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Wang K, Mao W, Song X, Chen M, Feng W, Peng B, Chen Y. Reactive X (where X = O, N, S, C, Cl, Br, and I) species nanomedicine. Chem Soc Rev 2023; 52:6957-7035. [PMID: 37743750 DOI: 10.1039/d2cs00435f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/26/2023]
Abstract
Reactive oxygen, nitrogen, sulfur, carbonyl, chlorine, bromine, and iodine species (RXS, where X = O, N, S, C, Cl, Br, and I) have important roles in various normal physiological processes and act as essential regulators of cell metabolism; their inherent biological activities govern cell signaling, immune balance, and tissue homeostasis. However, an imbalance between RXS production and consumption will induce the occurrence and development of various diseases. Due to the considerable progress of nanomedicine, a variety of nanosystems that can regulate RXS has been rationally designed and engineered for restoring RXS balance to halt the pathological processes of different diseases. The invention of radical-regulating nanomaterials creates the possibility of intriguing projects for disease treatment and promotes advances in nanomedicine. In this comprehensive review, we summarize, discuss, and highlight very-recent advances in RXS-based nanomedicine for versatile disease treatments. This review particularly focuses on the types and pathological effects of these reactive species and explores the biological effects of RXS-based nanomaterials, accompanied by a discussion and the outlook of the challenges faced and future clinical translations of RXS nanomedicines.
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Affiliation(s)
- Keyi Wang
- Department of Urology, Shanghai Tenth People's Hospital, School of Medicine, Tongji University, Shanghai, 200072, P. R. China.
| | - Weipu Mao
- Department of Urology, Affiliated Zhongda Hospital of Southeast University, Nanjing, 210009, P. R. China
| | - Xinran Song
- Materdicine Lab, School of Life Sciences, Shanghai University, Shanghai, 200444, P. R. China.
| | - Ming Chen
- Department of Urology, Affiliated Zhongda Hospital of Southeast University, Nanjing, 210009, P. R. China
| | - Wei Feng
- Materdicine Lab, School of Life Sciences, Shanghai University, Shanghai, 200444, P. R. China.
| | - Bo Peng
- Department of Urology, Shanghai Tenth People's Hospital, School of Medicine, Tongji University, Shanghai, 200072, P. R. China.
| | - Yu Chen
- Materdicine Lab, School of Life Sciences, Shanghai University, Shanghai, 200444, P. R. China.
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Structural Investigation of DHICA Eumelanin Using Density Functional Theory and Classical Molecular Dynamics Simulations. MOLECULES (BASEL, SWITZERLAND) 2022; 27:molecules27238417. [PMID: 36500509 PMCID: PMC9738096 DOI: 10.3390/molecules27238417] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/28/2022] [Revised: 11/21/2022] [Accepted: 11/22/2022] [Indexed: 12/05/2022]
Abstract
Eumelanin is an important pigment, for example, in skin, hair, eyes, and the inner ear. It is a highly heterogeneous polymer with 5,6-dihydroxyindole-2-carboxylic acid (DHICA) and 5,6-dihydroxyindole (DHI) building blocks, of which DHICA is reported as the more abundant in natural eumelanin. The DHICA-eumelanin protomolecule consists of three building blocks, indole-2-carboxylic acid-5,6-quinone (ICAQ), DHICA and pyrrole-2,3,5-tricarboxylic acid (PTCA). Here, we focus on the self-assembly of DHICA-eumelanin using multi-microsecond molecular dynamics (MD) simulations at various concentrations in aqueous solutions. The molecule was first parameterized using density functional theory (DFT) calculations. Three types of systems were studied: (1) uncharged DHICA-eumelanin, (2) charged DHICA-eumelanin corresponding to physiological pH, and (3) a binary mixture of both of the above protomolecules. In the case of uncharged DHICA-eumelanin, spontaneous aggregation occurred and water molecules were present inside the aggregates. In the systems corresponding to physiological pH, all the carboxyl groups are negatively charged and the DHICA-eumelanin model has a net charge of -4. The effect of K+ ions as counterions was investigated. The results show high probability of binding to the deprotonated oxygens of the carboxylate anions in the PTCA moiety. Furthermore, the K+ counterions increased the solubility of DHICA-eumelanin in its charged form. A possible explanation is that the charged protomolecules favor binding to the K+ ions rather than aggregating and binding to other protomolecules. The binary mixtures show aggregation of uncharged DHICA-eumelanins; unlike the charged systems with no aggregation, a few charged DHICA-eumelanins are present on the surface of the uncharged aggregation, binding to the K+ ions.
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Argenziano R, Della Greca M, Panzella L, Napolitano A. A Straightforward Access to New Amides of the Melanin Precursor 5,6-Dihydroxyindole-2-carboxylic Acid and Characterization of the Properties of the Pigments Thereof. Molecules 2022; 27:4816. [PMID: 35956765 PMCID: PMC9369804 DOI: 10.3390/molecules27154816] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2022] [Revised: 07/18/2022] [Accepted: 07/26/2022] [Indexed: 11/17/2022] Open
Abstract
We report herein an optimized procedure for preparation of carboxamides of 5,6-dihydroxyindole-2-carboxylic acid (DHICA), the main biosynthetic precursor of the skin photoprotective agents melanins, to get access to pigments with more favorable solubility properties with respect to the natural ones. The developed procedure was based on the use of a coupling agent (HATU/DIPEA) and required protection of the catechol function by easily removable acetyl groups. The O-acetylated compounds could be safely stored and taken to the reactive o-diphenol form just before use. Satisfactorily high yields (>85%) were obtained for all amides. The oxidative polymerization of the synthesized amides carried out in air in aqueous buffer at pH 9 afforded melanin-like pigmented materials that showed chromophores resembling those of DHICA-derived pigments, with a good covering of the UVA and the visible region, and additionally exhibited a good solubility in alcoholic solvents, a feature of great interest for the exploitation of these materials as ingredients of dermocosmetic formulations.
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Affiliation(s)
| | | | | | - Alessandra Napolitano
- Department of Chemical Sciences, University of Naples “Federico II”, Via Cintia 21, I-80126 Naples, Italy; (R.A.); (M.D.G.); (L.P.)
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A Melanin-Related Phenolic Polymer with Potent Photoprotective and Antioxidant Activities for Dermo-Cosmetic Applications. Antioxidants (Basel) 2020; 9:antiox9040270. [PMID: 32218123 PMCID: PMC7222206 DOI: 10.3390/antiox9040270] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2020] [Revised: 03/16/2020] [Accepted: 03/23/2020] [Indexed: 12/11/2022] Open
Abstract
Eumelanins, the dark variant of skin pigments, are endowed with a remarkable antioxidant activity and well-recognized photoprotective properties that have been ascribed to pigment components derived from the biosynthetic precursor 5,6-dihydroxyindole-2-carboxylic acid (DHICA). Herein, we report the protective effect of a polymer obtained starting from the methyl ester of DHICA (MeDHICA-melanin) against Ultraviolet A (UVA)-induced oxidative stress in immortalized human keratinocytes (HaCaT). MeDHICA-melanin was prepared by aerial oxidation of MeDHICA. At concentrations as low as 10 µg/mL, MeDHICA-melanin prevented reactive oxygen species accumulation and partially reduced glutathione oxidation in UVA-irradiated keratinocytes. Western blot experiments revealed that the polymer is able to induce the translocation of nuclear factor erythroid 2–related factor 2 (Nrf-2) to the nucleus with the activation of the transcription of antioxidant enzymes, such as heme-oxygenase 1. Spectrophotometric and HPLC analysis of cell lysate allowed to conclude that a significant fraction (ca. 7%), consisting mainly of the 4,4′-dimer of MeDHICA (ca. 2 μM), was internalized in the cells. Overall these data point to the potential use of MeDHICA-melanin as an antioxidant for the treatment of skin damage, photoaging and skin cancers.
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Gelatin-Based Hydrogels for the Controlled Release of 5,6-Dihydroxyindole-2-Carboxylic Acid, a Melanin-Related Metabolite with Potent Antioxidant Activity. Antioxidants (Basel) 2020; 9:antiox9030245. [PMID: 32197438 PMCID: PMC7139803 DOI: 10.3390/antiox9030245] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2020] [Revised: 03/13/2020] [Accepted: 03/16/2020] [Indexed: 02/07/2023] Open
Abstract
The ability of gelatin-based hydrogels of incorporating and releasing under controlled conditions 5,6-dihydroxyindole-2-carboxylic acid (DHICA), a melanin-related metabolite endowed with marked antioxidant properties was investigated. The methyl ester of DHICA, MeDHICA, was also tested in view of its higher stability, and different solubility profile. Three types of gelatin-based hydrogels were prepared: pristine porcine skin type A gelatin (HGel-A), a pristine gelatin cross-linked by amide coupling of lysines and glutamic/aspartic acids (HGel-B), and a gelatin/chitosan blend (HGel-C). HGel-B and HGel-C differed in the swelling behavior, showed satisfactorily high mechanical strength at physiological temperatures and well-defined morphology. The extent of incorporation into all the gelatins tested using a 10% w/w indole to gelatin ratio was very satisfactory ranging from 60 to 90% for either indoles. The kinetics of indole release under conditions of physiological relevance was evaluated up to 72 h. The highest values were obtained with HGel-B and HGel-C for MeDHICA (90% after 6 h), and an appreciable release was observed for DHICA reaching 30% and 40% at 6 h for HGel-B and HGel-C, respectively. At 72 h, DHICA and MeDHICA were released at around 30% from HGel-A at pH 7.4, with an increase up to 40% at pH 5.5 in the case of DHICA. DHICA incorporated into HGel-B proved fairly stable over 6 h whereas the free compound at the same concentration was almost completely oxidized. The antioxidant power of the indole loaded gelatins was monitored by chemical assays and proved unaltered even after prolonged storage in air, suggesting that the materials could be prepared in advance with respect to their use without alteration of their efficacy.
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Kim E, Panzella L, Napolitano A, Payne GF. Redox Activities of Melanins Investigated by Electrochemical Reverse Engineering: Implications for their Roles in Oxidative Stress. J Invest Dermatol 2020; 140:537-543. [DOI: 10.1016/j.jid.2019.09.010] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2019] [Revised: 09/05/2019] [Accepted: 09/25/2019] [Indexed: 12/14/2022]
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Natural and Bioinspired Phenolic Compounds as Tyrosinase Inhibitors for the Treatment of Skin Hyperpigmentation: Recent Advances. COSMETICS 2019. [DOI: 10.3390/cosmetics6040057] [Citation(s) in RCA: 81] [Impact Index Per Article: 16.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
One of the most common approaches for control of skin pigmentation involves the inhibition of tyrosinase, a copper-containing enzyme which catalyzes the key steps of melanogenesis. This review focuses on the tyrosinase inhibition properties of a series of natural and synthetic, bioinspired phenolic compounds that have appeared in the literature in the last five years. Both mushroom and human tyrosinase inhibitors have been considered. Among the first class, flavonoids, in particular chalcones, occupy a prominent role as natural inhibitors, followed by hydroxystilbenes (mainly resveratrol derivatives). A series of more complex phenolic compounds from a variety of sources, first of all belonging to the Moraceae family, have also been described as potent tyrosinase inhibitors. As to the synthetic compounds, hydroxycinnamic acids and chalcones again appear as the most exploited scaffolds. Several inhibition mechanisms have been reported for the described inhibitors, pointing to copper chelating and/or hydrophobic moieties as key structural requirements to achieve good inhibition properties. Emerging trends in the search for novel skin depigmenting agents, including the development of assays that could distinguish between inhibitors and potentially toxic substrates of the enzyme as well as of formulations aimed at improving the bioavailability and hence the effectiveness of well-known inhibitors, have also been addressed.
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8
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Panzella L, Ebato A, Napolitano A, Koike K. The Late Stages of Melanogenesis: Exploring the Chemical Facets and the Application Opportunities. Int J Mol Sci 2018; 19:E1753. [PMID: 29899264 PMCID: PMC6032422 DOI: 10.3390/ijms19061753] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2018] [Revised: 06/08/2018] [Accepted: 06/08/2018] [Indexed: 11/16/2022] Open
Abstract
In the last decade, the late stages of melanin biosynthesis involving the oxidative polymerization of 5,6-dihydroxyindole (DHI) and 5,6-dihydroxyindole-2-carboxylic acid (DHICA) have been extensively investigated. Most of the information derived from a biomimetic approach in which the oxidation of melanogenic indoles was carried out under conditions mimicking those occurring in the biological environment. Characterization of the early oligomers allowed for drawing a structural picture of DHI and DHICA melanins, providing also an interpretative basis for the different properties exhibited by these pigments, e.g., the chromophore and the antioxidant ability. The improved knowledge has opened new perspectives toward the exploitation of the unique chemistry of melanins and its precursors in cosmetic and health care applications. A noticeable example is the development of an innovative hair dyeing system that is based on the marked ease of DHI to give rise to black melanin on air oxidation under slightly alkaline conditions. The advantage of this method for a step-wise coverage of gray hair with a natural shade pigmentation on repeated treatment with a DHI-based formulation with respect to traditional dyes is presented. A variant of DHICA melanin combining solubility in water-miscible organic solvents, an intense chromophore in the UltraViolet-A UV-A region, and a marked antioxidant potency was evaluated as an ingredient for cosmetic formulations.
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Affiliation(s)
- Lucia Panzella
- Department of Chemical Sciences, University of Naples "Federico II", I-80126 Naples, Italy.
| | - Atsuko Ebato
- Hair Care Products Research Laboratories, Kao Corporation, Tokyo 131-8501, Japan.
| | - Alessandra Napolitano
- Department of Chemical Sciences, University of Naples "Federico II", I-80126 Naples, Italy.
| | - Kenzo Koike
- Hair Care Products Research Laboratories, Kao Corporation, Tokyo 131-8501, Japan.
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Micillo R, Iacomino M, Perfetti M, Panzella L, Koike K, D'Errico G, d'Ischia M, Napolitano A. Unexpected impact of esterification on the antioxidant activity and (photo)stability of a eumelanin from 5,6-dihydroxyindole-2-carboxylic acid. Pigment Cell Melanoma Res 2018; 31:475-483. [DOI: 10.1111/pcmr.12689] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2017] [Accepted: 01/03/2018] [Indexed: 11/29/2022]
Affiliation(s)
- Raffaella Micillo
- Department of Chemical Sciences; University of Naples “Federico II”; Naples Italy
| | - Mariagrazia Iacomino
- Department of Chemical Sciences; University of Naples “Federico II”; Naples Italy
| | - Marco Perfetti
- Department of Chemical Sciences; University of Naples “Federico II”; Naples Italy
| | - Lucia Panzella
- Department of Chemical Sciences; University of Naples “Federico II”; Naples Italy
| | - Kenzo Koike
- Hair Care Products Research Laboratories; Kao Corporation; Sumida, Tokyo Japan
| | - Gerardino D'Errico
- Department of Chemical Sciences; University of Naples “Federico II”; Naples Italy
| | - Marco d'Ischia
- Department of Chemical Sciences; University of Naples “Federico II”; Naples Italy
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10
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Büngeler A, Hämisch B, Strube OI. The Supramolecular Buildup of Eumelanin: Structures, Mechanisms, Controllability. Int J Mol Sci 2017; 18:E1901. [PMID: 28878140 PMCID: PMC5618550 DOI: 10.3390/ijms18091901] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2017] [Revised: 08/29/2017] [Accepted: 08/29/2017] [Indexed: 01/07/2023] Open
Abstract
Research on the supramolecular buildup of eumelanin has gained high momentum in the last years. Several new aspects regarding the involved structures and mechanisms have been established, which has led to a better understanding of the entire process. This review intends to provide a clearly laid-out summary of previous and new findings regarding structures, mechanisms, and controllability. With respect to materials applications, the aspect of controllability is of supreme importance. A focus of this review is therefore set on a novel method with high potential for specific synthesis of various, isolated particle morphologies. Finally, open questions and possibilities for their elucidation are discussed.
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Affiliation(s)
- Anne Büngeler
- Biobased and Bioinspired Materials, Department of Chemistry, Paderborn University, 33098 Paderborn, Germany.
| | - Benjamin Hämisch
- Department of Physical Chemistry, Paderborn University, 33098 Paderborn, Germany.
| | - Oliver I Strube
- Biobased and Bioinspired Materials, Department of Chemistry, Paderborn University, 33098 Paderborn, Germany.
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"Fifty Shades" of Black and Red or How Carboxyl Groups Fine Tune Eumelanin and Pheomelanin Properties. Int J Mol Sci 2016; 17:ijms17050746. [PMID: 27196900 PMCID: PMC4881568 DOI: 10.3390/ijms17050746] [Citation(s) in RCA: 80] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2016] [Revised: 05/02/2016] [Accepted: 05/05/2016] [Indexed: 01/09/2023] Open
Abstract
Recent advances in the chemistry of melanins have begun to disclose a number of important structure-property-function relationships of crucial relevance to the biological role of human pigments, including skin (photo) protection and UV-susceptibility. Even slight variations in the monomer composition of black eumelanins and red pheomelanins have been shown to determine significant differences in light absorption, antioxidant, paramagnetic and redox behavior, particle morphology, surface properties, metal chelation and resistance to photo-oxidative wear-and-tear. These variations are primarily governed by the extent of decarboxylation at critical branching points of the eumelanin and pheomelanin pathways, namely the rearrangement of dopachrome to 5,6-dihydroxyindole (DHI) and 5,6-dihydroxyindole-2-carboxylic acid (DHICA), and the rearrangement of 5-S-cysteinyldopa o-quinoneimine to 1,4-benzothiazine (BTZ) and its 3-carboxylic acid (BTZCA). In eumelanins, the DHICA-to-DHI ratio markedly affects the overall antioxidant and paramagnetic properties of the resulting pigments. In particular, a higher content in DHICA decreases visible light absorption and paramagnetic response relative to DHI-based melanins, but markedly enhances antioxidant properties. In pheomelanins, likewise, BTZCA-related units, prevalently formed in the presence of zinc ions, appear to confer pronounced visible and ultraviolet A (UVA) absorption features, accounting for light-dependent reactive oxygen species (ROS) production, whereas non-carboxylated benzothiazine intermediates seem to be more effective in inducing ROS production by redox cycling mechanisms in the dark. The possible biological and functional significance of carboxyl retention in the eumelanin and pheomelanin pathways is discussed.
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Ainger SA, Yong XL, Wong SS, Skalamera D, Gabrielli B, Leonard JH, Sturm RA. DCT protects human melanocytic cells from UVR and ROS damage and increases cell viability. Exp Dermatol 2015; 23:916-21. [PMID: 25346513 DOI: 10.1111/exd.12574] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/20/2014] [Indexed: 12/25/2022]
Abstract
Dopachrome tautomerase (DCT) is involved in the formation of the photoprotective skin pigment eumelanin and has also been shown to have a role in response to apoptotic stimuli and oxidative stress. The effect of DCT on UVR DNA damage responses and survival pathways in human melanocytic cells was examined by knockdown experiments using melanoma cells, neonatal foreskin melanoblasts (MB) in monoculture and in co-culture with human keratinocytes. MB cell strains genotyped as either MC1R WT or MC1R RHC homozygotes, which are known to be deficient in DCT, were transduced with lentivirus vectors for either DCT knockdown or overexpression. We found melanoma cell survival was reduced by DCT depletion and by UVR over time. UVR-induced p53 and pp53-Ser15 levels were reduced with DCT depletion. Knockdown of DCT in MC1R WT and MC1R RHC MB cells reduced their survival after UVR exposure, whereas increased DCT protein levels enhanced survival. DCT depletion reduced p53 and pp53-Ser15 levels in WM266-4 melanoma and MC1R WT MB cells, while MC1R RHC MB cells displayed variable levels. Both MC1R WT and RHC genotypes of MB cells were responsive to UVR at 3 h with increases in both p53 and pp53-Ser15 proteins. MC1R WT MB cell strains in coculture with keratinocytes have an increased cell survival after UVR exposure when compared to those in monoculture, a protective effect which appears to be conferred by the keratinocytes.
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Affiliation(s)
- Stephen A Ainger
- Institute for Molecular Bioscience, Melanogenix Group, The University of Queensland, Brisbane, Qld, Australia
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Mechanism of dopachrome tautomerization into 5,6-dihydroxyindole-2-carboxylic acid catalyzed by Cu(II) based on quantum chemical calculations. Biochim Biophys Acta Gen Subj 2014; 1850:281-6. [PMID: 25450182 DOI: 10.1016/j.bbagen.2014.10.024] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2014] [Revised: 10/18/2014] [Accepted: 10/21/2014] [Indexed: 12/18/2022]
Abstract
BACKGROUND Tautomerization of dopachrome to 5,6-dihydroxyindole-2-carboxylic acid (DHICA) is a biologically crucial reaction relevant to melanin synthesis, cellular antioxidation, and cross-talk among epidermal cells. Since dopachrome spontaneously converts into 5,6-dihydroxyindole (DHI) via decarboxylation without any enzymes at physiologically usual pH, the mechanism of how tautomerization to DHICA occurs in physiological system is a subject of intense debate. A previous work has found that Cu(II) is an important factor to catalyze the tautomerization of dopachrome to DHICA. However, the effect of Cu(II) on the tautomerization has not been clarified at the atomic level. METHODS We propose the reaction mechanism of the tautomerization to DHICA by Cu(II) from density functional theory-based calculation. RESULTS We clarified that the activation barriers of α-deprotonation, β-deprotonation, and decarboxylation from dopachrome are significantly reduced by coordination of Cu(II) to quinonoid oxygens (5,6-oxygens) of dopachrome, with the lowest activation barrier of β-deprotonation among them. In contrast to our previous work, in which β-deprotonation and quinonoid protonation (O5/O6-protonation) were shown to be important to form DHI, our results show that the Cu(II) coordination to quinonoid oxygens inhibits the quinonoid protonation, leading to the preference of proton rearrangement from β-carbon to carboxylate group but not to the quinonoid oxygens. CONCLUSION Integrating these results, we conclude that dopachrome tautomerization first proceeds via proton rearrangement from β-carbon to carboxylate group and subsequently undergoes α-deprotonation to form DHICA. GENERAL SIGNIFICANCE This study would provide the biochemical basis of DHICA metabolism and the generalized view of dopachrome conversion which is important to understand melanogenesis.
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14
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Corani A, Huijser A, Gustavsson T, Markovitsi D, Malmqvist PÅ, Pezzella A, d’Ischia M, Sundström V. Superior Photoprotective Motifs and Mechanisms in Eumelanins Uncovered. J Am Chem Soc 2014; 136:11626-35. [DOI: 10.1021/ja501499q] [Citation(s) in RCA: 74] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Affiliation(s)
- Alice Corani
- Department
of Chemical Physics, Lund University, Box 124, 22100 Lund, Sweden
| | - Annemarie Huijser
- Department
of Chemical Physics, Lund University, Box 124, 22100 Lund, Sweden
| | - Thomas Gustavsson
- CNRS, IRAMIS,
LIDYL, Laboratoire Francis Perrin, URA 2453, F-91191 Gif-sur-Yvette, France
| | - Dimitra Markovitsi
- CNRS, IRAMIS,
LIDYL, Laboratoire Francis Perrin, URA 2453, F-91191 Gif-sur-Yvette, France
| | - Per-Åke Malmqvist
- Division
of Theoretical Chemistry, Lund University, Box 124, 22100 Lund, Sweden
| | - Alessandro Pezzella
- Department
of Chemistry Sciences, University of Naples Federico II Via Cintia, 80126 Naples, Italy
| | - Marco d’Ischia
- Department
of Chemistry Sciences, University of Naples Federico II Via Cintia, 80126 Naples, Italy
| | - Villy Sundström
- Department
of Chemical Physics, Lund University, Box 124, 22100 Lund, Sweden
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15
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Cheung FK, Leung AWN, Liu WK, Che CT. Tyrosinase inhibitory activity of a glucosylated hydroxystilbene in mouse melan-a melanocytes. JOURNAL OF NATURAL PRODUCTS 2014; 77:1270-4. [PMID: 24933607 PMCID: PMC4076036 DOI: 10.1021/np4008798] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/17/2013] [Indexed: 05/19/2023]
Abstract
2,3,5,4'-Tetrahydroxystilbene-2-O-β-D-glucopyranoside (1), isolated from Polygonum multiflorum, is a noncompetitive inhibitor of tyrosinase in cell-free kinetics; it reduced the Vmax values in a dose-dependent manner. Compound 1 inhibited PKA-induced melanogenesis, reduced the protein expression of tyrosinase and its transcription factor, the microphthalmia-associated transcription factor, and lowered the complex formation between tyrosinase and tyrosinase-related protein 1 (TRP-1). Immunofluorescence microscopy revealed no association of tyrosinase with the endoplasmic reticulum or lysosomes, implying the absence of a direct effect of 1 on the maturation process of the enzyme. The antimelanogenic activity of 1 is likely mediated through a noncompetitive inhibition on tyrosinase, down-regulation of the expression of melanogenic proteins, and reduction of tyrosinase/TRP-1 complex formation.
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Affiliation(s)
- Florence
Wing-Ki Cheung
- School
of Biomedical Sciences, The Chinese University
of Hong Kong, Shatin, Hong Kong
- School
of Chinese Medicine, The Chinese University
of Hong Kong, Shatin, Hong Kong
| | | | - Wing Keung Liu
- School
of Biomedical Sciences, The Chinese University
of Hong Kong, Shatin, Hong Kong
| | - Chun-Tao Che
- School
of Chinese Medicine, The Chinese University
of Hong Kong, Shatin, Hong Kong
- Department
of Medicinal Chemistry and Pharmacognosy and WHO Collaborating Center
for Traditional Medicine, College of Pharmacy, University of Illinois at Chicago, Chicago, Illinois 60612, United States
- Tel: +1 312 996 5234. Fax: +1 312 996 7107. E-mail:
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16
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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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Panzella L, Leone L, Greco G, Vitiello G, D'Errico G, Napolitano A, d'Ischia M. Red human hair pheomelanin is a potent pro-oxidant mediating UV-independent contributory mechanisms of melanomagenesis. Pigment Cell Melanoma Res 2014; 27:244-52. [PMID: 24387634 DOI: 10.1111/pcmr.12199] [Citation(s) in RCA: 82] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2013] [Accepted: 11/26/2013] [Indexed: 12/29/2022]
Abstract
The highest incidence of melanoma in red haired individuals is attributed to the synthesis and phototoxic properties of pheomelanin pigments. Recently, pheomelanin has also been implicated in UV-independent pathways of oxidative stress; however, the underlying mechanisms have remained uncharted. Herein, we disclose the unprecedented property of purified red human hair pheomelanin (RHP) to promote (i) the oxygen-dependent depletion of major cell antioxidants, for example glutathione and NADH; (ii) the autoxidative formation of melanin pigments from their precursors. RHP would thus behave as a unique 'living' polymer and biocatalyst that may grow by simple exposure to monomer building blocks and may trigger autoxidative processes. These results yield new clues as to the origin of the pro-oxidant state in the red hair phenotype, uncover non-enzymatic pathways of melanogenesis, and pave the way to innovative strategies for melanoma prevention.
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Affiliation(s)
- Lucia Panzella
- Department of Chemical Sciences, University of Naples Federico II, Naples, Italy
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Panzella L, Gentile G, D'Errico G, Della Vecchia NF, Errico ME, Napolitano A, Carfagna C, d'Ischia M. Atypical Structural and π-Electron Features of a Melanin Polymer That Lead to Superior Free-Radical-Scavenging Properties. Angew Chem Int Ed Engl 2013. [DOI: 10.1002/ange.201305747] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Panzella L, Gentile G, D'Errico G, Della Vecchia NF, Errico ME, Napolitano A, Carfagna C, d'Ischia M. Atypical structural and π-electron features of a melanin polymer that lead to superior free-radical-scavenging properties. Angew Chem Int Ed Engl 2013; 52:12684-7. [PMID: 24123614 DOI: 10.1002/anie.201305747] [Citation(s) in RCA: 213] [Impact Index Per Article: 19.4] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2013] [Indexed: 11/12/2022]
Affiliation(s)
- Lucia Panzella
- Department of Chemical Sciences, University of Naples "Federico II", Via Cintia 4, 80126 Naples (Italy)
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Corani A, Pezzella A, Pascher T, Gustavsson T, Markovitsi D, Huijser A, d'Ischia M, Sundström V. Excited-State Proton-Transfer Processes of DHICA Resolved: From Sub-Picoseconds to Nanoseconds. J Phys Chem Lett 2013; 4:1383-1388. [PMID: 26282289 DOI: 10.1021/jz400437q] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Excited-state proton transfer has been hypothesized as a mechanism for UV energy dissipation in eumelanin skin pigments. By using time-resolved fluorescence spectroscopy, we show that the previously proposed, but unresolved, excited-state intramolecular proton transfer (ESIPT) of the eumelanin building block 5,6-dihydroxyindole-2-carboxylic acid (DHICA) occurs with a time constant of 300 fs in aqueous solution but completely stops in methanol. The previously disputed excited-state proton transfer involving the 5- or 6-OH groups of the DHICA anion is now found to occur from the 6-OH group to aqueous solvent with a rate constant of 4.0 × 10(8) s(-1).
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Affiliation(s)
- Alice Corani
- †Department of Chemical Physics, Lund University, Box 124, 22100 Lund, Sweden
| | - Alessandro Pezzella
- ‡Department of Chemical Sciences, University of Naples, Federico II Via Cintia, 80126 Naples, Italy
| | - Torbjörn Pascher
- †Department of Chemical Physics, Lund University, Box 124, 22100 Lund, Sweden
| | - Thomas Gustavsson
- §Laboratoire Francis Perrin, CEA/DSM/IRAMIS/SPAM-CNRS, URA 2453, CEA/Saclay, F-91191 Gif-sur-Yvette, France
| | - Dimitra Markovitsi
- §Laboratoire Francis Perrin, CEA/DSM/IRAMIS/SPAM-CNRS, URA 2453, CEA/Saclay, F-91191 Gif-sur-Yvette, France
| | - Annemarie Huijser
- †Department of Chemical Physics, Lund University, Box 124, 22100 Lund, Sweden
| | - Marco d'Ischia
- ‡Department of Chemical Sciences, University of Naples, Federico II Via Cintia, 80126 Naples, Italy
| | - Villy Sundström
- †Department of Chemical Physics, Lund University, Box 124, 22100 Lund, Sweden
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Abstract
Genome-wide association studies and comparative genomics have established major loci and specific polymorphisms affecting human skin, hair and eye color. Environmental changes have had an impact on selected pigmentation genes as populations have expanded into different regions of the globe.
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Affiliation(s)
- Richard A Sturm
- Institute for Molecular Bioscience, Melanogenix Group, The University of Queensland, Brisbane, Qld 4072, Australia.
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Wong SS, Ainger SA, Leonard JH, Sturm RA. MC1R variant allele effects on UVR-induced phosphorylation of p38, p53, and DDB2 repair protein responses in melanocytic cells in culture. J Invest Dermatol 2012; 132:1452-61. [PMID: 22336944 DOI: 10.1038/jid.2011.473] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Variant alleles of the human melanocortin 1 receptor (MC1R) reduce the ability of melanocytes to produce the dark pigment eumelanin, with R alleles being most deficient. Cultured melanocytes of MC1R R/R variant genotype give reduced responses to [Nle(4), D-Phe(7)]α-melanocyte-stimulating hormone (NDP-MSH) ligand stimulation and lower levels of DNA repair than MC1R wild-type strains. p38 controls xeroderma pigmentosum (XP)-C recruitment to DNA damage sites through regulating ubiquitylation of the DNA damage-binding protein 2 (DDB2) protein, and p53 is implicated in the nuclear excision repair process through its regulation of XP-C and DDB2 protein expression. We report the effects of MC1R ligand treatment and UVR exposure on phosphorylation of p38 and p53, and DDB2 protein expression in MC1R variant strains. Wild-type MC1R melanocyte strains grown together with keratinocytes in coculture, when treated with NDP-MSH and exposed to UVR, gave synergistic activation of p38 and p53 phosphorylation, and were not replicated by R/R variant melanocytes, which have lower basal levels of phosphorylated forms of p38. Minor increases in p38 phosphorylation status in R/R variant melanocyte cocultures could be attributed to the keratinocytes alone. We also found that MC1R wild-type strains regulate DDB2 protein levels through p38, but MC1R R/R variant melanocytes do not. This work confirms the important functional role that the MC1R receptor plays in UVR stress-induced DNA repair.
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Affiliation(s)
- Shu Shyan Wong
- Melanogenix Group, Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland, Australia
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The eumelanin intermediate 5,6-dihydroxyindole-2-carboxylic acid is a messenger in the cross-talk among epidermal cells. J Invest Dermatol 2012; 132:1196-205. [PMID: 22297637 DOI: 10.1038/jid.2011.457] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Interest in colorless intermediates of melanocyte metabolism has traditionally been related to their role as melanin precursors, though several lines of evidence scattered in the literature suggested that these compounds may exert an antioxidant and protective function per se unrelated to pigment synthesis. Herein, we disclose the remarkable protective and differentiating effects of 5,6-dihydroxyindole-2-carboxylic acid (DHICA), a diffusible dopachrome tautomerase (DCT)-dependent eumelanin intermediate, on primary cultures of human keratinocytes. At micromolar concentrations, DHICA induced: (a) time- and dose-dependent reduction of cell proliferation without concomitant toxicity; (b) enhanced expression of early (spinous keratins K1 and K10 and envelope protein involucrin) and late (loricrin and filaggrin) differentiation markers; (c) increased activities and expression of antioxidant enzymes; and (d) decreased cell damage and apoptosis following UVA exposure. The hitherto unrecognized role of DHICA as an antiproliferative, protective, and antiapoptotic endogenous cell messenger points to a reappraisal of the biological functions of melanocytes and DCT in skin homeostasis and photoprotection beyond the mere provision of melanin pigments, and provides, to our knowledge, a previously unreported possible explanation to the higher resistance of the dark-skinned eumelanic phenotypes to sunburn and skin cancer.
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Ainger SA, Wong SS, Roberts DW, Leonard JH, Sturm RA. Effect of MC1R variant allele status on MSH-ligand induction of dopachrome tautomerase in melanocytes co-cultured with keratinocytes. Exp Dermatol 2011; 20:681-4. [PMID: 21615505 DOI: 10.1111/j.1600-0625.2011.01293.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
A co-culture system of melanocytic cells and keratinocytes was used to examine dendricity and dopachrome tautomerase (DCT) responses in low penetrant 'r' homozygote and 'R/+' heterozygote MC1R variant allele expressing cells compared to that of wild-type (WT) cells. The V60L-/- homozygote r variant cells showed similar responses to ligand as WT MC1R strains, while V92M-/- homozygote r variant cells were generally shown to have greater dendricity and express higher DCT than the WT cells, even at basal levels. The R151C+/- heterozygote cells showed similar responses to WT cells, while the R160W+/- and D294H+/- variant cells were reduced in their responses to NDP-MSH, but still had an active cAMP response with forskolin treatment. These responses are consistent with the dominant negative effect of these alleles on the MC1R WT allele that has previously been demonstrated genetically and biochemically.
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