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Several studies have suggested that Wnts might contribute to skin fibrosis in systemic sclerosis (SSc) by affecting the differentiation of pluripotent dermal cells. We tested C-82, a therapeutic that inhibits canonical Wnt signaling by blocking the interaction of cAMP Response Element-Binding Protein with β-Catenin and inhibiting Wnt-activated genes. We utilized previously unreported trial design, formulating C-82 for topical application and conducting a placebo controlled, double-blinded clinical trial in which patients with diffuse cutaneous SSc were treated with C-82 or placebo on opposite forearms. C-82 compared to placebo treated forearms did not show any clinical effect. Skin biopsies performed before and after treatment showed a very weak trend toward improvement in the C-82 treated skin of biomarkers of local skin disease, THBS1 and COMP. However, on microarray analysis C-82 treatment strongly upregulated two clusters of genes that correlate negatively with the severity of SSc skin disease. These clusters are highly associated with metabolism and one gene, PLIN2, expressed only by sebocytes and subcutaneous fat cells. These changes in gene expression strongly support a role for Wnts in differentiation of pluripotent cells into profibrotic fibroblasts, and the potential for C-82 with longer treatment to promote fat regeneration in SSc skin.

Systemic sclerosis (SSc) is a multi-organ fibrotic disease with few treatment options. Activated fibroblasts are the key effector cells in SSc responsible for the excessive production of collagen and the development of fibrosis. Platelet-derived growth factor (PDGF), a potent mitogen for cells of mesenchymal origin, has been implicated in the activation of SSc fibroblasts. Our aim was to examine the therapeutic potential of crenolanib, an inhibitor of PDGF receptor signaling, in cultured fibroblasts and in angiotensin II-induced skin and heart fibrosis. Crenolanib effectively inhibited proliferation and migration of SSc and healthy control fibroblasts and attenuated basal and transforming growth factor-β-induced expression of CCN2/CTGF and periostin. In contrast to healthy control fibroblasts, SSc fibroblasts proliferated in response to PDGFAA, whereas a combination of PDGFAA and CCN2 was required to elicit a similar response in healthy control fibroblasts. PDGF receptor α mRNA correlated with CCN2 and other fibrotic markers in the skin of SSc patients. In mice challenged with angiotensin II, PDGF receptor α-positive cells were increased in the skin and heart. These PDGF receptor α-positive cells co-localized with PDGF receptor β, procollagen, and periostin. Treatment with crenolanib attenuated the skin and heart fibrosis. Our data indicate that inhibition of PDGF signaling presents an attractive therapeutic approach for SSc.

Introduction L’objectif de ce travail est d’etudier les alterations du proteome serique des patients atteints d’hypertension arterielle pulmonaire (HTAP) associee a la clerodermie systemique (SSc), d’identifier les proteines correlees a la severite hemodynamique et determiner leur role potentiel dans la physiopathologie de la maladie. Patients et methodes Les patients eligibles ont ete recrutes dans les centres de reference SSc et/ou HTAP de Boston, Lille, Le Kremlin-Bicetre et Grenoble. Les patients etaient inclus s’ils remplissaient les criteres suivants : diagnostic de SSc selon les criteres ACR/EULAR 2013, forme cutanee limitee, pas de pneumopathie interstitielle diffuse (PID) etendue selon les criteres de Goh, et pas de traitement specifique de l’HTAP. Les patients etaient consideres comme des cas s’ils avaient un diagnostic d’HTAP confirme par catheterisme cardiaque droit (KTD) et un echantillon de serum preleve le meme jour que le KTD. Ils etaient consideres comme des temoins s’ils n’avaient aucun signe evocateur d’HTAP a l’echocardiographie. Resultats Dans une premiere etape exploratoire, l’expression serique de 1129 proteines a ete evaluee chez 15 cas et 16 temoins par analyse proteomique a haut debit (SOMAscan). Nous avons identifie 53 proteines exprimees differentiellement entre les 2 groupes. Parmi ces 53 candidats, seules 2 etaient significativement correlees avec les resistances vasculaires pulmonaires (RVP) : chemerine (p = 0,01, ρ = 0,62) et SET nuclear proto-oncogen (SET) (p = 0,01, ρ = 0,62). Pour valider ces resultats, les taux seriques de chemerine et SET ont ete mesures en ELISA chez 25 cas et 19 controles supplementaires. Les dosages de chemerine etaient de nouveau significativement plus eleves chez les cas (p = 0,01) et correles avec les RVP (p = 0,01, ρ=0,46) dans cette cohorte independante. Dans une deuxieme etape, pour etudier le role physiopathologique potentiel de la chemerine, nous avons realise des marquages en immunofluorescence confocale sur des poumons explantes de temoins sains, de patients SSc-PID sans HTAP et de patients SSc-HTAP. Le marquage du recepteur de chemerine, CMKLR1, etaient significativement augmente sur les cellules musculaires lisses d’artere pulmonaire (CML-AP) de patients SSc-PID et de patients SSc-HTAP. Nous avons ensuite teste l’effet de la chemerine sur la proliferation des CML-AP en stimulant les CML-AP de patients presentant une HTAP idiopathique (HTAPi) avec du serum de patients SSc avec et sans HTAP, en presence ou en l’absence d’un inhibiteur de CMKLR1. On confirmait que les CML-AP d’ HTAPi surexprimaient l’ARNm de CMKLR1 par rapport aux temoins sains (p = 0,03). Le serum des patients SSc-HTAP induisait une proliferation de CML-AP significativement plus elevee (p = 0,005) que le serum des temoins. Cette difference n’etait plus significative (p = 0,69) lors de l’ajout de l’inhibiteur CMKLR1 a-NETA. Conclusion La chemerine semble etre un biomarqueur de substitution valide des RVP dans l’HTAP-SSc. L’elevation de la chemerine circulante et la surexpression de son recepteur, CMKLR1, contribuent a la physiopathologie de l’HTAP-SSc en induisant la proliferation des CML-AP.

In this study we systematically investigated alterations in the serum proteome of patients with diffuse cutaneous systemic sclerosis and identified differentially expressed proteins that correlated with disease severity. Our goal was to identify a combination of serum proteins that would provide a biological measure for the extent of skin disease and that could be combined into a longitudinal pharmacodynamic biomarker. We found that 16% of the sera proteins analyzed by SOMAscan aptamer technology, from two cohorts of patients with diffuse cutaneous systemic sclerosis, were identified as differentially regulated between diffuse cutaneous systemic sclerosis and controls and correlated with modified Rodnan skin score. This dataset showed tumor necrosis factor-α, IFN-γ, transforming growth factor-β, and IL-13 as potential upstream regulators of the serum protein patterns in the sera of patients with diffuse cutaneous systemic sclerosis. By ELISA, two analytes (ST2 and Spondin-1) best described longitudinal change in modified Rodnan skin score, using linear mixed models. This model was then validated in three independent cohorts. In this study we discovered a large array of proteins not previously associated with systemic sclerosis that provide insight into pathogenesis and potential targets for therapeutic intervention. Furthermore, we show that two of these proteins can be combined to form a robust longitudinal biomarker that might be used in clinical trials to assess changes in diffuse cutaneous systemic sclerosis skin disease over time.

Objectives:To investigate alterations in the serum proteome of patients with systemic sclerosis (SSc)-associated pulmonary hypertension (PAH), to identify proteins that correlated with hemodynamic severity and to determine their possible pathogenic role.Methods:Patients were included if they fulfilled the following criteria: diagnosis of limited cutaneous SSc, no extensive interstitial lung disease (ILD), and no treatment with PAH-specific therapy. Patients were classified as cases if they had a definitive diagnosis of PAH confirmed by right heart catheterization (RHC) and a serum sample collected on the same day as RHC. They were classified as controls if they had no sign suggestive of PAH on echocardiography.Results:In a first exploratory step, serum expression of 1129 proteins was assessed in 15 cases and 16 controls by a high-throughput proteomic assay (SOMAscan). We identified 53 proteins differentially expressed between the 2 groups. Among these 53 candidates, only 2 correlated significantly with pulmonary vascular resistance (PVR): chemerin (p=0.01,ρ=0.62) and SET nuclear proto-oncogen (SET) (p=0.01,ρ=0.62).To validate these results, serum levels of chemerin and SET were measured by ELISA assay in 25 additional cases and 19 additional controls. Chemerin levels were confirmed to be significantly higher in cases (p=0.01) and correlated with PVR (p=0.01,ρ=0.46).In a second step, to study the potential pathophysiological role of chemerin, we performed confocal immunofluorescence analyses on explanted lungs of healthy controls, SSc-ILD without PAH and SSc-PAH patients. Chemerin receptor, CMKLR1, was significantly increased on SSc-ILD and SSc-PAH pulmonary artery smooth muscle cells (PA-SMC).We then tested the effect of chemerin on PA-SMC proliferation by stimulating PA-SMCs from idiopathic pulmonary arterial hypertension (iPAH) patients with serum from SSc patients with and without PH, in the presence or absence of a CMKLR1 inhibitor. PA-SMCs from iPAH were confirmed to have higher mRNA expression of CMKLR1 than controls (p=0.03). Serum from SSc-PH patients induced a significantly higher PA-SMC proliferation (p=0.005) than serum from controls. This difference was no longer significant (p=0.69) when adding the CMKLR1 inhibitor α–NETA.Conclusion:Chemerin is a surrogate biomarker for PVR in SSc-PAH. Increased chemerin and its receptor, CMKLR1, contribute to the SSc-PAH pathogenesis by inducing PA-SMC proliferation.Acknowledgments:NoneDisclosure of Interests:Sebastien SANGES: None declared, Lisa Rice: None declared, Ly Tu: None declared, Jean-Luc Cracowski Grant/research support from: JL Cracowski received grants from United Therapeutic, Bioprojet and Topadur, David Montani Grant/research support from: Dr. MONTANI reports grants and personal fees from Actelion, grants and personal fees from Bayer, personal fees from GSK, personal fees from Pfizer, personal fees from MSD, personal fees from Chiesi, outside the submitted work, Julio Mantero: None declared, Camille Ternynck: None declared, Guillemette Marot: None declared, Eric Hachlla: None declared, David Launay Grant/research support from: Dr. Launay reports personal fees from Actelion, grants and personal fees from Takeda, grants and personal fees from CSL Behring, outside the submitted work., Marc Humbert Grant/research support from: Dr. Humbert reports personal fees from Actelion, grants and personal fees from Bayer, grants and personal fees from GSK, personal fees from Merck, from United Therapeutics, personal fees from Acceleron, outside the submitted work., Christophe Guignabert: None declared, Robert Lafyatis Grant/research support from: RL holds research grants from Formation, Elpidera and Kiniksa., Consultant of: R.L. has served as a consultant for Bristol Myers Squibb, Boehringer-Mannheim, Merck, Magenta and Genentech/Roche

Perivascular accumulation of lymphocytes can be a prominent histopathologic feature of various human inflammatory skin diseases. Select examples include systemic sclerosis, spongiotic dermatitis, and cutaneous lupus. Although a large body of work has described various aspects of the endothelial and vascular smooth muscle layers in these diseases, the outer adventitial compartment is poorly explored. The goal of the current study was to characterize perivascular adventitial fibroblast states in inflammatory human skin diseases and relate these states to perivascular lymphocyte accumulation. In normal skin, adventitial fibroblasts are distinguished by CD90 expression, and dense perivascular lymphocytic infiltrates are uncommon. In systemic sclerosis, this compartment expands, but lymphocyte infiltrates remain sparse. In contrast, perivascular adventitial fibroblast expression of VCAM1 is upregulated in spongiotic dermatitis and lupus and is associated with a dense perivascular T cell infiltrate. VCAM1 expression marks transitioned fibroblasts that show some resemblance to the reticular stromal cells in secondary lymphoid organs. Expanded adventitial compartments with perivascular infiltrates similar to the human settings were not seen in the inflamed murine dermis. This species difference may hinder the dissection of aspects of perivascular adventitial pathology. The altered perivascular adventitial compartment and its associated reticular network form a niche for lymphocytes and appear to be fundamental in the development of an inflammatory pattern.

This clinical trial was designed to study the safety and efficacy of blocking IL-1 in skin fibrosis of patients with diffuse cutaneous systemic sclerosis (dcSSc), and to test the hypothesis that inhibition of IL-1 by rilonacept will downregulate expression of the 2G SSc gene biomarker as a surrogate for the modified Rodnan skin score (MRSS).19 dcSSc patients were randomised 2:1 active treatment:placebo in this double blinded trial. Study patients received weekly treatments with either subcutaneous rilanocept 320 mg loading dose at day 0 and then 160 mg for each of the 5 subsequent weekly doses, or placebo. Skin biopsies were taken to test 2G SSc biomarker gene expression at day 0 before treatment and one week after the final study drug dose, comparing gene expression changes between rilonacept- and placebo-treated patients, as well as the change in gene expression at week 6 compared to baseline in rilonacept-treated patients. Safety assessments extended to 6 weeks after the final dose of study drug or placebo. Other secondary outcome measures included global and IL-1-regulated gene expression, serum biomarkers and the MRSS.Rilonacept compared to placebo-treated patients did not show any treatment-related effect on the 2G SSc biomarker. Rilonacept treatment also failed to alter IL-6 expression in skin, serum IL-6, C-reactive protein, or CCL18, a marker of IL-6 activity in SSc.In this small trial we did not observe any effect of blocking IL-1 on clinical skin disease or biomarkers of IL-1 activity.

Vascular alterations are common in human autoimmune skin diseases, including systemic sclerosis and discoid lupus. Much is known about endothelial cell, pericyte and vascular smooth muscle cell activation. In contrast, the adventitial layer of the vascular unit is less well explored. This compartment serves as a reservoir for leukocytes and mesenchymal stem cells, and appears to play important sentinel and remodeling roles. We recently demonstrated that the compartment, as well as the perivascular adventitial fibroblasts, expand in the skin of systemic sclerosis, discoid lupus, and dermatitis patients. Vascular cell adhesion molecule-1 (VCAM) display marked activated adventitial fibroblasts in discoid lupus and dermatitis, and correlated with perivascular T cell infiltration. Here we demonstrate elevated expression of Nerve growth factor receptor (NGFR) by perivascular adventitial fibroblasts in the skin of systemic sclerosis patients but not control subjects. Adventitial NGFR expression occurred without elevated VCAM indicating a distinct activation state. Conversion to the NGFR+ state was also observed in the absence of large, perivascular leukocyte infiltrates. In systemic sclerosis, NGFR was more common than VCAM on perivascular adventitial fibroblasts. Conversely, in discoid lupus lesions, VCAM was more common than NGFR on adventitial fibroblasts suggesting two distinct activation programs. Similar adventitial NGFR staining was seen in both pathological (e.g. hypertrophic and keloid) and normal reparative skin wounds. Our data indicate that elevated NGFR expression can identify an activated perivascular adventitial fibroblast in disease.

Introduction HLA-B*35 is associated with increased risk of developing pulmonary hypertension in SSc patients. We previously reported that HLA-B*35 induces endothelial cell dysfunction via activation of ER stress/UPR and upregulation of the inflammatory response. Because PBMCs from lcSSc-PAH patients are also characterized by activation of ER stress/UPR and inflammation, the goal of this study was to assess whether the presence of HLA-B*35 contributes to those characteristics. Methods PBMCs were purified from healthy controls (n = 49 HC) and lcSSc patients, (n = 44 with PAH, n = 53 without PAH). PBMCs from each group were stratified for the presence of HLA-B*35. Global changes in gene expression in response to HLA-B*35, HLA-B*8 or empty lentivirus were investigated by microarray analysis in HC PBMCs. Total RNA was extracted and qPCR was performed to measure gene expression. Results ER stress markers, in particular the chaperones BiP and DNAJB1 were significantly elevated in PBMC samples carrying the HLA-B*35 allele. IL-6 expression was also significantly increased in HLA-B*35 lcSSc PBMCs and positively correlated with ER stress markers. Likewise, HMGB1 was increased in HLA-B*35-positive lcSSc PBMCs. Global gene expression analysis was used to further probe the role of HLA-B*35. Among genes downregulated by HLA-B*35 lentivirus were genes related to complement (C1QB, C1QC), cell cycle (CDNK1A) and apoptosis (Bax, Gadd45). Interestingly, complement genes (C1QC and C1QB) showed elevated expression in lcSSc without PAH, but were expressed at the low levels in lcSSc-PAH. The presence of HLA-B*35 correlated with the decreased expression of the complement genes. Furthermore, HLA-B*35 correlated with decreased expression of cyclin inhibitors (p21, p57) and pro-apoptotic genes (Bax, Gadd45) in lcSSc B35 subjects. FYN, a tyrosine kinase involved in proliferation of immune cells, was among the genes that were positively regulated by HLA-B*35. HLA-B*35 correlated with increased levels of FYN in lcSSc PBMCs. Conclusions Our study demonstrates that HLA-B*35 contributes to the dysregulated expression of selected ER stress, inflammation and proliferation related genes in lcSSc patient PBMCs, as well as healthy individuals, thus supporting a pathogenic role of HLA-B*35 in the development of PAH in SSc patients. Electronic supplementary material The online version of this article (doi:10.1186/s13075-015-0881-1) contains supplementary material, which is available to authorized users.