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Li Y, Zeng Y, Chen Z, Tan X, Mei X, Wu Z. The role of aryl hydrocarbon receptor in vitiligo: a review. Front Immunol 2024; 15:1291556. [PMID: 38361944 PMCID: PMC10867127 DOI: 10.3389/fimmu.2024.1291556] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2023] [Accepted: 01/18/2024] [Indexed: 02/17/2024] Open
Abstract
Vitiligo is an acquired autoimmune dermatosis characterized by patchy skin depigmentation, causing significant psychological distress to the patients. Genetic susceptibility, environmental triggers, oxidative stress, and autoimmunity contribute to melanocyte destruction in vitiligo. Due to the diversity and complexity of pathogenesis, the combination of inhibiting melanocyte destruction and stimulating melanogenesis gives the best results in treating vitiligo. The aryl hydrocarbon receptor (AhR) is a ligand-activated transcription factor that can regulate the expression of various downstream genes and play roles in cell differentiation, immune response, and physiological homeostasis maintenance. Recent studies suggested that AhR signaling pathway was downregulated in vitiligo. Activation of AhR pathway helps to activate antioxidant pathways, inhibit abnormal immunity response, and upregulate the melanogenesis gene, thereby protecting melanocytes from oxidative stress damage, controlling disease progression, and promoting lesion repigmentation. Here, we review the relevant literature and summarize the possible roles of the AhR signaling pathway in vitiligo pathogenesis and treatment, to further understand the links between the AhR and vitiligo, and provide new potential therapeutic strategies.
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Affiliation(s)
- Yiting Li
- Department of Dermatology, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Yibin Zeng
- Department of Dermatology, Minhang Hospital, Fudan University, Shanghai, China
| | - Zile Chen
- Department of Dermatology, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Xi Tan
- Department of Dermatology, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Xingyu Mei
- Department of Dermatology, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Zhouwei Wu
- Department of Dermatology, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
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Bouchard KV, Costin GE. Promoting New Approach Methodologies (NAMs) for research on skin color changes in response to environmental stress factors: tobacco and air pollution. FRONTIERS IN TOXICOLOGY 2023; 5:1256399. [PMID: 37886123 PMCID: PMC10598764 DOI: 10.3389/ftox.2023.1256399] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2023] [Accepted: 08/25/2023] [Indexed: 10/28/2023] Open
Abstract
Aging is one of the most dynamic biological processes in the human body and is known to carry significant impacts on individuals' self-esteem. Skin pigmentation is a highly heritable trait made possible by complex, strictly controlled cellular and molecular mechanisms. Genetic, environmental and endocrine factors contribute to the modulation of melanin's amount, type and distribution in the skin layers. One of the hallmarks of extrinsic skin aging induced by environmental stress factors is the alteration of the constitutive pigmentation pattern clinically defined as senile lentigines and/or melasma or other pigmentary dyschromias. The complexity of pollutants and tobacco smoke as environmental stress factors warrants a thorough understanding of the mechanisms by which they impact skin pigmentation through repeated and long-term exposure. Pre-clinical and clinical studies demonstrated that pollutants are known to induce reactive oxygen species (ROS) or inflammatory events that lead directly or indirectly to skin hyperpigmentation. Another mechanistic direction is provided by Aryl hydrocarbon Receptors (AhR) which were shown to mediate processes leading to skin hyperpigmentation in response to pollutants by regulation of melanogenic enzymes and transcription factors involved in melanin biosynthesis pathway. In this context, we will discuss a diverse range of New Approach Methodologies (NAMs) capable to provide mechanistic insights of the cellular and molecular pathways involved in the action of environmental stress factors on skin pigmentation and to support the design of raw ingredients and formulations intended to counter their impact and of any subsequently needed clinical studies.
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Zhang T, Zhu L, Sun Y, Yang L, Yi S, Zhong W. Novel Insights on 6:6 Perfluoroalkyl Phosphonic Acid-Induced Melanin Synthesis Disorders Leading to Pigmentation in Tadpoles. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2023; 57:11032-11042. [PMID: 37467139 DOI: 10.1021/acs.est.3c02920] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/21/2023]
Abstract
As alternatives to traditional per- and polyfluoroalkyl substances, perfluoroalkyl phosphonic acids (PFPiAs) are widely present in aquatic environments and can potentially harm aquatic organisms. Pigmentation affects the probability of aquatic organisms being preyed on and serves as an important toxic endpoint of development, but little is known about the impacts of PFPiAs on the development of aquatic organisms. In this study, Xenopus laevis embryos were exposed to 6:6 PFPiA (1, 10, and 100 nM) for 14 days. The developed tadpoles exhibited evident pigmentation with increased melanin particle size and density on the skin. Pathological and behavioral experiments revealed that the retinal layers became thinner, reducing the photosensitivity and disturbing the circadian rhythm of the tadpoles. Compared to the control group, the exposed tadpoles showed higher levels but less changes of melanin throughout the light/dark cycle, as well as distinct oxidative damage. Consequently, the expression level of microphthalmia-associated transcription factor (MITF), a key factor inducing melanin synthesis, increased significantly. Molecular docking analysis suggested that 6:6 PFPiA forms strong interactions in the binding pocket of MITF, implying that it could activate MITF directly. The activation of MITF ultimately promotes melanin synthesis, resulting in pigmentation on tadpoles.
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Affiliation(s)
- Tianxu Zhang
- Key Laboratory of Pollution Processes and Environmental Criteria of Ministry of Education, Tianjin Key Laboratory of Environmental Remediation and Pollution Control, College of Environmental Science and Engineering of Nankai University, Tianjin 300350, China
| | - Lingyan Zhu
- Key Laboratory of Pollution Processes and Environmental Criteria of Ministry of Education, Tianjin Key Laboratory of Environmental Remediation and Pollution Control, College of Environmental Science and Engineering of Nankai University, Tianjin 300350, China
| | - Yumeng Sun
- Key Laboratory of Pollution Processes and Environmental Criteria of Ministry of Education, Tianjin Key Laboratory of Environmental Remediation and Pollution Control, College of Environmental Science and Engineering of Nankai University, Tianjin 300350, China
| | - Liping Yang
- Key Laboratory of Pollution Processes and Environmental Criteria of Ministry of Education, Tianjin Key Laboratory of Environmental Remediation and Pollution Control, College of Environmental Science and Engineering of Nankai University, Tianjin 300350, China
| | - Shujun Yi
- Key Laboratory of Pollution Processes and Environmental Criteria of Ministry of Education, Tianjin Key Laboratory of Environmental Remediation and Pollution Control, College of Environmental Science and Engineering of Nankai University, Tianjin 300350, China
| | - Wenjue Zhong
- Key Laboratory of Pollution Processes and Environmental Criteria of Ministry of Education, Tianjin Key Laboratory of Environmental Remediation and Pollution Control, College of Environmental Science and Engineering of Nankai University, Tianjin 300350, China
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Chen Y, Wang Y, Fu Y, Yin Y, Xu K. Modulating AHR function offers exciting therapeutic potential in gut immunity and inflammation. Cell Biosci 2023; 13:85. [PMID: 37179416 PMCID: PMC10182712 DOI: 10.1186/s13578-023-01046-y] [Citation(s) in RCA: 12] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2023] [Accepted: 05/04/2023] [Indexed: 05/15/2023] Open
Abstract
Aryl hydrocarbon receptor (AHR) is a ligand-dependent transcription factor. 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) is a classical exogenous synthetic ligand of AHR that has significant immunotoxic effects. Activation of AHR has beneficial effects on intestinal immune responses, but inactivation or overactivation of AHR can lead to intestinal immune dysregulation and even intestinal diseases. Sustained potent activation of AHR by TCDD results in impairment of the intestinal epithelial barrier. However, currently, AHR research has been more focused on elucidating physiologic AHR function than on dioxin toxicity. The appropriate level of AHR activation plays a role in maintaining gut health and protecting against intestinal inflammation. Therefore, AHR offers a crucial target to modulate intestinal immunity and inflammation. Herein, we summarize our current understanding of the relationship between AHR and intestinal immunity, the ways in which AHR affects intestinal immunity and inflammation, the effects of AHR activity on intestinal immunity and inflammation, and the effect of dietary habits on intestinal health through AHR. Finally, we discuss the therapeutic role of AHR in maintaining gut homeostasis and relieving inflammation.
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Affiliation(s)
- Yue Chen
- Key Laboratory of Agro-ecological Processes in Subtropical Region, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha, 410125, China
- College of Animal Science and Technology, Henan Agricultural University, Zhengzhou, 450000, China
| | - Yadong Wang
- Key Laboratory of Agro-ecological Processes in Subtropical Region, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha, 410125, China
| | - Yawei Fu
- Key Laboratory of Agro-ecological Processes in Subtropical Region, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha, 410125, China
- College of Animal Science and Technology, Henan Agricultural University, Zhengzhou, 450000, China
| | - Yulong Yin
- Key Laboratory of Agro-ecological Processes in Subtropical Region, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha, 410125, China
- College of Animal Science and Technology, Henan Agricultural University, Zhengzhou, 450000, China
| | - Kang Xu
- Key Laboratory of Agro-ecological Processes in Subtropical Region, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha, 410125, China.
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5
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Ghaffarian-Bahraman A, Arabnezhad MR, Keshavarzi M, Davani-Davari D, Jamshidzadeh A, Mohammadi-Bardbori A. Influence of cellular redox environment on aryl hydrocarbon receptor ligands induced melanogenesis. Toxicol In Vitro 2021; 79:105282. [PMID: 34856342 DOI: 10.1016/j.tiv.2021.105282] [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: 07/24/2021] [Revised: 10/07/2021] [Accepted: 11/23/2021] [Indexed: 11/25/2022]
Abstract
Many environmental pollutants, natural compounds, as well as endogenous chemicals exert their biological/toxicological effects by reacting with the aryl hydrocarbon receptor (AhR). Previous evidence shed new light on the role of AhR in skin physiology by regulating melanin production. In this study, we investigated the effect of oxidative imbalance induced by AhR ligands on the melanogenesis process in B16 murine melanoma cells. Exposure to 6-formylindolo[3,2-b] carbazole (FICZ) or benzo-α-pyrene (BαP) led to enhanced expression of CTNNB1, MITF, and TYR genes following increased tyrosinase enzyme activity and melanin content in an AhR-dependent manner. Analysis of the presence of reactive oxygen species (ROS) as well as reduced glutathione (GSH) / oxidized glutathione (GSSG) ratio revealed that treatment with AhR ligands is associated with oxidative stress which can be ameliorated with NAC (N-acetyl cysteine) or diphenyleneiodonium chloride (DPI). On the other hand, NAC and DPI enhanced melanogenesis induced by AhR ligands by reducing the level of ROS. We have shown for the first time that a cellular redox status is a critical event during AhR ligand-induced melanogenesis.
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Affiliation(s)
- Ali Ghaffarian-Bahraman
- Occupational Environment Research Center, Rafsanjan University of Medical Sciences, Rafsanjan, Iran; Department of Pharmacology and Toxicology, School of Pharmacy, Shiraz University of Medical Sciences, Shiraz, Fars, Iran
| | - Mohammad-Reza Arabnezhad
- Department of Toxicology and Pharmacology, Faculty of Pharmacy, Kerman University of Medical Sciences, Kerman, Iran
| | - Majid Keshavarzi
- Department of Environmental Health Engineering, School of Public Health, Sabzevar University of Medical Sciences, Sabzevar, Iran
| | - Dorna Davani-Davari
- Department of Pharmacology and Toxicology, School of Pharmacy, Shiraz University of Medical Sciences, Shiraz, Fars, Iran
| | - Akram Jamshidzadeh
- Department of Pharmacology and Toxicology, School of Pharmacy, Shiraz University of Medical Sciences, Shiraz, Fars, Iran
| | - Afshin Mohammadi-Bardbori
- Department of Pharmacology and Toxicology, School of Pharmacy, Shiraz University of Medical Sciences, Shiraz, Fars, Iran.
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Ferreira Branquinho MS, Silva MBB, Castilho GA, Cavalcante J, Barros SBDM, Clara RO, Maria-Engler SS, Campa A. Kynurenine inhibits melanogenesis in human melanocyte-keratinocyte co-cultures and in a reconstructed 3D skin model. Exp Dermatol 2021; 31:427-432. [PMID: 34710259 DOI: 10.1111/exd.14486] [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: 07/23/2021] [Revised: 09/07/2021] [Accepted: 10/22/2021] [Indexed: 11/28/2022]
Abstract
Kynurenine (KYN), the most abundant metabolite of tryptophan, is classically associated with immune tolerance and tumor immune escape. In the last years, KYN is in the spotlight in other biological processes. Here, we showed that KYN inhibited tyrosinase expression and melanin content in primary human melanocyte and keratinocyte co-cultures. Furthermore, KYN decreased melanosome content in a 3D human skin reconstruction model. In these experiments, we used tyrosine + NH4 Cl to induce pigmentation. We compared the inhibitory effect of KYN on melanogenesis with the already known inhibitory effect promoted by IFN-γ. Since increased KYN production depends on the IFN-γ-inducible enzyme indoleamine-2,3-dioxygenase (IDO), we propose that part of the effect of IFN-γ on melanogenesis involves KYN production. From that, we tested if, during melanogenesis, changes in tryptophan metabolism would occur. For this purpose, we measured tryptophan, KYN and downstream products along with pigmentation. There were no significant changes in Trp metabolism, except for the high consumption of kynurenic acid. Our data identify the skin as a potential target for the action of KYN relevant for skin physiology and pigmentation. The results are discussed concerning the high production of KYN in skin inflammatory disorders and cancer.
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Affiliation(s)
| | - Maysa Braga Barros Silva
- Faculty of Pharmaceutical Sciences, Department of Clinical Chemistry and Toxicology, University of Sao Paulo, Sao Paulo, Brazil
| | - Gabriela Ansanelo Castilho
- Faculty of Pharmaceutical Sciences, Department of Clinical Chemistry and Toxicology, University of Sao Paulo, Sao Paulo, Brazil
| | - Jacqueline Cavalcante
- Faculty of Pharmaceutical Sciences, Department of Clinical Chemistry and Toxicology, University of Sao Paulo, Sao Paulo, Brazil
| | - Silvia Berlanga de Moraes Barros
- Skin Lab, Faculty of Pharmaceutical Sciences, Department of Clinical Chemistry and Toxicology, University of Sao Paulo, Sao Paulo, Brazil
| | - Renan Orsati Clara
- Faculty of Pharmaceutical Sciences, Department of Clinical Chemistry and Toxicology, University of Sao Paulo, Sao Paulo, Brazil
| | - Silvya Stuchi Maria-Engler
- Skin Lab, Faculty of Pharmaceutical Sciences, Department of Clinical Chemistry and Toxicology, University of Sao Paulo, Sao Paulo, Brazil
| | - Ana Campa
- Faculty of Pharmaceutical Sciences, Department of Clinical Chemistry and Toxicology, University of Sao Paulo, Sao Paulo, Brazil
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7
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Xu M, Mehl L, Zhang T, Thakur R, Sowards H, Myers T, Jessop L, Chesi A, Johnson ME, Wells AD, Michael HT, Bunda P, Jones K, Higson H, Hennessey RC, Jermusyk A, Kovacs MA, Landi MT, Iles MM, Goldstein AM, Choi J, Chanock SJ, Grant SF, Chari R, Merlino G, Law MH, Brown KM, Brown KM. A UVB-responsive common variant at chromosome band 7p21.1 confers tanning response and melanoma risk via regulation of the aryl hydrocarbon receptor, AHR. Am J Hum Genet 2021; 108:1611-1630. [PMID: 34343493 DOI: 10.1016/j.ajhg.2021.07.002] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Accepted: 07/07/2021] [Indexed: 10/20/2022] Open
Abstract
Genome-wide association studies (GWASs) have identified a melanoma-associated locus on chromosome band 7p21.1 with rs117132860 as the lead SNP and a secondary independent signal marked by rs73069846. rs117132860 is also associated with tanning ability and cutaneous squamous cell carcinoma (cSCC). Because ultraviolet radiation (UVR) is a key environmental exposure for all three traits, we investigated the mechanisms by which this locus contributes to melanoma risk, focusing on cellular response to UVR. Fine-mapping of melanoma GWASs identified four independent sets of candidate causal variants. A GWAS region-focused Capture-C study of primary melanocytes identified physical interactions between two causal sets and the promoter of the aryl hydrocarbon receptor (AHR). Subsequent chromatin state annotation, eQTL, and luciferase assays identified rs117132860 as a functional variant and reinforced AHR as a likely causal gene. Because AHR plays critical roles in cellular response to dioxin and UVR, we explored links between this SNP and AHR expression after both 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) and ultraviolet B (UVB) exposure. Allele-specific AHR binding to rs117132860-G was enhanced following both, consistent with predicted weakened AHR binding to the risk/poor-tanning rs117132860-A allele, and allele-preferential AHR expression driven from the protective rs117132860-G allele was observed following UVB exposure. Small deletions surrounding rs117132860 introduced via CRISPR abrogates AHR binding, reduces melanocyte cell growth, and prolongs growth arrest following UVB exposure. These data suggest AHR is a melanoma susceptibility gene at the 7p21.1 risk locus and rs117132860 is a functional variant within a UVB-responsive element, leading to allelic AHR expression and altering melanocyte growth phenotypes upon exposure.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | - Kevin M Brown
- Laboratory of Translational Genomics, Division of Cancer Epidemiology and Genetics, National Cancer Institute, Bethesda, MD 20892, USA.
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Shi Y, Zeng Z, Liu J, Pi Z, Zou P, Deng Q, Ma X, Qiao F, Xiong W, Zhou C, Zeng Q, Xiao R. Particulate matter promotes hyperpigmentation via AhR/MAPK signaling activation and by increasing α-MSH paracrine levels in keratinocytes. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2021; 278:116850. [PMID: 33711628 DOI: 10.1016/j.envpol.2021.116850] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/18/2020] [Revised: 02/22/2021] [Accepted: 02/23/2021] [Indexed: 06/12/2023]
Abstract
Particulate matter with an aerodynamic equivalent diameter of 2.5 μm or less in ambient air (PM2.5) has become a global public and environmental problem, and the control of the PM2.5 concentration in air is an urgent problem. PM2.5 can easily penetrate the skin, activating the inflammatory response in skin, unbalancing the skin barrier function, and inducing skin aging. Hyperpigmentation is the main manifestation of skin aging and has a considerable impact on quality of life worldwide. To date, no research on the influence of PM2.5 on hyperpigmentation has been conducted. Here, we illustrate that PM2.5 can induce melanogenesis in vivo and in vitro by regulating TYR, TYRP1, TYRP2, and MITF expression via AhR/MAPK signaling activation. Furthermore, PM2.5 increased α-MSH paracrine levels, which in turn promote hyperpigmentation. Our results provide a deeper understanding of how PM2.5 disrupts skin homeostasis and function. Treatment with AhR antagonists may be a potential therapeutic strategy for hyperpigmentation induced by PM2.5.
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Affiliation(s)
- Yaqian Shi
- Department of Dermatology, The Second Xiangya Hospital, Central South University, Changsha, Hunan, 410011, China; Hunan Key Laboratory of Medical Epigenetics, The Second Xiangya Hospital, Central South University, Changsha, Hunan, 410011, China
| | - Zhuotong Zeng
- Department of Dermatology, The Second Xiangya Hospital, Central South University, Changsha, Hunan, 410011, China; Hunan Key Laboratory of Medical Epigenetics, The Second Xiangya Hospital, Central South University, Changsha, Hunan, 410011, China
| | - Jiani Liu
- Department of Dermatology, The Second Xiangya Hospital, Central South University, Changsha, Hunan, 410011, China; Hunan Key Laboratory of Medical Epigenetics, The Second Xiangya Hospital, Central South University, Changsha, Hunan, 410011, China
| | - Zixin Pi
- Department of Dermatology, The Second Xiangya Hospital, Central South University, Changsha, Hunan, 410011, China; Hunan Key Laboratory of Medical Epigenetics, The Second Xiangya Hospital, Central South University, Changsha, Hunan, 410011, China
| | - Puyu Zou
- Department of Dermatology, The Second Xiangya Hospital, Central South University, Changsha, Hunan, 410011, China; Hunan Key Laboratory of Medical Epigenetics, The Second Xiangya Hospital, Central South University, Changsha, Hunan, 410011, China
| | - Qiancheng Deng
- Department of Dermatology, The First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, Zhejiang, 310003, China
| | - Xinyu Ma
- Department of Dermatology, The Second Xiangya Hospital, Central South University, Changsha, Hunan, 410011, China; Hunan Key Laboratory of Medical Epigenetics, The Second Xiangya Hospital, Central South University, Changsha, Hunan, 410011, China
| | - Fan Qiao
- Department of Dermatology, The Second Xiangya Hospital, Central South University, Changsha, Hunan, 410011, China; Hunan Key Laboratory of Medical Epigenetics, The Second Xiangya Hospital, Central South University, Changsha, Hunan, 410011, China
| | - Weiping Xiong
- College of Environmental Science and Engineering, Hunan University and Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha, Hunan, 410082, China
| | - Chengyun Zhou
- College of Environmental Science and Engineering, Hunan University and Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha, Hunan, 410082, China
| | - Qinghai Zeng
- Department of Dermatology, Third Xiangya Hospital, Central South University, Changsha, Hunan, 410000, China
| | - Rong Xiao
- Department of Dermatology, The Second Xiangya Hospital, Central South University, Changsha, Hunan, 410011, China; Hunan Key Laboratory of Medical Epigenetics, The Second Xiangya Hospital, Central South University, Changsha, Hunan, 410011, China.
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A New Insight into the Potential Role of Tryptophan-Derived AhR Ligands in Skin Physiological and Pathological Processes. Int J Mol Sci 2021; 22:ijms22031104. [PMID: 33499346 PMCID: PMC7865493 DOI: 10.3390/ijms22031104] [Citation(s) in RCA: 34] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2020] [Revised: 01/15/2021] [Accepted: 01/19/2021] [Indexed: 12/31/2022] Open
Abstract
The aryl hydrocarbon receptor (AhR) plays a crucial role in environmental responses and xenobiotic metabolism, as it controls the transcription profiles of several genes in a ligand-specific and cell-type-specific manner. Various barrier tissues, including skin, display the expression of AhR. Recent studies revealed multiple roles of AhR in skin physiology and disease, including melanogenesis, inflammation and cancer. Tryptophan metabolites are distinguished among the groups of natural and synthetic AhR ligands, and these include kynurenine, kynurenic acid and 6-formylindolo[3,2-b]carbazole (FICZ). Tryptophan derivatives can affect and regulate a variety of signaling pathways. Thus, the interest in how these substances influence physiological and pathological processes in the skin is expanding rapidly. The widespread presence of these substances and potential continuous exposure of the skin to their biological effects indicate the important role of AhR and its ligands in the prevention, pathogenesis and progression of skin diseases. In this review, we summarize the current knowledge of AhR in skin physiology. Moreover, we discuss the role of AhR in skin pathological processes, including inflammatory skin diseases, pigmentation disorders and cancer. Finally, the impact of FICZ, kynurenic acid, and kynurenine on physiological and pathological processes in the skin is considered. However, the mechanisms of how AhR regulates skin function require further investigation.
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10
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Noakes R. Frontal Fibrosing Alopecia. An Example of Disrupted Aryl Hydrocarbon Receptor-Mediated Immunological Homeostasis in the Skin? Clin Cosmet Investig Dermatol 2020; 13:479-484. [PMID: 32801823 PMCID: PMC7399449 DOI: 10.2147/ccid.s262803] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2020] [Accepted: 07/08/2020] [Indexed: 01/19/2023]
Abstract
Sun protection has been recommended by public health authorities to reduce the risk of keratinocyte and melanocyte tumors, yet some sun exposure is required for vitamin D synthesis. Frontal fibrosing alopecia (FFA) is a cicatricial alopecia that has been reported to have an association with facial photoprotection. The brief review proposes the hypothesis that FFA arises as a result of excessive facial photo-protection with a resultant disturbance in immunological homeostasis mediated via the aryl hydrocarbon receptor-kynurenine pathway axis (AHR/KP) leading to the collapse of immune privilege at the hair bulge.
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Affiliation(s)
- Rowland Noakes
- Queensland Institute of Dermatology, South Brisbane, Queensland, Australia
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11
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Idowu O, Semple KT, Ramadass K, O'Connor W, Hansbro P, Thavamani P. Analysis of polycyclic aromatic hydrocarbons (PAHs) and their polar derivatives in soils of an industrial heritage city of Australia. THE SCIENCE OF THE TOTAL ENVIRONMENT 2020; 699:134303. [PMID: 33736201 DOI: 10.1016/j.scitotenv.2019.134303] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/31/2019] [Revised: 09/03/2019] [Accepted: 09/03/2019] [Indexed: 05/27/2023]
Abstract
Knowledge about polar derivatives of polycyclic aromatic hydrocarbons (PAHs) in soils is limited despite the extensive study of the environmental presence and persistence of non-polar parent PAHs. Polar PAHs have greater potential to be more toxic at low environmental concentrations compared to their homocyclic analogues. For both polar and non-polar PAHs, combustion of fossil fuels is often the main source especially in industrialised environments. This study investigated the concentration profiles of PAHs and its associated polar PAHs such as nitrated PAHs (NPAHs), oxygenated PAHs (oxy-PAHs) and nitrogen, sulphur and oxygen heterocyclic PAHs (N/S/O-heterocyclic PAHs) in a well-known industrial heritage city of Australia. The most abundant polar PAHs were 9-fluorenone (oxy-PAHs), 2-nitrofluorene (NPAHs) and carbazole (heterocyclic-PAHs). A positive correlation (r = 0.5, p < 0.01) between ∑13PAHs and ∑19 polar PAHs was observed, implying a possible spatial association between parent and polar PAHs. The concentrations of polar PAHs in soil samples, across various landuse patterns, were used to calculate the excess lifetime cancer risk (ELCR) from incidental ingestion of soils. The computed ELCR values ranged from 8.2*10-7 (industrial soils) to 2.3*10-6 (residential soils), indicating negligible cancer risks. This is the first known study on the occurrence and concentrations of polar and non-polar PAHs in any Australian city, and the results may serve a baseline purpose for improved risk assessment of contaminated sites.
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Affiliation(s)
- Oluyoye Idowu
- Global Centre for Environmental Remediation (GCER), University of Newcastle, Callaghan, NSW 2308, Australia
| | - Kirk T Semple
- Lancaster Environment Centre, Lancaster University, Lancaster LA1 4YQ, United Kingdom
| | - Kavitha Ramadass
- Global Innovative Centre for Advanced Nanomaterials (GICAN), University of Newcastle, Callaghan, NSW 2308, Australia
| | - Wayne O'Connor
- Port Stephens Fisheries Institute, NSW Department of Primary Industries, Port Stephens, NSW 2316, Australia
| | - Phil Hansbro
- Centre for Inflammation, Centenary Institute, Sydney, NSW 2050, Australia; University of Technology Sydney, Faculty of Science, Ultimo, NSW 2007, Australia
| | - Palanisami Thavamani
- Global Centre for Environmental Remediation (GCER), University of Newcastle, Callaghan, NSW 2308, Australia.
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Furue M, Tsuji G. Chloracne and Hyperpigmentation Caused by Exposure to Hazardous Aryl Hydrocarbon Receptor Ligands. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2019; 16:ijerph16234864. [PMID: 31816860 PMCID: PMC6926551 DOI: 10.3390/ijerph16234864] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/21/2019] [Revised: 11/26/2019] [Accepted: 12/02/2019] [Indexed: 12/12/2022]
Abstract
Dioxins and dioxin-like compounds are environmental pollutants that are hazardous to human skin. They can be present in contaminated soil, water, and air particles (such as ambient PM2.5). Exposure to a high concentration of dioxins induces chloracne and hyperpigmentation. These chemicals exert their toxic effects by activating the aryl hydrocarbon receptor (AHR) which is abundantly expressed in skin cells, such as keratinocytes, sebocytes, and melanocytes. Ligation of AHR by dioxins induces exaggerated acceleration of epidermal terminal differentiation (keratinization) and converts sebocytes toward keratinocyte differentiation, which results in chloracne formation. AHR activation potently upregulates melanogenesis in melanocytes by upregulating the expression of melanogenic enzymes, which results in hyperpigmentation. Because AHR-mediated oxidative stress contributes to these hazardous effects, antioxidative agents may be potentially therapeutic for chloracne and hyperpigmentation.
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Affiliation(s)
- Masutaka Furue
- Department of Dermatology, Graduate School of Medical Sciences, Kyushu University, Maidashi 3-1-1, Higashiku, Fukuoka 812-8582, Japan;
- Research and Clinical Center for Yusho and Dioxin, Kyushu University, Maidashi 3-1-1, Higashiku, Fukuoka 812-8582, Japan
- Division of Skin Surface Sensing, Graduate School of Medical Sciences, Kyushu University, Maidashi 3-1-1, Higashiku, Fukuoka 812-8582, Japan
- Correspondence: ; Tel.: +81-92-642-5581; Fax: +81-92-642-5600
| | - Gaku Tsuji
- Department of Dermatology, Graduate School of Medical Sciences, Kyushu University, Maidashi 3-1-1, Higashiku, Fukuoka 812-8582, Japan;
- Research and Clinical Center for Yusho and Dioxin, Kyushu University, Maidashi 3-1-1, Higashiku, Fukuoka 812-8582, Japan
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Peng F, Tsuji G, Zhang JZ, Chen Z, Furue M. Potential role of PM 2.5 in melanogenesis. ENVIRONMENT INTERNATIONAL 2019; 132:105063. [PMID: 31394397 DOI: 10.1016/j.envint.2019.105063] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/04/2019] [Revised: 07/04/2019] [Accepted: 07/25/2019] [Indexed: 06/10/2023]
Abstract
Ambient particulate matter 2.5 (PM2.5) is one of the main components of air pollutants, which can absorb many polycyclic aromatic hydrocarbons and metals. The effect of PM2.5 on human skin and its biological significance in skin homeostasis remain incompletely understood. Previous studies demonstrated that PM2.5 can activate aryl hydrocarbon receptor (AhR), generate reactive oxygen species, and induce skin inflammation. These processes may be involved in melanocyte homeostasis and melanogenesis. We hypothesize that AhR signaling may be responsible for PM2.5-related hyperpigmentation.
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Affiliation(s)
- Fen Peng
- Department of Dermatology, Peking University People's Hospital, Beijing 100044, China
| | - Gaku Tsuji
- Department of Dermatology, Graduate School of Medicine, Faculty of Medical Sciences, Kyushu University, Fukuoka 812-8582, Japan; Research and Clinical Center for Yusho and Dioxin, Kyushu University Hospital, Fukuoka 812-8582, Japan.
| | - Jian-Zhong Zhang
- Department of Dermatology, Peking University People's Hospital, Beijing 100044, China
| | - Zhou Chen
- Department of Dermatology, Peking University People's Hospital, Beijing 100044, China
| | - Masutaka Furue
- Department of Dermatology, Graduate School of Medicine, Faculty of Medical Sciences, Kyushu University, Fukuoka 812-8582, Japan; Research and Clinical Center for Yusho and Dioxin, Kyushu University Hospital, Fukuoka 812-8582, Japan; Division of Skin Surface Sensing, Department of Dermatology, Graduate School of Medicine, Faculty of Medical Sciences, Kyushu University, Fukuoka 812-8582, Japan.
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Milani M, Hashtroody B, Piacentini M, Celleno L. Skin protective effects of an antipollution, antioxidant serum containing Deschampsia antartica extract, ferulic acid and vitamin C: a controlled single-blind, prospective trial in women living in urbanized, high air pollution area. Clin Cosmet Investig Dermatol 2019; 12:393-399. [PMID: 31213870 PMCID: PMC6549792 DOI: 10.2147/ccid.s204905] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2019] [Accepted: 05/07/2019] [Indexed: 01/02/2023]
Abstract
Introduction: Air pollution causes skin damage and favors skin aging processes such as dark spots and wrinkles, through oxidative stress. Pollutant substances accelerate skin aging through a specific activation of intracellular receptors called AhR (aryl-hydrocarbon receptors). Deschampsia antartica aqueous extract (DAE) has shown to counteract the pollutant-induced AhR activation. Ferulic acid (FA) and vitamin C (VC) are potent antioxidant substances. A serum containing DAE/FA/VC has been recently developed. So far, no clinical data are available regarding the protective actions of this serum against the detrimental effects of air pollution on the skin. Objective: We conducted a prospective, single-blind, 28-day study to assess efficacy and protective effects against air pollution skin damage of a new serum containing Deschampsia antartica extract. Materials and methods: Twenty, photo type I-III, women (mean age 42 years) with at least three dark spots on the face, living in a homogenous urbanized, high pollution area (Rome) were evaluated. The objectives of the study were to evaluate the effects of treatment on skin barrier function, assessed by transepidermal water loss (TEWL) measurement (Tewameter), the effect on dark spots, evaluated by means of colorimetry (Colorimeter CL 400), and the effect on squalene peroxide (SQOOH)/squalene (SQ) skin ratio assessed with face swabs. Results: The trial was conducted between November 20 and December 19, 2018. In comparison with baseline, the product induced a significant improvement of skin hydration (-19% of TEWL), a significant improvement of dark spots (+7%) and a significant improvement of SQOOH/SQ ratio (-16%). The product was evaluated very well by >90% of the treated subjects regarding cosmetic acceptability. Discussion: A serum containing DAE/FA/VC has shown to improve skin barrier function, to reduce dark spots and to counteract the skin oxidative stress in women living in high pollution urban area.
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Affiliation(s)
- Massimo Milani
- Medical Department, Cantabria Labs Difa Cooper, Caronno P, VA, Italy
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Jang HS, Lee JE, Myung CH, Park JI, Jo CS, Hwang JS. Particulate Matter-Induced Aryl Hydrocarbon Receptor Regulates Autophagy in Keratinocytes. Biomol Ther (Seoul) 2019; 27:570-576. [PMID: 30971064 PMCID: PMC6824630 DOI: 10.4062/biomolther.2019.025] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2019] [Revised: 03/14/2019] [Accepted: 03/18/2019] [Indexed: 12/13/2022] Open
Abstract
Particulate matter (PM), which refers to the mixture of particles present in the air, can have harmful effects. Damage to cells by PM, including disruption of organelles and proteins, can trigger autophagy, and the relationship between autophagy and PM has been well studied. However, the cellular regulators of PM-induced autophagy have not been well characterized, especially in keratinocytes. The Aryl Hydrocarbon Receptor (AhR) is expressed in the epidermis and is activated by PM. In this study, we investigated the role of the AhR in PM-induced autophagy in HaCaT cells. Our results showed that PM led to AhR activation in keratinocytes. Activation of the AhR-target gene CYP1A1 by PM was reduced by co-treatment with α-naphthoflavone (α-NF), an AhR inhibitor. We also evaluated activation of the autophagy pathway in PM-treated keratinocytes. In HaCaT cells, treatment with PM treatment led to the induction of microtubules-associated proteins light chain 3 (LC3) and p62/SQSTM1, which are essential components of the autophagy pathway. To study the role of the AhR in mediating PM-induced autophagy, we treated cells with α-NF or used an siRNA against AhR. Expression of LC3-ІІ induced by PM was decreased in a dose dependent manner by α-NF. Furthermore, knockdown of AhR with siAhR diminished PM-induced expression of LC3-ІІ and p62. Together, these results suggest that inhibition of the AhR decreases PM-induced autophagy. We confirmed these results using the autophagy-inhibitors BAF and 3-MA. Taken together, our results indicate that exposure to PM induces autophagy via the AhR in HaCaT keratinocytes.
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Affiliation(s)
- Hye Sung Jang
- Department of Genetic Engineering & Graduate School of Biotechnology, College of Life Sciences, Kyung Hee University, Yongin 17104, Republic of Korea
| | - Ji Eun Lee
- Department of Genetic Engineering & Graduate School of Biotechnology, College of Life Sciences, Kyung Hee University, Yongin 17104, Republic of Korea
| | - Cheol Hwan Myung
- Department of Genetic Engineering & Graduate School of Biotechnology, College of Life Sciences, Kyung Hee University, Yongin 17104, Republic of Korea
| | - Jong Il Park
- Department of Genetic Engineering & Graduate School of Biotechnology, College of Life Sciences, Kyung Hee University, Yongin 17104, Republic of Korea
| | - Chan Song Jo
- Department of Genetic Engineering & Graduate School of Biotechnology, College of Life Sciences, Kyung Hee University, Yongin 17104, Republic of Korea
| | - Jae Sung Hwang
- Department of Genetic Engineering & Graduate School of Biotechnology, College of Life Sciences, Kyung Hee University, Yongin 17104, Republic of Korea
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Mi T, Dong Y, Santhanam U, Huang N. Niacinamide and 12-hydroxystearic acid prevented benzo(a)pyrene and squalene peroxides induced hyperpigmentation in skin equivalent. Exp Dermatol 2018; 28:742-746. [PMID: 30339718 DOI: 10.1111/exd.13811] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2018] [Accepted: 10/05/2018] [Indexed: 01/10/2023]
Abstract
Skin surface is constantly exposed to environmental and secreted stressors such as UV, air pollution and peroxidized sebum. The current study aims to use reconstructed human skin equivalents to demonstrate topical stressor-induced hyperpigmentation and evaluate bioactives' potential protective effect. Given that polycyclic aromatic hydrocarbons are representative airborne particle-bound organic compounds with known relevance to pigmentation pathways, benzo(a)pyrene was selected as surrogate environmental toxin. On the other hand, squalene monohydroperoxides are well-characterized sebum peroxidation product under UV and pollutant exposure, thus are used as another representative skin stressor. With 3-day continuous exposure, 30 pmol/cm2 of benzo(a)pyrene and 3.4 nmol/cm2 of squalene monohydroperoxides induced significant viability loss, inflammatory response, and approximately 10 shades of pigmentation increase in pigmented living skin equivalents. At the same time, pretreatment and co-treatment with 12-hydroxystearic acid (12-HSA, 20 μmol/L) or niacinamide (5 mmol/L) ameliorated such stressor-induced consequences. Niacinamide was particularly effective against benzo(a)pyrene damage, probably as a substrate for important NAD+ dependent detoxification pathways, while 12-HSA was potent against squalene monohydroperoxides through barrier enhancing, anti-inflammatory, and anti-oxidative mechanisms. In summary, topical stressor-induced hyperpigmentation was achieved in vitro, with known bioactives showing protective benefits.
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Affiliation(s)
| | | | | | - Nan Huang
- Unilever R&D Shanghai, Shanghai, China
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