BACKGROUND: Increasing evidence indicates that oxidative stress and interferon γ (IFNγ)-driven cellular immune responses are responsible for the pathogenesis of vitiligo. However, the connection between oxidative stress and the local production of IFNγ in early vitiligo remains unexplored. The aim of this study was to identify the mechanism underlying the production of IFNγ by mast cells and its impact on vitiligo pathogenesis. METHODS: Skin specimens from the central, marginal, and perilesional skin areas of active vitiligo lesions were collected to characterize changes of mast cells, CD8 + T cells, and IFNγ-producing cells. Cell supernatants from hydrogen peroxide (H 2 O 2 )-treated keratinocytes (KCs) were harvested to measure levels of soluble stem cell factor (sSCF) and matrix metalloproteinase (MMP)-9. A murine vitiligo model was established using Mas-related G protein-coupled receptor-B2 (MrgB2, mouse ortholog of human MrgX2) conditional knockout (MrgB2 -/- ) mice to investigate IFNγ production and inflammatory cell infiltrations in tail skin following the challenge with tyrosinase-related protein (Tyrp)-2 180 peptide. Potential interactions between the Tyrp-2 180 peptide and MrgX2 were predicted using molecular docking. The siRNAs targeting MrgX2 and the calcineurin inhibitor FK506 were also used to examine the signaling pathways involved in mast cell activation. RESULTS: IFNγ-producing mast cells were closely aligned with the recruitment of CD8 + T cells in the early phase of vitiligo skin. sSCF released by KCs through stress-enhanced MMP9-dependent proteolytic cleavage recruited mast cells into sites of inflamed skin (Perilesion vs . lesion, 13.00 ± 4.00/high-power fields [HPF] vs . 26.60 ± 5.72/HPF, P <0.05). Moreover, IFNγ-producing mast cells were also observed in mouse tail skin following challenge with Tyrp-2 180 (0 h vs . 48 h post-recall, 0/HPF vs . 3.80 ± 1.92/HPF, P <0.05). The IFNγ + mast cell and CD8 + T cell counts were lower in the skin of MrgB2 -/- mice than in those of wild-type mice (WT vs . KO 48 h post-recall, 4.20 ± 0.84/HPF vs . 0.80 ± 0.84/HPF, P <0.05). CONCLUSION Mast cells activated by MrgX2 serve as a local IFNγ producer that bridges between innate and adaptive immune responses against MCs in early vitiligo. Targeting MrgX2-mediated mast cell activation may represent a new strategy for treating vitiligo.
Vitiligo/metabolism* ; Mast Cells/immunology* ; Animals ; Interferon-gamma/metabolism* ; Mice ; Humans ; Melanocytes/metabolism* ; Receptors, G-Protein-Coupled/genetics* ; Mice, Knockout ; Mice, Inbred C57BL ; Male ; Female ; Matrix Metalloproteinase 9/metabolism* ; Stem Cell Factor/metabolism*

Nigella sativa L. seeds have been traditionally utilized in Chinese folk medicine for centuries to treat vitiligo. This study revealed that the ethanolic extract of Nigella sativa L. (HZC) enhances melanogenesis and mitigates oxidative stress-induced cellular senescence and dysfunction in melanocytes. In accordance with established protocols, the ethanol fraction from Nigella sativa L. seeds was extracted, concentrated, and lyophilized to evaluate its herbal effects via 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assays, tyrosinase activity evaluation, measurement of cellular melanin contents, scratch assays, senescence-associated β-galactosidase (SA-β-gal) staining, enzyme-linked immunosorbent assay (ELISA), and Western blot analysis for expression profiling of experimentally relevant proteins. The results indicated that HZC significantly enhanced tyrosinase activity and melanin content while notably increasing the protein expression levels of Tyr, Mitf, and gp100 in B16F10 cells. Furthermore, HZC effectively mitigated oxidative stress-induced cellular senescence, improved melanocyte condition, and rectified various functional impairments associated with melanocyte dysfunction. These findings suggest that HZC increases melanin synthesis in melanocytes through the activation of the MAPK, PKA, and Wnt signaling pathways. In addition, HZC attenuates oxidative damage induced by H₂O₂ therapy by activating the nuclear factor E2-related factor 2-antioxidant response element (Nrf2-ARE) pathway and enhancing the activity of downstream antioxidant enzymes, thus preventing premature senescence and dysfunction in melanocytes.
Oxidative Stress/drug effects* ; Melanocytes/cytology* ; Cellular Senescence/drug effects* ; Nigella sativa/chemistry* ; Plant Extracts/pharmacology* ; Seeds/chemistry* ; Mice ; Animals ; Melanins/metabolism* ; Monophenol Monooxygenase/metabolism* ; Humans

Humans ; Melanocytes ; Melanosis ; Fibroblasts ; Skin

Keloids are a common type of pathological scar as a result of skin healing, which are extremely difficult to prevent and treat without recurrence. The pathological mechanism of keloids is the excessive proliferation of fibroblasts, which synthesize more extracellular matrices (ECMs), including type I/III collagen (COL-1/3), mucopolysaccharides, connective tissue growth factor (CTGF, also known as cellular communication network factor 2 (CCN2)), and fibronectin (FN) in scar tissue, mostly through the abnormal activation of transforming growth factor-‍β (TGF-‍β)/Smads pathway (Finnson et al., 2013; Song et al., 2018). Genetic factors, including race and skin tone, are considered to contribute to keloid formation. The reported incidence of keloids in black people is as high as 16%, whereas white people are less affected. The prevalence ratio of colored people to white people is 5:1‍‍-‍‍15:1 (Rockwell et al., 1989; LaRanger et al., 2019). In addition, keloids have not been reported in albinism patients of any race, and those with darker skin in the same race are more likely to develop this disease (LaRanger et al., 2019). Skin melanocyte activity is significantly different among people with different skin tones. The more active the melanocyte function, the more melanin is produced and the darker the skin. Similarly, in the same individual, the incidence of keloids increases during periods when melanocytes are active, such as adolescence and pregnancy. Keloids rarely appear in areas where melanocytes synthesize less melanin, such as in the palms and soles. Thus, the formation of keloids seems to be closely related to melanocyte activity.
Adolescent ; Cells, Cultured ; Exosomes/metabolism* ; Fibroblasts/metabolism* ; Humans ; Keloid/pathology* ; Melanins/metabolism* ; Melanocytes/pathology* ; Pilot Projects ; Skin/metabolism* ; Transforming Growth Factor beta/metabolism*

Increasing evidence suggests that stress may induce changes in hair color, with the underlying mechanism incompletely understood. In this study, female C57BL/6 mice subjected to electric foot shock combined with restraint stress were used to build chronic stress mouse model. The melanin contents and tyrosinase activity were measured in mouse skin and B16F10 melanoma cells. The enzyme-linked immunosorbent assay (ELISA) was used to determine the content of tumor necrosis factor α (TNF-α), interleukin- 1β (IL-1β) and interleukin-6 (IL-6) in the mouse skin. The content of nuclear factor κB (NFκB)/p65 subunit in mouse skins was valued by immunofluorescence staining. The results demonstrated that under chronic stress, the fur color turned from dark to brown in C57BL/6 mice due to the decrease of follicle melanocytes and tyrosinase activity in C57BL/6 mouse skin. Simultaneously, inflammatory responses in skins were detected as shown by increased NFκB activity and TNF-α expression in stressed mouse skin. In cultured B16F10 melanoma cells, TNF-α reduced the melanogenesis and tyrosinase activity in a dose-dependent manner. These findings indicate that chronic stress induces fur color change by decreasing follicle melanocytes and tyrosinase activity in female C57BL/6 mice, and TNF-α may play an important role in stress-induced hair color change.
Animal Fur ; Animals ; Color ; Female ; Melanins ; Melanocytes ; enzymology ; Melanoma, Experimental ; Mice ; Mice, Inbred C57BL ; Monophenol Monooxygenase ; metabolism ; Pigmentation ; Skin ; physiopathology ; Stress, Physiological

PURPOSE: Barely sprout is a well-known oriental herbal medicine with a wide range of health benefits. Recent studies have provided scientific evidence of its therapeutic effects with expanded application. This study investigated anti-melanogenic effect of barley sprout water extract (BSE) in murine melanocyte B16F10. METHODS: Various concentrations (0, 50, 125, and 250 µg/mL) of BSE and arbutin (150 ppm) were applied to B16F10 stimulated with or without alpha-melanocyte stimulating hormone (100 nM) for 72 hours. The whitening potency of BSE was determined altered cellular melanin contents. Activity and expression of tyrosinase and microphthalmia-associated transcription factor (MITF) were also assayed. RESULTS: Experimental results revealed that treatment with BSE reduced cellular melanin production by approximately 40% compared to the control. Molecular findings supported that suppressed activity and expression of tyrosinase and MITF proteins by BSE were associated with declined cellular melanogenesis. Furthermore, anti-melanogenic effect of BSE (250 µg/mL) was similar to that of arbutin, a commonly used whitening agent. Lastly, polyphenols including p-coumaric, ferulic, and vanillic acids were identified in BSE using HPLC analyses. They might be potential active ingredients showing such melanogenesis-reducing effect. CONCLUSION: BSE was evident to possess favorable anti-melanogenic potency in an in vitro model. As a natural food sourced material, BSE could be an effective depigmentation agent with potential application in pharmaceutical and cosmetic industries.
Arbutin ; Chromatography, High Pressure Liquid ; Herbal Medicine ; Hordeum ; In Vitro Techniques ; Insurance Benefits ; Melanins ; Melanocytes ; Melanoma ; Microphthalmia-Associated Transcription Factor ; Monophenol Monooxygenase ; Polyphenols ; Therapeutic Uses ; Vanillic Acid ; Water

Melanogenesis is a biosynthetic pathway to produce melanin pigment in melanocyte, involving a series of intricate enzymatic and chemical catalyzed reactions. Melanogenesis involves five signaling pathways that converge on microphthalmia-associated transcription factor. In addition, many cytokines, involved in the regulation of melanogenesis, play an important role in the development, proliferation, differentiation and migration of melanocytes. Polyoxometalate can be used as a potential inhibitor of melanin production. Hence, this paper reviews the signaling pathways of melanogenesis and their regulatory mechanism, to apply polyoxometalates in the melanin production pathway, and briefly introduces the regulatory factors of related pathways.
Cell Differentiation ; Melanins ; Melanocytes ; Microphthalmia-Associated Transcription Factor ; Signal Transduction

Antigens, CD34 ; metabolism ; Biomarkers ; metabolism ; Cell Differentiation ; physiology ; Hair Follicle ; cytology ; Humans ; Intramolecular Oxidoreductases ; metabolism ; Keratinocytes ; metabolism ; Melanins ; metabolism ; Melanocytes ; metabolism ; PAX3 Transcription Factor ; metabolism ; Stem Cells ; metabolism

BACKGROUND: Although Eriobotrya japonica leaves have been studied as a raw material for various cosmetic products, little is known about the anti-oxidant, anti-inflammatory, and anti-melanogenic activities of Eriobotrya japonica leaf ethanol extract (EJEE). METHODS: This study was conducted to evaluate the anti-oxidant, anti-inflammatory, and anti-melanogenic activities of EJEE using different in vitro models. In addition, we investigated the potential irritation of EJEE to skin and eye using animal alternative tests. RESULTS: The total content of polyphenols, one of the active constituents of EJEE, was analyzed by high-performance liquid chromatography and found to contain 88.68 mg tannic acid equivalent/g. EJEE showed a concentration-dependent 1,1-diphenyl-2-picrylhydrazyl radical scavenging activity, 2,2′-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) radical scavenging activity, and a superoxide dismutase-like activity. The anti-inflammatory effect of 0.5% (w/v) EJEE was demonstrated by a reduction in lipopolysaccharide-induced nitric oxide and tumor necrosis factor-alpha levels in RAW 264.7 cells. EJEE also significantly inhibited melanogenesis in melanocyte stimulating hormone-induced B16F1 cells. EJEE did not show any irritation in skin and eye in animal alternative test. CONCLUSIONS: These results indicate that the EJEE possesses anti-oxidant, anti-inflammatory, and anti-melanogenic activities, while it did not induce toxicity or irritation in neither skin nor eye. Therefore, EJEE can be used as a cosmetic ingredient for skin improvement.
Animals ; Chromatography, Liquid ; Eriobotrya ; Ethanol ; In Vitro Techniques ; Melanocytes ; Nitric Oxide ; Polyphenols ; RAW 264.7 Cells ; Skin ; Superoxides ; Tannins ; Tumor Necrosis Factor-alpha

BACKGROUND: Vitiligo is a common acquired pigmentary disease caused by destruction of epidermal melanocytes in underlying autoimmune response. Few studies have been focused on the role of chemokines in non-segmental vitiligo (NSV) concomitant with autoimmune thyroid disease (AITD) and alopecia areata (AA). OBJECTIVE: The aim of this study was to determine the best serum biomarker for predictive role in the progression of vitiligo and to evaluate the influence of AA and/or AITD on vitiligo by using the biomarker. METHODS: This prospective cohort study recruited 45 NSV patients: 14 without either AITD or AA, 12 with AITD, 11 with AA, and 8 with both AITD and AA. Serum levels of CXCL1, CXCL8, CXCL9, CXCL10, CXCL12, CXCL13, and CXCL16 were analyzed by ELISA. CXCR3 mRNA expression was detected on PBMCs by RT-PCR. Improvement was evaluated using repigmentation scales. RESULTS: Serum CXCL10 levels, along with the expression of CXCR3 mRNA were higher in NSV patients with AITD or AA alone than in those without AITD or AA. Moreover, serum CXCL10 levels, along with the expression of CXCR3 mRNA were higher in NSV patients with both AITD and AA than in those with AITD or AA alone. Poorer repigmentation was observed in NSV patients with both AA and AITD than in those with AA or AITD alone. CONCLUSION: CXCL10 could be a biomarker to predict the progression of NSV. Dermatologists should pay much attention to those NSV patients concomitant with AITD and/or AA, for comorbidity might lead to more active autoimmune reaction.
Alopecia Areata ; Alopecia ; Autoimmunity ; Chemokine CXCL10 ; Chemokines ; Cohort Studies ; Comorbidity ; Enzyme-Linked Immunosorbent Assay ; Humans ; Melanocytes ; Prospective Studies ; RNA, Messenger ; Thyroid Diseases ; Thyroid Gland ; Vitiligo ; Weights and Measures