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Genome Biology Oct 2021Zebrafish pigment cell differentiation provides an attractive model for studying cell fate progression as a neural crest progenitor engenders diverse cell types,...
BACKGROUND
Zebrafish pigment cell differentiation provides an attractive model for studying cell fate progression as a neural crest progenitor engenders diverse cell types, including two morphologically distinct pigment cells: black melanophores and reflective iridophores. Nontrivial classical genetic and transcriptomic approaches have revealed essential molecular mechanisms and gene regulatory circuits that drive neural crest-derived cell fate decisions. However, how the epigenetic landscape contributes to pigment cell differentiation, especially in the context of iridophore cell fate, is poorly understood.
RESULTS
We chart the global changes in the epigenetic landscape, including DNA methylation and chromatin accessibility, during neural crest differentiation into melanophores and iridophores to identify epigenetic determinants shaping cell type-specific gene expression. Motif enrichment in the epigenetically dynamic regions reveals putative transcription factors that might be responsible for driving pigment cell identity. Through this effort, in the relatively uncharacterized iridophores, we validate alx4a as a necessary and sufficient transcription factor for iridophore differentiation and present evidence on alx4a's potential regulatory role in guanine synthesis pathway.
CONCLUSIONS
Pigment cell fate is marked by substantial DNA demethylation events coupled with dynamic chromatin accessibility to potentiate gene regulation through cis-regulatory control. Here, we provide a multi-omic resource for neural crest differentiation into melanophores and iridophores. This work led to the discovery and validation of iridophore-specific alx4a transcription factor.
Topics: Animals; Cell Differentiation; Chromatin; Chromatophores; CpG Islands; DNA Methylation; Epigenesis, Genetic; Gene Regulatory Networks; Melanophores; Neural Crest; Regulatory Sequences, Nucleic Acid; Transcription Factors; Transcription, Genetic; Zebrafish; Zebrafish Proteins
PubMed: 34607603
DOI: 10.1186/s13059-021-02493-x -
The Journal of Investigative Dermatology Feb 2020Skin depigmentation diseases, such as vitiligo, are pigmentation disorders that often destroy melanocytes. However, their pathological mechanisms remain unclear, and...
Skin depigmentation diseases, such as vitiligo, are pigmentation disorders that often destroy melanocytes. However, their pathological mechanisms remain unclear, and therefore, promising treatments or prevention has been lacking. Here, we demonstrate that a zebrafish insertional mutant showing a significant reduction of nicastrin transcript possesses melanosome maturation defect, Tyrosinase-dependent mitochondrial swelling, and melanophore cell death. The depigmentation phenotypes are proven to be a result of γ-secretase inactivation. Furthermore, live imaging demonstrates that macrophages are recruited to and can phagocytose melanophore debris. Thus, we characterize a potential zebrafish depigmentation disease model, a nicastrin mutant, which can be used for further treatment or drug development of diseases related to skin depigmentation and/or inflammation.
Topics: Amyloid Precursor Protein Secretases; Animals; Animals, Genetically Modified; Disease Models, Animal; Embryo, Nonmammalian; Humans; Hypopigmentation; Melanosomes; Membrane Glycoproteins; Microscopy, Electron, Transmission; Monophenol Monooxygenase; Mutation; Skin; Skin Pigmentation; Zebrafish; Zebrafish Proteins
PubMed: 31437444
DOI: 10.1016/j.jid.2019.07.702 -
International Journal of Molecular... Nov 2022cAMP-PKA signaling plays a pivotal role in melanin synthesis and melanosome transport by responding to the binding of the α-melanocyte-stimulating hormone (α-MSH) to...
cAMP-PKA signaling plays a pivotal role in melanin synthesis and melanosome transport by responding to the binding of the α-melanocyte-stimulating hormone (α-MSH) to melanocortin-1 receptor (MC1R). Adenylate cyclases (ADCYs) are the enzymes responsible for the synthesis of cAMP from ATP, which comprises nine transmembrane isoforms (ADCYs 1-9) and one soluble adenylate cyclase (ADCY 10) in mammals. However, little is known about which and how ADCY isoforms regulate melanocyte generation, melanin biosynthesis, and melanosome transport in vivo. In this study, we have generated a series of single and double mutants of Adcy isoforms in zebrafish. Among them, and double mutants cause defects in melanosome dispersion but do not impair melanoblast differentiation and melanocyte regeneration during the embryonic or larval stages. Activation of PKA, the main effector of cAMP signaling, significantly ameliorates the defects in melanosome dispersion in and double mutants. Mechanistically, Adcy3a and Adcy5 regulate melanosome dispersion by activating kinesin-1 while inhibiting cytoplasmic dynein-1. In adult zebrafish, Adcy3a and Adcy5 participate in the regulation of the expression of microphthalmia transcription factor (Mitfa) and melanin synthesis enzymes Tyr, Dct, and Trp1b. The deletion of Adcy3a and Adcy5 inhibits melanin production and reduces pigmented melanocyte numbers, causing a defect in establishing adult melanocyte stripes. Hence, our studies demonstrate that Adcy3a and Adcy5 play essential but redundant functions in mediating α-MSH-MC1R/cAMP-PKA signaling for regulating melanin synthesis and melanosome dispersion.
Topics: Animals; Melanosomes; Zebrafish; Melanins; alpha-MSH; Melanocytes; Receptor, Melanocortin, Type 1; Mammals
PubMed: 36430661
DOI: 10.3390/ijms232214182 -
Current Opinion in Genetics &... Aug 2017Recent studies demonstrated that neural crest-derived Schwann cell precursors (SCPs) dwelling in the nerves are multipotent and can be recruited in the local tissue to... (Review)
Review
Recent studies demonstrated that neural crest-derived Schwann cell precursors (SCPs) dwelling in the nerves are multipotent and can be recruited in the local tissue to provide building blocks of neural crest-derived nature. The variety of fates produced by SCPs is widening with every year and currently includes melanocytes/melanophores, parasympathetic and enteric neurons, endoneural fibroblast, mesenchymal stem cells and, of course, mature Schwann cells of different subtypes. However, it is still unclear if SCPs are, in fact, nerve-dwelling population of the neural crest or they are rather a different, more specialized, cell type. This review outlines the field and focuses on the capacity of nerve-associated glial progenitors to contribute to the development and regeneration of numerous tissues in various groups of vertebrates.
Topics: Animals; Biological Evolution; Cell Differentiation; Neural Crest; Neuroglia; Neuronal Plasticity; Neurons; Peripheral Nerves; Schwann Cells; Stem Cells
PubMed: 28242477
DOI: 10.1016/j.gde.2017.02.006 -
Pigment Cell & Melanoma Research Jul 2022The skin acts as a barrier to environmental insults and provides many vital functions. One of these is to shield DNA from harmful ultraviolet radiation, which is...
The skin acts as a barrier to environmental insults and provides many vital functions. One of these is to shield DNA from harmful ultraviolet radiation, which is achieved by skin pigmentation arising as melanin is produced and dispersed within the epidermal layer. This is a crucial defence against DNA damage, photo-ageing and skin cancer. The mechanisms and regulation of melanogenesis and melanin transfer involve extensive crosstalk between melanocytes and keratinocytes in the epidermis, as well as fibroblasts in the dermal layer. Although the predominant mechanism of melanin transfer continues to be debated and several plausible models have been proposed, we and others previously provided evidence for a coupled exo/phagocytosis model. Herein, we performed histology and immunohistochemistry analyses and demonstrated that a newly developed full-thickness three-dimensional reconstructed human pigmented skin model and an epidermis-only model exhibit dispersed pigment throughout keratinocytes in the epidermis. Transmission electron microscopy revealed melanocores between melanocytes and keratinocytes, suggesting that melanin is transferred through coupled exocytosis/phagocytosis of the melanosome core, or melanocore, similar to our previous observations in human skin biopsies. We, therefore, present evidence that our in vitro models of pigmented human skin show epidermal pigmentation comparable to human skin. These findings have a high value for studies of skin pigmentation mechanisms and pigmentary disorders, whilst reducing the reliance on animal models and human skin biopsies.
Topics: Animals; Epidermis; Humans; Keratinocytes; Melanins; Melanocytes; Melanosomes; Pigmentation; Skin; Skin Pigmentation; Ultraviolet Rays
PubMed: 35325505
DOI: 10.1111/pcmr.13039 -
Anatomical Record (Hoboken, N.J. : 2007) Dec 2022The heart begins to form early during vertebrate development and is the first functional organ of the embryo. This study aimed to describe and compare the heart...
The heart begins to form early during vertebrate development and is the first functional organ of the embryo. This study aimed to describe and compare the heart development in three Neotropical anuran species, Physalaemus albonotatus, Elachistocleis bicolor, and Scinax nasicus. Different Gosner Stages (GS) of embryos (GS 18-20) and premetamorphic (GS 21-25), prometamorphic (GS 26-41), and metamorphic (GS 42-46) tadpoles were analyzed using stereoscopic microscopy and Scanning Electronic Microscopy. Heart development was similar in the three analyzed species; however, some heterochronic events were identified between P. albonotatus and S. nasicus compared to E. bicolor. In addition, different patterns of melanophores arrangement were observed. During the embryonic and metamorphic periods, the main morphogenetic events occur: formation of the heart tube, regionalization of the heart compartments, development of spiral valve, onset of heartbeat, looping, and final displacement of the atrium and its complete septation. Both periods are critical for the normal morphogenesis and the correct functioning of the anuran heart. These results are useful to characterize the normal anuran heart morphology and to identify possible abnormalities caused by exposure to environmental contaminants.
Topics: Animals; Organogenesis; Anura; Larva; Morphogenesis; Heart
PubMed: 35412699
DOI: 10.1002/ar.24933 -
Cells Mar 2021Zebrafish has emerged as a powerful model in studies dealing with pigment development and pathobiology of pigment diseases. Due to its conserved pigment pattern with...
Zebrafish has emerged as a powerful model in studies dealing with pigment development and pathobiology of pigment diseases. Due to its conserved pigment pattern with established genetic background, the zebrafish is used for screening of active compounds influencing melanophore, iridophore, and xanthophore development and differentiation. In our study, zebrafish embryos and larvae were used to investigate the influence of third-generation noncompetitive P-glycoprotein inhibitor, tariquidar (TQR), on pigmentation, including phenotype effects and changes in gene expression of chosen chromatophore differentiation markers. Five-day exposure to increasing TQR concentrations (1 µM, 10 µM, and 50 µM) resulted in a dose-dependent augmentation of the area covered with melanophores but a reduction in the area covered by iridophores. The observations were performed in three distinct regions-the eye, dorsal head, and tail. Moreover, TQR enhanced melanophore renewal after depigmentation caused by 0.2 mM 1-phenyl-2-thiourea (PTU) treatment. qPCR analysis performed in 56-h post-fertilization (hpf) embryos demonstrated differential expression patterns of genes related to pigment development and differentiation. The most substantial findings include those indicating that TQR had no significant influence on leukocyte tyrosine kinase, GTP cyclohydrolase 2, tyrosinase-related protein 1, and forkhead box D3, however, markedly upregulated tyrosinase, dopachrome tautomerase and melanocyte inducing transcription factor, and downregulated purine nucleoside phosphorylase 4a. The present study suggests that TQR is an agent with multidirectional properties toward pigment cell formation and distribution in the zebrafish larvae and therefore points to the involvement of P-glycoprotein in this process.
Topics: ATP Binding Cassette Transporter, Subfamily B, Member 1; Animals; Cell Differentiation; Gene Expression Profiling; Gene Expression Regulation; Gene Expression Regulation, Developmental; Larva; Melanins; Melanophores; Pigmentation; Quinolines; RNA, Messenger; Zebrafish; Zebrafish Proteins
PubMed: 33804686
DOI: 10.3390/cells10030690 -
International Journal of Molecular... Oct 2023Red coloration is considered an economically important trait in some fish species, including spotted scat, a marine aquaculture fish. Erythrophores are gradually covered...
Red coloration is considered an economically important trait in some fish species, including spotted scat, a marine aquaculture fish. Erythrophores are gradually covered by melanophores from the embryonic stage. Despite studies of black spot formation and melanophore coloration in the species, little is known about erythrophore development, which is responsible for red coloration. 1-phenyl 2-thiourea (PTU) is a tyrosinase inhibitor commonly used to inhibit melanogenesis and contribute to the visualization of embryonic development. In this study, spotted scat embryos were treated with 0.003% PTU from 0 to 72 h post fertilization (hpf) to inhibit melanin. Erythrophores were clearly observed during the embryonic stage from 14 to 72 hpf, showing an initial increase (14 to 36 hpf), followed by a gradual decrease (36 to 72 hpf). The number and size of erythrophores at 36 hpf were larger than those at 24 and 72 hpf. At 36 hpf, LC-MS and absorbance spectrophotometry revealed that the carotenoid content was eight times higher than the pteridine content, and β-carotene and lutein were the main pigments related to red coloration in spotted scat larvae. Compared with their expression in the normal hatching group, , , and related to retinol metabolism and and related to steroid hormone biosynthesis and steroid biosynthesis were significantly up-regulated in the PTU group, and associated with phototransduction was significantly down-regulated. By qRT-PCR, the expression levels of genes involved in carotenoid metabolism (, , , , , and ), pteridine synthesis (), and chromatophore differentiation ( and ) were significantly higher at 36 hpf than at 24 hpf and 72 hpf, except for . These gene expression profiles were consistent with the developmental changes of erythrophores. These findings provide insights into pigment cell differentiation and gene function in the regulation of red coloration and contribute to selective breeding programs for ornamental aquatic animals.
Topics: Animals; Larva; Fishes; Gene Expression Profiling; Carotenoids; Pteridines; Steroids
PubMed: 37895036
DOI: 10.3390/ijms242015356 -
Scientific Reports May 2022Lower vertebrates, including fish, can rapidly alter skin lightness through changes in melanin concentration and melanosomes' mobility according to various factors,...
Lower vertebrates, including fish, can rapidly alter skin lightness through changes in melanin concentration and melanosomes' mobility according to various factors, which include background color, light intensity, ambient temperature, social context, husbandry practices and acute or chronic stressful stimuli. Within this framework, the determination of skin chromaticity parameters in fish species is estimated either in specific areas using colorimeters or at the whole animal level using image processing and analysis software. Nevertheless, the accurate quantification of melanin content or melanophore coverage in fish skin is quite challenging as a result of the laborious chemical analysis and the typical application of simple optical imaging methods, requiring also to euthanize the fish in order to obtain large skin samples for relevant investigations. Here we present the application of a novel hybrid confocal fluorescence and photoacoustic microscopy prototype for the label-free imaging and quantification of melanin in fish scales samples with high spatial resolution, sensitivity and detection specificity. The hybrid images are automatically processed through optimized algorithms, aiming at the accurate and rapid extraction of various melanin accumulation indices in large datasets (i.e., total melanin content, melanophores' area, density and coverage) corresponding to different fish species and groups. Furthermore, convolutional neural network-based algorithms have been trained using the recorded data towards the classification of different scales' samples with high accuracy. In this context, we demonstrate that the proposed methodology may increase substantially the precision, as well as, simplify and expedite the relevant procedures for the quantification of melanin content in marine organisms.
Topics: Animals; Melanins; Melanophores; Microscopy; Skin Pigmentation; Spectrum Analysis
PubMed: 35504968
DOI: 10.1038/s41598-022-11262-0 -
Scientific Reports Jan 2022Yellow mutant rainbow trout (YR), an economically important aquaculture species, is popular among consumers due to its excellent meat quality and attractive appearance.... (Comparative Study)
Comparative Study
Yellow mutant rainbow trout (YR), an economically important aquaculture species, is popular among consumers due to its excellent meat quality and attractive appearance. Skin color is a key economic trait for YR, but little is known about the molecular mechanism of skin color development. In this study, YR skin transcriptomes were analyzed to explore temporal expression patterns of pigmentation-related genes in three different stages of skin color development. In total, 16,590, 16,682, and 5619 genes were differentially expressed between fish at 1 day post-hatching (YR1d) and YR45d, YR1d and YR90d, and YR45d and YR90d. Numerous differentially expressed genes (DEGs) associated with pigmentation were identified, and almost all of them involved in pteridine and carotenoid synthesis were significantly upregulated in YR45d and YR90d compared to YR1d, including GCH1, PTS, QDPR, CSFIR1, SLC2A11, SCARB1, DGAT2, PNPLA2, APOD, and BCO2. Interestingly, many DEGs enriched in melanin synthesis pathways were also significantly upregulated, including melanogenesis (MITF, MC1R, SLC45A2, OCA2, and GPR143), tyrosine metabolism (TYR, TYRP1, and DCT), and MAPK signaling (KITA) pathways. Using short time-series expression miner, we identified eight differential gene expression pattern profiles, and DEGs in profile 7 were associated with skin pigmentation. Protein-protein interaction network analysis showed that two modules were related to xanthophores and melanophores. In addition, 1,812,329 simple sequence repeats and 2,011,334 single-nucleotide polymorphisms were discovered. The results enhance our understanding of the molecular mechanism underlying skin pigmentation in YR, and could accelerate the molecular breeding of fish species with valuable skin color traits and will likely be highly informative for developing new therapeutic approaches to treat pigmentation disorders and melanoma.
Topics: Animals; Fish Proteins; Gene Expression Profiling; Gene Expression Regulation, Developmental; Gene Regulatory Networks; Genotype; Mutation; Oncorhynchus mykiss; Phenotype; Polymorphism, Single Nucleotide; Protein Interaction Maps; RNA-Seq; Signal Transduction; Skin Pigmentation; Transcriptome
PubMed: 34997156
DOI: 10.1038/s41598-021-04255-y