The role of cytokines in the pathogenesis of cutaneous lupus erythematosus

Expression of lymphocyte activation gene-3 on CD4+T cells is regulated by cytokine interleukin-18 in myasthenia gravis

Myasthenia gravis (MG) is a T cell-dependent, B cell-mediated, and complement-dependent autoimmune disease. Lymphocyte activation gene-3 (LAG-3; CD223) is an immune checkpoint protein that plays an important role in maintaining autoimmune tolerance and homeostasis. To investigate the cytokine-regulated expression pattern of LAG-3, CD4+T cells were sorted from the peripheral blood of healthy volunteers by density gradient centrifugation and stimulated with various cytokines in vitro. The expression of membrane LAG-3 (mLAG-3), membrane a disintegrin and metallopeptidase domain10 (mADAM10) and membrane ADAM17 (mADAM17) on CD4+T cells was detected by flow cytometry; the concentration of soluble LAG-3 (sLAG-3) was detected by ELISA; and the relative expression of genes at the transcriptional level was detected by fluorescence quantitative RT-PCR (qRT-PCR). sLAG-3 levels were significantly increased in the peripheral plasma of AChR Ab-positive patients with MG compared to healthy volunteers, while the percentage of mLAG-3 expression on CD4+T lymphocytes in the peripheral blood of patients with MG was significantly reduced. IL-18 inhibited mLAG-3 levels on CD4+T cells in a concentration-dependent manner. Additionally, the concentration of sLAG-3 in the supernatant increased. After PHA and IL-18 stimulation, ADAM10 and ADAM17 also increased compared to those in the PHA-active group. Moreover, there were significant differences in the expression of mADAM10 and mADAM17 in CD4+T lymphocytes between patients with MG and healthy volunteers. These results suggest that IL-18 may regulate the expression pattern of mLAG-3 in CD4+T cells and sLAG-3 via ADAM10- and ADAM17-mediated pathways, thus affecting the immune effects of CD4+T cells. This study provides a preliminary exploration of the upstream regulatory molecules of the LAG-3 and IL-18/LAG-3 signalling pathways for potential targeted therapy of autoimmune diseases in the future.

Expression network analysis of bovine skin infested with Rhipicephalus australis identifies pro-inflammatory genes contributing to tick susceptibility

The skin is the primary feeding site of ticks that infest livestock animals such as cattle. The highly specialised functions of skin at the molecular level may be a factor contributing to variation in susceptibility to tick infestation; but these remain to be well defined. The aim of this study was to investigate the bovine skin transcriptomic profiles of tick-naïve and tick-infested cattle and to uncover the gene expression networks that influence contrasting phenotypes of host resistance to ticks. RNA-Seq data was obtained from skin of Brangus cattle with high (n = 5) and low (n = 6) host resistance at 0 and 12 weeks following artificial tick challenge with Rhipicephalus australis larvae. No differentially expressed genes were detected pre-infestation between high and low resistance groups, but at 12-weeks there were 229 differentially expressed genes (DEGs; FDR < 0.05), of which 212 were the target of at least 1866 transcription factors (TFs) expressed in skin. Regulatory impact factor (RIF) analysis identified 158 significant TFs (P < 0.05) of which GRHL3, and DTX1 were also DEGs in the experiment. Gene term enrichment showed the significant TFs and DEGs were enriched in processes related to immune response and biological pathways related to host response to infectious diseases. Interferon Type 1-stimulated genes, including MX2, ISG15, MX1, OAS2 were upregulated in low host resistance steers after repeated tick challenge, suggesting dysregulated wound healing and chronic inflammatory skin processes contributing to host susceptibility to ticks. The present study provides an assessment of the bovine skin transcriptome before and after repeated tick challenge and shows that the up-regulation of pro-inflammatory genes is a prominent feature in the skin of tick-susceptible animals. In addition, the identification of transcription factors with high regulatory impact provides insights into the potentially meaningful gene-gene interactions involved in the variation of phenotypes of bovine host resistance to ticks.

Potential clinical implications of molecular mimicry-induced autoimmunity

BACKGROUND

Molecular mimicry is hypothesized to be a mechanism by which autoimmune diseases are triggered. It refers to sequence or structural homology between foreign antigens and self-antigens, which can activate cross-reactive lymphocytes that attack host tissues. Elucidating the role of molecular mimicry in human autoimmunity could have important clinical implications.

OBJECTIVE

To review evidence for the role of molecular mimicry in major autoimmune diseases and discuss potential clinical implications.

METHODS

Comprehensive literature review of clinical trials, observational studies, animal models, and immunology studies on molecular mimicry in multiple sclerosis, type 1 diabetes, rheumatoid arthritis, lupus, Guillain-Barre syndrome, autoimmune myocarditis, and primary biliary cirrhosis published from 2000-2023.

RESULTS

Substantial indirect evidence supports molecular mimicry as a contributor to loss of self-tolerance in several autoimmune conditions. Proposed microbial triggers include Epstein-Barr virus, coxsackievirus, Campylobacter jejuni, and bacterial commensals. Key mechanisms involve cross-reactive T cells and autoantibodies induced by epitope homology between microbial and self-antigens. Perpetuation of autoimmunity involves epitope spreading, inflammatory mediators, and genetic factors.

CONCLUSIONS

Molecular mimicry plausibly explains initial stages of autoimmune pathogenesis induced by infection or microbiota disturbances. Understanding mimicry antigens and pathways could enable improved prediction, monitoring, and antigen-specific immunotherapy for autoimmune disorders. However, definitive proof of causation in humans remains limited. Further research should focus on establishing clinical evidence and utility.

Spatial characterization of interface dermatitis in cutaneous lupus reveals novel chemokine ligand-receptor pairs that drive disease

Chemokines play critical roles in the recruitment and activation of immune cells in both homeostatic and pathologic conditions. Here, we examined chemokine ligand-receptor pairs to better understand the immunopathogenesis of cutaneous lupus erythematosus (CLE), a complex autoimmune connective tissue disorder. We used suction blister biopsies to measure cellular infiltrates with spectral flow cytometry in the interface dermatitis reaction, as well as 184 protein analytes in interstitial skin fluid using Olink targeted proteomics. Flow and Olink data concordantly demonstrated significant increases in T cells and antigen presenting cells (APCs). We also performed spatial transcriptomics and spatial proteomics of punch biopsies using digital spatial profiling (DSP) technology on CLE skin and healthy margin controls to examine discreet locations within the tissue. Spatial and Olink data confirmed elevation of interferon (IFN) and IFN-inducible CXCR3 chemokine ligands. Comparing involved versus uninvolved keratinocytes in CLE samples revealed upregulation of essential inflammatory response genes in areas near interface dermatitis, including AIM2. Our Olink data confirmed upregulation of Caspase 8, IL-18 which is the final product of AIM2 activation, and induced chemokines including CCL8 and CXCL6 in CLE lesional samples. Chemotaxis assays using PBMCs from healthy and CLE donors revealed that T cells are equally poised to respond to CXCR3 ligands, whereas CD14+CD16+ APC populations are more sensitive to CXCL6 via CXCR1 and CD14+ are more sensitive to CCL8 via CCR2. Taken together, our data map a pathway from keratinocyte injury to lymphocyte recruitment in CLE via AIM2-Casp8-IL-18-CXCL6/CXCR1 and CCL8/CCR2, and IFNG/IFNL1-CXCL9/CXCL11-CXCR3.

The effects of Lactobacillus delbrueckii and Lactobacillus rhamnosus on cytokines and their related molecules: An ex vivo study on patients with systemic lupus erythematosus

Objectives

This study aimed to assess the ex vivo impact of Lactobacillus delbrueckii (L. delbrueckii) and Lactobacillus rhamnosus (L. rhamnosus) on inflammatory and anti-inflammatory cytokines as well as their related molecules on the peripheral blood mononuclear cells (PBMCs) of systemic lupus erythematosus (SLE) patients.

Patients and methods

This study was conducted with 20 newly diagnosed SLE patients (18 females, 2 males; mean age: 33.3±12.4 years; range, 18 to 68 years) between September 2017 and September 2018. Extracted PBMCs from each patient were divided into 4 cell groups in our study. Three cell groups act as treatment groups receiving L. rhamnosus (107 CFU/mL), L. delbrueckii (105 CFU/mL) or a mixture of both, and one group act as our untreated control group in the absence of any probiotic agents. All cell groups were cultured in RPMI 1460 medium for 48 h. Then, total RNA was extracted, and cDNA was synthesized.

Results

The gene expression levels of forkhead box P3 (FOXP3), transforming growth factor beta (TGF-β), interleukin (IL)-6, IL-10, and IL-2 were evaluated by a quantitative real-time polymerase chain reaction. The results revealed that expression levels of FOXP3, TGF-β, IL-10, and IL-2 increased and the level of IL-6 decreased in probiotics-receiving groups compared to the control group. Lactobacillus delbrueckii and L. rhamnosus enhanced the expression of regulatory T cell-related molecules such as FOXP3 and IL-2 and also increased the expression of IL-10. These probiotics also reduced the expression of IL-6 as proinflammatory cytokines in the PBMCs of SLE patients.

Conclusion

The results of the present study show that these probiotics could be effective in regulating the balance of cytokine gene expression ex vivo , and due to their beneficial effects, they can be an intriguing option in the production of new complement drugs for SLE.

Regulation of Photosensitivity by the Hippo Pathway in Lupus Skin

OBJECTIVE

Photosensitivity is one of the most common manifestations of systemic lupus erythematosus (SLE), yet its pathogenesis is not well understood. The normal-appearing epidermis of patients with SLE exhibits increased ultraviolet B (UVB)-driven cell death that persists in cell culture. Here, we investigated the role of epigenetic modification and Hippo signaling in enhanced UVB-induced apoptosis seen in SLE keratinocytes.

METHODS

We analyzed DNA methylation in cultured keratinocytes from SLE patients compared to keratinocytes from healthy controls (n = 6/group). Protein expression was validated in cultured keratinocytes using immunoblotting and immunofluorescence. An immortalized keratinocyte line overexpressing WWC1 was generated via lentiviral vector. WWC1-driven changes were inhibited using a large tumor suppressor kinase 1/2 (LATS1/2) inhibitor (TRULI) and small interfering RNA (siRNA). The interaction between the Yes-associated protein (YAP) and the transcriptional enhancer associate domain (TEAD) was inhibited by overexpression of an N/TERT cell line expressing a tetracycline-inducible green fluorescent protein-tagged protein that inhibits YAP-TEAD binding (TEADi). Apoptosis was assessed using cleaved caspase 3/7 and TUNEL staining.

RESULTS

Hippo signaling was the top differentially methylated pathway in SLE versus control keratinocytes. SLE keratinocytes (n = 6) showed significant hypomethylation (Δβ = -0.153) and thus overexpression of the Hippo regulator WWC1 (P = 0.002). WWC1 overexpression increased LATS1/2 kinase activation, leading to YAP cytoplasmic retention and altered proapoptotic transcription in SLE keratinocytes. Accordingly, UVB-mediated apoptosis in keratinocytes could be enhanced by WWC1 overexpression or YAP-TEAD inhibition, mimicking SLE keratinocytes. Importantly, inhibition of LATS1/2 with either the chemical inhibitor TRULI or siRNA effectively eliminated enhanced UVB-apoptosis in SLE keratinocytes.

CONCLUSION

Our work unravels a novel driver of photosensitivity in SLE: overactive Hippo signaling in SLE keratinocytes restricts YAP transcriptional activity, leading to shifts that promote UVB apoptosis.

Cutaneous immune-related adverse events to immune checkpoint inhibitors: from underlying immunological mechanisms to multi-omics prediction

The development of immune checkpoint inhibitors (ICIs) has dramatically altered the landscape of therapy for multiple malignancies, including urothelial carcinoma, non-small cell lung cancer, melanoma and gastric cancer. As part of their anti-tumor properties, ICIs can enhance susceptibility to inflammatory side effects known as immune-related adverse events (irAEs), in which the skin is one of the most commonly and rapidly affected organs. Although numerous questions still remain unanswered, multi-omics technologies have shed light into immunological mechanisms, as well as the correlation between ICI-induced activation of immune systems and the incidence of cirAE (cutaneous irAEs). Therefore, we reviewed integrated biological layers of omics studies combined with clinical data for the prediction biomarkers of cirAEs based on skin pathogenesis. Here, we provide an overview of a spectrum of dermatological irAEs, discuss the pathogenesis of this "off-tumor toxicity" during ICI treatment, and summarize recently investigated biomarkers that may have predictive value for cirAEs via multi-omics approach. Finally, we demonstrate the prognostic significance of cirAEs for immune checkpoint blockades.

Psychiatric symptomatology in skin-restricted lupus patients without axis I psychiatric disorders: A post-hoc analysis

BACKGROUND

Skin-restricted lupus is a chronic inflammatory disease associated with high rates of depression and anxiety disorders. Patients without psychiatric disorders can experience anxiety and depressive symptoms at a subclinical level, which could be risk factors for progression towards psychiatric disorders. It was decided, therefore, to investigate the presence of specific symptoms in skin-restricted lupus patients without axis I psychiatric disorders and their impact on the occurrence of axis I psychiatric disorders during the study follow-up.

METHODS

Longitudinal data of 38 patients and 76 matched controls without active axis I psychiatric disorders from the LuPsy cohort were used. Depressive, neurovegetative, psychic and somatic anxiety symptom scores were established from the Montgomery-Asberg Depression Rating Scale (MADRS) and the Hamilton Anxiety Rating scale (HAMA).

RESULTS

None of the participants had any current active axis I psychiatric disorders but the patients had personality disorders more frequently and had received more past psychotropic treatments than the controls. They also had higher MADRS and HAMA scores than the controls, in particular neurovegetative, psychic anxiety and somatic symptoms scores. No dermatological factor tested was associated with these scores, whereas being a lupus patient was associated with higher neurovegetative and somatic symptoms scores, having a current personality disorder with higher depressive and neurovegetative scores and receiving more past psychotropic treatments with psychic anxiety and somatic symptoms scores. The occurrence of psychiatric disorders during the study follow-up was associated with an elevated psychic anxiety score at baseline and past psychotropic treatment but not with history of psychiatric disorder.

LIMITATIONS

The LuPsy cohort included a large number of patients with axis I psychiatric disorders, the sample without axis I psychiatric disorders is therefore limited.

CONCLUSIONS

We observed numerous psychiatric symptoms among the skin-restricted lupus patients. They should therefore receive special attention in the management of their subclinical symptoms before they progress towards full psychiatric disorders.

Circulating and skin biopsy-present cytokines related to the pathogenesis of cutaneous lupus erythematosus

Cutaneous lupus erythematosus (CLE) is a common disease that may appear as a separate entity from systemic lupus erythematosus (SLE), precede SLE development, or occur as a manifestation of this systemic disease. It has a complex pathophysiology that involves genetic, environmental, and immune-mediated factors creating a self-amplification pro-inflammatory cycle. CLE is characterized by prominent type I interferons (IFNs) inflammation which are considered as the first precursors of the inflammatory cascade generated within the pathophysiology of CLE. TNF-α enhances the production of antibodies through the activation of B cells, and favors the expression of surface nuclear antigens on keratinocytes. UV light exposure favors keratinocyte apoptosis or necroptosis, which results in the release of multiple proinflammatory cytokines, including IL-6, IL-1α, IL-1β, TNF-α, IFNs, and CXCL10. Serum levels of IL-17 are elevated in patients with ACLE, SCLE, and DLE. Evidence suggests IL-22 plays a role primarily in tissue repair rather than in inflammation. High expression of BAFF and its receptors have been found in lesioned keratinocytes of patients with CLE, and patients with CLE have lower serum levels of the regulatory cytokines TGF-β and IL-10. The chemokines CXCL9 and CXCL10 (CXCR3 ligands) have an increased expression among these patients, and their expression is correlated with IFNs levels. CXCR3 ligands recruit cytotoxic type I cells through this receptor, further supporting the death of keratinocytes via necroptosis with the subsequent release of eNAs perpetuating the inflammatory cycle. Interface dermatitis is characterized by the presence of CXCR3-positive lymphocytes. This review describes the leading cytokines and chemokines present in the circulation and skin that play a fundamental role in the pathogenesis of CLE.

Interleukin-18 and IL-18BP in inflammatory dermatological diseases

Interleukin (IL)-18, an interferon-γ inducer, belongs to the IL-1 family of pleiotropic pro-inflammatory factors, and IL-18 binding protein (IL-18BP) is a native antagonist of IL-18 in vivo, regulating its activity. Moreover, IL-18 exerts an influential function in host innate and adaptive immunity, and IL-18BP has elevated levels of interferon-γ in diverse cells, suggesting that IL-18BP is a negative feedback inhibitor of IL-18-mediated immunity. Similar to IL-1β, the IL-18 cytokine is produced as an indolent precursor that requires further processing into an active cytokine by caspase-1 and mediating downstream signaling pathways through MyD88. IL-18 has been implicated to play a role in psoriasis, atopic dermatitis, rosacea, and bullous pemphigoid in human inflammatory skin diseases. Currently, IL-18BP is less explored in treating inflammatory skin diseases, while IL-18BP is being tested in clinical trials for other diseases. Thereby, IL-18BP is a prospective therapeutic target.

Crosstalk between miR-146a and pro-inflammatory cytokines in patients with systemic lupus erythematosus

microRNA-146a (miR-146a) plays an essential role in immune anomalies and organ injury of systemic lupus erythematosus (SLE) by regulating the disease's inflammation and complications. Here, we analyzed the expression of miR-146a in SLE and a panel of pro-inflammatory cytokines (IL-1, IL-6, IL-8, IL-17, and TNF-α). Association between all measured parameters and the disease's clinical manifestation and response to treatment was monitored. Our study populations were 113 SLE patients and 104 healthy volunteers. miR-146a expression in peripheral blood mononuclear cells (PBMCs) was measured by quantitative real-time PCR (RT-qPCR). The content of the plasma cytokines (IL-1β, IL-6, IL-8, IL-17, and TNF-α) was detected by enzyme-linked immunosorbent assay (ELISA). Compared with healthy controls, miR-146a expression was significantly increased (p < 0.05) in lupus patients. The analysis of the receiver operator characteristic curve (ROC) of miR-146a showed 91% sensitivity and 70% specificity. IL-1β, IL-6, and IL-17 cytokines were significantly increased (p < 0.001), while IL-8 and TNF-α were significantly decreased (p < 0.001) in SLE patients against controls. The expression of miR-146a and TNF-α was upregulated considerably in SLE patients with severe disease activity. miR-146a expression was positively correlated with IL-6. Our results pointed to the elevation of miR-146a as a trade marker of SLE patients. Reduction of IL-8 and TNF-α in combination with an elevation of IL-1β, IL-6, and IL-17 might refer to miR-146a's dual effect in controlling inflammation in lupus. Although we shed some light on the role of miR-146a in SLE, further study is recommended to improve our results.

Multiplex Analysis of Serum Cytokine Profiles in Systemic Lupus Erythematosus and Multiple Sclerosis

Changes in cytokine profiles and cytokine networks are known to be a hallmark of autoimmune diseases, including systemic lupus erythematosus (SLE) and multiple sclerosis (MS). However, cytokine profiles research studies are usually based on the analysis of a small number of cytokines and give conflicting results. In this work, we analyzed cytokine profiles of 41 analytes in patients with SLE and MS compared with healthy donors using multiplex immunoassay. The SLE group included treated patients, while the MS patients were drug-free. Levels of 11 cytokines, IL-1b, IL-1RA, IL-6, IL-9, IL-10, IL-15, MCP-1/CCL2, Fractalkine/CX3CL1, MIP-1a/CCL3, MIP-1b/CCL4, and TNFa, were increased, but sCD40L, PDGF-AA, and MDC/CCL22 levels were decreased in SLE patients. Thus, changes in the cytokine profile in SLE have been associated with the dysregulation of interleukins, TNF superfamily members, and chemokines. In the case of MS, levels of 10 cytokines, sCD40L, CCL2, CCL3, CCL22, PDGF-AA, PDGF-AB/BB, EGF, IL-8, TGF-a, and VEGF, decreased significantly compared to the control group. Therefore, cytokine network dysregulation in MS is characterized by abnormal levels of growth factors and chemokines. Cross-disorder analysis of cytokine levels in MS and SLE showed significant differences between 22 cytokines. Protein interaction network analysis showed that all significantly altered cytokines in both SLE and MS are functionally interconnected. Thus, MS and SLE may be associated with impaired functional relationships in the cytokine network. A cytokine correlation networks analysis revealed changes in correlation clusters in SLE and MS. These data expand the understanding of abnormal regulatory interactions in cytokine profiles associated with autoimmune diseases.

Anti-galectin-3 antibodies induce skin vascular inflammation via promoting local production of IL-1β in systemic lupus erythematosus

Vascular inflammation could occur in all organs and tissues in patients with systematic lupus erythematosus (SLE), of which skin is the most frequent one. Our previous research identified anti-galectin-3 (Gal3) antibodies (Abs) as an important mediator of lupus cutaneous vasculopathy. Herein, we showed that anti-Gal3 Abs dysregulated the function of vascular endothelial cells with higher transcript levels of IL-1β and increased expression of mature IL-1β. The enhanced production of IL-1β secreted by endothelial cells was dependent on NLRP3 inflammasome. Intradermal injection of anti-Gal3 Abs in mice induced local inflammation with perivascular infiltration of T cells and neutrophils, which was inhibited by IL-1β blockade. Induction of anti-Gal3 Abs in circulation by immunization of Gal3 antigen not only led to histopathologic changes in the skin, including focal keratinocytes vacuolization and thickening of blood vessels, but also a systemic autoimmune phenotype that involves autoantibody production and kidney damage. Intriguingly, local overexpression of IL-1β was primarily associated with skin lesions but not with other internal organs in mice. Finally, we showed that the serum levels of IL-1β were comparable between SLE patients and healthy donors. Whilst the expression of IL-1β was enriched in local area with perivascular inflammation in lupus skin lesion compared to healthy normal skin. The results strongly suggest that IL-1β plays an important role in mediating anti-Gal3 Ab-induced skin vascular inflammation and raised the prospect for using IL-1β blocking therapies to treat lupus cutaneous damage.

Systematic lupus erythematous patients following COVID-19 vaccination: Its flares up and precautions

Systemic lupus erythematosus (SLE) is an autoimmune disease that can cause both direct and indirect inflammatory damage to multiple organs. Clinical symptoms in the skin, joints, kidneys, and central nervous system, as well as serological indicators such as antinuclear antibodies (ANA), notable antibodies to dsDNA, are used to diagnose SLE. mRNA SARS-CoV-2 vaccines have been shown to trigger SLE flares and the development of new rheumatic diseases. SARS-CoV-2 mRNA vaccinations increase type I interferon (INF), which is not only known to have a role in the antiviral response but is also a crucial cytokine in the pathophysiology of SLE. Furthermore, both the mRNA and adenovirus vaccines boost the production of type 1 interferons, which are required for the spread of SARS-CoV-2. The danger of not administering the COVID-19 vaccination to SLE patients is significantly larger than the likelihood of its adverse effects, which are most likely caused by intrinsic immune failure, demographic disease activity, medications, linked organ damage, and comorbidities. The adverse effects of COVID-19 vaccination in SLE patients are common (about 50%), although they do not interfere with daily functioning in the majority of cases. Several precautions can be taken to avoid the complications associated with COVID-19 vaccinations.

Thrombosis and Anticoagulation Therapy in Systemic Lupus Erythematosus

Systemic lupus erythematosus (SLE) is an autoimmune inflammatory disease in which pathogenic autoantibodies and immune complexes are formed and mediate multiple organ and tissue damage. Thrombosis is one of the most common causes of death in patients with SLE. Anticoagulant therapy blocks the vicious cycle between inflammation and thrombosis, which may greatly improve the long-term prognosis of patients with SLE. However, the etiology and pathogenesis of this disease are very complicated and have not yet been fully clarified. Therefore, in the present review, we will highlight the characteristics and mechanisms of thrombosis and focus on the anticoagulant drugs commonly used in clinical practice, thus, providing a theoretical basis for scientific and reasonable anticoagulant therapy in clinical practice.

Current Concepts on Pathogenic Mechanisms and Histopathology in Cutaneous Lupus Erythematosus

Cutaneous lupus erythematosus (CLE) is an interferon (IFN)-driven autoimmune disease that may be limited to the skin or can be associated with systemic lupus erythematosus (SLE). CLE occurs in several morphologic subtypes ranging from isolated, disc-shaped plaques to disseminated skin lesions. The typical histopathologic pattern of skin lesions is named interface dermatitis and characterized by a lymphocytic infiltrate and necroptotic keratinocytes at the dermo-epidermal junction. Other histopathologic patterns primarily involve the dermis or subcutis, depending on the subtype. One critical mechanism in CLE is the chronic reactivation of innate and adaptive immune pathways. An important step in this process is the recognition of endogenous nucleic acids released from dying cells by various pattern recognition receptors (PRRs), including Toll-like receptors (TLRs) and other cytosolic receptors. Crucial cells in CLE pathogenesis comprise plasmacytoid dendritic cells (pDCs) as major producers of type I IFN, T cells exerting cytotoxic effects, and B cells, previously believed to contribute via secretion of autoantibodies. However, B cells are increasingly considered to have additional functions, supported by studies finding them to occur in highest numbers in chronic discoid lupus erythematosus (CDLE), a subtype in which autoantibodies are often absent. More precise knowledge of how CLE subtypes differ pathophysiologically may allow a tailored pharmacotherapy in the future, taking into account the specific molecular signature in relation to the morphologic subtype.

Activation of NLRP3 Inflammasome in the Skin of Patients with Systemic and Cutaneous Lupus Erythematosus

NLRP3 inflammasome is suggested to contribute to the complex pathogenesis of systemic lupus erythematosus, but its role in cutaneous lupus erythematosus has not been addressed. This study investigated the expression of NLRP3 inflammasome components and levels of type I interferons in the skin of 20 patients with cutaneous lupus erythematosus. Expression of NLRP1/3, adaptor protein ASC (apoptosis-associated speck-like protein), caspase-1, interferon-α (IFN-α), myxovirus resistance protein (MxA), and interferon-induced proteins 1 and 2 (IFIT 1/2) in the skin was assessed using reverse transcription quantitative real-time PCR (RT-qPCR), western blotting and immunohistochemistry. Serum interferon-α protein levels from 12 patients were measured using digital enzyme-linked immunoassay (ELISA). Interleukin-1β expression was significantly upregulated in the lesional skin of patients with cutaneous lupus erythematosus compared with their uninvolved skin. However, NLRP1/3, ASC and caspase-1 were not significantly upregulated compared with the skin of control persons. IFN-α and IFN-induced proteins MxA and IFIT1/2 were strongly expressed in cutaneous lupus erythematosus skin. Variability in the expression of NLRP3 inflammasome components among patients suggests heterogeneity of pathological pathways in cutaneous lupus erythematosus.

Potential role of interleukin-33 in systemic lupus erythematosus by regulating toll like receptor 4

Introduction

Systemic lupus erythematosus (SLE) is an autoimmune disease characterized by immune activation and multi-immunologic phenotypes. Interleukin-33 (IL-33) has been shown to be a critical and pleiotropic immunoregulatory mediator in the pathogenesis of many autoimmune diseases. At present, there are conflicting findings in the research of IL-33 in SLE. The purpose of this study was to investigate whether and how IL-33 is involved in the occurrence and development of SLE.

Methods

43 SLE patients and 43 healthy volunteers were recruited for this study. Serum levels of IL-33, IL-4, IL-6, IL-10 and IL-21 were measured by ELISA. The expression of IL-33 was investigated in kidney sections by immunohistochemistry in lupus nephritis patients ( n = 5) and controls ( n = 3). The mRNA expressions of Toll like receptor 4 (TLR4), TLR2, and tumorigenicity 2 (ST2)L were quantified in peripheral blood mononuclear cells (PBMCs) by real-time PCR. The surface expression of TLR4 on T cells, B cells, monocytes, and neutrophils was assessed by flow cytometry ( n = 22). Mann–Whitney U-test and Spearman’s test were used for statistical analysis.

Results

Serum concentrations of IL-33 were significantly higher in SLE patients than in healthy controls ( p < 0.0001). IL-33 expressions were positively correlated with IL-4 and IL-6 levels in SLE patients, which play pivotal roles in the autoantibody production. In addition, TLR4 and TLR2 mRNA were markedly increased in PBMCs from SLE patients ( p < 0.05). TLR4 was positively associated with IL-33, while TLR2 was not.

Conclusions

These results imply that upregulated expression of serum IL-33 together with increased TLR4 in PBMCs may contribute to the pathogenesis of SLE via promotion of inflammatory cytokines production.

Role of the innate and adaptive immune responses in the pathogenesis of systemic lupus erythematosus

OBJECTIVE

Systemic lupus erythematosus (SLE), the most common form of lupus, is a multisystemic rheumatic disease with different clinical features that generally affect women of childbearing age. The common symptoms of SLE are very similar to other autoimmune and non-autoimmune disorders, thereby it is known as a thousand faces disease. In this article, we are going to discuss some of the most updated information about immune system-related factors, cells, and cytokines involved in SLE pathogenesis.

METHODS

Different electronic databases, especially PubMed/MEDLINE, Scopus, and Google Scholar, were searched to review and analyze relevant literature on the role of innate and adaptive immune cells and cytokines in the pathogenesis of SLE. A search for relevant literature was accomplished using various keywords including systemic lupus erythematosus, apoptosis, autoantibodies, immunopathogenesis of SLE, adaptive and innate immune cells, inflammatory cytokines, hormones, etc. RESULTS AND CONCLUSION: The most important characteristic of SLE is the production of antibodies against different nuclear autoantigens like double-strand DNA and RNA. The depositions of the immune complexes (ICs) that are generated between autoantibodies and autoantigens, along with aberrant clearance of them, can lead to permanent inflammation and contribute to tissue or organ damage. Related mechanisms underlying the initiation and development of SLE have not been clarified yet. Although, defects in immune tolerance, enhanced antigenic load, hyperactivity of T cells, and inappropriate regulation of B cells contribute to the pathogenic autoantibodies generation. Besides, sex hormones that influence the immune system seem to act as triggers or protectors of SLE development.

Increased CD69+CCR7+ circulating activated T cells and STAT3 expression in cutaneous lupus erythematosus patients recalcitrant to antimalarials

BACKGROUND

Antimalarials are first-line systemic therapy for cutaneous lupus erythematosus (CLE). While some patients unresponsive to hydroxychloroquine (HCQ) alone benefit from the addition of quinacrine (QC), a subset of patients is refractory to both antimalarials.

METHODS

We classified CLE patients as HCQ-responders, HCQ+QC-responders, or HCQ+QC-nonresponders to compare immune profiles. Immunohistochemistry, immunofluorescence, and qRT-PCR were used to characterize inflammatory cells and cytokines in lesional skin.

RESULTS

Immunohistochemistry showed that CD69⁺ T cells were higher in HCQ+QC-nonresponders compared to HCQ- and HCQ+QC-responders (p < 0.05). Immunofluorescence further identified these cells as CD69+CCR7+ circulating activated T cells. Myeloid dendritic cells were significantly higher in HCQ+QC-responders compared to both HCQ-responders and HCQ+QC-nonresponders. Plasmacytoid dendritic cells were significantly increased in HCQ-responders compared to HCQ- and HCQ+QC-nonresponders. No differences were found in the number of autoreactive T cells, MAC387+ cells, and neutrophils among the groups. CLASI scores of the HCQ+QC-nonresponder group positively correlated with CD69+CCR7+ circulating activated T cells (r = 0.6335, p < 0.05) and MAC387+ cells (r = 0.5726, p < 0.05). IL-17 protein expression was higher in HCQ+QC-responders compared to HCQ-responders or HCQ+QC-nonresponders, while IL-22 protein expression did not differ. mRNA expression demonstrated increased STAT3 expression in a subset of HCQ+QC-nonresponders.

CONCLUSION

An increased number of CD69+CCR7+ circulating activated T cells and a strong correlation with CLASI scores in the HCQ+QC-nonresponders suggest these cells are involved in antimalarial-refractory skin disease. STAT3 is also increased in HCQ+QC-nonresponders and may also be a potential target for antimalarial-refractory skin disease.

Using Gene Expression Analysis to Understand Complex Autoimmune Skin Disease Patients: A Series of Four Canine Cutaneous Lupus Erythematosus Cases

Cutaneous Lupus Erythematosus (CLE) is an autoimmune skin disease that occurs in almost two-thirds of people with Systemic Lupus Erythematosus (SLE) and can exist as its own entity. Despite its negative impact on the quality of life of patients, lupus pathogenesis is not fully understood. In recent years, the role of gene expression analysis has become important in understanding cellular functions and disease causation within and across species. Interestingly, dogs also develop CLE, providing a spontaneous animal model of disease. Here, we present a targeted transcriptomic analysis of skin biopsies from a case series of four dogs with complex autoimmunity with suspected CLE. We identified 92 differentially expressed genes (DEGs), including type 1 interferon, B cell, and T cell-related genes, in the four cases compared to healthy skin margin controls. Additionally, we compared our results with existing CLE datasets from humans and mice and found that humans and canines share 49 DEGs, whereas humans and mice shared only 25 DEGs in our gene set. Immunohistochemistry of IFNG and CXCL10, two of the most highly upregulated inflammatory mediators, confirmed protein-level expression and revealed immune cells as the primary source of CXCL10 in dogs with SLE, whereas keratinocytes stained strongly for CXCL10 in dogs without SLE. We propose that gene expression analysis may aid the diagnosis of complex autoimmune skin diseases and that dogs may provide important insights into CLE and SLE pathogeneses, or more broadly, skin manifestations during systemic autoimmunity.

Identification of Serum Biomarkers and Pathways of Systemic Lupus Erythematosus with Skin Involvement Through GC/MS-Based Metabolomics Analysis

Purpose

Skin involvement is the second most common symptom of systemic lupus erythematosus (SLE), and the prevention of skin lesion development might benefit to lessen the system inflammation burden in SLE. However, the mechanisms of skin lesion in SLE remain unclear.

Patients and Methods

Metabolome based on gas chromatography-mass spectrometry (GC-MS) was used for comparison of serum metabolism among 11 SLE patients with skin lesion (SL), 10 SLE patients without skin lesion (SNL), and 16 healthy controls (HC). The analysis of metabolism profiles was through LUG database, Human Metabolome Database (HMDB) as well as Kyoto Encyclopedia of Genes and Genomes (KEGG).

Results

A total of 14 most meaningful metabolites were found in SL patients compared to SNL patients, and 19 metabolic pathways were enriched. Meanwhile, L-alpha-aminobutyric acid, dehydroascorbic acid, glycine, and L-tyrosine achieved an area under receiver-operating characteristic (ROC) curve of 0.8636, 0.8091, 0.7727, and 0.7636, respectively, indicating their diagnostic potential for SL patients. In addition, the combined model of L-alpha-aminobutyric acid and dehydroascorbic acid provided better diagnostic accuracy.

Conclusion

The metabolomic features of SLE patients with skin lesion could be detected by GC/MS assay. Our study tried to provide new insights into the mechanism of SLE skin injury. Further validation of these findings through larger sample size studies may contribute to the use of metabolic profile analysis.

Interleukin-31: The "itchy" cytokine in inflammation and therapy

The cytokine interleukin-31 has been implicated in the pathophysiology of multiple atopic disorders such as atopic dermatitis (AD), allergic rhinitis, and airway hyper-reactivity. In AD, IL-31 has been identified as one of the main "drivers" of its cardinal symptom, pruritus. Here, we summarize the mechanisms by which IL-31 modulates inflammatory and allergic diseases. T_H 2 cells play a central role in AD and release high levels of T_H 2-associated cytokines including IL-31, thereby mediating inflammatory responses, initiating immunoregulatory circuits, stimulating itch, and neuronal outgrowth through activation of the heterodimeric receptor IL-31 receptor A (IL31RA)/Oncostatin M receptor (OSMRβ). IL31RA expression is found on human and murine dorsal root ganglia neurons, epithelial cells including keratinocytes and various innate immune cells. IL-31 is a critical cytokine involved in neuroimmune communication, which opens new avenues for cytokine modulation in neuroinflammatory diseases including AD/pruritus, as validated by recent clinical trials using an anti-IL-31 antibody. Accordingly, inhibition of IL-31-downstream signaling may be a beneficial approach for various inflammatory diseases including prurigo. However, as to whether downstream JAK inhibitors directly block IL-31-mediated-signaling needs to be clarified. Targeting the IL-31/IL31RA/OSMRβ axis appears to be a promising approach for inflammatory, neuroinflammatory, and pruritic disorders in the future.

Bioinformatics analyses of gene expression profile identify key genes and functional pathways involved in cutaneous lupus erythematosus

BACKGROUND

Lupus erythematosus is an autoimmune disease that causes damage to multiple organs ranging from skin lesions to systemic manifestations. Cutaneous lupus erythematosus (CLE) is a common type of lupus erythematosus (LE), but its molecular mechanisms are currently unknown. The study aimed to explore changes in the gene expression profiles and identify key genes involved in CLE, hoping to uncover its molecular mechanism and identify new targets for CLE.

METHOD

We analyzed the microarray dataset (GSE109248) derived from the Gene Expression Omnibus (GEO) database, which was a transcriptome profiling of CLE cutaneous lesions. The differentially expressed genes (DEGs) were identified, and the functional annotation of DEGs was performed with Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses. Protein-protein interaction (PPI) network was also constructed to identify hub genes involved in CLE.

RESULT

A total of 755 up-regulated DEGs and 405 down-regulated DEGs were identified. GO enrichment analysis showed that defense response to virus, immune response, and type I interferon signaling pathway were the most significant enrichment items in DEGs. The KEGG pathway analysis identified 51 significant enrichment pathways, which mainly included systemic lupus erythematosus, osteoclast differentiation, cytokine-cytokine receptor interaction, and primary immunodeficiency. Based on the PPI network, the study identified the top 10 hub genes involved in CLE, which were CXCL10, CCR7, FPR3, PPARGC1A, MMP9, IRF7, IL2RG, SOCS1, ISG15, and GSTM3. By comparison between subtypes, the results showed that ACLE had the least DEGs, while CCLE showed the most gene and functional changes.

CONCLUSION

The identified hub genes and functional pathways found in this study may expand our understanding on the underlying pathogenesis of CLE and provide new insights into potential biomarkers or targets for the diagnosis and treatment of CLE. Key Points • The bioinformatics analysis based on CLE patients and healthy controls was performed and 1160 DEGs were identified • The 1160 DEGs were mainly enriched in biological processes related to immune responses, including innate immune response, type I interferon signaling pathway, interferon-γ-mediated signaling pathway, positive regulation of T cell proliferation, regulation of immune response, antigen processing, and presentation via MHC class Ib and so on • KEGG pathway enrichment analysis indicated that DEGs were mainly enriched in several immune-related diseases and virus infection, including systemic lupus erythematosus, primary immunodeficiency, herpes simplex infection, measles, influenza A, and so on • The hub genes such as CXCL10, IRF7, MMP9, CCR7, and SOCS1 may become new markers or targets for the diagnosis and treatment of CLE.

Cutaneous and systemic connections in lupus

PURPOSE OF REVIEW

Systemic lupus erythematosus (SLE) is a systemic autoimmune disease with multiple manifestations, with a majority of SLE patients having cutaneous involvement. Despite ongoing research, the relationship between SLE and cutaneous lupus erythematosus (CLE) pathogeneses remains unknown. This review will compare advances in understanding the cause and pathogenesis of SLE and CLE.

RECENT FINDINGS

Recently, mechanisms by which immune cell populations contribute to the pathogenesis of SLE and CLE have been queried. Studies have pointed to transitional B cells and B-cell activating factor (BAFF) signaling as potential drivers of SLE and CLE, with belimumab clinical data supporting these hypotheses. Ustekinumab trials and an exciting regulatory T cell (Treg) adoptive transfer in an SLE patient with cutaneous disease have suggested a role for T-cell-targeted therapies. The theory that neutrophil extracellular traps may be a source of autoantigens in SLE remains controversial, while neutrophils have been suggested as early drivers of cutaneous disease. Finally, plasmacytoid dendritic cells (pDCs) have been studied as a potential therapeutic target in SLE, and anti-blood DC antigen (anti-BDCA) antibody clinical trials have shown promise in treating cutaneous disease.

SUMMARY

Although recent findings have contributed to understanding SLE and CLE pathogenesis, the mechanistic link between these diseases remains an area requiring further research.

Immunopathogenesis of skin injury in systemic lupus erythematosus

PURPOSE OF REVIEW

Skin injury is the most common clinical manifestation of SLE and is disfiguring, difficult to treat, and incompletely understood. We provide an overview of recently published articles covering the immunopathogenesis of skin injury in SLE.

RECENT FINDINGS

Skin of SLE has an inherent susceptibility to apoptosis, the cause of which may be multifactorial. Chronic IFN overexpression leads to barrier disruption, infiltration of inflammatory cells, cytokine production, and release of autoantigens and autoantibody production that result in skin injury. Ultraviolet light is the most important CLE trigger and amplifies this process leading to skin inflammation and potentially systemic disease flares.

SUMMARY

The pathogenesis of skin injury in CLE is complex but recent studies highlight the importance of mechanisms driving dysregulated epidermal cell death likely influenced by genetic risk factors, environmental triggers (UV light), and cytotoxic cells and cellular signaling.

Bioengineered Skin Intended as In Vitro Model for Pharmacosmetics, Skin Disease Study and Environmental Skin Impact Analysis

This review aims to be an update of Bioengineered Artificial Skin Substitutes (BASS) applications. At the first moment, they were created as an attempt to replace native skin grafts transplantation. Nowadays, these in vitro models have been increasing and widening their application areas, becoming important tools for research. This study is focus on the ability to design in vitro BASS which have been demonstrated to be appropriate to develop new products in the cosmetic and pharmacology industry. Allowing to go deeper into the skin disease research, and to analyze the effects provoked by environmental stressful agents. The importance of BASS to replace animal experimentation is also highlighted. Furthermore, the BASS validation parameters approved by the OECD (Organisation for Economic Co-operation and Development) are also analyzed. This report presents an overview of the skin models applicable to skin research along with their design methods. Finally, the potential and limitations of the currently available BASS to supply the demands for disease modeling and pharmaceutical screening are discussed.

Cytokinocytes: the diverse contribution of keratinocytes to immune responses in skin

The skin serves as the primary interface between our body and the external environment and acts as a barrier against entry of physical agents, chemicals, and microbes. Keratinocytes make up the main cellular constitute of the outermost layer of the skin, contributing to the formation of the epidermis, and they are crucial for maintaining the integrity of this barrier. Beyond serving as a physical barrier component, keratinocytes actively participate in maintaining tissue homeostasis, shaping, amplifying, and regulating immune responses in skin. Keratinocytes act as sentinels, continuously monitoring changes in the environment, and, through microbial sensing, stretch, or other physical stimuli, can initiate a broad range of inflammatory responses via secretion of various cytokines, chemokines, and growth factors. This diverse function of keratinocytes contributes to the highly variable clinical manifestation of skin immune responses. In this Review, we highlight the highly diverse functions of epidermal keratinocytes and their contribution to various immune-mediated skin diseases.

The pathogenesis of cutaneous lupus erythematosus: The aberrant distribution and function of different cell types in skin lesions

Cutaneous lupus erythematosus (CLE) is an autoimmune disease with a broad range of cutaneous manifestations. In skin lesions of CLE, keratinocytes primarily undergo apoptosis. Interferon-κ(IFN-κ) is belonged to type I interferons (type I IFNs) and is selectively produced by keratinocytes. Recently, keratinocytes selectively produced IFN-κ is identified to be a key to trigger type I interferon responses in CLE. Other immune cells such as plasmacytoid dendritic cells (pDCs) are identified to be relevant origin of type I interferons (type I IFNs) which are central to the development of CLE lesions and responsible for mediating Th1 cell activity. Other types of cells such as neutrophils, B cells and Th17 cells also are involved in the development of this disease. The close interaction of those cells composes a comprehensive and complicated network in CLE. In this review, we discussed the aberrant distribution and function of different cells types involved in this disease and will offer a new direction for research and therapy in the near future.

Staphylococcus aureus Colonization Is Increased on Lupus Skin Lesions and Is Promoted by IFN-Mediated Barrier Disruption

Cutaneous inflammation is recurrent in systemic lupus erythematosus (SLE), yet mechanisms that drive cutaneous inflammation in SLE are not well defined. Type I IFNs are elevated in nonlesional SLE skin and promote inflammatory responses. Staphylococcus aureus, known to induce IFN production, could play a role in cutaneous inflammation in SLE. We show here that active cutaneous lupus erythematosus lesions are highly colonized (∼50%) by S. aureus. To define the impact of IFNs on S. aureus colonization, we examined the effects of type I and type II IFNs on S. aureus adherence and invasion. An increase in adherent S. aureus was observed after exposure to both IFN-α and -γ, whereas IFN-γ appeared to inhibit invasion of S. aureus. Cutaneous lupus erythematosus lesional skin microarray data and RNA sequencing data from SLE keratinocytes identified repression of barrier gene expression, such as filaggrin and loricrin, and SLE keratinocytes exhibited increased S. aureus-binding integrins. These SLE-associated changes could be replicated by IFN treatment of keratinocytes. Further, SLE keratinocytes exhibited increased binding to S. aureus. Together, these data suggest that chronic exposure to IFNs induces barrier disruption that allows for higher S. aureus colonization in SLE skin.

Cutaneous lupus erythematosus induced by drugs - novel insights

Introduction: There is a growing list of drugs implicated in inducing both subacute and chronic forms of cutaneous lupus erythematosus. It is important to recognize these drugs in order to quickly treat patients with drug induced disease.Areas covered: This paper reviews the current literature describing drugs implicated in causing cutaneous lupus erythematosus. A Pubmed search was used to compile a list of medications implicated up to August 2019. It reviews new classes of drugs identified as causing cutaneous lupus erythematosus, the pathophysiology of the disease process, and current recommendations for treatment of the disease.Expert opinion: Many drugs have been identified as inducing lupus, and many more continue to be described in new reports. Further research is needed to understand this phenomenon, which will aid in the diagnosis and treatment of affected patients.

IMMUNOINFLAMMATORY RHEUMATIC DISEASES ASSOCIATED WITH TYPE I INTERFERON: NEW EVIDENCE

Immunoinflammatory rheumatic diseases (IIRDs) are a large group of pathological conditions with impaired immunological tolerance to autogenous tissues, leading to inflammation and irreversible organ damage. The review discusses current ideas on the role of type I interferons in the immunopathogenesis of IIRDs, primarily systemic lupus erythematosus, and new possibilities for personalized therapy.

Non-invasive Approaches for the Diagnosis of Autoimmune/Autoinflammatory Skin Diseases-A Focus on Psoriasis and Lupus erythematosus

The traditional diagnostic gold standard for inflammatory skin lesions of unclear etiology is dermato-histopathology. As this approach requires an invasive skin biopsy, biopsy processing and analysis by specialized histologists, it is a resource intensive approach requiring trained healthcare professionals. In many health care settings access to this diagnostic approach can be difficult and outside emergency cases will usually take several weeks. This scenario leads to delayed or inappropriate treatment given to patients. With dramatically increased sensitivity of a range of analysis systems including mass spectrometry, high sensitivity, multiplex ELISA based systems and PCR approaches we are now able to "measure" samples with unprecedented sensitivity and accuracy. Other important developments include the long-term monitoring of parameters using microneedle approaches and the improvement in imaging systems such as optical coherence tomography. In this review we will focus on recent achievements regarding measurements from non-invasive sampling, in particular from plucked hair and skin tape-strips which seem well suited for the diagnosis of lupus erythematosus and psoriatic inflammation, respectively. While these approaches will not replace clinical observation-they can contribute to improved subgroup diagnosis, stratified therapeutic approaches and have great potential for providing molecular and mechanistic insight in to inflammatory skin diseases.

MicroRNA-146a inhibits NF-κB activation and pro-inflammatory cytokine production by regulating IRAK1 expression in THP-1 cells

MicroRNA (miR)-146a levels are reduced in peripheral blood mononuclear cells of patients with systemic lupus erythematosus (SLE); however, its function is not well understood. The present study investigated the role of miR-146a in the regulation of lipopolysaccharide (LPS)-induced inflammation in THP-1 cells. A miR-146a mimic and an inhibitor were used to overexpress and downregulate miR-146a expression, respectively. Reverse transcription-quantitative PCR and western blot analyses were performed to evaluate interleukin (IL)-1 receptor-associated kinase 1 (IRAK1) expression, and western blot analysis was applied to assess nuclear factor-κB activation by analyzing p65 subunit levels in the nucleus. To investigate the effects of miR-146a on LPS-induced inflammation, IL-6 and tumor necrosis factor-α (TNF-α) levels were also measured using ELISA. The results of the present study revealed thatmiR-146a overexpression significantly reduced IRAK1 expression, reduced p65 levels in the nucleus and reduced IL-6 and TNF-α levels in the supernatant of the cell culture medium of THP-1 cells following LPS treatment. Luciferase assays confirmed IRAK1 to be a direct target of miR-146a in THP-1 cells. In conclusion, miR-146a may regulate IRAK1 expression and inhibit the activation of inflammatory signals and secretion of pro-inflammatory cytokines. The present study revealed, at least in part, the mechanisms by which miR-146a regulate the inflammatory response in SLE.

Tyrosine Kinases in Autoimmune and Inflammatory Skin Diseases

Tyrosine kinases relay signals from diverse leukocyte antigen receptors, innate immune receptors, and cytokine receptors, and therefore mediate the recruitment and activation of various leukocyte populations. Non-receptor tyrosine kinases of the Jak, Src, Syk, and Btk families play major roles in various immune-mediated disorders, and small-molecule tyrosine kinase inhibitors are emerging novel therapeutics in a number of those diseases. Autoimmune and inflammatory skin diseases represent a broad spectrum of immune-mediated diseases. Genetic and pharmacological studies in humans and mice support the role of tyrosine kinases in several inflammatory skin diseases. Atopic dermatitis and psoriasis are characterized by an inflammatory microenvironment which activates cytokine receptors coupled to the Jak-Stat signaling pathway. Jak kinases are also implicated in alopecia areata and vitiligo, skin disorders mediated by cytotoxic T lymphocytes. Genetic studies indicate a critical role for Src-family kinases and Syk in animal models of autoantibody-mediated blistering skin diseases. Here, we review the various tyrosine kinase signaling pathways and their role in various autoimmune and inflammatory skin diseases. Special emphasis will be placed on identification of potential therapeutic targets, as well as on ongoing preclinical and clinical studies for the treatment of inflammatory skin diseases by small-molecule tyrosine kinase inhibitors.

Plucked hair follicles from patients with chronic discoid lupus erythematosus show a disease-specific molecular signature

OBJECTIVE

When faced with clinical symptoms of scarring alopecia-the standard diagnostic pathway involves a scalp biopsy which is an invasive and expensive procedure. This project aimed to assess if plucked hair follicles (HFs) containing living epithelial cells can offer a non-invasive approach to diagnosing inflammatory scalp lesions.

METHODS

Lesional and non-lesional HFs were extracted from the scalp of patients with chronic discoid lupus erythematosus (CDLE), psoriasis and healthy controls. RNA was isolated from plucked anagen HFs and microarray, as well as quantitative real-time PCR was performed.

RESULTS

Here, we report that gene expression analysis of only a small number of HF plucked from lesional areas of the scalp is sufficient to differentiate CDLE from psoriasis lesions or healthy HF. The expression profile from CDLE HFs coincides with published profiles of CDLE from skin biopsy. Genes that were highly expressed in lesional CDLE corresponded to well-known histopathological diagnostic features of CDLE and included those related to apoptotic cell death, the interferon signature, complement components and CD8+ T-cell immune responses.

CONCLUSIONS

We therefore propose that information obtained from this non-invasive approach are sufficient to diagnose scalp lupus erythematosus. Once validated in routine clinical settings and compared with other scarring alopecias, this rapid and non-invasive approach will have great potential for paving the way for future diagnosis of inflammatory scalp lesions.

Vitamin D receptor expression in peripheral blood mononuclear cells is inversely associated with disease activity and inflammation in lupus patients

OBJECTIVE

Systemic lupus erythematosus (SLE) is characterized by uncontrolled production of pro-inflammatory cytokines. Vitamin D receptor (VDR) has potent anti-inflammatory activities. The aim of this study was to examine the correlation between VDR expression and inflammation and disease activity in patients with SLE.

METHODS

Ninety-five SLE patients were recruited and divided into two groups, active and inactive, according to their SLE disease activity index (SLEDAI)-2 K, and 40 healthy individuals served as controls. The expression of VDR and NF-κB p65 in peripheral blood mononuclear cells (PBMCs) was determined by quantitative RT-PCR and Western blotting. VDR expression was correlated with inflammatory and diseases parameters in SLE patients. VDR regulation was also studied in THP-1 and Jurkat cell lines.

RESULTS

PBMC VDR expression was downregulated in SLE patients, especially in the active SLE group. VDR mRNA levels were negatively correlated with SLEDAI-2 K (r = - 0.348, P = 0.001), Systemic Lupus International Collaborating Clinics (SLICC) renal activity scores (r = - 0.346, P = 0.014), and proteinuria (r = - 0.309, P = 0.002) and positively associated with serum complement C3 levels (r = 0.316, P = 0.002). Multiple stepwise regression analysis indicated that PBMC VDR downregulation was an independent risk factor for SLEDAI-2 K. VDR levels were also negatively correlated with NF-κB p65 (r = - 0.339, P = 0.001), TNF-α (r = - 0.268, P = 0.009), and IL-6 (r = - 0.313, P = 0.002) levels. In monocyte and T lymphocyte cell lines, TNF-α suppressed VDR expression, whereas 1,25-dihydroxyvitamin D blocked TNF-α-induced VDR downregulation.

CONCLUSION

PBMC VDR expression is inversely associated with disease activity and inflammation in SLE patients, and VDR downregulation is likely driven by inflammation.

Photosensitivity and photoprotection in patients with lupus erythematosus

Lupus erythematosus (LE) represents a spectrum of inflammatory autoimmune disease comprising varying clinical entities ranging from primary cutaneous to systemic disease. There is a clear relationship between ultraviolet irradiation (UVR) and the clinical manifestations of LE in both adult and pediatric populations. Although it has been established that UVR exacerbates pre-existing LE, it remains unclear whether UVR induces the development of the disease. This review serves to discuss effective photoprotective measures in LE and describe the pathogenic relationship of UVR and LE.

Advancing understanding, diagnosis, and therapies for cutaneous lupus erythematosus within the broader context of systemic lupus erythematosus

Cutaneous lupus erythematosus (CLE) is an autoimmune disease that can be associated with systemic lupus erythematosus (SLE) symptoms. The pathogenesis of both CLE and SLE is multifactorial, involving genetic susceptibility, environmental factors, and innate and adaptive immune responses. Despite the efficacy of current medications, many patients remain refractory, highlighting the necessity for new treatment options. Unfortunately, owing to challenges related in part to trial design and disease heterogeneity, only one new biologic in the last 50 years has been approved by the US Food and Drug Administration for the treatment of SLE. Thus, although SLE and CLE have a similar pathogenesis, patients with CLE who do not meet criteria for SLE cannot benefit from this advancement. This article discusses the recent trials and emphasizes the need to include patients with single-organ lupus, such as CLE, in SLE trials.

Protective Effects of Kuding Tea (Ilex kudingcha C. J. Tseng) Polyphenols on UVB-Induced Skin Aging in SKH1 Hairless Mice

In this study, the protective effects of Kuding tea polyphenols (KTPs) on ultraviolet B (UVB)-induced skin injury of SKH1 hairless mice were studied. The ion precipitation method was used for extraction of polyphenols from Kuding tea. High-performance liquid chromatography showed that KTPs contains chlorogenic acid, cryptochlorogenic acid, isochlorogenic acid B, isochlorogenic acid A, and isochlorogenic acid C. SKH1 hairless mice were induced skin aging using 2.0 mW/s intensity of 90 mJ/cm² UV light once a day for seven weeks. The 2.5% and 5% KTPs solution was smeared on 2 cm² of back skin of skin aging mice twice a day. Mouse experiments showed that KTP strongly increased the serum levels of total superoxide dismutase (T-SOD) and catalase (CAT) and reduced those of malondialdehyde, interleukin 6 (IL-6), IL-1β, and tumor necrosis factor alpha (TNF-α) in mice with UVB-induced skin damage. KTP also increased the levels of type 1 collagen (Col I), hydroxyproline, and hyaluronic acid and reduced those of Col III and hydrogen peroxide in the damaged skin tissues of mice. Pathological observations of tissues stained with H & E, Masson’s trichrome, Verhoeff, and toluidine blue showed that KTPs could protect skin cells, collagen, and elastin and decrease the number of mast cells, thus inhibiting skin damage. Quantitative PCR and western blot assays showed that KTP upregulated the mRNA and protein expression of tissue inhibitor of metalloproteinase 1 (TIMP-1), TIMP-2, copper/zinc-SOD, manganese-SOD, CAT, and glutathione peroxidase and downregulated the expression of matrix metalloproteinase 2 (MMP-2) and MMP-9. In addition, the same concentration of KTP had stronger protective effects than vitamin C. The results of this study demonstrate that KTPs have good skin protective effects, as they are able to inhibit UVB-induced skin damage.

Differential expression of interferon-induced genes and other tissue-based biomarkers in acute graft-versus-host disease vs. lupus erythematosus in skin

BACKGROUND

In both acute graft-versus-host disease (GVHD) and lupus erythematosus (LE), the patient's own tissues are subjected to immunological assault via complex mechanisms influenced by interferon (IFN) and other cytokines. Although not typically confused clinically, these entities have overlapping histopathological findings in the skin.

AIM

To assess whether GVHD can be differentiated from LE using molecular methods on skin specimens.

METHODS

We developed a quantitative reverse transcription PCR assay based on previously identified tissue-based biomarkers of cutaneous GVHD, and compared gene expression in GVHD with that in LE.

RESULTS

Both entities showed robust expression of IFN-induced genes and of genes encoding proteins involved in antigen presentation, cell signalling and tissue repair. Levels of gene expression differed significantly in GVHD compared with LE, particularly those of IFN-induced genes such as MX1, OAS3, TAP1 and STAT3 (P < 0.01). Three logistic regression models could differentiate the two entities with a high degree of certainty (receiver operating characteristic area under the curve of 1.0).

CONCLUSION

The study demonstrates the feasibility of distinguishing between microscopically similar inflammatory dermatoses using tissue-based molecular techniques.

DNA Damage and Deficiencies in the Mechanisms of Its Repair: Implications in the Pathogenesis of Systemic Lupus Erythematosus

Systemic lupus erythematosus (SLE) is a perplexing and potentially severe disease, the pathogenesis of which is yet to be understood. SLE is considered to be a multifactorial disease, in which genetic factors, immune dysregulation, and environmental factors, such as ultraviolet radiation, are involved. Recently, the description of novel genes conferring susceptibility to develop SLE even in their own (monogenic lupus) has raised the interest in DNA dynamics since many of these genes are linked to DNA repair. Damage to DNA induces an inflammatory response and eventually triggers an immune response, including those targeting self-antigens. We review the evidence that indicates that patients with SLE present higher levels of DNA damage than normal subjects do and that several proteins involved in the preservation of the genomic stability show polymorphisms, some of which increase the risk for SLE development. Also, the experience from animal models reinforces the connection between DNA damage and defective repair in the development of SLE-like disease including characteristic features such as anti-DNA antibodies and nephritis. Defining the role of DNA damage response in SLE pathogenesis might be strategic in the quest for novel therapies.

Cutaneous Lupus: A Brief Review of Old and New Medical Therapeutic Options

Systemic lupus erythematosus is a chronic inflammatory condition which affects predominantly women in their 30s. It has several clinical manifestations, including skin lesions that can be classified as acute cutaneous lupus erythematosus, subacute cutaneous lupus erythematosus, and chronic cutaneous lupus erythematosus. A multifaceted approach to treating cutaneous lupus is advocated.