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Kaufmann M, Han Z. RPE melanin and its influence on the progression of AMD. Ageing Res Rev 2024; 99:102358. [PMID: 38830546 PMCID: PMC11260545 DOI: 10.1016/j.arr.2024.102358] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2024] [Accepted: 05/27/2024] [Indexed: 06/05/2024]
Abstract
OBJECTIVE The aim of this review article is to summarize the latest findings and current understanding of the origin of melanin in the retinal pigment epithelium (RPE), its function within the RPE, its role in the pathogenesis of age-related macular degeneration (AMD), its effect on retinal development, and its potential therapeutic benefit in the treatment of AMD. METHODS A comprehensive search of peer-reviewed journals was conducted using various combinations of key terms such as "melanin," "retinal pigment epithelium" or "RPE," "age-related macular degeneration" or AMD," "lipofuscin," "oxidative stress," and "albinism." Databases searched include PubMed, Scopus, Science Direct, and Google Scholar. 147 papers published between the years of 1957 and 2023 were considered with an emphasis on recent findings. SUMMARY OF FINDINGS AMD is thought to result from chronic oxidative stress within the RPE that results in cellular dysfunction, metabolic dysregulation, inflammation, and lipofuscin accumulation. Melanin functions as a photoscreener, free radical scavenger, and metal cation binding reservoir within the RPE. RPE melanin does not regenerate, and it undergoes degradation over time in response to chronic light exposure and oxidative stress. RPE melanin is important for retinal development and RPE function, and in the aging eye, melanin loss is associated with increased lipid peroxidation, inflammation, and the accumulation of toxic oxidized cellular products. Therefore, melanin-based treatments may serve to preserve RPE and retinal function in AMD. CONCLUSIONS The pathogenesis of AMD is not fully understood, but RPE dysfunction and melanin loss in response to chronic oxidative stress and inflammation are thought to be primary drivers of the disease. Due to melanin's antioxidative effects, melanin-based nanotechnology represents a promising avenue for the treatment of AMD.
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Affiliation(s)
- Mary Kaufmann
- University of North Carolina School of Medicine, Chapel Hill, NC 27599, USA
| | - Zongchao Han
- Department of Ophthalmology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA; Division of Pharmacoengineering & Molecular Pharmaceutics, Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA.
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2
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Snyman M, Walsdorf RE, Wix SN, Gill JG. The metabolism of melanin synthesis-From melanocytes to melanoma. Pigment Cell Melanoma Res 2024; 37:438-452. [PMID: 38445351 PMCID: PMC11178461 DOI: 10.1111/pcmr.13165] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2023] [Revised: 02/06/2024] [Accepted: 02/18/2024] [Indexed: 03/07/2024]
Abstract
Melanin synthesis involves the successful coordination of metabolic pathways across multiple intracellular compartments including the melanosome, mitochondria, ER/Golgi, and cytoplasm. While pigment production offers a communal protection from UV damage, the process also requires anabolic and redox demands that must be carefully managed by melanocytes. In this report we provide an updated review on melanin metabolism, including recent data leveraging new techniques, and technologies in the field of metabolism. We also discuss the many aspects of melanin synthesis that intersect with metabolic pathways known to impact melanoma phenotypes and behavior. By reviewing the metabolism of melanin synthesis, we hope to highlight outstanding questions and opportunities for future research that could improve patient outcomes in pigmentary and oncologic disease settings.
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Affiliation(s)
- Marelize Snyman
- Dermatology Department, University of Texas Southwestern Medical Center, Dallas, Texas, 75235
| | - Rachel E. Walsdorf
- Dermatology Department, University of Texas Southwestern Medical Center, Dallas, Texas, 75235
| | - Sophia N. Wix
- Dermatology Department, University of Texas Southwestern Medical Center, Dallas, Texas, 75235
| | - Jennifer G. Gill
- Dermatology Department, University of Texas Southwestern Medical Center, Dallas, Texas, 75235
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3
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Li P, Zhou J, Wang T, Li J, Wu W. Capsiate ameliorates secondary hyperparathyroidism by improving insulin sensitivity and inhibiting angiogenesis. J Cell Mol Med 2024; 28:e18202. [PMID: 38591872 PMCID: PMC11003359 DOI: 10.1111/jcmm.18202] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2023] [Revised: 02/10/2024] [Accepted: 02/20/2024] [Indexed: 04/10/2024] Open
Abstract
Secondary hyperparathyroidism has a significant impact on the overall well-being of the body. Capsiates, known for their antioxidant and metabolic properties, have emerged as a promising alternative treatment for secondary hyperparathyroidism. This study aims to evaluate the effects and mechanisms of capsiates in the treatment of secondary hyperparathyroidism. To achieve our research objectives, we conducted a study on patients' serum and examined changes in metabolic markers using serum metabolomics. We induced secondary hyperparathyroidism in rat through dietary intervention and divided them into four groups. The first group, referred to as the Parathyroid Hormone (PTH) group, received a low-calcium and high-phosphate diet (0.2% calcium, 1.2% phosphorus). The second group served as the control group, receiving a standard phosphate and calcium diet (0.6% calcium, 0.6% phosphorus). The third group, called the capsiates group, consisted of rat from the control group treated with capsiates (intraperitoneal injection of 2 mg/kg capsiates for 2 weeks after 2 weeks of dietary intervention). The fourth group was the capsiates-treated PTH group. Subsequently, we conducted ribose nucleic acid (RNA) sequencing on parathyroid gland cells and evaluated serum thyroxine levels, oxidative stress, expression of proteins associated with vascular neogenesis, measurement of SOD, GSH and 3-nitrotyrosine, micro-CT and histological staining. The serum metabolomic data revealed a significant decrease in capsiate levels in the secondary hyperparathyroidism group. Administration of capsiates to PTH rat resulted in increased calcium levels compared to the PTH group. Additionally, the PTH + Capsiates group showed significantly lower levels of PTH and phosphate compared to the PTH group. The PTH group exhibited a notable increase in the quantity and size of mitochondria compared to the control group. Following capsiates administration to the PTH group, there was a significant reduction in the number of mitochondria and length of microvilli, but an increase in the size of mitochondria compared to the PTH group. Sequencing analysis revealed that vascular endothelial growth factor (VEGF) and Vascular Endothelial Growth Factor Receptor 1 (VEGFR1) play crucial roles in this process. Vascular-related variables and downstream signalling were significantly elevated in hyperthyroidism and were alleviated with capsaicin treatment. Finally, combining capsiates with the PTH group improved bone mineral density, Tb.N, BV.TV, Cs.Th, Tt.Ar, OPG, Ob.TV and Oc.TV, as well as the mineral apposition rate, but significantly decreased Tb.Sp and Receptor Activator for Nuclear Factor-κ B Ligand (RANKL) compared to the PTH group. The findings suggest that capsiates can improve secondary hyperparathyroidism and ameliorated osteoporosis outcomes by inhibiting angiogenesis and reducing oxidative stress.
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Affiliation(s)
- Peiting Li
- Department of Plastic SurgeryThe Third Xiangya Hospital, Central South UniversityChangshaChina
| | - Jianda Zhou
- Department of Plastic SurgeryThe Third Xiangya Hospital, Central South UniversityChangshaChina
| | - Tianyin Wang
- Transplantation CenterThe Third Xiangya Hospital, Central South UniversityChangshaChina
| | - Jun Li
- Department of Breast Thyroid SurgeryThe Third Xiangya Hospital, Central South UniversityChangshaChina
| | - Wei Wu
- Department of Breast Thyroid SurgeryThe Third Xiangya Hospital, Central South UniversityChangshaChina
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4
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Fernandes C, Casadevall A, Gonçalves T. Mechanisms of Alternaria pathogenesis in animals and plants. FEMS Microbiol Rev 2023; 47:fuad061. [PMID: 37884396 DOI: 10.1093/femsre/fuad061] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2023] [Revised: 09/18/2023] [Accepted: 10/25/2023] [Indexed: 10/28/2023] Open
Abstract
Alternaria species are cosmopolitan fungi darkly pigmented by melanin that infect numerous plant species causing economically important agricultural spoilage of various food crops. Alternaria spp. also infect animals, being described as entomopathogenic fungi but also infecting warm-blooded animals, including humans. Their clinical importance in human health, as infection agents, lay in the growing number of immunocompromised patients. Moreover, Alternaria spp. are considered some of the most abundant and potent sources of airborne sensitizer allergens causing allergic respiratory diseases, as severe asthma. Among the numerous strategies deployed by Alternaria spp. to attack their hosts, the production of toxins, carrying critical concerns to public health as food contaminant, and the production of hydrolytic enzymes such as proteases, can be highlighted. Alternaria proteases also trigger allergic symptoms in individuals with fungal sensitization, acting as allergens and facilitating antigen access to the host subepithelium. Here, we review the current knowledge about the mechanisms of Alternaria pathogenesis in plants and animals, the strategies used by Alternaria to cope with the host defenses, and the involvement Alternaria allergens and mechanisms of sensitization.
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Affiliation(s)
- Chantal Fernandes
- CNC-UC - Center for Neuroscience and Cell Biology of Coimbra, Rua Larga, 3004-504 Coimbra, Portugal
| | - Arturo Casadevall
- Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Wolfe Street, Room E5132, Baltimore, Maryland 21205, USA
| | - Teresa Gonçalves
- CNC-UC - Center for Neuroscience and Cell Biology of Coimbra, Rua Larga, 3004-504 Coimbra, Portugal
- FMUC - Faculty of Medicine, University of Coimbra, Rua Larga, 3004-504 Coimbra, Portugal
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5
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Abd El-Azeem SA, Alajmi AM. Study of the Effect of Gamma Rays on the Melanin Physical Properties and Its Release from Liposomes. ARABIAN JOURNAL FOR SCIENCE AND ENGINEERING 2023. [DOI: 10.1007/s13369-023-08144-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/21/2022] [Accepted: 07/16/2023] [Indexed: 09/02/2023]
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6
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Mobuchon L, Derrien AC, Houy A, Verrier T, Pierron G, Cassoux N, Milder M, Deleuze JF, Boland A, Scelo G, Cancel-Tassin G, Cussenot O, Rodrigues M, Noirel J, Machiela MJ, Stern MH. Different Pigmentation Risk Loci for High-Risk Monosomy 3 and Low-Risk Disomy 3 Uveal Melanomas. J Natl Cancer Inst 2022; 114:302-309. [PMID: 34424336 PMCID: PMC8826635 DOI: 10.1093/jnci/djab167] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2021] [Revised: 07/06/2021] [Accepted: 08/19/2021] [Indexed: 11/12/2022] Open
Abstract
BACKGROUND Uveal melanoma (UM), a rare malignant tumor of the eye, is predominantly observed in populations of European ancestry. UMs carrying a monosomy 3 (M3) frequently relapse mainly in the liver, whereas UMs with disomy 3 (D3) are associated with more favorable outcome. Here, we explored the UM genetic predisposition factors in a large genome-wide association study (GWAS) of 1142 European UM patients and 882 healthy controls . METHODS We combined 2 independent datasets (Global Screening Array) with the dataset described in a previously published GWAS in UM (Omni5 array), which were imputed separately and subsequently merged. Patients were stratified according to their chromosome 3 status, and identified UM risk loci were tested for differential association with M3 or D3 subgroups. All statistical tests were 2-sided. RESULTS We recapitulated the previously identified risk locus on chromosome 5 on CLPTM1L (rs421284: odds ratio [OR] =1.58, 95% confidence interval [CI] = 1.35 to 1.86; P = 1.98 × 10-8) and identified 2 additional risk loci involved in eye pigmentation: IRF4 locus on chromosome 6 (rs12203592: OR = 1.76, 95% CI = 1.44 to 2.16; P = 3.55 × 10-8) and HERC2 locus on chromosome 15 (rs12913832: OR= 0.57, 95% CI = 0.48 to 0.67; P = 1.88 × 10-11). The IRF4 rs12203592 single-nucleotide polymorphism was found to be exclusively associated with risk for the D3 UM subtype (ORD3 = 2.73, 95% CI = 1.87 to 3.97; P = 1.78 × 10-7), and the HERC2 rs12913832 single-nucleotide polymorphism was exclusively associated with risk for the M3 UM subtype (ORM3 = 2.43, 95% CI = 1.79 to 3.29; P = 1.13 × 10-8). However, the CLPTM1L risk locus was equally statistically significant in both subgroups. CONCLUSIONS This work identified 2 additional UM risk loci known for their role in pigmentation. Importantly, we demonstrate that UM tumor biology and metastatic potential are influenced by patients' genetic backgrounds.
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Affiliation(s)
- Lenha Mobuchon
- Inserm U830, DNA Repair and Uveal Melanoma (D.R.U.M), Equipe Labellisée par la Ligue Nationale Contre le Cancer, Institut Curie, PSL Research University, Paris, France
| | - Anne-Céline Derrien
- Inserm U830, DNA Repair and Uveal Melanoma (D.R.U.M), Equipe Labellisée par la Ligue Nationale Contre le Cancer, Institut Curie, PSL Research University, Paris, France
| | - Alexandre Houy
- Inserm U830, DNA Repair and Uveal Melanoma (D.R.U.M), Equipe Labellisée par la Ligue Nationale Contre le Cancer, Institut Curie, PSL Research University, Paris, France
| | - Thibault Verrier
- Inserm U830, DNA Repair and Uveal Melanoma (D.R.U.M), Equipe Labellisée par la Ligue Nationale Contre le Cancer, Institut Curie, PSL Research University, Paris, France
| | - Gaëlle Pierron
- Somatic Genetic Unit, Department of Genetics, Institut Curie, PSL Research University, Paris, France
| | - Nathalie Cassoux
- Department of Ocular Oncology, Institut Curie, Paris, France
- Faculty of Medicine, University of Paris Descartes, Paris, France
| | - Maud Milder
- Inserm CIC BT 1418, Institut Curie, PSL Research University, Paris, France
| | - Jean-François Deleuze
- Université Paris-Saclay, CEA, Centre National de Recherche en Génomique Humaine, Evry, France
| | - Anne Boland
- Université Paris-Saclay, CEA, Centre National de Recherche en Génomique Humaine, Evry, France
| | - Ghislaine Scelo
- International Agency for Research on Cancer (IARC), Lyon, France
- Cancer Epidemiology Unit, Department of Medical Sciences, University of Turin, Turin, Italy
| | - Géraldine Cancel-Tassin
- CeRePP, Tenon Hospital, Paris, France
- Sorbonne University, GRC n°5 Predictive Onco-Urology, AP-HP, Tenon Hospital, Paris, France
| | - Olivier Cussenot
- CeRePP, Tenon Hospital, Paris, France
- Sorbonne University, GRC n°5 Predictive Onco-Urology, AP-HP, Tenon Hospital, Paris, France
| | - Manuel Rodrigues
- Inserm U830, DNA Repair and Uveal Melanoma (D.R.U.M), Equipe Labellisée par la Ligue Nationale Contre le Cancer, Institut Curie, PSL Research University, Paris, France
- Department of Medical Oncology, Institut Curie, PSL Research University, Paris, France
| | - Josselin Noirel
- Laboratoire GBCM (EA7528), CNAM, HESAM Université, Paris, France
| | - Mitchell J Machiela
- Division of Cancer Epidemiology and Genetics, National Cancer Institute, Bethesda, MD 20892, USA
| | - Marc-Henri Stern
- Inserm U830, DNA Repair and Uveal Melanoma (D.R.U.M), Equipe Labellisée par la Ligue Nationale Contre le Cancer, Institut Curie, PSL Research University, Paris, France
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7
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Pheomelanin Effect on UVB Radiation-Induced Oxidation/Nitration of l-Tyrosine. Int J Mol Sci 2021; 23:ijms23010267. [PMID: 35008693 PMCID: PMC8745751 DOI: 10.3390/ijms23010267] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2021] [Revised: 12/20/2021] [Accepted: 12/23/2021] [Indexed: 11/25/2022] Open
Abstract
Pheomelanin is a natural yellow-reddish sulfur-containing pigment derived from tyrosinase-catalyzed oxidation of tyrosine in presence of cysteine. Generally, the formation of melanin pigments is a protective response against the damaging effects of UV radiation in skin. However, pheomelanin, like other photosensitizing substances, can trigger, following exposure to UV radiation, photochemical reactions capable of modifying and damaging cellular components. The photoproperties of this natural pigment have been studied by analyzing pheomelanin effect on oxidation/nitration of tyrosine induced by UVB radiation at different pH values and in presence of iron ions. Photoproperties of pheomelanin can be modulated by various experimental conditions, ranging from the photoprotection to the triggering of potentially damaging photochemical reactions. The study of the photomodification of l-Tyrosine in the presence of the natural pigment pheomelanin has a special relevance, since this tyrosine oxidation/nitration pathway can potentially occur in vivo in tissues exposed to sunlight and play a role in the mechanisms of tissue damage induced by UV radiation.
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8
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Cuba JPB, Alves GGB, Galindo LA, Paulin JV, Batagin-Neto A. Sulfonated melanin derivatives: theoretical evaluation of local reactivities and chemical structures. J Mol Model 2021; 27:362. [PMID: 34825273 DOI: 10.1007/s00894-021-04982-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2021] [Accepted: 11/12/2021] [Indexed: 10/19/2022]
Abstract
Melanins are natural macromolecules present in several organisms responsible for photoprotection, photosensitivity, ion chelation, and thermoregulation. Such materials have attracted attention due to their interesting electronic properties, which suggest their possible application in biocompatible devices. However, the low typical solubility of traditional melanins does not allow the production of good quality thin films. In this sense, soluble compounds obtained via alternative synthetic routes, for instance, via levodopa (L-DOPA) oxidation in sulfonated solvents (S-melanins), can be considered interesting technological materials. Despite this, the structural and electronic features of these compounds are not fully understood. In this context, here we present a theoretical study on the local reactivities of S-melanin building blocks to better understand possible mechanisms involved in its synthesis and propose extended structures of this material. For this purpose, condensed-to-atoms Fukui indices were evaluated in the framework of the density functional theory (DFT). The obtained results show that the different side groups present in S-melanins do not significantly influence the reactivity of the compound in relation to non-functionalized melanins, indicating that both materials can present similar macroscopic structures.
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Affiliation(s)
- João P B Cuba
- São Paulo State University (UNESP), Campus of Itapeva, Itapeva, SP, 18409-010, Brazil
| | - Gabriel G B Alves
- School of Sciences, POSMAT, São Paulo State University (UNESP), Bauru, SP, 17033-360, Brazil.
| | - Levy A Galindo
- School of Sciences, POSMAT, São Paulo State University (UNESP), Bauru, SP, 17033-360, Brazil
| | - João V Paulin
- Brazilian Nanotechnology National Laboratory (LNNano), Brazilian Center for Research in Energy and Materials (CNPEM), Campinas, SP, 13083970, Brazil
| | - Augusto Batagin-Neto
- São Paulo State University (UNESP), Campus of Itapeva, Itapeva, SP, 18409-010, Brazil.,School of Sciences, POSMAT, São Paulo State University (UNESP), Bauru, SP, 17033-360, Brazil
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9
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Production and characterization of crude laccase from Irpex sp. JS7 that decolorizes synthetic and natural melanin. Folia Microbiol (Praha) 2021; 66:1039-1046. [PMID: 34346036 DOI: 10.1007/s12223-021-00904-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2021] [Accepted: 07/21/2021] [Indexed: 10/20/2022]
Abstract
The JS7 strain, isolated from an old forest tree, produces extracellular enzymes that decolorize synthetic and natural melanin from human hair. Phylogenetic analysis based on the internal transcribed spacer (ITS) sequence indicated that JS7 belongs to the genus Irpex. The JS7 strain has laccase activity while it lacks manganese and lignin peroxidase activity, which suggests that the JS7 strain melanin decolorization activity originated from laccase. Laccase production from the Irpex sp. JS7 improved three-fold in the presence of veratryl alcohol, compared to without an inducer. The optimum pH and temperature for melanin decolorization were 7.5 and 40 °C, respectively. The crude enzyme half-life at 25 °C was about 100 days, and it had high storage stability. The melanin decolorization reaction rate by the crude enzyme conformed to typical enzyme kinetic principles. In the presence of syringaldehyde as a redox mediator, the melanin decolorization rate was 75% within 5 days, similar to the decolorization percentage obtained using the enzyme alone. Based on these results, the Irpex sp. JS7 enzyme is suitable for use in melanin decolorization by whitening agents in the cosmetics industry.
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10
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Lasisi T. The constraints of racialization: How classification and valuation hinder scientific research on human variation. AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY 2021; 175:376-386. [PMID: 33675042 DOI: 10.1002/ajpa.24264] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/28/2020] [Revised: 02/15/2021] [Accepted: 02/17/2021] [Indexed: 12/18/2022]
Abstract
Human biological variation has historically been studied through the lens of racialization. Despite a general shift away from the use of overt racial terminologies, the underlying racialized frameworks used to describe and understand human variation still remain. Even in relatively recent anthropological and biomedical work, we can observe clear manifestations of such racial thinking. This paper shows how classification and valuation are two specific processes which facilitate racialization and hinder attempts to move beyond such frameworks. The bias induced by classification distorts descriptions of phenotypic variation in a way that erroneously portrays European populations as more variable than others. Implicit valuation occurs in tandem with classification and produces narratives of superiority/inferiority for certain phenotypic variants without an objective biological basis. The bias of racialization is a persistent impediment stemming from the inheritance of scientific knowledge developed under explicitly racial paradigms. It is also an internalized cognitive distortion cultivated through socialization in a world where racialization is inescapable. Though undeniably challenging, this does not present an insurmountable barrier, and this bias can be mitigated through the critical evaluation of past work, the active inclusion of marginalized perspectives, and the direct confrontation of institutional structures enforcing racialized paradigms.
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Affiliation(s)
- Tina Lasisi
- Department of Anthropology, Pennsylvania State University, State College, Pennsylvania, USA
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11
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Shankar N, Guimarães AO, Napoli E, Giulivi C. Forensic determination of hair deposition time in crime scenes using electron paramagnetic resonance. J Forensic Sci 2020; 66:72-82. [PMID: 32986869 DOI: 10.1111/1556-4029.14570] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2020] [Revised: 08/06/2020] [Accepted: 08/18/2020] [Indexed: 11/28/2022]
Abstract
Several types of biological samples, including hair strands, are found at crime scenes. Apart from the identification of the value and the contributor of the probative evidence, it is important to prove that the time of shedding of hair belonging to a suspect or victim matches the crime window. To this end, to estimate the ex vivo aging of hair, we evaluated time-dependent changes in melanin-derived free radicals in blond, brown, and black hairs by using electron paramagnetic resonance spectroscopy (EPR). Hair strands aged under controlled conditions (humidity 40%, temperature 20-22°C, indirect light, with 12/12 hour of light/darkness cycles) showed a time-dependent decay of melanin-derived radicals. The half-life of eumelanin-derived radicals in hair under our experimental settings was estimated at 22 ± 2 days whereas that of pheomelanin was about 2 days suggesting better stabilization of unpaired electrons by eumelanin. Taken together, this study provides a reference for future forensic studies on determination of degradation of shed hair in a crime scene by following eumelanin radicals by utilizing the non-invasive, non-destructive, and highly specific EPR technique.
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Affiliation(s)
- Nikhita Shankar
- Department of Molecular Biosciences, School of Veterinary Medicine, University of California Davis, Davis, CA, USA
| | - André O Guimarães
- Department of Molecular Biosciences, School of Veterinary Medicine, University of California Davis, Davis, CA, USA.,Laboratório de Ciências Físicas, Universidade Estadual do Norte Fluminense, Campos dos Goytacazes, RJ, Brazil
| | - Eleonora Napoli
- Department of Molecular Biosciences, School of Veterinary Medicine, University of California Davis, Davis, CA, USA
| | - Cecilia Giulivi
- Department of Molecular Biosciences, School of Veterinary Medicine, University of California Davis, Davis, CA, USA.,MIND Institute, University of California Davis Medical Center, Sacramento, CA, USA
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12
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Houtzagers LE, Wierenga APA, Ruys AAM, Luyten GPM, Jager MJ. Iris Colour and the Risk of Developing Uveal Melanoma. Int J Mol Sci 2020; 21:E7172. [PMID: 32998469 PMCID: PMC7583924 DOI: 10.3390/ijms21197172] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2020] [Revised: 09/15/2020] [Accepted: 09/24/2020] [Indexed: 02/07/2023] Open
Abstract
Uveal melanoma (UM) is a global disease which especially occurs in elderly people. Its incidence varies widely between populations, with the highest incidence among Caucasians, and a South-to-North increase in Europe. As northern Europeans often have blond hair and light eyes, we wondered whether iris colour may be a predisposing factor for UM and if so, why. We compared the distribution of iris colour between Dutch UM patients and healthy Dutch controls, using data from the Rotterdam Study (RS), and reviewed the literature regarding iris colour. We describe molecular mechanisms that might explain the observed associations. When comparing a group of Dutch UM patients with controls, we observed that individuals from Caucasian ancestry with a green/hazel iris colour (Odds Ratio (OR) = 3.64, 95% Confidence Interval (CI) 2.57-5.14) and individuals with a blue/grey iris colour (OR = 1.38, 95% CI 1.04-1.82) had a significantly higher crude risk of UM than those with brown eyes. According to the literature, this may be due to a difference in the function of pheomelanin (associated with a light iris colour) and eumelanin (associated with a brown iris colour). The combination of light-induced stress and aging may affect pheomelanin-carrying melanocytes in a different way than eumelanin-carrying melanocytes, increasing the risk of developing a malignancy.
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Affiliation(s)
| | | | | | | | - Martine J. Jager
- Department of Ophthalmology, Leiden University Medical Center, Albinusdreef 2, 2333 ZA Leiden, The Netherlands; (A.P.A.W.); (A.A.M.R.); (G.P.M.L.)
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13
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Zadlo A, Mokrzyński K, Ito S, Wakamatsu K, Sarna T. The influence of iron on selected properties of synthetic pheomelanin. Cell Biochem Biophys 2020; 78:181-189. [PMID: 32451722 PMCID: PMC7266848 DOI: 10.1007/s12013-020-00918-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2020] [Accepted: 05/08/2020] [Indexed: 11/29/2022]
Abstract
It is believed that while eumelanin plays photoprotective and antioxidant role in pigmented tissues, pheomelanin being more photoreactive could behave as a phototoxic agent. Although the metal ion-sequestering ability of melanin might be protective, transition metal ions present in natural melanins could affect their physicochemical properties. The aim of this research was to study iron binding by pheomelanin and analyze how such a binding affects selected properties of the melanin. Synthetic pheomelanin (CDM), prepared by enzymatic oxidation of DOPA in the presence of cysteine was analyzed by electron paramagnetic resonance (EPR) spectroscopy, spectrophotometry, chemical analysis, and time-resolved measurements of singlet oxygen phosphorescence. Iron broadened EPR signal of melanin and increased its optical absorption. Iron bound to melanin exhibited EPR signal at g = 4.3, typical for high-spin iron (III). Iron bound to melanin significantly altered the kinetics of melanin photodegradation, which in turn modified the accessibility and stability of the melanin–iron complexes as indicated by the release of iron from melanin induced by diethylenetriaminepentaacetic acid and KCN. Although bound to melanin iron little affects initial stages of photodegradation of CDM, the effect of iron becomes more pronounced at later stages of melanin photolysis.
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Affiliation(s)
- Andrzej Zadlo
- Department of Biophysics, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Krakow, Poland.
| | - Krystian Mokrzyński
- Department of Biophysics, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Krakow, Poland
| | - Shosuke Ito
- Department of Chemistry, Fujita Health University School of Medical Sciences, Toyoake, Japan
| | - Kazumasa Wakamatsu
- Department of Chemistry, Fujita Health University School of Medical Sciences, Toyoake, Japan
| | - Tadeusz Sarna
- Department of Biophysics, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Krakow, Poland
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14
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Martínez LM, Martinez A, Gosset G. Production of Melanins With Recombinant Microorganisms. Front Bioeng Biotechnol 2019; 7:285. [PMID: 31709247 PMCID: PMC6821874 DOI: 10.3389/fbioe.2019.00285] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2019] [Accepted: 10/07/2019] [Indexed: 11/16/2022] Open
Abstract
The melanins constitute a diverse group of natural products found in most organisms, having functions related to protection against chemical and physical stresses. These products originate from the enzyme-catalyzed oxidation of phenolic and indolic substrates that polymerize to yield melanins, which include eumelanin, pheomelanin, pyomelanin, and the allomelanins. The enzymes involved in melanin formation belong mainly to the tyrosinase and laccase protein families. The melanins are polymeric materials having applications in the pharmaceutical, cosmetic, optical, and electronic industries. The biotechnological production of these polymers is an attractive alternative to obtaining them by extraction from plant or animal material, where they are present at low concentrations. Several species of microorganisms have been identified as having a natural melanogenic capacity. The development and optimization of culture conditions with these organisms has resulted in processes for generating melanins. These processes are based on the conversion of melanin precursors present in the culture medium to the corresponding polymers. With the application of genetic engineering techniques, it has become possible to overexpress genes encoding enzymes involved in melanin formation, mostly tyrosinases, leading to an improvement in the productivity of melanogenic organisms, as well as allowing the generation of novel recombinant microbial strains that can produce diverse types of melanins. Furthermore, the metabolic engineering of microbial hosts by modifying pathways related to the supply of melanogenic precursors has resulted in strains with the capacity of performing the total synthesis of melanins from simple carbon sources in the scale of grams. In this review, the latest advances toward the generation of recombinant melanin production strains and production processes are summarized and discussed.
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Affiliation(s)
- Luz María Martínez
- Departamento de Ingeniería Celular y Biocatálisis, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Mexico
| | - Alfredo Martinez
- Departamento de Ingeniería Celular y Biocatálisis, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Mexico
| | - Guillermo Gosset
- Departamento de Ingeniería Celular y Biocatálisis, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Mexico
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15
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Seleem AA. Induction of hyperpigmentation and heat shock protein 70 response to the toxicity of methomyl insecticide during the organ development of the Arabian toad, Bufo arabicus (Heyden,1827). J Histotechnol 2019; 42:104-115. [PMID: 31492089 DOI: 10.1080/01478885.2019.1619653] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Methomyl (MET) is a carbamate insecticide which is used as a substitute for organophosphorus compounds to protect crops against insects. The present study aims to evaluate the cytoprotection response of pigment cells and heat shock protein 70 (HSP70) after exposure to MET during the tadpole developmental stages of the Arabian toad, Bufo arabicus. Three developmental larval stages of the toad were selected and divided into two groups; Control and MET-exposed (MET-EX) tadpoles (10ppm). MET-EX tadpoles showed an increased number of pigment cells in the liver, kidney, anterior eye chamber, and skin tissues as compared to the control. The glycogen content in the developing liver and muscles (myotomes) of MET-EX tadpoles was decreased as compared to the control. In the MET-EX tadpoles, immunohistochemical staining showed an increase of HSP70 expression in the liver hepatocytes, the nucleated red blood cells (nRBC) in kidney glomeruli, the iridocorneal angle of anterior eye chamber, and the skin as compared to the control. The current study concluded that pigment cells and HSP70 represented a cytoprotecting response against MET insecticide during the organ development of B. arabicas tadpoles. Therefore, MET use should be regularly monitored in the environment to protect animals and human from exposure to this insecticide.
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Affiliation(s)
- Amin Abdou Seleem
- Zoology Department, Faculty of Science, Sohag University , Sohag , Egypt.,Biology Department, Faculty of Science and Arts, Al-Ula, Taibah University , Medina , Kingdom of Saudi Arabia
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16
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Baldea I, Giurgiu L, Teacoe ID, Olteanu DE, Olteanu FC, Clichici S, Filip GA. Photodynamic Therapy in Melanoma - Where do we Stand? Curr Med Chem 2019; 25:5540-5563. [PMID: 29278205 DOI: 10.2174/0929867325666171226115626] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2017] [Revised: 11/21/2017] [Accepted: 11/29/2017] [Indexed: 12/19/2022]
Abstract
BACKGROUND Malignant melanoma is one of the most aggressive malignant tumors, with unpredictable evolution. Despite numerous therapeutic options, like chemotherapy, BRAF inhibitors and immunotherapy, advanced melanoma prognosis remains severe. Photodynamic therapy (PDT) has been successfully used as the first line or palliative therapy for the treatment of lung, esophageal, bladder, non melanoma skin and head and neck cancers. However, classical PDT has shown some drawbacks that limit its clinical application in melanoma. OBJECTIVE The most important challenge is to overcome melanoma resistance, due to melanosomal trapping, presence of melanin, enhanced oxidative stress defense, defects in the apoptotic pathways, immune evasion, neoangiogenesis stimulation. METHOD In this review we considered: (1) main signaling molecular pathways deregulated in melanoma as potential targets for personalized therapy, including PDT, (2) results of the clinical studies regarding PDT of melanoma, especially advanced metastatic stage, (3) progresses made in the design of anti-melanoma photosensitizers (4) inhibition of tumor neoangiogenesis, as well as (5) advantages of the derived therapies like photothermal therapy, sonodynamic therapy. RESULTS PDT represents a promising alternative palliative treatment for advanced melanoma patients, mainly due to its minimal invasive character and low side effects. Efficient melanoma PDT requires: (1) improved, tumor targeted, NIR absorbing photosensitizers, capable of inducing high amounts of different ROS inside tumor and vasculature cells, possibly allowing a theranostic approach; (2) an efficient adjuvant immune therapy. CONCLUSION Combination of PDT with immune stimulation might be the key to overcome the melanoma resistance and to obtain better, sustainable clinical results.
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Affiliation(s)
- Ioana Baldea
- Physiology Department, University of Medicine and Pharmacy, Iuliu Hatieganu, Cluj-Napoca, Romania
| | - Lorin Giurgiu
- Physiology Department, University of Medicine and Pharmacy, Iuliu Hatieganu, Cluj-Napoca, Romania
| | - Ioana Diana Teacoe
- Physiology Department, University of Medicine and Pharmacy, Iuliu Hatieganu, Cluj-Napoca, Romania
| | - Diana Elena Olteanu
- Physiology Department, University of Medicine and Pharmacy, Iuliu Hatieganu, Cluj-Napoca, Romania
| | - Florin Catalin Olteanu
- Industrial Engineering and Management Department, Transylvania University, Brasov, Romania
| | - Simona Clichici
- Physiology Department, University of Medicine and Pharmacy, Iuliu Hatieganu, Cluj-Napoca, Romania
| | - Gabriela Adriana Filip
- Physiology Department, University of Medicine and Pharmacy, Iuliu Hatieganu, Cluj-Napoca, Romania
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17
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Pavani C, Severino D, Villa Dos Santos N, Chiarelli-Neto O, Baptista MS. Spectroscopy as a tool to evaluate hair damage and protection. Int J Cosmet Sci 2018; 40:596-603. [PMID: 30431651 DOI: 10.1111/ics.12503] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2018] [Accepted: 11/12/2018] [Indexed: 11/26/2022]
Abstract
OBJECTIVE Methods that can be used to analyse hair damage and to support a claim of hair protection are important for the cosmetic industry. There are many approaches available, but they are usually laborious and expensive. The researchers propose a simple fluorescence method that is based upon the emissive properties of damaged hair. METHODS Hair fluorescence was observed when using both fluorimetry and microscopic procedures. The method was developed by comparing native hair with hair that was damaged by UVA and visible light. RESULTS Spectroscopic properties (absorption and emission) of hair in the visible range are presented. The changes in the emissive properties of hair during irradiation were characterized and they were correlated with photobleaching, which is due to the generation of singlet oxygen. Emissions were also obtained in the hair shafts that had been previously treated with chamomile extract and this treatment was able to avoid hair bleaching. CONCLUSION The emissive properties of hair in the visible range can be used as a tool for the evaluation of hair damage and protection. This method can be useful as a tool in order to claim substantiation.
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Affiliation(s)
- C Pavani
- Programa de Pós-graduação em Biofotônica Aplicada às Ciências da Saúde, Universidade Nove de Julho (UNINOVE), São Paulo, Brasil
| | - D Severino
- Departamento de Bioquímica, Instituto de Química - Universidade de São Paulo, São Paulo, Brasil
| | - N Villa Dos Santos
- Departamento de Bioquímica, Instituto de Química - Universidade de São Paulo, São Paulo, Brasil
| | - O Chiarelli-Neto
- Departamento de Bioquímica, Instituto de Química - Universidade de São Paulo, São Paulo, Brasil
| | - M S Baptista
- Departamento de Bioquímica, Instituto de Química - Universidade de São Paulo, São Paulo, Brasil
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18
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Tanaka H, Yamashita Y, Umezawa K, Hirobe T, Ito S, Wakamatsu K. The Pro-Oxidant Activity of Pheomelanin is Significantly Enhanced by UVA Irradiation: Benzothiazole Moieties Are More Reactive than Benzothiazine Moieties. Int J Mol Sci 2018; 19:E2889. [PMID: 30249034 PMCID: PMC6213070 DOI: 10.3390/ijms19102889] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2018] [Revised: 09/22/2018] [Accepted: 09/22/2018] [Indexed: 11/18/2022] Open
Abstract
It is generally considered that eumelanin (EM) is photoprotective while pheomelanin (PM) is phototoxic. A recent study using a mouse model demonstrated that PM produces reactive oxygen species (ROS) that cause DNA damage and eventually lead to melanomagenesis. A biochemical study showed that PM possesses a pro-oxidant activity. PM consists of benzothiazine (BT) and benzothiazole (BZ) moieties, BT moieties being transformed to BZ moieties by heat or light. In this study, we compared the effects of ultraviolet A (UVA) irradiation using synthetic PMs with different BT to BZ ratios and using various coat color mouse hairs. We found that UVA irradiation of BZ-PM increased glutathione (GSH) depletion and generated more H₂O₂ than UVA irradiation of BT-PM. Non-irradiated controls did not exhibit strong pro-oxidant activities. Upon UVA irradiation, yellow mouse hairs oxidized GSH and produced H₂O₂ faster than black or albino mouse hairs. Next, to examine the mechanism of the pro-oxidant activity of BT-PM and BZ-PM, we examined the pro-oxidant activities of 7-(2-amino-2-carboxyethyl)-dihydro-1,4-benzothiazine-3-carboxylic acid (DHBTCA) and 6-(2-amino-2-carboxyethyl)-4-hydroxybenzothiazole (BZ-AA) as BT and BZ monomers, respectively. Their pro-oxidant activities were similar, but a large difference was seen in the effects of ROS scavengers, which suggests that the redox reactions may proceed via singlet oxygen in BZ-AA and via superoxide anions in DHBTCA. These results show that UVA enhances the pro-oxidant activity of PM, in particular BZ-PM.
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Affiliation(s)
- Hitomi Tanaka
- Department of Chemistry, Fujita Health University School of Health Sciences, 1-98 Dengakugakubo, Kutsukake-cho, Toyoake, Aichi 470-1192, Japan.
| | - Yui Yamashita
- Department of Chemistry, Fujita Health University School of Health Sciences, 1-98 Dengakugakubo, Kutsukake-cho, Toyoake, Aichi 470-1192, Japan.
| | - Kana Umezawa
- Department of Chemistry, Fujita Health University School of Health Sciences, 1-98 Dengakugakubo, Kutsukake-cho, Toyoake, Aichi 470-1192, Japan.
| | - Tomohisa Hirobe
- Laboratory for Cell Culture and Pathology, Shinjuku Skin Clinic, Kawase Building BF1, Shinjuku 3-17-5, Shinjuku-ku, Tokyo 160-0022, Japan.
| | - Shosuke Ito
- Department of Chemistry, Fujita Health University School of Health Sciences, 1-98 Dengakugakubo, Kutsukake-cho, Toyoake, Aichi 470-1192, Japan.
| | - Kazumasa Wakamatsu
- Department of Chemistry, Fujita Health University School of Health Sciences, 1-98 Dengakugakubo, Kutsukake-cho, Toyoake, Aichi 470-1192, Japan.
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19
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Abdelhalim MAK, Moussa SAA, Qaid HA, Al-Ayed MS. Effect of melanin on gold nanoparticle-induced hepatotoxicity and lipid peroxidation in rats. Int J Nanomedicine 2018; 13:5207-5213. [PMID: 30233181 PMCID: PMC6135214 DOI: 10.2147/ijn.s170758] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Introduction Melanin pigments are produced by melanocytes and are believed to act as antioxidants based on the belief that melanin can suppress electronically stirred states and scavenge the free radicals. Materials and methods The study was aimed to verify and prove the toxicity induced by administration of gold nanoparticles (GNPs) and to characterize the role of melanin as an antioxidant against inflammatory liver damage, oxidative stress, and lipid peroxidation induced intraperitoneally by GNPs in vivo. Results The findings from this study confirmed that administration of GNPs intraperitoneally caused liver damage in addition to producing oxidative stress and fatty acid peroxidation. The treatment of rats with melanin along with GNPs induced dramatic changes in all the measured biochemical parameters. Our data demonstrated that melanin completely inhibited inflammatory liver damage, oxidative stress, and lipid peroxidation, which was confirmed by the histological investigation of different liver sections stained by H&E. Conclusion These results suggest the beneficial use of melanin together with GNPs for alleviating its toxicity. Other studies should be implemented taking into consideration the role of melanin in comparison with other natural antioxidants.
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Affiliation(s)
| | - Sherif A Abdelmottaleb Moussa
- Committee of Radiation and Environmental Pollution Protection (CREPP), Department of Physics, College of Science, Al-Imam Mohammad Ibn Saud Islamic University (IMSIU), Riyadh, Saudi Arabia.,Biophysics Group, Biochemistry Department, Genetic Engineering and Biotechnology Division, National Research Center, Giza, Egypt
| | - Huda Ay Qaid
- Department of Physics and Astronomy, College of Science, King Saud University, Riyadh, Saudi Arabia,
| | - Mohammed Suliman Al-Ayed
- Department of Physics and Astronomy, College of Science, King Saud University, Riyadh, Saudi Arabia,
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20
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Yacout SM, McIlwain KL, Mirza SP, Gaillard ER. Characterization of Retinal Pigment Epithelial Melanin and Degraded Synthetic Melanin Using Mass Spectrometry and In Vitro Biochemical Diagnostics. Photochem Photobiol 2018; 95:183-191. [PMID: 29752877 DOI: 10.1111/php.12934] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2018] [Accepted: 04/24/2018] [Indexed: 12/14/2022]
Abstract
With increasing age, there is an observable loss of melanin in retinal pigment epithelial (RPE) cells. It is possible that degradation of the pigment contributes to the pathogenesis of retinal disease, as the cellular antioxidant material is depleted. Functionally, intact melanin maintains protective qualities, while oxidative degradation of melanin promotes reactive oxygen species (ROS) generation and formation of metabolic byproducts, such as melanolipofuscin. Understanding the structural and functional changes to RPE melanin with increasing age may contribute to a better understanding of disease progression and risk factors for conditions such as age-related macular degeneration (AMD). In this study, human donor RPE melanin is characterized using MALDI mass spectrometry to follow melanin degradation trends. In vitro models using ARPE-19 cells are used to assess photo-reactivity in repigmented cells. Significant protection against intracellular ROS produced by blue light is observed in calf melanin-pigmented cells versus unpigmented and black latex bead controls (P < 0.0001). UV-B exposure to aged human melanin-pigmented cells results in a significant increase in nitric oxide production versus control cells (P < 0.001). Peroxide-treated synthetic melanin is characterized to elucidate degradation products that may contribute to RPE cell damage.
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Affiliation(s)
- Sally M Yacout
- Department of Chemistry and Biochemistry, Northern Illinois University, DeKalb, IL
| | - Kelsey L McIlwain
- Department of Chemistry and Biochemistry, Northern Illinois University, DeKalb, IL
| | - Shama P Mirza
- Department of Chemistry and Biochemistry, University of Wisconsin-Milwaukee, Milwaukee, WI
| | - Elizabeth R Gaillard
- Department of Chemistry and Biochemistry, Northern Illinois University, DeKalb, IL.,Department of Biological Sciences, Northern Illinois University, DeKalb, IL
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21
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Montes-Avila J, Ojeda-Ayala M, López-Angulo G, Pío-León JF, Díaz-Camacho SP, Ochoa-Terán A, Delgado-Vargas F. Physicochemical properties and biological activities of melanins from the black-edible fruits Vitex mollis and Randia echinocarpa. JOURNAL OF FOOD MEASUREMENT AND CHARACTERIZATION 2018. [DOI: 10.1007/s11694-018-9812-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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22
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Roider EM, Fisher DE. Red Hair, Light Skin, and UV-Independent Risk for Melanoma Development in Humans. JAMA Dermatol 2018; 152:751-3. [PMID: 27050924 DOI: 10.1001/jamadermatol.2016.0524] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Affiliation(s)
- Elisabeth M Roider
- Department of Dermatology, Cutaneous Biology Research Center, Massachusetts General Hospital, Harvard Medical School, Charlestown, Massachusetts
| | - David E Fisher
- Department of Dermatology, Cutaneous Biology Research Center, Massachusetts General Hospital, Harvard Medical School, Charlestown, Massachusetts
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23
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Sponge-Associated Bacteria Produce Non-cytotoxic Melanin Which Protects Animal Cells from Photo-Toxicity. Appl Biochem Biotechnol 2017; 183:396-411. [DOI: 10.1007/s12010-017-2453-0] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2016] [Accepted: 03/06/2017] [Indexed: 02/05/2023]
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24
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Falade AO, Nwodo UU, Iweriebor BC, Green E, Mabinya LV, Okoh AI. Lignin peroxidase functionalities and prospective applications. Microbiologyopen 2017; 6:e00394. [PMID: 27605423 PMCID: PMC5300883 DOI: 10.1002/mbo3.394] [Citation(s) in RCA: 114] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2016] [Revised: 06/18/2016] [Accepted: 06/28/2016] [Indexed: 11/18/2022] Open
Abstract
Ligninolytic extracellular enzymes, including lignin peroxidase, are topical owing to their high redox potential and prospective industrial applications. The prospective applications of lignin peroxidase span through sectors such as biorefinery, textile, energy, bioremediation, cosmetology, and dermatology industries. The litany of potentials attributed to lignin peroxidase is occasioned by its versatility in the degradation of xenobiotics and compounds with both phenolic and non-phenolic constituents. Over the years, ligninolytic enzymes have been studied however; research on lignin peroxidase seems to have been lagging when compared to other ligninolytic enzymes which are extracellular in nature including laccase and manganese peroxidase. This assertion becomes more pronounced when the application of lignin peroxidase is put into perspective. Consequently, a succinct documentation of the contemporary functionalities of lignin peroxidase and, some prospective applications of futuristic relevance has been advanced in this review. Some articulated applications include delignification of feedstock for ethanol production, textile effluent treatment and dye decolourization, coal depolymerization, treatment of hyperpigmentation, and skin-lightening through melanin oxidation. Prospective application of lignin peroxidase in skin-lightening functions through novel mechanisms, hence, it holds high value for the cosmetics sector where it may serve as suitable alternative to hydroquinone; a potent skin-lightening agent whose safety has generated lots of controversy and concern.
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Affiliation(s)
- Ayodeji O. Falade
- SAMRC Microbial Water Quality Monitoring CentreUniversity of Fort HareAliceSouth Africa
- Applied and Environmental Microbiology Research Group (AEMREG)Department of Biochemistry and MicrobiologyUniversity of Fort HareAliceSouth Africa
| | - Uchechukwu U. Nwodo
- SAMRC Microbial Water Quality Monitoring CentreUniversity of Fort HareAliceSouth Africa
- Applied and Environmental Microbiology Research Group (AEMREG)Department of Biochemistry and MicrobiologyUniversity of Fort HareAliceSouth Africa
| | - Benson C. Iweriebor
- SAMRC Microbial Water Quality Monitoring CentreUniversity of Fort HareAliceSouth Africa
- Applied and Environmental Microbiology Research Group (AEMREG)Department of Biochemistry and MicrobiologyUniversity of Fort HareAliceSouth Africa
| | - Ezekiel Green
- SAMRC Microbial Water Quality Monitoring CentreUniversity of Fort HareAliceSouth Africa
- Applied and Environmental Microbiology Research Group (AEMREG)Department of Biochemistry and MicrobiologyUniversity of Fort HareAliceSouth Africa
| | - Leonard V. Mabinya
- SAMRC Microbial Water Quality Monitoring CentreUniversity of Fort HareAliceSouth Africa
- Applied and Environmental Microbiology Research Group (AEMREG)Department of Biochemistry and MicrobiologyUniversity of Fort HareAliceSouth Africa
| | - Anthony I. Okoh
- SAMRC Microbial Water Quality Monitoring CentreUniversity of Fort HareAliceSouth Africa
- Applied and Environmental Microbiology Research Group (AEMREG)Department of Biochemistry and MicrobiologyUniversity of Fort HareAliceSouth Africa
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25
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Song S, Yang L, Ye M, Chen X, Shi F, Shaikh F. Antioxidant activity of a Lachnum YM226 melanin-iron complex and its influence on cytokine production in mice with iron deficiency anemia. Food Funct 2016; 7:1508-14. [PMID: 26887341 DOI: 10.1039/c5fo01274k] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The present study aims to investigate the protective effects of an orally administered Lachnum YM226 melanin-iron complex (LM-Fe) against iron deficiency anemia (IDA) in mice. The IDA mouse model was established by feeding mice with iron-deficient food. Different doses of LM-Fe were given to the anaemic mice via intragastric administration, with FeCl3 and FeSO4 used as positive controls. After the iron supplement administration, it was observed that LM-Fe could significantly improve the decreased haemoglobin (Hb) level, and normalize the serum iron (SI) level, total iron-binding capacity (TIBC) and serum ferritin (SF) of the anaemic mice in a dose-dependent manner. In addition, treatment with LM-Fe significantly increased the antioxidant enzyme activities of superoxidase dismutase (SOD), catalase (CAT) and glutathione peroxidase (GSH-Px) in plasma to normal or better. Furthermore, the levels of tumour necrosis factor-α (TNF-α), interleukin-1β (IL-1β) and interleukin-6 (IL-6) were obviously decreased in the LM-Fe supplemented groups compared with the model group, while the level of interleukin-2 (IL-2) was significantly increased. In conclusion, LM-Fe was efficient at ameliorating the anemia symptoms, improving the activities of antioxidant enzymes and adjusting the immune dysfunction of anaemic mice. Thus, these results demonstrated that LM-Fe might be exploited as an efficient and multifunctional iron supplement.
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Affiliation(s)
- Sheng Song
- College of Biotechnology and Food Engineering, Hefei University of Technology, Hefei 230009, China.
| | - Liu Yang
- College of Biotechnology and Food Engineering, Hefei University of Technology, Hefei 230009, China.
| | - Ming Ye
- College of Biotechnology and Food Engineering, Hefei University of Technology, Hefei 230009, China.
| | - Xue Chen
- Department of Chemical Engineering and Food Processing, Xuancheng Campus, Hefei University of Technology, Xuancheng 242000, China
| | - Fang Shi
- College of Biotechnology and Food Engineering, Hefei University of Technology, Hefei 230009, China.
| | - Farnaz Shaikh
- College of Biotechnology and Food Engineering, Hefei University of Technology, Hefei 230009, China.
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26
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Kim BS, Blaghen M, Hong HS, Lee KM. Purification and characterization of a melanin biodegradation enzyme fromGeotrichumsp. Int J Cosmet Sci 2016; 38:622-626. [DOI: 10.1111/ics.12337] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2016] [Accepted: 04/30/2016] [Indexed: 11/26/2022]
Affiliation(s)
- B. S. Kim
- Bonecell Biotech Inc.; 77, Dunsan-dong Seo-gu Daejeon 302-120 Korea
- Department Molecular Biology; College of Natural Science; Chonbuk National University; Jeonju 561-756 Korea
| | - M. Blaghen
- Laboratory of Microbiology; Biotechnology and Environment; Faculty of Sciences; University Hassan II; Casablanca 20100 Morocco
| | - H.-S. Hong
- CheBiGen Inc.; Deokjin-gu Jeonju Chonbuk 561-202 Korea
| | - K.-M. Lee
- Department Molecular Biology; College of Natural Science; Chonbuk National University; Jeonju 561-756 Korea
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27
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Zhang B, Sun Z, Bai Y, Zhuang H, Ge D, Shi W, Sun Y. One-step deposition of a melanin-like polymer on individual Escherichia coli cells exhibiting a special UV resistance effect. RSC Adv 2016. [DOI: 10.1039/c6ra12307d] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Melanin-like polydopamine encapsulated E. coli cells could retained cells viability, inhibited cell division and protected cells from UV radiation. These provide both fundamental research and applications of cell encapsulation for UV resistance.
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Affiliation(s)
- Bai Zhang
- Department of Biomaterials
- Fujian Key Laboratory of Materials Genome
- College of Materials
- Xiamen University
- Xiamen 361005
| | - Zhou Sun
- Department of Biomaterials
- Fujian Key Laboratory of Materials Genome
- College of Materials
- Xiamen University
- Xiamen 361005
| | - Yuting Bai
- Department of Biomaterials
- Fujian Key Laboratory of Materials Genome
- College of Materials
- Xiamen University
- Xiamen 361005
| | - Hanqiong Zhuang
- Department of Biomaterials
- Fujian Key Laboratory of Materials Genome
- College of Materials
- Xiamen University
- Xiamen 361005
| | - Dongtao Ge
- Department of Biomaterials
- Fujian Key Laboratory of Materials Genome
- College of Materials
- Xiamen University
- Xiamen 361005
| | - Wei Shi
- Department of Biomaterials
- Fujian Key Laboratory of Materials Genome
- College of Materials
- Xiamen University
- Xiamen 361005
| | - Yanan Sun
- Department of Biomaterials
- Fujian Key Laboratory of Materials Genome
- College of Materials
- Xiamen University
- Xiamen 361005
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Identification and molecular characterization of the homogentisate pathway responsible for pyomelanin production, the major melanin constituents in Aeromonas media WS. PLoS One 2015; 10:e0120923. [PMID: 25793756 PMCID: PMC4368426 DOI: 10.1371/journal.pone.0120923] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2014] [Accepted: 01/27/2015] [Indexed: 11/19/2022] Open
Abstract
The pigmentation of many Aeromonas species has been thought to be due to the production of a L-DOPA (L-3,4-dihydroxyphenylalanine) based melanin. However, in this study we found that although L-DOPA synthesis occurs in the high-melanin-yielding Aeromonas media strain WS, it plays a minor, if any, role in pigmentation. Instead, the pigmentation of A. media strain WS is due to the production of pyomelanin through HGA (homogentisate). Gene products of phhA (encodes phenylalanine hydroxylase), tyrB and aspC (both encode aromatic amino acid aminotransferase), and hppD (encodes 4-hydroxyphenylpyruvate dioxygenase) constitute a linear pathway of converting phenylalanine to HGA and disruption of any one of these genes impairs or blocks pigmentation of A. media strain WS. This HGA biosynthesis pathway is widely distributed in Aeromonas, but HGA is only detectable in the cultures of pigmented Aeromonas species. Heterologous expression of HppD from both pigmented and non-pigmented Aeromonas species in E. coli leads to the production of pyomelanin and thus pigmentation, suggesting that most Aeromonas species have the critical enzymes to produce pyomelanin through HGA. Taken together, we have identified a widely conserved biosynthesis pathway of HGA based pyomelanin in Aeromonas that may be responsible for pigmentation of many Aeromonas species.
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Liu YC, Tu SY, Lin HY. Evaluation of the Practicality of Melanin as a Photodynamic-Inactivation Photosensitizer by Its Nanonization. J PHOTOPOLYM SCI TEC 2015. [DOI: 10.2494/photopolymer.28.739] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Yi-Cheng Liu
- Graduate Institute of Photonics and Optoelectronics, and Department of Electrical Engineering, National Taiwan University
- Institute of Atomic and Molecular Sciences, Academia Sinica
| | - Shih-Yu Tu
- Graduate Institute of Photonics and Optoelectronics, and Department of Electrical Engineering, National Taiwan University
| | - Hoang-Yan Lin
- Graduate Institute of Photonics and Optoelectronics, and Department of Electrical Engineering, National Taiwan University
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Chikvaidze EN, Partskhaladze TM, Gogoladze TV. Electron spin resonance (ESR/EPR) of free radicals observed in human red hair: a new, simple empirical method of determination of pheomelanin/eumelanin ratio in hair. MAGNETIC RESONANCE IN CHEMISTRY : MRC 2014; 52:377-382. [PMID: 24757073 DOI: 10.1002/mrc.4075] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/12/2012] [Revised: 03/19/2014] [Accepted: 03/24/2014] [Indexed: 06/03/2023]
Abstract
The definition of the concentration of pheomelanin in the skin is an issue of great interest because in the case of being influenced by UV radiation, it manifests itself as a prooxidant, causing various skin disorders including melanoma that might help to explain the relatively high incidence of skin cancer among individuals with red hair. The ESR spectra of red hair samples were investigated. It was found that at low microwave power, they are characterized by two types of spectra. Red hair ESR signals result from a superposition of two spectral shapes, a singlet spectrum as a result of the existence of eumelanin and a triplet spectrum as a result of the existence of pheomelanin. At high microwave power, only triplet spectra shape was detected, caused by saturation of the eumelanin singlet. Using different concentration ratios of black to red hair, we measured ESR spectra and plotted the ratio values in each sample against a measured 'g-factor' (experimental). We found that there is a linear relationship between these two parameters. So, it is evident that using these results, the concentration ratio of pheomelanin to eumelanin in a sample of hair can be easily determined by an almost noninvasive method. This can be considered a potential advantage for many practical activities compared with other invasive methods. The concentration dependence curve of pheomelanin (µg/mg) on gexp-factor in an ESR spectrum of hair has been designed, which allows the determination of the amount of pheomelanin in hair of any color.
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Affiliation(s)
- Eduard N Chikvaidze
- Department of Biophysics, Faculty of Exact and Natural Sciences, I. Javakhishvili Tbilisi State University, 3 Chavchavadze Ave., Box 0128, Tbilisi, Georgia
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Napolitano A, Panzella L, Monfrecola G, d'Ischia M. Pheomelanin-induced oxidative stress: bright and dark chemistry bridging red hair phenotype and melanoma. Pigment Cell Melanoma Res 2014; 27:721-33. [PMID: 24814217 DOI: 10.1111/pcmr.12262] [Citation(s) in RCA: 100] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2014] [Accepted: 05/08/2014] [Indexed: 01/20/2023]
Abstract
The complex interplay of genetic and epigenetic factors linking sun exposure to melanoma in the red hair phenotype hinges on the peculiar physical and chemical properties of pheomelanins and the underlying biosynthetic pathway, which is switched on by the effects of inactivating polymorphisms in the melanocortin 1 receptor gene. In addition to the long recognized UV-dependent pathways of toxicity and cell damage, a UV-independent pro-oxidant state induced by pheomelanin within the genetically determined background of the red hair phenotype has recently been disclosed. This review provides a detailed discussion of the possible UV-dependent and UV-independent chemical mechanisms underlying pheomelanin-mediated oxidative stress, with special reference to the oxygen-dependent depletion of glutathione and other cell antioxidants. The new concept of pheomelanin as a 'living' polymer and biocatalyst that may grow by exposure to monomer building blocks and may trigger autooxidative processes is also discussed. As a corollary, treatment of inflammatory skin diseases in RHP patients is briefly commented. Finally, possible concerted strategies for melanoma prevention in the red hair phenotype are proposed.
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32
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Beltrán-García MJ, Prado FM, Oliveira MS, Ortiz-Mendoza D, Scalfo AC, Pessoa A, Medeiros MHG, White JF, Di Mascio P. Singlet molecular oxygen generation by light-activated DHN-melanin of the fungal pathogen Mycosphaerella fijiensis in black Sigatoka disease of bananas. PLoS One 2014; 9:e91616. [PMID: 24646830 PMCID: PMC3960117 DOI: 10.1371/journal.pone.0091616] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2013] [Accepted: 02/13/2014] [Indexed: 02/03/2023] Open
Abstract
In pathogenic fungi, melanin contributes to virulence, allowing tissue invasion and inactivation of the plant defence system, but has never been implicated as a factor for host cell death, or as a light-activated phytotoxin. Our research shows that melanin synthesized by the fungal banana pathogen Mycosphaerella fijiensis acts as a virulence factor through the photogeneration of singlet molecular oxygen O2 (1Δg). Using analytical tools, including elemental analysis, ultraviolet/infrared absorption spectrophometry and MALDI-TOF mass spectrometry analysis, we characterized both pigment content in mycelia and secreted to the culture media as 1,8-dihydroxynaphthalene (DHN)-melanin type compound. This is sole melanin-type in M. fijiensis. Isolated melanins irradiated with a Nd:YAG laser at 532 nm produced monomol light emission at 1270 nm, confirming generation of O2 (1Δg), a highly reactive oxygen specie (ROS) that causes cellular death by reacting with all cellular macromolecules. Intermediary polyketides accumulated in culture media by using tricyclazole and pyroquilon (two inhibitors of DHN-melanin synthesis) were identified by ESI-HPLC-MS/MS. Additionally, irradiation at 532 nm of that mixture of compounds and whole melanized mycelium also generated O2 (1Δg). A pigmented-strain generated more O2 (1Δg) than a strain with low melanin content. Banana leaves of cultivar Cavendish, naturally infected with different stages of black Sigatoka disease, were collected from field. Direct staining of the naturally infected leaf tissues showed the presence of melanin that was positively correlated to the disease stage. We also found hydrogen peroxide (H2O2) but we cannot distinguish the source. Our results suggest that O2 (1Δg) photogenerated by DHN-melanin may be involved in the destructive effects of Mycosphaerella fijiensis on banana leaf tissues. Further studies are needed to fully evaluate contributions of melanin-mediated ROS to microbial pathogenesis.
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Affiliation(s)
- Miguel J. Beltrán-García
- Departamento de Química-ICET, Universidad Autónoma de Guadalajara, Zapopan Jalisco, Mexico
- Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, São Paulo, SP, Brazil
| | - Fernanda M. Prado
- Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, São Paulo, SP, Brazil
| | - Marilene S. Oliveira
- Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, São Paulo, SP, Brazil
| | - David Ortiz-Mendoza
- Departamento de Química-ICET, Universidad Autónoma de Guadalajara, Zapopan Jalisco, Mexico
- Instituto de Ingeniería, Universidad Autónoma de Baja California, Mexicali Baja California, Mexico
| | - Alexsandra C. Scalfo
- Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, São Paulo, SP, Brazil
| | - Adalberto Pessoa
- Faculdade de Ciências Farmacêuticas, Departamento de Tecnologia Bioquímico-Farmacêutica, Universidade de São Paulo, São Paulo, Brazil
| | - Marisa H. G. Medeiros
- Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, São Paulo, SP, Brazil
| | - James F. White
- Department of Plant Biology and Pathology, School of Environmental and Biological Sciences, Rutgers University, New Brunswick, New Jersey, United States of America
| | - Paolo Di Mascio
- Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, São Paulo, SP, Brazil
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33
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Seiberg M. Age-induced hair greying - the multiple effects of oxidative stress. Int J Cosmet Sci 2013; 35:532-8. [PMID: 24033376 DOI: 10.1111/ics.12090] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2013] [Accepted: 08/20/2013] [Indexed: 01/14/2023]
Abstract
An obvious sign of ageing is hair greying, or the loss of pigment production and deposition within the hair shafts. Numerous mechanisms, acting at different levels and follicular locations, contribute to hair greying, ranging from melanocyte stem cells defects to follicular melanocyte death. One key issue that is in common to these processes is oxidative damage. At the hair follicle stem cells niche, oxidative stress, accelerated by B-cell lymphoma 2 gene (BCL-2) depletion, leads to selective apoptosis and diminution of melanocyte stem cells, reducing the repopulation of newly formed anagen follicles. Melanotic bulbar melanocytes express high levels of BCL-2 to enable survival from melanogenesis- and ultraviolet A (UVA)-induced reactive oxygen species (ROS) attacks. With ageing, the bulbar melanocyte expression of anti-oxidant proteins such as BCL-2, and possibly TRP-2, is reduced, and the dedicated enzymatic anti-oxidant defence system throughout the follicle weakens, resulting in enhanced oxidative stress. A marked reduction in catalase expression and activity results in millimolar accumulation of hydrogen peroxide, contributing to bulbar melanocyte malfunction and death. Interestingly, amelanotic melanocytes at the outer root sheath (ORS) are somewhat less affected by these processes and survive for longer time even within the white, ageing hair follicles. Better understanding of the overtime susceptibility of melanocytes to oxidative stress at the different follicular locations might yield clues to possible therapies for the prevention and reversal of hair greying.
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Affiliation(s)
- M Seiberg
- Seiberg Consulting, LLC, Princeton, NJ, USA
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Napolitano A, Panzella L, Leone L, d’Ischia M. Red hair benzothiazines and benzothiazoles: mutation-inspired chemistry in the quest for functionality. Acc Chem Res 2013; 46:519-28. [PMID: 23270471 DOI: 10.1021/ar300219u] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Nature provides a primary source of leads for the design of π-conjugated organic chromophores and other functional molecular systems useful for molecular recognition, light harvesting, photoconversion, and other technological applications. In this Account, we draw attention to a unique group of naturally occurring heterocyclic compounds, the 2H-1,4-benzothiazines and related benzothiazole derivatives. Derived from tyrosine and cysteine, these molecules arise from a mutation-induced deviation of the melanin pathway to provide the core structure of the red human hair pigments pheomelanins. Since the elucidation of the biosynthetic pathway of pheomelanins in the 1960s, researchers have focused on 1,4-benzothiazines and red hair pigments. Not only do these molecules have interesting photochemical and molecular recognition properties, they also have compelling biomedical significance. Numerous studies have linked higher levels of pheomelanins and mutations in the pathways that produce these pigments in individuals with red hair and fair skin with an increased sensitivity to UV light and a higher susceptibility to melanoma and other skin cancers. Prompted by new data about the structure and photochemistry of the bibenzothiazine system, this Account highlights the chemistry of benzothiazines in red-haired individuals as a novel source of inspiration in the quest for innovative scaffolds and biomimetic functional systems. Model studies have gradually shed light on a number of remarkable physical and chemical properties of benzothiazine-based systems. Bibenzothiazine is a robust visible chromophore that combines photochromism and acidichromism. Benzothiazine-based polymers (synthetic pheomelanins) show remarkable photochemical, paramagnetic, and redox cycling properties. Biomimetic or synthetic manipulations of the benzothiazine systems, through decarboxylation pathways controlled by metal ions or unusually facile ring-contraction processes, can produce a diverse set of molecular scaffolds.
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Affiliation(s)
- Alessandra Napolitano
- Department of Chemical Sciences, University of Naples Federico II, Via Cinthia 4, I-80126 Naples, Italy
| | - Lucia Panzella
- Department of Chemical Sciences, University of Naples Federico II, Via Cinthia 4, I-80126 Naples, Italy
| | - Loredana Leone
- Department of Chemical Sciences, University of Naples Federico II, Via Cinthia 4, I-80126 Naples, Italy
| | - Marco d’Ischia
- Department of Chemical Sciences, University of Naples Federico II, Via Cinthia 4, I-80126 Naples, Italy
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35
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Sabido A, Martínez LM, de Anda R, Martínez A, Bolívar F, Gosset G. A novel plasmid vector designed for chromosomal gene integration and expression: use for developing a genetically stable Escherichia coli melanin production strain. Plasmid 2012; 69:16-23. [PMID: 22884755 DOI: 10.1016/j.plasmid.2012.04.005] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2012] [Revised: 04/12/2012] [Accepted: 04/18/2012] [Indexed: 11/16/2022]
Abstract
Recombinant Escherichia coli strains for the production of valuable products are usually generated by transformation with plasmid expression vectors. However, in spite of their usefulness, common problems associated with plasmid use include segregrational and structural instability as well as undesired copy-number effects. A viable alternative to plasmid use is chromosomal gene integration. With the purpose of facilitating the process of stable strain generation, a novel chromosomal integration vector was developed and tested. We describe the construction and use of novel expression vector pLoxGentrc that contains the strong trc promoter (P(trc)), a multiple cloning site, the T1 and T2 rrnB terminator sequences, the lacI(q) gene and the aacC1 gene conferring gentamicin resistance flanked by two loxP sites. As a demonstration of utility, melanin-producing strains of E. coli were generated employing this vector. Melanin is a polymer synthesized by the enzyme tyrosinase using l-tyrosine as substrate. The melA gene encoding a tyrosinase from Rhizobium etli was ligated to pLoxGentrc to generate pLoxGentrcmelA. This plasmid was transformed into E. coli W3110 to generate a melanin-producing strain. A region from this plasmid including P(trc)melA, T1 and T2 rrnB and the aacC1 gene was amplified by PCR employing primers with 45 b regions of homology to the lacZ gene. The PCR product was electroporated into strain W3110 that expressed the λ-Red enzymes. From this experiment, strain W3110P(tr)(c)melA, was obtained having the melA gene inserted in the lacZ locus. Fermentor cultures with strain W3110/pLoxGentrcmelA grown in the presence and absence of gentamicin as well as W3110P(tr)(c)melA without antibiotic revealed that the latter displays high genetic stability as well as the highest melanin titer. Vector pLoxGentrc should be useful during strain generation processes, enabling direct comparison of plasmid and chromosome-based production systems.
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Affiliation(s)
- Andrea Sabido
- Departamento de Ingeniería Celular y Biocatálisis, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Apdo. Postal 510-3, Cuernavaca, Morelos 62210, Mexico
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36
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Suzukawa AA, Vieira A, Winnischofer SMB, Scalfo AC, Di Mascio P, Ferreira AMDC, Ravanat JL, Martins DDL, Rocha MEM, Martinez GR. Novel properties of melanins include promotion of DNA strand breaks, impairment of repair, and reduced ability to damage DNA after quenching of singlet oxygen. Free Radic Biol Med 2012; 52:1945-53. [PMID: 22401857 DOI: 10.1016/j.freeradbiomed.2012.02.039] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/31/2011] [Revised: 02/17/2012] [Accepted: 02/24/2012] [Indexed: 01/22/2023]
Abstract
Melanins have been associated with the development of melanoma and its resistance to photodynamic therapy (PDT). Singlet molecular oxygen ((1)O(2)), which is produced by ultraviolet A solar radiation and the PDT system, is also involved. Here, we investigated the effects that these factors have on DNA damage and repair. Our results show that both types of melanin (eumelanin and pheomelanin) lead to DNA breakage in the absence of light irradiation and that eumelanin is more harmful than pheomelanin. Interestingly, melanins were found to bind to the minor grooves of DNA, guaranteeing close proximity to DNA and potentially causing the observed high levels of strand breaks. We also show that the interaction of melanins with DNA can impair the access of repair enzymes to lesions, contributing to the perpetuation of DNA damage. Moreover, we found that after melanins interact with (1)O(2), they exhibit a lower ability to induce DNA breakage; we propose that these effects are due to modifications of their structure. Together, our data highlight the different modes of action of the two types of melanin. Our results may have profound implications for cellular redox homeostasis, under conditions of induced melanin synthesis and irradiation with solar light. These results may also be applied to the development of protocols to sensitize melanoma cells to PDT.
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Affiliation(s)
- Andréia Akemi Suzukawa
- Departamento de Bioquímica e Biologia Molecular, Universidade Federal do Paraná, 81.531-980 Curitiba, PR, Brazil
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37
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Page S, Chandhoke V, Baranova A. Melanin and melanogenesis in adipose tissue: possible mechanisms for abating oxidative stress and inflammation? Obes Rev 2011; 12:e21-31. [PMID: 20576005 DOI: 10.1111/j.1467-789x.2010.00773.x] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Obesity has become a worldwide epidemic and can lead to multiple chronic diseases. Adipose tissue is increasingly thought to play an active role in obesity-related pathologies such as insulin resistance and non-alcoholic fatty liver disease. Obesity has been strongly associated with systemic inflammation and, to a lesser degree, with oxidative stress, although the causal relationships among these factors are unclear. A recent study demonstrating an expression of the components of the melanogenic pathway and the presence of melanin in visceral adipose has raised questions regarding the possible role of melanogenesis in adipose tissue. As this study also found larger amounts of melanin in the adipose tissue of obese patients relative to lean ones, we hypothesize that melanin, a pigment known for its antioxidant and anti-inflammatory properties, may scavenge reactive oxygen species and abate oxidative stress and inflammation in adipose tissue. This review considers the evidence to support such a hypothesis, and speculates on the role of melanin within adipocytes. Furthermore, we consider whether the α-melanocyte-stimulating hormone or its synthetic analogues could be used to stimulate melanin production in adipocytes, should the hypothesis be supported in future experiments.
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Affiliation(s)
- S Page
- Department of Molecular and Microbiology, College of Science, George Mason University, Fairfax Center for Liver Diseases, Inova Fairfax Hospital, Falls Church, VA, USA
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38
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Wakamatsu K, Ohtara K, Ito S. Chemical analysis of late stages of pheomelanogenesis: conversion of dihydrobenzothiazine to a benzothiazole structure. Pigment Cell Melanoma Res 2009; 22:474-86. [PMID: 19493317 DOI: 10.1111/j.1755-148x.2009.00580.x] [Citation(s) in RCA: 76] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
Pheomelanogenesis is a complex pathway that starts with the oxidation of tyrosine (or DOPA, 3,4-dihydroxyphenylalanine) by tyrosinase in the presence of cysteine, which results in the production of 5-S-cysteinyldopa and its isomers. Beyond that step, relatively little has been clarified except for a possible intermediate produced, dihydro-1,4-benzothiazine-3-carboxylic acid (DHBTCA). We therefore carried out a detailed study on the course of pheomelanogenesis using DOPA and cysteine and the physiological enzyme tyrosinase. To elucidate the later stages of pheomelanogenesis, chemical degradative methods of reductive hydrolysis with hydroiodic acid and alkaline peroxide oxidation were applied. The results show that: (1) DHBTCA accumulates after the disappearance of the cysteinyldopa isomers, (2) DHBTCA is then oxidized by a redox exchange with dopaquinone to form ortho-quinonimine, which leads to the production of pheomelanin with a benzothiazine moiety, and (3) the benzothiazine moiety gradually degrades to form a benzothiazole moiety. This latter process is consistent with the much higher ratio of benzothiazole-derived units in human red hair than in mouse yellow hair. These findings may be relevant to the (photo)toxic effects of pheomelanin.
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Affiliation(s)
- Kazumasa Wakamatsu
- Department of Chemistry, Fujita Health University School of Health Sciences, Toyoake, Aichi, Japan
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39
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The effect of melanism and vitamin D synthesis on the incidence of autoimmune disease. ACTA ACUST UNITED AC 2009; 5:99-105. [PMID: 19182816 DOI: 10.1038/ncprheum0989] [Citation(s) in RCA: 97] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2008] [Accepted: 12/03/2008] [Indexed: 02/07/2023]
Abstract
Melanin has several physiological roles in maintaining health, but, notably, it affects the synthesis of vitamin D. Melanin is the primary determinant of the degree of skin pigmentation and protects the body from harmful ultraviolet radiation. Synthesis of 1,25-dihydroxyvitamin D(3) (1,25[OH](2)D(3)) in the skin, however, is dependent on ultraviolet B light. Highly pigmented skin, to the level found in people of African origin, abrogates almost all ultraviolet-induced 1,25(OH)(2)D(3) synthesis. Numerous animal models and clinical studies have underlined the essential role of vitamin D as a modulator of the different processes of the immune system. Evidence indicates that serum concentrations of 1,25(OH)(2)D(3) and the prevalence of autoimmune diseases in a certain population are associated with the latitude at which that population resides. This article explores the relationship between skin pigmentation, vitamin D and the prevalence of autoimmune disease.
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40
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Lei M, Xue CH, Wang YM, Li ZJ, Xue Y, Wang JF. Effect of squid ink melanin-Fe on iron deficiency anemia remission. J Food Sci 2009; 73:H207-11. [PMID: 19019117 DOI: 10.1111/j.1750-3841.2008.00930.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The present study was designed to evaluate the effect of a new iron tonic (squid ink melanin-Fe [SM-Fe]) on remission of iron deficiency anemia (IDA) using a rat model of IDA. The rat IDA model was established with low-iron diet feeding and caudal vein blooding. Then different dosages of SM-Fe were given to the rats once a day by intragastric administration, with FeSO4 and FeCl3 as positive control. The content of Hemoglobin (Hb), red blood cell (RBC), hematocrit (HCT), and mean corpuscular volume (MCV) were analyzed in addition to the contents of serum iron (SI) and intracellular free erythrocyte protoporphyrin (FEP). The content of malondialdehyde (MDA) and the activity of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) in serum was also measured. The results showed that anemia caused by iron deficiency was established as a consequence of the low-iron diets. SM-Fe showed an effective restoration action by returning Hb, RBC, HCT, MCV, SI, and FEP in IDA animals to normal values. An antioxidant effect was also observed that reduced MDA level, enhanced the activities of SOD and GSH-Px in serum, and protected erythrocytes from the injury of reactive oxygen species as a consequence of SM-Fe intake. In comparison with FeSO4 and FeCl3, higher bioavailability of iron and fewer side effects were also observed. In conclusion, SM-Fe remitted iron deficiency anemia symptoms significantly, suggesting that SM-Fe might contribute to improving hemopoietic function in IDA rats and might be exploited as a safe, efficient new iron tonic.
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Affiliation(s)
- M Lei
- College of Food Science and Technology, Ocean Univ. of China, Qingdao 266003, China
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41
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Duong HA, Chua S, Huleatt PB, Chai CLL. Synthesis of Biindolyls via Palladium-Catalyzed Reactions. J Org Chem 2008; 73:9177-80. [DOI: 10.1021/jo801846b] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Hung A. Duong
- Institute of Chemical and Engineering Sciences, Agency for Science, Technology and Research (A*STAR), 1 Pesek Rd, Jurong Island, Singapore 627833
| | - Sheena Chua
- Institute of Chemical and Engineering Sciences, Agency for Science, Technology and Research (A*STAR), 1 Pesek Rd, Jurong Island, Singapore 627833
| | - Paul B. Huleatt
- Institute of Chemical and Engineering Sciences, Agency for Science, Technology and Research (A*STAR), 1 Pesek Rd, Jurong Island, Singapore 627833
| | - Christina L. L. Chai
- Institute of Chemical and Engineering Sciences, Agency for Science, Technology and Research (A*STAR), 1 Pesek Rd, Jurong Island, Singapore 627833
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42
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Abstract
Melanins can be classified into two major groups-insoluble brown to black pigments termed eumelanin and alkali-soluble yellow to reddish-brown pigments termed pheomelanin. Both types of pigment derive from the common precursor dopaquinone (ortho-quinone of 3,4-dihydroxyphenylalanine) which is formed via the oxidation of l-tyrosine by the melanogenic enzyme tyrosinase. Dopaquinone is a highly reactive ortho-quinone that plays pivotal roles in the chemical control of melanogenesis. In the absence of sulfhydryl compounds, dopaquinone undergoes intramolecular cyclization to form cyclodopa, which is then rapidly oxidized by a redox reaction with dopaquinone to give dopachrome (and dopa). Dopachrome then gradually and spontaneously rearranges to form 5,6-dihydroxyindole and to a lesser extent 5,6-dihydroxyindole-2-carboxylic acid, the ratio of which is determined by a distinct melanogenic enzyme termed dopachrome tautomerase (tyrosinase-related protein-2). Oxidation and subsequent polymerization of these dihydroxyindoles leads to the production of eumelanin. However, when cysteine is present, this process gives rise preferentially to the production of cysteinyldopa isomers. Cysteinyldopas are subsequently oxidized through redox reaction with dopaquinone to form cysteinyldopaquinones that eventually lead to the production of pheomelanin. Pulse radiolysis studies of early stages of melanogenesis (involving dopaquinone and cysteine) indicate that mixed melanogenesis proceeds in three distinct stages-the initial production of cysteinyldopas, followed by their oxidation to produce pheomelanin, followed finally by the production of eumelanin. Based on these data, a casing model of mixed melanogenesis is proposed in which a preformed pheomelanic core is covered by a eumelanic surface.
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Affiliation(s)
- Shosuke Ito
- Department of Chemistry, Fujita Health University School of Health Sciences, Aichi, Japan.
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Wakamatsu K, Hu DN, McCormick SA, Ito S. Characterization of melanin in human iridal and choroidal melanocytes from eyes with various colored irides. Pigment Cell Melanoma Res 2008; 21:97-105. [PMID: 18353148 DOI: 10.1111/j.1755-148x.2007.00415.x] [Citation(s) in RCA: 92] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Variance in iris color is related to the incidence of several important ocular diseases, including uveal melanoma and age-related macular degeneration. The purposes of this study were to determine the quantity and the types of melanin in cultured human uveal melanocytes in relation to the iris color. Sixty-one cell cultures of pure uveal melanocytes were isolated from donor eyes with various iris colors. The amount of eumelanin (EM) and pheomelanin (PM) of these cells was measured by chemical degradation and microanalytical high-performance liquid chromatography (HPLC) methods. The total amount of melanin was measured by both microanalytical methods and spectrophotometry. Total melanin content, measured by HPLC and spectrophotometry, correlated well with r = 0.872 (P < 0.0001). The quantity and type of melanin in iridal and choroidal melanocytes showed no significant difference (P > 0.05). When cells became senescent, the levels of EM, PM and total melanin were significantly increased. In both growing and senescent melanocytes, the quantity and type of melanin were closely correlated to the iris color. In cells from eyes with dark-colored irides (dark brown and brown), the amount of EM, the ratio of EM/PM and total melanin were significantly greater than that from eyes with light-colored irides (hazel, green, yellow-brown and blue) (P < 0.0001). The quantity of PM in uveal melanocytes from eyes with light-colored irides was slightly greater than that from dark-colored irides, although not statistically significant (P > 0.05). The present study shows that iris color is determined by both the quantity and the type of melanin in uveal melanocytes. These results suggest a possibility that uveal melanin in eyes with dark-colored irides is eumelanic at the surface and acts as an antioxidant while that in eyes with light-colored irides exposes pheomelanic core and behaves as a pro-oxidant.
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Affiliation(s)
- Kazumasa Wakamatsu
- Department of Chemistry, Fujita Health University School of Health Sciences, Toyoake, Aichi, Japan
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Wang A, Marino AR, Gasyna Z, Gasyna E, Norris J. Photoprotection by porcine eumelanin against singlet oxygen production. Photochem Photobiol 2008; 84:679-82. [PMID: 18422874 DOI: 10.1111/j.1751-1097.2008.00353.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Melanin, a major pigment found in retinal pigment epithelium (RPE) cells, is considered to function in dual roles, one protective and one destructive. By quenching free radical species and reactive oxygen species (ROS) melanin counteracts harmful redox stress. However, melanin is also thought to be capable of creating ROS. In this destructive role, melanin increases redox strain in the cell. This study uses readily available eumelanin extracted from porcine RPE cells as a more authentic model than synthetic melanin to determine specific mechanisms of melanin activity with regard to singlet oxygen in the presence and absence of rose bengal, a singlet-oxygen photosensitizer. Optical detection of singlet-oxygen was determined by monitoring the bleaching of p-nitrosodimethylaniline in the presence of histidine. Production of singlet oxygen in aqueous oxygen-saturated solutions of rose bengal without eumelanin was readily accomplished. In contrast, detection of singlet oxygen in oxygen-saturated solutions of eumelanin without rose bengal failed, consistent with results of others. However, a significant decrease in singlet oxygen production by rose bengal was observed in the presence of eumelanin. After correction for light absorption and chemical bleaching of eumelanin, the results show that eumelanin also provides a photoprotective mode arising from chemistry, that is, not just the physical process of light absorption followed by energy dissipation as heat.
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Affiliation(s)
- Alice Wang
- Department of Chemistry, University of Chicago, Chicago, IL, USA.
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Hu DN, Simon JD, Sarna T. Role of ocular melanin in ophthalmic physiology and pathology. Photochem Photobiol 2008; 84:639-44. [PMID: 18346089 DOI: 10.1111/j.1751-1097.2008.00316.x] [Citation(s) in RCA: 163] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
The mammalian eye consists of several layers of pigmented tissues that contain melanin. The eye is a unique organ for pigment cell research because one can isolate and compare melanosomes from different tissues and embryonic origins. Retinal, iris and ciliary pigment epithelial cells are derived from the neural ectoderm, more specifically from the extremity of the embryonic optical cup, which is also the origin of the retina. In contrast, the pigment-generating cells in the choroid and in the stroma of the iris and ciliary body, uveal melanocytes, are developed from the neural crest, the same origin as the melanocytes in skin and hair. This review examines the potential functions of ocular melanin in the human eye. Following a discussion of the role of melanins in the pigment epithelium and uveal melanocytes, three specific topics are explored in detail-photo-screening protective effects, biophysical and biochemical protective effects, and the biologic and photobiologic effects of the two main classes of melanins (generally found as mixtures in ocular melanosomes)--eumelanin and pheomelanin.
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Affiliation(s)
- Dan-Ning Hu
- Tissue Culture Center, Department of Pathology, The New York Eye and Ear Infirmary and New York Medical College, New York, NY, USA.
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Lagunas-Muñoz VH, Cabrera-Valladares N, Bolívar F, Gosset G, Martínez A. Optimum melanin production using recombinant Escherichia coli. J Appl Microbiol 2007; 101:1002-8. [PMID: 17040223 DOI: 10.1111/j.1365-2672.2006.03013.x] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
AIMS A parametric study was conducted to define optimum conditions to achieve high yields in the conversion of tyrosine to eumelanin (EuMel) using recombinant Escherichia coli. METHODS AND RESULTS Escherichia coli W3110 (pTrcMutmelA) expressing the tyrosinase coding gene from Rhizobium etli and glucose-mineral media were used to transform tyrosine into EuMel. Batch aerobic fermentor cultures were performed to study the effect of temperature, pH and inducer concentration (isopropyl-D-thio-galactopyranoside) on melanin production. Under optimum conditions, 0.1 mmol l(-1) of isopropyl-D-thio-galactopyranoside, temperature of 30 degrees C, and changing pH from 7.0 to 7.5 during the production phase, a 100% conversion of tyrosine into EuMel is obtained. Furthermore, tyrosine feeding allowed us to obtain the highest level (6 g l(-1)) of EuMel produced by recombinant E. coli reported until now. CONCLUSIONS The most important factors affecting melanin formation and hence influencing the rate and efficiency in the conversion of tyrosine into EuMel in this system, are the temperature and pH. SIGNIFICANCE AND IMPACT OF THE STUDY Maximum theoretical yield was obtained using a simple culture process and mineral media to convert tyrosine (a medium value compound) into melanin, a high value compound. The process reported here avoids the use of purified tyrosinase, expensive chemical methods or the cumbersome extraction of this polymer from animal or plant tissues.
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Affiliation(s)
- V H Lagunas-Muñoz
- Departamento de Ingeniería Celular y Biocatálisis, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Morelos, Mexico
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Samokhvalov A, Hong L, Liu Y, Garguilo J, Nemanich RJ, Edwards GS, Simon JD. Oxidation Potentials of Human Eumelanosomes and Pheomelanosomes¶. Photochem Photobiol 2007. [DOI: 10.1111/j.1751-1097.2005.tb01533.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Liu Y, Hong L, Wakamatsu K, Ito S, Adhyaru B, Cheng CY, Bowers CR, Simon JD. Comparison of Structural and Chemical Properties of Black and Red Human Hair Melanosomes¶. Photochem Photobiol 2007. [DOI: 10.1111/j.1751-1097.2005.tb01532.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Qu X, Kirschenbaum LJ, Borish ET. Hydroxyterephthalate as a Fluorescent Probe for Hydroxyl Radicals: Application to Hair Melanin. Photochem Photobiol 2007. [DOI: 10.1562/0031-8655(2000)0710307haafpf2.0.co2] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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50
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Samokhvalov A, Liu Y, Simon JD. Characterization of the Fe(III)-binding Site in Sepia Eumelanin by Resonance Raman Confocal Microspectroscopy¶. Photochem Photobiol 2007. [DOI: 10.1111/j.1751-1097.2004.tb00053.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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