SciCombinator

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Concept: Lupus erythematosus

198

Signals controlling the generation of regulatory B (Breg) cells remain ill-defined. Here we report an “auto”-regulatory feedback mechanism between plasmacytoid dendritic cells (pDCs) and Breg cells. In healthy individuals, pDCs drive the differentiation of CD19(+)CD24(hi)CD38(hi) (immature) B cells into IL-10-producing CD24(+)CD38(hi) Breg cells and plasmablasts, via the release of IFN-α and CD40 engagement. CD24(+)CD38(hi) Breg cells conversely restrained IFN-α production by pDCs via IL-10 release. In systemic lupus erythematosus (SLE), this cross-talk was compromised; pDCs promoted plasmablast differentiation but failed to induce Breg cells. This defect was recapitulated in healthy B cells upon exposure to a high concentration of IFN-α. Defective pDC-mediated expansion of CD24(+)CD38(hi) Breg cell numbers in SLE was associated with altered STAT1 and STAT3 activation. Both altered pDC-CD24(+)CD38(hi) Breg cell interactions and STAT1-STAT3 activation were normalized in SLE patients responding to rituximab. We propose that alteration in pDC-CD24(+)CD38(hi) Breg cell interaction contributes to the pathogenesis of SLE.

Concepts: Cell nucleus, Rheumatoid arthritis, Systemic lupus erythematosus, Lupus erythematosus

176

Genetic diversity across different human populations can enhance understanding of the genetic basis of disease. We calculated the genetic risk of 102 diseases in 1,043 unrelated individuals across 51 populations of the Human Genome Diversity Panel. We found that genetic risk for type 2 diabetes and pancreatic cancer decreased as humans migrated toward East Asia. In addition, biliary liver cirrhosis, alopecia areata, bladder cancer, inflammatory bowel disease, membranous nephropathy, systemic lupus erythematosus, systemic sclerosis, ulcerative colitis, and vitiligo have undergone genetic risk differentiation. This analysis represents a large-scale attempt to characterize genetic risk differentiation in the context of migration. We anticipate that our findings will enable detailed analysis pertaining to the driving forces behind genetic risk differentiation.

Concepts: Human Genome Project, Rheumatology, Ulcerative colitis, Corticosteroid, Systemic lupus erythematosus, Lupus erythematosus, Autoimmune diseases, Proteinuria

173

Systemic sclerosis (scleroderma) is unique among the rheumatic diseases because it presents the challenge of managing a chronic multisystem autoimmune disease with a widespread obliterative vasculopathy of small arteries that is associated with varying degrees of tissue fibrosis. The hallmark of scleroderma is clinical heterogeneity with subsets that vary in the degree of disease expression, organ involvement, and ultimate prognosis. Thus, the term scleroderma is used to describe patients who have common manifestations that link them together, whereas a highly variable clinical course exists that spans from mild and subtle findings to aggressive, life-threatening multisystem disease. The physician needs to carefully characterize each patient to understand the specific manifestations and level of disease activity to decide appropriate treatment. This is particularly important in treating a patient with scleroderma because there is no treatment that has been proven to modify the overall disease course, although therapy that targets specific organ involvement early before irreversible damage occurs improves both quality of life and survival. This review describes our approach as defined by evidence, expert opinion, and our experience treating patients. Scleroderma is a multisystem disease with variable expression; thus, any treatment plan must be holistic, yet at the same time focus on the dominant organ disease. The goal of therapy is to improve quality of life by minimizing specific organ involvement and subsequent life-threatening disease. At the same time the many factors that alter daily function need to be addressed, including nutrition, pain, deconditioning, musculoskeletal disuse, comorbid conditions, and the emotional aspects of the disease, such as fear, depression, and the social withdrawal caused by disfigurement.

Concepts: Medicine, Diseases and disorders, Rheumatology, Autoimmune disease, Lupus erythematosus, Systemic disease, Scleroderma, Systemic scleroderma

166

We previously reported that the G allele of rs3853839 at 3'untranslated region (UTR) of Toll-like receptor 7 () was associated with elevated transcript expression and increased risk for systemic lupus erythematosus (SLE) in 9,274 Eastern Asians [ = 6.5×10, odds ratio (OR) (95%CI) = 1.27 (1.17-1.36)]. Here, we conducted trans-ancestral fine-mapping in 13,339 subjects including European Americans, African Americans, and Amerindian/Hispanics and confirmed rs3853839 as the only variant within the region exhibiting consistent and independent association with SLE (  = 7.5×10, OR = 1.24 [1.18-1.34]). The risk G allele was associated with significantly increased levels of mRNA and protein in peripheral blood mononuclear cells (PBMCs) and elevated luciferase activity of reporter gene in transfected cells. 3'UTR sequence bearing the non-risk C allele of rs3853839 matches a predicted binding site of microRNA-3148 (miR-3148), suggesting that this microRNA may regulate expression. Indeed, miR-3148 levels were inversely correlated with transcript levels in PBMCs from SLE patients and controls (R = 0.255,  = 0.001). Overexpression of miR-3148 in HEK-293 cells led to significant dose-dependent decrease in luciferase activity for construct driven by 3'UTR segment bearing the C allele ( = 0.0003). Compared with the G-allele construct, the C-allele construct showed greater than two-fold reduction of luciferase activity in the presence of miR-3148. Reduced modulation by miR-3148 conferred slower degradation of the risk G-allele containing transcripts, resulting in elevated levels of gene products. These data establish rs3853839 of as a shared risk variant of SLE in 22,613 subjects of Asian, EA, AA, and Amerindian/Hispanic ancestries (  = 2.0×10, OR = 1.25 [1.20-1.32]), which confers allelic effect on transcript turnover via differential binding to the epigenetic factor miR-3148.

Concepts: Protein, Gene, Genetics, Cell nucleus, Gene expression, Systemic lupus erythematosus, Lupus erythematosus

156

Pilot studies have estimated cancer incidence in patients with systemic lupus erythematous (SLE). However, the results have been inconclusive. To ascertain the correlation between SLE and malignancy more comprehensively and precisely, we conducted a meta-analysis.

Concepts: Systemic lupus erythematosus, Lupus erythematosus

146

Systemic lupus erythematosus (SLE) patients exhibit immense heterogeneity which is challenging from the diagnostic perspective. Emerging high throughput sequencing technologies have been proved to be a useful platform to understand the complex and dynamic disease processes. SLE patients categorised based on autoantibody specificities are reported to have differential immuno-regulatory mechanisms. Therefore, we performed RNA-seq analysis to identify transcriptomics of SLE patients with distinguished autoantibody specificities. The SLE patients were segregated into three subsets based on the type of autoantibodies present in their sera (anti-dsDNA+ group with anti-dsDNA autoantibody alone; anti-ENA+ group having autoantibodies against extractable nuclear antigens (ENA) only, and anti-dsDNA+ENA+ group having autoantibodies to both dsDNA and ENA). Global transcriptome profiling for each SLE patients subsets was performed using Illumina® Hiseq-2000 platform. The biological relevance of dysregulated transcripts in each SLE subsets was assessed by ingenuity pathway analysis (IPA) software. We observed that dysregulation in the transcriptome expression pattern was clearly distinct in each SLE patients subsets. IPA analysis of transcripts uniquely expressed in different SLE groups revealed specific biological pathways to be affected in each SLE subsets. Multiple cytokine signaling pathways were specifically dysregulated in anti-dsDNA+ patients whereas Interferon signaling was predominantly dysregulated in anti-ENA+ patients. In anti-dsDNA+ENA+ patients regulation of actin based motility by Rho pathway was significantly affected. The granulocyte gene signature was a common feature to all SLE subsets; however, anti-dsDNA+ group showed relatively predominant expression of these genes. Dysregulation of Plasma cell related transcripts were higher in anti-dsDNA+ and anti-ENA+ patients as compared to anti-dsDNA+ ENA+. Association of specific canonical pathways with the uniquely expressed transcripts in each SLE subgroup indicates that specific immunological disease mechanisms are operative in distinct SLE patients' subsets. This ‘sub-grouping’ approach could further be useful for clinical evaluation of SLE patients and devising targeted therapeutics.

Concepts: Rheumatoid arthritis, Systemic lupus erythematosus, Lupus erythematosus

144

Over the last few years, dermoscopy has been shown to be a useful tool in assisting the noninvasive diagnosis of various general dermatological disorders. In this article, we sought to provide an up-to-date practical overview on the use of dermoscopy in general dermatology by analysing the dermoscopic differential diagnosis of relatively common dermatological disorders grouped according to their clinical presentation, i.e. dermatoses presenting with erythematous-desquamative patches/plaques (plaque psoriasis, eczematous dermatitis, pityriasis rosea, mycosis fungoides and subacute cutaneous lupus erythematosus), papulosquamous/papulokeratotic dermatoses (lichen planus, pityriasis rosea, papulosquamous sarcoidosis, guttate psoriasis, pityriasis lichenoides chronica, classical pityriasis rubra pilaris, porokeratosis, lymphomatoid papulosis, papulosquamous chronic GVHD, parakeratosis variegata, Grover disease, Darier disease and BRAF-inhibitor-induced acantholytic dyskeratosis), facial inflammatory skin diseases (rosacea, seborrheic dermatitis, discoid lupus erythematosus, sarcoidosis, cutaneous leishmaniasis, lupus vulgaris, granuloma faciale and demodicidosis), acquired keratodermas (chronic hand eczema, palmar psoriasis, keratoderma due to mycosis fungoides, keratoderma resulting from pityriasis rubra pilaris, tinea manuum, palmar lichen planus and aquagenic palmar keratoderma), sclero-atrophic dermatoses (necrobiosis lipoidica, morphea and cutaneous lichen sclerosus), hypopigmented macular diseases (extragenital guttate lichen sclerosus, achromic pityriasis versicolor, guttate vitiligo, idiopathic guttate hypomelanosis, progressive macular hypomelanosis and postinflammatory hypopigmentations), hyperpigmented maculopapular diseases (pityriasis versicolor, lichen planus pigmentosus, Gougerot-Carteaud syndrome, Dowling-Degos disease, erythema ab igne, macular amyloidosis, lichen amyloidosus, friction melanosis, terra firma-forme dermatosis, urticaria pigmentosa and telangiectasia macularis eruptiva perstans), itchy papulonodular dermatoses (hypertrophic lichen planus, prurigo nodularis, nodular scabies and acquired perforating dermatosis), erythrodermas (due to psoriasis, atopic dermatitis, mycosis fungoides, pityriasis rubra pilaris and scabies), noninfectious balanitis (Zoon’s plasma cell balanitis, psoriatic balanitis, seborrheic dermatitis and non-specific balanitis) and erythroplasia of Queyrat, inflammatory cicatricial alopecias (scalp discoid lupus erythematosus, lichen planopilaris, frontal fibrosing alopecia and folliculitis decalvans), nonscarring alopecias (alopecia areata, trichotillomania, androgenetic alopecia and telogen effluvium) and scaling disorders of the scalp (tinea capitis, scalp psoriasis, seborrheic dermatitis and pityriasis amiantacea).

Concepts: Systemic lupus erythematosus, Lupus erythematosus, Autoimmune diseases, Immunosuppressive drug, Eczema, Psoriasis, Conditions of the skin appendages, Discoid lupus erythematosus

139

Cyclic GMP-AMP synthase (cGAS) initiates the innate immune system in response to cytosolic dsDNA. After binding and activation from dsDNA, cGAS uses ATP and GTP to synthesize 2', 3' -cGAMP (cGAMP), a cyclic dinucleotide second messenger with mixed 2'-5' and 3'-5' phosphodiester bonds. Inappropriate stimulation of cGAS has been implicated in autoimmune disease such as systemic lupus erythematosus, thus inhibition of cGAS may be of therapeutic benefit in some diseases; however, the size and polarity of the cGAS active site makes it a challenging target for the development of conventional substrate-competitive inhibitors. We report here the development of a high affinity (KD = 200 nM) inhibitor from a low affinity fragment hit with supporting biochemical and structural data showing these molecules bind to the cGAS active site. We also report a new high throughput cGAS fluorescence polarization (FP)-based assay to enable the rapid identification and optimization of cGAS inhibitors. This FP assay uses Cy5-labelled cGAMP in combination with a novel high affinity monoclonal antibody that specifically recognizes cGAMP with no cross reactivity to cAMP, cGMP, ATP, or GTP. Given its role in the innate immune response, cGAS is a promising therapeutic target for autoinflammatory disease. Our results demonstrate its druggability, provide a high affinity tool compound, and establish a high throughput assay for the identification of next generation cGAS inhibitors.

Concepts: Immune system, Innate immune system, Rheumatoid arthritis, Rheumatology, Immunity, Systemic lupus erythematosus, Lupus erythematosus, Immunosuppressive drug

137

Acute transverse myelitis (ATM) is a severe complication of systemic lupus erythematosus (SLE). This study evaluated the clinical factors related to outcome in patients with SLE-associated ATM.

Concepts: Systemic lupus erythematosus, Lupus erythematosus, Autoimmune diseases

101

Systemic lupus erythematosus (SLE) is an autoimmune disease, which results in various organ pathologies. However, current treatment towards SLE is suboptimal. Erythropoietin (EPO) has been shown to promote SLE recovery, but clinical application can be limited by its haematopoiesis-stimulating effects. EPO-derived helix-B peptide (ARA290) is non-erythrogenic but has been reported to retain the anti-inflammatory and tissue-protective functions of EPO. Therefore, here we investigated the effects and potential mechanisms of ARA290 on SLE. The administration of ARA290 to pristane-induced SLE and MRL/lpr mice significantly suppressed the level of serum antinuclear autoantibodies (ANAs) and anti-dsDNA autoantibodies, reduced the deposition of IgG and C3, and ameliorated the nephritis symptoms. Moreover, the serum concentrations of inflammatory cytokine IL-6, MCP-1 and TNF-α in SLE mice were reduced by ARA290. Further, ARA290 decreased the number of apoptotic cells in kidney. In vitro experiment revealed that ARA290 inhibited the inflammatory activation of macrophages and promoted the phagocytotic function of macrophages to apoptotic cells. Finally, ARA290 did not induce haematopoiesis during treatment. In conclusion, ARA290 ameliorated SLE, which at least could be partly due to its anti-inflammatory and apoptotic cell clearance promoting effects, without stimulating haematopoiesis, suggesting that ARA290 could be a hopeful candidate for SLE treatment.

Concepts: Immune system, Rheumatoid arthritis, Systemic lupus erythematosus, Lupus erythematosus, Glomerulonephritis