Long Non-Coding RNAs Play a Role in the Pathogenesis of Psoriatic Arthritis by Regulating MicroRNAs and Genes Involved in Inflammation and Metabolic Syndrome.

Psoriatic arthritis (PsA) is an inflammatory arthritis, characterized by inflammation of entheses and synovium, leading to joint erosions and new bone formation. It affects 10-30% of patients with psoriasis, and has an estimated prevalence of approximately 1%. PsA is considered to be primarily an autoimmune disease, driven by autoreactive T cells directed against autoantigens present in the skin and in the joints. However, an autoinflammatory origin has recently been proposed. Long noncoding RNAs (lncRNAs) are RNAs more than 200 nucleotides in length that do not encode proteins. LncRNAs play important roles in several biological processes, including chromatin remodeling, transcription control, and post-transcriptional processing. Several studies have shown that lncRNAs are expressed in a stage-specific or lineage-specific manner in immune cells that have a role in the development, activation, and effector functions of immune cells. LncRNAs are thought to play a role in several diseases, including autoimmune disorders. Indeed, a few lncRNAs have been identified in systemic lupus erythematosus, rheumatoid arthritis, and psoriasis. Although several high-throughput studies have been performed to identify lncRNAs, their biological and pathological relevance are still unknown, and most transcriptome studies in autoimmune diseases have only assessed protein-coding transcripts. No data are currently available on lncRNAs in PsA. Therefore, by microarray analysis, we have investigated the expression profiles of more than 50,000 human lncRNAs in blood samples from PsA patients and healthy controls using Human Clariom D Affymetrix chips, suitable to detect rare and low-expressing transcripts otherwise unnoticed by common sequencing methodologies. Network analysis identified lncRNAs targeting highly connected genes in the PsA transcriptome. Such genes are involved in molecular pathways crucial for PsA pathogenesis, including immune response, glycolipid metabolism, bone remodeling, type 1 interferon, wingless related integration site, and tumor necrosis factor signaling. Selected lncRNAs were validated by RT-PCR in an expanded cohort of patients. Moreover, modulated genes belonging to meaningful pathways were validated by RT-PCR in PsA PBMCs and/or by ELISA in PsA sera. The findings indicate that lncRNAs are involved in PsA pathogenesis by regulating both microRNAs and genes and open new avenues for the identification of new biomarkers and therapeutical targets.

MicroRNA Expression Profiling in Behçet's Disease.

BACKGROUND: Behçet's disease (BD) is a chronic inflammatory multisystem disease characterized by oral and genital ulcers, uveitis, and skin lesions. MicroRNAs (miRNAs) are key regulators of immune responses. Differential expression of miRNAs has been reported in several inflammatory autoimmune diseases; however, their role in BD is not fully elucidated. We aimed to identify miRNA expression signatures associated with BD and to investigate their potential implication in the disease pathogenesis. METHODS: miRNA microarray analysis was performed in blood cells of BD patients and healthy controls. miRNA expression profiles were analyzed using Affymetrix arrays with a comprehensive coverage of miRNA sequences. Pathway analyses were performed, and the global miRNA profiling was combined with transcriptoma data in BD. Deregulation of selected miRNAs was validated by real-time PCR. RESULTS: We identified specific miRNA signatures associated with BD patients with active disease. These miRNAs target pathways relevant in BD, such as TNF, IFN gamma, and VEGF-VEGFR signaling cascades. Network analysis revealed several miRNAs regulating highly connected genes within the BD transcriptoma. CONCLUSIONS: The combined analysis of deregulated miRNAs and BD transcriptome sheds light on some epigenetic aspects of BD identifying specific miRNAs, which may represent promising candidates as biomarkers and/or for the design of novel therapeutic strategies in BD.

Gene Expression Profiling in Behcet's Disease Indicates an Autoimmune Component in the Pathogenesis of the Disease and Opens New Avenues for Targeted Therapy.

Behçet disease (BD) is a chronic inflammatory multisystem disease characterized by oral and genital ulcers, uveitis, and skin lesions. Disease etiopathogenesis is still unclear. We aim to elucidate some aspects of BD pathogenesis and to identify specific gene signatures in peripheral blood cells (PBCs) of patients with active disease using novel gene expression and network analysis. 179 genes were modulated in 10 PBCs of BD patients when compared to 10 healthy donors. Among differentially expressed genes the top enriched gene function was immune response, characterized by upregulation of Th17-related genes and type I interferon- (IFN-) inducible genes. Th17 polarization was confirmed by FACS analysis. The transcriptome identified gene classes (vascular damage, blood coagulation, and inflammation) involved in the pathogenesis of the typical features of BD. Following network analysis, the resulting interactome showed 5 highly connected regions (clusters) enriched in T and B cell activation pathways and 2 clusters enriched in type I IFN, JAK/STAT, and TLR signaling pathways, all implicated in autoimmune diseases. We report here the first combined analysis of the transcriptome and interactome in PBCs of BD patients in the active stage of disease. This approach generates useful insights in disease pathogenesis and suggests an autoimmune component in the origin of BD.

MicroRNA Expression Profiling in Psoriatic Arthritis.

BACKGROUND: Psoriatic arthritis (PsA) is an inflammatory arthritis, characterized by bone erosions and new bone formation. MicroRNAs (miRNAs) are key regulators of the immune responses. Differential expression of miRNAs has been reported in several inflammatory autoimmune diseases; however, their role in PsA is not fully elucidated. We aimed to identify miRNA expression signatures associated with PsA and to investigate their potential implication in the disease pathogenesis. METHODS: miRNA microarray was performed in blood cells of PsA patients and healthy controls. miRNA pathway analyses were performed and the global miRNA profiling was combined with transcriptome data in PsA. Deregulation of selected miRNAs was validated by real-time PCR. RESULTS: We identified specific miRNA signatures associated with PsA patients with active disease. These miRNAs target pathways relevant in PsA, such as TNF, MAPK, and WNT signaling cascades. Network analysis revealed several miRNAs regulating highly connected genes within the PsA transcriptome. miR-126-3p was the most downregulated miRNA in active patients. Noteworthy, miR-126 overexpression induced a decreased expression of genes implicated in PsA. CONCLUSIONS: This study sheds light on some epigenetic aspects of PsA identifying specific miRNAs, which may represent promising candidates as biomarkers and/or for the design of novel therapeutic strategies in PsA.

Gene Profiling in Patients with Systemic Sclerosis Reveals the Presence of Oncogenic Gene Signatures.

Systemic sclerosis (SSc) is a rare connective tissue disease characterized by three pathogenetic hallmarks: vasculopathy, dysregulation of the immune system, and fibrosis. A particular feature of SSc is the increased frequency of some types of malignancies, namely breast, lung, and hematological malignancies. Moreover, SSc may also be a paraneoplastic disease, again indicating a strong link between cancer and scleroderma. The reason of this association is still unknown; therefore, we aimed at investigating whether particular genetic or epigenetic factors may play a role in promoting cancer development in patients with SSc and whether some features are shared by the two conditions. We therefore performed a gene expression profiling of peripheral blood mononuclear cells (PBMCs) derived from patients with limited and diffuse SSc, showing that the various classes of genes potentially linked to the pathogenesis of SSc (such as apoptosis, endothelial cell activation, extracellular matrix remodeling, immune response, and inflammation) include genes that directly participate in the development of malignancies or that are involved in pathways known to be associated with carcinogenesis. The transcriptional analysis was then complemented by a complex network analysis of modulated genes which further confirmed the presence of signaling pathways associated with carcinogenesis. Since epigenetic mechanisms, such as microRNAs (miRNAs), are believed to play a central role in the pathogenesis of SSc, we also evaluated whether specific cancer-related miRNAs could be deregulated in the serum of SSc patients. We focused our attention on miRNAs already found upregulated in SSc such as miR-21-5p, miR-92a-3p, and on miR-155-5p, miR 126-3p and miR-16-5p known to be deregulated in malignancies associated to SSc, i.e., breast, lung, and hematological malignancies. miR-21-5p, miR-92a-3p, miR-155-5p, and miR-16-5p expression was significantly higher in SSc sera compared to healthy controls. Our findings indicate the presence of modulated genes and miRNAs that can play a predisposing role in the development of malignancies in SSc and are important for a better risk stratification of patients and for the identification of a better individualized precision medicine strategy.

Gene Expression Analysis before and after Treatment with Adalimumab in Patients with Ankylosing Spondylitis Identifies Molecular Pathways Associated with Response to Therapy.

The etiology of Ankylosing spondylitis (AS) is still unknown and the identification of the involved molecular pathogenetic pathways is a current challenge in the study of the disease. Adalimumab (ADA), an anti-tumor necrosis factor (TNF)-alpha agent, is used in the treatment of AS. We aimed at identifying pathogenetic pathways modified by ADA in patients with a good response to the treatment. Gene expression analysis of Peripheral Blood Cells (PBC) from six responders and four not responder patients was performed before and after treatment. Differentially expressed genes (DEGs) were submitted to functional enrichment analysis and network analysis, followed by modules selection. Most of the DEGs were involved in signaling pathways and in immune response. We identified three modules that were mostly impacted by ADA therapy and included genes involved in mitogen activated protein (MAP) kinase, wingless related integration site (Wnt), fibroblast growth factor (FGF) receptor, and Toll-like receptor (TCR) signaling. A separate analysis showed that a higher percentage of DEGs was modified by ADA in responders (44%) compared to non-responders (12%). Moreover, only in the responder group, TNF, Wnt, TLRs and type I interferon signaling were corrected by the treatment. We hypothesize that these pathways are strongly associated to AS pathogenesis and that they might be considered as possible targets of new drugs in the treatment of AS.

Autoimmunity and infection in common variable immunodeficiency (CVID).

Common variable immunodeficiency (CVID) is a heterogeneous group of diseases, characterized by primary hypogammaglobulinemia. B and T cell abnormalities have been described in CVID. Typical clinical features of CVID are recurrent airway infections; lymphoproliferative, autoinflammatory, or neoplastic disorders; and autoimmune diseases among which autoimmune thrombocytopenia (ITP) is the most common. The coexistence of immunodeficiency and autoimmunity appears paradoxical, since one represents a hypoimmune state and the other a hyperimmune state. Considering both innate and adaptive immune response abnormalities in CVID, it is easier to understand the mechanisms that lead to a breakdown of self-tolerance. CD21(low) B cells derive from mature B cells that have undergone chronic immune stimulation; they are increased in CVID patients. The expansion of CD21(low) B cells is also observed in certain autoimmune diseases. We have studied CD21(low) B cells in patients with CVID, CVID, and ITP and with ITP only. We observed a statistically significant increase in the CD21(low) population in the three pathological groups. Moreover, we found statistical differences between the two groups of CVID patients: patients with ITP had a higher percentage of CD21(low) cells. Our data suggest that CD21(low) cells are related to autoimmunity and may represent a link between infection and autoimmunity.

Characterization of CD30/CD30L(+) Cells in Peripheral Blood and Synovial Fluid of Patients with Rheumatoid Arthritis.

The CD30/CD30L signalling system has been implicated in the pathogenesis of several autoimmune and inflammatory conditions. In rheumatoid arthritis (RA), soluble CD30 (sCD30) levels reflect the recruitment of CD30(+) T cells into the inflamed joints and correlate with a positive response to immunosuppressive therapy. The aim of our report was to clarify the role of CD30/CD30L signalling system in the pathogenesis of RA. Our analysis of the CD30L(+) T cell subsets in peripheral blood (PB) and synovial fluid (SF) of RA patients and of the related cytokine profiles suggests the involvement of CD30/CD30L signalling in polarization of T cells towards a Th17 phenotype with proinflammatory features. Moreover, in RA SF nearly 50% of Treg cells express CD30, probably as an attempt to downmodulate the ongoing inflammation. We also show here that the engagement of CD30L on neutrophils stimulated with CD30/Fc chimera may play a crucial role in RA inflammation since activated neutrophils release IL-8, thus potentially amplifying the local inflammatory damage. In conclusion, the results obtained suggest that the complex CD30/CD30L signalling pathway is implicated in the pathogenesis and progression of RA synovitis through a concerted action on several immune effector cells.

Gene Expression Profiling in Peripheral Blood Cells and Synovial Membranes of Patients with Psoriatic Arthritis.

BACKGROUND: Psoriatic arthritis (PsA) is an inflammatory arthritis whose pathogenesis is poorly understood; it is characterized by bone erosions and new bone formation. The diagnosis of PsA is mainly clinical and diagnostic biomarkers are not yet available. The aim of this work was to clarify some aspects of the disease pathogenesis and to identify specific gene signatures in paired peripheral blood cells (PBC) and synovial biopsies of patients with PsA. Moreover, we tried to identify biomarkers that can be used in clinical practice. METHODS: PBC and synovial biopsies of 10 patients with PsA were used to study gene expression using Affymetrix arrays. The expression values were validated by Q-PCR, FACS analysis and by the detection of soluble mediators. RESULTS: Synovial biopsies of patients showed a modulation of approximately 200 genes when compared to the biopsies of healthy donors. Among the differentially expressed genes we observed the upregulation of Th17 related genes and of type I interferon (IFN) inducible genes. FACS analysis confirmed the Th17 polarization. Moreover, the synovial trascriptome shows gene clusters (bone remodeling, angiogenesis and inflammation) involved in the pathogenesis of PsA. Interestingly 90 genes are modulated in both compartments (PBC and synovium) suggesting that signature pathways in PBC mirror those of the inflamed synovium. Finally the osteoactivin gene was upregulared in both PBC and synovial biopsies and this finding was confirmed by the detection of high levels of osteoactivin in PsA sera but not in other inflammatory arthritides. CONCLUSIONS: We describe the first analysis of the trancriptome in paired synovial tissue and PBC of patients with PsA. This study strengthens the hypothesis that PsA is of autoimmune origin since the coactivity of IFN and Th17 pathways is typical of autoimmunity. Finally these findings have allowed the identification of a possible disease biomarker, osteoactivin, easily detectable in PsA serum.

Crossreactive autoantibodies directed against cutaneous and joint antigens are present in psoriatic arthritis.

BACKGROUND: Psoriatic arthritis (PsA) is a chronic inflammatory disease of unknown origin, characterized by erosions and new bone formation. Diagnosis of PsA is mainly clinical and there are no biomarkers available. Moreover in PsA autoantibodies have not been described so far. Indeed an autoimmune origin has been suggested but never proven. Aim of the study was to investigate the possible presence of autoantibodies typically associated with PsA. METHODS: We used pooled IgG immunoglobulins derived from 30 patients with PsA to screen a random peptide library in order to identify disease relevant autoantigen peptides. RESULTS: Among the selected peptides, one was recognised by nearly all the patients' sera. The identified peptide (PsA peptide: TNRRGRGSPGAL) shows sequence similarities with skin autoantigens, such as fibrillin 3, a constituent of actin microfibrils, desmocollin 3, a constituent of the desmosomes and keratin 78, a component of epithelial cytoskeleton. Interestingly the PsA peptide shares homology with the nebulin-related anchoring protein (N-RAP), a protein localized in the enthesis (point of insertion of a tendon or ligament to the bone), which represents the first affected site during early PsA. Antibodies affinity purified against the PsA peptide recognize fibrillin, desmocollin, keratin and N-RAP. Moreover antibodies directed against the PsA peptide are detectable in 85% of PsA patients. Such antibodies are not present in healthy donors and are present in 13/100 patients with seroposive rheumatoid arthritis (RA). In seronegative RA these antibodies are detectable only in 3/100 patients. CONCLUSIONS: Our results indicate that PsA is characterized by the presence of serum autoantibodies crossreacting with an epitope shared by skin and joint antigens.

Gene expression profiling in peripheral blood mononuclear cells of patients with common variable immunodeficiency: modulation of adaptive immune response following intravenous immunoglobulin therapy.

BACKGROUND: Regular intravenous immunoglobulin treatment is used to replace antibody deficiency in primary immunodeficiency diseases; however the therapeutic effect seems to be related not only to antibody replacement but also to an active role in the modulation of the immune response. Common variable immunodeficiency is the most frequent primary immunodeficiency seen in clinical practice. METHODS: We have studied the effect of intravenous immunoglobulin replacement in patients with common variable immunodeficiency by evaluating the gene-expression profiles from Affimetrix HG-U133A. Some of the gene array results were validated by real time RT-PCR and by the measurement of circulating cytokines and chemokines by ELISA. Moreover we performed FACS analysis of blood mononuclear cells from the patients enrolled in the study. RESULTS: A series of genes involved in innate and acquired immune responses were markedly up- or down-modulated before therapy. Such genes included CD14, CD36, LEPR, IRF-5, RGS-1, CD38, TNFRSF25, IL-4, CXCR4, CCR3, IL-8. Most of these modulated genes showed an expression similar to that of normal controls after immunoglobulin replacement. Real time RT-PCR of selected genes and serum levels of IL-4, CXCR4 before and after therapy changed accordingly to gene array results. Interestingly, serum levels of IL-8 remained unchanged, as the corresponding gene, before and after treatment. FACS analysis showed a marked decrease of CD8+T cells and an increase of CD4+T cells following treatment. Moreover we observed a marked increase of CD23⁻CD27⁻IgM⁻IgG⁻ B cells (centrocytes). CONCLUSIONS: Our results are in accordance with previous reports and provide further support to the hypothesis that the benefits of intravenous immunoglobulin therapy are not only related to antibody replacement but also to its ability to modulate the immune response in common variable immunodeficiency.

In rheumatoid arthritis soluble CD30 ligand is present at high levels and induces apoptosis of CD30(+)T cells.

CD30 and CD30 ligand (CD30L) are members of TNF-receptor and TNF superfamilies respectively. CD30(+)T cells are increased in several diseases and interaction between CD30(+) and CD30L(+)T cells leads either to cell proliferation or apoptosis. In patients with rheumatoid arthritis (RA), soluble CD30 (sCD30) levels seem to reflect the recruitment of CD30(+)T cells into the inflamed joints and are predictive of a positive response to classical and biological immunosuppressive therapy. We have evaluated the presence of soluble CD30L (sCD30L) in the sera and synovial fluid of patients with RA and defined whether it binds surface CD30 molecule and is functionally active. We found high levels of sCD30L in sera and synovial fluid of RA patients; the molecule is shedded upon direct contact of CD30(+)/CD30L(+)T cells. Moreover sCD30L binds surface CD30 constitutively expressed by Jurkat cell line. Finally recombinant sCD30L and sera from patients with high levels of sCD30L are able to inhibit CD30(+)T cell proliferation by inducing cell apoptosis. Our findings suggest that circulant sCD30L is functionally active and that it may favor persistence of active inflammation by inducing apoptosis of CD30(+)T cells, known to down-modulate inflammation in rheumatoid synovitis.

Leprosy initially misdiagnosed as sarcoidosis, adult-onset still disease, or autoinflammatory disease.

Leprosy is a chronic granulomatous disease caused by Mycobacterium leprae. We describe the case of a 20-year-old man from India living in Italy since 2003, who presented with erythematous papules and nodules distributed on his arms, legs, and face in 2006. He also had episodes of high fever, polyarthritis, and episcleritis. Sarcoidosis was suspected on the basis of elevated angiotensin-converting enzyme and bronchoalveolar lavage fluid, and the patient was treated with corticosteroids for about a year. A flare of the disease occurred each time corticosteroid was tapered or suspended. An autoinflammatory disease was then suspected and treated with immunosuppressant. Only the third deep skin biopsy revealed the presence of M. leprae. The lack of clinical suspicion and the unfamiliarity with the histology of leprosy delayed diagnosis and treatment. Leprosy should be considered in the differential diagnoses of patients presenting with rheumatic and cutaneous manifestations especially when they come from countries where the disease is endemic.

Schnitzler syndrome, an autoimmune-autoinflammatory syndrome: report of two new cases and review of the literature.

Schnitzler syndrome is a rare disorder characterized clinically by chronic urticarial rash accompanied by fever, arthralgia or arthritis, bone pain and lymphoadenopathy and biochemically by monoclonal gammopathy and elevation of inflammatory indices. The disorder is very likely under-recognized and its origin remains obscure although it may be included among the immune mediated inflammatory diseases with features of autoinflammation and autoimmunity. We describe here two patients affected by Schnitzler syndrome, both refractory to corticosteroids and immunosuppressive therapy, successfully treated with the interleukin-1 receptor antagonist Anakinra. Unfortunately after two weeks, one patient experienced an important local adverse reaction to the biological drug. We decided to discontinue Anakinra with flare of the disease after 24 h. We therefore switched to Rituximab obtaining a complete remission in two months. We searched MEDLINE in order to analyze the frequency of the disease, its pathogenesis and outcome. The electronic search was conducted using the following key words "Schnitzler syndrome" and "Treatment of Schnitzler syndrome". All the selected papers, except the clinical reviews, described at least one case of Schnitzler syndrome. The review of the literature highlighted that Schnitzler syndrome remains an enigmatic disorder hard to categorize and to treat.

A score of risk factors associated with ischemic digital ulcers in patients affected by systemic sclerosis treated with iloprost.

A single series of patients affected by systemic sclerosis (SSc) and cyclically treated with iloprost was reviewed in order to evaluate the incidence of digital ulcers (DUs) and to compare the characteristics between the patients with and without this painful and disabling vascular complication. The record charts of 85 SSc patients were revised. Ischemic DUs and scleroderma contracture ulcers were separately considered. Twenty-nine subjects developed ischemic DUs during the course of the disease; whereas, scleroderma contracture ulcers occurred in six subjects. Ischemic DUs were associated with younger age at scleroderma onset, a longer disease duration, a longer time delay from scleroderma diagnosis to iloprost therapy, a bigger skin involvement, the presence of joint contractures, a videocapillaroscopic late pattern, a history of smoking, and of corticosteroids therapy. After the exclusion of four subjects with concomitant peripheral arterial disease, a forward-stepwise logistic regression analysis showed that only four variables, i.e., age at scleroderma onset, delay in beginning iloprost therapy, history of smoking, and presence of joint contractures remained significantly associated with ischemic DUs. In a score reflecting the sum of these four risk factors, the prevalence of ischemic DUs increased progressively from the lowest to the highest value of the score. The predictivity of this model was evaluated by the receiver-operating characteristics curve, with an estimated area under the curve of 0.836 with 95% confidence interval from 0.736 to 0.937. All the patients with scleroderma contracture ulcers were characterized by both diffuse pattern of disease and positivity for anti-Scl70 antibody. In this retrospective study, scleroderma patients with ischemic DUs are characterized by early disease onset, delay in beginning iloprost therapy, smoking habit, and presence of joint contraction. A score reflecting the sum of these factors may be useful to predict the risk of developing ischemic DUs.

[Homocysteine and rheumatic disease]. / Omocisteina e malattie reumatiche.

In the last decade hyperhomocysteinemia has become an element of great interest as a recognized factor of independent risk for atherotrombosis. Moreover a role has been suggested in some different diseases, like rheumatic ones. Hyperhomocysteinemia could represent a mechanism of amplification of vascular damage in rheumatic disease, therefore it could interact with treatements. Moreover it could contribute to explain the high incidence of cardiovascular events, than they do not find support in traditional risk factors.