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Pena AM, Ito S, Bornschlögl T, Brizion S, Wakamatsu K, Del Bino S. Multiphoton FLIM Analyses of Native and UVA-Modified Synthetic Melanins. Int J Mol Sci 2023; 24. [PMID: 36901948 DOI: 10.3390/ijms24054517] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2023] [Revised: 02/14/2023] [Accepted: 02/21/2023] [Indexed: 03/02/2023] Open
Abstract
To better understand the impact of solar light exposure on human skin, the chemical characterization of native melanins and their structural photo-modifications is of central interest. As the methods used today are invasive, we investigated the possibility of using multiphoton fluorescence lifetime (FLIM) imaging, along with phasor and bi-exponential fitting analyses, as a non-invasive alternative method for the chemical analysis of native and UVA-exposed melanins. We demonstrated that multiphoton FLIM allows the discrimination between native DHI, DHICA, Dopa eumelanins, pheomelanin, and mixed eu-/pheo-melanin polymers. We exposed melanin samples to high UVA doses to maximize their structural modifications. The UVA-induced oxidative, photo-degradation, and crosslinking changes were evidenced via an increase in fluorescence lifetimes along with a decrease in their relative contributions. Moreover, we introduced a new phasor parameter of a relative fraction of a UVA-modified species and provided evidence for its sensitivity in assessing the UVA effects. Globally, the fluorescence lifetime properties were modulated in a melanin-dependent and UVA dose-dependent manner, with the strongest modifications being observed for DHICA eumelanin and the weakest for pheomelanin. Multiphoton FLIM phasor and bi-exponential analyses hold promising perspectives for in vivo human skin mixed melanins characterization under UVA or other sunlight exposure conditions.
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Bruning JM, Wang Y, Oltrabella F, Tian B, Kholodar SA, Liu H, Bhattacharya P, Guo S, Holton JM, Fletterick RJ, Jacobson MP, England PM. Covalent Modification and Regulation of the Nuclear Receptor Nurr1 by a Dopamine Metabolite. Cell Chem Biol 2019; 26:674-685.e6. [PMID: 30853418 PMCID: PMC7185887 DOI: 10.1016/j.chembiol.2019.02.002] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2018] [Revised: 11/06/2018] [Accepted: 01/31/2019] [Indexed: 12/20/2022]
Abstract
Nurr1, a nuclear receptor essential for the development, maintenance, and survival of midbrain dopaminergic neurons, is a potential therapeutic target for Parkinson's disease, a neurological disorder characterized by the degeneration of these same neurons. Efforts to identify Nurr1 agonists have been hampered by the recognition that it lacks several classic regulatory elements of nuclear receptor function, including the canonical ligand-binding pocket. Here we report that the dopamine metabolite 5,6-dihydroxyindole (DHI) binds directly to and modulates the activity of Nurr1. Using biophysical assays and X-ray crystallography, we show that DHI binds to the ligand-binding domain within a non-canonical pocket, forming a covalent adduct with Cys566. In cultured cells and zebrafish, DHI stimulates Nurr1 activity, including the transcription of target genes underlying dopamine homeostasis. These findings suggest avenues for developing synthetic Nurr1 ligands to ameliorate the symptoms and progression of Parkinson's disease.
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Affiliation(s)
- John M Bruning
- Pharmaceutical Sciences and Pharmacogenomics Graduate Program, University of California San Francisco, San Francisco, CA 94158, USA
| | - Yan Wang
- Department of Pharmaceutical Chemistry, University of California San Francisco, San Francisco, CA 94158, USA
| | - Francesca Oltrabella
- Department of Bioengineering and Therapeutic Sciences, University of California San Francisco, San Francisco, CA 94158, USA
| | - Boxue Tian
- Department of Pharmaceutical Chemistry, University of California San Francisco, San Francisco, CA 94158, USA
| | - Svetlana A Kholodar
- Department of Pharmaceutical Chemistry, University of California San Francisco, San Francisco, CA 94158, USA
| | - Harrison Liu
- Bioengineering Graduate Program, University of California San Francisco, San Francisco, CA 94158, USA
| | - Paulomi Bhattacharya
- Department of Pharmaceutical Chemistry, University of California San Francisco, San Francisco, CA 94158, USA
| | - Su Guo
- Department of Bioengineering and Therapeutic Sciences, University of California San Francisco, San Francisco, CA 94158, USA
| | - James M Holton
- Department of Biochemistry and Biophysics, University of California San Francisco, San Francisco, CA 94158, USA
| | - Robert J Fletterick
- Department of Biochemistry and Biophysics, University of California San Francisco, San Francisco, CA 94158, USA
| | - Matthew P Jacobson
- Department of Pharmaceutical Chemistry, University of California San Francisco, San Francisco, CA 94158, USA; Department of Bioengineering and Therapeutic Sciences, University of California San Francisco, San Francisco, CA 94158, USA
| | - Pamela M England
- Department of Pharmaceutical Chemistry, University of California San Francisco, San Francisco, CA 94158, USA; Department of Cellular and Molecular Pharmacology, University of California San Francisco, San Francisco, CA 94158, USA.
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Shanuja SK, Iswarya S, Gnanamani A. Marine fungal DHICA as a UVB protectant: Assessment under in vitro and in vivo conditions. J Photochem Photobiol B 2018; 179:139-148. [PMID: 29367149 DOI: 10.1016/j.jphotobiol.2018.01.010] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/24/2017] [Revised: 01/10/2018] [Accepted: 01/12/2018] [Indexed: 12/24/2022]
Abstract
The present study explores UVB protective role of a melanin precursor namely DHICA (5,6- Dihydroxyindole-2-carboxylic acid) expressed by the marine imperfect fungus Aspergillus nidulans. In brief, A. nidulans grown in a modified growth medium for the period of 5 days at 25 °C under shaking conditions and the extracellular medium free from fungal biomass used for the extraction of DHICA. The extracted DHICA further exposed to partial purification and subjected to UVB protection studies using HaCaT cells and Balb/c mice independently. DHICA obtained in the present study found soluble in water. Experiments on HaCaT cell compatibility revealed nil cell death up to 500 μM concentration of DHICA. UVB protection studies under in vitro conditions emphasizes DHICA significantly protect HaCaT cells from UVB exposure by quenching the generated ROS, reducing cell apoptosis, maintain the cellular integrity and sequentially down regulating the LPO (Lipid peroxidation) and up-regulating the antioxidant enzyme (SOD (Superoxide Dismutase), Catalase, GPx (Glutathione peroxidase)) respectively. Further, experiments on cell cycle arrest analysis, gelatin zymography, and western blot analysis on COX-2 and TNF-alpha, IHC (Immunohistochemistry) on apoptotic markers (Bax, Bcl2) substantiate the protective role of DHICA. Furthermore, in vivo studies on BALB/c mice carried out and compared with the sunscreen cream with sun protective factor (SPF) of 20. Analysis of skin sections of experimental samples revealed that an appreciable reduction in the epidermal thickness of the skin samples of mice pre-exposed to DHICA followed by UVB exposure compared to UVB exposure alone. RT-PCR results on various inflammatory apoptotic markers also suggested that DHICA has UVB protective potential. The observations made in the present study explore the possible application of DHICA alone as a sun-protective agent for skin care.
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Affiliation(s)
- S K Shanuja
- Microbiology Division, CSIR-CLRI, Adyar, Chennai 20, India
| | - S Iswarya
- Microbiology Division, CSIR-CLRI, Adyar, Chennai 20, India
| | - A Gnanamani
- Microbiology Division, CSIR-CLRI, Adyar, Chennai 20, India.
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Kishida R, Saputro AG, Kasai H. 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 2015; 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] [What about the content of this article? (0)] [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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Kishida R, Ushijima Y, Saputro AG, Kasai H. Effect of pH on elementary steps of dopachrome conversion from first-principles calculation. Pigment Cell Melanoma Res 2014; 27:734-43. [PMID: 24807014 DOI: 10.1111/pcmr.12256] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2014] [Accepted: 05/01/2014] [Indexed: 11/29/2022]
Abstract
Dopachrome conversion, in which dopachrome is converted into 5,6-dihydroxyindole (DHI) or 5,6-dihydroxyindole-2-carboxylic acid (DHICA) upstream of eumelanogenesis, is a key step in determining the DHI/DHICA monomer ratio in eumelanin, which affects the antioxidant activity. Although the ratio of DHI/DHICA formed and the conversion rate can be regulated depending on pH, the mechanism is still unclear. To clarify the mechanism, we carried out first-principles calculations. The results showed the kinetic preference of proton rearrangement to form quinone methide intermediate via β-deprotonation. We also identified possible pathways to DHI/DHICA from the quinone methide. The DHI formation can be achieved by spontaneous decarboxylation after proton rearrangement from carboxyl group to 6-oxygen. α-Deprotonation, which leads to DHICA formation, can also proceed with a significantly reduced activation barrier compared with that of the initial dopachrome. Considering the rate of the proton rearrangements in a given pH, we conclude that the conversion is suppressed at acidic pH.
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Affiliation(s)
- Ryo Kishida
- Department of Applied Physics, Osaka University, Suita, Osaka, Japan
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Pellosi MC, Suzukawa AA, Scalfo AC, Di Mascio P, Martins Pereira CP, de Souza Pinto NC, de Luna Martins D, Martinez GR. Effects of the melanin precursor 5,6-dihydroxy-indole-2-carboxylic acid ( DHICA) on DNA damage and repair in the presence of reactive oxygen species. Arch Biochem Biophys 2014; 557:55-64. [PMID: 24893147 DOI: 10.1016/j.abb.2014.05.024] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2014] [Revised: 05/15/2014] [Accepted: 05/26/2014] [Indexed: 01/26/2023]
Abstract
Eumelanin is a heterogeneous polymer composed of 5,6-dihydroxyindole-2-carboxylic acid (DHICA) and 5,6-dihydroxyindole (DHI). Studies have shown that DHICA promotes single strand breaks in plasmid DNA exposed to ultraviolet B radiation (UVB, 313 nm) and in DNA from human keratinocytes exposed to ultraviolet A radiation (UVA, 340-400 nm). Singlet molecular oxygen ((1)O2) is the main reactive species formed by UVA radiation on the skin. In this context, we now report that DHICA can cause single strand breaks in plasmid DNA even in the absence of light radiation. Interestingly, when DHICA was pre-oxidized by (1)O2, it lost this harmful capacity. It was also found that DHICA could interact with DNA, disturbing Fpg activity and decreasing its recognition of lesions by ∼50%. Additionally, the free nucleoside deoxyguanosine (dGuo) was used to evaluate whether DHICA would interfere with the formation of 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxodGuo) and spiroiminodihydantoin (dSp) by (1)O2 or with the formation of 8-oxodGuo by hydroxyl radical (OH). We observed that when dGuo was oxidized by (1)O2 in the presence of DHICA, 8-oxodGuo formation was increased. However, when dGuo was oxidized by OH in the presence of DHICA, 8-oxodGuo levels were lower than in the absence of the precursor. Overall, our data reveal an important role for this eumelanin precursor in both the promotion and the protection of DNA damage and imply that it can impair DNA repair.
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Affiliation(s)
- Maria Carolina Pellosi
- Programa de Pós-graduação em Ciências (Bioquímica), Departamento de Bioquímica e Biologia Molecular, Universidade Federal do Paraná, Curitiba, PR, Brazil
| | - Andréia Akemi Suzukawa
- Programa de Pós-graduação em Ciências (Bioquímica), Departamento de Bioquímica e Biologia Molecular, Universidade Federal do Paraná, Curitiba, PR, Brazil
| | | | - Paolo Di Mascio
- Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, São Paulo, SP, Brazil
| | | | | | | | - Glaucia Regina Martinez
- Programa de Pós-graduação em Ciências (Bioquímica), Departamento de Bioquímica e Biologia Molecular, Universidade Federal do Paraná, Curitiba, PR, Brazil.
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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] [What about the content of this article? (0)] [Affiliation(s)] [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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