Differential expression of mRNA for T-bet and GATA-3 transcription factors in peripheral blood mononuclear cells of patients with vitiligo

FOXO3 induces TUG1-mediated miR-375/GATA3 signaling axis to promote the survival of melanocytes in vitiligo

Vitiligo is characterized by the depletion of melanocytes due to the activation of CD8+ T cells. Taurine-upregulated gene 1 (TUG1), a long noncoding RNA, is involved in melanogenesis. This study aimed to explore the role and mechanism of TUG1 in vitiligo. RT-qPCR and western blot analyses demonstrated decreased TUG1 levels and increased miR-375 levels in patients with vitiligo. MTT and transwell assays indicated that TUG1 upregulation facilitated melanocyte survival and inhibited CD8+ T cell migration. Dual luciferase reporter and chromatin immunoprecipitation assays verified that Forkhead box O3 (FOXO3) directly interacted with the TUG1 promoter, leading to the positive regulation of TUG1 expression. In addition, FOXO3 promoted melanocyte survival by enhancing the transcription of TUG1. Luciferase reporter assay and RNA immunoprecipitation assay confirmed that TUG1 upregulated GATA binding protein 3 (GATA3) expression by targeting miR-375. TUG1 facilitated melanocyte survival by regulating the miR-375/GATA3 axis. In vitiligo, melanocyte survival is promoted by the induction of the TUG1-mediated miR-375/GATA3 axis by FOXO3, which offers new therapeutic targets for vitiligo treatment.

A Mendelian randomization study on the causal effects of circulating cytokines on the risk of vitiligo

Background

Accumulating evidence reveals an association between circulating cytokine levels and vitiligo. However, the causal association between circulating cytokine levels and vitiligo remains unrevealed.

Methods

We performed a two-sample Mendelian randomization (MR) analysis using a genome-wide association study of the 41 cytokines dataset, which was conducted with 3 Finnish cohorts (n = 8,293). Vitiligo data were acquired from strictly defined vitiligo data collected by FinnGenbiobank analysis, which included 207,613 European ancestors (131 vitiligo patients, 207,482 controls). The inverse-variance weighted (IVW) method, weighted median (WME), simple model, weighted model, and MR-Egger were used to determine the changes in vitiligo pathogenic cytokine taxa, followed by sensitivity analysis, including horizontal pleiotropy analysis. The MR Steiger test evaluated the strength of a causal association, and the leave-one-out method was used to assess the reliability of the results. The possibility of reverse causality was also investigated using a reverse MR study.

Results

We observed that rising IL-4 levels generated an enhanced probability of vitiligo in IVW (OR 2.72, 95%CI 1.19-6.22, p = 0.018). According to the results of the MR analysis, there were causal links between IL-4 and vitiligo. Results were steady after sensitivity and heterogeneity analyses.

Conclusion

Our research reveals that a genetically determined increased level of circulating IL-4 may be linked to a higher risk of developing vitiligo. The development of innovative treatment approaches (such as tofacitinib or dupilumab) that focus on blocking IL-4 as a novel way of preventing and treating vitiligo is significantly impacted by our findings.

GATA3 ameliorates melanocyte injuries in vitiligo through SIRT3‐mediated HMGB1 deacetylation

Vitiligo is a skin depigmentation disorder. GATA3 expression is downregulated in vitiligo patients, and its role and regulatory mechanism in vitiligo are unclear. GATA3 and HMGB1 levels were detected by qRT-PCR in peripheral blood cells of vitiligo patients and healthy controls, as well as H₂ O₂ -treated PIG1 cells. Their expression correlation was assessed by Pearson analysis. qRT-PCR, MTT assay, Ki67 immunostaining, flow cytometry, ELISA and Western blot were applied to determine GATA3 expression, cell survival, cell proliferation, cell apoptosis, melanin contents, and melanin-related protein expressions. The cellular distributions of HMGB1 and its deacetylation levels were detected by Western blot. The binding of GATA3 to SIRT3 promoter and effects on SIRT3 expression and HMGB1 deacetylation was determined by dual-luciferase assay, ChIP assay, and Western blot. GATA3 was decreased, and HMGB1 was increased in vitiligo. Pearson correlation assay showed that they were negatively correlated. H₂ O₂ significantly inhibited cell survival, proliferation, melanin secretion, and melanin-related protein expressions but remarkably increased cell apoptosis. GATA3 overexpression could distinctly reverse the effects of H₂ O₂ through decreasing HMGB1 expression and retained HMGB1 in nuclear due to the decreased HMGB1 acetylation. GATA3 bound to the SIRT3 and subsequently decreased H₂ O₂ -induced HMGB1 acetylation. Overexpressing HMGB1 or knockdown of SIRT3 could reverse the effects of GATA3 overexpression. GATA3 inhibited H₂ O₂ -induced injury in PIG1 cells and enhanced melanin secretion by SIRT3-regulated HMGB1 deacetylation, which might provide new evidence to treat vitiligo.

The role of cytokines and vitamin D in vitiligo pathogenesis

Vitiligo is a pigment-related disease with a global prevalence of 0.2% to 1.8% associated with considerable burden on quality of life. The treatment is still a challenge because of relapses and/or incomplete re-pigmentation. Although the exact cause is still unclear, its pathogenesis seems to be justifiable with the autoimmune theory, supported by the results of clinical research. In this narrative review, we aimed to summarize the evidence related to cytokines and vitiligo development. This review is consisted of English articles published in PubMed and Google Scholar concerning levels of inflammatory mediators, especially interleukins, in vitiligo patients over the last 20 years. References of relevant articles were also considered for review. Crucial role of dysregulated levels of interleukins and their synergistic function to each other, in the onset or progression of the disease is evident. The theory of autoimmune vitiligo is reinforced by the results of the studies in the literature, due to the association of pathogenesis with increased secretion of pro-inflammatory mediators and reduction of anti-inflammatory mediators. Decreased vitamin D levels may have a considerable role in vitiligo development by affecting Th1- and Th17-related immune responses. Cytokines play an important role in the pathogenesis or progression of the disease. Moreover, we believe that decreased vitamin D level has a considerable role in vitiligo development by affecting Th1- and Th17-related immune responses.

Diversified Stimuli-Induced Inflammatory Pathways Cause Skin Pigmentation

The production of melanin pigments by melanocytes and their quantity, quality, and distribution play a decisive role in determining human skin, eye, and hair color, and protect the skin from adverse effects of ultraviolet radiation (UVR) and oxidative stress from various environmental pollutants. Melanocytes reside in the basal layer of the interfollicular epidermis and are compensated by melanocyte stem cells in the follicular bulge area. Various stimuli such as eczema, microbial infection, ultraviolet light exposure, mechanical injury, and aging provoke skin inflammation. These acute or chronic inflammatory responses cause inflammatory cytokine production from epidermal keratinocytes as well as dermal fibroblasts and other cells, which in turn stimulate melanocytes, often resulting in skin pigmentation. It is confirmed by some recent studies that several interleukins (ILs) and other inflammatory mediators modulate the proliferation and differentiation of human epidermal melanocytes and also promote or inhibit expression of melanogenesis-related gene expression directly or indirectly, thereby participating in regulation of skin pigmentation. Understanding of mechanisms of skin pigmentation due to inflammation helps to elucidate the relationship between inflammation and skin pigmentation regulation and can guide development of new therapeutic pathways for treating pigmented dermatosis. This review covers the mechanistic aspects of skin pigmentation caused by inflammation.

Immune-modulatory effects of lenalidomide inhibited the progression of lesions in a vitiligo mouse model

Vitiligo, an autoimmune disorder, is associated with altered cytokine levels and T lymphocytes. Lenalidomide modulates immune system components by altering cytokine production and regulating T-cell stimulation. In this study, effect of lenalidomide was checked on the development of vitiligo lesions, level of various cytokines, and T lymphocytes in the mouse model. The vitiligo mouse model was developed by immunizing C57BL/6 mouse with anti-mouse tyrosine-related protein 2. Lenalidomide was orally given to mice daily, and the effect was observed on the development of vitiligo lesions. The level of T lymphocytes in blood was checked by flow cytometry. Serum cytokine levels were checked by enzyme-linked immunosorbent assay. Vitiligo lesions were found significantly smaller in lenalidomide-treated mice models. It significantly decreased the serum levels of IFN-γ, TNF-α, IL-1β, and IL-6 but elevated the levels of IL-4 and IL-10. It non-significantly elevated CD4⁺ /CD8⁺ T-cell ratio. Lenalidomide had an inhibitory effect on the development of vitiligo lesions in mice models by suppressing the serum level of pro-inflammatory cytokines and increasing anti-inflammatory cytokine levels. It modulated the immune response in vitiligo mice models toward an anti-inflammatory profile suggesting its use in the management of vitiligo.

Immune modulatory effects of lenalidomide on the cultured peripheral blood mononuclear cells from vitiligo patients

Vitiligo is a depigmentary disease in which epidermal melanocytes are lost. It is considered to be an autoimmune disease. Lenalidomide, an immunomodulatory drug is being employed in the treatment of various autoimmune and inflammatory disorders. In the present manuscript, the effect of lenalidomide on T cells and major cytokines in the cultured peripheral blood mononuclear cells (PBMCs) derived from vitiligo patients was checked. Eight patients with a clinical diagnosis of active vitiligo volunteered for the study. Blood was collected from them and PBMCs were isolated, cultured, and treated with lenalidomide. After 72 hours, PBMCs were harvested and checked for CD8⁺ and CD4⁺ T cells by flow cytometry. Further supernatant was collected and the levels of cytokines namely tumor necrosis factor-alpha (TNF-α), interferon-gamma (IFN-γ), interleukin-10 (IL-10), and interleukin-4 (IL-4) were checked using ELISA kits. Lenalidomide nonsignificantly decreased the level of CD8⁺ T cells but increased CD4⁺ T cells leading to increased CD4⁺ /CD8⁺ T cell ratio. It declined the level of pro-inflammatory cytokines, that is, TNF-α and IFN-γ whereas elevated anti-inflammatory cytokines, that is, IL-10 and IL-4, thus ultimately decreasing the ratio of pro-inflammatory to anti-inflammatory cytokines. Lenalidomide suppressed the proliferation of T lymphocytes and modulated the cytokines secretion toward an anti-inflammatory profile.

Expression analysis of PD-1 and Tim-3 immune checkpoint receptors in patients with vitiligo; positive association with disease activity

The contribution of immune checkpoint receptors in the immunopathogenesis of various autoimmune diseases has been addressed in previous reports. In this study,  the expression profile of T-cell immunoglobulin and mucin-domain containing-3 (Tim-3) and programmed cell death-1 (PD-1) checkpoint molecules was investigated in CD8⁺ T cells of Vitiligo patients. The association of Tim-3 and PD-1 expression with disease activity was also explored. The frequency of Tim-3⁺ /PD-1⁺ /CD8⁺ T cells in 30 patients with vitiligo and 30 sex- and age-matched controls was determined by flow cytometry. CD8⁺ T cells were then positively isolated by magnetic beads, and the mRNA expression of PD-1 and Tim-3 was determined by TaqMan-based real-time PCR. To measure the cytokines production, PBMCs were stimulated with PMA/ionomycin and concentrations of IL-4, IFN-γ and TNF-α were measured in culture supernatants by ELISA. Disease activity of patients with vitiligo was determined using the Vitiligo Area Severity Index. Patients with vitiligo have significantly shown more expression of Tim-3 and PD-1 on their CD8⁺ T cells compared with controls. Expression analysis of Tim-3 mRNA, but not PD-1, confirmed the results obtained from flow cytometry. While the production levels of TNF-α and IFN-γ were found higher by patients with vitiligo, IL-4 production was lower in patients compared with controls. A direct association was observed between the Tim-3 and PD-1 expression and also the production of pro-inflammatory cytokines with disease activity of patients with vitiligo. Our results indicate that Tim-3 and PD-1 are involved in immune dysregulation mechanisms of CD8⁺ T cells in vitiligo and may introduce as potential biomarkers for disease progression and targeted immunotherapy.

Roles of inflammation factors in melanogenesis (Review)

The occurrence of hyperpigmentation or hypopigmentation after inflammation is a common condition in dermatology and cosmetology. Since the exact mechanism of its occurrence is not yet known, prevention and treatment are troublesome. Previous studies have confirmed that α-melanocyte-stimulating hormone, stem cell factor and other factors can promote melanogenesis-related gene expression through the activation of signaling pathways. Recent studies have revealed that a variety of inflammatory mediators can also participate in the regulation of melanogenesis in melanocytes. In this review, we summarized that interleukin-18, interleukin-33, granulocyte-macrophage colony stimulating factor, interferon-γ, prostaglandin E2 have the effect of promoting melanogenesis, while interleukin-1, interleukin-4, interleukin-6, interleukin-17 and tumor necrosis factor can inhibit melanogenesis. Further studies have found that these inflammatory factors may activate or inhibit melanogenesis-related signaling pathways (such as protein kinase A and mitogen activated protein kinase) by binding to corresponding receptors, thereby promoting or inhibiting the expression of melanogenesis-related genes and regulating skin pigmentation processes. This suggests that the development of drugs or treatment methods from the perspective of regulating inflammation can provide new ideas and new targets for the treatment of pigmented dermatosis. This review outlines the current understanding of the inflammation factors' roles in melanogenesis.

A Network Pharmacology Approach to Uncover the Molecular Mechanisms of Herbal Formula Kang-Bai-Ling for Treatment of Vitiligo

Background

Kang-bai-ling (KBL), a Chinese patent medicine, has been demonstrated as an effective therapy for vitiligo in China. However, the pharmacological mechanisms of KBL have not been completely elucidated.

Methods

In this study, the potential multicomponent, multitarget, and multipathway mechanism of KBL against vitiligo was clarified by using network pharmacology-based strategy. In brief, potential targets of KBL were collected based on TCMSP databases, followed by network establishment concerning the interactions of potential targets of KBL with well-known therapeutic targets of vitiligo by using protein-protein interaction (PPI) data. As a result, key nodes with higher level of seven topological parameters, including “degree centrality (DC),” “betweenness centrality (BC),” “closeness centrality (CC),” “eigenvector centrality (EC),” “network centrality (NC),” and “local average connectivity (LAC)” were identified as the main targets in the network, followed by subsequent incorporation into the ClueGO for GO and KEGG signaling pathway enrichment analysis.

Results

In accordance with the topological importance, a total of 23 potential targets of KBL on vitiligo were identified as main hubs. Additionally, enrichment analysis suggested that targets of KBL on vitiligo were mainly clustered into multiple biological processes (associated with DNA translation, lymphocyte differentiation and activation, steroid biosynthesis, autoimmune and systemic inflammatory reaction, neuron apoptosis, and vitamin deficiency) and related pathways (TNF, JAK-STAT, ILs, TLRs, prolactin, and NF-κB), indicating the underlying mechanisms of KBL on vitiligo.

Conclusion

In this work, we successfully illuminated the “multicompounds, multitargets” therapeutic action of KBL on vitiligo by using network pharmacology. Moreover, our present outcomes might shed light on the further clinical application of KBL on vitiligo treatment.

The role of interleukins in vitiligo: a systematic review

Vitiligo is a disorder of the skin that causes depigmentation and asymptomatic macules whose exact cause is still unclear. Although its aetiology is not fully elucidated, the main theory of its pathomechanism is that it is associated with the autoimmune process. There is few summarized information about the role of inflammatory mediators, as interleukins, in vitiligo, so our aim was to present a systematic review of the role of interleukins in vitiligo, focusing on interleukins. In this review, we included all studies assessing interleukin levels in vitiligo patients conducted up to June 2017. Quality assessment of these studies was performed using the Newcastle-Ottawa Scale (NOS). The interleukins mainly involved were IL-2, IL-4, IL-6, IL-10 and IL-17. The studies highlight the crucial role of IL-17 in the onset and progression of the disease, and its synergistic action with IL-2, IL-6 and IL-33. Dysregulated levels of the interleukins were also correlated with the stage of disease, the affected skin surface area, and indicated as the main factor for lymphocyte infiltration found in depigmented regions. These findings illustrate the growing need for new therapies targeting vitiligo and further research into the role of interleukins as an area of particular interest.

Increased Levels of Serum Interleukin-17 in Patients with Hashimoto's Thyroiditis

BACKGROUND

CD4+ T-cells play important roles in the pathogenesis of Hashimoto's thyroiditis (HT). However, there is limited data about characteristics and function of the newly interleukin (IL)-17-producing T-helper cells in this common autoimmune thyroid disorder.

AIM

The purpose of this study was to assess the levels of T-helper 17-related cytokines in sera of patients with HT.

MATERIALS AND METHODS

Cytokine concentrations were measured in 48 patients with overt (n = 23) and subclinical hypothyroidism (25) and 35 healthy controls using enzyme-linked immunosorbent assay.

RESULTS

The serum levels of IL-17 were significantly higher in patients than controls (P = 0.001) while no differences were observed with regard to levels of IL-22 and IL-23 between patients and normal controls.

CONCLUSION

These results suggest that IL-17 could play some role in the pathogenesis of HT.

Enhanced Th1 and Th17 responses in peripheral blood in active non-segmental vitiligo

Accumulating studies have indicated that vitiligo, especially non-segmental vitiligo (NSV), is one kind of autoimmune diseases and CD4⁺ T cells play important roles in the pathogenesis. However, there have been very limited data on the detailed changes of each of the CD4⁺ T cell subsets in periphery in active NSV. To clarify this issue, we collected the peripheral blood mononuclear cells (PBMCs) from 30 patients with active NSV and 30 age- and sex-matched healthy controls. The percentages of circulating Th1, Th2, Th17 and Tregs were evaluated using flow cytometry and the expressions of their specific transcription factors T-bet, GATA3, RORγt and FOXP3 at mRNA level and protein levels were qualified by qPCR and flow cytometry, respectively. Meanwhile, the expression levels of IFN-γ, IL-4, TGF-β, and IL-17A in serum were measured. We found that in patients with NSV, the percentages and absolute numbers of circulating Th1 and Th17 were both significantly higher than those of healthy controls, while the percentages of Th2 and Tregs and absolute numbers showed no significant difference compared to healthy controls. Moreover, the ratios of Th1/Tregs and Th17/Tregs in circulation were both statistically elevated in active NSV. Similar results were got in qualification of their corresponding transcription factors at mRNA level and protein levels. Compared with healthy controls, the expression level of IL-17A was significantly increased in serum of patients with NSV, while the productions of IFN-γ, IL-4, TGF-β had no significant change. These data suggested that in circulating CD4⁺ T cell subsets, Th1 and Th17 played the major role in cellular immunity in the progression of vitiligo. The immune lever in circulation was inclined to effector CD4⁺ T cells not suppressor CD4⁺ T cells that may result in the loss of self-tolerance to melanocytes.

New-onset vitiligo and progression of pre-existing vitiligo during treatment with biological agents in chronic inflammatory diseases

BACKGROUND

The development of vitiligo during treatment with biological agents is an unusual event and only a few isolated cases have been reported.

OBJECTIVES

To describe the clinical characteristics and evolution of patients developing new-onset vitiligo following initiation of a biological agent for chronic inflammatory disease; and also to report the clinical course of pre-existing vitiligo under biological therapy.

METHODS

This nationwide multicentre, retrospective study, carried out between July 2013 and January 2015, describes the characteristics of a large series of 18 patients (psoriasis N = 8, inflammatory rheumatic diseases N = 8, ulcerative colitis N = 1, uveitis N = 1) who developed new-onset vitiligo while receiving a biological agent.

RESULTS

TNFα inhibitors were the most common biological agent involved (13/18) while anti-IL-12/23 and anti-IL-17 agents or abatacept were less common (4/18 and 1/18 respectively). Mean duration of biological agent exposure before vitiligo onset was 13.9 ± 16.5 months. Outcome was favourable for most patients (15/17) while maintaining the biological agent. Data were also collected for 18 patients (psoriasis N = 5, inflammatory rheumatic diseases N = 10, inflammatory bowel diseases N = 2, SAPHO N = 1) who had pre-existing vitiligo when treatment with a biological agent started (TNFα inhibitors N = 15, ustekinumab N = 1, rituximab N = 1, tocilizumab N = 1). Vitiligo progressed in seven patients and was stable or improved in eight cases.

CONCLUSION

Vitiligo may thus emerge and/or progress during treatment with various biological agents, mainly TNFα inhibitors and could be a new paradoxical skin reaction. De novo vitiligo displays a favourable outcome when maintaining the biological agent, whereas the prognosis seems worse in cases of pre-existing vitiligo.