Systemic sclerosis

Aptamer proteomics of serum exosomes from patients with Primary Raynaud's and patients with Raynaud's at risk of evolving into Systemic Sclerosis

BACKGROUND

A major unmet need for Systemic Sclerosis (SSc) clinical management is the lack of biomarkers for the early diagnosis of patients with Raynaud's Phenomenon at high risk of evolving into SSc.

OBJECTIVE

To identify proteins contained within serum exosomes employing an aptamer proteomic analysis that may serve to reveal patients with Raynaud's Phenomenon at risk of developing SSc.

METHODS

Exosomes were isolated from serum samples from patients with Primary Raynaud's Phenomenon and from patients with Raynaud's Phenomenon harbouring serum antinuclear antibodies (ANA) who may be at high risk of evolving into SSc. The expression of 1,305 proteins was quantified using SOMAscan aptamer proteomics, and associations of the differentially elevated or reduced proteins with the clinical subsets of Raynaud's Phenomenon were assessed.

RESULTS

Twenty one differentially elevated and one differentially reduced (absolute fold change >|1.3|) proteins were identified. Principal component analysis using these 22 most differentially expressed proteins resulted in excellent separation of the two Raynaud's Phenomenon clinical subsets. Remarkably, the most differentially elevated proteins are involved in enhanced inflammatory responses, immune cell activation and cell migration, and abnormal vascular functions.

CONCLUSION

Aptamer proteomic analysis of circulating exosomes identified differentially elevated or reduced proteins between Raynaud's Phenomenon at high risk of evolving into SSc and Primary Raynaud's Phenomenon patients. Some of these proteins are involved in relevant biological pathways that may play a role in SSc pathogenesis including enhanced inflammatory responses, immune cell activation, and endothelial cell and vascular abnormalities.

The Microbiome in Systemic Sclerosis: Pathophysiology and Therapeutic Potential

Systemic sclerosis (SSc), also known as scleroderma, is an autoimmune disease with unknown etiology characterized by multi-organ fibrosis. Despite substantial investigation on SSc-related cellular and molecular mechanisms, effective therapies are still lacking. The skin, lungs, and gut are the most affected organs in SSc, which act as physical barriers and constantly communicate with colonized microbiota. Recent reports have documented a unique microbiome signature, which may be the pathogenic trigger or driver of SSc. Since gut microbiota influences the efficacy and toxicity of oral drugs, evaluating drug-microbiota interactions has become an area of interest in disease treatment. The existing evidence highlights the potential of the microbial challenge as a novel therapeutic option in SSc. In this review, we have summarized the current knowledge about molecular mechanisms of SSc and highlighted the underlying role of the microbiome in SSc pathogenesis. We have also discussed the latest therapeutic interventions using microbiomes in SSc, including drug-microbiota interactions and animal disease models. This review aims to elucidate the pathophysiological connection and therapeutic potential of the microbiome in SSc. Insights into the microbiome will significantly improve our understanding of etiopathogenesis and developing therapeutics for SSc.

Randomized controlled trial of an internet-based self-guided hand exercise program to improve hand function in people with systemic sclerosis: the Scleroderma Patient-centered Intervention Network Hand Exercise Program (SPIN-HAND) trial

BACKGROUND

Systemic sclerosis (scleroderma; SSc) is a rare autoimmune connective tissue disease. Functional impairment of hands is common. The Scleroderma Patient-centered Intervention Network (SPIN)-HAND trial compared effects of offering access to an online self-guided hand exercise program to usual care on hand function (primary) and functional health outcomes (secondary) in people with SSc with at least mild hand function limitations.

METHODS

The pragmatic, two-arm, parallel-group cohort multiple randomized controlled trial was embedded in the SPIN Cohort. Cohort participants with Cochin Hand Function Scale (CHFS) scores ≥ 3 and who indicated interest in using the SPIN-HAND Program were randomized (3:2 ratio) to an offer of program access or to usual care (targeted N = 586). The SPIN-HAND program consists of 4 modules that address (1) thumb flexibility and strength; (2) finger bending; (3) finger extension; and (4) wrist flexibility and strength. The primary outcome analysis compared CHFS scores 3 months post-randomization between participants offered versus not offered the program. Secondary outcomes were CHFS scores 6 months post-randomization and functional health outcomes (Patient-Reported Outcomes Measurement Information System profile version 2.0 domain scores) 3 and 6 months post-randomization.

RESULTS

In total, 466 participants were randomized to intervention offer (N = 280) or usual care (N = 186). Of 280 participants offered the intervention, 170 (61%) consented to access the program. Of these, 117 (69%) viewed at least one hand exercise instruction video and 77 (45%) logged into the program website at least 3 times. In intent-to-treat analyses, CHFS scores were 1.2 points lower (95% CI - 2.8 to 0.3) for intervention compared to usual care 3 months post-randomization and 0.1 points lower (95% CI - 1.8 to 1.6 points) 6 months post-randomization. There were no statistically significant differences in other outcomes.

CONCLUSION

The offer to use the SPIN-HAND Program did not improve hand function. Low offer uptake, program access, and minimal usage among those who accessed the program limited our ability to determine if using the program would improve function. To improve engagement, the program could be tested in a group format or as a resource to support care provided by a physical or occupational therapist.

TRIAL REGISTRATION

NCT03419208 . Registered on February 1, 2018.

Novel role of long non-coding RNAs in autoimmune cutaneous disease

Systemic autoimmune rheumatic diseases (SARDs) are a heterogeneous group of chronic multisystem inflammatory disorders that are thought to have a complex pathophysiology, which is not yet fully understood. Recently, the role of non-coding RNAs, including long non-coding RNA (lncRNA), has been of particular interest in the pathogenesis of SARDs. We aimed to summarize the potential roles of lncRNA in SARDs affecting the skin including, systemic sclerosis (SSc), dermatomyositis (DM) and cutaneous lupus erythematosus (CLE). We conducted a narrative review summarizing original articles published until July 19, 2021, regarding lncRNA associated with SSc, DM, and CLE. Several lncRNAs were hypothesized to play an important role in disease pathogenesis of SSc, DM and CLE. In SSc, Negative Regulator of IFN Response (NRIR) was thought to modulate Interferon (IFN) response in monocytes, anti-sense gene to X-inactivation specific transcript (TSIX) to regulate increased collagen stability, HOX transcript antisense RNA (HOTAIR) to increase numbers of myofibroblasts, OTUD6B-Anti-Sense RNA 1 to decrease fibroblast apoptosis, ncRNA00201 to regulate pathways in SSc pathogenesis and carcinogenesis, H19X potentiating TGF-β-driven extracellular matrix production, and finally PSMB8-AS1 potentiates IFN response. In DM, linc-DGCR6-1 expression was hypothesized to target the USP18 protein, a type 1 IFN-inducible protein that is considered a key regulator of IFN signaling. Additionally, AL136018.1 is suggested to regulate the expression Cathepsin G, which increases the permeability of vascular endothelial cells and the chemotaxis of inflammatory cells in peripheral blood and muscle tissue in DM. Lastly, lnc-MIPOL1-6 and lnc-DDX47-3 in discoid CLE were thought to be associated with the expression of chemokines, which are significant in Th1 mediated disease. In this review, we summarize the key lncRNAs that may drive pathogenesis of these connective tissue diseases and could potentially serve as therapeutic targets in the future.

Phenotype of limited cutaneous systemic sclerosis patients with positive anti-topoisomerase I antibodies: data from the EUSTAR cohort

OBJECTIVES

To characterize patients with positive anti-topoisomerase I (ATA) in lcSSc.

METHODS

SSc patients enrolled in the EUSTAR cohort with a disease duration of ≤3 years at database entry were considered. We assessed the risk of major organ involvement in the following groups: ATA-lcSSc vs ACA-lcSSc and vs ANA without specificity (ANA)-lcSSc, and ATA-lcSSc vs ATA-dcSSc. Cox regression models with time-dependent covariates were performed with the following outcomes: new-onset interstitial lung disease (ILD), ILD progression [forced vital capacity (FVC) decline ≥10% and ≥5% vs values at ILD diagnosis), primary myocardial involvement (PMI), pulmonary hypertension (PH), any organ involvement and all-cause mortality.

RESULTS

We included 1252 patients [194 ATA-lcSSc (15.5%)], with 7.7 years (s.d. 3.5) of follow-up. ILD risk was higher in ATA-lcSSc vs ACA- and ANA-lcSSc and similar to ATA-dcSSc, although with less frequent restrictive lung disease. The risk of FVC decline ≥10% (35% of ATA-lcSSc) was lower in ATA-lcSSc than in ATA-dcSSc, whereas FVC decline ≥5% occurs similarly between ATA-lcSSc (58% of patients) and other SSc subsets, including ATA-dcSSc. The risk of PMI was similar in ATA-lcSSc and ANA-lcSSc but lower than in ACA-lcSSc; no difference in PH and mortality risk was observed among lcSSc subsets. The risk of any organ involvement, PMI and PH was lower and the mortality tended to be lower in ATA-lcSSc vs ATA-dcSSc.

CONCLUSION

ATA-lcSSc patients have a high risk of ILD, albeit with a lower risk of progression compared with ATA-dcSSc, supporting careful screening for ILD in this subgroup.

Spontaneous tendon rupture in a patient with systemic sclerosis: a case report

BACKGROUND

Systemic sclerosis (SSc) is an incurable autoimmune disease characterized by progressive skin fibrosis and organ failure. Tenosynovitis is a common musculoskeletal manifestation, but tendon rupture has seldom reported in SSc.

CASE PRESENTATION

We present a rare case of a 49-year-old female with SSc who has suffered from bilateral tendon rupture of the fourth and fifth digits with positive antinuclear antibody (ANA) and anti-centromere B antibody, but negative rheumatoid factor in serum. In the extensor tendons of the patient's hands, inflammation, edema, hypertrophy and tendon interruption were detected with ultrasound and magnetic resonance imaging(MRI). Tendon transfer repair surgery was performed and 10 mg/week methotrexate was then used in this patient. Her hand function was improved well with methotrexate and rehabilitation treatment postoperatively.

CONCLUSIONS

Early detection of tenosynovitis is necessary to prevent tendon rupture in SSc patients. Ultrasound and Magnetic Resonance Imaging appear to be useful examinations for evaluating tendon pathology for early detection.

Small airways dysfunction in patients with systemic sclerosis and interstitial lung disease

BACKGROUND

A number of studies report small airways involvement in patients with systemic sclerosis (SSc). Furthermore, small airways dysfunction is increasingly recognized in patients with interstitial lung disease (ILD) of idiopathic or autoimmune etiology. The objectives of this study were to evaluate small airways function in SSc patients with ILD and explore the effect of treatment on small airways function by using conventional and contemporary pulmonary function tests (PFTs).

METHODS

This single-center, prospective, observational study included a total of 35 SSc patients, with and without ILD based on HRCT scan, evaluated by a special radiologist blindly. Clinical data were collected from all patients who were also assessed for HRCT findings of small airways disease. Small airways function was assessed by classic spirometry, measurement of diffusing capacity for carbon monoxide, body plethysmography, single breath nitrogen washout (N2SBW) and impulse oscillometry (IOS). The prevalence of small airways dysfunction according to R5-R20, phase III slopeN2SBW and CV/VC methodologies was calculated in the total SSc population. Pulmonary function tests were compared between: (a) SSc-ILD and non-ILD patients and (b) two time points (baseline and follow up visit) in a subset of SSc-ILD patients who received treatment for ILD and were re-evaluated at a follow up visit after 12 months.

RESULTS

Phase III slopeN2SBW and R5-R20 showed the highest diagnostic performance for detecting small airways dysfunction among SSc patients (61 and 37.5%, respectively). Twenty three SSc patients were found with ILD and 14 of them had a 12-month follow up visit. SSc-ILD patients compared to those without ILD exhibited increased phase III slopeN2SBW ≥120% (p = 0.04), R5-R20 ≥0.07 kPa/L/s (p = 0.025), airway resistance (Raw) (p = 0.011), and special airway resistance (sRaw) (p = 0.02), and decreased specific airway conductance (sGaw) (p = 0.022), suggesting impaired small airways function in the SSc-ILD group. Radiographic features of SAD on HRCT were observed in 22% of SSc-ILD patients and in none of SSc-non-ILD patients. Comparison of PFTs between baseline and follow-up visit after 12 months in the 14 SSc-ILD treated patients, showed improvement of phase III slopeN2SBW (p = 0.034), R5-R20 (p = 0.035) and Raw (p = 0.044) but not sRaw and sGaw parameters.

CONCLUSION

Phase III slopeN2SBW and R5-R20 may reveal small airways dysfunction in SSc associated ILD before structural damage and may be partially improved in a subset of patients receiving treatment for ILD.

Gastrointestinal involvement in systemic sclerosis: An updated review

The gastrointestinal tract (GI) is the second most affected organ system in individuals suffering from systemic/localized scleroderma (SSc) or localized scleroderma. SSc can affect any part of the GI, between the oral cavity and anorectum. The annual incidence of SSc in the United States is estimated to be 19.3 cases per million adults, with the highest incidence reported in people aged 44 to 55. Females are 5 times more likely than males to suffer from SSc. Morbidity and mortality rates associated with SSc are predominantly elevated among patients with GI manifestations. Esophageal and intestinal manifestations impact 90% and 40% to 70% of patients with systemic scleroderma, respectively. SSc patients are known to suffer from small bowel hypomotility and small intestinal bacterial overgrowth, which cause malabsorption and malnutrition, ultimately contributing to the 50% mortality rate. Fecal incontinence is a common symptom of SSc that can lead to depression. SSc patients may suffer from gastrointestinal complications that can negatively impact their quality of life on a daily basis. Multidisciplinary approaches are necessary for systematically managing gastrointestinal complications associated with SSc. A prospective study should focus on developing targeted therapies to improve recovery patterns and prognosis in cases of SSc. This article summarizes the epidemiology, commonly reported clinical manifestations, complications, and available treatments for treating GI pathology in SSc patients.

Periostin overexpression in scleroderma cardiac tissue and its utility as a marker for disease complications

OBJECTIVE

To evaluate the levels of periostin in patients with systemic sclerosis (SSc) and their association with features of systemic sclerosis.

METHODS

The levels of periostin were assessed in the serum of 106 SSc patients and 22 healthy controls and by immunofluorescence staining in cardiac tissue from 4 SSc patients and 4 controls. Serum periostin was measured via enzyme-linked immunosorbent assay. The results were analyzed using Mann-Whitney test or Kruskal-Wallis test followed by Dunn's multiple comparisons tests and Spearman's test for correlations. Cardiac tissue from SSc patients and controls was stained for periostin and co-stained for periostin and collagen type I using immunofluorescence.

RESULTS

Periostin levels were higher in patients with SSc compared to controls and directly correlated to modified Rodnan skin score and echocardiography parameters of left ventricular measurements. Immunofluorescence staining in SSc cardiac tissue showed patchy periostin expression in all SSc patients, but not in controls. Furthermore, there was extensive periostin expression even in areas without collagen deposition, while all established fibrotic areas showed colocalization of collagen and periostin. There was no association between periostin levels and interstitial lung disease, pulmonary hypertension or other vascular complications.

CONCLUSION

Periostin is elevated in SSc cardiac tissue in vivo and circulating levels of periostin are increased in SSc, correlating with the extent of disease duration, degree of skin fibrosis, and left ventricular structural assessments. Periostin may be a potential biomarker that can provide further pathogenic insight into cardiac fibrosis in SSc.

SARA suppresses myofibroblast precursor transdifferentiation in fibrogenesis in a mouse model of scleroderma

We previously reported that Smad anchor for receptor activation (SARA) plays a critical role in maintaining epithelial cell phenotype. Here, we show that SARA suppressed myofibroblast precursor transdifferentiation in a mouse model of scleroderma. Mice overexpressing SARA specifically in PDGFR-β+ pericytes and pan-leukocytes (SARATg) developed significantly less skin fibrosis in response to bleomycin injection compared with wild-type littermates (SARAWT). Single-cell RNA-Seq analysis of skin PDGFR-β+ cells implicated pericyte subsets assuming myofibroblast characteristics under fibrotic stimuli, and SARA overexpression blocked the transition. In addition, a cluster that expresses molecules associated with Th2 cells and macrophage activation was enriched in SARAWT mice, but not in SARATg mice, after bleomycin treatment. Th2-specific Il-31 expression was increased in skin of the bleomycin-treated SARAWT mice and patients with scleroderma (or systemic sclerosis, SSc). Receptor-ligand analyses indicated that lymphocytes mediated pericyte transdifferentiation in SARAWT mice, while with SARA overexpression the myofibroblast activity of pericytes was suppressed. Together, these data suggest a potentially novel crosstalk between myofibroblast precursors and immune cells in the pathogenesis of SSc, in which SARA plays a critical role.

Deficiency of inhibitory TLR4 homolog RP105 exacerbates fibrosis

Activation of TLR4 by its cognate damage-associated molecular patterns (DAMPs) elicits potent profibrotic effects and myofibroblast activation in systemic sclerosis (SSc), while genetic targeting of TLR4 or its DAMPs in mice accelerates fibrosis resolution. To prevent aberrant DAMP/TLR4 activity, a variety of negative regulators evolved to dampen the magnitude and duration of the signaling. These include radioprotective 105 kDa (RP105), a transmembrane TLR4 homolog that competitively inhibits DAMP recognition of TLR4, blocking TLR4 signaling in immune cells. The role of RP105 in TLR4-dependent fibrotic responses in SSc is unknown. Using unbiased transcriptome analysis of skin biopsies, we found that levels of both TLR4 and its adaptor protein MD2 were elevated in SSc skin and significantly correlated with each other. Expression of RP105 was negatively associated with myofibroblast differentiation in SSc. Importantly, RP105-TLR4 association was reduced, whereas TLR4-TLR4 showed strong association in fibroblasts from patients with SSc, as evidenced by PLA assays. Moreover, RP105 adaptor MD1 expression was significantly reduced in SSc skin biopsies and explanted SSc skin fibroblasts. Exogenous RP105-MD1 abrogated, while loss of RP105 exaggerated, fibrotic cellular responses. Importantly, ablation of RP105 in mice was associated with augmented TLR4 signaling and aggravated skin fibrosis in complementary disease models. Thus, we believe RP105-MD1 to be a novel cell-intrinsic negative regulator of TLR4-MD2-driven sustained fibroblast activation, representing a critical regulatory network governing the fibrotic process. Impaired RP105 function in SSc might contribute to persistence of progression of the disease.

Scleroderma Renal Crisis With Thrombotic Microangiopathy Treated With Eculizumab

We herein report the unusual case of a 52-year-old female with systemic scleroderma who was admitted to the emergency department (ED) with renal dysfunction and hypertension. Following a decline in hemoglobin (Hb) and platelet (Plt) count, the diagnosis of scleroderma renal crisis (SRC) with associated microangiopathic hemolytic anemia was made. Renal replacement therapy using hemodialysis was required. Systemic scleroderma is a chronic autoimmune multisystem vasculopathy affecting several vessel beds, including distal extremities, kidneys, and lungs. Microangiopathic hemolytic anemia occurs in almost half of patients who develop scleroderma renal crisis. This association is thought to be related to the activation of the complement system via the classical pathway. Based on that, we administered a C5 blocker (eculizumab) to our patient and reported an unprecedented positive outcome.

Type 1 interferon activation in systemic sclerosis: a biomarker, a target or the culprit

PURPOSE OF REVIEW

Activation of the type 1 interferon (T1 IFN) pathway has been implicated in the pathogenesis of systemic sclerosis (SSc) by an increasing number of studies, most of which share key findings with similar studies in systemic lupus erythematosus (SLE). Here we will focus on the evidence for T1 IFN activation and dysregulation in SSc, and the rationale behind targeting the pathway going forward.

RECENT FINDINGS

An increased expression and activation of T1 IFN-regulated genes has been shown to be present in a significant proportion of SSc patients. TI IFN activation markers have been found to predict and correlate with response to immunosuppressive treatment as well as severity of organ involvement. As inhibition of the IFN-α receptor has been proven to be effective in active SLE, benefit may be seen in targeting the IFN pathway in SSc.

SUMMARY

The role played by T1 IFN and its regulatory genes in SSc is becoming increasingly evident and strikingly similar to the role observed in SLE. This observation, together with the benefit of type 1 IFN targeting in SLE, supports the notion of a potential therapeutic benefit in targeting T1 IFN in SSc.

Normal percentile reference curves for skin ultrasound thickness and stiffness at Rodnan sites

Objectives

Our primary objective was to establish preliminary normal reference curves for ultrasound–dermal thickness and skin stiffness in the 17 Rodnan skin sites, considering the effect of gender and age on these measures. As an exploratory objective, we investigated the effect of body mass index and the menopause on skin ultrasound measures.

Methods

A cross-sectional study was conducted involving 140 healthy volunteers, aged 20–79 years. Recruitment was stratified by gender and age (10-year categories). Ultrasound–dermal thickness and skin stiffness were assessed by high-frequency ultrasound and shear-wave elastography, respectively, at the 17 Rodnan skin sites. Outcomes were evaluated through a mixed linear model, univariate and multivariate regressions. Normal reference curves were derived for both ultrasound measures in each skin site. An online calculator of the percentiles of skin ultrasound measures was developed.

Results

Ultrasound–dermal thickness and stiffness measures were higher in men than women in all Rodnan skin sites (except in chest for ultrasound–dermal thickness). Age had also a significant impact in both ultrasound measures, but only in some skin sites. Gender and age percentile curves (97.5th, 95th, 75th, 50th, 25th, 5th, 2.5th) were plotted for each of the measures in each skin site.

Conclusions

Gender and age are strongly associated with skin ultrasound parameters, imposing the need for gender-specific and age-specific reference values. Normal reference percentile curves are provided as a basis for future cooperative work to strengthen its evidence basis, representativeness and refinement regarding potentially influential factors.

Effects of a support group leader education program jointly developed by health professionals and patients on peer leader self-efficacy among leaders of scleroderma support groups: a two-arm parallel partially nested randomised controlled trial

Background

More people with rare diseases likely receive disease education and emotional and practical support from peer-led support groups than any other way. Most rare-disease support groups are delivered outside of the health care system by untrained leaders. Potential benefits may not be achieved and harms, such as dissemination of inaccurate information, may occur. Our primary objective was to evaluate the effects of a rare-disease support group leader education program, which was developed collaboratively by researchers, peer support group leaders, and patient organization leaders, compared to waitlist control, on peer leader self-efficacy among scleroderma support group leaders.

Methods

The trial was a pragmatic, two-arm partially nested randomised controlled trial with 1:1 allocation into intervention or waitlist control. Eligible participants were existing or candidate peer support group leaders affiliated with a scleroderma patient organization. Leader training was delivered in groups of 5–6 participants weekly for 13 weeks in 60–90 min sessions via the GoToMeeting® videoconferencing platform. The program included 12 general leader training modules and one module specific to scleroderma. Primary outcome was leader self-efficacy, measured by the Support Group Leader Self-efficacy Scale (SGLSS) immediately post-intervention. Secondary outcomes were leader self-efficacy 3 months post-intervention; emotional distress, leader burnout, and volunteer satisfaction post-intervention and 3 months post-intervention; and program satisfaction among intervention participants post-intervention.

Results

One hundred forty-eight participants were randomised to intervention (N = 74) or waitlist (N = 74). Primary outcome data were provided by 146 (99%) participants. Mean number of sessions attended was 11.4 (standard deviation = 2.6). Mean program satisfaction score (CSQ-8) was 30.3 (standard deviation = 3.0; possible range 8–32). Compared to waitlist control, leader self-efficacy was higher post-intervention [SGLSS; 16.7 points, 95% CI 11.0–22.3; standardized mean difference (SMD) 0.84] and 3 months later (15.6 points, 95% CI 10.2–21.0; SMD 0.73); leader volunteer satisfaction was significantly higher at both assessments, emotional distress was lower post-intervention but not 3 months later, and leader burnout was not significantly different at either assessment.

Conclusions

Peer support group leader education improved leader self-efficacy substantially. The program could be easily adapted for support group leaders in other rare diseases.

Trial registration:NCT03965780; registered on May 29, 2019.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13023-022-02552-x.

Fibroblast A20 governs fibrosis susceptibility and its repression by DREAM promotes fibrosis in multiple organs

In addition to autoimmune and inflammatory diseases, variants of the TNFAIP3 gene encoding the ubiquitin-editing enzyme A20 are also associated with fibrosis in systemic sclerosis (SSc). However, it remains unclear how genetic factors contribute to SSc pathogenesis, and which cell types drive the disease due to SSc-specific genetic alterations. We therefore characterize the expression, function, and role of A20, and its negative transcriptional regulator DREAM, in patients with SSc and disease models. Levels of A20 are significantly reduced in SSc skin and lungs, while DREAM is elevated. In isolated fibroblasts, A20 mitigates ex vivo profibrotic responses. Mice haploinsufficient for A20, or harboring fibroblasts-specific A20 deletion, recapitulate major pathological features of SSc, whereas DREAM-null mice with elevated A20 expression are protected. In DREAM-null fibroblasts, TGF-β induces the expression of A20, compared to wild-type fibroblasts. An anti-fibrotic small molecule targeting cellular adiponectin receptors stimulates A20 expression in vitro in wild-type but not A20-deficient fibroblasts and in bleomycin-treated mice. Thus, A20 has a novel cell-intrinsic function in restraining fibroblast activation, and together with DREAM, constitutes a critical regulatory network governing the fibrotic process in SSc. A20 and DREAM represent novel druggable targets for fibrosis therapy.

Exploring metabolism in scleroderma reveals opportunities for pharmacological intervention for therapy in fibrosis

Background

Recent evidence has indicated that alterations in energy metabolism play a critical role in the pathogenesis of fibrotic diseases. Studies have suggested that ‘metabolic reprogramming’ involving the glycolysis and oxidative phosphorylation (OXPHOS) in cells lead to an enhanced generation of energy and biosynthesis. The aim of this study was to assess the molecular basis of changes in fibrotic metabolism in systemic sclerosis (Scleroderma; SSc) and highlight the most appropriate targets for anti-fibrotic therapies.

Materials and methods

Dermal fibroblasts were isolated from five SSc patients and five healthy donors. Cells were cultured in medium with/without TGF-β1 and with/without ALK5, pan-PIM or ATM kinase inhibitors. Extracellular flux analyses were performed to evaluate glycolytic and mitochondrial respiratory function. The mitochondrial network in TMRM-stained cells was visualized by confocal laser-scanning microscopy, followed by semi-automatic analysis on the ImageJ platform. Protein expression of ECM and fibroblast components, glycolytic enzymes, subunits of the five OXPHOS complexes, and dynamin-related GTPases and receptors involved in mitochondrial fission/fusion were assessed by western blotting.

Results

Enhanced mitochondrial respiration coupled to ATP production was observed in SSc fibroblasts at the expense of spare respiratory capacity. Although no difference was found in glycolysis when comparing SSc with healthy control fibroblasts, levels of phophofructokinase-1 isoform PFKM were significantly lower in SSc fibroblasts (P<0.05). Our results suggest that the number of respirasomes is decreased in the SSc mitochondria; however, the organelles formed a hyperfused network, which is thought to increase mitochondrial ATP production through complementation. The increased mitochondrial fusion correlated with a change in expression levels of regulators of mitochondrial morphology, including decreased levels of DRP1, increased levels of MIEF2 and changes in OPA1 isoform ratios. TGF-β1 treatment strongly stimulated glycolysis and mitochondrial respiration and induced the expression of fibrotic markers. The pan-PIM kinase inhibitor had no effect, whereas both ALK5 and ATM kinase inhibition abrogated TGF-β1-mediated fibroblast activation, and upregulation of glycolysis and respiration.

Conclusions

Our data provide evidence for a novel mechanism(s) by which SSc fibroblasts exhibit altered metabolic programs and highlight changes in respiration and dysregulated mitochondrial morphology and function, which can be selectively targeted by small molecule kinase inhibitors.

Establishment of a humanized animal model of systemic sclerosis in which T helper-17 cells from patients with systemic sclerosis infiltrate and cause fibrosis in the lungs and skin

Systemic sclerosis (SSc) is a chronic autoimmune disease characterized by inflammation, microangiopathy, and progressive fibrosis in the skin and internal organs. To evaluate the pathophysiologic mechanisms and efficacies of potential therapeutics for SSc, a preclinical model recapitulating the disease phenotypes is needed. Here, we introduce a novel animal model for SSc using immunodeficient mice injected with peripheral blood mononuclear cells (PBMCs) from SSc patients. Human PBMCs acquired from SSc patients and healthy controls were transferred into NOD.Cg-Prkdc^scidIl2rg^tm1Wjl (NSG) mice with concurrent bleomycin injection. Blood, skin, and lung tissues were acquired and analyzed after PBMC engraftment. In addition, we investigated whether the humanized murine model could be used to assess the efficacy of potential therapeutics for SSc. Human PBMCs from SSc patients and healthy controls were engrafted into the blood, skin, and lung tissues of NSG mice. Histological analysis of affected tissues from mice treated with SSc PBMCs (SSc hu-mice) demonstrated substantial inflammation, fibrosis and vasculopathy with human immune cell infiltration and increased expression of IL-17, TGF-β, CCL2, CCL3, and CXCL9. The proportions of circulating and tissue-infiltrating T helper 17 (Th17) cells were elevated in SSc hu-mice. These cells showed increased expression of CXCR3 and phosphorylated STAT3. SSc hu-mice treated with rebamipide and other potential Th17-cell-modulating drugs presented significantly reduced tissue fibrosis. Mice injected with patient-derived PBMCs show promise as an animal model of SSc.

A humanized mouse model of the autoimmune disease systemic sclerosis (SSc) could improve understanding of disease progression and provide a trial platform for potential treatments. SSc results in inflammation and progressive fibrosis in the skin, heart, lungs and kidneys. Existing animal models for SSc are unable to fully mimic the mechanisms behind the disease. Mi-La Cho and Sung-Hwan Park at the Catholic University of Korea, Seoul, South Korea, and co-workers injected peripheral blood cells from patients with SSc into immune-deficent mice, generating a humanized animal model. Several weeks after, the team analysed blood and tissue samples from the mice and found significant inflammation and fibrosis in the skin and lungs, consistent with SSc. Levels of proinflammatory proteins and specific human T-helper cells were significantly elevated, providing possible insights into disease initiation and progression.

CD8+ T Cell Phenotype and Function in Childhood and Adult-Onset Connective Tissue Disease

CD8+ T cells are cytotoxic lymphocytes that destroy pathogen infected and malignant cells through release of cytolytic molecules and proinflammatory cytokines. Although the role of CD8+ T cells in connective tissue diseases (CTDs) has not been explored as thoroughly as that of other immune cells, research focusing on this key component of the immune system has recently gained momentum. Aberrations in cytotoxic cell function may have implications in triggering autoimmunity and may promote tissue damage leading to exacerbation of disease. In this comprehensive review of current literature, we examine the role of CD8+ T cells in systemic lupus erythematosus, Sjögren's syndrome, systemic sclerosis, polymyositis, and dermatomyositis with specific focus on comparing what is known about CD8+ T cell peripheral blood phenotypes, CD8+ T cell function, and CD8+ T cell organ-specific profiles in adult and juvenile forms of these disorders. Although, the precise role of CD8+ T cells in the initiation of autoimmunity and disease progression remains to be elucidated, increasing evidence indicates that CD8+ T cells are emerging as an attractive target for therapy in CTDs.

SIGLEC-1 in Systemic Sclerosis: A Useful Biomarker for Differential Diagnosis

Systemic Sclerosis (SSc) is a clinically heterogeneous disease that includes an upregulation of type I interferons (IFNs). The aim of this observational study was to investigate the IFN-regulated protein Sialic Acid−Binding Ig-like Lectin 1 (SIGLEC-1) as a biomarker for disease phenotype, therapeutic response, and differential diagnosis in SSc. Levels of SIGLEC-1 expression on monocytes of 203 SSc patients were determined in a cross-sectional and longitudinal analysis using multicolor flow cytometry, then compared to 119 patients with other rheumatic diseases and 13 healthy controls. SSc patients higher SIGLEC-1 expression on monocytes (2097.94 ± 2134.39) than HCs (1167.45 ± 380.93; p = 0.49), but significantly lower levels than SLE (8761.66 ± 8325.74; p < 0.001) and MCTD (6414.50 ± 1846.55; p < 0.001) patients. A positive SIGELC-1 signature was associated with reduced forced expiratory volume (p = 0.007); however, we were unable to find an association with fibrotic or vascular disease manifestations. SIGLEC-1 remained stable over time and was independent of changes in immunosuppressive therapy. However, SIGLEC-1 is suitable for differentiating SSc from other connective tissue diseases. SIGLEC-1 expression on monocytes can be useful in the differential diagnosis of connective tissue disease but not as a biomarker for SSc disease manifestations or activity.

Detection of Epstein-Barr virus in systemic sclerosis patients: A molecular and serological based study

OBJECTIVE

This study aimed to evaluate an association between Epstein-Barr virus (EBV) and systemic sclerosis (SSc).

METHODOLOGY

One hundred and fifty (138 female, 12 male) consecutive adult SSc patients fulfilling the American College of Rheumatology (ACR)/ European League Against Rheumatism (EULAR) criteria were included in this cross-sectional study. Serological analysis by line blot for class immunoglobulin G (IgG) and IgM antibodies against EBV antigen (EBV capsid antigen [VCA] gp125, VCA p19, EBNA-1, p22, EA-D) and quantification of EBV DNA in whole blood by real-time polymerase chain reaction was performed.

RESULTS

Class IgM antibodies against VCA gp125 (22.8% vs 0%, P < .0002), VCA p19 (55.7% vs 4.4%, P < .0001), EBNA1 (35.7% vs 0%, P < .0001), p22 (24.2% vs 0%, P < .0001), EA-D (14.2% vs 2.2%, P < .04), and class IgG antibodies against p22 (95.7% vs 82.2%, P < .02) and EA-D (54.2% vs 0%, P < .0001) reactivities were significantly higher in SSc patients than in controls. The past infection was significantly associated with the control group (42.8% vs 91%, P < .0001); and the viral reactivation was significantly associated with the SSc group (55.7% vs 4.4%, P < .0001). Only three (2%) out of 150 SSc patients were positive for EBV DNA, similar to the control group (2%) (P > .9).

CONCLUSION

The study shows a strong serological association of EBV (reactivation stage) with SSc patients in the absence of viral DNA in the circulation, indicating the EBV reservoir or tropism presence elsewhere.

Dendritic cells drive profibrotic inflammation and aberrant T cell polarization in systemic sclerosis

OBJECTIVES

Systemic sclerosis (SSc) is a devastating autoimmune disease characterized by fibrosis and obliterative vasculopathy affecting the skin and visceral organs. While the processes mediating excessive extracellular matrix (EM) deposition and fibroblast proliferation are clear, the exact link between autoimmunity and fibrosis remains elusive. Th17 cells have been proposed as critical drivers of profibrotic inflammation during SSc, but little is known about the immune components supporting their pathogenic role.

METHODS

Dendritic cells (DCs) activate and shape T cell differentiation by producing polarizing cytokines. Hence, we investigated the cytokine responses of monocyte-derived DCs (Mo-DCs) from patients with limited cutaneous SSc (lcSSc), diffuse cutaneous SSc (dcSSc), and healthy controls (HC) after stimulation with toll-like receptor (TLR) agonists. Also, using co-culture assays, we analyzed T cell subpopulations after contact with autologous TLR-activated Mo-DCs.

RESULTS

In general, we observed an increased production of Th17 related cytokines like IL-1β, IL-17F, IL-21, IL-22 by SSc compared with HC Mo-DCs, with variations between lcSSc vs. dcSSc and early- vs. late-stage subgroups. Noticeably, we found a significant increment in IL-33 production by Mo-DCs in all SSc cases regardless of their clinical phenotype. Strikingly, T cells displayed Th2, Th17, and dual Th2/Th17 phenotypes after exposure to autologous TLR-stimulated Mo-DCs from SSc patients but not HC. These changes were pronounced in individuals with early-stage dcSSc and less significant in the late-stage lcSSc subgroup.

CONCLUSIONS

Our findings suggest that functional alterations of DCs subsidize the immune mechanisms favoring the aberrant T cell polarization and profibrotic inflammation behind the clinical SSc heterogeneity.

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

Background

Activation 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).

Methods

The 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.

Results

Prophylactic 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.

Conclusions

MT-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.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13075-022-02899-3.

The role of PET/CT in connective tissue disorders: systemic sclerosis, Sjögren's syndrome and systemic lupus erythematosus

Advanced imaging techniques are needed to help clinicians in the diagnosis, in the choice of the right time for therapeutic interventions or for modifications and monitoring of treatment response in patients with autoimmune connective tissue diseases. Nuclear medicine imaging, especially PET/CT and PET/MRI, may play an important role in detecting disease activity, assessing early treatment response as well as in clarifying the complex mechanisms underlying systemic sclerosis, Sjögren's syndrome or systemic lupus erythematosus. In addition, [¹⁸F]FDG PET/CT may help in excluding or detecting coexisting malignancies. Other more specific radiopharmaceuticals are being developed and investigated, targeting specific cells and molecules involved in connective tissue diseases. Further larger studies with standardized imaging protocol and image interpretation are strongly required before including PET/CT in the diagnostic work-up of subsets of patients with autoimmune connective tissue diseases.

Both T and B cells are indispensable for the development of a PBMC transfer-induced humanized mouse model for SSc

BACKGROUND

Recently, a novel humanized mouse model for systemic sclerosis (SSc) was established by transferring peripheral blood mononuclear cells (PBMC) from patients with SSc to Rag2^-/-Il2rg^-/- immunodeficient mice. Here, we aimed to investigate the role of T and B cells in this humanized mouse model.

METHODS

T and B cells were depleted in vitro from freshly isolated PBMC using anti-CD3 and anti-CD19 magnetic microbeads, respectively. Subsequently, PBMC and T or B cell-depleted PBMC were transferred into Rag2^-/-/Il2rg^-/- mice via intraperitoneal injection. Twelve weeks after the transfer, mice were sacrificed and evaluated.

RESULTS

Mice transferred with whole PBMC from SSc patients developed systemic inflammation in the lungs, kidneys, and liver, and 6 out of 11 mice died or had to be sacrificed during the experiment. By contrast, such inflammation and death were not observed in mice transferred with corresponding T or B cell-depleted PBMC. In line with this finding, transfer with whole PBMC restored the splenic white pulp composing of human T, B, and plasma cells and led to the production of a considerable amount of human autoantibodies in recipient mice, while those immunological features were rarely observed in mice that received T or B cell-depleted PBMC. In contrast to our previous findings demonstrating a transfer of the protective effect of a B cell therapy into the mouse, treatment of SSc patients with chemical immunosuppressive drugs did not affect the pathogenicity of PBMC.

CONCLUSIONS

This study demonstrates that both T and B cells are indispensable for the pathogenesis of the PBMC transfer-induced mouse model for SSc.

Role of NLRP3 inflammasome in systemic sclerosis

Systemic sclerosis (SSc) is an autoimmune rheumatic disease with high mortality, which is featured by inflammation, vascular damage, and aggressive fibrosis. To date, the pathogenesis of SSc remains unclear and effective treatments are still under research. Active NLRP3 recruits downstream proteins such as ASC and caspase-1 and assembles into inflammasome, resulting in excretion of inflammatory cytokines including IL-1β and IL-18, as well as in pyroptosis mediated by gasdermin D. Various studies demonstrated that NLRP3 inflammasome might be involved in the mechanism of tenosynovitis, arthritis, fibrosis, and vascular damage. The pathophysiological changes might be due to the activation of proinflammatory Th2 cells, profibrotic M2 macrophages, B cells, fibroblasts, and endothelial cells. Here, we review the studies focused on NLRP3 inflammasome activation, its association with innate and adaptive immune cells, endothelium injury, and differentiation of fibroblasts in SSc. Furthermore, we summarize the prospect of therapy targeting NLRP3 pathway.

New Era in Systemic Sclerosis Treatment: Recently Approved Therapeutics

Systemic sclerosis (SSc) is a chronic autoimmune disease with a poor prognosis. Among the various complications of SSc, treatment options for the fibrotic lesions, skin sclerosis, and SSc-associated interstitial lung disease (SSc-ILD) have been limited. However, since 2019, the efficacy and safety of nintedanib, tocilizumab, and rituximab for SSc or SSc-ILD have been demonstrated in double-blind, randomized, placebo-controlled trials, respectively. The antifibrotic agent nintedanib was approved for SSc-ILD in all regions of the United States, Europe, and Japan after the SENSCIS study confirmed that it suppressed the reduction in forced vital capacity (FVC), a measure of SSc-ILD. Tocilizumab, an anti-interleukin-6 receptor antibody, was approved for the treatment of SSc-ILD in the United States after the FocuSSced study showed that it inhibited the decrease in FVC. Rituximab, an anti-CD20 antibody, showed improvement in both modified Rodnan skin score, a measure of skin sclerosis, and FVC in the DESIRES study, and was approved in Japan for the treatment of SSc itself. With the development of these three drugs, SSc treatment is entering a new era. This paper outlines the latest advances in SSc therapeutics, focusing on nintedanib, tocilizumab, and rituximab.

Randomized feasibility trial of the Scleroderma Patient-centered Intervention Network hand exercise program (SPIN-HAND)

Purpose

The Scleroderma Patient-centered Intervention Network (SPIN) online hand exercise program (SPIN-HAND), is an online self-help program of hand exercises designed to improve hand function for people with scleroderma. The objective of this feasibility trial was to evaluate aspects of feasibility for conducting a full-scale randomized controlled trial of the SPIN-HAND program.

Materials and Methods

The feasibility trial was embedded in the SPIN cohort and utilized the cohort multiple randomized controlled trial (cmRCT) design. In the cmRCT design, at the time of cohort enrollment, cohort participants consent to be assessed for trial eligibility and randomized prior to being informed about trials conducted using the cohort. When trials were conducted in the cohort, participants randomized to the intervention were informed and consented to access the intervention. Participants randomized to control were not informed that they have not received an intervention. All participants eligible and randomized to participate in the trial were included in analyses on an intent-to-treat basis. Cohort participants with a Cochin Hand Function Scale score ≥ 3/90 and an interest in using an online hand-exercise intervention were randomized (1:1 ratio) to be offered as usual care plus the SPIN-HAND Program or usual care for 3 months. User satisfaction was assessed with semi-structured interviews.

Results

Of the 40 randomized participants, 24 were allocated to SPIN-HAND and 16 to usual care. Of 24 participants randomized to be offered SPIN-HAND, 15 (63%) consented to use the program. Usage of SPIN-HAND content among the 15 participants who consented to use the program was low; only five (33%) logged in more than twice. Participants found the content relevant and easy to understand (satisfaction rating 8.5/10, N = 6). Automated eligibility and randomization procedures via the SPIN Cohort platform functioned properly. The required technical support was minimal.

Conclusions

Trial methodology functioned as designed, and the SPIN-HAND Program was feasibly delivered; however, the acceptance of the offer and use of program content among accepters were low. Adjustments to information provided to potential participants will be implemented in the full-scale SPIN-HAND trial to attempt to increase offer acceptance.

Standardized incidence ratios and risk factors for cancer in patients with systemic sclerosis: Data from the Spanish Scleroderma Registry (RESCLE)

AIM

Patients with systemic sclerosis (SSc) are at increased risk of cancer, a growing cause of non-SSc-related death among these patients. We analyzed the increased cancer risk among Spanish patients with SSc using standardized incidence ratios (SIRs) and identified independent cancer risk factors in this population.

MATERIAL AND METHODS

Spanish Scleroderma Registry data were analyzed to determine the demographic characteristics of patients with SSc, and logistic regression was used to identify cancer risk factors. SIRs with 95% confidence intervals (CIs) relative to the general Spanish population were calculated.

RESULTS

Of 1930 patients with SSc, 206 had cancer, most commonly breast, lung, hematological, and colorectal cancers. Patients with SSc had increased risks of overall cancer (SIR 1.48, 95% CI 1.36-1.60; P < 0.001), and of lung (SIR 2.22, 95% CI 1.77-2.73; P < 0.001), breast (SIR 1.31, 95% CI 1.10-1.54; P = 0.003), and hematological (SIR 2.03, 95% CI 1.52-2.62; P < 0.001) cancers. Cancer was associated with older age at SSc onset (odds ratio [OR] 1.22, 95% CI 1.01-1.03; P < 0.001), the presence of primary biliary cholangitis (OR 2.35, 95% CI 1.18-4.68; P = 0.015) and forced vital capacity <70% (OR 1.8, 95% CI 1.24-2.70; P = 0.002). The presence of anticentromere antibodies lowered the risk of cancer (OR 0.66, 95% CI 0.45-0.97; P = 0.036).

CONCLUSIONS

Spanish patients with SSc had an increased cancer risk compared with the general population. Some characteristics, including specific autoantibodies, may be related to this increased risk.

Fibrotic Scar in CNS Injuries: From the Cellular Origins of Fibroblasts to the Molecular Processes of Fibrotic Scar Formation

Central nervous system (CNS) trauma activates a persistent repair response that leads to fibrotic scar formation within the lesion. This scarring is similar to other organ fibrosis in many ways; however, the unique features of the CNS differentiate it from other organs. In this review, we discuss fibrotic scar formation in CNS trauma, including the cellular origins of fibroblasts, the mechanism of fibrotic scar formation following an injury, as well as the implication of the fibrotic scar in CNS tissue remodeling and regeneration. While discussing the shared features of CNS fibrotic scar and fibrosis outside the CNS, we highlight their differences and discuss therapeutic targets that may enhance regeneration in the CNS.

Safety and efficacy of rituximab in systemic sclerosis (DESIRES): open-label extension of a double-blind, investigators-initiated, randomised, placebo-controlled trial

BACKGROUND

Results from the double-blind phase 2 DESIRES trial showed that rituximab improves skin thickening in systemic sclerosis. Here, we present the findings of a subsequent 24-week open-label extension phase.

METHODS

Patients with systemic sclerosis aged 20-79 years, who fulfilled the 2013 American College of Rheumatology and European League Against Rheumatism classification criteria, with a baseline modified Rodnan Skin Score (mRSS) of 10 or greater were enrolled into the DESIRES trial, which was an investigator-initiated, phase 2, double-blind, randomised controlled trial of rituximab versus placebo conducted at four sites in Japan. After completion of 24 weeks of treatment with either rituximab or placebo, patients in both groups received a further 24 weeks of rituximab (375 mg/m2 intravenously, once per week for 4 consecutive weeks) in an open-label extension. The primary endpoint of the double-blind trial was mRSS at week 24, which was reassessed at week 48 in the open-label extension. All endpoints were exploratory. Safety analyses included all participants who received at least one dose of study drug; efficacy analyses included those who had received at least one dose and undergone efficacy assessment at 24 weeks in the double-blind phase and at 48 weeks in the extension phase. The DESIRES study is registered with ClinicalTrials.gov, NCT04274257, and UMIN-CTR, UMIN000030139.

FINDINGS

Between Nov 28, 2017, and Nov 6, 2018, 56 patients were randomly assigned to either rituximab (n=28) or placebo (n=28) in a double-blind study. 26 patients initially assigned to rituximab and 20 assigned to placebo transitioned to the open-label extension and all received at least one dose of rituximab; 24 participants in the rituximab-rituximab group and 19 in the placebo-rituximab group completed the extension phase. In the rituximab-rituximab group, there was an improvement in mRSS from baseline at week 24 (-5·81 [SD 3·16]), with further improvement at week 48 (-8·88 [3·10]). In the placebo-rituximab group, mRSS worsened at week 24 (2·14 [SD 5·51]) but improved at the week 48 assessment (-6·05 [4·43]). One patient each in the rituximab-rituximab and placebo-rituximab groups experienced one serious adverse event during the open-label phase (cholangitis and pneumococcal pneumonia, respectively). There were no deaths during follow-up.

INTERPRETATION

Two courses of rituximab is a safe treatment that can provide sustained improvement in systemic sclerosis for at least 48 weeks.

FUNDING

Japan Agency for Medical Research and Development.

TRANSLATION

For the Japanese translation of the abstract see Supplementary Materials section.

Kidney transplantation in systemic sclerosis: Advances in graft, disease, and patient outcome

Systemic sclerosis (SSc) is an immune-mediated rheumatic disease characterized by vascular abnormalities, tissue fibrosis, and inflammation. Renal disease occurring in patients with SSc may have a variable clinicopathological picture. However, the most specific renal condition associated with this disease is the scleroderma renal crisis (SRC), characterized by acute onset of renal failure and severe hypertension. SRC develops in about 20% of cases of SSc, especially in those patients with diffuse cutaneous disease. The prognosis of this condition is often negative, with a rapid progression to end-stage renal disease (ESRD). The advent of the antihypertensive angiotensin-converting enzyme inhibitors in 1980 was associated with a significant improvement in patients’ survival and recovery of renal function. However, the prognosis of these patients can still be improved. The dialytic condition is associated with early death, and mortality is significantly higher than among patients undergoing renal replacement therapy (RRT) due to other conditions. Patients with SRC who show no signs of renal functional recovery despite timely blood pressure control are candidates for kidney transplantation (KT). In this review, we reported the most recent advances in KT in patients with ESRD due to SSc, with a particular overview of the risk of disease recurrence after transplantation and the evolution of other disease manifestations.

Psychological Fragility in an Italian Cohort of Systemic Sclerosis Patients During COVID-19 Pandemic Category: Short Communication

Objective

This work aims to evaluate the prevalence of anxiety and COVID-19-related fear in systemic sclerosis (SSc) patients during the second and third waves of the SARS-CoV-2 pandemic in Italy and their possible associated factors.

Methods

A cohort study was carried out on 114 SSc patients referred to our Scleroderma Clinic, matched for sex and age. Twenty-eight of them had missed scheduled examinations during the October 2020-March 2021 period and 86 has attended regular outpatient visits during the same period. Both groups were administered (by telephone for cases and in-person for controls) the Generalized Anxiety Disorder Scale-7 (GAD-7) questionnaire and the validated on SSc patients COVID-19 Fears Questionnaire for Chronic Medical Conditions (COVID-19 Fears). Concurrent factors related to higher scores were investigated in patients who did not have an outpatient follow-up.

Results

The missing group had significantly more patients scoring ≥8 on the GAD-7 questionnaire [22 (78.6%) vs 16 (18.6%), p < 0.0001] and significantly higher scores on the COVID-19 Fears questionnaire (median [quartiles] 31.5 [26.25;37.25] vs 20 [13.75;28], p < 0.0001) than the attending group. Multivariate analysis performed on the missing patients group showed a significant association of the lack of work and ongoing therapy for anxiety/depression with GAD-7 (p = 0.0275 and p = 0.0188) and COVID-19 Fears score (p = 0.0016 and p = 0.0099).

Conclusion

Anxiety disorder and COVID-19-related fear were greater in SSc patients who missed regular follow-ups and are associated with a lack of work activity. These findings aim to identify a subgroup deserving attention regarding risk factors for missed periodic controls.

Effect of Nintedanib on Progression of Systemic Sclerosis-Associated Interstitial Lung Disease Over 100 Weeks: Data From a Randomized Controlled Trial

Objective

In the SENSCIS trial, participants with systemic sclerosis‐associated interstitial lung disease (SSc‐ILD) were randomized to receive nintedanib or placebo until the last participant reached week 52 but for 100 weeks or less. Nintedanib reduced the rate of decline in forced vital capacity (FVC) (ml/year) over 52 weeks by 44% (41 ml [95% confidence interval (95% CI): 2.9‐79.0]) versus placebo. We investigated the effect of nintedanib over the whole SENSCIS trial.

Methods

The annual rate of decline in FVC (ml/year) over the whole trial was assessed descriptively using 1) on‐treatment data plus off‐treatment data from participants who prematurely discontinued treatment (intent‐to‐treat analysis) and 2) only on‐treatment data to assess the effect of nintedanib in participants who remained on treatment.

Results

In the intent‐to‐treat analysis, the adjusted mean (SE) annual rate of decline in FVC over 100 weeks was −54.9 (11.1) and −88.8 (10.9) ml/year in the nintedanib (n = 287) and placebo (n = 288) groups, respectively (difference 34.0 ml/year [95% CI: 3.4‐64.5]). In the on‐treatment analysis, the adjusted mean (SE) annual rate of decline in FVC over 100 weeks was −55.1 (12.3) and −94.0 (11.7) ml/year in the nintedanib (n = 286) and placebo (n = 288) groups, respectively (difference 38.9 ml/year [95% CI: 5.6‐72.1]). The adverse event profile of nintedanib over 100 weeks was consistent with that observed over 52 weeks.

Conclusion

Nintedanib provides a sustained benefit on slowing the progression of SSc‐ILD over 100 weeks, with adverse events that are manageable for most patients.

Anti-fibrotic effect of a selective estrogen receptor modulator in systemic sclerosis

Background

The rarity of systemic sclerosis (SSc) has hampered the development of therapies for this intractable autoimmune disease. Induced pluripotent stem cell (iPSC) can be differentiated into the key disease-affected cells in vitro. The generation of patient-derived iPSCs has opened up possibilities for rare disease modeling. Since these cells can recapitulate the disease phenotypes of the cell in question, they are useful high-throughput platforms for screening for drugs that can reverse these abnormal phenotypes.

Methods

SSc iPSC was generated from PBMC by Sendai virus. Human iPSC lines from SSc patients were differentiated into dermal fibroblasts and keratinocytes. The iPSC-derived differentiated cells from the SSc patients were used on high-throughput platforms to screen for FDA-approved drugs that could be effective treatments for SSc.

Results

Skin organoids were generated from these cells exhibited fibrosis that resembled SSc skin. Screening of the 770-FDA-approved drug library showed that the anti-osteoporotic drug raloxifene reduced SSc iPSC-derived fibroblast proliferation and extracellular matrix production and skin fibrosis in organoids and bleomycin-induced SSc-model mice.

Conclusions

This study reveals that a disease model of systemic sclerosis generated using iPSCs-derived skin organoid is a novel tool for in vitro and in vivo dermatologic research. Since raloxifene and bazedoxifene are well-tolerated anti-osteoporotic drugs, our findings suggest that selective estrogen receptor modulator (SERM)-class drugs could treat SSc fibrosis.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13287-022-02987-w.

Gut microbe-derived metabolite trimethylamine N-oxide activates PERK to drive fibrogenic mesenchymal differentiation

Intestinal dysbiosis is prominent in systemic sclerosis (SSc), but it remains unknown how it contributes to microvascular injury and fibrosis that are hallmarks of this disease. Trimethylamine (TMA) is generated by the gut microbiome and in the host converted by flavin-containing monooxygenase (FMO3) into trimethylamine N-oxide (TMAO), which has been implicated in chronic cardiovascular and metabolic diseases. Using cell culture systems and patient biopsies, we now show that TMAO reprograms skin fibroblasts, vascular endothelial cells, and adipocytic progenitor cells into myofibroblasts via the putative TMAO receptor protein R-like endoplasmic reticulum kinase (PERK). Remarkably, FMO3 was detected in skin fibroblasts and its expression stimulated by TGF-β1. Moreover, FMO3 was elevated in SSc skin biopsies and in SSc fibroblasts. A meta-organismal pathway thus might in SSc link gut microbiome to vascular remodeling and fibrosis via stromal cell reprogramming, implicating the FMO3-TMAO-PERK axis in pathogenesis, and as a promising target for therapy.

The promise of precision medicine in rheumatology

Systemic autoimmune rheumatic diseases (SARDs) exhibit extensive heterogeneity in clinical presentation, disease course, and treatment response. Therefore, precision medicine - whereby treatment is tailored according to the underlying pathogenic mechanisms of an individual patient at a specific time - represents the 'holy grail' in SARD clinical care. Current strategies include treat-to-target therapies and autoantibody testing for patient stratification; however, these are far from optimal. Recent innovations in high-throughput 'omic' technologies are now enabling comprehensive profiling at multiple levels, helping to identify subgroups of patients who may taper off potentially toxic medications or better respond to current molecular targeted therapies. Such advances may help to optimize outcomes and identify new pathways for treatment, but there are many challenges along the path towards clinical translation. In this Review, we discuss recent efforts to dissect cellular and molecular heterogeneity across multiple SARDs and future directions for implementing stratification approaches for SARD treatment in the clinic.

Profibrotic Role of Inducible Heat Shock Protein 90α Isoform in Systemic Sclerosis

Systemic sclerosis (SSc) is an autoimmune disease that affects skin and multiple internal organs. TGF-β, a central trigger of cutaneous fibrosis, activates fibroblasts with the involvement of the stress-inducible chaperone heat shock protein 90 isoform α (Hsp90α). Available evidence supports overexpression and secretion of Hsp90α as a feature in profibrotic pathological conditions. The aim of this work is to investigate the expression and function of Hsp90α in experimental models of skin fibrosis such as human fibroblasts, C57BL/6 mice, and in human SSc. For this purpose, we generated a new experimental model based on doxorubicin administration with improved characteristics with respect to the bleomycin model. We visualized disease progression in vivo by fluorescence imaging. In this work, we obtained Hsp90α mRNA overexpression in human skin fibroblasts, in bleomycin- and doxorubicin-induced mouse fibrotic skin, and in lungs of bleomycin- and doxorubicin-treated mice. Hsp90α-deficient mice showed significantly decreased skin thickness compared with wild-type mice in both animal models. In SSc patients, serum Hsp90α levels were increased in patients with lung involvement and in patients with the diffuse form of SSc (dSSc) compared with patients with the limited form of SSc. The serum Hsp90α levels of patients dSSc were correlated with the Rodnan score and the forced vital capacity variable. These results provide new supportive evidence of the contribution of the Hsp90α isoform in the development of skin fibrosis. In SSc, these results indicated that higher serum levels were associated with dSSc and lung fibrosis.

Toward Molecular Stratification and Precision Medicine in Systemic Sclerosis

Systemic sclerosis (SSc), a complex multi-systemic disease characterized by immune dysregulation, vasculopathy and fibrosis, is associated with high mortality. Its pathogenesis is only partially understood. The heterogenous pathological processes that define SSc and its stages present a challenge to targeting appropriate treatment, with differing treatment outcomes of SSc patients despite similar initial clinical presentations. Timing of the appropriate treatments targeted at the underlying disease process is critical. For example, immunomodulatory treatments may be used for patients in a predominantly inflammatory phase, anti-fibrotic treatments for those in the fibrotic phase, or combination therapies for those in the fibro-inflammatory phase. In advancing personalized care through precision medicine, groups of patients with similar disease characteristics and shared pathological processes may be identified through molecular stratification. This would improve current clinical sub-setting systems and guide personalization of therapies. In this review, we will provide updates in SSc clinical and molecular stratification in relation to patient outcomes and treatment responses. Promises of molecular stratification through advances in high-dimensional tools, including omic-based stratification (transcriptomics, genomics, epigenomics, proteomics, cytomics, microbiomics) and machine learning will be discussed. Innovative and more granular stratification systems that integrate molecular characteristics to clinical phenotypes would potentially improve therapeutic approaches through personalized medicine and lead to better patient outcomes.

A Summary on the Genetics of Systemic Lupus Erythematosus, Rheumatoid Arthritis, Systemic Sclerosis, and Sjögren's Syndrome

Systemic lupus erythematosus, systemic sclerosis, rheumatoid arthritis, and Sjögren's syndrome are four major autoimmune rheumatic diseases characterized by the presence of autoantibodies, caused by a dysregulation of the immune system that leads to a wide variety of clinical manifestations. These conditions present complex etiologies strongly influenced by multiple environmental and genetic factors. The human leukocyte antigen (HLA) region was the first locus identified to be associated and still represents the strongest susceptibility factor for each of these conditions, particularly the HLA class II genes, including DQA1, DQB1, and DRB1, but class I genes have also been associated. Over the last two decades, the genetic component of these disorders has been extensively investigated and hundreds of non-HLA risk genetic variants have been uncovered. Furthermore, it is widely accepted that autoimmune rheumatic diseases share molecular disease pathways, such as the interferon (IFN) type I pathways, which are reflected in a common genetic background. Some examples of well-known pleiotropic loci for autoimmune rheumatic diseases are the HLA region, DNASEL13, TNIP1, and IRF5, among others. The identification of the causal molecular mechanisms behind the genetic associations is still a challenge. However, recent advances have been achieved through mouse models and functional studies of the loci. Here, we provide an updated overview of the genetic architecture underlying these four autoimmune rheumatic diseases, with a special focus on the HLA region.

Pure White Cell Aplasia Complicated by Systemic Sclerosis with Accompanying Scleroderma Renal Crisis

Pure white cell aplasia (PWCA) is a rare neutropenic disorder caused by absence of neutrophil-lineage cells. A 49-year-old man was diagnosed with scleroderma renal crisis 2 months prior to admission to Ohta-Nishinouchi Hospital after experiencing a fever and abdominal pain. Blood tests revealed severe neutropenia, and bone marrow aspirate showed the absence of neutrophil-lineage cells. He was diagnosed with PWCA. Steroids alone were not effective, but adding cyclosporine A and high-dose immunoglobulin recovered his neutropenia and improved his condition. Cyclosporine A and high-dose immunoglobulin are thus considered effective for treating PWCA in autoimmune diseases.

JAK1/2 Inhibitor Baricitinib Improves Skin Fibrosis and Digital Ulcers in Systemic Sclerosis

Background

Systemic sclerosis (SSc) is a rare disabling connective tissue disease with few available treatment options. Diffuse cutaneous systemic sclerosis (dcSSc) is associated with high mortality. A previous experiment has shown that JAK2 inhibitor can significantly improve skin fibrosis in bleomycin (BLM)-induced murine model, including reducing dermal thickening and collagen accumulation. We aimed to describe the efficacy of oral JAK1/2 inhibitor baricitinib in SSc patients, especially focusing on skin fibrosis and microvascular manifestations.

Methods

We described the different effects of oral selective JAK1, JAK2, or JAK3 inhibitor treatment in a BLM-induced skin fibrosis mouse model. Furthermore, 10 adult patients with dcSSc were treated with baricitinib. We assessed the changes in modified rodman skin score (mRSS) and digital ulcer net burden at week 12 and 24 from baseline. We also compared the absolute changes in scores on the Scleroderma Health Assessment Questionnaire (SHAQ) and a total score on the St. George's Respiratory Questionnaire (SGRQ) over a 24-week period.

Results

In the experimental mouse model of skin fibrosis, a JAK1 and JAK2 inhibitor ameliorated skin fibrosis, and a JAK2 inhibitor had the most obvious effect. Treatment with the JAK2 inhibitor also blunted the capillary rarefaction. We demonstrated that skin fibrosis and digital ulcers were significantly relieved in 10 SSc patients treated with baricitinib. The mRSS significantly improved at week 12 from baseline, with a mean change in mRSS of -8.3 [95% confidence interval (CI), -12.03 to -4.574; p = 0.0007] and improved greater at week 24 to -11.67 (95% CI, -16.84 to -6.496; p = 0.0008). Among the four patients with digital ulcers (DU), three were completely healed at week 24, the number of ulcers in another patient was significantly reduced, and there was no patient with new ulcers. Only one adverse event (AE) of herpes zoster was observed.

Conclusions

Our results indicate that selective JAK1 and JAK2 inhibitor alleviates skin fibrosis, and oral JAK1/2 inhibitor baricitinib is a potentially effective treatment for dcSSc patients with skin fibrosis and DU. Baricitinib was well-tolerated by most patients in this study. Additional large clinical trials are needed to confirm our pilot findings.

Chinese Clinical Trial Registry Number

ChiCTR2000030995.

The compound LG283 inhibits bleomycin-induced skin fibrosis via antagonizing TGF-β signaling

Background

Systemic sclerosis (SSc) is a collagen disease that exhibits intractable fibrosis and vascular injury of the skin and internal organs. Transforming growth factor-β (TGF-β)/Smad signaling plays a central role in extracellular matrix (ECM) production by α-SMA-positive myofibroblasts. Myofibroblasts may be partially derived from various precursor cells in addition to resident fibroblasts. Recently, our high-throughput in vitro screening discovered a small compound, LG283, that may disrupt the differentiation of epithelial cells into myofibroblasts. This compound was originally generated as a curcumin derivative.

Methods

In this study, we investigated the effect of LG283 on inhibiting fibrosis and its mechanism. The action of LG283 on TGF-β-dependent fibrogenic activity and epithelial-mesenchymal transition (EMT) was analyzed in vitro. The effects of LG283 were also examined in a bleomycin-induced skin fibrosis mouse model.

Results

LG283 suppressed TGF-β-induced expression of ECM, α-SMA, and transcription factors Snail 1 and 2, and Smad3 phosphorylation in cultured human dermal fibroblasts. LG283 was also found to block EMT induction in cultured human epithelial cells. During these processes, Smad3 phosphorylation and/or expression of Snail 1 and 2 were inhibited by LG283 treatment. In the bleomycin-induced skin fibrosis model, oral administration of LG283 efficiently protected against the development of fibrosis and decrease of capillary vessels without significantly affecting cell infiltration or cytokine concentrations in the skin. No apparent adverse effects of LG283 were found. LG283 treatment remarkably inhibited the enhanced expression of α-SMA and phosphorylated Smad3, as well as those of Snail 1 and 2, in the bleomycin-injected skin.

Conclusions

The LG283 compound exhibits antagonistic activity on fibrosis and vascular injury through inhibition of TGF-β/Smad/Snail mesenchymal transition pathways and thus, may be a candidate therapeutic for the treatment of SSc. Although the involvement of EMT in the pathogenesis of SSc remains unclear, the screening of EMT regulatory compounds may be an attractive approach for SSc therapy.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13075-022-02773-2.

Raynaud's Phenomenon with Focus on Systemic Sclerosis

Raynaud’s phenomenon is a painful vascular condition in which abnormal vasoconstriction of the digital arteries causes blanching of the skin. The treatment approach can vary depending on the underlying cause of disease. Raynaud’s phenomenon can present as a primary symptom, in which there is no evidence of underlying disease, or secondary to a range of medical conditions or therapies. Systemic sclerosis is one of the most frequent causes of secondary Raynaud’s phenomenon; its appearance may occur long before other signs and symptoms. Timely, accurate identification of secondary Raynaud’s phenomenon may accelerate a final diagnosis and positively alter prognosis. Capillaroscopy is fundamental in the diagnosis and differentiation of primary and secondary Raynaud’s phenomenon. It is helpful in the very early stages of systemic sclerosis, along with its role in disease monitoring. An extensive range of pharmacotherapies with various routes of administration are available for Raynaud’s phenomenon but a standardized therapeutic plan is still lacking. This review provides insight into recent advances in the understanding of Raynaud’s phenomenon pathophysiology, diagnostic methods, and treatment approaches.

Delivery of sorafenib by myofibroblast-targeted nanoparticles for the treatment of renal fibrosis

Fibrosis is an excessive accumulation of the extracellular matrix within solid organs in response to injury and a common pathway that leads functional failure. No clinically approved agent is available to reverse or even prevent this process. Herein, we report a nanotechnology-based approach that utilizes a drug carrier to deliver a therapeutic cargo specifically to fibrotic kidneys, thereby improving the antifibrotic effect of the drug and reducing systemic toxicity. We first adopted in vitro-in vivo combinatorial phage display technology to identify peptide ligands that target myofibroblasts in mouse unilateral ureteral obstruction (UUO)-induced fibrotic kidneys. We then engineered lipid-coated poly(lactic-co-glycolic acid) nanoparticles (NPs) with fibrotic kidney-homing peptides on the surface and sorafenib, a potent antineoplastic multikinase inhibitor, encapsulated in the core. Sorafenib loaded in the myofibroblast-targeted NPs significantly reduced the infiltration of α-smooth muscle actin-expressing myofibroblasts and deposition of collagen I in UUO-treated kidneys and enhanced renal plasma flow measured by Technetium-99m mercaptoacetyltriglycine scintigraphy. This study demonstrates the therapeutic potential of the newly identified peptide fragments as anchors to target myofibroblasts and represents a strategic advance for selective delivery of sorafenib to treat renal fibrosis. SIGNIFICANCE STATEMENT: Renal fibrosis is a pathological feature accounting for the majority of issues in chronic kidney disease (CKD), which may progress to end-stage renal disease (ESRD). This manuscript describes a myofibroblast-targeting drug delivery system modified with phage-displayed fibrotic kidney-homing peptides. By loading the myofibroblast-targeting nanoparticles (NPs) with sorafenib, a multikinase inhibitor, the NPs could suppress collagen synthesis in cultured human myofibroblasts. When given intravenously to mice with UUO-induced renal fibrosis, sorafenib loaded in myofibroblast-targeting NPs significantly ameliorated renal fibrosis. This approach provides an efficient therapeutic option to renal fibrosis. The myofibroblast-targeting peptide ligands and nanoscale drug carriers may be translated into clinical application in the future.

Study Protocol: A Randomized Controlled Prospective Single-Center Feasibility Study of Rheopheresis for Raynaud’s Syndrome and Digital Ulcers in Systemic Sclerosis (RHEACT Study)

Introduction

Raynaud’s phenomenon (RP) and digital ulcers (DU) are frequent manifestations of Systemic Sclerosis (SSc). Despite being very common in SSc patients, both conditions have proven to be notoriously difficult to study. There are very few available approved drugs with varying efficacy. It has been shown that the presence of DU is associated with increased whole blood viscosity (WBV). Rheopheresis (RheoP) is an extracorporeal apheresis technique used to treat microcirculatory disorders by improving blood viscosity. Improved blood flow and wound healing after RheoP treatments have been reported in single case reports.

Methods and Analysis

We report the clinical trial protocol of “A randomized controlled prospective single-center feasibility study of Rheopheresis for Raynaud’s syndrome and Digital Ulcers in Systemic Sclerosis (RHEACT).” RHEACT aims to investigate the efficacy of RheoP on the Raynaud Condition Score (RCS) as the primary efficacy outcome measure after 16 weeks from baseline. Thirty patients will be randomized in a 1:1:1 ratio to one of two RheoP treatment groups or assigned to the standard of care (SoC) control group (intravenous iloprost). Secondary endpoints include changes in DU, changes in nailfold video capillaroscopy and patient-reported-outcomes (Scleroderma Health Assessment Questionnaire, FACIT-Fatigue, and the Disability of Arm, Shoulder, and Hand, quick version).

Discussion

Apheresis techniques have been investigated in SSc but mainly in observational, retrospective studies, or single case reports. RheoP is a pathophysiologically driven potential new therapy for heavily burdened patients with SSc-associated secondary RP with or without DU.

Ethics and Dissemination

The study was registered at clinicaltrials.gov (Identifier: NCT05204784). Furthermore, the study is made publicly available on the website of the German network of Systemic Sclerosis “Deutsches Netzwerk Systemische Sklerodermie (DNSS).”

LGR5 expressing skin fibroblasts define a major cellular hub perturbed in scleroderma

Systemic sclerosis (scleroderma, SSc) is an incurable autoimmune disease with high morbidity and mortality rates. Here, we conducted a population-scale single-cell genomic analysis of skin and blood samples of 56 healthy controls and 97 SSc patients at different stages of the disease. We found immune compartment dysfunction only in a specific subtype of diffuse SSc patients but global dysregulation of the stromal compartment, particularly in a previously undefined subset of LGR5⁺-scleroderma-associated fibroblasts (ScAFs). ScAFs are perturbed morphologically and molecularly in SSc patients. Single-cell multiome profiling of stromal cells revealed ScAF-specific markers, pathways, regulatory elements, and transcription factors underlining disease development. Systematic analysis of these molecular features with clinical metadata associates specific ScAF targets with disease pathogenesis and SSc clinical traits. Our high-resolution atlas of the sclerodermatous skin spectrum will enable a paradigm shift in the understanding of SSc disease and facilitate the development of biomarkers and therapeutic strategies.

The Roles of Noncoding RNAs in Systemic Sclerosis

Noncoding RNAs (ncRNAs) constitute more than 90% of the RNAs in the human genome. In the past decades, studies have changed our perception of ncRNAs from “junk” transcriptional products to functional regulatory molecules that mediate critical processes, including chromosomal modifications, mRNA splicing and stability, and translation, as well as key signaling pathways. Emerging evidence suggests that ncRNAs are abnormally expressed in not only cancer but also autoimmune diseases, such as systemic sclerosis (SSc), and may serve as novel biomarkers and therapeutic targets for the diagnosis and treatment of SSc. However, the functions and underlying mechanisms of ncRNAs in SSc remain incompletely understood. In this review, we discuss the current findings on the biogenetic processes and functions of ncRNAs, including microRNAs and long noncoding RNAs, as well as explore emerging ncRNA-based diagnostics and therapies for SSc.