Brief Report: Association of Elevated Adipsin Levels With Pulmonary Arterial Hypertension in Systemic Sclerosis.

OBJECTIVE: Adipose tissues secrete adipokines, peptides with potent effects modulating fibrosis, inflammation, and vascular homeostasis. Dysregulated adipose tissue biology and adipokine balance have recently been implicated in systemic sclerosis (SSc). This study was undertaken to determine whether altered circulating adipokine levels correlate with SSc disease subsets or clinical manifestations. METHODS: Multiplex assays were used to measure circulating adipokine levels in 198 patients with SSc and 33 healthy controls. Data were evaluated for correlations between serum adipokine levels and demographic and clinical features, including pulmonary arterial hypertension (PAH). To assess the relevance of adipsin, an adipokine involved in complement pathway activation, in SSc, we analyzed publicly available genetic and transcriptomic data. RESULTS: Levels of adiponectin and adipsin differed significantly between controls and patients. Adipsin was significantly elevated in patients with limited cutaneous SSc (odds ratio [OR] 28.3 [95% confidence interval (95% CI) 7.0-113.8]; P < 0.0001), and its levels were associated with serum autoantibody status, pulmonary function and cardiovascular parameters, and PAH (OR 3.3 [95% CI 1.3-8.7]; P = 0.02). Elevated adipsin was more strongly associated with PAH than B-type natriuretic peptide was. Moreover, in SSc patients, adipsin gene single-nucleotide polymorphisms were associated with PAH. Transcriptome data set analysis demonstrated elevated adipsin expression in patients with SSc-related PAH. CONCLUSION: We identify adipsin as a novel adipose tissue-derived marker of SSc-related PAH. Circulating adipsin levels might serve as predictive biomarkers in SSc. Mechanistically, adipsin might represent a pathogenic link between adipocyte dysfunction and complement pathway activation and play an important role in the pathogenesis of SSc-related PAH.

Comparison of change in end tidal carbon dioxide after three minutes of step exercise between systemic sclerosis patients with and without pulmonary hypertension.

OBJECTIVES: Pulmonary hypertension (PH) is an important cause of morbidity and mortality in patients with SSc. The submaximal heart and pulmonary evaluation (step test) is a non-invasive, submaximal stress test that could be used to identify SSc patients with PH. Our aims were to determine whether change in end tidal carbon dioxide ([Formula: see text]) from rest to end-exercise, and the minute ventilation to carbon dioxide production ratio ([Formula: see text]), both as measured by the step test, differ between SSc patients with and without PH. We also examined differences in validated self-report questionnaires and potential PH biomarkers between SSc patients with and without PH. METHODS: We performed a cross-sectional study of 27 patients with limited or dcSSc who underwent a right heart catheterization within 24 months prior to study entry. The study visit consisted of questionnaire completion; history; physical examination; step test performance; and phlebotomy. [Formula: see text], [Formula: see text], self-report data and biomarkers were compared between patients with and without PH. RESULTS: SSc patients with PH had a statistically significantly lower median (interquartile range) [Formula: see text] than SSc patients without PH [-2.1 (-5.1 to 0.7) vs 1.2 (-0.7 to 5.4) mmHg, P = 0.035], and a statistically significantly higher median (interquartile range) [Formula: see text] [53.4 (39-64.1) vs 36.4 (31.9-41.1), P = 0.035]. There were no statistically significant differences in self-report data or biomarkers between groups. CONCLUSION: [Formula: see text] and [Formula: see text] as measured by the step test are statistically significantly different between SSc patients with and without PH. [Formula: see text] and [Formula: see text] may be useful screening tools for PH in the SSc population.

Platelets Induce Thymic Stromal Lymphopoietin Production by Endothelial Cells: Contribution to Fibrosis in Human Systemic Sclerosis.

OBJECTIVE: To investigate the relationship between vascular damage and fibrosis in systemic sclerosis (SSc) by testing the hypothesis that platelets contribute to skin fibrosis via the activation of human dermal microvascular endothelial cells (HDMECs) and subsequent production of profibrotic mediators. METHODS: A total of 203 SSc patients and 30 healthy donors were prospectively enrolled between 2012 and 2015 at the University Hospital of Bordeaux. Immunohistochemistry and immunofluorescence analyses were performed on skin biopsy sections from 18 SSc patients and 5 healthy donors. Serum thymic stromal lymphopoietin (TSLP) levels were measured by enzyme-linked immunosorbent assay in the entire cohort. HDMECs and fibroblasts were purified from biopsy sections. Extracellular matrix production by cultured fibroblasts was assessed by real-time quantitative polymerase chain reaction. RESULTS: Serum TSLP levels were significantly increased in SSc patients compared to healthy donors (P < 0.0001) and were associated with a higher frequency of vasculopathy (P = 0.02). The proportion of TSLP-positive dermal cells was increased in the skin of SSc patients compared with healthy donors (P < 0.0001) and was correlated with fibrosis (modified Rodnan skin thickness score) (r = 0.6146, P = 0.0001). In SSc dermis, TSLP was mainly expressed by CD31-positive endothelial cells. In vitro, activated platelets induced TSLP production by HDMECs in an interleukin-1ß-dependent manner. SSc fibroblasts responded differently according to their original TSLP environment. CONCLUSION: Taken together, these results identify HDMECs as contributors to TSLP production in SSc and suggest a potential mechanism by which platelets may profoundly affect the fibrotic process in SSc.

Enrichment of Scleroderma Vascular Disease-Associated Autoantigens in Endothelial Lineage Cells.

OBJECTIVE: Scleroderma patients with autoantibodies to CENPs and/or interferon-inducible protein 16 (IFI-16) are at increased risk of severe vascular complications. This study was undertaken to determine whether these autoantigens are enriched in cells of the vasculature. METHODS: Successive stages of embryoid bodies (EBs) as well as vascular progenitors were used to evaluate the expression of scleroderma autoantigens IFI-16 and CENP by immunoblotting. CD31 was included to mark early blood vessels. IFI-16 and CD31 expression were defined in paraffin-embedded skin sections from scleroderma patients and from healthy controls. IFI-16 expression was determined by flow cytometric analysis in circulating endothelial cells (CECs) and circulating hematopoietic progenitor cells. RESULTS: Expression of CENP-A, IFI-16, and CD31 was enriched in EBs on days 10 and 12 of differentiation, and particularly in cultures enriched in vascular progenitors (IFI-16, CD31, and CENPs A and B). This pattern was distinct from that of comparator autoantigens. Immunohistochemical staining of paraffin-embedded skin sections showed enrichment of IFI-16 in CD31-positive vascular endothelial cells in biopsy specimens from scleroderma patients and normal controls. Flow cytometric analysis revealed IFI-16 expression in circulating hematopoietic progenitor cells but minimal expression in CECs. CONCLUSION: Our findings indicate that expression of the scleroderma autoantigens IFI-16 and CENPs, which are associated with severe vascular disease, is increased in vascular progenitors and mature endothelial cells. High level, lineage-enriched expression of autoantigens may explain the striking association between clinical phenotypes and the immune targeting of specific autoantigens.

CD81 and CD48 show different expression on blood eosinophils in systemic sclerosis: new markers for disease and pulmonary inflammation?

OBJECTIVES: In systemic sclerosis (SSc)-related interstitial lung disease (ILD), elevated eosinophil counts in bronchoalveolar lavage are associated with a worse outcome. We hypothesized that eosinophils may be activated in the peripheral circulation, thereby increasing their recruitment to affected tissues and contributing to inflammation and fibrosis. The aim of this study was to characterize the blood eosinophils in SSc patients. METHOD: Expression levels of surface markers CD11b, CD44, CD48, CD54, CD69, CD81, and HLA-DR on CD16(low)CD9(high)-expressing eosinophils were measured by flow cytometry in whole blood from SSc patients (n = 32) and controls (n = 11). RESULTS: Expression levels of CD54, CD69, and HLA-DR were undetectable in all groups. CD44 and CD11b expression levels were similar between groups. CD81 expression was lower in patients compared to controls independent of disease duration (p = 0.001). CD48 expression was increased in patients with a short disease duration (< 2 years) compared to both controls (p = 0.042) and patients with longer disease duration (≥ 2 years; p = 0.027). In patients with short disease duration, increased CD48 expression was associated with alveolar inflammation as measured by an increased concentration of alveolar nitric oxide (r = 0.76, p = 0.003). CONCLUSIONS: Blood eosinophils change phenotype during disease evolution in SSc, and CD48 expression may be used as a biomarker for pulmonary inflammation.

Resolution of Skin Fibrosis by Neutralization of the Antifibrinolytic Function of Plasminogen Activator Inhibitor 1.

OBJECTIVE: Systemic sclerosis (SSc) is a fibrotic disease characterized by an obliterative vasculopathy with thrombosis and impairment of the coagulation-fibrinolysis balance. Plasminogen activator inhibitor 1 (PAI-1) is the major inhibitor of profibrinolytic plasminogen activators (PAs). This study was undertaken to evaluate the contribution of PAI-1 to SSc pathology in the skin. METHODS: PAI-1 was evaluated in skin from patients with diffuse SSc (dSSc) and those with limited SSc (lSSc) by immunohistochemistry. The contribution of PAI-1 to SSc pathology was tested in vivo in murine graft-versus-host disease (GVHD) and bleomycin models of progressive skin fibrosis and in vitro in dermal human microvascular endothelial cells (HMVECs) using a monoclonal antibody that selectively prevents the binding of PAI-1 to PA. RESULTS: Skin from patients with dSSc and those with lSSc showed increased PAI-1 levels in the epidermis and microvessel endothelium. PAI-1 neutralization in the GVHD model led to a dramatic, dose-dependent improvement in clinical skin score, concomitant with vasculopathy resolution, including a reduction in fibrinolysis regulators and vascular injury markers, as well as reduced inflammation. Resolution of vasculopathy and inflammation was associated with resolution of skin fibrosis, as assessed by reduction in collagen content and expression of key profibrotic mediators, including transforming growth factor ß1 and tissue inhibitor of metalloproteinases 1. Similar to the GVHD model, PAI-1 neutralization reduced dermal inflammation and fibrosis in the bleomycin model. PAI-1 neutralization stimulated plasmin-mediated metalloproteinase 1 activation in dermal HMVECs. CONCLUSION: Our findings indicate that neutralization of the antifibrinolytic function of PAI-1 resolves skin fibrosis by limiting the extent of initial vascular injury and connective tissue inflammation. These data suggest that PAI-1 represents an important checkpoint in disease pathology in human SSc.

Genome-wide DNA methylation analysis in dermal fibroblasts from patients with diffuse and limited systemic sclerosis reveals common and subset-specific DNA methylation aberrancies.

BACKGROUND: The aetiology of systemic sclerosis (SSc) is not clear, but there is an emerging evidence of gene-specific epigenetic dysregulation in the pathogenesis of SSc. METHODS: We performed a genome-wide DNA methylation study in dermal fibroblasts in six diffuse cutaneous SSc (dSSc) patients, six limited cutaneous SSc (lSSc) patients compared with 12 age-matched, sex-matched and ethnicity-matched healthy controls. Cytosine methylation was quantified in more than 485 000 methylation sites across the genome. Differentially methylated CpG sites between patients and controls with a fold difference ≥1.2 were identified. Quantitative real-time RT-PCR was performed to assess correlation between DNA methylation changes and gene expression levels. RESULTS: We identified 2710 and 1021 differentially methylated CpG sites in dSSc and lSSc, respectively. Of the differentially methylated sites, 61% in dSSc and 90% in lSSc were hypomethylated. There were only 203 CpG sites differentially methylated in both dSSc and lSSc, representing 118 hypomethylated and 6 hypermethylated genes. Common hypomethylated genes include ITGA9, encoding an α integrin. Other relevant genes such as ADAM12, COL23A1, COL4A2 and MYO1E, and transcription factors genes RUNX1, RUNX2 and RUNX3 were also hypomethylated in both dSSc and lSSc. Pathway analysis of differentially methylated genes in both dSSc and lSSc revealed enrichment of genes involved in extracellular matrix-receptor interaction and focal adhesion. We demonstrate significant correlation between DNA methylation status and gene expression in the majority of genes evaluated. CONCLUSIONS: Our data highlight common and subset-specific aberrancies in dSSc and lSSc fibroblasts at the epigenomic levels and identify novel candidate genes in SSc.

A three-year follow-up study of the development of joint contractures in 131 patients with systemic sclerosis.

OBJECTIVES: To analyse the correlation between the number of joint-contractures and other major clinical findings in a follow-up study of 131 patients with systemic sclerosis (SSc). METHODS: The range of motion of joints (ROM), HAQ-DI, and the major clinical characteristics were assessed. RESULTS: A high frequency of contractures (ROM<75% of the normal) were present at baseline in small joints of the hand (82%), wrists (75%), and shoulders (50%). ROM of the dominant side hand was significantly more decreased compared to the non-dominant side. The number of the upper extremity contractures correlated positively with ESR (p<0.01), CRP (p<0.01), HAQ-DI (p<0.01), and negatively with forced vital capacity (FVC) (p<0.05). The number of contractures was not significantly different in cases with early (≤ 4 years) and late disease duration in both the limited and diffuse subgroups. During the three-year follow-up period, an increase in the number of joint contractures (ROM<75%) was associated with an increase of ESR, modified Rodnan's skin score, and the European Scleroderma Study Group Activity Index by multiple linear regression analysis. Univariate analysis over a six-year period demonstrated poor outcome in patients with more than ten contractures, or more than four contractures of unilateral hand-joints. CONCLUSIONS: Contractures predominantly develop during the early years following disease onset in both SSc subgroups. Inflammation and skin-involvement are significant contributing factors for the development of contractures. The dominant hand may be more pronouncedly impaired compared to the non-dominant side. A high number of joint-contractures might be an unfavourable prognostic factor in SSc.

Skin progenitor cells contribute to bleomycin-induced skin fibrosis.

OBJECTIVE: The origin of the cells that contribute to skin fibrosis is unclear. We undertook the present study to assess the contribution of Sox2-expressing skin progenitor cells to bleomycin-induced scleroderma. METHODS: Scleroderma was induced, by bleomycin administration, in wild-type mice and in mice in which CCN2 was deleted from Sox2-expressing cells. Lineage tracing analysis was performed to assess whether cells expressing Sox2 are recruited to fibrotic lesions in response to bleomycin-induced scleroderma. RESULTS: In response to bleomycin, Sox2-positive/α-smooth muscle actin-positive cells were recruited to fibrotic tissue. CCN2-conditional knockout mice in which CCN2 was deleted from Sox2-expressing cells exhibited resistance to bleomycin-induced skin fibrosis. Collectively, these results indicate that CCN2 is required for the recruitment of progenitor cells and that CCN2-expressing progenitor cells are essential for bleomycin-induced skin fibrosis. Lineage tracing analysis using mice in which a tamoxifen-dependent Cre recombinase was expressed under the control of the Sox2 promoter confirmed that progenitor cells were recruited to the fibrotic lesion in response to bleomycin, and that this did not occur in CCN2-knockout mice. The ability of serum to induce α-smooth muscle actin expression in skin progenitor cells required the presence of CCN2. CONCLUSION: Sox2-positive skin progenitor cells are required in order for bleomycin-induced skin fibrosis to occur, and CCN2 is required for the recruitment of these cells to the fibrotic lesion. Targeting stem cell recruitment or CCN2 may therefore represent a useful therapeutic approach in combating fibrotic skin disease.

Decreased interleukin-20 expression in scleroderma skin contributes to cutaneous fibrosis.

OBJECTIVE: To clarify the role of interleukin-20 (IL-20) in the regulatory mechanism of extracellular matrix expression and to determine the contribution of IL-20 to the phenotype of systemic sclerosis (SSc). METHODS: Protein and messenger RNA (mRNA) levels of collagen, Fli-1, IL-20, and IL-20 receptor (IL-20R) were analyzed using polymerase chain reaction (PCR) array, immunoblotting, immunohistochemical staining, enzyme-linked immunosorbent assay, and real-time PCR. RESULTS: PCR array revealed that IL-20 decreased gene expression of α2(I) collagen (0.03-fold), Smad3 (0.02-fold), and endoglin (0.05-fold) in cultured normal dermal fibroblasts. Fli-1 protein expression was induced by IL-20 (~2-fold). The inhibition of collagen by IL-20, the induction of Fli-1 by IL-20, and the reduction of Smad3 and endoglin by IL-20 were also observed in SSc fibroblasts. Serum IL-20 levels were reduced only slightly in SSc patients but were significantly decreased in patients with scleroderma spectrum disorders (the prodromal stage of SSc) compared with those in normal subjects (111.3 pg/ml versus 180.4 pg/ml; P < 0.05). On the other hand, IL-20 mRNA expression in SSc skin was decreased compared with that in normal skin (P < 0.05), which may result in the induction of collagen synthesis in SSc dermal fibroblasts. IL-20R was expressed in normal and SSc fibroblasts. Moreover, IL-20 supplementation by injection into the skin reversed skin fibrosis induced by bleomycin in mice (~0.5-fold). CONCLUSION: IL-20 reduces basal collagen transcription via Fli-1 induction, while down-regulation of Smad3 and endoglin may cancel the effect of transforming growth factor ß in SSc fibroblasts. To confirm the therapeutic value of IL-20 and IL-20R, their function and expression in vivo should be further studied.

Alteration of circulating miRNAs in SSc: miR-30b regulates the expression of PDGF receptor ß.

OBJECTIVE: Although several miRNAs have been shown to regulate autoimmune pathogenesis by affecting lymphocyte function, the roles of miRNAs in the pathogenesis of SSc remain unclear. Therefore the purpose of this study was to identify miRNAs that play a role in the pathogenesis of SSc by quantitative PCR screening of serum miRNAs. METHODS: Ninety-five miRNAs that were predicted to target SSc-related genes [IL-4, TGF-ß, CTGF, PDGF-B, PDGF receptor (PDGFR) α/ß and COL1A2) by in silico analyses were selected. The expression of these miRNAs in sera of SSc patients and healthy controls was measured by quantitative PCR. Involvement of miR-30b, which was most strongly down-regulated in SSc patients, in the regulation of PDGFR-ß expression was examined by transfection experiments and 3'-untranslated region (3'-UTR) target luciferase assays. The expression of miR-30b in skin was evaluated in a bleomycin-induced dermal fibrosis model in mice and in SSc patients. RESULTS: Nineteen of 95 miRNAs were significantly decreased in the sera of SSc patients. Among them, miR-30b was most strongly down-regulated in SSc patients (P = 0.00006) and the levels of miR-30b were inversely correlated with modified Rodnan skin scores. Transfection of a miR-30b mimic repressed PDGFR-ß expression in dermal fibroblasts and the activity of a luciferase reporter containing 3'-UTR of PDGFR-ß. Moreover, the expression of miR-30b was down-regulated in bleomycin-treated sclerotic skin and in affected skin in SSc patients. CONCLUSION: Down-regulation of miR-30b might be involved in the pathogenesis of SSc.

Adiponectin expression is decreased in the involved skin and sera of diffuse cutaneous scleroderma patients.

In this study, we determined the adiponectin expression in the serum and lesional skin of patients with scleroderma (SSc). Serum adiponectin concentrations were measured in 32 patients with SSc, 10 patients with SLE, 12 patients with dermatomyositis patients and 13 healthy subjects with specific enzyme-linked immunosorbent assays. Adiponectin mRNA was determined in skin tissues of five patients with diffuse cutaneous SSc (dcSSc), seven patients with limited cutaneous SSc (lcSSc) and seven healthy subjects with real-time polymerase chain reaction. There was a significant reduction in serum adiponectin levels in patients with dcSSc. SSc patients with decreased serum adiponectin levels had higher total skin thickness score and higher incidence of pulmonary fibrosis. Adiponectin mRNA levels in skin tissues from patients with dcSSc were also reduced. Serum adiponectin levels may be a useful biomarker for fibrotic condition in patients with SSc. Clarifying the role of adiponectin in collagen diseases may lead to further understanding of the pathogenesis and new therapeutic approach.

Mast cells are a source of transforming growth factor ß in systemic sclerosis.

OBJECTIVE: To describe the cellular source of transforming growth factor ß (TGFß) in the dermis of patients with systemic sclerosis (SSc). METHODS: We performed electron microscopy (EM) with immunogold labeling on skin biopsy specimens from 7 patients with SSc and 3 healthy control subjects. For TGFß quantification, the numbers of gold particles per square micron were calculated. The origin of mast cells was confirmed and quantified by toluidine blue staining and light microscopy. Degranulation was assessed on toluidine blue-stained sections and on EM images. RESULTS: In all patients, active TGFß was observed uniquely in mast cell vesicles, some of which were released into the extracellular space. Patients with progressive SSc and a more recent onset of non-Raynaud's phenomenon symptoms had higher numbers of mast cells and gold particles per mast cell. Mast cells from healthy control subjects also contained active TGFß but, in contrast to SSc samples, showed a resting character with no or low-level degranulation and uniformly dense osmiophilic vesicles. CONCLUSION: Degranulation of skin mast cells can be an important mechanism of TGFß secretion in SSc.

Low circulating level of CD133+KDR+cells in patients with systemic sclerosis.

BACKGROUND: Results of previous studies on the level of circulating endothelial progenitor cells (EPCs), which are involved in vascular repair, in scleroderma (SSc) patients have been controversial. OBJECTIVES: To enumerate circulating EPC subsets and to examine their relation with endothelial dysfunction, biochemical markers of endothelial injury and vascular outcome in SSc patients. METHODS: Enumeration of circulating CD34+KDR+ and CD133+ KDR+EPCs was performed by flow cytometry. Endothelium-dependent vasodilation was evaluated by changes in flow-mediated dilation (FMD%) in the brachial artery. Serum level of vascular endothelial growth factor (VEGF) was measured by enzyme linked immunosorbent assay. RESULTS: SSc patients (n=52) were found to have significantly lower CD133+KDR+EPCs (3.0 vs. 7.0/µl, p<0.001) as well as FMD% (4.8% vs. 7.8%, p<0.001) compared with age and sex-matched controls (n=52). Among patients who had no concomitant cardiovascular risk factors (n=28), CD133+KDR+ EPC level was significantly lower than controls (3.8 vs. 7.3/µl, p=0.001) and correlated modestly with FMD% (r=0.29, p=0.03). Disease duration was the only determining factor identified for circulating CD133+KDR+ EPCs (p=0.03) by logistic regression analysis. Levels of serum VEGF (p=0.92) and KDR expression were not different between patients who had early and intermediate/late disease. Circulating CD34+KDR+ EPCs was not different between SSc patients and controls and did not correlate with any clinical or biochemical parameter. CONCLUSIONS: Lower circulating CD133 +KDR+ EPC subset was found in SSc patients and correlated with impaired endothelium-dependent vasodilation in patients without cardiovascular risk factors suggesting a potential role of deficient EPC recruitment contributing to endothelial dysfunction in this disease.

The tumour necrosis factor-related apoptosis-inducing ligand-osteoprotegerin system in limited systemic sclerosis: a new disease marker?

OBJECTIVE: To investigate the role of the TNF-related apoptosis-inducing ligand-osteoprotegerin (TRAIL-OPG) system in the pathogenesis of limited SSc (lSSc). METHODS: Circulating levels of TRAIL and of its soluble receptor OPG were measured by ELISA in serum samples obtained from 50 lSSc patients and 50 healthy controls. RESULTS: TRAIL serum levels in lSSc patients were similar to those of healthy controls, whereas the OPG serum levels were significantly increased (P < 0.0001). According to different subgroups of lSSc patients, TRAIL was not statistically different between each group and healthy controls; concerning OPG, the statistically different value was also maintained when comparing each single lSSc group with the whole control population. CONCLUSIONS: OPG serum levels, but not TRAIL, are elevated in lSSc patients. Since OPG binding to TRAIL inhibits TRAIL-TRAIL receptor interaction, the relative concentrations of these two molecules in the local micro-environment has to be considered. In this setting, OPG increase in lSSc patients may produce a detrimental effect by counteracting the vasoprotective activity of TRAIL. The TRAIL : OPG ratio and their relative levels of expression in lSSc patients should be taken into consideration as a possible novel marker of vascular damage.

Is scleroderma a vasculopathy?

Described as an autoimmune collagen vascular disease, the most striking feature of scleroderma may be a systemic vasculopathy. This vasculopathy includes characteristic noninflammatory macrovascular and microvascular changes with dramatic and possibly occlusive formation of a thickened neointima. Scleroderma vessels also have an unusual endothelial phenotype, with loss of normal markers including vascular endothelial (VE)-cadherin. These endothelial cells express type 1 interferon and regulator of G protein signaling 5 (RGS5), two molecules associated with vascular rarefaction. These genes may be important because tissue is hypoxic with high levels of vascular endothelial growth factor (VEGF), especially early in the disease. The combination of VEGF and rarefaction is not necessarily paradoxical. VEGF-mediated angiogenesis creates labile vessels that may not survive unless the vessel acquires a smooth muscle coat. The combination of interferon and RGS5 is consistent with an antiangiogenic phenotype. We offer a hypothesis that places vascular injury at the center of this disease and also suggest possible clinical approaches for arresting and/or reversing the disease.

Cartilage oligomeric matrix protein expression in systemic sclerosis reveals heterogeneity of dermal fibroblast responses to transforming growth factor beta.

OBJECTIVE: Cartilage oligomeric matrix protein (COMP) accumulates in systemic sclerosis (SSc) skin and is upregulated by transforming growth factor (TGF)beta. To further characterise the response to TGFbeta in SSc, we investigated TGFbeta1 and COMP expression and myofibroblast staining in SSc skin. METHODS: Skin biopsies from patients with diffuse cutaneous SSc (dSSc), limited cutaneous SSc (lSSc) and healthy controls were evaluated for COMP mRNA expression using real-time PCR. COMP, alpha-smooth muscle actin (SMA) and TGFbeta were assessed in skin sections and in cultured fibroblasts by immunohistochemistry. Clinical disease status was assessed by the modified Rodnan skin score (mRSS). RESULTS: Myofibroblasts expressing SMA and COMP were found coexpressed in many cells in dSSc dermis, but each also stained distinct cells in the dermis. Cultured SSc dermal fibroblasts also showed heterogeneity for COMP and SMA expression, with cells expressing SMA, COMP, both or neither. TGFbeta treatment increased COMP and SMA-expressing cells. COMP mRNA expression in lesional skin from patients with dSSc correlated with the mRSS and TGFbeta1 staining. CONCLUSION: These findings suggest that TGFbeta upregulation of COMP and/or SMA expression in subpopulations of fibroblasts contributes to different pathways of fibrosis and that multiple TGFbeta regulated genes may serve as biomarkers for the degree of SSc skin involvement.

Molecular subsets in the gene expression signatures of scleroderma skin.

BACKGROUND: Scleroderma is a clinically heterogeneous disease with a complex phenotype. The disease is characterized by vascular dysfunction, tissue fibrosis, internal organ dysfunction, and immune dysfunction resulting in autoantibody production. METHODOLOGY AND FINDINGS: We analyzed the genome-wide patterns of gene expression with DNA microarrays in skin biopsies from distinct scleroderma subsets including 17 patients with systemic sclerosis (SSc) with diffuse scleroderma (dSSc), 7 patients with SSc with limited scleroderma (lSSc), 3 patients with morphea, and 6 healthy controls. 61 skin biopsies were analyzed in a total of 75 microarray hybridizations. Analysis by hierarchical clustering demonstrates nearly identical patterns of gene expression in 17 out of 22 of the forearm and back skin pairs of SSc patients. Using this property of the gene expression, we selected a set of 'intrinsic' genes and analyzed the inherent data-driven groupings. Distinct patterns of gene expression separate patients with dSSc from those with lSSc and both are easily distinguished from normal controls. Our data show three distinct patient groups among the patients with dSSc and two groups among patients with lSSc. Each group can be distinguished by unique gene expression signatures indicative of proliferating cells, immune infiltrates and a fibrotic program. The intrinsic groups are statistically significant (p<0.001) and each has been mapped to clinical covariates of modified Rodnan skin score, interstitial lung disease, gastrointestinal involvement, digital ulcers, Raynaud's phenomenon and disease duration. We report a 177-gene signature that is associated with severity of skin disease in dSSc. CONCLUSIONS AND SIGNIFICANCE: Genome-wide gene expression profiling of skin biopsies demonstrates that the heterogeneity in scleroderma can be measured quantitatively with DNA microarrays. The diversity in gene expression demonstrates multiple distinct gene expression programs in the skin of patients with scleroderma.

Association of psoriasin (S100A7) with clinical manifestations of systemic sclerosis: is its presence in whole saliva a potential predictor of pulmonary involvement?

OBJECTIVE: To evaluate psoriasin (S100A7) expression in whole saliva (WS) of patients with diffuse systemic sclerosis (dSSc) and limited SSc (lSSc), and to correlate its presence with the different clinical manifestations of the disease. METHODS: Forty-four patients with limited or diffuse SSc were enrolled for study. WS proteins were separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and psoriasin was identified by Western blot analysis using a specific polyclonal antibody. Patients with other rheumatic diseases with and without lung involvement were enrolled as pathological controls. Statistical analysis was performed to correlate each clinical manifestation with the presence of psoriasin. RESULTS: Three bands of 12, 24, and 50 kDa corresponding to monomeric and dimeric/multimeric forms of psoriasin were evidenced by immunoblot analysis in WS of 31 out of 44 patients with SSc (70.4%). In the other 13 WS samples, the 12 kDa band was totally absent, while the dimeric and multimeric bands were expressed at optical intensity (OD) levels comparable to the other samples. From a clinical point of view, the presence of 12 kDa monomeric psoriasin was significantly associated with SSc pulmonary involvement and with anti-Scl-70 antibody positivity. No control showed the psoriasin 12 kDa band. CONCLUSION: Our results identified salivary 12 kDa psoriasin as a potential predictor of pulmonary involvement in SSc. Thus, a psoriasin assay might be considered as a rapid, noninvasive, useful salivary biomarker for the detection of pulmonary involvement in SSc.

Relaxin receptors--new drug targets for multiple disease states.

Relaxin was discovered more than 75 years prior to the identification of the receptors that mediate its actions. There has been a slow emergence in understanding the role of relaxin, with it being denoted initially as a hormone of pregnancy due to its observed effects to relax pubic ligaments and soften the cervix of guinea pigs to facilitate parturition. However, many other physiological roles have been identified for relaxin, including cardiovascular and neuropeptide functions and an ability to induce the matrix metalloproteinases, so it is clear that relaxin is not exclusively a hormone of pregnancy but has a much wider role in vivo. The recent de-orphanisation of four receptors LGR7, LGR8, GPCR135 (SALPR) and GPCR142 (GPR100) that respond to and bind at least one of the three forms of relaxin identified to date, allows dissection of this system to determine the precise role of each receptor and enable the identification of new targets for treatment of numerous disease states. Relaxin has the potential to be useful for the treatment of scleroderma, fibrosis, in orthodontics and to facilitate embryo implantation in humans. Relaxin antagonists may act as contraceptives or prevent the development of breast cancer metastases. Recent research has added considerable knowledge to the signalling pathways activated by relaxin, which will aid our understanding of how relaxin produces its effects. The focus of this review is to bring together recent developments in the relaxin receptor field and to highlight their potential as drug targets.