-
Stem Cell Research & Therapy Sep 2021Hyperpigmentation of skin is caused by an imbalance between the melanosome/melanin synthesis in melanocytes and the melanosome/melanin degradation in keratinocytes....
BACKGROUND
Hyperpigmentation of skin is caused by an imbalance between the melanosome/melanin synthesis in melanocytes and the melanosome/melanin degradation in keratinocytes. Although studies showed that stem cells play a role in hypopigmentation, the underlying mechanisms are far not elucidated. Human amniotic stem cells (hASCs) including human amniotic mesenchymal stem cells (hAMSCs) and human amniotic epithelial stem cells (hAESCs) were considered to be a promising cell source for stem cells-based therapy of many diseases clinically due to their pluripotent potential, no tumorigenesis and immunogenicity, no ethical issues, and potent paracrine effects. Here, we reported that both hASCs and their conditional medium (CM) had a potent anti-hyperpigmentation in skin in vivo and in vitro.
METHODS
hAESCs and hAMSCs were identified by RT-PCR, flow cytometric analysis and immunofluorescence. Effects of hASCs and hASC-CM on pigmentation were evaluated in B16F10 cells stimulated with α-melanocyte-stimulating hormone (α-MSH), and mouse ears or human skin substitutes treated with ultraviolet radiation B (UVB). Expressions of the key proteins related with melanogenesis and autophagic flux were detected by western blot in B16F10 cells for further exploring the effects and the underlying mechanisms of hAESC-CM and hAMSC-CM on melanogenesis and melanosome degradation. The hAMSCs exosomes-derived miRNAs were determined by sequencing. RT-PCR, western blot, melanin content analysis and luciferase activity assay were used to determine the hypopigmentation of miR-181a-5p and miR-199a.
RESULTS
In our study, we observed that both hASCs and their CM significantly alleviated the α-MSH in B16F10 cells or UVB-induced hyperpigmentation in mouse ears or human skin substitutes by suppressing melanin synthesis and promoting melanosome degradation in vivo and in vitro. Furthermore, we demonstrated that miR-181a-5p and miR-199a derived from hASCs exosomes remarkably inhibited melanogenesis by suppressing MITF (microphthalmia-associated transcription factor) which is a master regulator for governing melanogenesis and promoting melanosome degradation through activating autophagy, respectively.
CONCLUSIONS
Our studies provided strong evidence that the conditional medium and exosomes derived from hAMSCs inhibit skin hyperpigmentation by suppressing melanogenesis and promoting melanosome degradation, indicating that the hASCs exosomes or their released microRNAs might be as reagents for cell-free therapy in hyperpigmented disorders clinically.
Topics: Animals; Humans; Hyperpigmentation; Melanocytes; Melanosomes; Mice; MicroRNAs; Stem Cells; Ultraviolet Rays
PubMed: 34507619
DOI: 10.1186/s13287-021-02570-9 -
Traffic (Copenhagen, Denmark) Jun 2022In the skin epidermis, melanin is produced and stored within melanosomes in melanocytes, and then transferred to keratinocytes. Different models have been proposed to...
In the skin epidermis, melanin is produced and stored within melanosomes in melanocytes, and then transferred to keratinocytes. Different models have been proposed to explain the melanin transfer mechanism, which differ essentially in how melanin is transferred-either in a membrane-bound melanosome or as a melanosome core, that is, melanocore. Here, we investigated the endocytic route followed by melanocores and melanosomes during internalization by keratinocytes, by comparing the uptake of melanocores isolated from the supernatant of melanocyte cultures, with melanosomes isolated from melanocytes. We show that inhibition of actin dynamics impairs the uptake of both melanocores and melanosomes. Moreover, depletion of critical proteins involved in actin-dependent uptake mechanisms, namely Rac1, CtBP1/BARS, Cdc42 or RhoA, together with inhibition of Rac1-dependent signaling pathways or macropinocytosis suggest that melanocores are internalized by phagocytosis, whereas melanosomes are internalized by macropinocytosis. Interestingly, we found that Rac1, Cdc42 and RhoA are differently activated by melanocore or melanosome stimulation, supporting the existence of two distinct routes of melanin internalization. Furthermore, we show that melanocore uptake induces protease-activated receptor-2 (PAR-2) internalization by keratinocytes to a higher extent than melanosomes. Because skin pigmentation was shown to be regulated by PAR-2 activation, our results further support the melanocore-based mechanism of melanin transfer and further refine this model, which can now be described as coupled melanocore exo/phagocytosis.
Topics: Actins; Keratinocytes; Melanins; Melanocytes; Melanosomes; Phagocytosis; Receptor, PAR-2
PubMed: 35426185
DOI: 10.1111/tra.12843 -
JAMA Dermatology Jul 2015
Topics: Antibiotics, Antineoplastic; Female; Humans; Hypopigmentation; Male; Melanosomes; Sirolimus; Skin Neoplasms; Tuberous Sclerosis
PubMed: 25692853
DOI: 10.1001/jamadermatol.2014.4299 -
BioRxiv : the Preprint Server For... Jul 2023Pigment patterns are incredibly diverse across vertebrates and are shaped by multiple selective pressures from predator avoidance to mate choice. A common pattern across...
Pigment patterns are incredibly diverse across vertebrates and are shaped by multiple selective pressures from predator avoidance to mate choice. A common pattern across fishes, but for which we know little about the underlying mechanisms, is repeated melanic vertical bars. In order to understand genetic factors that modify the level or pattern of vertical barring, we generated a genetic cross of 322 F hybrids between two cichlid species with distinct barring patterns, and . We identify 48 significant quantitative trait loci that underlie a series of seven phenotypes related to the relative pigmentation intensity, and four traits related to patterning of the vertical bars. We find that genomic regions that generate variation in the level of eumelanin produced are largely independent of those that control the spacing of vertical bars. Candidate genes within these intervals include novel genes and those newly-associated with vertical bars, which could affect melanophore survival, fate decisions, pigment biosynthesis, and pigment distribution. Together, this work provides insights into the regulation of pigment diversity, with direct implications for an animal's fitness and the speciation process.
PubMed: 37461734
DOI: 10.1101/2023.07.02.547430 -
ACS Sensors Mar 2019Photoacoustic (optoacoustic) imaging can extract molecular information with deeper tissue penetration than possible by fluorescence microscopy techniques. However, there...
Photoacoustic (optoacoustic) imaging can extract molecular information with deeper tissue penetration than possible by fluorescence microscopy techniques. However, there is currently still a lack of robust genetically controlled contrast agents and molecular sensors that can dynamically detect biological analytes of interest with photoacoustics. In a biomimetic approach, we took inspiration from cuttlefish who can change their color by relocalizing pigment-filled organelles in so-called chromatophore cells under neurohumoral control. Analogously, we tested the use of melanophore cells from Xenopus laevis, containing compartments (melanosomes) filled with strongly absorbing melanin, as whole-cell sensors for optoacoustic imaging. Our results show that pigment relocalization in these cells, which is dependent on binding of a ligand of interest to a specific G protein-coupled receptor (GPCR), can be monitored in vitro and in vivo using photoacoustic mesoscopy. In addition to changes in the photoacoustic signal amplitudes, we could furthermore detect the melanosome aggregation process by a change in the frequency content of the photoacoustic signals. Using bioinspired engineering, we thus introduce a photoacoustic pigment relocalization sensor (PaPiReS) for molecular photoacoustic imaging of GPCR-mediated signaling molecules.
Topics: Animals; Cells, Cultured; Melanophores; Melatonin; Photoacoustic Techniques; Pigments, Biological; Xenopus laevis
PubMed: 30663315
DOI: 10.1021/acssensors.8b01319 -
Scientific Reports May 2021The coloring of zebrafish skin is often used as a model system to study biological pattern formation. However, the small number and lack of movement of chromatophores...
The coloring of zebrafish skin is often used as a model system to study biological pattern formation. However, the small number and lack of movement of chromatophores defies traditional Turing-type pattern generating mechanisms. Recent models invoke discrete short-range competition and long-range promotion between different pigment cells as an alternative to a reaction-diffusion scheme. In this work, we propose a lattice-based "Survival model," which is inspired by recent experimental findings on the nature of long-range chromatophore interactions. The Survival model produces stationary patterns with diffuse stripes and undergoes a Turing instability. We also examine the effect that domain growth, ubiquitous in biological systems, has on the patterns in both the Survival model and an earlier "Promotion" model. In both cases, domain growth alone is capable of orienting Turing patterns above a threshold wavelength and can reorient the stripes in ablated cells, though the wavelength for which the patterns orient is much larger for the Survival model. While the Survival model is a simplified representation of the multifaceted interactions between pigment cells, it reveals complex organizational behavior and may help to guide future studies.
Topics: Animals; Body Patterning; Cell Communication; Cell Proliferation; Cell Survival; Markov Chains; Melanophores; Models, Animal; Models, Biological; Monte Carlo Method; Skin Pigmentation; Zebrafish
PubMed: 33972585
DOI: 10.1038/s41598-021-89116-4 -
Scientific Reports Jan 2022Epigallocatechin gallate (EGCG) has the effect to protect skin from ultraviolet B (UVB) induced damages, but it is unstable under ambient conditions, being susceptible...
Epigallocatechin gallate (EGCG) has the effect to protect skin from ultraviolet B (UVB) induced damages, but it is unstable under ambient conditions, being susceptible to become brown in color. Gallocatechin gallate (GCG), an epimer counterpart of EGCG, is more stable chemically than EGCG. The potential effects of GCG against UVB-induced skin damages has not been available. The objective of this study was to investigate the protective effects of GCG against UVB-induced skin photodamages. GCG was topically applied on the skin of hairless mice at three dosage levels (LL, 12.5 mg/mL; ML 25 mg/mL; HL, 50 mg/mL), with EGCG and a commercially available baby sunscreen lotion SPF50 PA as control. The mice were then irradiated by UVB (fluence rate 1.7 µmol/m s) for 45 min. The treatments were carried out once a day for 6 consecutive days. Skin measurements and histological studies were performed at the end of experiment. The results show that GCG treatments at ML and HL levels inhibited the increase in levels of skin oil and pigmentation induced by UVB irradiation, and improved the skin elasticity and collagen fibers. GCG at ML and HL levels inhibited the formation of melanosomes and aberrations in mitochondria of UVB-irradiated skin in hairless mice. It is concluded that GCG protected skin from UVB-induced photodamages by improving skin elasticity and collagen fibers, and inhibiting aberrations in mitochondria and formation of melanosomes.
Topics: Administration, Cutaneous; Animals; Catechin; Female; Male; Melanosomes; Mice; Mice, Hairless; Mice, Inbred BALB C; Mitochondria; Petrolatum; Radiation Dosage; Skin; Sunscreening Agents; Ultraviolet Rays
PubMed: 35079059
DOI: 10.1038/s41598-022-05305-9 -
Proceedings of the National Academy of... Jun 2019Understanding genetic and cellular bases of adult form remains a fundamental goal at the intersection of developmental and evolutionary biology. The skin pigment cells...
Understanding genetic and cellular bases of adult form remains a fundamental goal at the intersection of developmental and evolutionary biology. The skin pigment cells of vertebrates, derived from embryonic neural crest, are a useful system for elucidating mechanisms of fate specification, pattern formation, and how particular phenotypes impact organismal behavior and ecology. In a survey of fishes, including the zebrafish , we identified two populations of white pigment cells-leucophores-one of which arises by transdifferentiation of adult melanophores and another of which develops from a yellow-orange xanthophore or xanthophore-like progenitor. Single-cell transcriptomic, mutational, chemical, and ultrastructural analyses of zebrafish leucophores revealed cell-type-specific chemical compositions, organelle configurations, and genetic requirements. At the organismal level, we identified distinct physiological responses of leucophores during environmental background matching, and we showed that leucophore complement influences behavior. Together, our studies reveal independently arisen pigment cell types and mechanisms of fate acquisition in zebrafish and illustrate how concerted analyses across hierarchical levels can provide insights into phenotypes and their evolution.
Topics: Animals; Cell Plasticity; Embryo, Nonmammalian; Gene Expression Regulation, Developmental; Genetics, Population; Melanophores; Mutation; Neural Crest; Phenotype; Pigmentation; Transcriptome; Zebrafish
PubMed: 31138706
DOI: 10.1073/pnas.1901021116 -
International Journal of Molecular... Aug 2021In this study, we used the zebrafish animal model to establish a bioassay by which physiological efficacy differential of alpha-melanocyte-stimulating hormone (α-MSH)...
In this study, we used the zebrafish animal model to establish a bioassay by which physiological efficacy differential of alpha-melanocyte-stimulating hormone (α-MSH) analogues could be measured by melanosome dispersion in zebrafish larvae. Brain-skin connection research has purported the interconnectedness between the nervous system and skin physiology. Accordingly, the neuropeptide α-MSH is a key regulator in several physiological processes, such as skin pigmentation in fish. In mammals, α-MSH has been found to regulate motivated behavior, appetite, and emotion, including stimulation of satiety and anxiety. Several clinical and animal model studies of autism spectrum disorder (ASD) have already demonstrated the effectiveness of α-MSH in restoring the social deficits of autism. Therefore, we sought to analyze the effect of synthetic and naturally-occurring α-MSH variants amongst different species. Our results showed that unique α-MSH derivatives from several fish species produced differential effects on the degree of melanophore dispersion. Using α-MSH human form as a standard, we could identify derivatives that induced greater physiological effects; particularly, the synthetic analogue melanotan-II (MT-II) exhibited a higher capacity for melanophore dispersion than human α-MSH. This was consistent with previous findings in an ASD mouse model demonstrating the effectiveness of MT-II in improving ASD behavioral symptoms. Thus, the melanophore assay may serve as a useful screening tool for therapeutic candidates for novel drug discovery.
Topics: Amino Acid Sequence; Animals; Biological Assay; Humans; Larva; Melanophores; Peptides, Cyclic; Sequence Homology; Skin Pigmentation; Zebrafish; alpha-MSH
PubMed: 34502223
DOI: 10.3390/ijms22179313 -
G3 (Bethesda, Md.) Sep 2022Hermansky-Pudlak syndrome is an autosomal recessive disease characterized by albinism, visual impairment, and blood platelet dysfunction. One of the genes responsible...
Hermansky-Pudlak syndrome is an autosomal recessive disease characterized by albinism, visual impairment, and blood platelet dysfunction. One of the genes responsible for Hermansky-Pudlak syndrome, hps1, regulates organelle biogenesis and thus plays important roles in melanin production, blood clotting, and the other organelle-related functions in humans and mice. However, the function of hps1 in other species remains poorly understood. In this study, we discovered albino medaka fish during the maintenance of a wild-derived population and identified hps1 as the responsible gene using positional cloning. In addition to the specific absence of melanophore pigmentation, the hps1 mutant showed reduced blood coagulation, suggesting that hps1 is involved in clotting caused by both mammalian platelets and fish thrombocytes. Together, the findings of our study demonstrate that hps1 has an evolutionarily conserved role in melanin production and blood coagulation. In addition, our study presents a useful vertebrate model for understanding the molecular mechanisms of Hermansky-Pudlak syndrome.
Topics: Albinism; Animals; Blood Coagulation; Hemorrhagic Disorders; Hermanski-Pudlak Syndrome; Humans; Mammals; Melanins; Membrane Proteins; Mice; Mutation; Oryzias
PubMed: 35944207
DOI: 10.1093/g3journal/jkac204