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1.
Anticancer Res ; 39(5): 2447-2451, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-31092438

RESUMO

BACKGROUND/AIM: The insulin-like growth factor 1 (IGF1) signaling pathway as an aging mechanism related to p53 in human melanogenesis remains unclear. The aim of this study was to investigate the relationship between p53 and IGF1 signaling pathway in young, senescent and H2O2-treated cells. MATERIALS AND METHODS: The protein and gene expression in young, senescent and H2O2-treated cells were analyzed using western blot and reverse transcription polymerase chain reaction (RT-PCR) assays, respectively. RESULTS: The expression levels of (phosphoinositide 3-kinases) PI3K, v-akt murine thymoma viral oncogene homolog 1 (AKT1), mammalian target of rapamycin, ß-catenin (CTNNB1), acetylated p53 (ac-p53), p53 and p-p21 proteins, related to IGF1 and p53 signaling pathways, were higher in senescent and H2O2-treated cells than those of young cells. Furthermore, AKT reduced melanogenesis through microphthalmia-associated transcription factor (MITF) inactivation by the inhibition of CTNNB1. The gene expression levels of PI3K, TP53 and catalase (CAT) in senescent and H2O2-treated cells were increased compared to young cells. CONCLUSION: p53 protein plays a key role in the aging of melanocytes via IGF1 signaling pathways.


Assuntos
Envelhecimento/genética , Proliferação de Células/genética , Fator de Crescimento Insulin-Like I/genética , Proteína Supressora de Tumor p53/genética , Envelhecimento/metabolismo , Envelhecimento/patologia , Animais , Catalase/genética , Proliferação de Células/efeitos dos fármacos , Senescência Celular/genética , Regulação da Expressão Gênica/efeitos dos fármacos , Humanos , Peróxido de Hidrogênio/toxicidade , Melanócitos/metabolismo , Melanócitos/patologia , Camundongos , Fator de Transcrição Associado à Microftalmia/genética , Fosfatidilinositol 3-Quinases/genética , Proteínas Proto-Oncogênicas c-akt/genética , Transdução de Sinais/efeitos dos fármacos , beta Catenina/antagonistas & inibidores , beta Catenina/genética
2.
Int J Mol Sci ; 20(9)2019 May 02.
Artigo em Inglês | MEDLINE | ID: mdl-31052497

RESUMO

The purpose of the present study is to evaluate the effect of rice bran ash mineral extract (RBM) on pigmentation in zebrafish (Danio rerio). Melanin has the ability to block ultraviolet (UV) radiation and scavenge free oxygen radicals, thus protecting the skin from their harmful effects. Agents that increase melanin synthesis in melanocytes may reduce the risk of photodamage and skin cancer. The present study investigates the effect of RBM on pigmentation in zebrafish and the underlying mechanism. RBM was found to significantly increase the expression of microphthalmia-associated transcription factor (MITF), a key transcription factor involved in melanin production. RBM also suppressed the phosphorylation of extracellular signal-regulated kinase (ERK), which negatively regulates zebrafish pigmentation. Together, these results suggest that RBM promotes melanin biosynthesis in zebrafish.


Assuntos
Oryza/química , Pigmentação/efeitos dos fármacos , Extratos Vegetais/química , Extratos Vegetais/farmacologia , Peixe-Zebra/fisiologia , Animais , Sistema de Sinalização das MAP Quinases/efeitos dos fármacos , Melaninas/metabolismo , Fator de Transcrição Associado à Microftalmia/genética , Fator de Transcrição Associado à Microftalmia/metabolismo , Fosforilação/efeitos dos fármacos , Regulação para Cima/efeitos dos fármacos , Peixe-Zebra/genética , Proteínas de Peixe-Zebra/genética , Proteínas de Peixe-Zebra/metabolismo
3.
Genes Dev ; 33(15-16): 983-1007, 2019 08 01.
Artigo em Inglês | MEDLINE | ID: mdl-31123060

RESUMO

All transcription factors are equal, but some are more equal than others. In the 25 yr since the gene encoding the microphthalmia-associated transcription factor (MITF) was first isolated, MITF has emerged as a key coordinator of many aspects of melanocyte and melanoma biology. Like all transcription factors, MITF binds to specific DNA sequences and up-regulates or down-regulates its target genes. What marks MITF as being remarkable among its peers is the sheer range of biological processes that it appears to coordinate. These include cell survival, differentiation, proliferation, invasion, senescence, metabolism, and DNA damage repair. In this article we present our current understanding of MITF's role and regulation in development and disease, as well as those of the MITF-related factors TFEB and TFE3, and highlight key areas where our knowledge of MITF regulation and function is limited.


Assuntos
Fatores de Transcrição de Zíper de Leucina e Hélice-Alça-Hélix Básicos/metabolismo , Regulação Neoplásica da Expressão Gênica , Melanócitos/fisiologia , Melanoma/fisiopatologia , Fator de Transcrição Associado à Microftalmia/metabolismo , Animais , Genoma , Humanos , Fator de Transcrição Associado à Microftalmia/genética , Ligação Proteica , Isoformas de Proteínas
4.
Gene ; 704: 86-90, 2019 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-30978479

RESUMO

The purpose of this study is to profile the clinical and genetic features of Japanese Waardenburg syndrome (WS) patients and validate the W index. Sixteen Japanese WS families with congenital sensorineural hearing loss were included in the study. The inner canthal, interpupillary, and outer canthal distances (ICD, IPD, and OCD) were measured for all patients, and patients were screened for presence of PAX3, MITF, SOX10, and EDNRB mutations. The WS patients were clinically classified under the current W index as follows: 13 families with WS1, 2 families with WS2, and 1 family with WS4. In the 13 WS1 families, genetic tests found PAX3 mutations in 5 families, MITF mutations in 4 families, SOX10 mutations in 3 families, and EDNRB mutations in 1 family. 61% of clinically classified WS1 patients under the current W index conflicted with the genetic classification, which implies W index is not appropriate for Japanese population. Resetting the threshold of W index or novel index formulated with ethnicity matched samples is necessary for clinical classification which is consistent with genetic classification for WS patients with distinct ethnicity.


Assuntos
Grupo com Ancestrais do Continente Asiático/genética , Síndrome de Waardenburg/diagnóstico , Síndrome de Waardenburg/genética , Adulto , Criança , Códon sem Sentido , Análise Mutacional de DNA , Família , Feminino , Mutação da Fase de Leitura , Frequência do Gene , Estudos de Associação Genética , Predisposição Genética para Doença , Testes Genéticos , Humanos , Japão , Masculino , Fator de Transcrição Associado à Microftalmia/genética , Fator de Transcrição PAX3/genética , Linhagem , Receptor de Endotelina B/genética , Fatores de Transcrição SOXE/genética , Síndrome de Waardenburg/etnologia
5.
Biomed Res Int ; 2019: 5971546, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31008108

RESUMO

It has long been believed that histamine is associated with cutaneous melanogenesis. Specifically, H2-receptor antagonists reportedly inhibit melanogenesis, but H1-receptor antagonists, which are some of the most commonly prescribed medicines in dermatology, have not been studied to determine whether and how they regulate melanogenesis. Therefore, we screened H1-receptor antagonists to determine whether they inhibit melanogenesis and found that loratadine was particularly effective, in this regard without compromising cellular viability. Loratadine downregulated microphthalmia-associated transcription factor (MITF) and tyrosinase in melanocytes. To determine the intracellular signaling pathways, Akt was consistently activated by loratadine. PI3K/Akt pathway inhibitor, LY294002, restored the reduced melanin content that was induced by loratadine. In addition, phospho-GSK-3ß also was found to be increased following loratadine treatment. Loratadine reduced the amount of PKC-ßII in the membrane fraction, thereby decreasing its activity. Taken together, our data indicate that loratadine regulates melanogenesis via Akt/MITF and PKC-ßII signaling, thereby leading to the inhibition of melanogenic proteins. The antimelanogenic effects of loratadine have potentially significant and useful roles in dermatologic practice, although further clinical studies will be required to test this.


Assuntos
Antagonistas dos Receptores Histamínicos H1/farmacologia , Loratadina/farmacologia , Melaninas/biossíntese , Receptores Histamínicos H1/genética , Linhagem Celular , Sobrevivência Celular/efeitos dos fármacos , Cromonas/farmacologia , Regulação da Expressão Gênica/efeitos dos fármacos , Humanos , Melaninas/genética , Melanócitos/efeitos dos fármacos , Melanócitos/metabolismo , Fator de Transcrição Associado à Microftalmia/genética , Morfolinas/farmacologia , Fosfatidilinositol 3-Quinases/metabolismo , Proteína Quinase C beta/genética , Proteína Quinase C beta/metabolismo , Proteínas Proto-Oncogênicas c-akt/metabolismo , Transdução de Sinais/efeitos dos fármacos
6.
Int J Mol Sci ; 20(5)2019 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-30823658

RESUMO

Melanoma is a skin tumor with a high tendency for metastasis and thus is one of the deadliest cancers worldwide. Here, we investigated the expression of the scavenger receptor class B type 1 (SR-BI), a high-density lipoprotein (HDL) receptor, and tested for its role in melanoma pigmentation as well as extracellular vesicle release. We first analyzed the expression of SR-BI in patient samples and found a strong correlation with MITF expression as well as with the melanin synthesis pathway. Hence, we asked whether SR-BI could also play a role for the secretory pathway in metastatic melanoma cells. Interestingly, gain- and loss-of-function of SR-BI revealed regulation of the proto-oncogene MET. In line, SR-BI knockdown reduced expression of the small GTPase RABB22A, the ESCRT-II protein VPS25, and SNAP25, a member of the SNARE complex. Accordingly, reduced overall extracellular vesicle generation was detected upon loss of SR-BI. In summary, SR-BI expression in human melanoma enhances the formation and transport of extracellular vesicles, thereby contributing to the metastatic phenotype. Therapeutic targeting of SR-BI would not only interfere with cholesterol uptake, but also with the secretory pathway, therefore suppressing a key hallmark of the metastatic program.


Assuntos
Vesículas Extracelulares/metabolismo , Melanoma/metabolismo , Fator de Transcrição Associado à Microftalmia/genética , Receptores Depuradores Classe B/genética , Linhagem Celular Tumoral , Regulação para Baixo , Regulação Neoplásica da Expressão Gênica , Humanos , Melanoma/genética , Fator de Transcrição Associado à Microftalmia/metabolismo , Receptores Depuradores Classe B/metabolismo , Proteína 25 Associada a Sinaptossoma/genética , Proteína 25 Associada a Sinaptossoma/metabolismo , Proteínas de Transporte Vesicular/genética , Proteínas de Transporte Vesicular/metabolismo , Proteínas rab de Ligação ao GTP/genética , Proteínas rab de Ligação ao GTP/metabolismo
7.
eNeuro ; 6(1)2019 Jan-Feb.
Artigo em Inglês | MEDLINE | ID: mdl-30895220

RESUMO

Seizures are characterized by hypersynchronization of neuronal networks. Understanding these networks could provide a critical window for therapeutic control of recurrent seizure activity, i.e., epilepsy. However, imaging seizure networks has largely been limited to microcircuits in vitro or small "windows" in vivo. Here, we combine fast confocal imaging of genetically encoded calcium indicator (GCaMP)-expressing larval zebrafish with local field potential (LFP) recordings to study epileptiform events at whole-brain and single-neuron levels in vivo. Using an acute seizure model (pentylenetetrazole, PTZ), we reliably observed recurrent electrographic ictal-like events associated with generalized activation of all major brain regions and uncovered a well-preserved anterior-to-posterior seizure propagation pattern. We also examined brain-wide network synchronization and spatiotemporal patterns of neuronal activity in the optic tectum microcircuit. Brain-wide and single-neuronal level analysis of PTZ-exposed and 4-aminopyridine (4-AP)-exposed zebrafish revealed distinct network dynamics associated with seizure and non-seizure hyperexcitable states, respectively. Neuronal ensembles, comprised of coactive neurons, were also uncovered during interictal-like periods. Taken together, these results demonstrate that macro- and micro-network calcium motifs in zebrafish may provide a greater understanding of epilepsy.


Assuntos
Encéfalo/fisiopatologia , Cálcio/metabolismo , Convulsões/fisiopatologia , Animais , Animais Geneticamente Modificados , Encéfalo/patologia , Sincronização Cortical , Epilepsia/metabolismo , Epilepsia/fisiopatologia , Fator de Transcrição Associado à Microftalmia/genética , Fator de Transcrição Associado à Microftalmia/metabolismo , Vias Neurais/patologia , Vias Neurais/fisiopatologia , Pentilenotetrazol , Convulsões/patologia , Peixe-Zebra , Proteínas de Peixe-Zebra/genética , Proteínas de Peixe-Zebra/metabolismo
8.
Biochim Biophys Acta Gene Regul Mech ; 1862(4): 472-485, 2019 04.
Artigo em Inglês | MEDLINE | ID: mdl-30840854

RESUMO

The multidomain RNase III endoribonuclease DICER is required for the generation of most functional microRNAs (miRNAs). Loss of Dicer affects developmental processes at different levels. Here, we characterized the zebrafish Dicer1 mutant, dicer1sa9205, which has a single point mutation induced by N-ethyl-N-nitrosourea mutagenesis. Heterozygous dicer1sa9205 developed normally, being phenotypically indistinguishable from wild-type siblings. Homozygous dicer1sa9205 mutants display smaller eyes, abnormal craniofacial development and aberrant pigmentation. Reduced numbers of both iridophores and melanocytes were observed in the head and ventral trunk of dicer1sa9205 homozygotes; the effect on melanocytes was stronger and detectable earlier in development. The expression of microphthalmia-associated transcription factor a (mitfa), the master gene for melanocytes differentiation, was enhanced in dicer1-depleted fish. Similarly, the expression of SRY-box containing gene 10 (sox10), required for mitfa activation, was higher in mutants than in wild types. In silico and in vivo analyses of either sox10 or mitfa 3'UTRs revealed conserved potential miRNA binding sites likely involved in the post-transcriptional regulation of both genes. Based on these findings, we propose that dicer1 participates in the gene regulatory network governing zebrafish melanocyte differentiation by controlling the expression of mitfa and sox10.


Assuntos
Cartilagem/anormalidades , Melanócitos/citologia , Ribonuclease III/fisiologia , Proteínas de Peixe-Zebra/fisiologia , Regiões 3' não Traduzidas , Animais , Apoptose , Cartilagem/crescimento & desenvolvimento , Embrião não Mamífero/anormalidades , Embrião não Mamífero/anatomia & histologia , Regulação da Expressão Gênica , Cabeça , Larva/anatomia & histologia , Melanócitos/metabolismo , Fator de Transcrição Associado à Microftalmia/genética , Fator de Transcrição Associado à Microftalmia/metabolismo , Monofenol Mono-Oxigenase/metabolismo , Mutação , Crista Neural/citologia , Ribonuclease III/genética , Fatores de Transcrição SOXE/genética , Fatores de Transcrição SOXE/metabolismo , Peixe-Zebra/embriologia , Peixe-Zebra/genética , Peixe-Zebra/crescimento & desenvolvimento , Peixe-Zebra/metabolismo , Proteínas de Peixe-Zebra/genética , Proteínas de Peixe-Zebra/metabolismo
9.
Proc Natl Acad Sci U S A ; 116(12): 5687-5692, 2019 03 19.
Artigo em Inglês | MEDLINE | ID: mdl-30842276

RESUMO

Melanoma differentiation-associated gene-7/interleukin-24 (mda-7/IL-24) is a multifunctional cytokine displaying broad-spectrum anticancer activity in vitro or in vivo in preclinical animal cancer models and in a phase 1/2 clinical trial in patients with advanced cancers. mda-7/IL-24 targets specific miRNAs, including miR-221 and miR-320, for down-regulation in a cancer-selective manner. We demonstrate that mda-7/IL-24, administered through a replication incompetent type 5 adenovirus (Ad.mda-7) or with His-MDA-7/IL-24 protein, down-regulates DICER, a critical regulator in miRNA processing. This effect is specific for mature miR-221, as it does not affect Pri-miR-221 expression, and the DICER protein, as no changes occur in other miRNA processing cofactors, including DROSHA, PASHA, or Argonaute. DICER is unchanged by Ad.mda-7/IL-24 in normal immortal prostate cells, whereas Ad.mda-7 down-regulates DICER in multiple cancer cells including glioblastoma multiforme and prostate, breast, lung, and liver carcinoma cells. MDA-7/IL-24 protein down-regulates DICER expression through canonical IL-20/IL-22 receptors. Gain- and loss-of-function studies confirm that overexpression of DICER rescues deregulation of miRNAs by mda-7/IL-24, partially rescuing cancer cells from mda-7/IL-24-mediated cell death. Stable overexpression of DICER in cancer cells impedes Ad.mda-7 or His-MDA-7/IL-24 inhibition of cell growth, colony formation, PARP cleavage, and apoptosis. In addition, stable overexpression of DICER renders cancer cells more resistant to Ad.mda-7 inhibition of primary and secondary tumor growth. MDA-7/IL-24-mediated regulation of DICER is reactive oxygen species-dependent and mediated by melanogenesis-associated transcription factor. Our research uncovers a distinct role of mda-7/IL-24 in the regulation of miRNA biogenesis through alteration of the MITF-DICER pathway.


Assuntos
RNA Helicases DEAD-box/metabolismo , Interleucinas/metabolismo , MicroRNAs/metabolismo , Fator de Transcrição Associado à Microftalmia/metabolismo , Ribonuclease III/metabolismo , Animais , Apoptose/fisiologia , Diferenciação Celular/fisiologia , Linhagem Celular Tumoral , Proliferação de Células/fisiologia , RNA Helicases DEAD-box/biossíntese , RNA Helicases DEAD-box/genética , Regulação para Baixo , Genes Supressores de Tumor , Humanos , Interleucinas/genética , Masculino , Camundongos , Camundongos Nus , MicroRNAs/biossíntese , Fator de Transcrição Associado à Microftalmia/genética , Neoplasias/genética , Neoplasias/metabolismo , Neoplasias/patologia , Neoplasias da Próstata/genética , Neoplasias da Próstata/metabolismo , Neoplasias da Próstata/parasitologia , Espécies Reativas de Oxigênio/metabolismo , Ribonuclease III/biossíntese , Ribonuclease III/genética , Transdução de Sinais , Ensaios Antitumorais Modelo de Xenoenxerto/métodos
10.
Anim Genet ; 50(2): 143-149, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-30730042

RESUMO

The llama (Lama glama) is a fiber-producing species that presents a wide range of coat colors, among which white is one of the most important for the textile industry. However, there is little information about the molecular mechanisms that control the white phenotype in this species. In domestic mammals, a white coat is usually produced by mutations in the KIT proto-oncogene receptor tyrosine kinase (KIT) and microphthalmia-associated transcription factor (MITF) genes. In this work we have sequenced and described the coding regions of KIT and MITF-M, the melanocyte-specific isoform, and the two transcriptional variants MITF-M(-) and MITF-M(+). Moreover, we studied the expression of these genes in the skin of white and colored llamas. Although no variants were revealed to be associated with white coat color, significant differences between phenotypes were observed in the expression levels of KIT and MITF-M. Interestingly, white llamas expressed less MITF-M(+) than did colored ones, which is consistent with a consequent reduction in the synthesis of melanin. Even though our results indicate that downregulation of KIT and MITF-M expression is involved in white phenotype production in llamas, the causative gene of white coat color remains unknown.


Assuntos
Camelídeos Americanos/genética , Regulação da Expressão Gênica , Variação Genética , Fator de Transcrição Associado à Microftalmia/genética , Fases de Leitura Aberta/genética , Proteínas Proto-Oncogênicas c-kit/genética , Animais , Camelídeos Americanos/fisiologia , Cabelo/química , Cor de Cabelo/genética , Fator de Transcrição Associado à Microftalmia/metabolismo , Proteínas Proto-Oncogênicas c-kit/metabolismo , Análise de Sequência de DNA/veterinária
11.
Mol Biol Rep ; 46(2): 2461-2471, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-30805890

RESUMO

The purpose of this study is to investigate the effect of H2O2 on the aging of melanogenesis in human melanocytes. The staining of SA-ß-galactosidase, an aging marker, was remarkably increased in the cells aged with H2O2 at 62.5 µM or more compared with young cells. The intracellular H2O2 level and melanin synthesis were also reduced in both H2O2-treated cells and senescent cells compared with young cells in DCFH-DA assay. Both the senescent cells and the H2O2-treated cells showed higher expression level of Catalase than young cells in western blot and immunofluorescence staining. Furthermore, the expression levels of TRP-1, TRP-2 and p300 were reduced in both senescent cells and the H2O2-treated cells, but that of SIRT-1 was inverted compared with young cells. In addition, H2O2 reduced the expression level of MITF but increased that of Nrf2 in nucleus. Those results indicate that the expression levels of antioxidant enzymes in senescent cells and H2O2-treated cell are upregulated, but the expression levels of proteins involved in melanin synthesis are downregulated. Above findings suggest that H2O2 could play a key role in the aging process of melanogenesis through modulation of MITF and Nrf2.


Assuntos
Envelhecimento/efeitos dos fármacos , Peróxido de Hidrogênio/metabolismo , Melanócitos/efeitos dos fármacos , Linhagem Celular , Senescência Celular , Humanos , Peróxido de Hidrogênio/efeitos adversos , Melaninas/biossíntese , Melaninas/metabolismo , Fator de Transcrição Associado à Microftalmia/genética , Fator de Transcrição Associado à Microftalmia/metabolismo , Fator 2 Relacionado a NF-E2/genética , Fator 2 Relacionado a NF-E2/metabolismo , Oxirredutases , Transdução de Sinais/efeitos dos fármacos , beta-Galactosidase/efeitos dos fármacos
12.
Oncogene ; 38(19): 3616-3635, 2019 05.
Artigo em Inglês | MEDLINE | ID: mdl-30651597

RESUMO

The melanocytic lineage, which is prominently exposed to ultraviolet radiation (UVR) and radiation-independent oxidative damage, requires specific DNA-damage response mechanisms to maintain genomic and transcriptional homeostasis. The coordinate lineage-specific regulation of intricately intertwined DNA repair and transcription is incompletely understood. Here we demonstrate that the Microphthalmia-associated transcription factor (MITF) directly controls general transcription and UVR-induced nucleotide excision repair by transactivation of GTF2H1 as a core element of TFIIH. Thus, MITF ensures the rapid resumption of transcription after completion of strand repair and maintains transcriptional output, which is indispensable for survival of the melanocytic lineage including melanoma in vitro and in vivo. Moreover, MITF controls c-MYC implicated in general transcription by transactivation of far upstream binding protein 2 (FUBP2/KSHRP), which induces c-MYC pulse regulation through TFIIH, and experimental depletion of MITF results in consecutive loss of CDK7 in the TFIIH-CAK subcomplex. Targeted for proteasomal degradation, CDK7 is dependent on transactivation by MITF or c-MYC to maintain a steady state. The dependence of TFIIH-CAK on sequence-specific MITF and c-MYC constitutes a previously unrecognized mechanism feeding into super-enhancer-driven or other oncogenic transcriptional circuitries, which supports the concept of a transcription-directed therapeutic intervention in melanoma.


Assuntos
Reparo do DNA/fisiologia , Fator de Transcrição Associado à Microftalmia/metabolismo , Fosfoproteínas/metabolismo , Fator de Transcrição TFIIH/metabolismo , Fatores de Transcrição TFII/metabolismo , Animais , Células Cultivadas , Reparo do DNA/efeitos da radiação , Receptor com Domínio Discoidina 1/genética , Receptor com Domínio Discoidina 1/metabolismo , Feminino , Genes myc , Humanos , Melanócitos/fisiologia , Melanócitos/efeitos da radiação , Melanoma/metabolismo , Melanoma/patologia , Camundongos SCID , Fator de Transcrição Associado à Microftalmia/genética , Fosfoproteínas/genética , Neoplasias Cutâneas/metabolismo , Neoplasias Cutâneas/patologia , Fator de Transcrição TFIIH/genética , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo , Fatores de Transcrição TFII/genética , Transcrição Genética , Raios Ultravioleta
13.
Chem Biol Interact ; 300: 1-7, 2019 Feb 25.
Artigo em Inglês | MEDLINE | ID: mdl-30597128

RESUMO

Research into materials that inhibit melanogenesis in skin has gained interest. Screening for such compounds in B16F10 cells revealed that cyclohexyl-[2-(3,5-dimethyl-pyrazol-1-yl)-6-methyl-pyrimidin-4-yl]-amine (CyPPA), a positive modulator of small-conductance Ca2+-activated K+ channels, is a strong inhibitor of melanogenesis. We investigated the anti-melanogenic activity of CyPPA and the molecular mechanism by which CyPPA reduced melanin production in normal human melanocytes (NHM). CyPPA treatment resulted in a significant concentration-dependent reduction in melanin content without significant cytotoxicity; treatment likewise resulted in a significant time-dependent reduction in tyrosinase (TYR) activity. Treatment with CyPPA also decreased transcription of melanogenesis-related genes, including the gene encoding microphthalmia-associated transcription factor (MITF). In addition, visual evaluation of the MelanoDerm™ human skin model revealed significantly lower melanin content in the CyPPA-treated condition than in the untreated control. CyPPA was determined to modulate glycogen synthase kinase-3ß (GSK3ß) activity, thereby leading to a decrease in ß-catenin/MITF expression. Thus, CyPPA acts as a melanogenesis inhibitor by modulating the GSK3ß/ß-catenin/MITF pathway.


Assuntos
Glicogênio Sintase Quinase 3 beta/metabolismo , Pirazóis/farmacologia , Pirimidinas/farmacologia , Transdução de Sinais/efeitos dos fármacos , beta Catenina/metabolismo , Animais , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Regulação para Baixo/efeitos dos fármacos , Humanos , Melaninas/metabolismo , Melanócitos/citologia , Melanócitos/efeitos dos fármacos , Melanócitos/metabolismo , Melanoma Experimental/metabolismo , Melanoma Experimental/patologia , Camundongos , Camundongos Endogâmicos C57BL , Fator de Transcrição Associado à Microftalmia/genética , Fator de Transcrição Associado à Microftalmia/metabolismo , Pirazóis/química , Pirimidinas/química , Interferência de RNA , RNA Interferente Pequeno/metabolismo , Canais de Potássio Ativados por Cálcio de Condutância Baixa/antagonistas & inibidores , Canais de Potássio Ativados por Cálcio de Condutância Baixa/genética , Canais de Potássio Ativados por Cálcio de Condutância Baixa/metabolismo
14.
Neural Dev ; 14(1): 1, 2019 01 11.
Artigo em Inglês | MEDLINE | ID: mdl-30635004

RESUMO

BACKGROUND: Waardenburg syndrome (WS) is the consequence of an inherited autosomal dominant mutation which causes the early degeneration of intermediate cells of cochlear stria vascularis (SV) and profound hearing loss. Patients with WS may also experience primary vestibular symptoms. Most of the current WS studies did not discuss the relationship between WS and abnormal vestibular function. Our study found that a spontaneous mutant pig showed profound hearing loss and depigmentation. MITF-M, a common gene mutation causes type WS which affect the development of the intermediate cell of SV, was then identified for animal modeling. RESULTS: In this study, the degeneration of vestibular hair cells was found in pigs with MITF-M. The morphology of hair cells in vestibular organs of pigs was examined using electron microscopy from embryonic day E70 to postnatal two weeks. Significant hair cell loss in the mutant saccule was found in this study through E95 to P14. Conversely, there was no hair cell loss in either utricle or semi-circular canals. CONCLUSIONS: Our study suggested that MITF-M gene mutation only affects hair cells of the saccule, but has no effect on other vestibular organs. The study also indicated that the survival of cochlear and saccular hair cells was dependent on the potassium release from the cochlear SV, but hair cells of the utricle and semi-circular canals were independent on SV.


Assuntos
Doenças Cocleares/genética , Células Ciliadas Vestibulares/patologia , Perda Auditiva/genética , Fator de Transcrição Associado à Microftalmia/genética , Transtornos da Pigmentação/genética , Sáculo e Utrículo/patologia , Síndrome de Waardenburg/genética , Animais , Doenças Cocleares/patologia , Doenças Cocleares/fisiopatologia , Modelos Animais de Doenças , Perda Auditiva/fisiopatologia , Sáculo e Utrículo/diagnóstico por imagem , Suínos , Potenciais Evocados Miogênicos Vestibulares/fisiologia , Síndrome de Waardenburg/patologia , Síndrome de Waardenburg/fisiopatologia
15.
Anim Genet ; 50(2): 172-174, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-30644113

RESUMO

White spotting phenotypes in horses are highly valued in some breeds. They are quite variable and may range from the common white markings up to completely white horses. EDNRB, KIT, MITF, PAX3 and TRPM1 represent known candidate genes for white spotting phenotypes in horses. For the present study, we investigated an American Paint Horse family segregating a phenotype involving white spotting and blue eyes. Six of eight horses with the white-spotting phenotype were deaf. We obtained whole-genome sequence data from an affected horse and specifically searched for structural variants in the known candidate genes. This analysis revealed a heterozygous ~63-kb deletion spanning exons 6-9 of the MITF gene (chr16:21 503 211-21 566 617). We confirmed the breakpoints of the deletion by PCR and Sanger sequencing. PCR-based genotyping revealed that all eight available affected horses from the family carried the deletion. The finding of an MITF variant fits well with the syndromic phenotype involving both depigmentation and an increased risk for deafness and corresponds to human Waardenburg syndrome type 2A. Our findings will enable more precise genetic testing for depigmentation phenotypes in horses.


Assuntos
Surdez/veterinária , Deleção de Genes , Doenças dos Cavalos/genética , Cavalos/genética , Fator de Transcrição Associado à Microftalmia/genética , Animais , Cor , Surdez/genética , Feminino , Masculino , Fator de Transcrição Associado à Microftalmia/metabolismo , Pigmentação/genética , Fatores de Risco , Sequenciamento Completo do Genoma/veterinária
16.
Br Poult Sci ; 60(2): 105-108, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-30595026

RESUMO

1. The c/c alleles are responsible for the white plumage colour of ducks; however, the gene corresponding to this locus is still unclear. In order to identify the locus-related candidate gene associated with duck's plumage colour pattern, it was necessary to analyse the whole genome resequencing data. 2. A total of 929,465 SNPs in chromosome 13 and 1,688 SNPs in the region of the Microphthalmia-Associated Transcription Factor (MITF) gene were identified from whole genome resequencing data analysis. After construction of an FST plot from chromosome 13, MITF was highlighted as a candidate gene, possessing the highest FST value (0.811) on chromosome 13. 3. Six novel SNPs were discovered, located in the intronic region of the MITF gene. F2 progeny of Kaiya × Liancheng ducks (N = 1,061) were selected for genotyping by the Restriction Fragment Length Polymorphism (RFLP) technique. Association analysis using Haploview software was used for validation of the results. 4. Association results between SNPs and phenotypes showed significant association with corresponding phenotypes. All the significantly associated SNPs were located in the identified candidate gene. 5. The identified candidate gene provided novel information which is important in marker-assisted selection and breeding of duck and for the investigation of the C locus recessive white genetic mechanisms underlying plumage colour pattern.


Assuntos
Proteínas Aviárias/genética , Patos/fisiologia , Plumas/fisiologia , Genes Recessivos , Fator de Transcrição Associado à Microftalmia/genética , Pigmentação/genética , Animais , Proteínas Aviárias/metabolismo , China , Cor , Patos/genética , Fator de Transcrição Associado à Microftalmia/metabolismo , Sequenciamento Completo do Genoma/veterinária
18.
Gene ; 688: 155-162, 2019 Mar 10.
Artigo em Inglês | MEDLINE | ID: mdl-30552980

RESUMO

The microphthalmia-associated transcription factor (MITF) is the center of the regulator network of melanin synthesis in vertebrates. However, the role of MITF in shell color formation is poorly studied in mollusks. In the present study, an MITF gene, PyMITF, was first identified at the whole-genome level in Yesso scallop (Patinopecten yessoensis), an evolutionarily and economically important species, the shell color of which shows polymorphism. The PyMITF is a large gene spanning ~37 kb in the genome with 7 introns and 8 exons. A basic helix-loop-helix leucine zipper (bHLH-LZ) domain was detected in the PyMITF protein sequence, which can bind the canonical E-box sequence in the promoter region of the downstream genes. Phylogenetic analysis of the MITFs among vertebrates and invertebrates revealed that the molecular evolution of MITFs was consistent with the species taxonomy. Different expression levels of PyMITF were detected among different shell color strains, indicating the important role of PyMITF involved in shell pigmentation. Besides, PyMITF was expressed at a significantly higher level in the central mantle than that in the edge mantle, proving the participation of the central mantle in shell color formation in molecular level for the first time. The work provides valuable information for the molecular mechanism study of shell color formation.


Assuntos
Exoesqueleto/fisiologia , Genoma/genética , Pectinidae/genética , Pigmentação/genética , Animais , Cor , Estudo de Associação Genômica Ampla/métodos , Fator de Transcrição Associado à Microftalmia/genética , Filogenia
19.
J Immunother Cancer ; 6(1): 159, 2018 12 27.
Artigo em Inglês | MEDLINE | ID: mdl-30591082

RESUMO

BACKGROUND: Microphthalmia Transcription Factor (MITF)family translocation renal cell carcinoma (tRCC) is a rare RCC subtype harboring TFE3/TFEB translocations. The prognosis in the metastatic (m) setting is poor. Programmed death ligand-1 expression was reported in 90% of cases, prompting us to analyze the benefit of immune checkpoint inhibitors (ICI) in this population. PATIENTS AND METHODS: This multicenter retrospective study identified patients with MITF family mtRCC who had received an ICI in any of 12 referral centers in France or the USA. Response rate according to RECIST criteria, progression-free survival (PFS), and overall survival (OS) were analyzed. Genomic alterations associated with response were determined for 8 patients. RESULTS: Overall, 24 patients with metastatic disease who received an ICI as second or later line of treatment were identified. Nineteen (82.6%) of these patients had received a VEGFR inhibitor as first-line treatment, with a median PFS of 3 months (range, 1-22 months). The median PFS for patients during first ICI treatment was 2.5 months (range, 1-40 months); 4 patients experienced partial response (16,7%) and 3 (12,5%) had stable disease. Of the patients whose genomic alterations were analyzed, two patients with mutations in bromodomain-containing genes (PBRM1 and BRD8) had a clinical benefit. Resistant clones in a patient with exceptional response to ipilimumab showed loss of BRD8 mutations and increased mutational load driven by parallel evolution affecting 17 genes (median mutations per gene, 3), which were enriched mainly for O-glycan processing (29.4%, FDR = 9.7 × 10- 6). CONCLUSIONS: MITF family tRCC is an aggressive disease with similar responses to ICIs as clear-cell RCC. Mutations in bromodomain-containing genes might be associated with clinical benefit. The unexpected observation about parallel evolution of genes involved in O-glycosylation as a mechanism of resistance to ICI warrants exploration.


Assuntos
Antineoplásicos Imunológicos/uso terapêutico , Carcinoma de Células Renais/genética , Imunomodulação/efeitos dos fármacos , Neoplasias Renais/genética , Fator de Transcrição Associado à Microftalmia/genética , Família Multigênica , Translocação Genética , Adolescente , Adulto , Idoso , Antineoplásicos Imunológicos/farmacologia , Biomarcadores Tumorais , Carcinoma de Células Renais/tratamento farmacológico , Carcinoma de Células Renais/mortalidade , Carcinoma de Células Renais/patologia , Criança , Pré-Escolar , Feminino , Genômica/métodos , Humanos , Estimativa de Kaplan-Meier , Neoplasias Renais/tratamento farmacológico , Neoplasias Renais/mortalidade , Neoplasias Renais/patologia , Masculino , Fator de Transcrição Associado à Microftalmia/antagonistas & inibidores , Pessoa de Meia-Idade , Estadiamento de Neoplasias , Inibidores de Proteínas Quinases/farmacologia , Inibidores de Proteínas Quinases/uso terapêutico , Receptores de Fatores de Crescimento do Endotélio Vascular/antagonistas & inibidores , Estudos Retrospectivos , Resultado do Tratamento , Adulto Jovem
20.
Invest Ophthalmol Vis Sci ; 59(15): 6067-6073, 2018 12 03.
Artigo em Inglês | MEDLINE | ID: mdl-30590377

RESUMO

Purpose: Complete deficiency of microphthalmia transcription factor (MITF) in Mitfmi-vga9/mi-vga9 mice is associated with microphthalmia, retinal dysplasia, and albinism. We investigated the ability of dopachrome tautomerase (DCT) promoter-mediated inducible ectopic expression of Mitf-M to rescue these phenotypic abnormalities. Methods: A new mouse line was created with doxycycline-inducible ectopic Mitf-M expression on an Mitf-deficient Mitfmi-vga9 background (DMV mouse). Adult DMV mice were phenotypically characterized and tissues were collected for histology, immunohistochemistry, and evaluation of Mitf, pigmentary genes, and retinal pigment epithelium (RPE) gene expression. Results: Ectopic Mitf-M expression was specifically induced in the eyes, but was not detected in the skin of DMV mice. Inducible expression of Mitf-M partially rescued the microphthalmia, RPE structure, and pigmentation as well as a subset of the choroidal and iris melanocytes but not cutaneous melanocytes. RPE function and vision were not restored in the DMV mice. Conclusions: Ectopic expression of Mitf-M during development of Mitf-deficient mice is capable of partially rescuing ocular and retinal structures and uveal melanocytes. These findings provide novel information about the roles of Mitf isoforms in the development of mouse eyes.


Assuntos
Expressão Ectópica do Gene/fisiologia , Regulação da Expressão Gênica no Desenvolvimento/fisiologia , Fator de Transcrição Associado à Microftalmia/genética , Epitélio Pigmentado da Retina/metabolismo , Animais , Western Blotting , Corioide/citologia , Desenvolvimento Embrionário , Feminino , Perfilação da Expressão Gênica , Técnicas de Genotipagem , Imuno-Histoquímica , Oxirredutases Intramoleculares/farmacologia , Iris/citologia , Masculino , Melanócitos/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Microftalmia/metabolismo , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Pele/citologia
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