Neurogenic dysregulation, oxidative stress, autoimmunity, and melanocytorrhagy in vitiligo: can they be interconnected?

Galangin ameliorates PTU-induced vitiligo in zebrafish and B16F10 cells by increasing melanogenesis through activation of the p38/JNK MAPK pathway

Objective

Alpinia officinarum Hance is a traditional herb in Xinjiang for the treatment of vitiligo, and galangin (GA) is a flavonoid isolated from its roots. However, its therapeutic mechanism remains unclear.

Methods

In this study, 1-phenyl-2-thiourea (PTU) was used to establish a vitiligo model in zebrafish. After successful modeling, different concentrations of GA (1 and 2 μM) were administered, and the distribution of melanin granules was observed by assaying the melanin content, masson-fontana staining and tyrosinase activity. Transcriptomic analysis and molecular docking were used to identify potential GA-related pathways and targets for improving vitiligo. In addition, we evaluated the proliferation of B16F10 cells by PTU induction and also observed cellular melanin distribution using masson-fontana staining. Finally, Western blot was performed to detect the proteins of the relevant pathways.

Results

The results showed that GA significantly increased melanin production and tyrosinase activity in depigmented zebrafish. In addition, we found that GA decreased ROS and MDA levels and increased the expression of GSH, CAT and T-SOD. In addition, transcriptome analysis indicated that GA likely acts through the mitogen-activated protein kinase (MAPK) signaling pathway. GA has a strong binding affinity for important targets.GA significantly increased the expression of genes such as mapk8b, mapk14a, mapk3, mitf, tyr, tyrp1b, tyrp1a, dct, and oca2, and decreased the expression of genes such as expression of genes such as raf1 and egfr. In addition, GA enhanced the viability of B16F10 cells, increased intracellular melanin content, and increased the expression of proteins such as p38, JNK1/2/3, TYR, MITF, TRP1, TRP2, and so on.

Conclusion

GA increases melanin production and distribution, improves tyrosinase activity, upregulates the expression of related genes and proteins through activation of MAPK and tyrosine metabolic pathways, downregulates oxidative stress, and then regulates changes in melanin synthesis to improve vitiligo.

The influence of phototherapy on circadian melatonin and sleep regulation and potential benefits of these pathways in the management of vitiligo: a narrative review : Vitiligo, phototherapy, sleep and melatonin

Ultraviolet B narrow band (UVB-NB) phototherapy is the gold standard treatment for vitiligo, primarily due to its immunomodulatory effects. Additionally, it may influence circadian melatonin balance, that may indirectly induce sleep regulation, which in turn could potentially contribute to vitiligo improvement. The association between melatonin, vitiligo and phototherapy has been little investigated. The aim of this study was to evaluate the current evidence regarding the effects of circadian melatonin regulation and sleep, particularly during vitiligo treatment with phototherapy. We undertook a narrative review to synthetize the evidence on this association through the MEDLINE/PubMed database, using combined search terms: melatonin, vitiligo, phototherapy, and circadian rhythm (sleep). A total of 56 articles were included. There are few studies on this relationship, and conflicting findings. Some studies have suggested that UV exposure and phototherapy might benefit vitiligo by stimulating melanocytes, which have melatonin receptors, and this could potentially synchronize the circadian regulation of melatonin. This improved melatonin balance could result in better sleep quality further enhancing the antiinflammatory properties of melatonin and contributing to vitiligo improvement. Less is known about the possible effects of the use of topical melatonin, with or without phototherapy, to treat vitiligo lesions. In conclusion, there is some evidence that circadian melatonin regulation plays an important role in the course of vitiligo, both through sleep regulation and its anti-inflammatory properties. The evidence suggests that the systemic and physiological properties of melatonin, especially its circadian behavior regulated by phototherapy, may be more effective in respect of vitiligo improvement than the use of topical melatonin. However, the effects of the oral intake of melatonin are less clear. Phototherapy, as a potential modulator of circadian melatonin rhythm, that influences sleep and clinical improvement of vitiligo, needs further examination, as does the use of melatonin as an adjuvant treatment to UVB phototherapy in vitiligo.

Small-molecule agents for treating skin diseases

Skin diseases are a class of common and frequently occurring diseases that significantly impact daily lives. Currently, the limited effective therapeutic drugs are far from meeting the clinical needs; most drugs typically only provide symptomatic relief rather than a cure. Developing small-molecule drugs with improved efficacy holds paramount importance for treating skin diseases. This review aimed to systematically introduce the pathogenesis of common skin diseases in daily life, list related drugs applied in the clinic, and summarize the clinical research status of candidate drugs and the latest research progress of candidate compounds in the drug discovery stage. Also, it statistically analyzed the number of publications and global attention trends for the involved skin diseases. This review might provide practical information for researchers engaged in dermatological drugs and further increase research attention to this disease area.

Based on network pharmacology and bioinformatics to analyze the mechanism of action of Astragalus membranaceus in the treatment of vitiligo and COVID-19

Coronavirus disease 2019 (COVID-19) is spreading rapidly around the world. However, the treatment of vitiligo combined with COVID-19 has not been reported. Astragalus membranaceus (AM) has a therapeutic effect on patients with vitiligo and COVID-19. This study aims to discover its possible therapeutic mechanisms and provide potential drug targets. Using the Chinese Medicine System Pharmacological Database (TCMSP), GEO database and Genecards websites and other databases, AM target, vitiligo disease target, and COVID-19 related gene set were established. Then find the crossover genes by taking the intersection. Then use GO, KEGG enrichment analysis, and PPI network to discover its underlying mechanism. Finally, by importing drugs, active ingredients, crossover genes, and enriched signal pathways into Cytoscape software, a "drug-active ingredient-target signal pathway-" network is constructed. TCMSP screened and obtained 33 active ingredients including baicalein (MOL002714), NEOBAICALEIN (MOL002934), Skullcapflavone II (MOL002927), and wogonin (MOL000173), which acted on 448 potential targets. 1166 differentially expressed genes for vitiligo were screened by GEO. CIVID-19 related genes were screened by Genecards. Then by taking the intersection, a total of 10 crossover genes (PTGS2, CDK1, STAT1, BCL2L1, SCARB1, HIF1A, NAE1, PLA2G4A, HSP90AA1, and HSP90B1) were obtained. KEGG analysis found that it was mainly enriched in signaling pathways such as IL-17 signaling pathway, Th17 cell differentiation, Necroptosis, NOD-like receptor signaling pathway. Five core targets (PTGS2, STAT1, BCL2L1, HIF1A, and HSP90AA1) were obtained by analyzing the PPI network. The network of "active ingredients-crossover genes" was constructed by Cytoscape, and the 5 main active ingredients acting on the 5 core crossover genes acacetin, wogonin, baicalein, bis2S)-2-ethylhexyl) benzene-1,2-dicarboxylate and 5,2'-Dihydroxy-6,7,8-trimethoxyflavone. The core crossover genes obtained by PPI and the core crossover genes obtained by the "active ingredient-crossover gene" network are intersected to obtain the three most important core genes (PTGS2, STAT1, HSP90AA1). AM may act on PTGS2, STAT1, HSP90AA1, etc. through active components such as acacetin, wogonin, baicalein, bis2S)-2-ethylhexyl) benzene-1,2-dicarboxylate and 5,2'-Dihydroxy-6,7,8-trimethoxyflavone to activate IL-17 signaling pathway, Th17 cell differentiation, Necroptosis, NOD-like receptor signaling pathway, Kaposi sarcoma-associated herpesvirus infection, and VEGF signaling pathway and other signaling pathways to achieve the effect of treating vitiligo and COVID-19.

Catecholamines' accumulation and their disturbed metabolism at perilesional site: a possible cause of vitiligo progression

Catecholamines (epinephrine, norepinephrine and dopamine) are considered toxic to the melanocytes and may play an important role in the development of depigmented patches on the skin. This study was done to evaluate the levels of catecholamines in skin and plasma samples of active vitiligo patients' and gene expression changes in catecholamines' metabolism regulatory genes (COMT and GTPCH1), immunoregulatory genes (CTLA4 and PTPN22), and Catalase in active vitiligo patients. In this single-centre, prospective, case-control study, 30 patients with active vitiligo were recruited and skin biopsies from the perilesional site and plasma samples were collected. Skin biopsies from the normal site in vitiligo patients and healthy controls (n = 15) and plasma samples from controls were also obtained. Catecholamines' estimation was done via high-performance liquid chromatography. Gene expression variations were investigated via reverse transcription-polymerase chain reaction (PCR) and real-time PCR. Epinephrine, norepinephrine and dopamine levels were significantly higher in perilesional skin biopsies as compared to controls (P = 0.035, 0.024, and 0.006, respectively). However, epinephrine, norepinephrine and dopamine levels observed in patients' plasma samples were comparable to controls. The mRNA expression level of the Catalase gene was found to be upregulated at the perilesional site of patients as compared to the non-affected site of same patients (P < 0.001) and healthy controls (P = 0.037). Transcriptional expression of GTPCH1 and COMT were observed to be increased significantly at the perilesional site of patients in comparison to controls (P = 0.004 and P = 0.046, respectively). Our results support the presence of oxidative stress, inflammation and induced immune response in vitiligo patients at the perilesional sites. The increased inflammatory response may lead to catecholamines upregulation resulting in oxidative stress and melanocyte damage.

Predicting the risk of autoimmune thyroid disease in patients with vitiligo: Development and assessment of a new predictive nomogram

BACKGROUND

This study aimed to develop an autoimmune thyroid disease (AITD) risk prediction model for patients with vitiligo based on readily available characteristics.

METHODS

A retrospective analysis was conducted on the clinical characteristics, demographics, skin lesions, and laboratory test results of patients with vitiligo. To develop a model to predict the risk of AITD, the Least Absolute Shrinkage and Selection Operator (LASSO) method was used to optimize feature selection, and logistic regression analysis was used to select further features. The C-index, Hosmer-Lemeshow test, and decision curve analysis were used to evaluate the calibration, discrimination ability and clinical utility of the model. Internally, the model was verified using bootstrapping; externally, two independent cohorts were used to confirm model accuracy.

RESULTS

Sex, vitiligo type, family history of AITD, family history of other autoimmune disease, thyroid nodules or tumors, negative emotions, skin involvement exceeding 5% of body surface area, and positive immune serology (IgA, IgG, IgM, C3, and C4) were predictors of AITD in the prediction nomogram. The model showed good calibration and discrimination (C-index: 0.746; 95% confidence interval: 0.701-0.792). The accuracy of this predictive model was 74.6%.In both internal validation (a C-index of 1000 times) and external validation, the C-index outperformed (0.732, 0.869, and 0.777). The decision curve showed that the AITD nomogram had a good guiding role in clinical practice.

CONCLUSION

The novel AITD nomogram effectively evaluated the risk of AITD in patients with vitiligo.

Study of Novel Furocoumarin Derivatives on Anti-Vitiligo Activity, Molecular Docking and Mechanism of Action

Vitiligo is a common chronic dermatological abnormality that afflicts tens of millions of people. Furocoumarins isolated from Uygur traditional medicinal material Psoralen corylifolia L. have been proven to be highly effective for the treatment of vitiligo. Although many furocoumarin derivatives with anti-vitiligo activity have been synthesized, their targets with respect to the disease are still ambiguous. Fortunately, the JAKs were identified as potential targets for the disease and its inhibitors have been proved to be effective in the treatment of vitiligo in many clinical trials. Thus, sixty-five benzene sulfonate and benzoate derivatives of furocoumarins (7a–7ad, 8a–8ag) with superior anti-vitiligo activity targeting JAKs were designed and synthesized based on preliminary research. The SAR was characterized after the anti-vitiligo-activity evaluation in B16 cells. Twenty-two derivatives showed more potent effects on melanin synthesis in B16 cells than the positive control (8-MOP). Among them, compounds 7y and 8 not only could increase melanin content, but they also improved the catecholase activity of tyrosinase in a concentration-dependent manner. The docking studies indicated that they were able to interact with amino acid residues in JAK1 and JAK2 via hydrogen bonds. Furthermore, candidate 8 showed a moderate inhibition of CXCL−10, which plays an important role in JAK–STAT signaling. The RT-PCR and Western blotting analyses illustrated that compounds 7y and 8 promoted melanogenesis by activating the p38 MAPK and Akt/GSK-3β/β-catenin pathways, as well as increasing the expressions of the MITF and tyrosinase-family genes. Finally, furocoumarin derivative 8 was recognized as a promising candidate for the fight against the disease and worthy of further research in vivo.

Dopamine toxicity contributes to melanocyte loss via melanocytorrhagy: an in vitro study

BACKGROUND

Catecholamines (epinephrine, norepinephrine, and dopamine) have been proposed as a possible cause of melanocyte loss. Dopamine has been observed to cause apoptosis in melanocytes via reactive oxygen species development, but the effect on melanocyte adhesion and proliferation still remains to be elucidated. Thus, we explored the dose- and time-dependent toxicity of catecholamines and the effect of dopamine on the proliferation and adhesion potential of melanocytes.

MATERIALS AND METHODS

Primary culture of melanocytes was investigated in vitro for toxic effects of epinephrine, norepinephrine, and dopamine on metabolic activity via MTT [3-(4,5-dimethylthiazol-2-yl)-2,5 diphenyl tetrazolium bromide) assay. Cells were observed microscopically for any phenotypic changes. Further cell proliferation, cell adhesion, and cell death pathway were explored under dopamine toxicity in dose- and time-dependent manner with RNase/PI method of cell cycle analysis, cell adhesion assay, and Annexin V-FITC/PI assay, respectively. Altered gene expressions were confirmed with a real-time polymerase chain reaction.

RESULTS

Metabolic activity of cells varied with time and different doses of epinephrine, norepinephrine, and dopamine. Dopamine was observed to be more toxic than epinephrine and norepinephrine. Melanocytes were observed to follow different cell death pathways at comparatively lower and higher concentrations of dopamine. Persistent exposure to dopamine resulted in decreased cell proliferation and adhesion potential with apoptotic changes. Gene expression changes also confirmed the weak adhesion and survival potential of cells under the toxic effects of dopamine.

CONCLUSION

Dopamine can alter melanocytes' adhesion and survival potential, leading to apoptotic cell death or melanocytorrhagic loss.

Melanocytes and keratinocytes morphological changes in vitiligo patients. A histological, immunohistochemical and ultrastructural analysis

Vitiligo is an idiopathic acquired chronic stigmatizing disease. It is a pigmentary disorder that affects the skin and the mucous membranes, and it is characterized by well-circumscribed, depigmented milky white macules and patches. It has an estimated prevalence of 0.5-2% of the population worldwide. In the previous studies, several mechanisms such as autoimmune, oxidative stress, genetic factors, melanocytorrhagy, and neural hypothesis have been suggested for vitiligo pathogenesis.We aimed to assess the morphological changes of epidermal melanocytes and keratinocytes in patients with vitiligo. This aim will be fulfilled by histological, ultrastructural, and immunohistochemical analysis of skin biopsies from lesioned and non-lesioned sites in vitiligo patients.The study was carried out on 15 selected patients with stable vitiligo vulgaris but not receiving treatment in the last year and they fulfilled our inclusion criteria.Biopsies were taken from lesioned and non-lesioned sites in the same vitiligo patients, and they are processed for examinations by LM (using Hx & E, and Masson Fontana stain), immunohistochemical analysis (using Melan-A, E-cadherin, and caspase-3), and TEM (to demonstrate the ultra-structures).By LM, staining with Hx & E, lesioned skin in vitiligo patients showed hyperkeratosis, basal vacuolization, acanthosis with an increase in the epidermal thickness, ballooning of keratinocytes, and spongiosis. Regarding melanocytes, we observed a few numbers of melanocytes, also we detected some basal epidermal cells contain brown melanin granules. Using Fontana-Masson stain, we found that the melanin pigment is present in both lesioned and non-lesioned skin of vitiligo patients. We confirmed the presence of melanocytes in the lesioned skin by the immunohistochemical staining with Melan-A. The epidermal cells in lesioned skin of vitiligo patients showed weak positive expression of E-cadherin between them and an increase in the number of apoptotic Caspase-3 positive cells. BY TEM, the lesioned skin in vitiligo patients showed that the keratinocytes and melanocytes had various degenerative changes, disturbance of desmosomes in between keratinocytes, and absence of melanosomes in the keratinocytes. The detected melanocytes were degenerated and contained some melanosomes, melanin granules, and autophagosomes.We concluded that vitiligo pathogenesis is a combination of several factors and cannot be explained by only one mechanism. The pathology in the lesioned vitiliginous skin is a combination of several degenerative changes in keratinocytes, and melanocytes.

Patho-immunological mechanisms of vitiligo: the role of the innate and adaptive immunities and environmental stress factors

Epidermal melanocyte loss in vitiligo, triggered by stresses ranging from trauma to emotional stress, chemical exposure or metabolite imbalance, to the unknown, can stimulate oxidative stress in pigment cells, which secrete damage-associated molecular patterns that then initiate innate immune responses. Antigen presentation to melanocytes leads to stimulation of autoreactive T-cell responses, with further targeting of pigment cells. Studies show a pathogenic basis for cellular stress, innate immune responses and adaptive immunity in vitiligo. Improved understanding of the aetiological mechanisms in vitiligo has already resulted in successful use of the Jak inhibitors in vitiligo. In this review, we outline the current understanding of the pathological mechanisms in vitiligo and locate loci to which therapeutic attack might be directed.

Anatomically distinct fibroblast subsets determine skin autoimmune patterns

The skin serves as a physical barrier and an immunological interface that protects the body from the external environment1-3. Aberrant activation of immune cells can induce common skin autoimmune diseases such as vitiligo, which are often characterized by bilateral symmetric lesions in certain anatomic regions of the body4-6. Understanding what orchestrates the activities of cutaneous immune cells at an organ level is necessary for the treatment of autoimmune diseases. Here we identify subsets of dermal fibroblasts that are responsible for driving patterned autoimmune activity, by using a robust mouse model of vitiligo that is based on the activation of endogenous auto-reactive CD8+ T cells that target epidermal melanocytes. Using a combination of single-cell analysis of skin samples from patients with vitiligo, cell-type-specific genetic knockouts and engraftment experiments, we find that among multiple interferon-γ (IFNγ)-responsive cell types in vitiligo-affected skin, dermal fibroblasts are uniquely required to recruit and activate CD8+ cytotoxic T cells through secreted chemokines. Anatomically distinct human dermal fibroblasts exhibit intrinsic differences in the expression of chemokines in response to IFNγ. In mouse models of vitiligo, regional IFNγ-resistant fibroblasts determine the autoimmune pattern of depigmentation in the skin. Our study identifies anatomically distinct fibroblasts with permissive or repressive IFNγ responses as the key determinant of body-level patterns of lesions in vitiligo, and highlights mesenchymal subpopulations as therapeutic targets for treating autoimmune diseases.

The Difference in Expression of Autophagy-Related Proteins in Lesional and Perilesional Skin in Adult Patients with Active and Stable Generalized Vitiligo-A Cross-Sectional Pilot Study

Background:

Autophagy plays an important role in maintaining intracellular homeostasis and is essential for cell survival and cell death. Dysfunction of autophagy has been described in many autoimmune diseases but data on vitiligo are scarce.

Aims:

The aim of this pilot study was to investigate the expression of autophagy-related proteins in patients with vitiligo.

Methods:

Western blotting was used to analyze the expression of microtubule-associated protein light chain 3 (LC3II/I), autophagy-related gene 5 (Agt5), mammalian target of rapamycin (mTOR) and p62 in lesional and perilesional vitiligo skin from seven patients with active generalized vitiligo and nine patients with stable generalized vitiligo compared to control skin from six healthy subjects.

Results:

Our data showed increased expression of the autophagy marker LC3II/I and decreased p62 protein expression in lesional skin of active and stable vitiligo compared to control skin (P < 0.01). No significant difference in the expression of LC3II/I and p62 was found in perilesional skin of active vitiligo patients (P > 0.05) compared to control skin. Expression of LC3II/I in stable vitiligo lesional skin was higher and p62 expression was lower compared to active vitiligo lesional skin (P < 0.01). Decreased p62 expression was shown in perilesional skin of stable vitiligo patients (P < 0.05). Agt5 protein in lesional and perilesional skin of both active and stable vitiligo patients were increased (P < 0.01 and P< 0.05) compared to control skin. The expression of mTOR protein in lesional and perilesional skin of active and stable vitiligo patients was significantly lower than in control skin (P < 0.01).

Conclusions:

The present study indicates increased autophagy in lesional skin in vitiligo patients. Stable vitiligo lesional skin showed increased autophagy compared to active vitiligo lesional skin. Missing activation of autophagy in active vitiligo perilesional skin suggests disturbed autophagy to be associated with vitiligo.

Effects of a Traditional Caraway Formulation on Experimental Models of Vitiligo and Mechanisms of Melanogenesis

Background

Kursi Karwiya or caraway tablet (CWT), a traditional medicine formula, is widely used in Xinjiang, China, for treating vitiligo, a common autoimmune disease for which there is currently no satisfactory cure. Clinical interventions include pharmacological treatment with psoralens, often in conjunction with UVA radiation, but toxic side effects limit this application. Studies on the activities and mechanisms of CWT are scarce.

Objective

To investigate the in vitro and in vivo effects of CWT in B16 cell line and in animal models of vitiligo, further exploring its mechanisms of regulating melanogenesis.

Methods

Effects of CWT on melanin synthesis in B16 cells and mushroom tyrosinase activity were investigated in vitro. The signaling pathway of melanogenesis in murine B16 melanoma cells was examined by Western blotting. Two different animal models were used, vitiligo induced by hydroquinone in the mouse model and by hydrogen peroxide in the guinea pig model. Relevant biochemical parameters in blood and skin tissue were measured, and visual inspection, histopathology, and immunohistochemical analysis of treated areas were carried out.

Results

CWT produced changes in biochemical parameters including TYR, MDA, MAO, AChE, IL-6, INF-α, β-EP, and cAMP in blood and/or skin tissue and in regulating melanogenesis. After treatment with CTW, skin color, melanin containing hair follicles, and expression of TYR, TRP-1, and TRP-2 in the skin of animals were significantly affected.

Conclusions

CWT alleviated many of detrimental effects in both models of vitiligo. Tyrosinase activity and melanin content in B16 cells were increased, at least in part, via activation of the PKA p38 MAPK signaling pathways. Our results show that CWT produces beneficial effects on parameters of vitiligo and is worthy of further investigation for use in this distressing autoimmune disorder which currently has no effective cure.

Morin Induces Melanogenesis via Activation of MAPK Signaling Pathways in B16F10 Mouse Melanoma Cells

Morin is a well-known flavonoid, and has been reported to have various properties, such as anti-cell death, antioxidant, and anti-inflammatory properties. Although studies on the biochemical and biological actions of morin have been reported, the melanin biosynthesis effects and molecular mechanisms are unknown. In this study, we first found that morin has the effect of enhancing melanin biosynthesis in B16F10 mouse melanoma cells, and analyzed the molecular mechanism. In this study, we examined the effects of morin on the melanin contents and tyrosinase activity, as well as the protein expression levels of the melanogenic enzymes TRP-1, TRP-2, and microphtalmia-associated transcription factor (MITF) in B16F10 mouse melanoma cells. Morin showed no cytotoxicity in the concentration range of 5–100 μM, and significantly increased the intracellular tyrosinase activity and melanin contents. In mechanism analysis, morin increased the protein expression of TRP-1, TRP-2, and MITF associated with melanogenesis. Furthermore, morin increased phosphorylated ERK and p38 at the early time, and decreased phosphorylated ERK after 12 h. The results suggest that morin enhances melanin synthesis through the MAPK signaling pathways in B16F10 mouse melanoma cells.

MicroRNA-145-5p Protects Human Melanocytes Against Oxidative Damage by Targeting Transient Receptor Potential Melastatin 2 (TRPM2)

Background: Oxidative stress was reported to be involved in the progression of vitiligo. microRNAs (miRNAs) have been confirmed to display critical roles in vitiligo. In this study, we conjectured that miR-145-5p might be related to the development of vitiligo by regulating the key genes expression in melanocytes. Methods: H2O2 was used to induce the dysfunction of melanocytes. The levels of TRPM2 and miR-145-5p in H2O2-induced human primary melanocytes were assessed using reverse transcription-quantitative polymerase chain reaction (RT-qPCR). TargetScan and Dual luciferase reporter gene assay were conducted to confirm the correlation between miR-145-5p and TRPM2. Cell viability and apoptosis were determined using MTT and Flow cytometry analysis. Reactive oxygen species (ROS), antioxidant enzymes superoxide dismutase (SOD) and catalase (CAT) were determined using specific assay kits. The levels of cleaved caspase-3 and pro-Caspase3 were measure by western blotting. Results: TRPM2 was upregulated while miR-145-5p was downregulated in H2O2-induced human primary melanocytes. Dual luciferase reporter assay confirmed that TRPM2 was a target gene of miR-145-5p. miR-145-5p mimic transfection significantly increased cell viability and inhibited cell apoptosis in H2O2-treated melanocytes. In addition, overexpression of miR-145-5p enhanced the antioxidant activity of SOD and CAT, and decreased intracellular ROS accumulation. Notably, these findings were abolished by TRPM2-plasmid. Conclusions: Taken together, our study demonstrated that oxidative stress induced up-regulation of TRPM2 and down-regulation of miR-145-5p in melanocytes. In addition, overexpression of miR-145-5p alleviated melanocytes destruction via targeting TRPM2. These results indicated that miR-145-5p might serve as a potential target for anti-oxidative therapy in vitiligo.

Myron Gordon Award paper: Microbes, T-cell diversity and pigmentation

Melanocytes are static, minimally proliferative cells. This leaves them vulnerable in vitiligo. Yet upon malignant transformation, they form vicious tumors. This profound switch in physiology is accompanied by genetic change and is driven by environmental factors. If UV exposure in younger years supports malignant transformation and melanoma formation, it can likewise impart mutations on melanocytes that reduce their viability, to initiate vitiligo. A wide variety of microbes can influence these diametrically opposed outcomes before either disease takes hold. These microbes are vehicles of change that we are only beginning to study. Once a genetic modification occurs, there is a wide variety of immune cells ready to respond. Though it does not act alone, the T cell is among the most decisive responders in this process. The same biochemical process that offered the skin protection by producing melanin can become an Achilles heel for the cell when the T cells target melanosomal enzymes or, on occasion, neoantigens. T cells are precise, determined, and consequential when they strike. Here, we probe the relationship between the microbiome and its metabolites, epithelial integrity, and the activation of T cells that target benign and malignant melanocytes in vitiligo and melanoma.

Comparative efficacy between localized 308-nm excimer light and targeted 311-nm narrowband ultraviolet B phototherapy in vitiligo: A randomized, single-blind comparison study

BACKGROUND

There are limited data to compare efficacy between recent 308-nm excimer and conventional 311-nm narrowband ultraviolet B (NB-UVB) light in the treatment of vitiligo.

OBJECTIVE

To compare efficacy between 308-nm excimer light and 311-nm NB-UVB in patients with symmetrical vitiligo lesions.

METHODS

Thirty-six symmetrically paired vitiligo lesions on the same anatomical area were enrolled. One side of the symmetrical lesions was treated with localized 308-nm excimer light, and the opposite side was treated with targeted 311-nm NB-UVB assigned randomly by computer. All lesions were treated with the same protocol, for 48 sessions. Repigmentation was evaluated using Vitiligo Area Scoring Index (VASI) and grading the repigmentation was carried out with three independent investigators.

RESULTS

Thirty-six symmetrically vitiligo lesions were randomly treated, one side with 308-nm excimer light and the opposite side with 311-nm NB-UVB. After 48 sessions, a significantly lower VASI score and a higher grade of repigmentation were observed in 308-nm excimer light-treated side (P < .001). Nine lesions (25%) treated with 308-nm excimer light and only five lesions (13.89%) treated with 311-nm NB-UVB achieved excellent repigmentation. The 308-nm excimer light and 311-nm NB-UVB-treated sides rapidly obtained 25% repigmentation within a mean of 19.42 sessions and 26.25 sessions, respectively (P = .002). There was no significant difference in mean cumulative UV dosage (P = .065). Side effect as phototoxicity was similar in both sides (P = .08).

CONCLUSION

Localized 308-nm excimer light appears to be more effective and also more rapidly induces repigmentation than targeted 311-nm NB-UVB for treatment of vitiligo.

Increased expression of Toll-like receptor 7 and 9 in vitiligo melanocytes: a pilot study

BACKGROUND

Toll-like receptors (TLRs) are expressed on human melanocytes, and play an important role in innate and acquired immunity. The role of TLRs in the pathogenesis of vitiligo has not been fully described.

AIM

To investigate the expression of TLRs in melanocytes from patients with vitiligo and healthy controls (HCs).

METHODS

Primary cultured vitiligo and control melanocytes were obtained from perilesional normal skin of patients with generalized vitiligo and HCs. TLRs mRNA expression in melanocytes were determined by real-time reverse transcription PCR and protein expression by western blotting. Apoptosis was analysed using an annexin V-fluorescein isothiocyanate apoptosis detection kit, and tyrosinase activity and melanin content were measured by a modified dopachrome and colorimetric method. Interleukin (IL)-6, IL-8 and soluble cell adhesion molecule (sICAM)-1 expression were measured by ELISA.

RESULTS

In vitiligo melanocytes, compared with control melanocytes, apoptosis rate, expression of TLR7 and TLR9 mRNA and protein, and production of IL-8, IL-6 and sICAM-1 were significantly increased, whereas tyrosinase activity and melanin content were significantly decreased.

CONCLUSIONS

Our results suggest that the increased expression of TLR7 and TLR9 might correlate with melanocyte dysfunction in vitiligo.

Mechanisms of microbial pathogenesis and the role of the skin microbiome in psoriasis: A review

The pathogenesis of psoriasis may involve a breakdown of immune tolerance to cutaneous microorganisms. Psoriasis is associated with a higher incidence of Crohn disease and periodontitis, two diseases involving impaired tolerance and abnormal immune activation in response to intestinal and oral microbiota, respectively. In addition, guttate and chronic plaque psoriasis are associated with Streptococcus pyogenes colonization. The aim of this review is to characterize the microorganisms implicated in psoriasis by examining results of major association studies and possible mechanisms of pathogenesis. Although studies show relative increases in Streptococcus and Staphylococcus and decreases in Malassezia and Cutibacterium, they differ in methods of sampling and methods of microbial analysis. As such, no definitive associations between microbes and psoriasis have been found to date. It also remains unclear if changes in the microbiomal composition have a causal association with psoriasis or are simply a consequence of the inflammatory microenvironment. Techniques enabling strain-level analysis rather than species-level analysis of the skin microbiome are likely necessary to determine microbiomal signatures of psoriasis. Future investigations may lead to new diagnostic tests and novel treatments, such as probiotics or bacterial transplantation.

Ephedra gerardiana aqueous ethanolic extract and fractions attenuate Freund Complete Adjuvant induced arthritis in Sprague Dawley rats by downregulating PGE2, COX2, IL-1β, IL-6, TNF-α, NF-kB and upregulating IL-4 and IL-10

ETHNOPHARMACOLOGICAL RELEVANCE

The whole plant, roots and stems of Ephedra gerardiana (Family Ephedraceae) have long been used as a folk remedy to treat rheumatism and painful joints in Northern Areas of Pakistan.

AIM OF THE STUDY

The purpose of study was to observe the preventive efficacy of Ephedra gerardiana (EG) aerial parts in treating rheumatoid arthritis using Freund's complete adjuvant (FCA) induced arthritis in rat model and to determine its possible mechanism of action.

MATERIAL AND METHODS

Arthritis was induced in Sprague Dawley rats by immunization with 0.1 ml FCA in left footpad. EG aqueous ethanolic extract (30:70) and its aqueous, n-butanol and ethyl acetate fractions at 200 mg/kg were orally administered from day 0, 30 min prior to adjuvant injection and sustained for 28 days. Paw volume/diameter, arthritic score, body weight, and hematological (WBC, RBC, ESR, Hb and Platelet count) and biochemical (AST, ALT, ALP, urea, creatinine, CRP and RF) parameters were observed. The mRNA expression levels of COX-2, IL-1β, IL-6, NF-kB, TNF-α, IL-4 and IL-10 were measured by real time reverse transcription polymerase chain reaction (RT-PCR) while, PGE2 and TNF-α levels in serum samples were measured by Enzyme linked immunosorbent assay (ELISA). Moreover, radiographs of hind paws and histological changes in ankle joint were analyzed in adjuvant injected rats. In addition, anti-oxidant activity of plant extract and fractions was also evaluated using DPPH and reducing power assays. Also, preliminary phytochemistry and total phenolic and flavonoid contents were investigated in most active fraction (aqueous fraction).

RESULTS

EG extract and fractions (notably aqueous fraction) significantly suppressed paw swelling and arthritic score, prevented cachexia and remarkably ameliorated hematological and biochemical changes. Furthermore, the overproduction of PGE2, COX-2, IL-1β, IL-6, NF-kB and TNF-α were remarkably attenuated in all EG treated rats, however, IL-4 and 10 were markedly increased. The radiographic and histopathologic improvement in joint architecture was also observed in EG treated rats. Piroxicam, used as reference drug, also significantly suppressed arthritis. Additionally, plant exhibited notable anti-oxidant activity and phytochemical analysis revealed the presence of alkaloids, flavonoids, phenols, tannins, saponins and glycosides.

CONCLUSION

These results indicate that EG extract and fractions significantly attenuated adjuvant arthritis in rats by decreasing the levels of aforementioned pro-inflammatory and increasing the levels of anti-inflammatory mediators. This suggests that Ephedra gerardiana aerial parts might be used as a therapeutic agent for treating human arthritis.

Novel Furocoumarin Derivatives Stimulate Melanogenesis in B16 Melanoma Cells by Up-Regulation of MITF and TYR Family via Akt/GSK3β/β-Catenin Signaling Pathways

The extracts of Ficuscarica L. and Psoralen corylifolia L. are traditional Uygur medicines for the treatment of vitiligo, and its active ingredients furocoumarins, were are found to be the most effective agents against this skin disorder nowadays. Therefore, a series of novel easter derivatives (8a-8p) of furocoumarin were designed and synthesized based on our previous research to improve this activity in the present study. The synthesized derivatives were biologically evaluated for melanin synthesis in murine B16 cells and the SAR (structure-activity relationship) was summarized. Eight derivatives were more potent than positive control (8-MOP, 8-methoxypsoralan), especially compounds 8n (200%) and 8o (197%), which were nearly 1.5-fold potency when compared with 8-MOP (136%). Furthermore, the signaling pathway by which 8n activates the melanin biosynthesis was defined. Our results showed that it not only elevated the melanin content, but also stimulated the activity of tyrosinasein a concentration-dependent manner. Increasing of phosphorylation of Akt (also named PKB, protein kinase B) and non-activated GSK3β (glycogen synthase kinase 3 beta), which inhibited the degradation of β-catenin were observed through Western blot analysis. The accumulation of β-catenin probably led to the activation of transcription of MITF (microphthalmia-associated transcription factor) and TYR (tyrosinase) family, as well as the subsequent induction of melanin synthesis.

The catalase gene promoter and 5'-untranslated region variants lead to altered gene expression and enzyme activity in vitiligo

BACKGROUND

Oxidative stress is considered to be the initial event in the course of vitiligo. The enzyme catalase (CAT) is mainly involved in cellular defence against oxidizing agents through detoxifying H2 O2 .

OBJECTIVES

The aims were (i) to assess erythrocyte CAT enzyme activity and lipid peroxidation (LPO) levels as well as CAT mRNA expression in skin and blood; (ii) to investigate CAT gene promoter rs7943316, rs1001179, 5'-untranslated region rs1049982, and exon (rs17886350, rs11032709, rs17880442, rs35677492) polymorphisms; and (iii) to perform genotype/haplotype-phenotype correlation analyses in patients with vitiligo and controls from Gujarat.

METHODS

CAT activity and LPO levels were measured spectrophotometrically. CAT mRNA levels were estimated using real-time polymerase chain reaction (PCR) by the SYBR Green method. Single-nucleotide polymorphism genotyping was performed using PCR-restriction fragment length polymorphism and amplification-refractory mutation system-PCR analyses.

RESULTS

Patients with vitiligo showed significantly decreased CAT mRNA expression in lesional and nonlesional skin and in blood, with reduced CAT activity compared with that of controls. CAT -89A/T and -20T/C polymorphisms were significantly associated with patients, especially with active and generalized vitiligo, whereas no association was observed for -262G/A and exon polymorphisms. The A-262 T-89 C-20 haplotype with variant alleles was found to be associated with 6·4-fold risk of vitiligo. Genotype/haplotype-phenotype correlation analyses revealed that individuals with susceptible genotypes/haplotype for CAT -89A/T and -20T/C polymorphisms showed significantly decreased CAT mRNA/activity, and only -89A/T polymorphisms showed significantly increased LPO levels compared with wild-type genotypes/haplotype.

CONCLUSIONS

The present study proposes the crucial role of CAT and its allelic variants in oxidative stress-mediated pathogenesis of vitiligo.

An Isoxazole Chalcone Derivative Enhances Melanogenesis in B16 Melanoma Cells via the Akt/GSK3β/β-Catenin Signaling Pathways

Plants or plant-derived products have been routinely used in several traditional medicine systems for vitiligo treatment. It is well-known that melanogenesis can be promoted by certain flavonoid compounds isolated from the traditional Uyghur medicinal plant, Kaliziri. Therefore, Chalcones, one class of flavonoid compounds, has become an interesting target for the development of anti-vitiligo agents. A series of novel isoxazole chalcone derivatives have been designed, synthesized, and evaluated for biological activities by our group. Among them, derivative 1-(4-((3-phenylisoxazol-5-yl)methoxy)phenyl)-3-phenylprop-2-en-1-one (PMPP) was identified as a potent tyrosinase activator with better activity and lower toxicity than the positive control 8-methoxypsoralen (8-MOP) in this study. Further investigations revealed that Akt and GSK3β were the signaling pathways involved in the hyperpigmentation of PMPP. Overall, these studies may provide a convenient and novel approach for the further development of anti-vitiligo agents.

Effects of Extremely Low Frequency Electromagnetic Fields on Melanogenesis through p-ERK and p-SAPK/JNK Pathways in Human Melanocytes

This study evaluated frequency-dependent effects of extremely low frequency electromagnetic fields (ELF-EMFs) on melanogenesis by melanocytes in vitro. Melanocytes were exposed to 2 mT EMFs at 30-75 Hz for 3 days before melanogenesis was examined. Exposure to ELF-EMFs at 50 and 60 Hz induced melanogenic maturation without cell damage, without changing cell proliferation and mitochondrial activity. Melanin content and tyrosinase activity of cells exposed to 50 Hz were higher than in controls, and mRNA expression of tyrosinase-related protein-2 was elevated relative to controls at 50 Hz. Phosphorylated cyclic adenosine monophosphate response element-binding protein (p-CREB) levels were higher than controls in cells exposed to ELF-EMFs at 50-75 Hz. Immunohistochemical staining showed that melanocyte-specific markers (HMB45, Melan-A) were strongly expressed in cells exposed to EMFs at 50 and 60 Hz compared to controls. Thus, exposure to ELF-EMFs at 50 Hz could stimulate melanogenesis in melanocytes, through activation of p-CREB and p-p38 and inhibition of phosphorylated extracellular signal-regulated protein kinase and phosphorylated stress-activated protein kinase/c-Jun N-terminal kinase. The results may form the basis of an appropriate anti-gray hair treatment or be applied in a therapeutic device for inducing repigmentation in the skin of vitiligo patients.

Upregulation of Melanogenesis and Tyrosinase Activity: Potential Agents for Vitiligo

Melanin, the compound primarily responsible in humans for hair, eye and skin pigmentation, is produced by melanocytes through a complicated process called melanogenesis that is catalyzed by tyrosinase and other tyrosinase-related proteins. The abnormal loss of melanin causes dermatological problems such as vitiligo. Hence the regulation of melanogenesis and tyrosinase activity is very important for treating hypopigmentary disorders. Many melanogenesis stimulators have been discovered during the past decade. This article reviews recent advances in research on extracts and active ingredients of plants, synthesized compounds with stimulating effect on melanin synthesis and tyrosinase activity, as well as their influence on the expression of related proteins and possible signaling pathways for the design and development of novel anti-vitiligo agents.

Prevalence and Clinical Characteristics of Itch in Vitiligo and Its Clinical Significance

Objective

Vitiligo usually presented as asymptomatic depigmented macules and patches. Little is known regarding itch in vitiligo. This study aimed to evaluate the prevalence and characteristics of itch in vitiligo patients.

Patients and Methods

A cross-sectional study was conducted on vitiligo patients. Itch character and intensity were determined through questionnaires. Evaluation was also made by dermatologists to define vitiligo subtype, body surface area, Koebner phenomenon (KP), and so on. Data were assessed by computer software. Results were considered statistically significant if p < 0.05.

Results

Among 402 patients, itch on vitiliginous lesion presented in 20.2%. Prevalence of itch was most common in focal vitiligo (29.4%), followed by segmental vitiligo (20.3%) and nonsegmental vitiligo (19.6%), respectively. Tingling sensation was the most common itch-related symptom (82.7%). The median itch intensity is 5 by 10-point visual analog scale. Daily activity and sleep disturbance were observed in 60.5% and 39.5% of patients who experience itch. Itch occurred approximately 3 days prior to the development of lesions in 48.1% of patients. Thirty-two patients (78.1%) with both itch and KP type IIb had active disease.

Conclusions

Itch in vitiligo is not uncommon. The presence of itch with KP type IIb may warrant the active vitiligo.

Comparison Between (311-312 nm) Narrow Band Ultraviolet-B Phototherapy and (308 nm) Monochromatic Excimer Light Phototherapy in Treatment of Vitiligo: A Histopathological Study

Introduction: Recently, the monochromatic excimer light (MEL) of 308 nm wavelength has shown some advantages in comparison to narrow band ultraviolet B (NB-UVB) for the treatment of vitiligo. To histopathologically compare the early effects of NB-UVB and 308-nm MEL phototherapy on vitiliginous patches using H&E and HMB-45. Methods: Thirty subjects with non-segmental vitiligo lesions were treated twice a week for 6 weeks with 308-nm MEL, while NB-UVB was used to treat lesions contra laterally. Skin biopsies were taken from lesional areas before and after 6 weeks of treatment by either modality. It was prepared for light microscopy and immunohistochemical study (HMB-45). This study was performed as a clinical trial (Trial registration: http://www.pactr.org; Identifier: PACTR201705002279419) Results: All lesions before treatment had labeling index (number of pigmented cells/non-pigmented cells) of 0.0 (0%). After treatment the LI for MEL was 4.2 ± 2.6, while for NB-UVB LI it was 0.3 ± 0.7. MEL showed higher statistical significance regarding increase of basal pigmented cells, and significant decrease in vacuolated keratinocytes and basal membrane thickness than NB-UVB. Conclusion: Although NB-UVB is considered as treatment of choice for vitiligo, MEL is acknowledged as an effective treatment modality for vitiliginous lesions that induces more repigmentation than NB-UVB, and more rapidly, as confirmed by our study.

Protective effect of madecassoside on H2O2-induced oxidative stress and autophagy activation in human melanocytes

Background

Centella asiatica (L.) Urb. is a traditional Chinese medicine that has many medical applications, including wound healing and anti-oxidation. Some traditional Chinese Medicine doctors have found that it has therapeutic effects for external use in the repigmentation of vitiligo and post-inflammatory hypopigmentation. This study was designed to evaluate the effects of madecassoside, a major bioactive component of C. asiatica, on oxidative stress in human melanocytes and its possible mechanism of action.

Results

In H2O2-induced oxidative conditions, madecassoside inhibited melanocyte dendrite retraction, improved MMP and reduced the accumulation of [Ca2+]i in a concentration-dependent manner. Observations by TEM showed that madecassoside attenuated the damage of mitochondria in human melanocytes caused by oxidative stress. Furthermore, autophagy activation was demonstrated by AO staining and an increased LC3-II/LC3-I ratio.

Materials and Methods

Normal human melanocytes were treated with 0.01 mM H2O2 and varying concentrations of madecassoside (0, 10, 50, 100 μg/mL). Subsequently, the retraction velocity of melanocyte dendrites was assessed. Determination of mitochondrial membrane potential (MMP, ΔΨm) was performed by flow cytometry and intracellular calcium ([Ca²⁺]i) level were measured. Alterations of mitochondrial ultrastructure were observed by transmission electron microscopy (TEM). Acridine orange (AO) staining was used to measure autophagy. The LC3-II/LC3-I ratio, an indicator of autophagosome formation, was analyzed by western blot.

Conclusions

These results demonstrate the antioxidative effect of madecassoside on human melanocytes subjected to oxidative damage via the activation of autophagy. Moreover, madecassoside could be a promising treatment for vitiligo mainly caused by oxidative stress.

Detection of auto antibodies and transplantation of cultured autologous melanocytes for the treatment of vitiligo

The aim of the present study was to establish an immunofluorescence method of antibody detection to identify melanocytes in the serum of vitiligo patients. Furthermore, we aimed to establish a method for the culture and proliferation of autologous pure melanocytes and to observe the effect of their transplantation for the treatment of vitiligo. Suspension of epidermal cells with melanocytes was performed using trypsin digestion of normal epiderm from eyelid operation and melanocytes were selectively cultured and proliferated in serum-free M2 medium. FITC-labeled rabbit anti-human antibody was used to detect the relative fluorescence intensity of the melanocytes. After identification with immunological and biological examinations, the melanocytes were transplanted to depigmented areas of vitiligo. Repigmentation was observed continuously. The results indicated that melanocytes could be selectively proliferated in the medium. Subsequently, pure melanocytes without contamination of fibroblast and keratinocyte were harvested. A total of 34 patients suffering vitiligo for between 3 months and 20 years with depigmented area (between 4 cm² and 70% of body surface) were divided into 19 cases of developing stage and 15 cases of stable stage, according to the change of depigmentation. A total of 15 developing cases were positive for the antibody against melanocytes, with the positive rate of 79%. The titers of serum was >1:50 in 10 patients at the developing stage, and 5 developing patients were 1:10. Among the 15 stable cases, four were positive, with a positive rate of 27%. Fluorescence of antibody was localized in the cytoplasm of the melanocytes. Autologous melanocytes of vitiligo patients could be selectively proliferated in the medium. Next, pure melanocytes without contamination with fibroblasts and keratinocytes were harvested. A total of 16 vitiligo patients with 28 depigmented areas (2–200 cm²) were treated with transplantation of melanocytes. Repigmentation of the transplanted areas appeared as red coloration after one month. All the vitiligous areas received transplantation were repigmented significantly with hypo- or hyper-pigmentation after 3–5 months. After 6–8 months, 87.5% of lesions showed repigmentation of >50% of the lesion area. No scarring or other side-effects occurred. After follow-up of 5 years, no relapse was observed in transplantation area. Thus, an immunofluorescence method for the test of antibody to melanocytes in the serum of vitiligo patients was established. Transplantation of cultured autologous melanocytes was an effective and safe measure for treatment of vitiligo, particularly for patients with a large depigmented area.

Dysfunction of Autophagy: A Possible Mechanism Involved in the Pathogenesis of Vitiligo by Breaking the Redox Balance of Melanocytes

Vitiligo is a common chronic acquired pigmentation disorder characterized by loss of functional melanocytes from the epidermis and follicular reservoir. Among multiple hypotheses which have been proposed in the pathogenesis of vitiligo, autoimmunity and oxidative stress-mediated toxicity in melanocytes remain most widely accepted. Macroautophagy is a lysosome-dependent degradation pathway which widely exists in eukaryotic cells. Autophagy participates in the oxidative stress response in many cells, which plays a protective role in preventing damage caused by oxidative stress. Recent studies have enrolled autophagy as an important regulator in limiting damage caused by UV light and lipid oxidation, keeping oxidative stress in a steady state in epidermal keratinocytes and maintaining normal proliferation and aging of melanocytes. Impairment of autophagy might disrupt the antioxidant defense system which renders melanocytes to oxidative insults. These findings provide supportive evidence to explore new ideas of the pathogenesis of vitiligo and other pigmentation disorders.

Identification of Novel HLA-A*0201-Restricted CTL Epitopes in Chinese Vitiligo Patients

Generalized vitiligo is an autoimmune disease characterized by melanocyte loss, which results in patchy depigmentation of skin and hair. Recent studies suggested the key role of CD8⁺T lymphocytes for mediating immune response in vitiligo through melanocyte differentiation antigens, including tyrosinase, gp100 and MelanA/Mart-1. However, the specific epitopes of these auto-antigens are still unknown. In our study, we predicted the possible HLA-A*0201-restricted nonapeptides overlaying the full-length amino acid sequences of these three known antigens and investigated the lymphocytes reactivity to these nonapeptides by Elispot assay. In addition, we evaluated the abilities of these nonapeptides to activate CD8⁺T cells. We screened out 5 possible epitopes originated from tyrosinase and gp100, numbered P28, P41, P112, P118 and P119. Among these 5 epitopes, notably, P28 and P119 played the dominant role in activating CTLs, with a significant increase in proliferation rate and Interferon-γ (IFN-γ) production of CD8⁺T cells. Nevertheless, antigen-specific T cell reactivity was not detected in MelanA/Mart-1 peptides. Our studies identified two novel epitopes originated from proteins of gp100 and tyrosinase, which may have implications for the development of immunotherapies for vitiligo.

Synthesis and biological evaluation of furocoumarin derivatives on melanin synthesis in murine B16 cells for the treatment of vitiligo

Furocoumarins, isolated from Psoralen corylifolia L., were found to be the most effective drug in the treatment of vitiligo nowadays. Twenty-five furocoumarin derivatives were thus designed and synthesized in order to improve the melanogenesis in B16 cells for the first time. Among them, twenty-three compounds were more potent than the positive control (8-MOP), the commonly used drug for vitiligo in clinic. Noticeably, compounds 6m (350.5%) and 6p (313.1%) based on the scaffold of 6k (2H-benzofuro[2,3-h]chromen-2-one) were nearly 3-fold stronger than 8-MOP (114.50%). The in vitro melanin synthesis evaluation of these structurally diverse analogues had also led to an outline of structure-activity relationship.

Systematic understanding the mechanisms of vitiligo pathogenesis and its treatment by Qubaibabuqi formula

ETHNOPHARMACOLOGICAL RELEVANCE

Vitiligo is a depigmentation disorder, which results in substantial cosmetic disfigurement and poses a detriment to patients' physical as well as mental. Now the molecular pathogenesis of vitiligo still remains unclear, which leads to a daunting challenge for vitiligo therapy in modern medicine. Herbal medicines, characterized by multi-compound and multi-target, have long been shown effective in treating vitiligo, but their molecular mechanisms of action also remain ambiguous.

MATERIALS AND METHODS

Here we proposed a systems pharmacology approach using a clinically effective herb formula as a tool to detect the molecular pathogenesis of vitiligo. This study provided an integrative analysis of active chemicals, drug targets and interacting pathways of the Uygur medicine Qubaibabuqi formula for curing Vitiligo.

RESULTS

The results show that 56 active ingredients of Qubaibabuqi interacting with 83 therapeutic proteins were identified. And Qubaibabuqi probably participate in immunomodulation, neuromodulation and keratinocytes apoptosis inhibition in treatment of vitiligo by a synergistic/cooperative way.

CONCLUSIONS

The drug-target network-based analysis and pathway-based analysis can provide a new approach for understanding the pathogenesis of vitiligo and uncovering the molecular mechanisms of Qubaibabuqi, which will also facilitate the application of traditional Chinese herbs in modern medicine.

Hashimoto's thyroiditis could be secondary to vitiligo: the possibility of antigen crossover and oxidative stress between the two diseases

Autoimmune thyroid diseases (AITDs) are often accompanied by vitiligo, and the sera of patients with vitiligo often demonstrate increased frequencies of thyroid autoantibodies. In this study, we investigated the expression of melanocyte-associated antigens in tissues from patients with Hashimoto's thyroiditis (HT) without vitiligo using immunohistochemistry. Tissues of HT without vitiligo, as well as normal thyroid tissues, were both negative for the expression of NKI/beteb, gp100, tyrosinase-related protein 1 (TRP1), HMB-45 and S100, whereas they were positive for the expression of tyrosinase-related protein 2 (TRP2), lysosome-associated membrane protein 1 (LAMP1) and CD69. Tyrosinase (TYR) was only detected in tissues of HT, and levels of LAMP1 and CD69 were higher in tissues of HT than in normal thyroid tissues (p < 0.005). These results suggest the possibility of antigen crossover and oxidative stress between vitiligo and HT that might represent an immunological basis for secondary HT associated with vitiligo.

Vitiligo: interplay between oxidative stress and immune system

Vitiligo is a multifactorial polygenic disorder with a complex pathogenesis, linked with both genetic and non-genetic factors. The precise modus operandi for vitiligo pathogenesis has remained elusive. Theories regarding loss of melanocytes are based on autoimmune, cytotoxic, oxidant-antioxidant and neural mechanisms. Reactive oxygen species (ROS) in excess have been documented in active vitiligo skin. Numerous proteins in addition to tyrosinase are affected. It is possible that oxidative stress is one among the main principal causes of vitiligo. However, there also exists ample evidence for altered immunological processes in vitiligo, particularly in chronic and progressive conditions. Both innate and adaptive arms of the immune system appear to be involved as a primary event or as a secondary promotive consequence. There is speculation on the interplay, if any, between ROS and the immune system in the pathogenesis of vitiligo. The article focuses on the scientific evidences linking oxidative stress and immune system to vitiligo pathogenesis giving credence to a convergent terminal pathway of oxidative stress-autoimmunity-mediated melanocyte loss.

Role of keratinocytes in the development of vitiligo

Vitiligo is an acquired depigmentary disorder of the skin that results from the loss of functioning epidermal melanocytes. Most studies on vitiligo have concentrated on the abnormality of melanocytes rather than the abnormality of keratinocytes; however, epidermal melanocytes form a functional and structural unit with neighboring keratinocytes. In fact, direct cell-to cell contact stimulates in vitro proliferation of melanocytes, and growth factors produced by adjacent keratinocytes regulate the proliferation and differentiation of melanocytes. The potential role of keratinocyte-derived cytokines has also been presented. We focused on the structural changes in vitiliginous keratinocytes, which may result in loss of melanocytes, to examine the pathomechanism of vitiligo. The results of a comparison between depigmented and normally pigmented epidermis in patients with vitiligo showed that the keratinocytes in the depigmented epidermis were more vulnerable to apoptosis. Impaired Phosphatidylinositol 3-kinase (PI3K)/serine/threonine protein kinase (Akt) activation followed by reduced nuclear factor-κB activation under increased tumor necrosis factor-α levels was demonstrated as a mechanism for keratinocyte apoptosis. The role of aquaporin 3 in keratinocyte apoptosis was addressed based on the relationship between the PI3K/AKT pathway and the E-cadherin-catenin complex. Apoptotic keratinocytes induced a lower expression of keratinocyte-derived factors, including stem cell factor, in depigmented epidermis, resulting in passive melanocyte death.

Assessment methods for the evaluation of vitiligo

There is no standardized method for assessing vitiligo. In this article, we review the literature from 1981 to 2011 on different vitiligo assessment methods. We aim to classify the techniques available for vitiligo assessment as subjective, semi-objective or objective; microscopic or macroscopic; and as based on morphometry or colorimetry. Macroscopic morphological measurements include visual assessment, photography in natural or ultraviolet light, photography with computerized image analysis and tristimulus colorimetry or spectrophotometry. Non-invasive micromorphological methods include confocal laser microscopy (CLM). Subjective methods include clinical evaluation by a dermatologist and a vitiligo disease activity score. Semi-objective methods include the Vitiligo Area Scoring Index (VASI) and point-counting methods. Objective methods include software-based image analysis, tristimulus colorimetry, spectrophotometry and CLM. Morphometry is the measurement of the vitiliginous surface area, whereas colorimetry quantitatively analyses skin colour changes caused by erythema or pigment. Most methods involve morphometry, except for the chromameter method, which assesses colorimetry. Some image analysis software programs can assess both morphometry and colorimetry. The details of these programs (Corel Draw, Image Pro Plus, AutoCad and Photoshop) are discussed in the review. Reflectance confocal microscopy provides real-time images and has great potential for the non-invasive assessment of pigmentary lesions. In conclusion, there is no single best method for assessing vitiligo. This review revealed that VASI, the rule of nine and Wood's lamp are likely to be the best techniques available for assessing the degree of pigmentary lesions and measuring the extent and progression of vitiligo in the clinic and in clinical trials.

HSP70i is a critical component of the immune response leading to vitiligo

HSP70i and other stress proteins have been used in anti-tumor vaccines. This begs the question whether HSP70i plays a unique role in immune activation. We vaccinated inducible HSP70i (Hsp70-1) knockout mice and wild-type animals with optimized TRP-1, a highly immunogenic melanosomal target molecule. We were unable to induce robust and lasting depigmentation in the Hsp70-1 knockout mice, and in vivo cytolytic assays revealed a lack of cytotoxic T-lymphocyte activity. Absence of T-cell infiltration to the skin and maintenance of hair follicle melanocytes were observed. By contrast, depigmentation proceeded without interruption in mice lacking a tissue-specific constitutive isoform of HSP70 (Hsp70-2) vaccinated with TRP-2. Next, we demonstrated that HSP70i was necessary and sufficient to accelerate depigmentation in vitiligo-prone Pmel-1 mice, accompanied by lasting phenotypic changes in dendritic cell subpopulations. In summary, these studies assign a unique function to HSP70i in vitiligo and identify HSP70i as a targetable entity for treatment.