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*

Humans ; Hypopigmentation ; RNA, Long Noncoding/genetics* ; Vitiligo/genetics*

OBJECTIVE: To explore the genetic basis for a patient with clinically suspected neurofibromatosis type I, alopecia areata and vitiligo. METHODS: Variant of the NF1 gene was detected by chip capture and high-throughput sequencing. Candidate variant was verified by Sanger sequencing of the family trio. RESULTS: The patient was found to harbor a novel missense c.1885G>A (p.Gly629Arg) variant of the NF1 gene, for which neither parent was carrier. The variant was not recorded in the public database. Based on the guidelines for genetic variation of the American College of Medical Genetics and Genomics, the c.1885G>A missense variant was predicted to be pathogenic (PS1+PS2+PM2+PP3+PP4). CONCLUSION The c.1885G>A missense variant probably underlay the disease in this child. Above finding has enriched the spectrum of the NF1 gene variants.
Alopecia Areata/genetics* ; Child ; Genomics ; Humans ; Mutation ; Neurofibromatosis 1/genetics* ; Vitiligo/genetics*

Adaptor Proteins, Signal Transducing ; genetics ; Adult ; Asian Continental Ancestry Group ; China ; ethnology ; Female ; Genetic Predisposition to Disease ; Genotype ; Humans ; Male ; Polymorphism, Single Nucleotide ; Vitiligo ; genetics

Several chemical compounds can restore pigmentation in vitiligo through mechanisms that vary according to disease etiology. In the present study, we investigated the melanogenic activity of six structurally distinct compounds, namely, scopoletin, kaempferol, chrysin, vitamin D, piperine, and 6-benzylaminopurine. We determined their effectiveness, toxicity, and mechanism of action for stimulating pigmentation in B16F10 melanoma cells and in a zebrafish model. The melanogenic activity of 6-benzylaminopurine, the compound identified as the most potent, was further verified by measuring green fluorescent protein concentration in tyrp1 a: eGFP (tyrosinase-related protein 1) zebrafish and mitfa: eGFP (microphthalmia associated transcription factor) zebrafish and antioxidative activity. All the tested compounds were found to enhance melanogenesis responses both in vivo and in vitro at their respective optimal concentration by increasing melanin content and expression of TYR and MITF. 6-Benzyamino-purine showed the strongest re-pigmentation action at a concentration of 20 μmol·Lin vivo and 100 μmol·Lin vitro, and up-regulated the strong fluorescence expression of green fluorescent protein in tyrp1a: eGFP and mitfa: eGFP zebrafish in vitro. However, its relative anti-oxidative activity was found to be very low. Overall, our results indicated that 6-benzylaminopurine stimulated pigmentation through a direct mechanism, by increasing melanin content via positive regulation of tyrosinase activity in vitro, as well as up-regulating the expression of the green fluorescent protein in transgenic zebrafish in vivo.
Alkaloids ; chemistry ; pharmacology ; Animals ; Benzodioxoles ; chemistry ; pharmacology ; Benzyl Compounds ; chemistry ; pharmacology ; Cholecalciferol ; chemistry ; pharmacology ; Flavonoids ; chemistry ; pharmacology ; Humans ; Kaempferols ; chemistry ; pharmacology ; Melanins ; genetics ; metabolism ; Monophenol Monooxygenase ; genetics ; metabolism ; Pigmentation ; drug effects ; Piperidines ; chemistry ; pharmacology ; Polyunsaturated Alkamides ; chemistry ; pharmacology ; Purines ; chemistry ; pharmacology ; Scopoletin ; chemistry ; pharmacology ; Vitiligo ; drug therapy ; enzymology ; metabolism ; Zebrafish

Variation in human skin and hair color is the most notable aspect of human variability and several studies in evolution, genetics and developmental biology contributed to explain the mechanisms underlying human skin pigmentation, which is responsible for differences in skin color across the world's populations. Despite skin pigmentation is primarily related to melanocytes functionality, the surrounding keratinocytes and extracellular matrix proteins and fibroblasts in the underlying dermal compartment actively contribute to cutaneous homeostasis. Many autocrine/paracrine secreted factors and cell adhesion mechanisms involving both epidermal and dermal constituents determine constitutive skin pigmentation and, whenever deregulated, the occurrence of pigmentary disorders. In particular, an increased expression of such mediators and their specific receptors frequently lead to hyperpigmentary conditions, such as in melasma and in solar lentigo, whereas a defect in their expression/release is related to hypopigmented disorders, as seen in vitiligo. All these interactions underline the relevant role of pigmentation on human evolution and biology.
Biology ; Cell Adhesion ; Developmental Biology ; Extracellular Matrix Proteins ; Fibroblasts ; Genetics ; Hair Color ; Homeostasis ; Humans ; Intercellular Signaling Peptides and Proteins ; Keratinocytes ; Lentigo ; Melanocytes ; Melanosis ; Pigmentation ; Skin Pigmentation* ; Skin* ; Vitiligo

Genetic susceptibility is involved in the pathogenesis of vitiligo. Association studies with a whole genome-based approach instead of a single or a few candidate genes may be useful for discovering new susceptible genes. Although the etiology of non-segmental and segmental types is different, the association between gene polymorphisms and vitiligo has been reported, without defining types or in non-segmental type. Whole genome-based single nucleotide polymorphisms (SNPs) were examined in patients with non-segmental and segmental types of vitiligo using the Affymetrix GeneChip 500K mapping array, and 10 functional classes of significant SNPs were selected. Genotyping and data analysis of selected 10 SNPs was performed using real-time PCR. Genotype and allele frequencies were significantly different between both types of vitiligo and three of the target SNPs, DNAH5 (rs2277046), STRN3 (rs2273171), and KIAA1005 (rs3213758). A stronger association was suggested between the mutation in KIAA1005 (rs3213758) and the segmental type compared to the non-segmental type of vitiligo. DNAH5 (rs2277046), STRN3 (rs2273171), and KIAA1005 (rs3213758) may be new vitiligo-related SNPs in Korean patients, either non-segmental or segmental type.
Adaptor Proteins, Signal Transducing/*genetics ; Adolescent ; Adult ; Aged ; Aged, 80 and over ; Asian Continental Ancestry Group/*genetics ; Autoantigens/*genetics ; Axonemal Dyneins/*genetics ; Calmodulin-Binding Proteins/*genetics ; Child ; Child, Preschool ; Female ; Gene Frequency ; *Genome, Human ; Genome-Wide Association Study ; Genotype ; Humans ; Male ; Middle Aged ; Polymorphism, Single Nucleotide ; Republic of Korea ; Vitiligo/*genetics ; Young Adult

To compare the difference in tumor immunity and autoimmunity elicited by adenovirus (Ad) encoding human or murine tyrosinase-related protein 2 (AdhTRP2 or AdmTRP2), and to find the most effective way to induce immunity by AdhTRP2 or AdmTRP2, C57BL/6 mice were immunized with AdhTRP2 or AdmTRP2 intramuscularly at different doses of 10(5), 10(6), 10(7) and 10(8) separately (10 mice for each dose). Two weeks after the immunization, in vivo CTL assay and intracellular staining (ICS) of IFN-gamma were carried out to analyze the dose-effect relationship. Tumor growth and vitiligo (as an sign of autoimmunity) were observed until 3 months after challenge with 10(5) B16F10 tumor cells. The results showed that Ad encoding AdmTrp2 induced weak tumor immune response. Similar immunization with AdhTrp-2 elicited stronger protective immunity. CTL activity and IFN-gamma-produced CD8+T cells were directly proportional to dose of AdhTrp2 or AdmTrp2. Moreover, AdhTrp2 group showed tumor rejection in 100% of challenged mice till the end of 3rd month while 60% of mice immunized with AdmTrp2 were protected against tumor. In the whole process of this experiment, no vitiligo was observed in mice immunized either with AdhTrp2 or AdmTrp2. It is concluded that anti-melanoma responses induced by genetic vaccination expressing xenoantigens breaks immune tolerance effectively and is able to elicit strong antigen-specific cytotoxic T cell response without vitiligo.
Adenoviridae/metabolism ; Antineoplastic Agents/*pharmacology ; Cell Line, Tumor ; Cytokines/metabolism ; Immune System ; Immune Tolerance ; Interferon-gamma/metabolism ; Intramolecular Oxidoreductases/*biosynthesis ; Intramolecular Oxidoreductases/*genetics ; Mice, Inbred C57BL ; T-Lymphocytes, Cytotoxic/*metabolism ; Vitiligo/*metabolism

OBJECTIVETo investigate the association of HLA class I and II alleles with generalized vitiligo in ethnic Han Chinese in north China.

METHODSBy employing polymerase chain reaction sequence-specific primer (PCR-SSP) procedure 34 generalized vitiligo patients in north China were studied for HLA I and II alleles and were compared with 102 healthy controls.

RESULTSThe allelic frequencies of HLA-A*30, Cw*06, DRB1*07, and DQB1*0201 were increased significantly in generalized vitiligo and especially in the patients without family history compared with the controls.

CONCLUSIONThese alleles positively associated with generalized vitiligo in Chinese Han patients in north China, might provide clues to reveal the susceptibility gene(s) of vitiligo in Chinese and as well as the immunnogenetic mechanisms of disease.

Adult ; Aged ; Aged, 80 and over ; Alleles ; Asian Continental Ancestry Group ; genetics ; China ; Female ; Gene Frequency ; Genes, MHC Class I ; genetics ; Genes, MHC Class II ; genetics ; Genotype ; Humans ; Male ; Middle Aged ; Vitiligo ; ethnology ; genetics

OBJECTIVEGenetic factors are thought to be involved in the development of vitiligo. The aim of this study is to explore the possible genetic model of vitiligo by analyzing the genetic characteristics of 815 patients from Zhejiang province.

METHODSData for 815 patients with vitiligo together with their first- and second-degree relatives were obtained using a standardized questionnaire. All these information was requested to confirm the answers about family history in order to reduce the possibility of 'recall' bias. The 815 probands would include 411 (50.43%) males and 404 (49.57%) females with a varied age from 2 months to 71 years old. Since the information on general prevalence of vitiligo in this area was absent, a control group was set up to facilitate the calculations of heritability degree. 468 persons of the control group were from non-vitiligo population with a sex ratio of 241(male): 227(female) with varied age of 4 months to 80 years old. Both gender and age were comparable between the vitiligo and the control population. The inheritance pattern estimation, heritability calculation and complex segregation analysis were performed with Penrose method, Falconer regression method and SAGE-REGTL program.

RESULTSIn 815 vitiligo probands, 128 had and 687 had not family histories, with a heritability rate of 15.7%. The vitiligo prevalence in proband's first degree relatives was 2.580%, higher than the prevalence of 0.618% in second degree relatives, and both of them were higher than general prevalence: 0.192%. By Penrose method, the rates on different catagories were as follows: sibling prevalence rates s = 0.080 18; population prevalence rate q = 0.001 92; s/q = 41.76. The ratio of s/q did not approach 1/2q (260.42) or 1/4q (130.21), but approached 1/square root of q(22.82), suggesting vitiligo was consistent with a mode of polygenic inheritance. Using Falconer's method, heritabilities of vitiligo in first-and second degree relatives of probands were 59.61% (95% confidence interval 65.37-53.84) and 55.20% (95% confidence interval 43.88-66.52), respectively. The weighted average of heritability in all relatives was 58.7% (95% confidence interval 53.56-63.83). The results of complex segregation analysis suggested that major gene model including the Mendelian dominant, recessive and additive hypotheses were not rejected (P > 0.05). Purely environmental model and no transmission model were rejected at a 0. 001 significance level. According to AIC, Mendelian dominant inheritance was the best-fitted hypothesis.

CONCLUSIONGenetic factors played an important role in the occurrence of vitiligo, and the genetic model of vitiligo could serve as the polygenetic or multifactorial inheritance with major gene trait.

Adolescent ; Adult ; Aged ; Aged, 80 and over ; Child ; Child, Preschool ; China ; epidemiology ; Female ; Humans ; Infant ; Male ; Middle Aged ; Models, Genetic ; Vitiligo ; epidemiology ; genetics ; Young Adult