and soluble IL-6 receptor levels were measured in patients with SSc (n=68) and healthy controls (n=15). Associations between serum IL-6 level and C reactive protein, platelet count and key clinical outcomes in SSc were explored.

An essential role for resident fibroblasts in experimental lung fibrosis is defined by lineage-specific deletion of high-affinity type II transforming growth factor β receptor.

Rationale: Fibrotic response to lung injury depends on development of a fibrogenic population of myofibroblasts. The importance of resident interstitial fibroblasts and role of transforming growth factor β (TGFβ) in this process is unclear.

Objectives: To define the importance of TGFβ signaling in resident lung fibroblasts in the development of experimental pulmonary fibrosis.

Systemic vasculopathy with altered vasoreactivity in a transgenic mouse model of scleroderma.

Introduction: Vasculopathy, including altered vasoreactivity and abnormal large vessel biomechanics, is a hallmark of systemic sclerosis (SSc). However, the pathogenic link with other aspects of the disease is less clear. To assess the potential role of transforming growth factor beta (TGF-beta) overactivity in driving these cardiovascular abnormalities, we studied a novel transgenic mouse model characterized by ligand-dependent activation of TGF-beta signaling in fibroblasts.

Expression of the HER-1-4 family of receptor tyrosine kinases in neuroendocrine tumours.

The type I receptor tyrosine kinase family comprises four homologous members: Epidermal growth factor receptor (EGFR), HER-2, HER-3 and HER-4. Studies have shown that EGFR and HER-2 play a critical role in oncogenesis. In this study we sought to determine the pattern of expression and the prognostic significance of EGFR, HER-2, HER-3 and HER-4 in a variety of neuroendocrine tumours using immunohistochemistry.

Lymphatic and blood vessels in scleroderma skin, a morphometric analysis.

Vascular involvement is frequent in systemic sclerosis, but the role of the lymphatic vasculature is poorly known. Our aim was to evaluate lymphatic vessels in systemic sclerosis skin lesions. We studied skin forearm biopsies of 9 patients with systemic sclerosis and 7 age-matched controls.

Pivotal role of connective tissue growth factor in lung fibrosis: MAPK-dependent transcriptional activation of type I collagen.

Objective: Connective tissue growth factor (CTGF; CCN2) is overexpressed in systemic sclerosis (SSc) and has been hypothesized to be a key mediator of the pulmonary fibrosis frequently observed in this disease. CTGF is induced by transforming growth factor beta (TGFbeta) and is a mediator of some profibrotic effects of TGFbeta in vitro. This study was undertaken to investigate the role of CTGF in enhanced expression of type I collagen in bleomycin-induced lung fibrosis, and to delineate the mechanisms of action underlying the effects of CTGF on Col1a2 (collagen gene type I alpha2) in this mouse model and in human pulmonary fibroblasts.

Cross-talk between MCP-3 and TGFbeta promotes fibroblast collagen biosynthesis.

Recent studies have demonstrated upregulation of monocyte chemoattractant protein-3 (MCP-3/CCL7) in fibrosis and have suggested that in addition to a major role in regulating leucocyte recruitment this chemokine may also promote extracellular matrix (ECM) overproduction by fibroblasts. In the present study we explore interplay between MCP-3 and transforming growth factor beta (TGFbeta), a potent profibrotic cytokine. We demonstrate that MCP-3 promotes activation of TGFbeta signalling pathways leading to increased type I collagen secretion.

Loss of protein kinase Cepsilon results in impaired cutaneous wound closure and myofibroblast function.

Cutaneous wound repair requires the de novo induction of a specialized form of fibroblast, the alpha-smooth muscle actin (alpha-SMA)-expressing myofibroblast, which migrates into the wound where it adheres to and contracts extracellular matrix (ECM), resulting in wound closure. Persistence of the myofibroblast results in scarring and fibrotic disease. In this report, we show that, compared with wild-type littermates, PKCepsilon-/- mice display delayed impaired cutaneous wound closure and a reduction in myofibroblasts.

Inducible lineage-specific deletion of TbetaRII in fibroblasts defines a pivotal regulatory role during adult skin wound healing.

Previous attempts to delete type II TGFbeta receptor (TbetaRII) in fibroblasts have precluded examination of adult mice due to early mortality. We have selectively deleted TbetaRII postnatally in differentiated connective tissue fibroblasts using an inducible Cre-Lox strategy. Tamoxifen-dependent Cre recombinase linked to a fibroblast-specific regulatory sequence from the proalpha2(I)collagen gene permitted deletion of floxed TbetaRII alleles.

Fibroblast-specific perturbation of transforming growth factor beta signaling provides insight into potential pathogenic mechanisms of scleroderma-associated lung fibrosis: exaggerated response to alveolar epithelial injury in a novel mouse model.

Objective: To explore increased susceptibility to fibrosis following experimental injury to alveolar epithelial cells (AECs) in a novel transgenic mouse model of scleroderma with fibroblast-specific perturbation of transforming growth factor beta (TGFbeta) signaling (TbetaRIIDeltak-fib mice).

Methods: Wild-type (WT) and transgenic mice were injured with intratracheally administered saline or bleomycin, and the lungs were harvested for biochemical, histologic, and electron microscopic analysis.

Results: Electron microscopy revealed AEC abnormalities in the lungs of untreated transgenic mice and bleomycin-treated WT mice; the lungs of transgenic mice treated with bleomycin showed severe epithelial damage.