Skin Of Systemic Sclerosis Patients Research Articles

The Novel Cytokine Interleukin-41/Meteorin-like Is Reduced in Diffuse Systemic Sclerosis.

Systemic sclerosis (SSc) is an autoimmune connective tissue disease with a triad of features that include vascular abnormalities, inflammation and skin and lung fibrosis. At the core of the disease is the activation of myofibroblasts from quiescent fibroblasts and this can be modified by various cytokines. IL-41 is a recently described cytokine that was initially characterised as an adipokine as it was highly expressed in adipocytes and adipose tissue. However, it has recently been identified as being widely expressed and has immunomodulatory functions. This study examined the circulating levels of IL-41 and its expression in skin biopsies. We demonstrated significantly reduced levels of IL-41 in diffuse SSc that was also mirrored in the skin of SSc patients. AMPK has been proposed as a downstream target of IL-41, so we also measure mammalian target of rapamycin in skin and found that this is elevated in SSc patients. We speculate that IL-41 maybe an antifibrotic cytokine and its reduction may facilitate the activation of fibroblasts.

Assessment of Skin by High Frequency Musculoskeletal Ultrasound in Egyptian Patients with Systemic Sclerosis

Abstract Background Fibrotic involvement of the skin is a cardinal feature of systemic sclerosis (SSc). The extent of skin involvement is associated with internal organ involvement with severe disease course and poor prognosis. SSc skin involvement is characterized by three phases in temporal sequence: edematous, fibrotic, and atrophic. A palpation-based semi- quantitative score, the modified Rodnan skin score (mRSS) is widely used for the assessment of skin involvement. It is a quick, noninvasive clinical assessment that correlates with histological grading of skin fibrosis. However, it lacks the sensitivity to differentiate between clinically indistinguishable pathological phases such as inflammatory edema vs. established fibrosis. More objective approaches to measure skin involvement imaging have been developed in the past decades.In our study, we review the use of ultrasound for the assessment of early changes in skin thickness and echogenicity in patients with SSc, focusing. mainly on high frequency ultrasound. Aim of the Work to evaluate the role of high frequency ultrasound (HFUS) of skin in assessment of early changes in skin thickness and echogenicity in patients with SSc. Patients and Methods Our study is a cross-sectional, observational study involving homogenous groups consisting of 23 SSc patients and 21 healthy age and sex matched controls. Patients who fulfilled the 2013 ACR/EULAR Classification Criteria for SSc. Results DT was evaluated by both mRSS and HFUS at 5 skin areas in both patients and control. We found statistically significant difference between the two studied groups as regards in area 1 longitudinal (P = 0.017) and area 1 in transverse (P = 0.038), tendency to significance in area 2 (P = 0.054). Subclinical dermal involvement was detected by HFUS even in the skin areas in patients who had a normal local MRSS ( These areas were not planned to be assessed by high frequency ultrasound but added to the five areas to be assessed to evaluate for ultrasound detected subclinical involvement of skin in SSc patients ). In particular, DT was highly significantly greater in patients with area with Rodnan zero score at dorsum of hand than in healthy subjects (longitudinal and transverse) (P < 0.001, 0.005 ) respectively. Similar changes at the level of echogenicity occurred in determination of the stage of the disease, with increased skin thickness and decreased echogenicity occurring early and during skin disease activity due to edema; and decrease skin thickness and increased echogenicity occurring late with skin atrophy Conclusion that high frequency ultrasound is a useful tool in assessment of skin pathologic changes (even subclinical changes) in terms of thickness and echogenicity in patients with SSc both at disease onset and during follow up of response to therapy and disease stage. Moreover, it could be a useful screening tool with definite cutoff values at certain areas that differentiate normal from pathologic skin thickness.

SLC39A7 upregulation links to skin fibrosis in systemic sclerosis via TGF-β/SMAD pathway.

Systemic sclerosis (SSc) is a multisystem connective tissue disease. Skin fibrosis, the hallmark of this disease, is defined as the excess deposition and accumulation of extracellular matrix, mainly type 1 collagen, in the dermis. SLC39A7 is an intracellular zinc transporter that plays a unique role in connective tissue formation. Therefore, we investigated the expression and role of SLC39A7 in SSc. Using immunohistochemical staining we demonstrated the overexpression of SLC39A7 in the skin of SSc patients. Quantitative real-time PCR and western blot data analysis showed that both SLC39A7 mRNA and protein levels were significantly upregulated in dermal fibroblasts from SSc patients compared to healthy controls. We used the shRNA lentiviral particle transduction system to stably knockdown the expression of SLC39A7 in SSc fibroblasts. The results showed that knockdown of SLC39A7 suppressed the production of type 1 collagen. These findings provide evidence that SLC39A7 is involved in the pathogenesis of SSc and that SLC39A7 plays a positive role in its progression.

Blockade of IL-11 Trans-Signaling or JAK2/STAT3 Signaling Ameliorates the Profibrotic Effect of IL-11

ABSTRACT Objectives Systemic sclerosis (SSc) is a rare rheumatic disease characterized by vascular damage, dysregulated immune response, and fibrosis. Interleukin−11 (IL−11) is upregulated in SSc. This study aimed to investigate the pathological and therapeutic role of the IL−11 trans-signaling pathway in SSc. Methods Plasma IL−11 level was evaluated in 32 patients with SSc and 15 healthy controls, while the expression levels of ADAM10, ADAM17, IL−11, IL−11 Rα, or IL−11 co-stained with CD3 or CD163 in the skin of SSc patients and healthy controls were analyzed. Fibroblasts were treated with IL−11 and ionomycin to evaluate the profibrotic effect of IL−11 trans-signaling pathway. TJ301 (sgp130Fc) and WP1066 (a JAK2/STAT3 inhibitor) intervention groups were set up to investigate the antifibrotic effect of targeting IL−11. Results Levels of plasma IL−11 were extremely low in most SSc patients and healthy controls. In contrast, levels of IL−11, IL−11 Rα, and ADAM10, but not ADAM17, were significantly elevated in the skin of SSc patients. Moreover, the numbers of IL−11+ CD3+ cells and IL−11+ CD163+ cells were increased in the skin of SSc patients. Besides, IL−11 and ADAM10 were also elevated in the skin and pulmonary of bleomycin-induced SSc mouse. Fibroblasts co-stimulated with IL−11 and ionomycin showed increased expression of COL3 and phosphorylation of STAT3, which could be inhibited by TJ301 or WP1066. TJ301 also ameliorated skin and lung fibrosis in BLM-induced SSc mouse. Conclusions IL−11 induces fibrosis in SSc by regulating the trans-signaling pathway. Blockage of sgp130Fc or inhibition of the JAK2/STAT3 pathway could ameliorate the profibrotic effect of IL−11.

High frequency ultrasound assessment of skin in systemic sclerosis patients

To evaluate the role of high frequency ultrasound (HFU) in assessing skin changes in terms of thickness and echogenicity in systemic sclerosis (SSc) patients with early and late changes. Twenty-three SSc patients were enrolled along with 21 matched controls. Skin thickness was assessed using modified Rodnan skin score (mRSS) and HFU. Patients had mean age of 41.8 ± 9.1 years, 91.3% were females, mean disease duration 6.0 ± 4.6 years, 11 patients had early (<5 years) and 12 late (≥5 years) disease, 8 patients had limited (lcSSc) and 15 diffuse (dcSSc) cutaneous SSc. Antinuclear antibody was positive in 17 (73.9%) and antiscleroderma-17 in 18 (78.3%). Patients had significantly thicker skin between second and third metacarpophalangeal joint (L = 1.52 ± 0.35 mm vs 1.25 ± 0.35 mm; p = 0.017 and T = 1.48 ± 0.34 mm vs 1.26 ± 0.33 mm; p = 0.038 respectively). Patients with early disease had thicker skin than those with late disease. HFU dermal thickness showed no significant difference according to gender, subtypes, presence and absence of clinical manifestations or autoantibody positivity. There was significant higher dermal thickness in patients with reflux (p = 0.009) and was lower in patients with interstitial pulmonary fibrosis (p < 0.05). There was negative correlation between US dermal thickness and disease duration (p < 0.05). mRSS showed no correlation with HFU dermal thickness in all areas. HFU is useful in assessing skin pathologic changes (even subclinical changes) in terms of thickness and echogenicity in SSc patients. Moreover, it could be a potential screening tool in differentiating normal from pathologic skin thickness.

Cathepsin B/NLRP3/GSDMD axis-mediated macrophage pyroptosis induces inflammation and fibrosis in systemic sclerosis

BackgroundPyroptosis is a newly discovered type of programmed cell death associated with inflammatory and fibrotic diseases. Macrophages play an important role in inducing early immune inflammation in systemic sclerosis (SSc). ObjectiveTo investigate the effect of macrophages pyroptosis on fibrosis of SSc. MethodsPyroptosis/inflammatory markers in serum and skin of SSc patients were detected. Bleomycin (BLM) was subcutaneously injected to establish SSc mouse model. The levels of pyroptosis markers, dermal thickness and collagen deposition in skin were assessed before and after the administration of pyroptosis inhibitors, including MCC950, Disulfiram and necrosulfonamide (NSA). Human-derived monocyte-macrophage cell line (THP-1) or mouse bone marrow-derived macrophages (BMDMs) were primed with lipopolysaccharide (LPS) and stimulated by silicon dioxide (SiO2) to induce cell pyroptosis. Fibroblasts from patients with SSc were co-cultured with pyroptotic THP-1 cells, and the collagen production was assessed. ResultsPyroptotic/inflammatory proteins, including NLRP3, cleaved-Caspase (CASP)1, GSDMD-N terminal and IL-18 were increased in the serum, and ASC aggregation and GSDMD were elevated in macrophages in the skin of SSc patients. SSc mice showed increased pyroptosis markers, dermal thickness and collagen deposition in skins, which were alleviated by MCC950, Disulfiram and NSA. Pyroptosis of THP-1 cells and BMDMs was induced by LPS/SiO2, and it was reduced by the inhibitors of Cathepsin B, NLRP3, CASP1 and GSDMD. Co-culture with pyroptotic THP-1 cells increased the fibrotic proteins in fibroblasts, which were alleviated by pyroptosis inhibitors. ConclusionsSSc patients and BLM-induced mouse model presented increased pyroptosis. LPS/SiO2-induced macrophage pyroptosis promoted fibrosis of SSc through Cathepsin B/NLRP3/GSDMD pathway.

595 Type I interferon contributes to vasculopathy and accelerated fibrosis in systemic sclerosis

Systemic sclerosis (SSc) is one of the most devastating autoimmune diseases characterized by vasculopathy and fibrosis that affects both skin and internal organs. IFN signature is present in blood and skin in SSc patients. Polymorphisms of IFN regulatory genes IRF-4,5,7,8 and STAT4 have been found to be associated with SSc. Despite these evidence, the exact role of IFN in SSc remains poorly understood. We performed single-cell RNA sequencing on the skin from patients with diffuse SSc(dSSc), limited SSc(lSSc) and normal controls.

Profibrotic Effects of Endothelin-1 on Fibroblasts Are Mediated by Aldosterone in Vitro: Relevance to the Pathogenesis and Therapy of Systemic Sclerosis and Pulmonary Arterial Hypertension.

Endothelin-1 (ET-1) is a vasoactive and profibrotic peptide that plays a pivotal role in diseases such as systemic sclerosis (SSc) and pulmonary arterial hypertension (PAH), by inducing fibrosis and vascular remodeling. Such effects may be sustained by the induction of aldosterone production and reactive oxygen species (ROS). We have used fibroblasts obtained from skin of healthy donors and SSc patients and commercial fibroblasts from lung to evaluate whether ET-1 is able to stimulate ROS production directly or indirectly through aldosterone induction. We found that ET-1 receptors are present in all types of fibroblasts analyzed, whereas the expression of mineralocorticoid receptor (MCR) is lower in dermal fibroblasts from healthy donors (HDFs) compared to fibroblasts derived from lung (HPFs) or from skin of SSc patients (SScHDFs). ET-1 induces ROS production in HDFs and SScHDFs after 24 h of incubation involving its receptor B (ETB), whereas aldosterone exerts its effects after 40 min of incubation. Moreover, ROS production was inhibited by the pre-incubation of cells with MCR inhibitor. Our results indicate that ET-1 induces ROS indirectly through aldosterone production suggesting that aldosterone may play a pivotal role in the pathogenesis of SSc and PAH.

Dersimelagon, a novel oral melanocortin 1 receptor agonist, demonstrates disease-modifying effects in preclinical models of systemic sclerosis

BackgroundActivation of melanocortin 1 receptor (MC1R) is known to exert broad anti-inflammatory and anti-fibrotic effects. The purpose of this study is to investigate the potential of dersimelagon, a novel oral MC1R agonist, as a therapeutic agent for systemic sclerosis (SSc).MethodsThe effects of dersimelagon phosphoric acid (MT-7117) on skin fibrosis and lung inflammation were evaluated in bleomycin (BLM)-induced SSc murine models that were optimized for prophylactic and therapeutic evaluation. Microarray-based gene expression analysis and serum protein profiling were performed in the BLM-induced SSc models. The effect of MT-7117 on transforming growth factor-β (TGF-β)-induced activation of human dermal fibroblasts was evaluated in vitro. Immunohistochemical analyses of MC1R expression in the skin of SSc patients were performed.ResultsProphylactic treatment with MT-7117 (≥ 0.3 mg/kg/day p.o.) significantly inhibited skin fibrosis and lung inflammation, and therapeutic treatment with MT-7117 (≥ 3 mg/kg/day p.o.) significantly suppressed the development of skin fibrosis in the BLM-induced SSc models. Gene array analysis demonstrated that MT-7117 exerts an anti-inflammatory effect via suppression of the activation of inflammatory cells and inflammation-related signals; additionally, vascular dysfunction was extracted as the pathology targeted by MT-7117. Serum protein profiling revealed that multiple SSc-related biomarkers including P-selectin, osteoprotegerin, cystatin C, growth and differentiation factor-15, and S100A9 were suppressed by MT-7117. MT-7117 inhibited the activation of human dermal fibroblasts by suppressing TGF-β-induced ACTA2 (encoding α-smooth muscle actin) mRNA elevation. MC1R was expressed by monocytes/macrophages, neutrophils, blood vessels (endothelial cells), fibroblasts, and epidermis (keratinocytes) in the skin of SSc patients, suggesting that these MC1R-positive cells could be targets for MT-7117.ConclusionsMT-7117 demonstrates disease-modifying effects in preclinical models of SSc. Investigations of its mechanism of action and target expression analyses indicate that MT-7117 exerts its positive effect by affecting inflammation, vascular dysfunction, and fibrosis, which are all key pathologies of SSc. The results of the present study suggest that MT-7117 is a potential therapeutic agent for SSc. A phase 2 clinical trial investigating the efficacy and tolerability of MT-7117 in patients with early, progressive diffuse cutaneous SSc is currently in progress.

Expression and Pathogenic Analysis of Integrin Family Genes in Systemic Sclerosis

Objectives: Emerging evidence shows that integrin members are involved in inflammation and fibrosis in systemic sclerosis (SSc). This study aimed at evaluating the expression of integrin family genes in the skin tissue from SSc patients and exploring the potential pathogenic mechanism.Methods: We utilized the public datasets of SSc skin tissue from the Gene Expression Omnibus (GEO) database to analyze the expression and clinical significance of integrin family genes in SSc. The expression of integrin members in skin tissue was also assessed by immunohistochemistry. In addition, functional enrichment and pathway analysis were conducted.Results: Compared with healthy controls, the mRNA and protein levels of ITGA5, ITGB2, and ITGB5 were upregulated in the skin of SSc patients. Further analysis indicated that the mRNA expression levels of ITGA5, ITGB2, and ITGB5 were positively correlated with modified Rodnan skin thickness score (mRSS). Functional enrichment and pathway analysis showed that integrin members may play multiple roles in the pathogenesis of SSc. Among them, ITGA5, ITGB2, and ITGB5 might synergistically promote SSc through affecting extracellular matrix (ECM) turnover, ECM–receptor interaction, focal adhesion, and leukocyte trans-endothelial migration, while ITGA5 and ITGB5 also might affect angiogenesis and endothelial cell function. In addition, ITGA5, ITGB2, and ITGA5 were associated with different pathways, respectively. ITGA5 was uniquely enriched for actin organization, while ITGB5 was for TGF-β signaling and ITGB2 for immune cell activation.Conclusion: Our results implied that the abnormal expression of integrin family genes including ITGA5, ITGB2, and ITGB5 may participate in multiple pathological processes in SSc. Further investigations are required for confirming this speculation.

Circulating classical monocytes share a common transcriptional signature with skin macrophages in Systemic Sclerosis

Abstract The etiology and pathogenesis of systemic sclerosis (SSc) are poorly understood. Circulating monocytes likely play a critical role in SSc progression through secretion of proinflammatory molecules and as precursors of macrophages that can reorganize the extracellular matrix, thereby leading to development of end-organ fibrosis. Here, we evaluate the transcriptional similarities between circulating classical monocytes (CMo) and skin macrophages of SSc patients. Bulk RNA-seq was performed on sorted CMo from SSc blood obtained through the Prospective Registry of Early Systemic Sclerosis (PRESS) cohort, and transcriptional profiles were analyzed along with profiles from matched control samples. Additionally, sorted CD45+ cells from skin biopsies of one SSc patient and one control patient were prepared for single-cell RNA-seq. There was a numerical expansion of skin macrophages from the control to the SSc sample, but no significant difference in the quantity of circulating CMo between control and SSc patients. Of the 152 significantly upregulated genes (DESeq2, p&amp;lt;0.05, fold change&amp;gt;2) observed in circulating CMo population and the 290 upregulated genes (fold change&amp;gt;2) in the skin macrophage cluster compared to their respective controls, we found 23 genes in common (p&amp;lt;1.23×10−8, hypergeometric distribution test). These shared genes were involved in various immune and inflammatory regulation processes. These data indicate that a common transcriptional signature may exist between circulating CMo and macrophages present in the skin of SSc patients, potentially suggesting that macrophage-specific pathways at the site of fibrosis can be detected in a circulating precursor population.

How much of skin improvement over time in systemic sclerosis is due to normal ageing? A prospective study with shear-wave elastography

BackgroundMeasurement of skin involvement is essential for the diagnosis and assessment of prognosis and disease progression in systemic sclerosis (SSc). The modified Rodnan skin score (mRSS) is the gold standard measure of skin thickness, but it has been criticised for the lack of objectivity, poor inter-observer reproducibility and lack of sensitivity to change. Recently, shear-wave elastography (SWE) emerged as a promising tool for the objective and quantitative assessment of the skin in SSc patients. However, no studies have evaluated its sensitivity to change over time.ObjectiveTo assess changes in skin stiffness in SSc patients using SWE during a 5-year follow-up.MethodsSkin stiffness [i.e. shear-wave velocity values (SWV) in metres per second] was assessed by SWE ultrasound (using virtual touch image quantification) at the 17 sites of the mRSS, in each participant, at baseline and follow-up. mRSS was performed at both time points. Differences between groups were analysed using the related-samples Wilcoxon signed-rank test and the Mann–Whitney U test.ResultsWe included 21 patients [85.7% females; mean age 56.3 (10.4) years at baseline, 57.1% with limited SSc] and 15 healthy controls [73.3% females; mean age 53.6 (14.1) years)]. The median follow-up was 4.9 (0.4) years.Skin stiffness decreased significantly at all Rodnan sites (p ≤ 0.001) (except in the fingers), in SSc patients, over time. The same phenomenon occurred in controls, but to a lesser degree, in terms of percentage change.The percentage reduction in skin stiffness varied in the different Rodnan sites and in different phases of the disease. In addition, SWV values also decreased significantly in 15/16 skin sites with local normal Rodnan at baseline, whereas local Rodnan skin score only changed significantly in the upper arm (p = 0.046) and forearm (p = 0.026).ConclusionThis study provides first-time evidence suggesting that skin SWV values are more sensitive to change over time than mRSS and reduce significantly over time in SSc and normal controls.

CCL3, IL-7, IL-13 and IFNγ transcripts are increased in skin's biopsy of systemic sclerosis.

Although several cytokines and chemokines have been investigated as possible mediators of fibrosis in systemic sclerosis (SSc), specific correlation between cytokines and organ involvement have not been found yet, and a cytokine profile characteristic of SSc is far to be identified. We studied the profile of antifibrotic and profibrotic transcripts involved in skin of SSc patients. The mRNA expression was detected by fluorescence-based quantitative real-time PCR (qPCR) in skin's biopsies from 14 patients with SSc and 5 healthy controls. PDGF-A, CTGF, CCL3, IL-6, IL-13, IL-7, IFNγ, IL-17, IL-22 and RORc were analysed in these samples. CCL3, IL-7, IL-13 and IFN-γ were more expressed in skin's biopsy of patients with SSc (P=0.0002, P=0.0082, P=0.0243, P=0.0335, respectively) when compared with healthy controls. We also found a positive correlation between CCL3 and IL-7 transcripts (P=0.0050 r=0.7187). Furthermore, we observed that patients with lung involvement had lower expression of PDGF-A (P=0.0385). We found an increase in IL-7, IFN-γ, CCL3 and IL-13 relative mRNA expressions on the skin's biopsy of patients with SSc, and a positive correlation between IL-7 and CCL3. These molecules are involved in the pathogenesis of SSc, and how their interactions occur should be the subject of further studies.

Fos-related antigen-1 transgenic mouse as a model for systemic sclerosis: A potential role of M2 polarization.

To investigate the systemic sclerosis-related phenotype in fos-related antigen-1 transgenic mice and its underlying mechanisms. Lung and skin sections of constitutive fos-related antigen-1 transgenic mice and wild-type mice were examined by tissue staining and immunohistochemistry. The tricuspid regurgitation pressure gradient was measured by transthoracic echocardiography with a Doppler technique. To assess the impact of fos-related antigen-1 expression on macrophage function, bone marrow-derived mononuclear cells were derived from mice that expressed fos-related antigen-1 under the control of doxycycline and wild-type littermates. These bone marrow-derived mononuclear cells were induced to differentiate into macrophages with or without doxycycline, and analyzed for gene and protein expression. Finally, lung explants obtained from systemic sclerosis patients and control donors were subjected to immunohistochemistry. The lungs of fos-related antigen-1 transgenic mice showed excessive fibrosis of the interstitium and thickening of vessel walls, with narrowing lumen, in an age-dependent manner. The tricuspid regurgitation pressure gradient was significantly elevated in fos-related antigen-1 transgenic versus control mice. Increased dermal thickness and the loss of subdermal adipose tissue were also observed in the fos-related antigen-1 transgenic mice. These changes were preceded by a perivascular infiltration of mononuclear cells, predominantly consisting of alternatively activated or M2 macrophages. Overexpressing fos-related antigen-1 in bone marrow-derived mononuclear cell cultures increased the expression of M2-related genes, such as Il10, Alox15, and Arg1. Finally, fos-related antigen-1-expressing M2 macrophages were increased in the lung tissues of systemic sclerosis patients. The fos-related antigen-1 transgenic mouse serves as a genetic model of systemic sclerosis that recapitulates the major vascular and fibrotic manifestations of the lungs and skin in systemic sclerosis patients. M2 polarization mediated by the up-regulation of fos-related antigen-1 may play a critical role in the development of systemic sclerosis.

Nerve growth factor receptor expression marks activated human perivascular adventitial fibroblasts in distinct perturbed states

Abstract 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.

Blockade of PDGF Receptors by Crenolanib Has Therapeutic Effect in Patient Fibroblasts and in Preclinical Models of Systemic Sclerosis

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.

Na+ deposition in the fibrotic skin of systemic sclerosis patients detected by 23Na-magnetic resonance imaging.

Na+ deposition in the fibrotic skin of systemic sclerosis patients detected by 23Na-magnetic resonance imaging.

Integration of microRNA and mRNA expression profiles in the skin of systemic sclerosis patients

MicroRNAs (miRNAs) play important roles in the fibrosis of systemic sclerosis (SSc). However, the underlying miRNA-mRNA regulatory network is not fully understood. A systemic investigation of the role of miRNAs would be very valuable for increasing our knowledge of the pathogenesis of SSc. Here, we combined miRNA and mRNA expression profiles and bioinformatics analyses and then performed validation experiments. we identified 21 miRNAs and 2698 mRNAs that were differentially expressed in SSc. Among these, 17 miRNAs and their 33 target mRNAs (55 miRNA-mRNA pairs) were involved in Toll-like receptor, transforming growth factor β and Wnt signalling pathways. Validation experiments revealed that miR-146b, miR-130b, miR-21, miR-31 and miR-34a levels were higher whereas miR-145 levels were lower in SSc skin tissues and fibroblasts, normal fibroblasts and endothelial cells that were stimulated with SSc serum. ACVR2B, FZD2, FZD5 and SOX2 levels were increased in SSc skin fibroblasts, normal fibroblasts and endothelial cells that were stimulated with SSc serum. We did not identify any negative correlations among these miRNA-mRNA pairs. miR-21 was specifically expressed at higher levels in SSc serum. Six miRNAs and 4 mRNAs appear to play important roles in the pathogenesis of SSc are worth investigating in future functional studies.

Angiostatic and Angiogenic Chemokines in Systemic Sclerosis: An Overview

In systemic sclerosis (SSc), the dysregulation of several molecular pathways seem to have a role in the disease pathogenesis. Either angiogenesis and vasculogenesis are disturbed and impaired, and an imbalance between angiogenic and angiostatic factors may be involved in the genesis and maintenance of vasculopathy. Aberrant immune system activation and function involves both B and T cells, as well as many different chemokines and cytokines. Particularly, chemokines are central to the initiation and maintenance of inflammatory responses as well as angiogenesis and fibrosis. Increased expression of several chemokines as CXCL4 (platelet factor 4), CXCL8 (IL8), CXCL5 (ENA-78), CCL5 (RANTS), CXCL9 (MIG), CCL24, CXCL10 IP-10), CXCL12, CXCL16 (SRPSDX), CCL2 (MCP-1), CCL19 (MIP-3β/ELC), CCL24 (Eotaxin 2), suggests a complex mechanism by which many immune cell types, including T cells, macrophages and neutrophils are recruited to the skin in SSc patients. Many of these chemokines have redundant roles, possibly to ensure recruitment of specific cell types. Several studies have shown a synergistic effect of combinations of these chemokines in cell recruitment, emphasizing the importance of understanding global chemokine expressions. urthermore, chemokines can be detected in peripheral blood compared with cytokines or growth factors. The utility of cytokines as biomarkers has been investigated but longitudinal studies are necessary to clarify their clinical utility for the evaluation of disease activity, therapeutic effects on skin sclerosis or interstitial lung disease and risk stratification of SSc patients. An effective therapeutic agent, able to interfere with complex chemokine networks, is warranted to attenuate perivascular inflammation, dysregulated angiogenesis and the evolution of skin and internal organ fibrosis, is the most ambitious goal for the scientific research of the future.

Altered Dermal Fibroblasts in Systemic Sclerosis Display Podoplanin and CD90

Tissue injury triggers the activation and differentiation of multiple cell types to minimize damage and initiate repair processes. In systemic sclerosis, these repair processes appear to run unchecked, leading to aberrant remodeling and fibrosis of the skin and multiple internal organs, yet the fundamental pathological defect remains unknown. We describe herein a transition wherein the abundant CD34(+) dermal fibroblasts present in healthy human skin disappear in the skin of systemic sclerosis patients, and CD34(-), podoplanin(+), and CD90(+) fibroblasts appear. This transition is limited to the upper dermis in several inflammatory skin diseases, yet in systemic sclerosis, it can occur in all regions of the dermis. Invitro, primary dermal fibroblasts readily express podoplanin in response to the inflammatory stimuli tumor necrosis factor and IL-1β. Furthermore, we show that on acute skin injury in both human and murine settings, this transition occurs quickly, consistent with a response to inflammatory signaling. Transitioned fibroblasts partially resemble the cells that form the reticular networks in organized lymphoid tissues, potentially linking two areas of fibroblast research. These results allow for the visualization and quantification of a basic stage of fibroblast differentiation in inflammatory and fibrotic diseases in the skin.