High expression of B lymphocyte stimulator in lesional keratinocytes of patients with cutaneous lupus erythematosus

Belimumab, an anti‐B lymphocyte stimulator (BLyS) monoclonal antibody, is approved for systemic lupus erythematosus; however, it is unclear if it can be used to treat specific skin lesions in this disease. In this analysis, we investigated the expression of BLyS and its receptors in skin lesions of different subtypes of cutaneous lupus erythematosus (CLE) using immunohistochemistry and gene expression analyses. Compared to healthy controls, the expression of BLyS was significantly higher in skin lesions of all included CLE subtypes. Similar results were seen for the BLyS receptors BAFF‐R and BCMA. Moreover, CLE‐typical pro‐inflammatory mediators (immunostimulatory DNAs) significantly enhanced the BLyS expression of keratinocytes in vitro. This study suggests a potential role for BLyS as therapeutic target in the treatment of CLE skin lesions.     

JAK inhibitor ruxolitinib inhibits the expression of cytokines characteristic of cutaneous lupus erythematosus

This study was stimulated by the clinical observation of a rapid response of a chilblain lupus patient to treatment with JAK1/2‐kinase inhibitor ruxolitinib. We investigated the in vivo expression of phospho‐JAK2 in CLE skin samples as well as the immunomodulatory in vitro effect of ruxolitinib in cultured immortalized keratinocytes and in a 3D human epidermis model (epiCS). Our results demonstrate that ruxolitinib significantly decreases the production of CLE‐typical cytokines (CXCL10, CXCL9, MxA) and might be a promising drug for future clinical studies in patients with CLE and related autoimmune skin diseases.     

Expression of interleukin-17 is correlated with interferon-α expression in cutaneous lesions of lupus erythematosus

Background. Type I interferon (IFN) has been reported to have an important role in the development of cutaneous lupus erythematosus (CLE) and systemic lupus erythematosus (SLE). A new subset of CD4+ T cells, T helper (Th)17 cells, also plays a role in the development of autoimmunity. Aim. To investigate expression of interleukin (IL)‐17 and IFN‐α in different CLE subsets, and their associations with the pathogenesis of LE. Methods. Skin tissue samples from 33 cases, including chronic discoid LE (n = 24), acute (A)CLE (n = 4), subacute CLE (n = 1) and lupus panniculitis (n = 4) were collected for immunohistochemistry. Expression of IL‐6, IL‐17A, IFN‐α, IFN‐γ, myxovirus protein (Mx)A and transforming growth factor (TGF)‐β was assessed in these samples. Results. All LE specimens had staining for IL‐6 and TGF‐β in the infiltrated inflammatory cells. IL‐17A staining was seen in 84.8% of specimens, and IFN‐α or MxA was seen in 93.9%. TGF‐β expression in ACLE was significantly greater than that in both chronic cutaneous (CC)LE and in lupus panniculitis (P = 0.02 for both). Expression of IL‐17A was positively associated with expression of IFN‐α and MxA (Spearman’s ρ = 0.56 and 0.39, respectively). In addition, the Cutaneous Lupus Erythematosus Disease Area and Severity Index (CLASI) correlated positively with expression of IFN‐α and MxA (ρ = 0.40 for both), whereas there was no correlation with IL‐17A expression. Conclusions. Two major cytokines, IL‐17A and IFN‐α, may play roles in the pathogenesis of CLE. Their patterns of expression positively correlated with each other.     

A possible inhibitory action of diaminodiphenyl sulfone on tumour necrosis factor-alpha production from activated mononuclear cells on cutaneous lupus erythematosus

Background. We have previously reported that diaminodiphenyl sulfone (DDS; dapsone) can bring about significant clinical improvement in patients with cutaneous lupus erythematosus (CLE). However, the pharmacological actions of DDS in the skin lesion of patients with CLE are still unknown. Objective. In this study, we aimed to clarify the pharmacological actions of DDS on CLE. Methods. We conducted an in vitro study to examine the effects of DDS on the mRNA expression and production of cytokines on lipopolysaccharide‐stimulated peripheral blood mononuclear cells. Results. DDS suppressed mRNA expression of tumour necrosis factor (TNF)‐α and significantly decreased the level of TNF‐α in culture supernatant. Conclusions. DDS may exert an anti‐inflammatory action by suppressing TNF‐α produced by activated mononuclear cells.     

Recent advances in cytokines in cutaneous and systemic lupus erythematosus

Lupus erythematosus (LE) includes a broad spectrum of diseases from a cutaneous‐limited type to a systemic type. Systemic lupus erythematosus (SLE) is a systemic autoimmune disease which affects multiple organs. Cutaneous lupus erythematosus (CLE) includes skin symptoms seen in SLE and cutaneous‐limited LE. Although immune abnormalities, as well as heritable, hormonal and environmental factors, are involved in the pathology of LE, the actual pathogenesis is still unclear. Recently, the involvement of various cytokines has been shown in the pathogenesis of LE. Moreover, some trials with biological agents targeted specific cytokines are also ongoing for SLE. In this article, we review the contributions of major cytokines such as interferon, tumor necrosis factor‐α and interleukin‐18 to LE, especially SLE and CLE.     

Clinical Manifestations of Cutaneous Lupus Erythematosus

Cutaneous lupus erythematosus (CLE) is a chronic inflammatory autoimmune disease with a broad spectrum of clinical manifestations and a variable course. In numerous investigations, it has been shown that exogenous factors, such as UV‐light and drugs, can induce this disease. However, not all clinical aspects can be explained and therefore, the pathogenesis of CLE is currently under extensive research. The various cutaneous manifestations of LE are divided into LE‐nonspecific and LE‐specific skin disease based on histologic criteria. LE‐nonspecific manifestations are mostly associated with systemic LE but can also occur in other diseases and include particularly vascular skin lesions such as pe‐riungual telangiectases. LE‐specific skin disease includes the subtypes of CLE such as acute cutaneous LE (ACLE), subacute cutaneous LE (SCLE), chronic cutaneous LE (CCLE), and intermittent CLE (ICLE). The subdivision of these subtypes with different prognosis and course is supported by genetic, clinical, histologic, and immunoserologic findings. The subtypes of CLE require a specific morphological and clinical analysis, which is described in the first part of this review. In the second part of this review, further diagnostic procedures and therapeutic strategies in patients with CLE are discussed.     

Apoptotic signal molecules in skin biopsies of cutaneous lupus erythematosus: analysis using tissue microarray

Cutaneous lupus erythematosus (CLE) is a heterogeneous autoimmune disease. Different pathogenetic mechanisms, including the accumulation of apoptotic keratinocytes in CLE, have been reported. Therefore, we investigated whether CLE and other inflammatory skin diseases differ with regard to the epidermal expression of molecules that are crucial for the initiation and regulation of apoptosis. In this study, 241 skin biopsies from patients with CLE, psoriasis (PSO), lichen planus (LP) and healthy controls (HCs) were analysed immunohistochemically using the tissue microarray (TMA) technique. The TUNEL assay and anti‐activated caspase‐3 antibodies revealed a significant increase of apoptotic keratinocytes in CLE lesions compared with HCs. Furthermore, we detected a significant increase in the epidermal expression of CD95 in CLE specimens compared with PSO, LP and HCs. These data suggest that the accumulation of apoptotic keratinocytes in CLE might be due to the increased epidermal expression of CD95, resulting in increased activity of the extrinsic apoptotic pathway in the disease.     

Heparinoid suppresses Der p‐induced IL‐1β production by inhibiting ERK and p38 MAPK pathways in keratinocytes

Epidermal keratinocytes initiate skin inflammation by activating immune cells. The skin barrier is disrupted in atopic dermatitis (AD) and epidermal keratinocytes can be exposed to environmental stimuli, such as house dust mite (HDM) allergens. We showed previously that HDM allergens activate the NLRP3 inflammasome of keratinocytes, thereby releasing pro‐inflammatory cytokines. Heparinoid is an effective moisturizer for atopic dry skin. However, a recent report showed that heparinoid treatment can improve inflammation of lichen planus. Therefore, we hypothesized that it acts on epidermal keratinocytes not only as a moisturizer, but also as a suppressant of the triggers of skin inflammation. We found that HDM allergen‐induced interleukin (IL)‐1β release from keratinocytes was inhibited significantly by heparinoid pretreatment without affecting cell viability. However, heparinoid did not affect caspase‐1 release, suggesting that heparinoid did not affect HDM allergen‐induced inflammasome activation. Heparinoid treatment not only decreased intracellular levels of pro‐IL‐1β, but also suppressed IL‐1β messenger RNA (mRNA) expression in keratinocytes. Among the intracellular signalling pathways, the activation of extracellular signal‐regulated kinase and p38 pathways, which are required for IL‐1β expression in keratinocytes, was inhibited by heparinoid treatment. The inhibitory effect of heparinoid on IL‐1β mRNA expression was also confirmed with living skin equivalents. Our results demonstrated that heparinoid suppresses the initiation of keratinocyte‐mediated skin inflammation.     

Cutaneous lupus erythematosus: The impact of self-amplifying innate and adaptive immune responses and future prospects of targeted therapies

Cutaneous lupus erythematosus (CLE) is a heterogeneous autoimmune disease encompassing a broad spectrum of skin conditions including localized plaques or widespread lesions, which may be accompanied by systemic involvement (systemic lupus erythematosus (SLE)). The disease is characterized by necroptotic keratinocytes and a cytotoxic immune cell infiltrate at the dermo-epidermal junction (DEJ), orchestrated by interferon (IFN)-regulated proinflammatory cytokines. Molecular analyses revealed a strong upregulation of innate and adaptive immune pathways in lesional skin including DNA-recognition pathways, chemokine signalling, antigen presentation and B- and T-cell activation, which are believed to interact in a complex self-amplifying network. Concerning adaptive immune signalling, particularly B cells are currently being studied as there is growing evidence for additional abilities besides autoantibody expression in skin autoimmunity. These detailed insights have paved the way for the development of drugs targeting crucial molecules of pathogenic immune cells and pathways. Moreover, they forwarded the understanding of distinct molecular mechanisms within CLE subtypes, which might enable a more mechanism-directed, stratified pharmacotherapy of LE skin lesions in the future.     

Tyrosine kinase 2 and interferon regulatory factor 5 polymorphisms are associated with discoid and subacute cutaneous lupus erythematosus

Please cite this paper as: Tyrosine kinase 2 and interferon regulatory factor 5 polymorphisms are associated with discoid and subacute cutaneous lupus erythematosus. Experimental Dermatology 2010; 19: 123–131. Abstract: Lupus erythematosus (LE) is a heterogeneous disease ranging from skin‐restricted manifestations to a progressive multisystem disease. The specific skin lesions include chronic cutaneous, subacute cutaneous and acute cutaneous LE. Both genetic and environmental factors are involved in the development of LE. However, reports on the genetic background of cutaneous lupus erythematosus (CLE) forms, namely discoid (DLE) and subacute cutaneous lupus erythematosus (SCLE), are sparse. We investigated whether the known systemic LE (SLE) susceptibility genes also predispose to CLE. Altogether, 219 Finnish patients with DLE or SCLE and 356 healthy controls were recruited. Single nucleotide polymorphisms tagging reported risk genes were genotyped. Tyrosine kinase 2 (TYK2) rs2304256 was associated with increased risk of DLE (P = 0.012, OR = 1.47, 95% CI = 1.01–1.98). Expression of TYK2 was demonstrated by immunohistochemistry in macrophage‐like cells and neutrophils and interferon regulatory factor 5 (IRF5) in macrophage‐ and fibroblast‐like cells of DLE, SCLE and SLE skin. IRF5 rs10954213 showed association with DLE (P = 0.017, OR = 1.40, 95% CI = 1.06–1.86) and SCLE (P = 0.022, OR = 1.87, 95% CI = 1.09–3.21). A haplotype of cytotoxic T‐lymphocyte‐associated protein 4 (CTLA4) showed association with DLE (P = 0.0065, OR = 2.51, 95% CI = 1.25–5.04). Our results show that the TYK2, IRF5 and CTLA4 genes previously associated with SLE also confer risk for DLE and SCLE, suggesting that different LE subphenotypes may share pathogenetic pathways.     

Dietary compound ellagic acid alleviates skin wrinkle and inflammation induced by UV‐B irradiation

Please cite this paper as: Dietary compound ellagic acid alleviates skin wrinkle and inflammation induced by UV‐B irradiation. Experimental Dermatology 2010; 19 : e182–e190. Abstract: Ellagic acid, a polyphenol compound present in berries and pomegranate, has received attention as an agent that may have potential bioactivities preventing chronic diseases. This study examined photoprotective effects of ellagic acid on collagen breakdown and inflammatory responses in UV (ultraviolet)‐B irradiated human skin cells and hairless mice. Ellagic acid attenuated the UV‐B‐induced toxicity of HaCaT keratinocytes and human dermal fibroblasts. Non‐toxic ellagic acid markedly prevented collagen degradation by blocking matrix metalloproteinase production in UV‐B‐exposed fibroblasts. Anti‐wrinkle activity of ellagic acid was further investigated in hairless mice exposed to UV‐B, in which it attenuated UV‐B‐triggered skin wrinkle formation and epidermal thickening. Topical application of 10 μmol/l ellagic acid diminished production of pro‐inflammatory cytokines IL‐1β and IL‐6, and blocked infiltration of inflammatory macrophages in the integuments of SKH‐1 hairless mice exposed to UV‐B for 8 weeks. In addition, this compound mitigated inflammatory intracellular cell adhesion molecule‐1 expression in UV‐B‐irradiated keratinocytes and photoaged mouse epidermis. These results demonstrate that ellagic acid prevented collagen destruction and inflammatory responses caused by UV‐B. Therefore, dietary and pharmacological interventions with berries rich in ellagic acid may be promising treatment strategies interrupting skin wrinkle and inflammation associated with chronic UV exposure leading to photoageing.     

Production and function of pigment epithelium‐derived factor in isolated skin keratinocytes

Pigment epithelium‐derived factor (PEDF) is a multifunctional factor with potent anti‐angiogenic activity that may play a role in skin homoeostasis and wound healing. Analysis of PEDF levels demonstrated that PEDF levels are high in normal skin but quite low in early wounds. As previous studies have suggested that keratinocytes can produce PEDF, we investigated how conditions that mimic those found at sites of injury influence PEDF production by keratinocytes in vitro. Both injury by mechanical disruption (scratch assay) and treatment of human keratinocytes with inflammatory cytokines (IL‐1β, IL‐6 and TNF‐α) inhibited PEDF expression. We next examined how PEDF affects keratinocyte functions that are important in tissue repair. Treatment of keratinocytes with exogenous PEDF enhanced keratinocyte adhesion, therefore impairing migration, while having no effect on cell proliferation. The results suggest that modulation of PEDF levels may play a pivotal role in skin homoeostasis and the response of keratinocytes to injury or inflammatory insults.     

Matrix metalloproteinases as mediators of tissue injury in different forms of cutaneous lupus erythematosus

Background Matrix metalloproteinases (MMPs) contribute to tissue destruction, regeneration, inflammation and apoptosis and several of them are upregulated by ultraviolet (UV) radiation in skin. Although some MMPs associate with organ manifestations of systemic lupus erythematosus (SLE), their role in cutaneous lupus erythematosus (LE) is elusive. Objectives Our aim was to evaluate the expression of MMPs in SLE, subacute cutaneous LE (SCLE) and discoid LE (DLE) skin lesions and their relation to apoptosis and epidermal changes. Methods Lesional skin biopsies from 20 patients with SLE, 20 with DLE and 17 with SCLE, and from UVA/UVB‐photoprovoked skin of healthy volunteers were immunostained using antibodies to multiple MMPs and tissue inhibitors of metalloproteinases (TIMPs). The TUNEL (terminal deoxynucleotidyl transferase‐mediated deoxyuridine triphosphate nick end labelling) method was used for detection of apoptosis. Results MMP‐3, ‐10, ‐19 and ‐26 were abundantly expressed by keratinocytes in SLE, DLE and SCLE skin samples. MMP‐7 was detected in keratinocytes in regions of oedema and vacuolization especially in SLE and SCLE, while MMP‐14 was only occasionally observed in keratinocytes. Photoprovocation did not induce MMP‐10 or ‐26 expression in skin of healthy volunteers. Epithelial TIMP‐1 expression was low while occasional positive fibroblasts were seen in the dermis. TIMP‐3 was abundantly expressed in the epidermis, endothelial cells and macrophages. Conclusions Different subtypes of cutaneous LE are fairly similar in their MMP expression profile. MMP‐3 and ‐10 mediate both epidermal changes and dermal tissue remodelling but are not present in lymphocytes. Low expression of TIMP‐1 suggests that lupus skin is characterized by proteolytic events, and targeted action using selective MMP inhibitors may reduce lupus‐induced damage in inflamed tissues.     

Ex vivo human skin and SZ95 sebocytes exhibit a homoeostatic interaction in a novel coculture contact model

The sebaceous gland displays key functions of the human skin, such as hormone synthesis in situ, antimicrobial activity and participation to inflammatory responses. Consequently, there is an emerging need of advanced in vitro models to study complex interactions between the sebaceous gland and the other skin compartments. Despite the evolution of both full‐skin organ culture and reconstructed three‐dimensional skin models, no satisfactory solutions have been provided for the integration of sebaceous glands and/or sebaceous gland cells in those models, probably due to their problematic maintenance both in vitro and ex vivo. We have developed a coculture model of explant skin in direct contact with immortalized SZ95 sebocytes, which resulted in overall improved structural integrity of the epidermis, higher percentage of proliferating basal epidermal cells and reduced apoptosis of differentiating keratinocytes after 6 days, as detected by Ki67 and TUNEL staining, respectively. Furthermore SZ95 sebocytes exhibited morphological and biochemical signs of normal differentiation and lipid accumulation, while interleukin‐6 expression in the supernatant of the cocultures was decreased in comparison with the control. The data provide evidence of a beneficial interaction between sebocytes and skin explants and provide the rationale for their integration in future three‐dimensional skin models.     

Characterization of the inflammatory infiltrate and expression of endothelial cell adhesion molecules in lupus erythematosus tumidus

Lupus erythematosus tumidus (LET) is a disease with characteristic clinical and histopathologic features that has not always been considered a subset of cutaneous lupus erythematosus (CLE). Although LET was first mentioned in the literature in 1930, it has rarely been documented, and immunohistochemical studies have never been performed. The aim of the present study was to characterize the inflammatory infiltrate and to analyze the expression of endothelial cell adhesion molecules in skin specimens from patients with LET and to compare the results with those from patients with other variants of CLE, such as discoid lupus erythematosus (DLE) and subacute cutaneous lupus erythematosus (SCLE). Cryostat sections of lesional skin specimens from ten patients with LET demonstrated an infiltrate composed of more than 75% CD4+, CD8+, and HLA-DR+ cells. Interestingly, CD45RO+ cells, in contrast to CD45RA+ cells, were the prevailing inflammatory cell population. Compared with skin specimens from patients with DLE and SCLE, the mean expression of CD4+ and CD8+ cells was higher (but not significantly so) in LET, and no differences were observed with the other three antibodies. Furthermore, in contrast to controls, intercellular adhesion molecule-1, vascular adhesion molecule-1, E-selectin, and P-selectin showed the same expression pattern in skin specimens from patients with DLE, SCLE, and LET. In conclusion, the inflammatory infiltrate of LET primarily consists of CD4+/CD8+ lymphocytes. Furthermore, expression of endothelial cell adhesion molecules was equally upregulated in LET compared with the expression in DLE and SCLE, suggesting a similar immunopathomechanism of these subtypes of CLE.     

皮肤型红斑狼疮皮损中SASPase的表达和意义

目的 探讨SASPase在皮肤型红斑狼疮皮损中的表达水平及其在发病机制中的意义.方法 无血清培养原代角质形成细胞,将提取的蛋白样品采用固相pH梯度双向凝胶电泳进行分离,应用ImageMaster 2D Platinum 5.0软件对图像进行匹配分析,选取差异表达蛋白质点,经基质辅助激光解吸附飞行时间质谱进行质谱鉴定.并通过免疫印迹验证表达水平.结果 成功培养角质形成细胞,获得重复性较好的双向电泳图谱,匹配点数在1200个左右,匹配率＞80％.鉴定SASPase在CLE皮损角质形成细胞表达升高,免疫印迹验证与双向电泳结果一致.结论 皮肤型红斑狼疮皮损的发生发展可能与SASPase的异常激活和过度表达有关.