COL1A1 proximal promoter topology regulates its transcriptional response to transforming growth factor ß.

OBJECTIVE: The COL1A1 proximal promoter contains two GC-rich regions and two inverted CCAAT boxes. The transcription factors Sp1 and CBF bind to the GC sequence at -122 to -115 bp and the inverted CCAAT box at -101 to -96 bp, respectively, and stimulate COL1A1 transcriptional activity. METHODS: To further define the regulatory mechanisms controlling COL1A1 expression by Sp1 and CBF, we introduced 2, 4, 6, or 8 thymidine nucleotides (T-tracts) at position -111 bp of the COL1A1 gene promoter to increase the physical distance between these two binding sites and examined in vitro the transcriptional activities of the resulting constructs and their response to TGF-ß1.`. RESULTS: Insertion of 2 or 4 nucleotides decreased COL1A1 promoter activity by up to 70%. Furthermore, the expected increase in COL1A1 transcription in response to TGF-ß1 was abolished. Computer modeling of the modified DNA structure indicated that increasing the physical distance between the Sp1 and CBF binding sites introduces a rotational change in the DNA topology that disrupts the alignment of Sp1 and CBF binding sites and likely alters protein-protein interactions among these transcription factors or their associated co-activators. CONCLUSION: The topology of the COL1A1 proximal promoter is crucial in determining the transcriptional activity of the gene and its response to the stimulatory effects of TGF-ß1.

Cellular Transdifferentiation: A Crucial Mechanism of Fibrosis in Systemic Sclerosis.

Systemic Sclerosis (SSc) is a systemic autoimmune disease of unknown etiology with a highly complex pathogenesis that despite extensive investigation is not completely understood. The clinical and pathologic manifestations of the disease result from three distinct processes: 1) Severe and frequently progressive tissue fibrosis causing exaggerated and deleterious accumulation of interstitial collagens and other extracellular matrix molecules in the skin and various internal organs; 2) extensive fibroproliferative vascular lesions affecting small arteries and arterioles causing tissue ischemic alterations; and 3) cellular and humoral immunity abnormalities with the production of numerous autoantibodies, some with very high specificity for SSc. The fibrotic process in SSc is one of the main causes of disability and high mortality of the disease. Owing to its essentially universal presence and the severity of its clinical effects, the mechanisms involved in the development and progression of tissue fibrosis have been extensively investigated, however, despite intensive investigation, the precise molecular mechanisms have not been fully elucidated. Several recent studies have suggested that cellular transdifferentiation resulting in the phenotypic conversion of various cell types into activated myofibroblasts may be one important mechanism. Here, we review the potential role that cellular transdifferentiation may play in the development of severe and often progressive tissue fibrosis in SSc.

Pharmacological treatment of systemic sclerosis-associated interstitial lung disease: an updated review and current approach to patient care.

Interstitial lung disease (ILD) has a high prevalence among patients with systemic sclerosis (SSc), carrying high mortality and morbidity. During the last decade, the emergence of new pharmacological therapies for SSc-associated ILD (SSc-ILD) and improved tools for its diagnosis and monitoring have changed the prevailing clinical approach, highlighting the need for early recognition and prompt treatment for SSc-ILD. Furthermore, the recent approval of multiple therapies for SSc-ILD poses challenges for the rheumatologist and pulmonologist in choosing the appropriate therapy for individual clinical scenarios. We review the pathophysiology of SSc-ILD, and the mechanisms of action and rationale behind current therapies. We also review the evidence of the efficacy and safety of immunosuppressive drugs, antifibrotic agents, and immunomodulators from cyclophosphamide and mycophenolate to novel agents such as nintedanib and tocilizumab. We also emphasise the importance of early diagnosis and monitoring and describe our approach to pharmacological therapy for SSc-ILD patients.

Probable role of exosomes in the extension of fibrotic alterations from affected to normal cells in systemic sclerosis.

SSc is a systemic autoimmune disease of unknown etiology characterized by frequently progressive cutaneous and internal organ fibrosis causing severe disability, organ failure and high mortality. A remarkable feature of SSc is the extension of the fibrotic alterations to nonaffected tissues. The mechanisms involved in the extension of fibrosis have remained elusive. We propose that this process is mediated by exosome microvesicles released from SSc-affected cells that induce an activated profibrotic phenotype in normal or nonaffected cells. Exosomes are secreted microvesicles involved in an intercellular communication system. Exosomes can transfer their macromolecular content to distant target cells and induce paracrine effects in the recipient cells, changing their molecular pathways and gene expression. Confirmation of this hypothesis may identify the molecular mechanisms responsible for extension of the SSc fibrotic process from affected cells to nonaffected cells and may allow the development of novel therapeutic approaches for the disease.

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.

Treatment of Severe Swallowing Dysfunction in Systemic Sclerosis with IVIG: Role of Antimuscarinic Antibodies.

Oropharyngeal and esophageal dysmotility can cause serious clinical complications such as aspiration pneumonia, cachexia, and sarcopenia, with a resulting increase in mortality and disability. The current standard of care for the treatment of SSc-associated swallowing dysfunction is mainly supportive, although severe cases are usually refractory to conventional management. Recent studies have shown that the abnormal production of functional autoantibodies such as anti-cholinergic muscarinic receptor III antibodies may participate in the pathogenesis of SSc-associated gastrointestinal dysmotility and may provide a novel target for therapeutic intervention. We describe two patients with severe and rapid onset of SSc-associated severe swallowing dysfunction and esophageal dysmotility who had failed standard of care therapy, requiring complete enteral and parenteral nutrition. Both patients were positive for the presence of circulating antimuscarinic III receptor antibodies. They were treated with IVIG at a dose of 2 g/Kg/month divided in two consecutive days, for six months. Following IVIG therapy, both patients markedly improved their symptoms as shown by a reduction in their UCLA2.0 score, and achieved an improvement of esophageal motility documented radiologically. Both patients resumed oral feeding and had their feeding tubes removed within the treatment period. None of the patients developed severe adverse events attributable to IVIG, except for low-grade fever during IVIG infusion in one of the cases. These results provide support for the role of functional autoantibodies in the development of SSc-associated gastrointestinal dysfunction.

Progressive multifocal fibrosing neuropathy: description of a novel disease.

Entrapment peripheral neuropathies are clinically characterized by sensory impairment and motor deficits. They are usually caused by mechanical injuries, but they are also a frequent manifestation of metabolic diseases, toxic agent exposure, or systemic fibrotic disorders. Here we describe the clinical, radiological, and histopathological features of a novel progressive fibrotic disorder characterized by progressive multifocal fibrosing neuropathy. We identified two patients who presented with severe and progressive peripheral neuropathic symptoms sequentially affecting multiple sites. These patients presented with severe and progressive multifocal, sequentially additive peripheral neuropathic symptoms. Extensive nerve conduction and radiological studies showed the sequential development of multifocal motor and sensory peripheral neuropathy in the absence of any exposure to known infectious, inflammatory, or fibrotic triggers and the lack of family history of compression neuropathies. Extensive clinical and laboratory test evaluation failed to support the diagnosis of any primary inflammatory or genetic peripheral neuropathy and there was no evidence of any systemic fibrosing disorder including Systemic Sclerosis, lacking cutaneous fibrotic changes and cardiopulmonary abnormalities. The clinical course was progressive with sequential development of motor and sensory deficits of upper and lower extremities displaying proximal predominance. Histopathological study of tissues obtained during nerve release surgeries showed severe perineural fibrosis with marked accumulation of thick collagen bundles encroaching the peripheral nerves. There was no evidence of vasculitic, inflammatory, or vascular fibroproliferative lesions. We suggest that the clinical findings described here represent a previously undescribed fibrotic disorder affecting peripheral nerves, and we propose the descriptive term "Progressive Multifocal Fibrosing Neuropathy" to refer to this novel disorder. Despite the inherent limitations of this early description, we hope this is would contribute to the identification of additional cases.

Serine/threonine kinase inhibition as antifibrotic therapy: transforming growth factor-ß and Rho kinase inhibitors.

Serine/threonine kinases mediate the phosphorylation of intracellular protein targets, transferring a phosphorus group from an adenosine triphosphate molecule to the specific amino acid residues within the target proteins. Serine/threonine kinases regulate multiple key cellular functions. From this large group of kinases, TGF-ß through serine/threonine activity of its receptors and Rho kinase (ROCK) play an important role in the development and maintenance of fibrosis in various human diseases, including SSc. In recent years, multiple drugs targeting and inhibiting these kinases have been developed, opening the possibility of becoming potential antifibrotic agents of clinical value for treating fibrotic diseases. This review analyses the contribution of TGF-ß and ROCK-mediated serine/threonine kinase molecular pathways to the development and maintenance of pathological fibrosis and the potential clinical use of their inhibition.

Oxidative Stress Induced by Reactive Oxygen Species (ROS) and NADPH Oxidase 4 (NOX4) in the Pathogenesis of the Fibrotic Process in Systemic Sclerosis: A Promising Therapeutic Target.

Numerous clinical and research investigations conducted during the last two decades have implicated excessive oxidative stress caused by high levels of reactive oxygen species (ROS) in the development of the severe and frequently progressive fibrotic process in Systemic Sclerosis (SSc). The role of excessive oxidative stress in SSc pathogenesis has been supported by the demonstration of increased levels of numerous biomarkers, indicative of cellular and molecular oxidative damage in serum, plasma, and other biological fluids from SSc patients, and by the demonstration of elevated production of ROS by various cell types involved in the SSc fibrotic process. However, the precise mechanisms mediating oxidative stress development in SSc and its pathogenetic effects have not been fully elucidated. The participation of the NADPH oxidase NOX4, has been suggested and experimentally supported by the demonstration that SSc dermal fibroblasts display constitutively increased NOX4 expression and that reduction or abrogation of NOX4 effects decreased ROS production and the expression of genes encoding fibrotic proteins. Furthermore, NOX4-stimulated ROS production may be involved in the development of certain endothelial and vascular abnormalities and may even participate in the generation of SSc-specific autoantibodies. Collectively, these observations suggest NOX4 as a novel therapeutic target for SSc.

Global gene expression analysis of systemic sclerosis myofibroblasts demonstrates a marked increase in the expression of multiple NBPF genes.

Myofibroblasts are the key effector cells responsible for the exaggerated tissue fibrosis in Systemic Sclerosis (SSc). Despite their importance to SSc pathogenesis, the specific transcriptome of SSc myofibroblasts has not been described. The purpose of this study was to identify transcriptome differences between SSc myofibroblasts and non-myofibroblastic cells. Alpha smooth muscle actin (α-SMA) expressing myofibroblasts and α-SMA negative cells were isolated employing laser capture microdissection from dermal cell cultures from four patients with diffuse SSc of recent onset. Total mRNA was extracted from both cell populations, amplified and analyzed employing microarrays. Results for specific genes were validated by Western blots and by immunohistochemistry. Transcriptome analysis revealed 97 differentially expressed transcripts in SSc myofibroblasts compared with non-myofibroblasts. Annotation clustering of the SSc myofibroblast-specific transcripts failed to show a TGF-ß signature. The most represented transcripts corresponded to several different genes from the Neuroblastoma Breakpoint Family (NBPF) of genes. NBPF genes are highly expanded in humans but are not present in murine or rat genomes. In vitro studies employing cultured SSc dermal fibroblasts and immunohistochemistry of affected SSc skin confirmed increased NBPF expression in SSc. These results indicate that SSc myofibroblasts represent a unique cell lineage expressing a specific transcriptome that includes very high levels of transcripts corresponding to numerous NBPF genes. Elevated expression of NBPF genes in SSc myofibroblasts suggests that NBPF gene products may play a role in SSc pathogenesis and may represent a novel therapeutic target.

Tyrosine kinases in the pathogenesis of tissue fibrosis in systemic sclerosis and potential therapeutic role of their inhibition.

Systemic sclerosis (SSc) is an idiopathic autoimmune disease with a heterogeneous clinical phenotype ranging from limited cutaneous involvement to rapidly progressive diffuse SSc. The most severe SSc clinical and pathologic manifestations result from an uncontrolled fibrotic process involving the skin and various internal organs. The molecular mechanisms responsible for the initiation and progression of the SSc fibrotic process have not been fully elucidated. Recently it has been suggested that tyrosine protein kinases play a role. The implicated kinases include receptor-activated tyrosine kinases and nonreceptor tyrosine kinases. The receptor kinases are activated following specific binding of growth factors (platelet-derived growth factor, fibroblast growth factor, or vascular endothelial growth factor). Other receptor kinases are the discoidin domain receptors activated by binding of various collagens, the ephrin receptors that are activated by ephrins and the angiopoetin-Tie-2s receptors. The nonreceptor tyrosine kinases c-Abl, Src, Janus, and STATs have also been shown to participate in SSc-associated tissue fibrosis. Currently, there are no effective disease-modifying therapies for SSc-associated tissue fibrosis. Therefore, extensive investigation has been conducted to examine whether tyrosine kinase inhibitors (TKIs) may exert antifibrotic effects. Here, we review the role of receptor and nonreceptor tyrosine kinases in the pathogenesis of the frequently progressive cutaneous and systemic fibrotic alterations in SSc, and the potential of TKIs as SSc disease-modifying antifibrotic therapeutic agents.

Increased expression of interferon regulated and antiviral response genes in CD31+/CD102+ lung microvascular endothelial cells from systemic sclerosis patients with end-stage interstitial lung disease.

OBJECTIVES: Systemic sclerosis (SSc) is characterised by severe fibroproliferative vasculopathy, fibrosis in skin and multiple internal organs, and humoral, cellular and innate immunity abnormalities. Vascular alterations are the earliest and most severe SSc manifestations, however, the mechanisms responsible have remained elusive. To investigate the molecular abnormalities involved in SSc-vasculopathy we examined global gene expression differences between highly purified lung microvascular endothelial cells (MVECs) from patients with SSc-interstitial lung disease (SSc-ILD) and normal lung MVECs. METHODS: MVECs were isolated from fresh transplanted lungs from patients with SSc-ILD. Sequential CD31 and CD102 immunopurification was performed to obtain highly purified CD31+/CD102+ lung MVECs. Global gene expression analysis was successfully performed in CD31+/CD102+ MVEC from two SSc-ILD patients and from two normal lungs. RT-PCR, Western blots, and indirect immunofluorescence validated the gene expression results. RESULTS: Numerous interferon-regulated genes (IRGs) including IFI44, IFI44L, IFI6, IFIH1, IFIT1, ISG-15, BST-2/Tetherin, and RSAD2/Viperin, genes encoding innate immunity antiviral responses (OAS1, OAS2, OAS3, OASL) and antiviral MX1 and MX2 proteins, and mesenchymal cell-specific genes were significantly overexpressed in CD31+/CD102+ SSc-ILD lung MVECs. CONCLUSIONS: Highly purified CD31+/CD102+ MVECs from lungs from SSc patients with end stage SSc-ILD displayed remarkable overexpression of numerous IRGs and of genes encoding antiviral innate immune response and antiviral proteins. These observations suggest that interferon-induced and antiviral response proteins may participate in the pathogenesis of SSc vasculopathy and SSc-ILD. The CD31+/CD102+ lung MVECs from SSc-ILD also showed elevated expression of mesenchymal cell-specific genes confirming the presence of endothelial to mesenchymal transition in SSc-ILD.

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

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

Molecular characteristics and functional differences of anti-PM/Scl autoantibodies and two other distinct and unique supramolecular structures known as "EXOSOMES".

The term "exosome" has been applied to three distinct supramolecular entities, namely the PM/Scl autoantibodies or "RNA exosomes", transforming DNA fragments termed "DNA exosomes", and small size extracellular vesicles knows as "exosomes". Some of the molecular components of the "PM/Scl exosome complex" or "RNA exosome" are recognized by specific autoantibodies present in the serum from some Systemic Sclerosis (SSc), polymyositis (PM) and polymyositis SSc (PM/Scl) overlap syndrome patients. On the other hand, one of the most active focuses of laboratory investigation in the last decade has been the biogenesis and role of extracellular vesicles known as "exosomes". The remarkable ability of these "exosome" vesicles to alter the cellular phenotype following fusion with target cells and the release of their macromolecular cargo has revealed a possible role in the pathogenesis of numerous diseases, including malignant, inflammatory, and autoimmune disorders and may allow them to serve as theranostic agents for personalized and precision medicine. The indiscriminate use of the term "exosome" to refer to these three distinct molecular entities has engendered great confusion in the scientific literature. Here, we review the molecular characteristics and functional differences between the three molecular structures identified as "exosomes". Given the rapidly growing scientific interest in extravesicular exosomes, unless a solution is found the confusion in the literature resulting from the use of the term "exosomes" will markedly increase.

Increased expression of the transforming growth factor ß-inducible gene HIC-5 in systemic sclerosis skin and fibroblasts: a novel antifibrotic therapeutic target.

OBJECTIVE: SSc is a systemic fibrotic disease affecting skin, numerous internal organs and the microvasculature. The molecular pathogenesis of SSc tissue fibrosis has not been fully elucidated, although TGF-ß1 plays a crucial role. The Hic-5 protein encoded by the TGF-ß1-inducible HIC-5 gene participates in numerous TGF-ß-mediated pathways, however, the role of Hic-5 in SSc fibrosis has not been investigated. The aim of this study was to examine HIC-5 involvement in SSc tissue fibrosis. METHODS: Affected skin from three patients with diffuse SSc and dermal fibroblasts cultured from affected and non-affected SSc skin were examined for HIC-5 and COL1A1 gene expression. Real-time PCR, IF microscopy, western blotting and small interfering RNA-mediated HIC-5 were performed. RESULTS: HIC-5 and COL1A1 transcripts and Hic-5, type 1 collagen (COL1) and α-smooth muscle actin (α-SMA) protein levels were increased in clinically affected SSc skin compared with normal skin and in cultured dermal fibroblasts from affected SSc skin compared with non-affected skin fibroblasts from the same patients. HIC-5 knockdown caused a marked reduction of COL1 production in SSc dermal fibroblasts. CONCLUSION: HIC-5 expression is increased in affected SSc skin compared with skin from normal individuals. Affected SSc skin fibroblasts display increased HIC-5 and COL1A1 expression compared with non-affected skin fibroblasts from the same patients. Hic-5 protein was significantly increased in cultured SSc dermal fibroblasts. HIC-5 mRNA knockdown in SSc fibroblasts caused >50% reduction of COL1 production. Although these are preliminary results owing to the small number of skin samples studied, they indicate that Hic-5 plays a role in the profibrotic activation of SSc dermal fibroblasts and may represent a novel molecular target for antifibrotic therapy in SSc.

Long non-coding RNA HOTAIR drives EZH2-dependent myofibroblast activation in systemic sclerosis through miRNA 34a-dependent activation of NOTCH.

BACKGROUND: Systemic sclerosis (SSc) is characterised by autoimmune activation, tissue and vascular fibrosis in the skin and internal organs. Tissue fibrosis is driven by myofibroblasts, that are known to maintain their phenotype in vitro, which is associated with epigenetically driven trimethylation of lysine 27 of histone 3 (H3K27me3). METHODS: Full-thickness skin biopsies were surgically obtained from the forearms of 12 adult patients with SSc of recent onset. Fibroblasts were isolated and cultured in monolayers and protein and RNA extracted. HOX transcript antisense RNA (HOTAIR) was expressed in healthy dermal fibroblasts by lentiviral induction employing a vector containing the specific sequence. Gamma secretase inhibitors were employed to block Notch signalling. Enhancer of zeste 2 (EZH2) was blocked with GSK126 inhibitor. RESULTS: SSc myofibroblasts in vitro and SSc skin biopsies in vivo display high levels of HOTAIR, a scaffold long non-coding RNA known to direct the histone methyltransferase EZH2 to induce H3K27me3 in specific target genes. Overexpression of HOTAIR in dermal fibroblasts induced EZH2-dependent increase in collagen and α-SMA expression in vitro, as well as repression of miRNA-34A expression and consequent NOTCH pathway activation. Consistent with these findings, we show that SSc dermal fibroblast display decreased levels of miRNA-34a in vitro. Further, EZH2 inhibition rescued miRNA-34a levels and mitigated the profibrotic phenotype of both SSc and HOTAIR overexpressing fibroblasts in vitro. CONCLUSIONS: Our data indicate that the EZH2-dependent epigenetic phenotype of myofibroblasts is driven by HOTAIR and is linked to miRNA-34a repression-dependent activation of NOTCH signalling.

Recurrence of progressive skin involvement following discontinuation or dose reduction of Mycophenolate Mofetil treatment in patients with diffuse Systemic Sclerosis.

BACKGROUND: Rapidly progressive diffuse cutaneous Systemic Sclerosis (rp-dcSSc) is associated with severe internal organ involvement and high mortality. Mycophenolate Mofetil (MMF) has been shown to halt the progression of rp-dcSSc cutaneous and pulmonary involvement in observational and randomized controlled trials, respectively. However, optimal MMF therapy duration has not been established. Here, we describe the clinical evolution of rp-dcSSc patients successfully treated with MMF following MMF therapy discontinuation or dose reduction. METHODS: Twenty-five patients with recent-onset (< 24 mo) rp-dcSSc received MMF as the only SSc disease-modifying therapy. Following MMF discontinuation or dose reduction to or below 1000 mg/day after an average of two years, the Modified Rodnan skin score (mRSS) and Pulmonary function tests (PFT) were serially evaluated for additional 5 years. MMF therapy was re-instituted if the mRSS increased by greater than 20% or if restrictive lung disease developed. RESULTS: From nineteen patients serially evaluated following MMF discontinuation or dose reduction, five patients (26.3%) developed recurrence of rapid skin involvement with an average of 35.9% increase in mRSS from 7.8 to 10.6 points requiring MMF re-institution. Two of these patients also presented worsening respiratory symptoms and reduction of lung volumes in PFTs. Following MMF resumption, mRSS returned to baseline or stabilized and PFTs improved or stabilized. All these patients were maintained on high dose long term MMF treatment. CONCLUSION: Recurrence of severe skin involvement occurred in 26.3% of patients with rp-dcSSc following MMF discontinuation or dose reduction, requiring prompt MMF therapy resumption. These findings confirm the therapeutic benefit of MMF in rp-dcSSc and suggest that MMF treatment should be maintained for longer than 2 years.

Racial differences in systemic sclerosis disease presentation: a European Scleroderma Trials and Research group study.

OBJECTIVES: Racial factors play a significant role in SSc. We evaluated differences in SSc presentations between white patients (WP), Asian patients (AP) and black patients (BP) and analysed the effects of geographical locations. METHODS: SSc characteristics of patients from the EUSTAR cohort were cross-sectionally compared across racial groups using survival and multiple logistic regression analyses. RESULTS: The study included 9162 WP, 341 AP and 181 BP. AP developed the first non-RP feature faster than WP but slower than BP. AP were less frequently anti-centromere (ACA; odds ratio (OR) = 0.4, P < 0.001) and more frequently anti-topoisomerase-I autoantibodies (ATA) positive (OR = 1.2, P = 0.068), while BP were less likely to be ACA and ATA positive than were WP [OR(ACA) = 0.3, P < 0.001; OR(ATA) = 0.5, P = 0.020]. AP had less often (OR = 0.7, P = 0.06) and BP more often (OR = 2.7, P < 0.001) diffuse skin involvement than had WP. AP and BP were more likely to have pulmonary hypertension [OR(AP) = 2.6, P < 0.001; OR(BP) = 2.7, P = 0.03 vs WP] and a reduced forced vital capacity [OR(AP) = 2.5, P < 0.001; OR(BP) = 2.4, P < 0.004] than were WP. AP more often had an impaired diffusing capacity of the lung than had BP and WP [OR(AP vs BP) = 1.9, P = 0.038; OR(AP vs WP) = 2.4, P < 0.001]. After RP onset, AP and BP had a higher hazard to die than had WP [hazard ratio (HR) (AP) = 1.6, P = 0.011; HR(BP) = 2.1, P < 0.001]. CONCLUSION: Compared with WP, and mostly independent of geographical location, AP have a faster and earlier disease onset with high prevalences of ATA, pulmonary hypertension and forced vital capacity impairment and higher mortality. BP had the fastest disease onset, a high prevalence of diffuse skin involvement and nominally the highest mortality.

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

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

Endothelial to Mesenchymal Transition: Role in Physiology and in the Pathogenesis of Human Diseases.

Numerous studies have demonstrated that endothelial cells are capable of undergoing endothelial to mesenchymal transition (EndMT), a newly recognized type of cellular transdifferentiation. EndMT is a complex biological process in which endothelial cells adopt a mesenchymal phenotype displaying typical mesenchymal cell morphology and functions, including the acquisition of cellular motility and contractile properties. Endothelial cells undergoing EndMT lose the expression of endothelial cell-specific proteins such as CD31/platelet-endothelial cell adhesion molecule, von Willebrand factor, and vascular-endothelial cadherin and initiate the expression of mesenchymal cell-specific genes and the production of their encoded proteins including α-smooth muscle actin, extra domain A fibronectin, N-cadherin, vimentin, fibroblast specific protein-1, also known as S100A4 protein, and fibrillar type I and type III collagens. Transforming growth factor-ß1 is considered the main EndMT inducer. However, EndMT involves numerous molecular and signaling pathways that are triggered and modulated by multiple and often redundant mechanisms depending on the specific cellular context and on the physiological or pathological status of the cells. EndMT participates in highly important embryonic development processes, as well as in the pathogenesis of numerous genetically determined and acquired human diseases including malignant, vascular, inflammatory, and fibrotic disorders. Despite intensive investigation, many aspects of EndMT remain to be elucidated. The identification of molecules and regulatory pathways involved in EndMT and the discovery of specific EndMT inhibitors should provide novel therapeutic approaches for various human disorders mediated by EndMT.