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Hart PH, Norval M. The Multiple Roles of Urocanic Acid in Health and Disease. J Invest Dermatol 2021; 141:496-502. [DOI: 10.1016/j.jid.2020.07.017] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2020] [Revised: 07/15/2020] [Accepted: 07/30/2020] [Indexed: 12/31/2022]
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Fajuyigbe D, Young AR. The impact of skin colour on human photobiological responses. Pigment Cell Melanoma Res 2016; 29:607-618. [PMID: 27454804 PMCID: PMC5132026 DOI: 10.1111/pcmr.12511] [Citation(s) in RCA: 68] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2016] [Accepted: 07/11/2016] [Indexed: 01/30/2023]
Abstract
Terrestrial solar ultraviolet radiation (UVR) exerts both beneficial and adverse effects on human skin. Epidemiological studies show a lower incidence of skin cancer in people with pigmented skins compared to fair skins. This is attributed to photoprotection by epidermal melanin, as is the poorer vitamin D status of those with darker skins. We summarize a wide range of photobiological responses across different skin colours including DNA damage and immunosuppression. Some studies show the generally modest photoprotective properties of melanin, but others show little or no effect. DNA photodamage initiates non‐melanoma skin cancer and is reduced by a factor of about 3 in pigmented skin compared with white skin. This suggests that if such a modest reduction in DNA damage can result in the significantly lower skin cancer incidence in black skin, the use of sunscreen protection might be extremely beneficial for susceptible population. Many contradictory results may be explained by protocol differences, including differences in UVR spectra and exposure protocols. We recommend that skin type comparisons be done with solar‐simulated radiation and standard erythema doses or physical doses (J/m2) rather than those based solely on clinical endpoints such as minimal erythema dose (MED).
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Affiliation(s)
- Damilola Fajuyigbe
- Division of Genetics and Molecular Medicine, Faculty of Life Sciences and Medicine, St John's Institute of Dermatology, King's College London, London, UK
| | - Antony R Young
- Division of Genetics and Molecular Medicine, Faculty of Life Sciences and Medicine, St John's Institute of Dermatology, King's College London, London, UK
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Decara JM, Aguilera J, Abdala R, Sánchez P, Figueroa FL, Herrera E. Screening of urocanic acid isomers in human basal and squamous cell carcinoma tumors compared with tumor periphery and healthy skin. Exp Dermatol 2008; 17:806-12. [DOI: 10.1111/j.1600-0625.2008.00695.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Gibbs NK, Tye J, Norval M. Recent advances in urocanic acid photochemistry, photobiology and photoimmunology. Photochem Photobiol Sci 2008; 7:655-67. [PMID: 18528548 DOI: 10.1039/b717398a] [Citation(s) in RCA: 105] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Urocanic acid (UCA), produced in the upper layers of mammalian skin, is a major absorber of ultraviolet radiation (UVR). Originally thought to be a 'natural sunscreen', studies conducted a quarter of a century ago proposed that UCA may be a chromophore for the immunosuppression that follows exposure to UVR. With its intriguing photochemistry, its role in immunosuppression and skin cancer development, and skin barrier function, UCA continues to be the subject of intense research effort. This review summarises the photochemical, photobiological and photoimmunological findings regarding UCA, published since 1998.
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Affiliation(s)
- Neil K Gibbs
- Dermatological Sciences, University of Manchester Medical School, Stopford Building, Oxford Road, Manchester, UK M13 9PT.
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Norval M, McLoone P, Lesiak A, Narbutt J. The Effect of Chronic Ultraviolet Radiation on the Human Immune System†. Photochem Photobiol 2007; 84:19-28. [DOI: 10.1111/j.1751-1097.2007.00239.x] [Citation(s) in RCA: 83] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
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de Gruijl FR, Longstreth J, Norval M, Cullen AP, Slaper H, Kripke ML, Takizawa Y, van der Leun JC. Health effects from stratospheric ozone depletion and interactions with climate change. Photochem Photobiol Sci 2003; 2:16-28. [PMID: 12659536 DOI: 10.1039/b211156j] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The potential health effects of elevated levels of ambient UV-B radiation are diverse, and it is difficult to quantify the risks, especially as they are likely to be considerably modified by human behaviour. Nevertheless epidemiological and experimental studies have confirmed that UV radiation is a definite risk factor for certain types of cataract, with peak efficacy in the UV-B waveband. The causal link between squamous cell carcinoma and cumulative solar UV exposure has been well established. New findings regarding the genetic basis of skin cancer, including studies on genetically modified mice, have confirmed the epidemiological evidence that UV radiation contributes to the formation of basal cell carcinomas and cutaneous melanomas, For the latter, animal models have demonstrated that UV exposure at a very young age is more detrimental than exposure in adulthood. Although suppression of certain immune responses has been recognised following UV exposure, the impact of this suppression on the control of infectious and autoimmune diseases is largely unknown. However, studies on several microbial infections have indicated significant consequences in terms of symptoms or reactivation of disease. The possibility that the immune response to vaccination could be depressed by UV-B exposure is of considerable concern. Newly emerging possibilities regarding interactions between ozone depletion and global climate change further complicate the risk assessments for human health but might result in an increased incidence of cataracts and skin cancer, plus alterations in the patterns of certain categories of infectious and other diseases.
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Affiliation(s)
- Frank R de Gruijl
- Leiden University Medical Centre, Sylvius Lab., Wassenaarseweg 72, NL-2333 AL Leiden, The Netherlands
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Abstract
Exposure to ultraviolet (UV) radiation, particularly the UVB wavelengths, leads not only to DNA damage but also to suppression of cell-mediated immunity to antigens encountered shortly after the irradiation. One initiator of this complex process is cis-urocanic acid (cis-UCA), which is formed from the naturally occurring trans isomer in the epidermis on absorption of UV. cis-UCA has been shown to have immunomodulating properties in a variety of in vivo and in vitro experimental systems, although its mechanism of action is not yet clear. This article covers methods of preparing cis-UCA and of analyzing UCA isomers in various human and mouse tissues. Experiments that demonstrate that cis-UCA is immunosuppressive are described. The final section deals with the preparation and characterization of a monoclonal antibody with specificity for cis-UCA.
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Affiliation(s)
- Mary Norval
- Medical Microbiology, University of Edinburgh Medical School, Scotland, UK.
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Abstract
Ultraviolet (UV) radiation induces a specific tolerance toward UV-induced skin tumors. This phenomenon has been known and studied for more than 25 years, but the mechanisms by which protective tumor immunity or tumor tolerance is induced are still largely obscure. In parallel with these studies, short-term assays on UV-induced immunosuppression and tolerance toward simple chemicals (e.g., dinitrochlorobenzene) have been analyzed, particularly with respect to the role of cytokines (most notably, interleukin (IL)-10 vs IL-12). However, these short-term assays are not likely to be fully adequate models of the long-term UV-induced tumor tolerance. The important nodal points of action in these immune reactions appear to be the T cells and the antigen-presenting cells (APCs) that prime them. The main focus should probably be on CD8(+) T cells as the ultimate effector of the cytotoxic response against UV-induced skin cancers. APC-mediated activation of these cells depends strongly on cosignaling of CD4(+) T cells. In a tumor tolerant state the activity of the cytotoxic CD8(+) T cells appears to be inhibited through CTLA-4(+) and natural killer T cells. The latter cells are CD1-restricted, which indicates the importance of "unconventional" antigens to UV-induced tumor tolerance.
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Affiliation(s)
- Frank R de Gruijl
- Department of Dermatology, Leiden University Medical Center/LUMC, Sylvius Laboratories, Room 3038, Wassenaarseweg 72, NL-2333 AL Leiden, The Netherlands.
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Grimbaldeston MA, Skov L, Finlay-Jones JJ, Hart PH. Increased dermal mast cell prevalence and susceptibility to development of basal cell carcinoma in humans. Methods 2002; 28:90-6. [PMID: 12231192 DOI: 10.1016/s1046-2023(02)00213-x] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Exposure to ultraviolet B (UVB) radiation (280-320 nm) is the primary etiologic factor associated with the development of basal cell carcinoma (BCC). The outgrowth of these keratinocyte-derived skin lesions is enhanced by the ability of UVB to impair an immune response that would otherwise eliminate them. Studies in a range of inbred mouse strains as well as mast cell-depleted mice reconstituted with mast cell precursors support a functional link between histamine-staining dermal mast cells and the extent of susceptibility to UVB-induced systemic immunomodulation. Humans, like mouse strains, display variations in dermal mast cell prevalence. In a study of Danish and South Australian BCC patients and control subjects, one 4-mm punch biopsy of non-sun-exposed buttock skin was sampled from each participant. This skin site was investigated to avoid any changes in mast cell prevalence caused by sun exposure. Two sections (4 microm) per biopsy were immunohistochemically stained for detection of histamine-containing dermal mast cells. Computer-generated image analysis evaluated dermal mast cell prevalence in both sections by quantifying the total number of mast cells according to the total dermal area (expressed as mast cells per square millimeter). This technique enabled us to detect heterogeneity of dermal mast cell prevalence in buttock skin between individuals and provided evidence of an association between high dermal mast cell prevalence and BCC development in two diverse populations. We hypothesize that mast cells function in humans, as in mouse strains, by initiating immunosuppression following UV irradiation and, thereby, allowing a permissive environment for the development of BCC. Thus, a high dermal mast cell prevalence as demonstrable in buttock skin is a significant predisposing factor for development of BCC in humans.
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Affiliation(s)
- Michele A Grimbaldeston
- Department of Microbiology and Infectious Diseases, School of Medicine, Flinders University, Adelaide, Australia.
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Norval M. Effects of solar radiation on the human immune system. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY. B, BIOLOGY 2001; 63:28-40. [PMID: 11684449 DOI: 10.1016/s1011-1344(01)00200-7] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
On UV irradiation of the skin, a complex cascade of immunological changes results, initiated by cutaneous chromophores and ending in suppression of some local and systemic immune responses. In this review, the stages in this process are outlined first, concentrating on the roles of DNA and urocanic acid as photoreceptors. Evidence indicating UV-induced immunomodulation of delayed hypersensitivity and resistance to infectious diseases in human subjects follows. Aspects of genetic susceptibility to the immunosuppressive effects of UV exposure and extrapolation of the data obtained in animal models to the human situation are included. Finally uncertain and unknown factors relating to the impact of UV on the human immune system are discussed.
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Affiliation(s)
- M Norval
- Department of Medical Microbiology, University of Edinburgh Medical School, Teviot Place, Edinburgh EH8 9AG, Scotland, UK.
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De Simone C, Masini C, Cattaruzza MS, Guerriero C, Cerimele D, Norval M. Urocanic acid isomers in patients with non-melanoma skin cancer. Br J Dermatol 2001; 144:858-61. [PMID: 11298549 DOI: 10.1046/j.1365-2133.2001.04145.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
BACKGROUND Cis-urocanic acid (cis-UCA), formed from the naturally occurring trans-isomer in the epidermis on ultraviolet (UV) radiation, initiates some of the changes leading to UV-induced immunosuppression, but its role in cutaneous carcinogenesis has not been fully investigated. OBJECTIVES To measure the concentration of UCA isomers in the photoexposed and non-photoexposed skin of patients with multiple non-melanoma skin cancer (NMSC), enrolled in different periods of the year, in comparison with control subjects. PATIENTS/METHODS UCA isomers were determined by high-performance liquid chromatography analysis in samples from the outer arm (photoexposed site) and buttock (non-photoexposed site) obtained from 20 patients and 19 controls during the winter period (October to April), and from five patients and 11 controls during the summer period (June to September). RESULTS In the winter months, no difference was found between patients and controls in the concentration of UCA or the percentage of cis-UCA in either site. In the summer months, the percentage of cis-UCA in the buttock of patients and controls was similar but it was significantly higher in the arm of the controls (42%) than in the patients (17%). CONCLUSIONS We conclude that different behaviour regarding sun exposure is the most likely explanation for these results, and that the concentration of UCA and its isomers does not reflect a tendency for individuals to develop NMSC.
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Affiliation(s)
- C De Simone
- Department of Dermatology, Universita Cattolica S. Cuore, L.go A. Gemelli, 8-00168 Roma, Italy.
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Effects of solar radiation on the human immune system. COMPREHENSIVE SERIES IN PHOTOSCIENCES 2001. [DOI: 10.1016/s1568-461x(01)80040-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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Hart PH, Grimbaldeston MA, Finlay-Jones JJ. Sunlight, immunosuppression and skin cancer: role of histamine and mast cells. Clin Exp Pharmacol Physiol 2001; 28:1-8. [PMID: 11153522 DOI: 10.1046/j.1440-1681.2001.03392.x] [Citation(s) in RCA: 66] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
1. The development into tumours of skin cells transformed by ultraviolet (UV) B radiation of wavelengths 290-320 nm is enhanced by the ability of UVB to suppress an immune response that would otherwise destroy them. Ultraviolet B-induced immunomodulation may be by multiple mechanisms, but generally manifests in an antigen-presenting cell defect and an altered cytokine environment in the draining lymph nodes. 2. Immune responses to microbial or self-antigens may be dysfunctional by similar mechanisms following UVB exposure. 3. Earliest-acting intermediates in the initiation of UVB-induced immunosuppression are the UVB absorbers (photoreceptors) of the skin, notably DNA resulting in immunoregulatory cytokine production, and trans-urocanic acid (UCA), which, upon isomerization to its cis isomer, signals downstream immunosuppressive events. 4. In mice, dermal mast cells are critical to UVB-induced systemic immunomodulation. In mice, there is a functional link as well as a linear relationship between the prevalence of histamine-staining dermal mast cells and the log of the dose of UVB required for 50% immunosuppression. Studies with histamine receptor antagonists support histamine as the main' product of mast cells involved. Histamine acts in large part via a prostanoid-dependent pathway. 5. Approximately 50% of humans and greater than 90% of patients with non-melanoma skin cancer are UVB susceptible for suppression of a contact hypersensitivity response. Neither cytokine polymorphisms nor UVB-induced levels of cis-UCA in irradiated skin have been linked to UVB susceptibility. Patients with basal cell carcinomas (BCC) have an increased dermal mast cell prevalence in non-sun-exposed buttock skin. We propose that mast cells function in humans, as in mice, by initiating immunosuppression and, thereby, allowing a permissive environment for BCC development.
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Affiliation(s)
- P H Hart
- Department of Microbiology and Infectious Diseases, School of Medicine, Flinders University, Adelaide, South Australia, Australia.
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Grimbaldeston MA, Skov L, Baadsgaard O, Skov BG, Marshman G, Finlay-Jones JJ, Hart PH. Communications: high dermal mast cell prevalence is a predisposing factor for basal cell carcinoma in humans. J Invest Dermatol 2000; 115:317-20. [PMID: 10951253 DOI: 10.1046/j.1523-1747.2000.00050.x] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Ultraviolet B radiation (280-320 nm) can initiate skin cancer as well as suppress the immune system, thereby preventing the rejection of ultraviolet-B-induced tumors. Recently we reported that there was not only a correlation but also a functional link between dermal mast cell prevalence and susceptibility to ultraviolet-B-induced systemic immunosuppression in multiple strains of mice. In this study, we investigated whether increased dermal mast cell prevalence is a significant predisposing factor for basal cell carcinoma development in humans. In 21 Danes with a history of basal cell carcinoma and 20 control subjects of similar age, sex, skin phototype, and recreational sun exposure over the past 12 mo, dermal mast cell prevalence was quantified on non-sun-exposed buttock skin. We investigated this skin site in order to avoid any changes in mast cell prevalence caused by sun exposure and assumed that the prevalence of mast cells in buttock skin correlated with that at sun-exposed sites at critical times in the development of basal cell carcinomas. Patients with a history of basal cell carcinoma had a significantly higher median dermal mast cell prevalence than control subjects (p = 0.01, Mann-Whitney U ). No correlation was observed between dermal mast cell prevalence and age of basal cell carcinoma patients and control subjects. These results suggest that increased dermal mast cell prevalence is a predisposing factor for basal cell carcinoma development in humans. We hypothesize that mast cells function in humans, as in mice, by initiating immunosuppression and thereby allowing a permissive environment for basal cell carcinoma development.
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Affiliation(s)
- M A Grimbaldeston
- Department of Microbiology and Infectious Diseases, School of Medicine, Flinders University, Adelaide, Australia.
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Abstract
The adverse outcome of increased ultraviolet (UV) irradiation on human health is currently of concern. While many experiments have been carried out in rodent models, fewer have been designed to test the effects of UV exposure in human subjects. This review concentrates on the modulations induced in the human immune system by UV, and outlines changes in antigen presentation by Langerhans cells and macrophages, in the activities of natural killer cells and T cells, and in cytokine regulation. Precautionary measures which might be taken to help protect people against the immunosuppressive action of UV irradiation are considered.
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Affiliation(s)
- M S Duthie
- Department of Medical Microbiology, University of Edinburgh Medical School, Teviot Place, Edinburgh EH8 9AG, U.K
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