Mechanisms of melanocyte death in vitiligo

The efficacy of combined phototherapy with topical therapy in vitiligo: a network meta-analysis

BACKGROUND

The comparative effects of phototherapy and topical therapy in patients with vitiligo remain unclear. A network meta-analysis (NMA) was conducted to assess which combination therapy was more beneficial for patients with vitiligo.

METHODS

This study analyzed phototherapy, including narrowband ultraviolet B (NB-UVB) and 308-nm excimer laser/light (EL) combined with topical therapies. Randomized controlled trials were sourced from PubMed, Embase, and Cochrane Library. Data analysis was based on a random-effects model, and surface under the cumulative ranking (SUCRA) curves employed to assess the efficacy of the interventions.

RESULTS

This NMA included 27 trials, with a total of 2417 lesions (patches). According to the results of the SUCRA, for achieving ≥50% repigmentation, the top three combination therapies were phototherapy combined with antioxidants (SUCRA 87.7), corticosteroids (SUCRA 69.6), and calcineurin inhibitors (SUCRA 52.5), while for ≥75% repigmentation, the leading therapies were phototherapy combined with antioxidants (SUCRA 89.0), calcineurin inhibitors (SUCRA 70.3), and fractional CO2 laser (SUCRA 63.6).

CONCLUSIONS

This meta-analysis suggests that combining phototherapy with topical antioxidants, corticosteroids, or calcineurin inhibitors may offer superior outcomes for vitiligo patients. This study provides a reference for clinicians to develop personalized treatment plans for patients with vitiligo.

Neurological Mechanisms Exploration and Therapeutic Targets in Segmental Vitiligo Accompanied by White Hair

Vitiligo is the most common skin depigmentation disease, affecting 0.1%-2% of people in the world. 3.5%-20.5% of segmental patients account for the total number of vitiligo patients. It has been clinically observed that segmental vitiligo patients are more likely to generate white hair, which may be related to neuroendocrine factors. The color of human skin and hair is affected by the number and functional status of melanocytes. Vitiligo affects patients' physical and mental health due to the shame it causes from the white patches and hair. This article reviews the underlying mechanisms of segmental vitiligo with white hair based on skin and hair follicle melanocytes. The article attempts to propose possible targets for the treatment of this disease.

Beyond skin deep: exploring the complex molecular mechanisms and holistic management strategies of vitiligo

Vitiligo is a multifactorial skin disorder characterized by the progressive loss of pigmentation due to the destruction of melanocytes, affecting 0.5-2% of the global population. This condition not only impacts physical appearance but also has profound psychosocial effects on patients. In this review, various aspects of vitiligo are explored, including its clinical forms, epidemiology, and underlying mechanisms. Advances in research have identified key molecular pathways, such as Wnt/β-Catenin, JAK-STAT, and AhR signaling, which are essential for melanocyte survival and immune regulation. These pathways provide valuable insights into the disease's progression and potential treatment targets. Furthermore, the role of microbial imbalances in the gut and skin microbiomes, stress-related factors, and nutritional deficiencies in influencing the onset and progression of vitiligo is investigated. The potential of herbal treatments to stimulate repigmentation is also discussed. By presenting a comprehensive overview, this review aims to deepen the understanding of vitiligo's complex pathology and foster the development of effective therapeutic strategies to enhance patient care.

Implication of Immunobiological Function of Melanocytes in Dermatology

Melanocytes are essential for regulating pigmentation and providing photoprotection in human skin. Originating from neural crest cells, these cells migrate to the basal layer of the epidermis and hair follicles during embryogenesis. Melanosomes, the specialized, membrane-bound organelles are essential for melanin synthesis. Beyond their role in pigmentation, melanocytes exhibit complex immune functions, expressing a variety of immune-related markers and receptors, such as pattern recognition receptors (PRRs), major histocompatibility complex class II (MHC-II) molecules, CD40, intercellular adhesion molecule 1 (ICAM-1), and programmed death-ligand 1 (PD-L1). These receptors allow melanocytes to detect environmental signals and engage in the innate immune response. Furthermore, melanocytes release various immunomodulatory substances, including proinflammatory cytokines, chemokines, and damage-associated molecular patterns (DAMPs), contributing to immune regulation. The immune functions of melanocytes are significantly influenced by external factors such as ultraviolet radiation (UVR), the microbiome, and oxidative stress. In different skin diseases, these immune functions may vary. For example, vitiligo, a common hypopigmentary disorder, is primarily driven by an autoimmune response targeting melanocytes, giving rise to depigmentation and the appearance of white patches. In contrast, melanoma, a form of skin cancer that arises from melanocytes, is closely linked to UV exposure. This review highlights the diverse immunobiological functions of melanocytes and their implications in dermatology.

Vitiligo associated with type 2 immune inhibitors: FAERS analysis and literature review

With the widespread use of type 2 immune response inhibitors (IRIs), there is growing concern about their association with the occurrence of vitiligo. This study aimed to comprehensively search for cases of vitiligo associated with type 2 IRIs in the US Food and Drug Administration Adverse Event Reporting System (FAERS). We retrieved the clinical characteristics of cases from January 2004 to September 2024 from the FAERS database. Disproportionality and Bayesian analyses were conducted to detect signals for vitiligo associated with type 2 IRIs. A total of 86 cases of vitiligo were identified in association with these inhibitors. The mean onset time was 326 days. Vitiligo associated with dupilumab was the most common (81.4%), with the highest reporting odds ratio (2.67, 95% confidence interval  2.11-3.4), proportional reporting ratio (2.67, χ2 = 70.59), information component (1.38, [IC025 = 1.09), and empirical Bayes geometric mean (2.61, EBGM05 = 2.14). The link between vitiligo and type 2 IRIs underscores the need for continued pharmacovigilance to better understand these drugs and the incidence of related conditions.

An investigation into the mechanism for Kaempferol improving melanocyte death based on network Pharmacology and experimental verification

Melanocyte (MC) death represents the basic pathological change of vitiligo. Kaempferol (Kae) is one of the main active ingredients of Tribulus terrestris, which is a commonly used Chinese medicine in the treatment of vitiligo. However, it remains unclear whether Kae can improve MC death, and hence relevant mechanisms need to be further explored. Therefore, we aimed to investigate the effect of Kae on MC death and relevant mechanisms. The targets of Kae and the differential genes of vitiligo were screened based on different databases. Besides, the protein-protein interaction (PPI) network of the common target of Kae and vitiligo was constructed to further identify the "keycluster" genes of the drug-disease interaction (DDI) network. In addition, the enrichment analysis based on Gene Ontology (GO), Disease Ontology (DO), and Kyoto Encyclopedia of Genes and Genomes (KEGG) was performed on the "keycluster" genes. Based on the network pharmacological results, it was found that Kae may ameliorate MC death through the ferroptosis pathway. Hence, the ferroptosis model of human primary epidermal melanocyte 1 (HEM-1) was induced by RAS-selective lethal 3 (RSL3) and then co-cultured with Kae. Moreover, the role of Kae in MC ferroptosis was investigated by detecting the changes in mitochondrial morphology and functions, the levels of reactive oxygen species (ROS) and iron ions, the protein expression of glutathione peroxidase 4 (GPX4), and antioxidant activities. Finally, si-GPX4 was used to silence the ferroptosis core protein GPX4 to re-examine the above indicators, thus verifying relevant mechanisms. The network pharmacology results showed that Kae was responsive to oxidative stress and ROS. The treatment of vitiligo by Kae mainly involved pigmentation, melanin metabolic processes, and such signaling pathways as melanogenesis, ferroptosis, and tyrosine metabolism. The in vitro experiment results indicated that Kae can effectively improve RSL3-induced HEM-1 ferroptosis, including alleviating mitochondrial damage, decreasing the level of ROS and iron ions, and up-regulating the expression of GPX4 and antioxidants. After silencing GPX4, the protective effect of Kae against HEM-1 ferroptosis was attenuated. Our study concluded that Kae can reduce RSL3-induced ferroptosis in HEM-1, and its mechanism is related to the regulation of the expression of the ferroptosis pathway protein GPX4. These findings are expected to provide novel insights into the treatment of vitiligo.

Cytosolic mtDNA-cGAS-STING axis mediates melanocytes pyroptosis to promote CD8+ T-cell activation in vitiligo

BACKGROUND

The cGAS-STING axis, a DNA sensor pathway, has recently emerged as a key hub in sensing stress signals and initiating the immune cascade in several diseases. However, its role in the pathogenesis of vitiligo remains unclear.

OBJECTIVE

To explore the pathogenic role of the cGAS-STING axis in linking oxidative stress and CD8+ T-cell-mediated anti-melanocytic immunity in vitiligo.

METHODS

The expression status of the cGAS-STING axis and cytosolic mtDNA were evaluated in the oxidatively stressed epidermal cells and vitiligo perilesional skin, respectively. Then, we investigated the activation of cGAS-STING axis in mtDNA-treated melanocytes, and the influence of cGAS or STING silencing on mtDNA-induced melanocytes pyroptosis. Finally, the paracrine effects of melanocytes pyroptosis on CD8+ T cell activation were explored.

RESULTS

We initially demonstrated that the cGAS-STING axis in melanocytes was highly susceptible to oxidative stress and activated in the vitiliginous melanocytes of perilesional skin, accompanied by enhanced cytosolic mtDNA accumulation. Our mechanistic in vitro experiments confirmed that oxidative stress-induced mitochondrial damage in epidermal cells led to cytosolic mtDNA accumulation, which served as a trigger in activating the cGAS-STING axis in melanocytes. Furthermore, the cytosolic mtDNA-cGAS-STING axis was verified to mediate melanocytes pyroptosis. More importantly, we found that IL-1β and IL-18 produced by pyroptotic melanocytes promoted the activation of CD8+ T cells from patients with vitiligo.

CONCLUSION

The present study confirmed that the cytosolic mtDNA-cGAS-STING axis of melanocytes played an important role in oxidative stress-triggered CD8+ T-cell response, providing novel insights into mechanisms underlying vitiligo onset.

Concurrent management of vitiligo and acquired disorders of hyperpigmentation: a comprehensive literature review and current practice gaps

Few studies discuss the co-management of vitiligo and acquired hyperpigmentation disorders (AHD) such as melasma, erythema dyschromicum perstans, post-inflammatory hyperpigmentation, drug-induced hyperpigmentation, and lichen planus pigmentosus. This review discusses clinical studies examining co-management strategies and identifies current practice gaps. Dermatology Life Quality Index scores are higher in individuals with vitiligo or melasma. It is plausible that populations experiencing both conditions may exhibit worsened psychological outcomes because of stigmas and perceived social beauty standards. Standard treatments for vitiligo aim to increase pigmentation, while AHD treatments target decreasing pigmentation, causing potential worsening of contrast between multiple skin tones for patients experiencing both disorders. Tretinoin may prevent narrowband ultraviolet B (NBUVB)-induced hyperpigmentation in patients with vitiligo without altering treatment response and is also beneficial for managing AHD. In addition, the use of oral tranexamic acid to treat melasma does not diminish the response to NBUVB phototherapy. Platelet-rich plasma (PRP) injections and oral Polypodium leucotomos extract may also be beneficial for comanaging vitiligo and AHD. However, practice guidelines are needed to optimize care for this patient population.

Candidate approaches for predicting vitiligo recurrence: an effective model and biomarkers

Background

Vitiligo is a challenging chronic condition with unpredictable disease course and high propensity for relapse post-treatment. Recent studies have reported the biomarkers for disease activity, severity, and therapeutic response of vitiligo, yet very few have investigated cytokines as predictive biomarkers for disease recurrence in vitiligo. This study aims to explore cytokines that serve as biomarkers for disease recurrence and extend research on factors related to the disease's activity.

Methods

92 patients and 40 healthy controls were recruited at the Air Force Medical Center from September 20, 2023, to November 30, 2023. Ultrasensitive multiplex cytokine array was used to measure plasma concentrations of cytokines, including IFN-γ, CXCL9, CXCL10, CXCL11, IL-6, and IL-15.

Results

IFN-γ, CXCL9, CXCL10, CXCL11, IL-6, and IL-15 were expressed at higher levels in the circulation of patients with both segmental and non-segmental vitiligo compared to healthy controls (p < 0.001). There were no significant differences in these cytokine levels between the two types of vitiligo. CXCL9 was associated with the activity of vitiligo (p = 0.027). Correlation analysis showed a positive relationship between IFN-γ, CXCL9, CXCL10, CXCL11, IL-6, and IL-15 in the plasma of patients with recurrent vitiligo. The expression of IFN-γ, CXCL9, CXCL10, CXCL11, and IL-6 was significantly higher in recurrent vitiligo than in cases of persistent stable vitiligo (p = 0.001, p = 0.003, p < 0.001, p = 0.002, p = 0.026, respectively), with ROC analysis demonstrating their predictive capability for vitiligo recurrence, with AUC values of 0.806, 0.773, 0.896, 0.785, and 0.709, respectively. Multivariate logistic regression model showed IFN-γ is an independent predictor for vitiligo recurrence [OR (95%CI) =1.051 (1.012~1.116)], with a prediction accuracy of 90.5% (38/42) on the training dataset and 88.9% (16/18) on the testing dataset.

Conclusion

Plasma IFN-γ, CXCL9, CXCL10, CXCL11 and IL-6 might be potential biomarkers for vitiligo recurrence, with CXCL9 also associated with disease activity. Additionally, multivariate logistic regression model demonstrated that IFN-γ is an independent predictor of vitiligo recurrence and the model could be a candidate approach for predicting vitiligo recurrence.

Biomimetic polydopamine loaded with janus kinase inhibitor for synergistic vitiligo therapy via hydrogel microneedles

BACKGROUND

Both oxidative stress and autoimmune responses play crucial roles in the development of vitiligo. Under oxidative stress, the apoptotic melanocytes expose self-antigens and release high mobility group box 1 (HMGB1), triggering autoimmune activation and recruiting CD8+ T cells. This process further leads to the destruction of melanocytes, resulting in the lack of melanin granules. Additionally, the accumulated CD8+ T cells release interferon-γ (IFN-γ) to activate janus kinase-signal transducer and activator of transcription (JAK-STAT) pathway in keratinocytes. Both oxidative stress and IFN-γ-JAK-STAT activation induce keratinocytes to express and release T cell chemotactic factors, exacerbating the process of vitiligo. Reducing the accumulation of CD8+ T cells by safeguarding melanocytes and keratinocytes from oxidative stress may be contemplated as a promising approach for vitiligo therapy.

RESULTS

In this study, we introduce a novel therapeutic agent called PDA-JAKi, which is capable of both eliminating oxidative stress and inhibiting T cell activation. Specifically, we have incorporated the janus kinase inhibitor (JAKi) tofacitinib into antioxidant polydopamine (PDA) nanoparticles, resulting in the formation of uniform PDA-JAKi nanodrug. PDA-JAKi effectively mitigates oxidative stress-induced apoptosis in melanocytes, reducing the antigen presentation and release of HMGB1. In addition, PDA-JAKi simultaneously attenuates oxidative stress and blocks the IFN-γ-JAK-STAT pathway to reduce the expression of C-X-C motif chemokine ligand 9/10/16 (CXCL9/10/16) in keratinocytes. We precisely deliver this therapeutic agent to the dermis using microneedle (MN) patches, aiming to enhance therapeutic efficacy compared to traditional drug administration methods. After PDA-JAKi MN treatment, the symptoms of vitiligo in mice are alleviated, and the affected areas regain pigmentation. Enhancements have been observed in the dermal thickness, the numbers of melanocytes and the content of melanin within the treated skin area. Moreover, there is a notable reduction in reactive oxygen species (ROS) level. Concurrently, substantial decreases were noted in CD8+ T cell infiltration, as well as the levels of IFN-γ and chemotactic factors CXCL9/10/16.

CONCLUSIONS

In summary, PDA-JAKi MN patches emerge as a promising therapeutic agent for vitiligo treatment.

Preparation of Ethosome Gel with Total Flavonoids from Vernonia anthelmintica (L.) Willd. for the Treatment of Vitiligo

Vernonia anthelmintica (L.) Willd. is a traditional medicinal herb in Chinese medicine, extensively used by various ethnic groups due to the numerous advantages derived from its total flavonoids. These benefits encompass anti-inflammatory and antioxidant effects, and the promotion of melanin production, showcasing its significant efficacy in addressing vitiligo. To improve transdermal absorption and enhance the antioxidant effectiveness of the treatment, ethosome containing total flavonoids were prepared utilizing the ultrasound injection technique. The resulting ethosome was then carefully mixed with 0.7% Carbomer 934 gel in equal parts, yielding a gel concentration of 0.302 mg/g. This formulation produced small, consistent ethosome that exhibited high encapsulation efficiency and notable stability. In vitro analyses demonstrated sustained release characteristics of the gel and considerable therapeutic effectiveness against vitiligo resulting from hydroquinone exposure. Histological examinations performed through hematoxylin and eosin (H&E) staining of mouse skin revealed increased melanin production and increased activities of tyrosinase (TYR), cholinesterase (CHE), and mouse monoamine oxidase (MAO), while levels of superoxide dismutase (SOD) and malondialdehyde (MDA) were reduced. These findings underscore the promising effectiveness of this treatment strategy and validate the efficacy of the dosage form.

Integrative genetics and multiomics analysis reveal mechanisms and therapeutic targets in vitiligo highlighting JAK STAT pathway regulation of CTSS

Vitiligo is a complex autoimmune disease characterized by the loss of melanocytes, leading to skin depigmentation. Despite advances in understanding its genetic and molecular basis, the precise mechanisms driving vitiligo remain elusive. Integrating multiple layers of omics data can provide a comprehensive view of disease pathogenesis and identify potential therapeutic targets. The study aims to delineate the genetic and molecular mechanisms of vitiligo pathogenesis using an integrative multiomics strategy. We focus on exploring the regulatory influence of the JAK/STAT pathway on Cathepsin S, a potential therapeutic target in vitiligo. Our GWAS-meta analysis pinpointed five druggable genes: ERBB3, RHOH, CDK10, MC1R, and NDUFAF3, and underwent drug target exploration and molecular docking. SMR analysis linked CTSS, CTSH, STX8, KIR2DL3, and GRHPR to vitiligo through pQTL and eQTL associations. Microarray and single-cell RNA-seq data showed differential expression of CTSS and STAT1/3 in vitiligo patients' blood and skin lesions. Our study offers novel perspectives on vitiligo's genetic and molecular basis, highlighting the JAK/STAT pathway's role in regulating CTSS for antigen processing in melanocytes. Further research is needed to confirm these results and assess the therapeutic potential of CTSS and related genes.

Correlation Between the Koebner Phenomenon and Clinical Features in Vitiligo

Purpose

To investigate the correlation between the presence of the Koebner phenomenon (KP) and clinical features of patients with vitiligo.

Patients and Methods

The clinical characteristic data, including age, age of onset, disease duration, gender, clinical stage, clinical type, family history, and comorbid immune-related diseases, of 1472 patients with/without KP were analyzed with SPSS 17.0 software.

Results

Of the 1472 patients, 290 (19.70%) were positive for KP. The clinical course (6.95 vs 5.62, P = 0.015), percentage of patients with progressive stage (78.97% vs 70.05%, P = 0.002), the acrofacial type (4.49% vs 1.69%, P = 0.004), comorbid immune-related diseases (28.29% vs 19.04%, P = 0.001) and lesion area ≥2% (47.24% vs 38.24%, P = 0.005) in KP-positive group were significantly greater than those in KP-negative group. Binary logistic regression analysis found that progressive stage (P = 0.003, OR = 1.60, 95% confidence interval (CI): 1.17-2.18), area of skin lesion ≥2% (P = 0.008, OR = 1.44, 95% CI: 1.10-1.88) and comorbid immune-related diseases (P = 0.001, OR = 1.63, 95% CI: 1.21-2.20) were significantly associated with KP.

Conclusion

The presence of KP in patients with vitiligo is associated with clinical progression, the acrofacial type, comorbid immune-related disease and a larger lesion area. This study suggested the presence of KP may be an indicator of disease activity and aggression, and underlay its importance in the management of disease.

Pathogenesis and regenerative therapy in vitiligo and alopecia areata: focus on hair follicle

Vitiligo is an autoimmune disease characterized by the loss of functional melanocytes in the hair follicles and epidermis, leading to white patches on the skin and mucous membranes. Alopecia areata (AA) is a common immune-mediated condition in which autoimmune attack on hair follicles cause non-scarring hair loss. Both diseases significantly impact patients's physical and mental health. Hair follicles, dynamic mini-organs, house diverse stem cell populations that form hair structures. Melanocyte stem cell (McSCs) and hair follicle stem cells (HFSC) located in the hair follicle bulge contribute to follicular structures during each anagen phase of the hair cycle, synchronizing periodic activities to impact color to the hair. Hair follicle dysfunction may contribute to hair loss and could potentially interfere with repigmentation efforts in vitiligo lesions. This article reviews the role of hair follicles in the pathogenesis, clinical manifestations, and therapeutic options for vitiligo and AA, aiming to deepen clinicians' understanding of follicular involvement in these diseases and explore potential treatment avenues.

Bioinformatic analysis of ferroptosis related biomarkers and potential therapeutic targets in vitiligo

Vitiligo is a complex autoimmune skin disorder characterized by depigmentation and immune dysregulation. To elucidate the role of ferroptosis-related genes (FRGs) in vitiligo, we conducted a comprehensive analysis of gene expression data from the GSE53146 and GSE65127 datasets obtained from the GEO database. We identified 31 differentially expressed FRGs (DE-FRGs), with 21 genes upregulated and 10 downregulated. Functional enrichment analysis revealed that these DE-FRGs are significantly involved in oxidative stress, immune regulation, and vitiligo-associated signaling pathways. Utilizing machine learning approaches, including LASSO and SVM-RFE, we identified four key marker genes (ALOX5, SNCA, SLC1A4, and IL33) with strong diagnostic potential. Immune landscape analysis demonstrated that these marker genes influence immune cell composition, particularly showing correlations with CD8 + T cells and regulatory T cells. Furthermore, drug-gene interaction analysis proposed potential therapeutic targets, while ceRNA network analysis uncovered intricate regulatory relationships involving miRNAs and lncRNAs. Collectively, our findings provide novel insights into the molecular mechanisms underpinning vitiligo and suggest new avenues for diagnostic and therapeutic development.

Comparison of various excimer laser (EL) combination therapies for vitiligo: a systematic review and network meta-analysis

AIM

This study aimed to compare the efficacy and safety of excimer laser (EL)-based combination regimens in improving repigmentation.

METHODS

A comprehensive search was conducted in PubMed, Web of Science, Cochrane Library, and Embase on July 1, 2023, to include randomized controlled trials of EL combination treatments for vitiligo that met the criteria. The primary outcome measure was a repigmentation rate ≥ 75%, and the secondary outcome measures were a repigmentation rate of ≤ 25% and adverse events.

RESULTS

Eleven studies involving 348 patients were included. Network Meta-Analysis showed that EL combined with antioxidants (SUCRA = 98.8%), EL combined with calcipotriol (SUCRA = 59.8%) and EL combined with tacalcitol (SUCRA = 59.6%) were the three optimal interventions achieving repigmentation rates ≥ 75%. EL alone (SUCRA = 77.6%), EL combined with tacalcitol (SUCRA = 61.7%) and EL combined with antioxidants (SUCRA = 57.2%) were the three interventions with the highest rates of treatment failure. Adverse events in all groups mainly included erythema, burning sensation and hyperpigmentation. Based on the results of the current study, EL combination therapies were safe with mild adverse events.

CONCLUSION

EL combined with antioxidants was the preferred regimen for vitiligo, whereas EL alone was the regimen with the highest rate of treatment failure in vitiligo.

The Effect of Monobenzone Cream on Oxidative Stress and Its Relationship With Serum Levels of IL-1β and IL-18 in Vitiligo Patients

BACKGROUND

Monobenzyl ether hydroquinone (MEBHQ) is a cream that promotes the spread and evenness of skin patches in vitiligo. Our aim was to investigate the oxidative and inflammatory effects of this cream on vitiligo patients consuming MEBHQ.

METHODS

A case-control study was conducted with three groups of 30 people from the control group, vitiligo patients before and after treatment. The percentage of vitiligo spots was determined by a specialist doctor. The levels of biochemical factors, oxidative stress profile and inflammatory factors were measured by enzymatic, colorimetric and ELISA methods, respectively.

RESULTS

Vitiligo patients showed a high level of inflammation and oxidative stress compared to healthy people. Although after 3 months of using MBEHQ cream, the percentage of skin spots in vitiligo patients increased from an average of 63%-91% and the skin color became almost uniform, but it still increased the level of oxidative stress and inflammation in these patients. Although the level of oxidative stress increased significantly in these patients, there was no significant increase in the level of malondialdehyde. The lack of significant differences in the levels of biochemical factors between healthy people and vitiligo patients before and after using the treatment shows the absence of side effects.

CONCLUSION

The use of MBEHQ increased the size of skin spots and uneven skin color in vitiligo patients. Although MBEHQ did not show side effects such as diabetes, liver and kidney diseases, it increased the levels of oxidative stress and inflammatory cytokines, which needs further study.

Mechanistic Insights into the Stimulatory Effect of Melanogenesis of 4-Methylcoumarin Derivatives in B16F10 Melanoma Cells

Vitiligo is a skin condition characterized by the loss of pigment, resulting in white patches on various parts of the body. It occurs when melanocytes, the cells that are responsible for producing skin pigment, are destroyed or stop functioning. This study aimed to investigate the melanogenic potential of various 4-methylcoumarin (4MC) derivatives, including 6-methoxy-4-methylcoumarin (6M-4MC), 7-methoxy-4-methylcoumarin (7M-4MC), 7-amino-4-methylcoumarin (7A-4MC), 6,7-dihydroxy-4-methylcoumarin (6,7DH-4MC), 7,8-dihydroxy-4-methylcoumarin (7,8DH-4MC), and 6,7-dimethoxy-4-methylcoumarin (6,7DM-4MC), in B16F10 melanoma cells. Our findings revealed that, while 4MC, 7A-4MC, 6,7DH-4MC, and 7,8DH-4MC did not exhibit any effect on melanin production, significant stimulation of melanogenesis was observed with 6M-4MC, 7M-4MC, and 6,7DM-4MC, with 6M-4MC demonstrating the most pronounced effect. 6M-4MC significantly stimulated melanin production and tyrosinase activity in a concentration-dependent manner in B16F10 cells. A Western blot analysis revealed that 6M-4MC increased the expression levels of microphthalmia-associated transcription factor (MITF), tyrosinase, tyrosinase-related protein-1 (TRP-1), and tyrosinase-related protein-2 (TRP-2). Further mechanistic studies showed that 6M-4MC inhibited extracellular signal-regulated kinase (ERK) and protein kinase B (AKT), which led to the upregulation of MITF and TRP proteins and subsequent activation of melanin synthesis. Additionally, 6M-4MC activated GSK3β phosphorylation, reduced β-catenin phosphorylation, and stimulated melanogenesis via the GSK3β/β-catenin pathway. Moreover, a primary skin irritation test was conducted on the upper backs of 32 healthy female volunteers to assess the potential irritation or sensitization from 6M-4MC when applied topically at concentrations of 50 µM and 100 µM. The test results showed no adverse effects on the skin. Collectively, these findings suggest that 6M-4MC may be a promising pigmentation stimulator for use in cosmetics and in the medical treatment of hypopigmentation disorders, particularly in the treatment of skin conditions such as vitiligo.

Exploring the Role of Adipose Tissue Dysregulation in Vitiligo Pathogenesis: A Body Composition Analysis

Vitiligo is a commonly acquired pigmentary disease characterized by the progressive destruction of melanocytes. The role of adipose tissue in vitiligo remains unclear. To investigate the role of adipose tissue in the pathogenesis of vitiligo, 50 patients newly diagnosed with vitiligo and 40 age- and sex-matched healthy controls were enrolled, and fat mass and distribution using dual-energy X-ray absorptiometry (DXA) and serum adipokine levels using enzyme-linked immunosorbent assay were assessed. The trunk and whole-body fat mass and the trunk/limb fat mass ratio were significantly higher in patients with vitiligo. Higher leptin and resistin levels and lower adiponectin levels were observed. Positive correlation of the trunk fat mass index with vitiligo area scoring index scores (r = 0.38, p = 0.0071) was found. Additionally, plasma adiponectin levels were negatively correlated with vitiligo disease activity scores (r = -0.307, p < 0.05). Receiver operating characteristic curve analysis showed that the percentage of limb lean tissue mass, trunk/limb fat mass ratio, and serum adipokine levels achieved a high area under the curve score for distinguishing patients with vitiligo from healthy controls. In conclusion, the incidence of central obesity and adipokine dysregulation was higher in patients with vitiligo. The potential role of adipose tissue in the pathogenesis of vitiligo should be emphasized.

Exploration of the mechanism of Qinglongyi-Buguzhi drug pair in treating vitiligo based on network pharmacology, molecular docking and experimental verification

ETHNOPHARMACOLOGICAL RELEVANCE

The Qinglongyi-Buguzhi herbal pair (QB) is one of commonly used herbal combinations for treating vitiligo in traditional Chinese medicine, consisting of the exocarp of the immature fruit of Juglans regia L. or Juglans mandshurica Maxim., and dried, mature fruit of Psoralea corylifolia L. However, the active components and potential mechanisms of QB in the treatment of vitiligo are still unclear.

AIM OF THE STUDY

The purpose of this study is to clarify the effects and mechanisms of QB on vitiligo treatment through integration of network pharmacology and empirical examinations.

MATERIALS AND METHODS

The active components and targets of QB as well as the targets linked to vitiligo were obtained from network databases. Visualization networks were constructed with Cytoscape 3.9.1. GO and KEGG enrichment analysis were conducted to investigate the possible mechanism. Molecular docking was employed to evaluate the binding affinities between the primary active ingredients of QB and essential targets of the PI3K/Akt/Nrf2 pathway. In vivo and in vitro experiments were carried out to confirm the results of network pharmacology.

RESULTS

We evaluated 44 active compounds and 602 genes from QB, and 107 of these genes linked to vitiligo. GO analysis suggested QB might lessen vitiligo by regulating oxidative stress. KEGG pathway analysis indicated the PI3K/Akt pathway may be crucial for treating vitiligo. Molecular docking results demonstrated the key active ingredients of QB had good binding activity with the major targets in the PI3K/Akt/Nrf2 pathway. In vivo, QB significantly ameliorated vitiligo model mouse's skin pathologies by reducing ROS, elevating CAT and SOD levels. Western blot showed that QB increased the phosphorylation of PI3K and Akt and the expressions of Nrf2 and HO-1 in the skin. In vitro, QB reversed H2O2-induced oxidative injury of melanocytes, enhanced cell survival rate, reduced ROS level, upregulated SOD and CAT activities, and raised the content of melanin. Moreover, QB upregulated the expression levels of Akt, Nrf2, HO-1 mRNA, Akt phosphorylation, HO-1, and nuclear Nrf2 proteins, and also encouraged the nuclear translocation of Nrf2. However, LY294002 treatment significantly reversed the regulatory effect of QB on oxidative damage of melanocytes.

CONCLUSIONS

This study revealed that the therapeutic effect of QB on vitiligo was achieved through multiple components, targets and pathways. Experimental investigation demonstrated that QB could improve vitiligo via reducing oxidative stress, which was probably accomplished by activating the PI3K/Akt/Nrf2 signaling pathway.

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.

Targeting Periplakin of Novel Benzenesulfonamides as Highly Selective Agonists for the Treatment of Vitiligo

Vitiligo is the most common cause of depigmentation worldwide, with immunosuppressive treatments often being inefficient and prone to recurrence, making it essential to identify new therapeutic targets. Periplakin (PPL) has been identified and confirmed as a key factor in vitiligo-related depigmentation. Based on this, a series of selective PPL agonists, specifically benzenesulfonamides, have been developed. Among these, compound I-3 exhibits superior efficacy compared to ruxolitinib, the only FDA-approved treatment for vitiligo. I-3 has been shown to increase cAMP levels by regulating PPL, which enhances MITF expression, a key transcription factor in melanin biosynthesis. Additionally, I-3 promotes melanin production by regulating tryptophan metabolism. In summary, PPL is a promising drug target, and I-3 has strong potential for future treatment of vitiligo due to its high selectivity and favorable druggability.

Targeting ferroptosis in autoimmune diseases: Mechanisms and therapeutic prospects

Ferroptosis is a form of regulated cell death that relies on iron and exhibits unique characteristics, including disrupted iron balance, reduced antioxidant defenses, and abnormal lipid peroxidation. Recent research suggests that ferroptosis is associated with the onset and progression of autoimmune disorders such as systemic lupus erythematosus (SLE), rheumatoid arthritis (RA), inflammatory bowel disease (IBD), and multiple sclerosis (MS). However, the precise effects and molecular mechanisms remain incompletely understood. This article presents an overview of how ferroptosis mechanisms contribute to the development and advancement of autoimmune diseases, as well as the involvement of various immune cells in linking ferroptosis to autoimmune conditions. It also explores potential drug targets within the ferroptosis pathway and recent advancements in therapeutic approaches aimed at preventing and treating autoimmune diseases by targeting ferroptosis. Lastly, the article discusses the challenges and opportunities in utilizing ferroptosis as a potential therapeutic avenue for autoimmune disorders.

Tanshinone IIA Inhibits Hydrogen Peroxide-Induced Ferroptosis in Melanocytes through Activating Nrf2 Signaling Pathway

INTRODUCTION

Melanocyte ferroptosis has been proven to contribute to the development of vitiligo. Tanshinone IIA (TSA), a Chinese herbal extract, has been shown to inhibit vitiligo progression. Whether TSA regulates ferroptosis in melanocytes remains unclear.

METHODS

Hydrogen peroxide (H2O2) was used to induce melanocytes to stimulate vitiligo cell model in vitro. Cell proliferation was examined by 5-ethynyl-2'-deoxyuridine assay. The levels of malondialdehyde, reactive oxygen species, glutathione peroxidase, and iron were detected by corresponding commercial kit. The protein levels of ferroptosis-related markers and Nrf2 pathway-related markers were examined using western blot and immunofluorescence staining. Cell viability and cytotoxicity were analyzed using Cell Counting Kit-8 assay and lactate dehydrogenase detection. Mitochondrial morphology was examined using a transmission electron microscope.

RESULTS

After H2O2 treatment, melanocyte proliferation was reduced, while oxidative stress and ferroptosis were enhanced. TSA treatment could inhibit ferroptosis in H2O2-induced melanocytes. Besides, TSA could activate Nrf2 pathway and promote Nrf2 nuclear translocation, and Nrf2-specific inhibitor (ML385) also reversed the inhibitory effect of TSA on H2O2-induced melanocyte ferroptosis.

CONCLUSION

Our data showed that TSA alleviated H2O2-induced melanocyte ferroptosis via activating Nrf2 pathway.

The role of aryl hydrocarbon receptor agonists in the treatment of vitiligo

Vitiligo is a chronic autoimmune disorder characterized by progressive skin depigmentation. Vitiligo significantly impacts patients' quality of life, contributing to psychological and social burdens. Despite readily available therapeutic options, many cases remain refractory to treatment, highlighting the critical need for safer and more effective therapies. Currently, ruxolitinib is the only FDA-approved medication for vitiligo; however, it carries a black box warning for serious adverse effects, including infections, malignancy, and major cardiovascular events, limiting its use. Recent studies have identified the aryl hydrocarbon receptor (AhR) as a promising therapeutic target, suggesting that AhR agonists could address the multifaceted pathogenesis of vitiligo. Adhering to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, we conducted a comprehensive search to analyze the role of AhR agonists in the treatment of vitiligo on PubMed, Cochrane, Embase, MEDLINE, and Web of Science databases on April 15, 2024. Fourteen studies met the inclusion criteria, comprising two clinical trials, two case reports, and nine basic science studies. Our search revealed that culturing AhR agonists with melanocytes upregulates melanin-synthesizing enzymes, reduces reactive oxygen species, and modulates pro-inflammatory cytokines such as IL-17A and IL-22. Tapinarof, a topical AhR agonist used commonly for the treatment of psoriasis, demonstrated clinical efficacy in repigmentation with a favorable safety profile compared to long-term steroid use. Although limited by the number of clinical studies, this review underscores the potential of using AhR agonists, such as tapinarof, as a transformative approach to vitiligo management. Future clinical trials are necessary to evaluate the safety, efficacy, and long-term outcomes of AhR agonists.

Identification of Upregulating Genes, Transcription Factors, and miRNAs in Vitiligo. In silico Study

Background

Depigmentation of specific areas of the skin is a persistent and long-lasting dermatologic disorder known as vitiligo, stemming from the impairment and disruption of melanocytes both structurally and functionally, leading to the loss of pigmentation in those regions.

Aim

Our objective was to identify the pivotal genes and upstream regulators, transcription factors (TFs), microRNAs (miRNAs), and pathways implicated in the pathogenesis of vitiligo.

Methods

An integrated analysis was conducted using microarray datasets on vitiligo obtained from the Gene Expression Omnibus (GEO) database. The functional annotation and potential pathways of differentially expressed genes (DEGs) were additionally investigated through Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses. Various bioinformatics approaches were utilized, making use of publicly accessible databases to identify appropriate TFs and miRNAs.

Results

Our investigation identified TYR, MLANA, TYRP1, PMEL, OCA2, SLC45A2, GPR143, DCT, TRPM1, and EDNRB as the most appropriate genes associated with vitiligo. Our suggestion is that the identified biological processes include developmental pigmentation (GO:0048066) and pigment metabolic processes (GO:0042440) as the most suitable biological processes. In contrast, the KEGG pathways that showed significance in our analysis are Tyrosine metabolism (Path: hsa00350) and Melanogenesis (Path: hsa04916). We hypothesized the involvement of ten TFs and 73 miRNAs in the regulation of genes related to vitiligo.

Conclusion

TYR, MLANA, TYRP1, PMEL, OCA2, SLC45A2, GPR143, DCT, TRPM1, and EDNRB are the top ten genes that are pivotal in the progression and exhibition of vitiligo. The biological, cellular, molecular, and KEGG pathways of those genes has an imperative role in the pathogenesis of vitiligo. TFs and miRNAs that interact with this gene are listed, shedding light on the regulatory mechanisms governing the expression of these key genes in vitiligo.

miR-409-3p Regulates IFNG and p16 Signaling in the Human Blood of Aging-Related Hearing Loss

Presbycusis, also referred to as age-related hearing loss (ARHL), is a multifaceted condition caused by the natural aging process affecting the auditory system. Genome-wide association studies (GWAS) in human populations can identify potential genes linked to ARHL. Despite this, our knowledge of the biochemical and molecular mechanisms behind the condition remains incomplete. This study aims to evaluate a potential protective tool for ARHL treatment by comparing human blood-based target gene-miRNA associations regulated in ARHL. To identify promising target genes for ARHL, we utilized an mRNA assay. To determine the role of miRNA in ARHL, we investigated the expression profile of miRNA in whole blood in ARHL patients with real-time polymerase chain reaction (RT-qPCR). A reporter gene assay was performed to confirm the regulation of candidate genes by microRNA. Through RT-qPCR validation analysis, we finally confirmed the relationship between ARHL and the role of the interferon-gamma (IFNG) gene. This gene can be regarded as an age-related gene. Through gene ontology (GO) analysis, it has been found that these genes are enriched in pathways related to apoptosis. Among them, IFNG induces an inflammatory response, apoptotic cell death, and cellular senescence. We found that miR-409-3p downregulates the expression of the IFNG in vitro. In addition, the downregulation of the IFNG by miRNA 409-3p promoted cell apoptosis and suppressed proliferation. In conclusion, our study produced gene signatures and associated microRNA regulation that could be a protective key for ARHL patients. IFNG genes and miR-409-3p should be investigated for their usefulness as a new biomarker for treatment modality.

In-silico evaluation of phytochemicals for vitiligo: ADMET, molecular docking, and MD simulation approaches

Vitiligo is a prevalent autoimmune disease affecting the quality of life and self-confidence. Total 25 phytochemicals from plants were screened by using four target proteins involved in the pathogenesis of vitiligo. The binding affinity of the ligands ranged between -10.3 and -4.5 kcal/mol. The top 10 phytochemicals i.e. rosmarinic acid, piperine, tamarixetin, desmethoxycurcumin, bisdemethoxycurcumin, isorhamnetin, quercetin, vicenin II, genkwanin, and aloe-emodin showed good inhibition with binding affinity ranged from -10.3 to 9.4 Kcal. The ADMET profiling revealed that these phytochemicals might be safe for the treatment of vitiligo. In MD simulation, rosmarinic acid, piperine, and tamarixetin with MAO-A formed stable complexes and the free binding energies of the complexes were -34.02 ± 6.94, -33.51 ± 2.65, and -27.17 ± 3.28. Furthermore, the ligands formed hydrogen bonds with targets, suggested that rosmarinic acid, piperine, and tamarixetin have potential to serve as lead compounds for developing novel therapeutics for vitiligo after in vitro and in vivo studies.

Vitiligo: From Pathogenesis to Treatment

Recent advances in vitiligo have provided promising treatment options, particularly through understanding the immune-mediated mechanisms leading to depigmentation. The inflammatory components in both vitiligo (non-segmental) and segmental vitiligo have similarities. Both are believed to result from an immune-based destruction of melanocytes by anti-melanocyte-specific cytotoxic T cells. The JAK-STAT pathway is activated with IFN-γ as the crucial cytokine and Th1-associated chemokines such as CXCL9 and CXCL10 recruit immune cells towards vitiligo skin. Nonetheless, clear differences are also present, such as the localized nature of segmental vitiligo, likely due to somatic mosaicism and increased presence of poliosis. The differing prevalence of poliosis suggests that the follicular immune privilege, which is known to involve immune checkpoints, may be more important in vitiligo (non-segmental). Immunomodulatory therapies, especially those targeting the JAK-IFNγ pathway, are currently at the forefront, offering effective inhibition of melanocyte destruction by cytotoxic T cells. Although Janus Kinase (JAK) inhibitors demonstrate high repigmentation rates, optimal results can take several months to years. The influence of environmental UV exposure on repigmentation in patients receiving immunomodulating drugs remains largely underexplored. Nonetheless, the combined effect of phototherapy with JAK inhibitors is impressive and suggests a targeted immune-based treatment may still require additional stimulation of melanocytes for repigmentation. Identifying alternative melanocyte stimulants beyond UV light remains crucial for the future management of vitiligo.

Reliability of the Vitiligo Area Scoring Index measurement tool for vitiligo

Background

A reliable instrument is needed to assess vitiligo severity and treatment response.

Objective

To assess inter- and intrarater variability and accuracy of the Vitiligo Area Scoring Index among trained raters and to evaluate a proposed Vitiligo Area Scoring Index using equidistant 10% depigmentation increments (VASI 10%).

Methods

In this prospective study, 12 raters evaluated images of 10 participants with vitiligo on 2 occasions using total body Vitiligo Area Scoring Index (T-VASI) and facial Vitiligo Area Scoring Index (F-VASI) scores after training. Inter- and intrarater reliabilities and accuracy vs digital scores were determined using intraclass correlation coefficients. VASI 10% scores were evaluated separately for interrater reliability and accuracy.

Results

F-VASI interrater reliability improved from "moderate" to "good" between time points, while T-VASI was "good" at both time points. Intrarater reliability ranged from "good" to "excellent" for T-VASI and "poor" to "excellent" for F-VASI. Accuracy intraclass correlation coefficient was "good" to "excellent" for most raters. Interrater reliability using VASI 10% was "moderate" for both T-VASI and F-VASI.

Limitations

Small participant population and number of raters; participants were not assessed in person; no repeated VASI 10% measures.

Conclusion

Vitiligo Area Scoring Index generally provides good to excellent reliability for assessment of vitiligo by raters who receive standardized training.

3D-hUMSCs Exosomes Ameliorate Vitiligo by Simultaneously Potentiating Treg Cells-Mediated Immunosuppression and Suppressing Oxidative Stress-Induced Melanocyte Damage

Vitiligo is an autoimmune disease characterized by epidermal melanocyte destruction, with abnormal autoimmune responses and excessive oxidative stress as two cardinal mechanisms. Human umbilical mesenchymal stem cells-derived exosomes (hUMSCs-Exos) are regarded as promising therapeutic choice for autoimmune diseases due to potent immunosuppressive and anti-oxidative properties, which can be potentiated under 3D cell culture condition. Nevertheless, whether exosomes derived from 3D spheroids of hUMSCs (3D-Exos) exhibit considerable therapeutic effect on vitiligo and the underlying mechanism remain elusive. In this study, systemic administration of 3D-Exos showed a remarkable effect in treating mice with vitiligo, as revealed by ameliorated skin depigmentation, less CD8+T cells infiltration, and expanded Treg cells in skin, and 3D-Exos exerted a better effect than 2D-Exos. Mechanistically, 3D-Exos can prominently facilitate the expansion of Treg cells in vitiligo lesion and suppress H2O2-induced melanocytes apoptosis. Forward miRNA profile analysis and molecular experiments have demonstrated that miR-132-3p and miR-125b-5p enriched in 3D-Exos greatly contributed to these biological effects by targeting Sirt1 and Bak1 respectively. In aggregate, 3D-Exos can efficiently ameliorate vitiligo by simultaneously potentiating Treg cells-mediated immunosuppression and suppressing oxidative stress-induced melanocyte damage via the delivery of miR-132-3p and miR-125b-5p. The employment of 3D-Exos will be a promising treament for vitiligo.

Abnormal metabolism in melanocytes participates in the activation of dendritic cell in halo nevus

A comprehensive analysis of spatial transcriptomics was carried out to better understand the progress of halo nevus. We found that halo nevus was characterized by overactive immune responses, triggered by chemokines and dendritic cells (DCs), T cells, and macrophages. Consequently, we observed abnormal cell death, such as apoptosis and disulfidptosis in halo nevus, some were closely related to immunity. Interestingly, we identified aberrant metabolites such as uridine diphosphate glucose (UDP-G) within the halo nevus. UDP-G, accompanied by the infiltration of DCs and T cells, exhibited correlations with certain forms of cell death. Subsequent experiments confirmed that UDP-G was increased in vitiligo serum and could activate DCs. We also confirmed that oxidative response is an inducer of UDP-G. In summary, the immune response in halo nevus, including DC activation, was accompanied by abnormal cell death and metabolites. Especially, melanocyte-derived UDP-G may play a crucial role in DC activation.

Mechanism of desuccinylation of G6PD mediated by SIRT7 to promote vitiligo disease progression

BACKGROUND

Sirtuin 7 (SIRT7) is pivotal in diverse diseases progression. Importantly, SIRT7 is associated with melanin production. However, whether SIRT7 regulates vitiligo is unclear. Therefore, we aimed to investigate the effects of SIRT7 on pigmentation and the modification of glucose 6-phosphate dehydrogenase (G6PD).

METHODS

After knockdown SIRT7 and G6PD, pigmentation of melanocytes was evaluated using commercial kits, immunofluorescence, and Western blot analysis. The succinylation of G6PD mediated by SIRT7 was analyzed using co-immunoprecipitation, immunofluorescence, Western blot analysis, and cycloheximide-chase experiment.

RESULTS

We found that SIRT7 was highly expressed in vitiligo skin lesions. Knockdown of SIRT7 increased tyrosinase activity, melanin content, and the levels of α-melanocyte-stimulating hormone, MITF, TYR, TRP1, and TRP2. Additionally, SIRT7 directly interacted with G6PD. Silenced SIRT7 promoted the succinylation of G6PD and enhanced its protein stability. G6PD knockdown reversed the effect of reduced SIRT7 expression on melanin production.

CONCLSUION

Silencing of SIRT7 promotes pigmentation of melanocytes by succinylating G6PD, suggesting that SIRT7-mediated G6PD desuccinylation may promote vitiligo progression.

Chemical leukoderma: An insight of pathophysiology and contributing factors

Chemical leukoderma, or chemical-based vitiligo, is a dermal disease triggered by exposure to chemicals and characterized by the emergence of depigmentation or hypopigmentation of the skin. The etiology of this condition is associated with exposure to various chemical substances present in both occupational and non-occupational settings. The precise mechanism that underlies chemical leukoderma remains elusive and is believed to result from the demise of melanocytes, which are responsible for producing skin pigments. This condition has gained particular prominence in developing countries like India. An interesting connection between chemical leukoderma and vitiligo has been identified; studies suggest that exposure to many household chemicals, which are derivatives of phenols and catechol, may serve as a primary etiological factor for the condition. Similar to autoimmune diseases, its pathogenesis involves contributions from both genetic and environmental factors. Furthermore, over the last few decades, various studies have demonstrated that exposure to chemicals plays a crucial role in initiating and progressing chemical leukoderma, including cases stemming from occupational exposure.

Efficacy of fire needle combined with 308 nm excimer laser therapy for vitiligo: A systematic review and meta-analysis of randomized controlled trials

INTRODUCTION

Vitiligo is a common depigmenting skin disorder. This work is performed to systematically evaluate the efficacy and safety of fire needles combined with 308 nm excimer laser therapy in treating vitiligo.

METHODS

We searched the PubMed, EMBASE, Cochrane Library, Web of Science, CNKI, Wanfang, and VIP databases. Randomized controlled trials (RCTs) on fire needles combined with 308 nm excimer laser therapy with 308 nm excimer laser therapy alone for vitiligo were included. The Cochrane Collaborative Network Tool was used to assess the risk of bias. Statistical analysis was completed using RevMan5.3 software and Stata 15.0 software. The GRADE system was used to evaluate the quality of evidence for outcomes.

RESULTS

In this study, 10 RCTs and 1333 patients were included. The results showed that compared with 308 nm excimer laser therapy alone, fire needle combined with 308 nm excimer laser therapy is more effective in improving clinical effective rate (RR = 1.36, 95% CI [1.24, 1.50], p < 0.00001), serum CD4+ level (MD = 3.12, 95% CI [2.50, 3.74], p < 0.00001), CD4+/CD8+ ratio (MD = 0.24, 95% CI [0.09, 0.39], p = 0.001), and quality of life measured by the Dermatology Life Quality Index (DLQI) (MD = 3.76, 95% CI [3.33, 4.19], p < 0.00001), and reducing the Vitiligo Area Score Index (VASI) (MD = -5.47, 95% CI [-6.56, -4.37], p < 0.00001). The reported adverse events, including redness, swelling, pain, blisters, and itching, were controllable, and all these events were well tolerated.

CONCLUSION

The current evidence indicates that fire needle combined with 308 nm excimer laser therapy is effective and safe for vitiligo. However, owing to the suboptimal quality of the included studies, more high-quality and large-scale RCTs are needed for comprehensive analysis and further validation.

Skin Aging and the Upcoming Role of Ferroptosis in Geroscience

The skin is considered the most important organ system in mammals, and as the population ages, it is important to consider skin aging and anti-aging therapeutic strategies. Exposure of the skin to various insults induces significant changes throughout our lives, differentiating the skin of a young adult from that of an older adult. These changes are caused by a combination of intrinsic and extrinsic aging. We report the interactions between skin aging and its metabolism, showing that the network is due to several factors. For example, iron is an important nutrient for humans, but its level increases with aging, inducing deleterious effects on cellular functions. Recently, it was discovered that ferroptosis, or iron-dependent cell death, is linked to aging and skin diseases. The pursuit of new molecular targets for ferroptosis has recently attracted attention. Prevention of ferroptosis is an effective therapeutic strategy for the treatment of diseases, especially in old age. However, the pathological and biological mechanisms underlying ferroptosis are still not fully understood, especially in skin diseases such as melanoma and autoimmune diseases. Only a few basic studies on regulated cell death exist, and the challenge is to turn the studies into clinical applications.

Exosome-derived microRNAs: emerging players in vitiligo

Exosome-derived microRNAs (miRNAs) are biomacromolecules and nanoscale extracellular vesicles originating from intracellular compartments that are secreted by most cells into the extracellular space. This review examines the formation and function of exosomal miRNAs in biological information transfer, explores the pathogenesis of vitiligo, and highlights the relationship between exosomal miRNAs and vitiligo. The aim is to deepen the understanding of how exosomal miRNAs influence immune imbalance, oxidative stress damage, melanocyte-keratinocyte interactions, and melanogenesis disorders in the development of vitiligo. This enhanced understanding may contribute to the development of potential diagnostic and therapeutic options for vitiligo.

Evaluation of ruxolitinib cream 1.5% as an at-home therapy for repigmentation in non-segmental vitiligo

INTRODUCTION

Vitiligo is a chronic, autoimmune condition characterized by skin depigmentation caused by inflammatory-mediated melanocyte degradation. Treatment of vitiligo is challenging due to the chronic nature of the condition. Ruxolitinib cream 1.5% was recently approved by the Food and Drug Administration (FDA) as a Janus kinase 1 and 2 inhibitor for use in nonsegmental vitiligo for those 12 years and older.

AREAS COVERED

The purpose of this review is to describe the role of ruxolitinib in treating nonsegmental vitiligo.We searched PubMed using search terms nonsegmental vitiligo, jak inhibitor, and ruxolitinib. Clinicaltrials.gov was used to identify clinical trial data including efficacy, pharmacodynamics, pharmacokinetics, safety, and tolerability.

EXPERT OPINION

In both phase II and phase III (TRuE-V1 and TRuE-V2) trials, ruxolitinib cream 1.5% improved repigmentation with minimal adverse effects. Topical ruxolitinib is a much needed new vitiligo treatment option.  Real life efficacy may not match that seen in clinical trials if the hurdle of poor adherence to topical treatment is not surmounted.

Implication of regulatory T cells' telomere shortening in pathogenesis of generalized vitiligo

Generalized vitiligo(GV) is a skin depigmenting condition due to loss of melanocytes. Regulatory T cells(Tregs), responsible for peripheral tolerance, show altered numbers and functions in GV patients, likely influenced by the aging process. Therefore, the present study was focused on measuring the relative telomere length of Tregs in 96 GV patients and 90 controls by qPCR, along with correlation of relative telomere length with in vitro Treg suppressive capacity. Interestingly, we found significantly decreased relative telomere length in Tregs of GV patients as compared to controls(p = 0.0001). Additionally, age based-analysis suggested significant decrease in relative telomere length in elderly GV patients(>40 years) in comparison to young GV patients(0-20 years; p = 0.0027). Furthermore, age of onset analysis suggested for reduced relative telomere length in early onset GV patients (0-20 years) in comparison to late onset GV patients(>40 years; p = 0.0036). The correlation analysis suggested positive correlation for relative telomere length with in vitro Tregs suppressive capacity(r = 0.68 & r = 0.45; p < 0.0001). Additionally, the in vitro Tregs suppressive capacity was significantly reduced in elderly GV patients(p = 0.003) and early onset GV patients(p = 0.0074). Overall, our study for the first time demonstrated that, the Tregs ageing due to telomere shortening may be responsible for altered Treg functions and number.

Membranal Expression of Calreticulin Induced by Unfolded Protein Response in Melanocytes: A Mechanism Underlying Oxidative Stress-Induced Autoimmunity in Vitiligo

Calreticulin (CRT), a damage-associated molecular pattern molecule, is reported to translocate from the endoplasmic reticulum to the membrane in melanocytes under oxidative stress. To investigate the potential role of CRT in the pathogenesis of vitiligo, we analyzed the correlation between CRT and ROS in serum and lesions of vitiligo, detected CRT and protein kinase RNA-like endoplasmic reticulum kinase (PERK) expression in vitiligo lesions, and studied the production of CRT and mediators of unfolded protein response (UPR) pathway and then tested the chemotactic migration of CD8+ T cells or CD11c+ CD86+ cells. Initially, we verified the overexpression of CRT in perilesional epidermis that was positively correlated with the disease severity of vitiligo. Furthermore, the PERK branch of UPR was confirmed to be responsible for the overexpression and membranal translocation of CRT in melanocytes under oxidative stress. We also found that oxidative stress-induced membranal translocation of CRT promoted the activation and migration of CD8+ T cells in vitiligo. In addition, dendritic cells from patients with vitiligo were also prone to maturation with the coincubation of melanocytes harboring membranal CRT. CRT could be induced on the membrane of melanocytes through UPR and might play a role in oxidative stress-triggered CD8+ T-cell response in vitiligo.

Mini-review: research and progress of oxeiptosis in diseases

Oxeiptosis is a novel cell death pathway that was introduced in 2018. As a form of regulated cell death, it operates independently of caspases and is induced by ROS. Distinguished from other cell death pathways such as apoptosis, necroptosis, pyroptosis, and ferroptosis, oxeiptosis features unique damage causes pivotal genes, and signaling pathways (KEAP1/PGAM5/AIFM1). Emerging studies indicate that oxeiptosis plays a significant role in the progression of various diseases and its regulation could serve as a promising therapeutic target. However, the precise molecular mechanisms underlying oxeiptosis remain to be fully elucidated. In this mini-review, we systematically summarize the latest developments in oxeiptosis-related diseases while detailing the molecular mechanisms and regulatory networks of oxeiptosis. These insights offer a foundation for a deeper understanding of oxeiptosis.

Oxidative stress-induced hypermethylation and low expression of ANXA2R: Novel insights into the dysfunction of melanocytes in vitiligo

BACKGROUND

Vitiligo is a skin disorder with melanocyte destruction caused by complex interplay between multiple genetic and environmental factors. Recent studies have suggested DNA methylation is involved in the melanocyte damage, but the underlying mechanism remains unknown.

OBJECTIVE

To explore the abnormal DNA methylation patterns in vitiligo lesional and nonlesional skin, and the mechanism of DNA methylation involved in vitiligo pathogenesis.

METHODS

Initially, the genome-wide aberrant DNA methylation profiles in lesional and nonlesional skin of vitiligo were detect via Illumina methylation EPIC 850k Beadchip. Subsequently, a comprehensive analysis was conduct to investigate the genomic characteristics of differentially methylated regions (DMRs). Furthermore, the effects of key aberrant methylated genes on cell apoptosis and function of both melanocytes and keratinocytes were further identified and validated by western bloting, ELISA, and immunofluorescence.

RESULTS

Compared with nonlesional skins, we discovered 79 significantly differentially methylated CpG sites in vitiligo lesions. These DMRs were mainly located in the gene body and the TS1500 region. Annexin A2 receptor (ANXA2R), a crucial gene in cell apoptosis, was hypermethylated in vitiligo lesions. Furthermore, we showed that ANXA2R displayed hypermethylation and low expression levels in both keratinocytes and melanocytes of vitiligo patients, and the hypermethylated-triggered downregulation of ANXA2R under oxidative stress induced melanocyte apoptosis, and inhibited the secretion of stem cell factor (SCF) from keratinocytes thus impaired the survival of melanocytes.

CONCLUSIONS

Our study illustrates the DNA methylation modification in vitiligo, and further demonstrates the molecular mechanism of hypermethylated ANXA2R in the dysfunction of melanocytes under oxidative stress.

Research progress on the mechanism and signalling pathway of ferroptosis and its potential role in dermatosis research

Ferroptosis is a novel type of cell death that is dependent on lipid peroxidation and iron accumulation, which distinguishes it from other types of programmed cell death. Current research indicates a significant association between ferroptosis and various pathological conditions, including cancer, neurological disorders, and cardiovascular diseases, albeit with a relatively unexplored role in dermatological afflictions. This paper elaborates on the mechanisms and signalling pathways of ferroptosis, summarizing the recent studies on ferroptosis and its related factors in dermatosis. Our objective is to shed light on novel perspectives and therapeutic strategies for dermatosis, enhancing the understanding of this under-researched area through this comprehensive review.

Combination of total glucosides of paeony, narrow-band ultraviolet B, and oral corticosteroid mini-pulse therapy for nonsegmental vitiligo: A retrospective study

BACKGROUND

The total glucoside of paeony (TGP) is recognized for its immunomodulatory properties and anti-inflammatory effects. This study evaluates the efficacy of TGP combined with oral mini-pulse therapy (OMP) and narrow-band ultraviolet B (NB-UVB) in treating active nonsegmental vitiligo (NSV).

MATERIALS AND METHODS

The combination therapy was contrasted against those from a group treated solely with OMP and NB-UVB. Data from 62 patients undergoing TGP combination treatment and 55 without were analyzed over a 3-month period. After 6 months, the differences in recurrence rate were investigated by follow-up.

RESULTS

The findings indicate that integrating TGP may yield superior outcomes compared to OMP + NB-UVB alone. Moreover, the patient's oxidative stress makers were significantly reduced after the treatment. The majority of patients in the TGP cohort exhibited enhanced skin pigmentation over the duration. Notably, no increase in side effects or recurrence was observed in this group. Especially, patients with vitiligo on their head and neck experienced pronounced improvements.

CONCLUSION

The efficacy of the combination treatment group was better than that of the control group at 2 and 3 months, and there was no difference in recurrence rate and side effects, suggesting that TGP may continue to show efficacy in NSV for a longer period of time by reducing the level of oxidative stress, and is especially suitable for patients with head and neck lesions.

Transient receptor potential mucolipin 1 circumvents oxidative stress in primary human melanocytes

BACKGROUND

Transient Receptor Potential Mucolipin 1 (TRPML1) serves as a pivotal reactive oxygen species (ROS) sensor in cells, which is implicated in the regulation of autophagy. However, its function in melanocyte autophagy under oxidative stress remains elusive.

METHODS

The expression and ion channel function of TRPML1 were investigated using immunofluorescence and calcium imaging in primary human melanocytes (MCs). After activating TRPML1 with MLSA1 (TRPML1 agonist), autophagy-related molecules were investigated via western blot. ROS level, apoptosis- and autophagy-related molecules were investigated after pretreatment with MLSA1. After interference with TRPML1 expression, mitochondrial structures were visualized by electron microscopy with hydrogen peroxide (H2O2）treatment.

RESULTS

TRPML1 was expressed and functionally active in primary human MCs, and its activation promotes elevated expression of LC3-II and reduced apoptosis and ROS levels under oxidative stress. TRPML1 downregulation caused mitochondrial swelling and disruption of cristae structures under oxidative stress in primary human MCs.

CONCLUSIONS

TRPML1 might mediate lysosomal autophagy in primary human MCs under oxidative stress, participating in mechanisms that maintain the oxidative and antioxidant systems in balance.

Roles of blood metabolites in mediating the relationship between vitiligo and autoimmune diseases: Evidence from a Mendelian randomization study

OBJECTIVE

This study employed Mendelian Randomization (MR) to investigate the causal relationship between genetic susceptibility to vitiligo and the risk of various autoimmune diseases, along with the mediating role of blood metabolites.

METHODS

We performed two-sample MR analyses using aggregated genome-wide association studies (GWAS) data on 486 blood metabolites, vitiligo, and nine autoimmune diseases to investigate blood metabolites' causal effects on the susceptibility of vitiligo and the associations of vitiligo with nine autoimmune comorbidities. We also applied multivariable MR to unravel metabolites by which vitiligo influences the pathogenesis of autoimmune diseases.

RESULTS

Our findings indicate that vitiligo amplified the risk of several autoimmune diseases, including rheumatoid arthritis (OR 1.17; 95 % CI 1.08-1.27), psoriasis (OR 1.10; 95 % CI 1.04-1.17), type 1 diabetes (OR 1.41; 95 % CI 1.23-1.63), pernicious anemia (OR 1.23; 95 % CI 1.12-1.36), autoimmune hypothyroidism (OR 1.19; 95 % CI 1.11-1.26), alopecia areata (OR 1.22; 95 % CI 1.10-1.35), and autoimmune Addison's disease (OR 1.22; 95 % CI 1.12-1.33). Additionally, our analysis identified correlations with vitiligo for 14 known (nine risk, five protective) and seven uncharacterized serum metabolites. After adjusting for genetically predicted levels of histidine and pyruvate, the associations between vitiligo and these diseases were attenuated.

CONCLUSIONS

We substantiated vitiligo's influence on susceptibility to seven autoimmune diseases and conducted a thorough investigation of serum metabolites correlated with vitiligo. Histidine and pyruvate are potential mediators of vitiligo associated with autoimmune diseases.By combining metabolomics with genomics, we provide new perspectives on the etiology of vitiligo and its immune comorbidities.

Type-2 immunity associated with type-1 related skin inflammatory diseases: friend or foe?

Chronic inflammatory skin diseases are multifactorial diseases that combine genetic predisposition, environmental triggers, and metabolic disturbances associated with abnormal immune responses. From an immunological perspective, the better understanding of their physiopathology has demonstrated a large complex network of immune cell subsets and related cytokines that interact with both epidermal and dermal cells. For example, in type-1-associated diseases such as alopecia areata, vitiligo, and localized scleroderma, recent evidence suggests the presence of a type-2 inflammation that is well known in atopic dermatitis. Whether this type-2 immune response has a protective or detrimental impact on the development and chronicity of these diseases remains to be fully elucidated, highlighting the need to better understand its involvement for the management of patients. This mini-review explores recent insights regarding the potential role of type-2-related immunity in alopecia areata, vitiligo, and localized scleroderma.

Vogt-Koyanagi-Harada Syndrome Following COVID-19 mRNA Vaccination: Th2 to Th1 Transition-related Molecular Machinery

Abstract is missing (Short communication)

Capsaicin combined with stem cells improved mitochondrial dysfunction in PIG3V cells, an immortalized human vitiligo melanocyte cell line, by inhibiting the HSP70/TLR4/mTOR/FAK signaling axis

BACKGROUND

Vitiligo is a common autoimmune skin disease. Capsaicin has been found to exert a positive effect on vitiligo treatment, and mesenchymal stem cells (MSCs) are also confirmed to be an ideal cell type. This study aimed to explore the influence of capsaicin combined with stem cells on the treatment of vitiligo and to confirm the molecular mechanism of capsaicin combined with stem cells in treating vitiligo.

METHODS AND RESULTS

PIG3V cell proliferation and apoptosis were detected using CCK-8 and TUNEL assays, MitoSOX Red fluorescence staining was used to measure the mitochondrial ROS level, and JC-1 staining was used to detect the mitochondrial membrane potential. The expression of related genes and proteins was detected using RT‒qPCR and Western blotting. Coimmunoprecipitation was used to analyze the protein interactions between HSP70 and TLR4 or between TLR4 and mTOR. The results showed higher expression of HSP70 in PIG3V cells than in PIG1 cells. The overexpression of HSP70 reduced the proliferation of PIG3V cells, promoted apoptosis, and aggravated mitochondrial dysfunction and autophagy abnormalities. The expression of HSP70 could be inhibited by capsaicin combined with MSCs, which increased the levels of Tyr, Tyrp1 and DCT, promoted the proliferation of PIG3V cells, inhibited apoptosis, activated autophagy, and improved mitochondrial dysfunction. In addition, capsaicin combined with MSCs regulated the expression of TLR4 through HSP70 and subsequently affected the mTOR/FAK signaling pathway CONCLUSIONS: Capsaicin combined with MSCs inhibits TLR4 through HSP70, and the mTOR/FAK signaling pathway is inhibited to alleviate mitochondrial dysfunction and autophagy abnormalities in PIG3V cells.

From mice to men: An assessment of preclinical model systems for the study of vitiligo

Vitiligo is an autoimmune skin disease of multiple etiology, for which there is no complete cure. This chronic depigmentation is characterized by epidermal melanocyte loss, and causes disfigurement and significant psychosocial distress. Mouse models have been extensively employed to further our understanding of complex disease mechanisms in vitiligo, as well as to provide a preclinical platform for clinical interventional research on potential treatment strategies in humans. The current mouse models can be categorized into three groups: spontaneous mouse models, induced mouse models, and transgenic mice. Despite their limitations, these models allow us to understand the pathology processes of vitiligo at molecule, cell, tissue, organ, and system levels, and have been used to test prospective drugs. In this review, we comprehensively evaluate existing murine systems of vitiligo and elucidate their respective characteristics, aiming to offer a panorama for researchers to select the appropriate mouse models for their study.