Search

In recent years, rapid advances in research methods have made single cell analysis possible. Systemic sclerosis (SSc), a disease characterized by the triad of immune abnormalities, fibrosis, and vasculopathy, has also been the subject of various analyses. To summarize the results of single cell analysis in SSc accumulated to date and to deepen our understanding of SSc. Four databases were used to perform a database search on 23rd June 2023. Assessed Grading of Recommendations Assessment, Development and Evaluation certainty of evidence were performed according to PRISMA guidelines. The analysis was completed on July 2023. 17 studies with 358 SSc patients were included. Three studies used PBMCs, six used skin, nine used lung with SSc-interstitial lung diseases (ILDs), and one used lung with SSc-pulmonary arterial hypertension (PAH). The cells studied included immune cells such as T cells, natural killer cells, monocytes, macrophages, and dendritic cells, as well as endothelial cells, fibroblasts, keratinocytes, alveolar type I cells, basal epithelial cells, smooth muscle cells, mesothelial cells, etc. This systematic review revealed the results of single cell analysis, suggesting that PBMCs, skin, SSc-ILD, and SSc-PAH show activation and dysfunction of cells associated with immune-abnormalities, fibrosis, and vasculopathy, respectively. [ABSTRACT FROM AUTHOR]

In recent years, the medical use of cannabinoids has attracted growing attention worldwide. In particular, anti‐inflammatory properties of cannabinoids led to their emergence as potential therapeutic options for autoimmune and inflammatory disorders. Recent studies have also shown that cannabinoid receptors are widely expressed and have endogenous ligands in the skin, suggesting that the skin has its own endocannabinoid system. The aim of this review is to discuss the potential therapeutic effects of cannabinoids in autoimmune and inflammatory skin diseases. Following an overview of cannabinoids and the endocannabinoid system, we describe the cellular and molecular mechanisms of cannabinoids in skin health and disease. We then review the clinical studies of cannabinoids in autoimmune and inflammatory skin diseases including systemic sclerosis (SSc), dermatomyositis (DM), psoriasis (Pso) and atopic dermatitis (AD). A primary literature search was conducted in July 2023, using PubMed and Web of Science. A total of 15 articles were included after excluding reviews, non‐human studies and in vitro studies from 389 non‐duplicated articles. Available evidence suggests that cannabinoids may be beneficial for SSc, DM, Pso and AD. However, further studies, ideally randomized controlled trials, are needed to further evaluate the use of cannabinoids in autoimmune and inflammatory skin diseases. [ABSTRACT FROM AUTHOR]

Objective: In prevous studies, we established a new animal model, KLF5+/−;Fli‐1+/− mice, in which fundamental pathologic features of systemic sclerosis (SSc) are broadly recapitulated. SSc vasculopathy is believed to occur as a result of impaired vascular remodeling, but its detailed mechanism of action remains unknown. To address this, the present study investigated the properties of dermal microvascular endothelial cells (DMECs), bone marrow–derived endothelial progenitor cells (BM‐EPCs), and bone marrow–derived mesenchymal stem cells (BM‐MSCs), a precursor of pericytes, in KLF5+/−;Fli‐1+/− mice. Methods: Neovascularization and angiogenesis were assessed in KLF5+/−;Fli‐1+/− mice by in vivo Matrigel plug assay and in vitro tube formation assay, respectively. The properties of mouse BM‐EPCs and BM‐MSCs were assessed with in vitro studies. Dermal vasculature was visualized in vivo by injecting the mice with fluorescein isothiocyanate–conjugated dextran. Results: Neovascularization was diminished in skin‐embedded Matrigel plugs from KLF5+/−;Fli‐1+/− mice. DMECs from KLF5+/−;Fli‐1+/− mice showed defective tubulogenic activity, decreased expression of VE‐cadherin and CD31, and an imbalance in the expression of Notch1/Dll4, suggesting that angiogenesis and anastomosis are disturbed. KLF5+/−;Fli‐1+/− mouse BM‐MSCs exhibited enhanced proliferation and migration and increased collagen production following stimulation with transforming growth factor β1, indicating that these cells differentiate preferentially into myofibroblasts rather than pericytes. KLF5+/−;Fli‐1+/− mouse BM‐EPCs displayed a transition toward mesenchymal cells, suggesting that vasculogenesis is impaired. Wound healing was delayed in KLF5+/−;Fli‐1+/− mice (mean ± SD healing time 15.67 ± 0.82 days versus 13.50 ± 0.84 days; P = 0.0017), and the vascular network was poorly developed in wound scar tissue. Conclusion: The characteristics observed in the KLF5+/−;Fli‐1+/− mouse model — specifically, impaired neovascularization and vascular maturation — are similar to those observed in human SSc, and could be at least partially attributable to the induction of SSc‐like properties in DMECs, BM‐EPCs, and BM‐MSCs. These findings indicate the critical contribution of Klf5 and Fli1 deficiency in vascular cells and related cell precursors to the development of SSc vasculopathy. [ABSTRACT FROM AUTHOR]

Objectives Adipsin, or complement factor D, is a serine proteinase catalysing complement factor C3 breakdown, leading to the production of opsonin (C3b), membrane attack complex (C5b–C9) and anaphylatoxins (C3a and C5a). Since adipsin is potentially associated with pulmonary arterial hypertension in SSc, we investigated adipsin expression in dermal small vessels of SSc-involved skin, the mechanism regulating adipsin expression in endothelial cells, and the correlation of serum adipsin levels with SSc clinical symptoms. Methods Adipsin expression was assessed by immunohistochemistry with skin sections of SSc and healthy subjects. mRNA levels of target genes and transcription factor binding to the ADIPSIN promoter were evaluated by quantitative reverse transcription PCR and chromatin immunoprecipitation, respectively. Serum adipsin levels were determined by enzyme-linked immunosorbent assay. Results Adipsin expression was remarkably increased in dermal small vessels of SSc-involved skin as compared with those of healthy control skin. Consistent with the notion that Fli1 deficiency induces SSc-like phenotypes in various types of cells, FLI1 siRNA enhanced adipsin expression at protein and mRNA levels and Fli1 bound to the ADIPSIN promoter in human dermal microvascular endothelial cells. Serum adipsin levels were significantly lower in diffuse cutaneous SSc patients than in limited cutaneous SSc patients and healthy controls, and were associated positively with elevated right ventricular systolic pressure and inversely with interstitial lung disease by multivariate regression analysis. Conclusion Adipsin is up-regulated at least partially by Fli1 deficiency in endothelial cells, potentially contributing to the development of pulmonary vascular involvement in SSc. [ABSTRACT FROM AUTHOR]

Backgrounds: Stratified epithelia have caught much attention as potential contributors to the development of dermal and oesophageal fibrosis in systemic sclerosis (SSc). Galectin‐7 is a marker of all types of stratified epithelia, which is involved in the maintenance of epidermal homeostasis. So far, the role of galectin‐7 has not been studied in SSc. Objectives: To investigate the potential contribution of galectin‐7 to the development of clinical manifestations in SSc. Methods: Galectin‐7 expression was examined in skin samples and cultured keratinocytes by immunostaining and/or quantitative reverse transcription PCR. Serum galectin‐7 levels were determined by enzyme‐linked immunosorbent assay in 63 SSc and 20 healthy subjects. Results: Galectin‐7 expression was markedly decreased in the epidermis of SSc lesional skin compared with that of healthy control skin. Serum galectin‐7 levels were significantly lower in SSc patients than in healthy controls and inversely correlated with skin score. In addition, SSc patients with diffuse pigmentation and those with oesophageal dysfunction had significantly decreased serum galectin‐7 levels as compared to those without each symptom. Importantly, endothelin‐1 stimulation suppressed galectin‐7 expression in normal human keratinocytes, and bosentan, a dual endothelin receptor antagonist, reversed circulating galectin‐7 levels and epidermal galectin‐7 expression in SSc patients. Conclusions: Galectin‐7 downregulation in stratified epithelia, which is mediated at least partially by autocrine endothelin stimulation, may contribute to the development of cutaneous manifestations and oesophageal dysfunction in SSc patients. [ABSTRACT FROM AUTHOR]

Abstract Background Aquaporin-1 (AQP1), a water channel protein controlling the water contents of cells and tissues, exerts pleiotropic effects on various biological activities, including inflammation, angiogenesis, and extracellular matrix remodeling, by regulating cell behaviors and tissue water balance. Objective To investigate AQP1 roles in systemic sclerosis (SSc) which is characterized by autoimmune inflammation, vasculopathy, and tissue fibrosis. Methods AQP1 expression was evaluated by immunohistochemistry and quantitative reverse transcription PCR in skin samples from human and animal models and by immunoblotting in cultured cells. Fli1 binding to the AQP1 promoter was evaluated by chromatin immunoprecipitation. Cell migration was assessed by scratch assay. Results Dermal fibroblasts and endothelial cells highly expressed AQP1 in SSc lesional skin, and AQP1 expression in dermal fibroblasts and endothelial cells positively correlated with the degrees of tissue fibrosis and edema, respectively. Consistently, SSc dermal fibroblasts up-regulated AQP1 compared with normal dermal fibroblasts in vitro. Furthermore, TGF-β stimulation induced AQP1 expression in normal dermal fibroblasts, while TGF-β1 antisense oligonucleotide suppressed AQP1 expression in SSc dermal fibroblasts. In endothelial cells, Fli1 deficiency resulted in AQP1 up-regulation in vivo and in vitro and Fli1 bound to the AQP1 promoter. Importantly, SSc dermal fibroblasts and FLI1 siRNA-treated endothelial cells had a pro-migratory property, which was remarkably diminished by gene silencing of AQP1. Conclusion AQP1 is up-regulated in SSc dermal fibroblasts and SSc endothelial cells at least partially due to autocrine TGF-β stimulation and Fli1 deficiency, respectively, possibly contributing to inflammation, vasculopathy, and tissue fibrosis by regulating tissue edema and cell migration. [ABSTRACT FROM AUTHOR]

Abstract: CXCL13, a chemokine for B cells, follicular T cells, T helper 17 cells, and regulatory T cells, is reported to contribute to the development of systemic sclerosis (SSc), reflecting aberrant activation of immune system. To better understand the role of CXCL13 in SSc, we investigated the influence of Fli1 deficiency, a potential predisposing factor of this disease, on CXCL13 expression and assessed the clinical correlation of serum CXCL13 levels by multivariate regression analysis. Haploinsufficient loss of Fli1 remarkably induced CXCL13 expression in murine peritoneal macrophages, while gene silencing of FLI1 did not affect the expression of CXCL13 in human dermal fibroblasts and human dermal microvascular endothelial cells. Serum CXCL13 levels were elevated in SSc patients compared with healthy controls and correlated positively with skin score and negatively with pulmonary function test results. SSc patients with elevated serum CXCL13 levels had longer disease duration, diffuse cutaneous involvement, interstitial lung disease (ILD), heart involvement, pulmonary arterial hypertension, Raynaud's phenomenon, pitting scars, digital ulcers, telangiectasia, and high serum IgG levels more frequently than the other patients. In particular, serum CXCL13 levels were associated with ILD and digital ulcers by multivariate regression analysis. Taken together, these results indicate that CXCL13 expression is upregulated by Fli1 deficiency in macrophages, potentially contributing to the development of tissue fibrosis, vasculopathy and immune activation in SSc, especially ILD and digital ulcers. [ABSTRACT FROM AUTHOR]

Leukemia inhibitory factor (LIF) is a member of IL-6 family, which serves as a potent chemoattractant for neutrophils as well as a potent angiostatic factor. LIF has been implicated in various autoimmune inflammatory diseases, but its role still remains elusive in systemic sclerosis (SSc). Therefore, we investigated the potential role of LIF in the development of SSc by evaluating the clinical correlation of serum LIF levels, the expression of LIF and its receptors in skin samples, and in vitro experiments with human dermal microvascular endothelial cells. Serum LIF levels were significantly decreased in patients with SSc, especially in those with disease duration of < 1 year compared with healthy controls. As for clinical correlation, SSc patients with digital ulcers exhibited serum LIF levels significantly lower than those without. In immunohistochemistry, the expression of LIF and its receptors, LIF receptor and gp130, was remarkably decreased in dermal blood vessels of SSc lesional skin relative to those of healthy control skin. Furthermore, gene silencing of transcription factor Fli1, whose deficiency is involved in the development of SSc vasculopathy, suppressed the expression of LIF, LIF receptor, and gp130 and Fli1 bound to the promoters of those genes in human dermal microvascular endothelial cells. Collectively, these results suggest that decreased serum LIF levels may be associated with vasculopathy in SSc and that Fli1 deficiency may contribute to the inhibition of LIF-dependent biological effects on SSc endothelial cells by suppressing the expression of LIF, LIF receptor, and gp130. [ABSTRACT FROM AUTHOR]

Objective To determine the function and serum levels of soluble forms of programmed death 1 (sPD-1) and one of its ligands, soluble PD ligand 2 (sPD-L2), in patients with systemic sclerosis (SSc) and in a mouse model of topoisomerase I (topo I)-induced SSc. Methods Serum levels of sPD-1 and sPD-L2 in 91 patients with SSc were examined by enzyme-linked immunosorbent assay (ELISA). Expression of PD-1 and PD-L2 on T cells, B cells, and macrophages was quantified by flow cytometry. The effects of blockade of PD-1 and PD-L2 were analyzed by microfluidic ELISA (micro-ELISA), a technique that can measure very low amounts of cytokines. In addition, the effects of sPD-1 and sPD-L2 on disease progression were assessed in mice with topo I-induced SSc. Results Serum levels of sPD-1 and sPD-L2 were elevated in patients with SSc and correlated with the extent of fibrosis and immunologic abnormalities. Expression levels of PD-1 and PD-L2 were significantly elevated on SSc T cells, B cells, and macrophages. Micro-ELISA analysis of serum samples from patients with SSc showed that PD-L2high B cells had higher levels of interleukin-10 (IL-10) production compared with PD-L2low B cells, indicating that PD-L2 acts as a regulator of T cell cytokine production via cognate interactions with T cells and B cells. In mice with topo I-induced SSc, production of IL-10 by topo I-specific B cells in cultures with T cells and topo I protein was significantly higher than that by conventional B cells, and intraperitoneal injection of recombinant chimeric PD-1-Fc and PD-L2-Fc canceled these enhanced effects. Conclusion These results suggest that sPD-1 and sPD-L2 contribute to disease development in SSc via the regulation of cognate interactions with T cells and B cells. [ABSTRACT FROM AUTHOR]

Cathepsin L ( CTSL) is a lysosomal proteolytic enzyme involved in inflammation and vascular and extracellular matrix remodelling, which are the three cardinal pathological events associated with systemic sclerosis ( SSc). To elucidate the potential role of CTSL in the development of SSc, we here investigated CTSL expression in the lesional skin of patients with SSc and SSc animal models and the clinical correlation of serum CTSL levels. CTSL expression was elevated in dermal small vessels of SSc patients compared with those of healthy controls. Consistently, CTSL mRNA levels were increased in SSc lesional skin samples, but not in cultivated SSc dermal fibroblasts, compared with corresponding control samples from healthy individuals. Serum CTSL levels were significantly higher in SSc patients than in healthy controls and inversely correlated with skin score. Furthermore, the elevation of serum CTSL levels was linked to SSc vasculopathy. Supporting these results, Ctsl mRNA levels were decreased in the skin of bleomycin-treated mice, an SSc animal model recapitulating its fibrotic aspect, and CTSL expression was enhanced in dermal small vessels of endothelial cell-specific Fli1 knockout mice, reminiscent of SSc vasculopathy. Importantly, gene silencing of FLI1 induced CTSL mRNA expression and Fli1 occupied the CTSL promoter in human dermal microvascular endothelial cells. Collectively, these results suggest that endothelial CTSL up-regulation partially due to Fli1 deficiency may contribute to the development of vasculopathy, while the decrease in dermal CTSL expression is likely associated with dermal fibrosis in SSc. [ABSTRACT FROM AUTHOR]

Objective It is generally accepted that blockade of endothelin receptors has potentially beneficial effects on vasculopathy associated with systemic sclerosis (SSc). The aim of this study was to clarify the molecular mechanism underlying these effects using endothelial cell-specific Fli-1-knockout (Fli-1 ECKO) mice, an animal model of SSc vasculopathy. Methods Levels of messenger RNA for target genes and the expression and phosphorylation levels of target proteins were determined in human and murine dermal microvascular endothelial cells by real-time quantitative reverse transcription-polymerase chain reaction and immunoblotting, respectively. The binding of Fli-1 to the target gene promoters was evaluated using chromatin immunoprecipitation. Expression levels of Fli-1 and α-smooth muscle actin in murine skin were evaluated using immunohistochemistry. Vascular structure and permeability were evaluated in mice injected with fluorescein isothiocyanate-dextran and Evans blue dye, respectively. Results In human dermal microvascular endothelial cells, endothelin 1 induced phosphorylation of Fli-1 at Thr312 through the sequential activation of c-Abl and protein kinase Cδ, leading to a decrease in Fli-1 protein levels as well as a decrease in binding of Fli-1 to the target gene promoters, whereas bosentan treatment reversed those effects. In Fli-1 ECKO mice, 4 weeks of treatment with bosentan increased endothelial Fli-1 expression, resulting in vascular stabilization and the restoration of impaired leaky vessels. Conclusion The vascular fragility of Fli-1 ECKO mice was improved by bosentan through the normalization of Fli-1 protein levels and activity in endothelial cells, which may explain, in part, the mechanism underlying the beneficial effects of endothelin receptor blockade on SSc vasculopathy. [ABSTRACT FROM AUTHOR]

CCN1 is a pleiotropic molecule involved in angiogenesis and postnatal vasculogenesis, both of which are impaired in systemic sclerosis ( SSc). To elucidate the potential role of CCN1 in the development of SSc, we investigated CCN1 expression in the lesional skin of SSc patients and SSc animal models and the clinical correlation of serum CCN1 levels. CCN1 expression was markedly decreased in dermal small blood vessels of SSc patients compared with those of healthy controls, while comparable between normal and SSc dermal fibroblasts. Transcription factor Fli1, whose deficiency due to epigenetic suppression is implicated in the pathogenesis of SSc, occupied the CCN1 promoter and gene silencing of Fli1 resulted in the reduction of CCN1 expression in human dermal microvascular endothelial cells. Consistently, CCN1 expression was suppressed uniformly and remarkably in dermal blood vessels of Fli1+/− mice and partially in those of endothelial cell-specific Fli1 knockout mice. Furthermore, serum CCN1 levels were significantly decreased in SSc patients with previous and current history of digital ulcers as compared to those without. Collectively, these results suggest that endothelial CCN1 downregulation at least partially due to Fli1 deficiency may contribute to the development of digital ulcers in SSc patients. This study further supports the idea that epigenetic downregulation of Fli1 is a potential predisposing factor in the pathogenesis of SSc. [ABSTRACT FROM AUTHOR]

Herein we describe the clinical course of a case of idiopathic portal hypertension accompanied by splenomegaly, portal hypertension, and pancytopenia in addition to progressive systemic sclerosis. Immunological studies revealed positive antinuclear antibodies, hypergammaglobulinemia with increases in IgG and IgA, a decrease in peripheral T lymphocytes, and a decrease in the rate of lymphocyte blast transformation induced with phytohemagglutinin. The spleen weighed 1070 g, and the portal pressure was 270 mm H2O. Esophageal varices were also noted. These findings suggest the possibility of association of some immunological abnormalities with the etiology of idiopathic portal hypertension. [ABSTRACT FROM AUTHOR]

Background Scleroderma is a chronic disease of unknown etiology characterized by skin fibrosis and is divided into two clinical entities: systemic sclerosis (SSc) and localized scleroderma (LSc). In general, LSc is rarely complicated with SSc, but a certain portion of SSc patients manifests bilateral symmetric LSc-like lesions on the trunk and extremities. Objective We investigated SSc patients with LSc-like lesions to clarify the underlying pathophysiology. Methods Nine SSc cases complicated with LSc-like lesions were clinically and histologically characterized. Results SSc patients with LSc-like lesions exhibited multiple progressive hyper- and/or hypo-pigmented plaques with mild sclerosis symmetrically distributed on the trunk and extremities, especially abdominal region. In histological assessment, epidermal IL-1α expression was elevated in both forearms and LSc-like lesions of these patients to a greater extent than in forearms of control patients (SSc patients without LSc-like lesions). Of note, the infiltration and degranulation of mast cells were evident throughout the dermis of LSc-like lesions, while detectable to a lesser extent in forearms of SSc patients with LSc-like lesions and control patients. Conclusion The epidermis of SSc patients with LSc-like lesions seems to possess an inflammatory phenotype, leading to the activation of mast cells in the dermis of mechanically stressed skin. Köbner phenomenon may be involved in the induction of LSc-like lesions in a certain subset of SSc. [ABSTRACT FROM AUTHOR]

• RALDH1+CD11b−CD103− murine dermal DCs regulate skin fibrosis via Treg induction. • RALDH1-producing dermal DCs are decreased in the involved skin of SSc patients. • RALDH1-producing dermal DCs may regulate inducible Tregs in skin fibrotic disorders. Skin fibrosis of systemic sclerosis (SSc) is believed to be driven by complex processes including immune abnormalities, but the underlying immune response remains enigmatic. In particular, the role of dermal dendritic cells (DCs) is totally unknown. We investigated the impact of CD103 loss on bleomycin-induced skin fibrosis because CD103 is a critical molecule determining DC phenotypes. Bleomycin-induced skin fibrosis was generated with Cd103 −/− mice. The alterations of tissue fibrosis and related inflammation were investigated by histologic examination, hydroxyproline assay, quantitative reverse transcription PCR and flow cytometry. SSc skin samples were evaluated by immunofluorescence. CD103 loss decreased bleomycin-induced dermal thickness and collagen contents, along with TGF-β1 and CTGF suppression. Treg proportion was increased, while Th1/Th2/Th17 cell proportions were decreased in the skin of bleomycin-treated Cd103 −/− mice. Bleomycin injection enhanced CD11b-CD103- DC proportion in wild-type mice, which was further augmented in Cd103 −/− mice. Importantly, RALDH1/ALDH1A1 enzyme oxidizing retinaldehyde to retinoic acid, an inducer of Tregs, was preferentially expressed by CD11b-CD103- DCs and its expression levels were elevated in bleomycin-injected skin lesions, to a greater extent in Cd103 −/− mice than in wild-type mice. Importantly, the number of RALDH1-positive DCs was decreased in the lesional skin of SSc patients and tended to inversely correlate with skin fibrosis severity. This study identified a critical role of dermal DCs as a regulator of Treg development through RALDH1 in bleomycin-treated mice and possibly in human SSc. This finding sheds new light on dermal DCs as a new therapeutic target of SSc. [ABSTRACT FROM AUTHOR]