The role of genetics and epigenetics in the pathogenesis of systemic sclerosis. Nat Rev Rheumatol. 2014;10:671-681. [PMID: 25136786 DOI: 10.1038/nrrheum.2014.128]

miR-143-3p boosts extracellular vesicles to improve the dermal fibrosis of localized scleroderma

Localized scleroderma (LoSc) is an autoimmune disease that features extensive fibrosis of the skin. Due to its severity and limited understanding, no effective treatments have been developed to date. Bone marrow mesenchymal stem cells (BMSCs) derived extracellular vesicles (EVs) have been demonstrated promising therapeutic effects on the LoSc mouse model in our previous study. However, identifying the targets and underlying mechanisms of EVs remains a significant challenge for therapeutic applications. miR-143-3p, a critical and abundant factor in BMSC-EVs identified through miRNA sequencing, mediates antifibrotic effects in a LoSc mouse model and is significantly lacking in the dermis of LoSc patients. This microRNA inhibits myofibroblast formation and collagen synthesis, contributing to the therapeutic effects of BMSC-EVs in the LoSc mouse model. Moreover, miR-143-3p-reinforced BMSC-EVs demonstrated enhanced therapeutic efficacy compared to normal BMSC-EVs, reducing dermal thickening, collagen deposition, fibroblast differentiation into myofibroblasts, and promoting skin tissue remodeling. IGF1R, highly expressed in the skin of LoSc, was identified as a potential target of miR-143-3p and was inhibited by miR-143-3p-reinforced EVs, thereby modulating the IGF1/IGF1R-AKT/MAPK pathway. In conclusion, miR-143-3p-enriched EVs could be a more efficient candidate for treating dermal fibrosis in LoSc.

IL-21 drives skin and lung inflammation and fibrosis in a model for systemic sclerosis

BACKGROUND

Systemic sclerosis (SSc) is an autoimmune disease characterized by vasculopathy, abnormal inflammation, and fibrosis of the skin and internal organs, notably the skin and lungs, significantly impairing quality of life. There is currently no cure for SSc, and its etiology remains largely unknown, presenting a primary barrier to effective treatment. We investigated the role of interleukin-21 (IL-21) in the pathogenesis of SSc.

METHODS

We assessed the expression levels of fibrosis-related genes in human dermal fibroblasts exposed to IL-21 and TGF beta. We also induced SSc in wild-type C57BL/6 mice and IL-21 knockout (KO) mice with a C57BL/6 background using bleomycin (Bleomycin). Histological analyses were conducted on skin and lung tissues from these mice. The distribution and expression levels of fibrosis-related proteins in the tissues were examined via immunohistochemistry and quantitative real-time PCR. Furthermore, we measured the frequency of Th1, Th2, and Th17 cells among splenocytes through flow cytometry.

RESULTS

IL-21 activation led to STAT3 phosphorylation more than TGF beta in dermal fibroblasts. In IL-21 KO mice with BLM-induced SSc, skin thickness and lung fibrosis were reduced. The absence of IL-21 in these mice resulted in suppressed expression of fibrosis-related genes, including Col1a1, Col1a2, Col3a1, CTGF, α-SMA, STAT3, and TGFβ, in the skin and lungs. It also led to a decreased frequency of Th1, Th2, and Th17 cells, as well as a lower Th17/Treg ratio among splenocytes, factors known to contribute to the development of SSc.

CONCLUSIONS

IL-21 contributes to the development of SSc by promoting the expression of fibrosis-related genes and modulating the levels of CD4+ T cells.

Effects of probiotics supplementation in gastrointestinal complications and quality of life of patients with systemic sclerosis: A systematic review

Background

Systemic sclerosis (SSc), as an autoimmune rheumatic disease characterized by immune dysregulation and vasculopathy, affects multiple organs. Due to the high burden of its symptoms on the health care system, this study aims to investigate the effects of probiotic supplements in patients with SSc.

Methods

We searched electronic databases with predefined search terms in PubMed, Scopus, and ISI Web of Science up to June 2023. Randomized controlled trials that evaluated the effects of probiotic supplementation in adult patients suffering from SSc were included in the study. Results of the included studies were reported as weighted mean difference (WMD) with a 95 % confidence interval (CI).

Results

Four studies met the inclusion criteria and were included in the meta-analysis. There was a total of 176 SSc patients. The results show a significant effect of probiotics supplementation on gastrointestinal (GI) symptoms containing reflux (WMD: -0.36, 95 % CI: -0.51 to -0.22, p-value <0.001), gas and bloating (WMD: -0.88, 95 % CI: -1.05 to -0.7, p-value<0.001). However, the results for constipation (WMD: -0.12, 95 % CI: -0.27 to 0.04, p-value = 0.13), diarrhea (WMD: -0.14, 95 % CI: -0.31 to 0.03, p-value = 0.10), and fecal incontinence (WMD: 0.04, 95 % CI: -0.06 to 0.15, p-value = 0.43) were insignificant.

Conclusion

Supplementing with probiotics may alleviate a few numbers of GI complications in SSc. Nevertheless, due to the limited number of studies, more well-designed studies are needed to strengthen these results.

RNA methylation: A potential therapeutic target in autoimmune disease

Autoimmune diseases such as rheumatoid arthritis (RA), systemic lupus erythematosus (SLE), and inflammatory bowel disease (IBD) are caused by the body's immune response to autoantigens. The pathogenesis of autoimmune diseases is unclear. Numerous studies have demonstrated that RNA methylation plays a key role in disease progression, which is essential for post-transcriptional regulation and has gradually become a broad regulatory mechanism that controls gene expression in various physiological processes, including RNA nuclear output, translation, splicing, and noncoding RNA processing. Here, we outline the writers, erasers, and readers of RNA methylation, including N6-methyladenosine (m6A), 2'-O-methylation (Nm), 2'-O-dimethyladenosine (m6Am), N1-methyladenosine (m1A), 5-methylcytidine (m5C) and N7-methylguanosine (m7G). As the role of RNA methylation modifications in the immune system and diseases is explained, the potential treatment value of these modifications has also been demonstrated. This review reports the relationship between RNA methylation and autoimmune diseases, highlighting the need for future research into the therapeutic potential of RNA modifications.

MicroRNA-21a-5p inhibition alleviates systemic sclerosis by targeting STAT3 signaling

BACKGROUND

MicroRNA (miRNA)-21-5p participates in various biological processes, including cancer and autoimmune diseases. However, its role in the development of fibrosis in the in vivo model of systemic sclerosis (SSc) has not been reported. This study investigated the effects of miRNA-21a-5p overexpression and inhibition on SSc fibrosis using a bleomycin-induced SSc mouse model.

METHODS

A murine SSc model was induced by subcutaneously injecting 100 μg bleomycin dissolved in 0.9% NaCl into C57BL/6 mice daily for 5 weeks. On days 14, 21, and 28 from the start of bleomycin injection, 100 μg pre-miRNA-21a-5p or anti-miRNA-21a-5p in 1 mL saline was hydrodynamically injected into the mice. Fibrosis analysis was conducted in lung and skin tissues of SSc mice using hematoxylin and eosin as well as Masson's trichrome staining. Immunohistochemistry was used to examine the expression of inflammatory cytokines, phosphorylated signal transducer and activator of transcription-3 (STAT3) at Y705 or S727, and phosphatase and tensin homologue deleted on chromosome-10 (PTEN) in skin tissues of SSc mice.

RESULTS

MiRNA-21a-5p overexpression promoted lung fibrosis in bleomycin-induced SSc mice, inducing infiltration of cells expressing TNF-α, IL-1β, IL-6, or IL-17, along with STAT3 phosphorylated cells in the lesional skin. Conversely, anti-miRNA-21a-5p injection improved fibrosis in the lung and skin tissues of SSc mice, reducing the infiltration of cells secreting inflammatory cytokines in the skin tissue. In particular, it decreased STAT3-phosphorylated cell infiltration at Y705 and increased the infiltration of PTEN-expressing cells in the skin tissue of SSc mice.

CONCLUSION

MiRNA-21a-5p promotes fibrosis in an in vivo murine SSc model, suggesting that its inhibition may be a therapeutic strategy for improving fibrosis in SSc.

Neurological, cardiac, musculoskeletal, and renal manifestations of scleroderma along with insights into its genetics, pathophysiology, diagnostic, and therapeutic updates

Background

Scleroderma, also referred to as systemic sclerosis, is a multifaceted autoimmune condition characterized by abnormal fibrosis and impaired vascular function. Pathologically, it encompasses the persistent presence of inflammation, abnormal collagen buildup, and restructuring of blood vessels in various organs, resulting in a wide range of clinical symptoms. This review incorporates the most recent scientific literature on scleroderma, with a particular emphasis on its pathophysiology, clinical manifestations, diagnostic approaches, and treatment options.

Methodology

A comprehensive investigation was carried out on numerous databases, such as PubMed, MEDLINE, Scopus, Web of Science, and Google Scholar, to collect pertinent studies covering diverse facets of scleroderma research.

Results

Scleroderma presents with a range of systemic manifestations, such as interstitial lung disease, gastrointestinal dysmotility, Raynaud's phenomenon, pulmonary arterial hypertension, renal complications, neurological symptoms, and cardiac abnormalities. Serological markers, such as antinuclear antibodies, anti-centromere antibodies, and anti-topoisomerase antibodies, are important for classifying diseases and predicting their outcomes.

Discussion

The precise identification of scleroderma is crucial for promptly and correctly implementing effective treatment plans. Treatment approaches aim to improve symptoms, reduce complications, and slow down the progression of the disease. An integrated approach that combines pharmacological agents, including immunosuppressants, endothelin receptor antagonists, and prostanoids, with nonpharmacological interventions such as physical and occupational therapy is essential for maximizing patient care.

Conclusion

Through the clarification of existing gaps in knowledge and identification of emerging trends, our goal is to improve the accuracy of diagnosis, enhance the effectiveness of therapeutic interventions, and ultimately enhance the overall quality of life for individuals suffering from scleroderma. Ongoing cooperation and creative research are necessary to advance the field and achieve improved patient outcomes and new therapeutic discoveries.

Therapeutic Approaches to Systemic Sclerosis: Recent Approvals and Future Candidate Therapies

Systemic sclerosis is the rheumatic disease with the highest individual mortality. The severity of the disease is determined by the extent of fibrotic changes to cutaneous and internal organ tissues, the most life-threatening visceral manifestations being interstitial lung disease, SSc-associated-pulmonary arterial hypertension and myocardial involvement. The heterogeneity of the disease has initially hindered the design of successful clinical trials, but considerations on classification criteria have improved patient selection in trials, allowing the identification of more homogeneous groups of patients based on progressive visceral manifestations or the extent of skin involvement with a focus of patients with early disease. Two major subsets of systemic sclerosis are classically described: limited cutaneous systemic sclerosis characterized by distal skin fibrosis and the diffuse subset with distal and proximal skin thickening. Beyond this dichotomic subgrouping of systemic sclerosis, new phenotypic considerations based on antibody subtypes have provided a better understanding of the heterogeneity of the disease, anti-Scl70 antibodies being associated with progressive interstitial lung disease regardless of cutaneous involvement. Two targeted therapies, tocilizumab (a monoclonal antibody targeting interleukin-6 receptors (IL-6R)) and nintedanib (a tyrosine kinase inhibitor), have recently been approved by the American Food & Drug Administration to limit the decline of lung function in patients with SSc-associated interstitial lung disease, demonstrating that such better understanding of the disease pathogenesis with the identification of key targets can lead to therapeutic advances in the management of some visceral manifestations of the disease. This review will provide a brief overview of the pathogenesis of SSc and will present a selection of therapies recently approved or evaluated in this context. Therapies evaluated and approved in SSc-ILD will be emphasized and a review of recent phase II trials in diffuse cutaneous systemic sclerosis will be proposed. We will also discuss selected therapeutic pathways currently under investigation in systemic sclerosis that still lack clinical data in this context but that may show promising results in the future based on preclinical data.

M2 macrophage polarization in systemic sclerosis fibrosis: pathogenic mechanisms and therapeutic effects

Systemic sclerosis (SSc, scleroderma), is an autoimmune rheumatic disease characterized by fibrosis of the skin and internal organs, and vasculopathy. Preventing fibrosis by targeting aberrant immune cells that drive extracellular matrix (ECM) over-deposition is a promising therapeutic strategy for SSc. Previous research suggests that M2 macrophages play an essential part in the fibrotic process of SSc. Targeted modulation of molecules that influence M2 macrophage polarization, or M2 macrophages, may hinder the progression of fibrosis. Here, in an effort to offer fresh perspectives on the management of scleroderma and fibrotic diseases, we review the molecular mechanisms underlying the regulation of M2 macrophage polarization in SSc-related organ fibrosis, potential inhibitors targeting M2 macrophages, and the mechanisms by which M2 macrophages participate in fibrosis.

Oxidative Stress and Epigenetics: miRNA Involvement in Rare Autoimmune Diseases

Autoimmune diseases (ADs) such as Sjögren’s syndrome, Kawasaki disease, and systemic sclerosis are characterized by chronic inflammation, oxidative stress, and autoantibodies, which cause joint tissue damage, vascular injury, fibrosis, and debilitation. Epigenetics participate in immune cell proliferation and differentiation, which regulates the development and function of the immune system, and ultimately interacts with other tissues. Indeed, overlapping of certain clinical features between ADs indicate that numerous immunologic-related mechanisms may directly participate in the onset and progression of these diseases. Despite the increasing number of studies that have attempted to elucidate the relationship between miRNAs and oxidative stress, autoimmune disorders and oxidative stress, and inflammation and miRNAs, an overall picture of the complex regulation of these three actors in the pathogenesis of ADs has yet to be formed. This review aims to shed light from a critical perspective on the key AD-related mechanisms by explaining the intricate regulatory ROS/miRNA/inflammation axis and the phenotypic features of these rare autoimmune diseases. The inflamma-miRs miR-155 and miR-146, and the redox-sensitive miR miR-223 have relevant roles in the inflammatory response and antioxidant system regulation of these diseases. ADs are characterized by clinical heterogeneity, which impedes early diagnosis and effective personalized treatment. Redox-sensitive miRNAs and inflamma-miRs can help improve personalized medicine in these complex and heterogeneous diseases.

Pulmonary Manifestations in Rheumatological Diseases

Pulmonary involvement complicates the various aspects of care in patients suffering from autoimmune disorders. The epidemiological data generated over the last 10 to 15 years have improved the overall understanding of the risk factors and pathophysiological mechanisms involved in pulmonary involvement in rheumatological conditions. Recent advances in genetics have provided superior insight into the pathogenesis of autoimmune diseases and the underlying pulmonary involvement. This review article provides a concise overview of the four most common rheumatological conditions associated with pulmonary involvement: systemic lupus erythematosus (SLE), dermatomyositis/polymyositis, rheumatoid arthritis (RA), and systemic sclerosis (SSc). The clinical, epidemiological, and genetic aspects of these diseases are summarized in this article with particular emphasis on the characteristic patterns of pulmonary involvement in radiological imaging and various treatment options for each of these autoimmune diseases and their lung manifestations.

Pathophysiology of systemic sclerosis (scleroderma)

Systemic sclerosis (scleroderma) is an autoimmune-triggered chronic fibrosing disease that affects the skin and many other organs. Its pathophysiology is complex and involves an early endothelial damage, an inflammatory infiltrate and a resulting fibrotic reaction. Based on a predisposing genetic background, an altered balance of the acquired and the innate immune system leads to the release of many cytokines and chemokines as well as autoantibodies, which induce the activation of fibroblasts with the formation of myofibroblasts and the deposition of a stiff and rigid connective tissue. A curative treatment is still not available but remarkable progress has been made in the management of organ complications. In addition, several breakthroughs in the pathophysiology have led to new therapeutic concepts. Based on these, many new compounds have been developed during the last years, which target these different pathways and offer specific therapeutic approaches.

Defective Early B Cell Tolerance Checkpoints in Patients With Systemic Sclerosis Allow the Production of Self Antigen-Specific Clones

OBJECTIVE

Early selection steps preventing autoreactive naive B cell production are often impaired in patients with autoimmune diseases, but central and peripheral B cell tolerance checkpoints have not been assessed in patients with systemic sclerosis (SSc). This study was undertaken to characterize early B cell tolerance checkpoints in patients with SSc.

METHODS

Using an in vitro polymerase chain reaction-based approach that allows the expression of recombinant antibodies cloned from single B cells, we tested the reactivity of antibodies expressed by 212 CD19+CD21low CD10+IgMhigh CD27- new emigrant/transitional B cells and 190 CD19+CD21+CD10-IgM+CD27- mature naive B cells from 10 patients with SSc.

RESULTS

Compared to serum from healthy donors, serum from patients with SSc displayed elevated proportions of polyreactive and antinuclear-reactive new emigrant/transitional B cells that recognize topoisomerase I, suggesting that defective central B cell tolerance contributes to the production of serum autoantibodies characteristic of the disease. Frequencies of autoreactive mature naive B cells were also significantly increased in SSc patients compared to healthy donors, thus indicating that a peripheral B cell tolerance checkpoint may be impaired in SSc.

CONCLUSION

Defective counterselection of developing autoreactive naive B cells in SSc leads to the production of self antigen-specific B cells that may secrete autoantibodies and allow the formation of immune complexes, which promote fibrosis in SSc.

Novel Concepts in Systemic Sclerosis Pathogenesis: Role for miRNAs

Systemic sclerosis (SSc) is a rare connective tissue disease with heterogeneous clinical phenotypes. It is characterized by the pathogenic triad: microangiopathy, immune dysfunction, and fibrosis. Epigenetic mechanisms modulate gene expression without interfering with the DNA sequence. Epigenetic marks may be reversible and their differential response to external stimuli could explain the protean clinical manifestations of SSc while offering the opportunity of targeted drug development. Small, non-coding RNA sequences (miRNAs) have demonstrated complex interactions between vasculature, immune activation, and extracellular matrices. Distinct miRNA profiles were identified in SSc skin specimens and blood samples containing a wide variety of dysregulated miRNAs. Their target genes are mainly involved in profibrotic pathways, but new lines of evidence also confirm their participation in impaired angiogenesis and aberrant immune responses. Research approaches focusing on earlier stages of the disease and on differential miRNA expression in various tissues could bring novel insights into SSc pathogenesis and validate the clinical utility of miRNAs as biomarkers and therapeutic targets.

Iloprost Attenuates Oxidative Stress-Dependent Activation of Collagen Synthesis Induced by Sera from Scleroderma Patients in Human Pulmonary Microvascular Endothelial Cells

Endothelial cell injury is an early event in systemic sclerosis (SSc) pathogenesis and several studies indicate oxidative stress as the trigger of SSc-associated vasculopathy. Here, we show that circulating factors present in sera of SSc patients increased reactive oxygen species (ROS) production and collagen synthesis in human pulmonary microvascular endothelial cells (HPMECs). In addition, the possibility that iloprost, a drug commonly used in SSc therapy, might modulate the above-mentioned biological phenomena has been also investigated. In this regard, as compared to sera of SSc patients, sera of iloprost-treated SSc patients failed to increased ROS levels and collagen synthesis in HPMEC, suggesting a potential antioxidant mechanism of this drug.

A Novel Insight into Endothelial and Cardiac Cells Phenotype in Systemic Sclerosis Using Patient-Derived Induced Pluripotent Stem Cell

OBJECTIVE

Systemic sclerosis (SSc) is a connective tissue disease associated with vascular damage and multi organ fibrotic changes with unknown pathogenesis. Most SSc patients suffer from defective angiogenesis/vasculogenesis and cardiac conditions leading to high mortality rates. We aimed to investigate the cardiovascular phenotype of SSc by cardiogenic differentiation of SSc induced pluripotent stem cells (iPSC).

MATERIALS AND METHODS

In this experimental study, we generated iPSC from two diffuse SSc patients, followed by successful differentiation into endothelial cells (ECs) and cardiomyocytes (CMs).

RESULTS

SSc-derived EC (SSc-EC) expressed KDR, a nearly EC marker, similar to healthy control-EC (C1-EC). After sorting and culturing KDR+ cells, the resulting EC expressed CD31, a late endothelial marker, but vascular endothelial (VE)-cadherin expression markedly dropped resulting in a functional defect as reflected in tube formation failure of SSc-EC. Interestingly, upregulation of SNAI1 (snail family transcriptional repressor 1) was observed in SSc-EC which might underlie VE-cadherin downregulation. Furthermore, SSc-derived CM (SSc-CM) successfully expressed cardiacspecific markers including ion channels, resulting in normal physiological behavior and responsiveness to cardioactive drugs.

CONCLUSION

This study provides an insight into impaired angiogenesis observed in SSc patients by evaluating in vitro cardiovascular differentiation of SSc iPSC.

Toward Understanding of Environmental Risk Factors in Systemic Sclerosis

IMPORTANCE

Systemic sclerosis (SSc) is a severe, chronic, and incurable autoimmune fibrotic skin disease with significant extracutaneous involvement. Low concordance rate in twin studies and unequal geographic distribution of SSc argues for importance of environment in disease initiation and progression.

OBJECTIVE

In this manuscript we provide a summary of all investigated potential external risk factors for SSc.

DATA SOURCES

A literature search in PubMed and EMBASE database was performed for studies published until January 1, 2020 by 2 reviewers (EN and LO) independently.

FINDINGS

Occupational and/or environmental exposures to silica and organic solvents are associated with increased incidence and severity of SSc. Exposure to epoxy resins, asbestos, and particulate air pollution favors increased risk of SSc, but data are based on limited number of observational studies. There is insufficient evidence to conclude an association between SSc development and other occupational (eg, welding fumes) or personal exposures (eg, smoking, vitamin D deficiency). Association of SSc with silicone breast implants has been disproven. Infectious pathogens (eg, Helicobacter pylori and angiotropic viruses) and dysbiosis seem to play a role in SSc development and severity, but their role remains to be clarified.

CONCLUSIONS AND RELEVANCE

It may be prudent to counsel our patients with SSc (or those at risk of SSc) to avoid occupations with exposure to silica, organic solvents, asbestos and epoxy resins; restraint from smoking, using cocaine or drugs with pro-fibrotic potential. While the association between low vitamin D and SSc remains to be confirmed, we believe that SSc patients should be encouraged to maintain healthy vitamin D levels as benefits outweigh the risks.

Mesenchymal stromal cells for systemic sclerosis treatment

Systemic sclerosis (SSc) is a rare chronic autoimmune disease characterized by vasculopathy, dysregulation of innate and adaptive immune responses, and progressive fibrosis. SSc remains an orphan disease, with high morbity and mortality in SSc patients. The mesenchymal stromal cells (MSC) demonstrate in vitro and in vivo pro-angiogenic, immuno-suppressive, and anti-fibrotic properties and appear as a promising stem cell therapy type, that may target the key pathological features of SSc disease. This review aims to summarize acquired knowledge in the field of :1) MSC definition and in vitro and in vivo functional properties, which vary according to the donor type (allogeneic or autologous), the tissue sources (bone marrow, adipose tissue or umbilical cord) or inflammatory micro-environment in the recipient; 2) preclinical studies in various SSc animal models , which showed reduction in skin and lung fibrosis after MSC infusion; 3) first clinical trials in human, with safety and early efficacy results reported in SSc patients or currently tested in several ongoing clinical trials.

MicroRNA-320a: an important regulator in the fibrotic process in interstitial lung disease of systemic sclerosis

Background

Systemic sclerosis (SSc) is an acquired autoimmune disorder characterized by excessive accumulation of collagen and progressive tissue fibrosis. Although interstitial lung disease (ILD) complicates the majority of SSc patients and is the leading cause of death, its pathogenesis remains largely unclear. In the current study, we aimed to evaluate the role of microRNAs in SSc-ILD.

Methods

miRNA expression patterns were assessed by miRNA array and real-time PCR from serum and PBMCs of SSc-ILD patients and healthy controls. Bleomycin-induced SSc-ILD mouse model was used to verify the miRNA expression in the lung tissue. The function of miRNAs in pulmonary fibroblasts was assessed using miRNA inhibitors, and mimics.

Results

miR-320a was significantly downregulated in both SSc-ILD patients and mouse models. The inhibition or overexpression of miR-320a in human pulmonary fibroblasts significantly affected the protein expression of type I collagen. Luciferase reporter assay, RT-PCR, and western blot analysis identified TGFBR2 and IGF1R as direct targets of miR-320a. Upon TGF-β stimulation, the expression of miR-320a and collagen genes were significantly upregulated.

Conclusion

miR-320a, together with its target genes, TGFBR2 and IGF1R, constituted a complex regulatory network, and played an important role in the fibrotic process of SSc-ILD. Investigation of more detailed mechanisms of miR-320a-mediated regulation of collagen expression may provide new therapeutic strategies for SSc-ILD.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13075-020-02411-9.

Relating Interferon Regulatory Factor 5 Rs2004640 Gene Polymorphism To Increased Risk Of Systemic Sclerosis In The Patients: Russian Federation Cohort

Background ― A number of studies confirmed a crucial role of type 1 interferon in pathophysiology of connective tissue diseases. Interferon regulatory factors (IRF) coordinate an expression of type 1 interferon, while interferon regulatory factor 5 (IRF5) gene was recently identified as causing predisposition to systemic lupus erythematosus and Sjögren syndrome. The objective of our study was to identify possible association of IRF5 rs2004640 (G/T) single nucleotide polymorphism with systemic sclerosis (SSc). Material and Methods―The study involved 236 individuals, including 105 patients with SSc diagnosis and 131 control individuals from Moscow region. The latter were healthy, unrelated to each other, their genders and ages were matched to those of SSc patients. Allele-specific real-time polymerase chain reaction (PCR) was used to study IFR5 rs2004640 polymorphism. Results ― We detected significantly higher percentage of IRF5 T-allele carriers in all patients (59.5%), those with diffuse cutaneous SSc (67.3%), patients with interstitial lung lesions (62.3%), and those with positive titers of anti-topoisomerase I antibodies (66.3%), compared with control group (46.2%). The odds ratios (OR) were: 1.71 (р=0.00), 2.40 (р=0.0004), 1.93 (р=0.002), and 2.30 (р=0.0008), correspondingly. Conclusion ― The replacement of nucleotide G by T in the IRF5 rs2004640 gene polymorphism was associated with a predisposition to SSc. Our data implied an existence of a novel SSc pathogenetic pathway associated with important role of type 1 interferon in pathophysiology of connective tissue diseases.

Chromatin accessibility landscapes of skin cells in systemic sclerosis nominate dendritic cells in disease pathogenesis

Systemic sclerosis (SSc) is a disease at the intersection of autoimmunity and fibrosis. However, the epigenetic regulation and the contributions of diverse cell types to SSc remain unclear. Here we survey, using ATAC-seq, the active DNA regulatory elements of eight types of primary cells in normal skin from healthy controls, as well as clinically affected and unaffected skin from SSc patients. We find that accessible DNA elements in skin-resident dendritic cells (DCs) exhibit the highest enrichment of SSc-associated single-nucleotide polymorphisms (SNPs) and predict the degrees of skin fibrosis in patients. DCs also have the greatest disease-associated changes in chromatin accessibility and the strongest alteration of cell-cell interactions in SSc lesions. Lastly, data from an independent cohort of patients with SSc confirm a significant increase of DCs in lesioned skin. Thus, the DCs epigenome links inherited susceptibility and clinically apparent fibrosis in SSc skin, and can be an important driver of SSc pathogenesis.

Exome-Wide Association Analysis Suggests LRP2BP as a Susceptibility Gene for Endothelial Injury in Systemic Sclerosis in the Han Chinese Population

Genetic factors play a key role in the pathogenesis of autoimmune diseases, whereas the disease-causing variants remain largely unknown. Herein, we performed an exome-wide association study of systemic sclerosis in a Han Chinese population. In the discovery stage, 527 patients with systemic sclerosis and 5,024 controls were recruited and genotyped. In the validation study, an independent sample set of 479 patients and 1,096 controls were examined. In total, we found that four independent signals reached genome-wide significance. Among them, rs7574865 (P_combined = 3.87 × 10^-12) located within signal transducer and activator of transcription 4 gene was identified previously using samples of European ancestry. Additionally, another signal including three SNPs in linkage disequilibrium might be unreported susceptibility loci located in the epidermis differentiation complex region. Furthermore, two SNPs located within exon 3 of IGHM (rs45471499, P_combined = 1.15 × 10^-9) and upstream of LRP2BP (rs4317244, P_combined = 4.17 × 10^-8) were found. Moreover, rs4317244 was identified as an expression quantitative trait locus for LRP2BP that regulates tight junctions, cell cycle, and apoptosis in endothelial cell lines. Collectively, our results revealed three signals associated with systemic sclerosis in Han Chinese and suggested the importance of LRP2BP in systemic sclerosis pathogenesis. Given the limited sample size and discrepancies between previous results and our study, further studies in multiethnic populations are required for verification.

Chemical exposure-induced systemic fibrosing disorders: Novel insights into systemic sclerosis etiology and pathogenesis

Numerous drugs and chemical substances are capable of inducing exaggerated tissue fibrotic responses. The vast majority of these agents cause localized fibrotic tissue reactions or fibrosis confined to specific organs. Although much less frequent, chemically-induced systemic fibrotic disorders have been described, sometimes occurring as temporally confined outbreaks. These include the Toxic Oil Syndrome (TOS), the Eosinophilia-Myalgia Syndrome (EMS), and Nephrogenic Systemic Fibrosis (NSF). Although each of these disorders displays some unique characteristics, they all share crucial features with Systemic Sclerosis (SSc), the prototypic idiopathic systemic fibrotic disease, including vasculopathy, chronic inflammatory cell infiltration of affected tissues, and cutaneous and visceral tissue fibrosis. The study of the mechanisms and molecular alterations involved in the development of the chemically-induced systemic fibrotic disorders has provided valuable clues that may allow elucidation of SSc etiology and pathogenesis. Here, we review relevant aspects of the TOS, EMS, and NSF epidemic outbreaks of chemically-induced systemic fibrosing disorders that provide strong support to the hypothesis that SSc is caused by a toxic or biological agent that following its internalization by endothelial cells induces in genetically predisposed individuals a series of molecular alterations that result in the development of SSc clinical and pathological alterations.

CXCL4 Links Inflammation and Fibrosis by Reprogramming Monocyte-Derived Dendritic Cells in vitro

Fibrosis is a condition shared by numerous inflammatory diseases. Our incomplete understanding of the molecular mechanisms underlying fibrosis has severely hampered effective drug development. CXCL4 is associated with the onset and extent of fibrosis development in multiple inflammatory and fibrotic diseases. Here, we used monocyte-derived cells as a model system to study the effects of CXCL4 exposure on dendritic cell development by integrating 65 longitudinal and paired whole genome transcriptional and methylation profiles. Using data-driven gene regulatory network analyses, we demonstrate that CXCL4 dramatically alters the trajectory of monocyte differentiation, inducing a novel pro-inflammatory and pro-fibrotic phenotype mediated via key transcriptional regulators including CIITA. Importantly, these pro-inflammatory cells directly trigger a fibrotic cascade by producing extracellular matrix molecules and inducing myofibroblast differentiation. Inhibition of CIITA mimicked CXCL4 in inducing a pro-inflammatory and pro-fibrotic phenotype, validating the relevance of the gene regulatory network. Our study unveils that CXCL4 acts as a key secreted factor driving innate immune training and forming the long-sought link between inflammation and fibrosis.

The Pathogenesis of Systemic Sclerosis: An Understanding Based on a Common Pathologic Cascade across Multiple Organs and Additional Organ-Specific Pathologies

Systemic sclerosis (SSc) is a multisystem autoimmune and vascular disease resulting in fibrosis of various organs with unknown etiology. Accumulating evidence suggests that a common pathologic cascade across multiple organs and additional organ-specific pathologies underpin SSc development. The common pathologic cascade starts with vascular injury due to autoimmune attacks and unknown environmental factors. After that, dysregulated angiogenesis and defective vasculogenesis promote vascular structural abnormalities, such as capillary loss and arteriolar stenosis, while aberrantly activated endothelial cells facilitate the infiltration of circulating immune cells into perivascular areas of various organs. Arteriolar stenosis directly causes pulmonary arterial hypertension, scleroderma renal crisis and digital ulcers. Chronic inflammation persistently activates interstitial fibroblasts, leading to the irreversible fibrosis of multiple organs. The common pathologic cascade interacts with a variety of modifying factors in each organ, such as keratinocytes and adipocytes in the skin, esophageal stratified squamous epithelia and myenteric nerve system in gastrointestinal tract, vasospasm of arterioles in the heart and kidney, and microaspiration of gastric content in the lung. To better understand SSc pathogenesis and develop new disease-modifying therapies, it is quite important to understand the complex pathogenesis of SSc from the two distinct perspectives, namely the common pathologic cascade and additional organ-specific pathologies.

Genetic Susceptibility to Systemic Sclerosis in the Greek-Cypriot Population: A Pilot Study

Background: Systemic Sclerosis (SSc), also known as scleroderma, is an autoimmune rheumatic disease, which is clinically subdivided into two major subgroups; limited (lcSSc) and diffuse cutaneous scleroderma (dcSSc). Even though the SSc etiologies remains unclear, some HLA and non-HLA genetic variants have been associated with the disease. Aim: This study was designed to evaluate the associations between several HLA-related genetic variants and SSc in the Greek-Cypriot population. Methods: Forty-one SSc patients and 164 controls were genotyped at 18 selected single nucleotide polymorphisms (SNPs) using restriction fragment length polymorphism analyses, Sanger sequencing, and a multiplex SNaPshot minisequencing assay. Logistic regression analysis under the log-additive model was used to evaluate all possible associations between these SNPs and SSc; nominal statistical significance was assumed at p < 0.05. Results: Associations of SSc with SNPs rs3117230, rs3128930, and rs3128965 within the HLA-DPB1 and HLA-DPB2 regions were observed in the Greek-Cypriot population at the level of p < 0.05. However, none of these associations survived a Bonferroni correction. The direction of the effect is consistent with the direction reported in previous studies. In addition, allele frequencies of the majority of the selected SNPs in the Greek-Cypriot population are similar to those reported in the European population. Conclusion: This study initiates the genetic investigation of SSc in the Greek-Cypriot population, a relatively small newly investigated population. Further investigation with a larger sample size and/or additional SSc susceptibility loci may confirm the association of some of these variants with SSc in the Greek-Cypriot population that could potentially be used for predictive testing.

Role of microRNA in the pathogenesis of systemic sclerosis tissue fibrosis and vasculopathy

Systemic Sclerosis (SSc) pathogenesis involves multiple immunological, vascular and fibroproliferative abnormalities that contribute to a severe and complex clinical picture. Vasculopathy and fibroproliferative alterations are two hallmark pathological processes in SSc that are responsible for the most severe clinical manifestations of the disease and determine its clinical outcome and mortality. However, the pathogenesis of SSc vasculopathy and of the uncontrolled SSc fibrotic process remain incompletely understood. Recent investigations into the molecular pathways involved in these processes have identified an important role for epigenetic processes that contribute to overall disease progression and have emphasized microRNAs (miRNAs) as crucial epigenetic regulators. MiRNAs hold unique potential for elucidating SSc pathogenesis, improving diagnosis and developing effective targeted therapies for the disease. This review examines the important role that miRNAs play in the development and regulation of vascular and fibroproliferative alterations associated with SSc pathogenesis and their possible participation in the establishment of pathogenetic connections between these two processes. This review also emphasizes that further understanding of the involvement of miRNA in SSc fibrosis and vasculopathy will very likely provide novel future research directions and allow for the identification of groundbreaking therapeutic interventions within these processes. MiR-21, miR- 31, and miR-155 are of particular interest owing to their important involvement in both SSc vasculopathy and fibroproliferative alterations.

New insights into the genetics and epigenetics of systemic sclerosis

Systemic sclerosis (SSc) is a severe autoimmune disease that is characterized by vascular abnormalities, immunological alterations and fibrosis of the skin and internal organs. The results of genetic studies in patients with SSc have revealed statistically significant genetic associations with disease manifestations and progression. Nevertheless, genetic susceptibility to SSc is moderate, and the functional consequences of genetic associations remain only partially characterized. A current hypothesis is that, in genetically susceptible individuals, epigenetic modifications constitute the driving force for disease initiation. As epigenetic alterations can occur years before fibrosis appears, these changes could represent a potential link between inflammation and tissue fibrosis. Epigenetics is a fast-growing discipline, and a considerable number of important epigenetic studies in SSc have been published in the past few years that span histone post-translational modifications, DNA methylation, microRNAs and long non-coding RNAs. This Review describes the latest insights into genetic and epigenetic contributions to the pathogenesis of SSc and aims to provide an improved understanding of the molecular pathways that link inflammation and fibrosis. This knowledge will be of paramount importance for the development of medicines that are effective in treating or even reversing tissue fibrosis.

An Allele-Specific Functional SNP Associated with Two Systemic Autoimmune Diseases Modulates IRF5 Expression by Long-Range Chromatin Loop Formation

Both systemic lupus erythematosus (SLE) and systemic sclerosis (SSc) are autoimmune diseases sharing similar genetic backgrounds. Genome-wide association studies have constantly disclosed numerous genetic variants conferring to both disease risks at 7q32.1, but the functional mechanisms underlying them are still largely unknown. Through a series of bioinformatics and functional analyses, we prioritized a potential independent functional single-nucleotide polymorphism (rs13239597) within TNPO3 promoter region, residing in a putative enhancer element and validated that IRF5 is the distal target gene (∼118 kb) of rs13239597, which is a key regulator involved in pathogenic autoantibody dysregulation, increasing risk of both SLE and SSc. We experimentally validated the long-range chromatin interactions between rs13239597 and IRF5 using chromosome conformation capture assay. We further demonstrated that rs13239597-A acted as an allele-specific enhancer regulating IRF5 expression, independently of TNPO3 by using dual-luciferase reporter assays and CRISPR-Cas9. Particularly, the transcription factor EVI1 could preferentially bind to rs13239597-A allele and increase the enhancer activity to regulate IRF5 expression. Taken together, our results uncovered a mechanistic insight of a noncoding functional variant acting as an allele-specific distal enhancer to directly modulate IRF5 expression, which might obligate in understanding of complex genetic architectures of SLE and SSc pathogenesis.

Molecular Mechanisms of Epigenetic Regulators as Activatable Targets in Cancer Theranostics

Epigenetics is defined as somatically inheritable changes that are not accompanied by alterations in DNA sequence. Epigenetics encompasses DNA methylation, covalent histone modifications, non-coding RNA as well as nucleosome remodeling. Notably, abnormal epigenetic changes play a critical role in cancer development including malignant transformation, metastasis, prognosis, drug resistance and tumor recurrence, which can provide effective targets for cancer prognosis, diagnosis and therapy. Understanding these changes provide effective means for cancer diagnosis and druggable targets for better clinical applications. Histone modifications and related enzymes have been found to correlate well with cancer incidence and prognosis in recent years. Dysregulated expression or mutation of histone modification enzymes and histone modification status abnormalities have been considered to play essential roles in tumorigenesis and clinical outcomes of cancer treatment. Some of the histone modification inhibitors have been extensively employed in clinical practice and many others are still under laboratory research or pre-clinical assessment. Here we summarize the important roles of epigenetics, especially histone modifications in cancer diagnostics and therapeutics, and also discuss the developmental implications of activatable epigenetic targets in cancer theranostics.

Comparison of the clinical phenotype of systemic sclerosis patients in Iran and France in two university centers

OBJECTIVES

Systemic sclerosis is a severe and rare chronic auto-immune multisystem disorder characterized by vasculopathy and skin stiffness. Ethnic and geographical origin can influence the outcomes. In this study, we compared the phenotypic characteristics of Iranian and French patients.

METHODS

This cross-sectional study was performed on 200 Iranian and 268 French systemic sclerosis patients. Iranian patients collected from the Iranian systemic sclerosis cohort of the Rheumatology Research Center, Shariati hospital, Tehran University of Medical Sciences. The French population was monocentric, and it was constituted by the patients included locally in the EUSTAR database in December 2016.

RESULTS

The mean age at onset was significantly lower in Iranian patients (35.58 ± 11.68 vs 47.06 ± 13.54, p-value < 0.001). The female-to-male ratio was approximately 5.2:1 and was not different in the two populations. The prevalence of diffuse cutaneous systemic sclerosis was significantly higher in Iranian patients (60.2% vs 42.85%, p-value < 0.001). Calcinosis cutis and joint synovitis were more prevalent in French patients (p-value = 0.013, <0.001). The positivity of anti-topoisomerase antibody was higher in Iranian patients, whereas the anti-centromere antibody predominated in French cases (p-value < 0.001). Restrictive pattern of pulmonary function test was more common in Iranian patients (p-value < 0.001), while estimated pulmonary arterial pressure by echocardiography was higher in French patients (p-value < 0.001).

CONCLUSION

It seems that systemic sclerosis occurred in younger ages among Iranian female with the predominance of diffuse cutaneous subtype. In addition, lung interstitial disease appeared to be more prevalent and severe in Iranians than French patients.

Compendium of skin molecular signatures identifies key pathological features associated with fibrosis in systemic sclerosis

OBJECTIVES

Treatment of patients with systemic sclerosis (SSc) can be challenging because of clinical heterogeneity. Integration of genome-scale transcriptomic profiling for patients with SSc can provide insights on patient categorisation and novel drug targets.

METHODS

A normalised compendium was created from 344 skin samples of 173 patients with SSc, covering an intersection of 17 424 genes from eight data sets. Differentially expressed genes (DEGs) identified by three independent methods were subjected to functional network analysis, where samples were grouped using non-negative matrix factorisation. Finally, we investigated the pathways and biomarkers associated with skin fibrosis using gene-set enrichment analysis.

RESULTS

We identified 1089 upregulated DEGs, including 14 known genetic risk factors and five potential drug targets. Pathway-based subgrouping revealed four distinct clusters of patients with SSc with distinct activity signatures for SSc-relevant pathways. The inflammatory subtype was related to significant improvement in skin fibrosis at follow-up. The phosphoinositide-3-kinase-protein kinase B (PI3K-Akt) signalling pathway showed both the closest correlation and temporal pattern to skin fibrosis score. COMP, THBS1, THBS4, FN1, and TNC were leading-edge genes of the PI3K-Akt pathway in skin fibrogenesis.

CONCLUSIONS

Construction and analysis of normalised skin transcriptomic compendia can provide useful insights on pathway involvement by SSc subsets and discovering viable biomarkers for a skin fibrosis index. Particularly, the PI3K-Akt pathway and its leading players are promising therapeutic targets.

Wong G, Chizzolini C, Frasca L. CXCL4 assembles DNA into liquid crystalline complexes to amplify TLR9-mediated interferon-α production in systemic sclerosis

Systemic sclerosis (SSc) is a chronic autoimmune disease characterized by fibrosis and vasculopathy. CXCL4 represents an early serum biomarker of severe SSc and likely contributes to inflammation via chemokine signaling pathways, but the exact role of CXCL4 in SSc pathogenesis is unclear. Here, we elucidate an unanticipated mechanism for CXCL4-mediated immune amplification in SSc, in which CXCL4 organizes "self" and microbial DNA into liquid crystalline immune complexes that amplify TLR9-mediated plasmacytoid dendritic cell (pDC)-hyperactivation and interferon-α production. Surprisingly, this activity does not require CXCR3, the CXCL4 receptor. Importantly, we find that CXCL4-DNA complexes are present in vivo and correlate with type I interferon (IFN-I) in SSc blood, and that CXCL4-positive skin pDCs coexpress IFN-I-related genes. Thus, we establish a direct link between CXCL4 overexpression and the IFN-I-gene signature in SSc and outline a paradigm in which chemokines can drastically modulate innate immune receptors without being direct agonists.

Histone modifications underlie monocyte dysregulation in patients with systemic sclerosis, underlining the treatment potential of epigenetic targeting

BACKGROUND AND OBJECTIVE

Systemic sclerosis (SSc) is a severe autoimmune disease, in which the pathogenesis is dependent on both genetic and epigenetic factors. Altered gene expression in SSc monocytes, particularly of interferon (IFN)-responsive genes, suggests their involvement in SSc development. We investigated the correlation between epigenetic histone marks and gene expression in SSc monocytes.

METHODS

Chromatin immunoprecipitation followed by sequencing (ChIPseq) for histone marks H3K4me3 and H3K27ac was performed on monocytes of nine healthy controls and 14 patients with SSc. RNA sequencing was performed in parallel to identify aberrantly expressed genes and their correlation with the levels of H3K4me3 and H3K27ac located nearby their transcription start sites. ChIP-qPCR assays were used to verify the role of bromodomain proteins, H3K27ac and STATs on IFN-responsive gene expression.

RESULTS

1046 and 534 genomic loci showed aberrant H3K4me3 and H3K27ac marks, respectively, in SSc monocytes. The expression of 381 genes was directly and significantly proportional to the levels of such chromatin marks present near their transcription start site. Genes correlated to altered histone marks were enriched for immune, IFN and antiviral pathways and presented with recurrent binding sites for IRF and STAT transcription factors at their promoters. IFNα induced the binding of STAT1 and STAT2 at the promoter of two of these genes, while blocking acetylation readers using the bromodomain BET family inhibitor JQ1 suppressed their expression.

CONCLUSION

SSc monocytes have altered chromatin marks correlating with their IFN signature. Enzymes modulating these reversible marks may provide interesting therapeutic targets to restore monocyte homeostasis to treat or even prevent SSc.

Unmet Needs in Systemic Sclerosis Understanding and Treatment: the Knowledge Gaps from a Scientist's, Clinician's, and Patient's Perspective

Systemic sclerosis (SSc) is a highly heterogeneous disease caused by a complex molecular circuitry. For decades, clinical and molecular research focused on understanding the primary process of fibrosis. More recently, the inflammatory, immunological and vascular components that precede the actual onset of fibrosis, have become a matter of increasing scientific scrutiny. As a consequence, the field has started to realize that the early identification of this syndrome is crucial for optimal clinical care as well as for understanding its pathology. The cause of SSc cannot be appointed to a single molecular pathway but to a multitude of molecular aberrances in a spatial and temporal matter and on the backbone of the patient's genetic predisposition. These alterations underlie the plethora of signs and symptoms which patients experience and clinicians look for, ultimately culminating in fibrotic features. To solve this complexity, a close interaction among the patient throughout its "journey," the clinician through its clinical assessments and the researcher with its experimental design, seems to be required. In this review, we aimed to highlight the features of SSc through the eyes of these three professionals, all with their own expertise and opinions. With this unique setup, we underscore the importance of investigating the role of environmental factors in the onset and perpetuation of SSc, of focusing on the earliest signs and symptoms preceding fibrosis and on the application of holistic research approaches that include a multitude of potential molecular alterations in time in an unbiased fashion, in the search for a patient-tailored cure.

Survival rate, causes of death, and risk factors in systemic sclerosis: a large cohort study

To investigate the clinical pattern, survival rate, causes of death and risk factors in a large cohort of Chinese Han patients with systemic sclerosis (SSc). Inpatients treated from 2002 to 2014 were included in this study. Patients were classified into diffuse cutaneous SSc (dcSSc), limited cutaneous SSc (lcSSc), and SSc-overlap syndrome groups. Data were analyzed using Chi-squared tests, Kaplan-Meier curves, log-rank tests, and Cox proportional hazards modeling. Among a total of 201 patients, dcSSc (50.2%) was the major subtype, followed by lcSSc (30.3%) and SSc-overlap (19.4%). Interstitial lung disease (ILD, 148/201, 74%) was the most frequent organ involvement. The overall survival rates were 98% and 95% at 5 and 10 years, respectively. The overall standard mortality ratio (SMR) was 2.22. The most common cause of death was ILD combined with infection (8/16, 50%), followed by kidney failure (2/16, 12.5%). On crude analysis, pulmonary hypertension, ILD, cardiac involvements, renal involvements, and digital ischemia were associated with poor prognosis. On multivariate analysis, pericardial effusion (p = 0.000) and digital ischemia (p = 0.016) were independent prognostic factors of death. The mortality rate of patients with SSc is mildly increased in comparison with the general population. ILD is the most common systemic involvement and the principal cause of death in SSc. Pericardial effusion and digital ischemia are independent factors associated with death.

Integration of Genome-Wide DNA Methylation and Transcription Uncovered Aberrant Methylation-Regulated Genes and Pathways in the Peripheral Blood Mononuclear Cells of Systemic Sclerosis

Objective. Systemic sclerosis (SSc) is a systemic connective tissue disease of unknown etiology. Aberrant gene expression and epigenetic modifications in circulating immune cells have been implicated in the pathogenesis of SSc. This study is to delineate the interaction network between gene transcription and DNA methylation in PBMC of SSc patients and to identify methylation-regulated genes which are involved in the pathogenesis of SSc. Methods. Genome-wide mRNA transcription and global DNA methylation analysis were performed on PBMC from 18 SSc patients and 19 matched normal controls (NC) using Illumina BeadChips. Differentially expressed genes (DEGs) and differentially methylated positions (DMPs) were integrative analyzed to identify methylation-regulated genes and associated molecular pathways. Results. Transcriptome analysis distinguished 453 DEGs (269 up- and 184 downregulated) in SSc from NC. Global DNA methylation analysis identified 925 DMPs located on 618 genes. Integration of the two lists revealed only 20 DEGs which harbor inversely correlated DMPs, including 12 upregulated (ELANE, CTSG, LTBR, C3AR1, CSTA, SPI1, ODF3B, SAMD4A, PLAUR, NFE2, ZYX, and CTSZ) and eight downregulated genes (RUNX3, PRF1, PRKCH, PAG1, RASSF5, FYN, CXCR6, and F2R). These potential methylation-regulated DEGs (MeDEGs) are enriched in the pathways related to immune cell migration, proliferation, activation, and inflammation activities. Using a machine learning algorism, we identified six out of the 20 MeDEGs, including F2R, CXCR6, FYN, LTBR, CTSG, and ELANE, which distinguished SSc from NC with 100% accuracy. Four genes (F2R, FYN, PAG1, and PRKCH) differentially expressed in SSc with interstitial lung disease (ILD) compared to SSc without ILD. Conclusion. The identified MeDEGs may represent novel candidate factors which lead to the abnormal activation of immune regulatory pathways in the pathogenesis of SSc. They may also be used as diagnostic biomarkers for SSc and clinical complications.

CCL21 as a Potential Serum Biomarker for Pulmonary Arterial Hypertension in Systemic Sclerosis

OBJECTIVE

Systemic sclerosis (SSc) is a major cause of pulmonary arterial hypertension (PAH). Murine models indicate key roles for chemokines CCL19 and CCL21 and their receptor CCR7 in lung inflammation leading to PAH. The objective of this study was to assess the chemokine CCL19-CCL21 axis in patients with SSc-related PAH.

METHODS

Serum samples obtained from 2 independent prospective SSc cohorts (n = 326), patients with idiopathic PAH (n = 12), and healthy control subjects (n = 100) were analyzed for CCL19/CCL21 levels, by enzyme-linked immunosorbent assay. The levels were defined as either high or low, using the mean + 2 SD value in controls as the cutoff value. Risk stratification at the time of PAH diagnosis and PAH-related events were performed. Descriptive and Cox regression analyses were conducted.

RESULTS

CCL21 levels were higher in patients with SSc compared with controls and were elevated prior to the diagnosis of PAH. PAH was more frequent in patients with high CCL21 levels (≥0.4 ng/ml) than in those with low CCL21 levels (33.3% versus 5.3% [P < 0.001]). In multivariate analyses, CCL21 was associated with PAH (hazard ratio [HR] 5.1, 95% CI 2.39-10.76 [P < 0.001]) and occurrence of PAH-related events (HR 4.7, 95% CI 2.12-10.46, P < 0.001). Risk stratification at the time of PAH diagnosis alone did not predict PAH-related events. However, when risk at diagnosis was combined with high or low CCL21 level, there was a significant predictive effect (HR 1.3, 95% CI 1.03-1.60 [P = 0.027]). A high CCL21 level was associated with decreased survival (P < 0.001).

CONCLUSION

CCL21 appears to be a promising marker for predicting the risk of SSc-related PAH and PAH progression. CCL21 may be part of a dysregulated immune pathway linked to the development of lung vascular damage in SSc.

Lung Involvements in Rheumatic Diseases: Update on the Epidemiology, Pathogenesis, Clinical Features, and Treatment

Lung illness encountered in patients with rheumatic diseases bears clinical significance in terms of increased morbidity and mortality as well as potential challenges placed on patient care. Although our understanding of natural history of this important illness is still limited, epidemiologic knowledge has been accumulated during the past decade to provide useful information on the risk factors and prognosis of lung involvements in rheumatic diseases. Moreover, the pathogenesis particularly in the context of genetics has been greatly updated for both the underlying rheumatic disease and associated lung involvement. This review will focus on the current update on the epidemiologic and genetics features and treatment options of the lung involvements associated with four major rheumatic diseases (rheumatoid arthritis, systemic sclerosis, myositis, and systemic lupus erythematosus), with more attention to a specific form of involvement or interstitial lung disease.

What can we learn from Fli1-deficient mice, new animal models of systemic sclerosis?

Systemic sclerosis is a complex multifactorial disease characterized by autoimmunity, vasculopathy, and selective organ fibrosis. A series of genetic and epidemiological studies have demonstrated that environmental influences play a central role in the onset of systemic sclerosis, while genetic factors determine the susceptibility to and the severity of this disease. Therefore, the identification of predisposing factors related to environmental influences would provide us with an informative clue to better understand the pathological process of this disease. Based on this concept, the deficiency of transcription factor Friend leukemia virus integration 1, which is epigenetically suppressed in systemic sclerosis, seems to be a potential candidate acting as the predisposing factor of this disease. Indeed, Fli1-mutated mice serve as a set of useful disease models to disclose the complex pathology of systemic sclerosis. This article overviews the recent advancement in systemic sclerosis animal models associated with Friend leukemia virus integration 1 deficiency.

Serum microRNA screening and functional studies reveal miR-483-5p as a potential driver of fibrosis in systemic sclerosis

OBJECTIVE

MicroRNAs (miRNAs) are regulatory molecules, which have been addressed as potential biomarkers and therapeutic targets in rheumatic diseases. Here, we investigated the miRNA signature in the serum of systemic sclerosis (SSc) patients and we further assessed their expression in early stages of the disease.

METHODS

The levels of 758 miRNAs were evaluated in the serum of 26 SSc patients as compared to 9 healthy controls by using an Openarray platform. Three miRNAs were examined in an additional cohort of 107 SSc patients and 24 healthy donors by single qPCR. MiR-483-5p expression was further analysed in the serum of patients with localized scleroderma (LoS) (n = 22), systemic lupus erythematosus (SLE) (n = 33) and primary Sjögren's syndrome (pSS) (n = 23). The function of miR-483-5p was examined by transfecting miR-483-5p into primary human dermal fibroblasts and pulmonary endothelial cells.

RESULTS

30 miRNAs were significantly increased in patients with SSc. Of these, miR-483-5p showed reproducibly higher levels in an independent SSc cohort and was also elevated in patients with preclinical-SSc symptoms (early SSc). Notably, miR-483-5p was not differentially expressed in patients with SLE or pSS, whereas it was up-regulated in LoS, indicating that this miRNA could be involved in the development of skin fibrosis. Consistently, miR-483-5p overexpression in fibroblasts and endothelial cells modulated the expression of fibrosis-related genes.

CONCLUSIONS

Our findings showed that miR-483-5p is up-regulated in the serum of SSc patients, from the early stages of the disease onwards, and indicated its potential function as a fine regulator of fibrosis in SSc.

Dendritic cells in systemic sclerosis: Advances from human and mice studies

Systemic sclerosis (SSc) is a complex heterogeneous fibrotic autoimmune disease with an unknown exact etiology, and characterized by three hallmarks: fibrosis, vasculopathy, and immune dysfunction. Dendritic cells (DCs) are specialized cells in pathogen sensing with high potency of antigen presentation and capable of releasing mediators to shape the immune response. Altered DCs distributions and their impaired functions may account for their role in breaking the immune tolerance and driving inflammation in SSc, and the direct contribution of DCs in promoting endothelial dysfunction and fibrotic process has only begun to be understood. Plasmacytoid dendritic cells in particular have been implicated due to their high production of type I interferon as well as other cytokines and chemokines, including the pro-inflammatory and anti-angiogenic CXCL4. Furthermore, a deeper understanding of human and mouse DC biology has clarified their identification and function in different tissues, and novel DC subsets have only recently been discovered. In this review, we highlight key findings and recent advances exploring DC role in the pathogenesis of SSc and other related autoimmune diseases, and consideration of their potential use as targeted therapy in SSc.

Sarcoidosis and Systemic Sclerosis: Strange Bedfellows

Coexistence of systemic sclerosis and sarcoidosis is rare. Both have predominant lung manifestations, each with distinctive features on computed tomography (CT) of the chest. We present herein a 52-year-old male with limited systemic sclerosis manifested primarily by sclerodactyly and subsequently by shortness of breath. A series of CT scans of the chest were reviewed. Initial CT chest one year prior to sclerodactyly onset revealed bilateral hilar and right paratracheal, prevascular, and subcarinal adenopathy. Five-year follow-up demonstrated thin-walled cysts, mediastinal lymphadenopathy, and nonspecific nodules. Due to progression of dyspnea, follow-up CT chest after one year again demonstrated multiple cysts with peripheral nodularity and subpleural nodules, but no longer with hilar or mediastinal adenopathy. Diagnostic open lung biopsy was significant for noncaseating granulomas suggestive of sarcoidosis. This is the first known case of a patient with systemic sclerosis diagnosed with sarcoidosis through lung biopsy without radiographic evidence of hilar or mediastinal lymphadenopathy at the time of biopsy. A review of cases of concomitant sarcoidosis and systemic sclerosis is discussed, including the pathophysiology of each disease with shared pathways leading to the development of both conditions in one patient.