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Wu W, Wang X, He K, Li C, Li S. From mice to men: An assessment of preclinical model systems for the study of vitiligo. Clin Immunol 2024; 262:110171. [PMID: 38462156 DOI: 10.1016/j.clim.2024.110171] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2023] [Revised: 01/21/2024] [Accepted: 02/16/2024] [Indexed: 03/12/2024]
Abstract
Vitiligo is an autoimmune skin disease of multiple etiology, for which there is no complete cure. This chronic depigmentation is characterized by epidermal melanocyte loss, and causes disfigurement and significant psychosocial distress. Mouse models have been extensively employed to further our understanding of complex disease mechanisms in vitiligo, as well as to provide a preclinical platform for clinical interventional research on potential treatment strategies in humans. The current mouse models can be categorized into three groups: spontaneous mouse models, induced mouse models, and transgenic mice. Despite their limitations, these models allow us to understand the pathology processes of vitiligo at molecule, cell, tissue, organ, and system levels, and have been used to test prospective drugs. In this review, we comprehensively evaluate existing murine systems of vitiligo and elucidate their respective characteristics, aiming to offer a panorama for researchers to select the appropriate mouse models for their study.
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Affiliation(s)
- Wei Wu
- Department of Dermatology, Xijing Hospital, Fourth Military Medical University, No. 127 Changlexi Road, Xi'an 710032, Shaanxi, China
| | - Xinju Wang
- Department of Dermatology, Xijing Hospital, Fourth Military Medical University, No. 127 Changlexi Road, Xi'an 710032, Shaanxi, China
| | - Kaiqiao He
- Department of Dermatology, Xijing Hospital, Fourth Military Medical University, No. 127 Changlexi Road, Xi'an 710032, Shaanxi, China
| | - Chunying Li
- Department of Dermatology, Xijing Hospital, Fourth Military Medical University, No. 127 Changlexi Road, Xi'an 710032, Shaanxi, China.
| | - Shuli Li
- Department of Dermatology, Xijing Hospital, Fourth Military Medical University, No. 127 Changlexi Road, Xi'an 710032, Shaanxi, China.
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2
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Sevilla A, Grichnik J. Therapeutic modulation of KIT ligand in melanocytic disorders with implications for mast cell diseases. Exp Dermatol 2024; 33:e15091. [PMID: 38711220 DOI: 10.1111/exd.15091] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2023] [Revised: 04/18/2024] [Accepted: 04/19/2024] [Indexed: 05/08/2024]
Abstract
KIT ligand and its associated receptor KIT serve as a master regulatory system for both melanocytes and mast cells controlling survival, migration, proliferation and activation. Blockade of this pathway results in cell depletion, while overactivation leads to mastocytosis or melanoma. Expression defects are associated with pigmentary and mast cell disorders. KIT ligand regulation is complex but efficient targeting of this system would be of significant benefit to those suffering from melanocytic or mast cell disorders. Herein, we review the known associations of this pathway with cutaneous diseases and the regulators of this system both in skin and in the more well-studied germ cell system. Exogenous agents modulating this pathway will also be presented. Ultimately, we will review potential therapeutic opportunities to help our patients with melanocytic and mast cell disease processes potentially including vitiligo, hair greying, melasma, urticaria, mastocytosis and melanoma.
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Affiliation(s)
- Alec Sevilla
- Department of Dermatology, New York Medical College, New York, New York, USA
- Department of Internal Medicine, Lakeland Regional Health, Lakeland, Florida, USA
| | - James Grichnik
- Department of Dermatology and Cutaneous Surgery, Morsani College of Medicine, University of South Florida, Tampa, Florida, USA
- Department of Cutaneous Oncology, Moffitt Cancer Center, Tampa, Florida, USA
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3
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Zingariello M, Martelli F, Verachi P, Bardelli C, Gobbo F, Mazzarini M, Migliaccio AR. Novel targets to cure primary myelofibrosis from studies on Gata1 low mice. IUBMB Life 2019; 72:131-141. [PMID: 31749302 DOI: 10.1002/iub.2198] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2019] [Accepted: 10/24/2019] [Indexed: 01/06/2023]
Abstract
In 2002, we discovered that mice carrying the hypomorphic Gata1low mutation that reduces expression of the transcription factor GATA1 in megakaryocytes (Gata1low mice) develop myelofibrosis, a phenotype that recapitulates the features of primary myelofibrosis (PMF), the most severe of the Philadelphia-negative myeloproliferative neoplasms (MPNs). At that time, this discovery had a great impact on the field because mutations driving the development of PMF had yet to be discovered. Later studies identified that PMF, as the others MPNs, is associated with mutations activating the thrombopoietin/JAK2 axis raising great hope that JAK inhibitors may be effective to treat the disease. Unfortunately, ruxolitinib, the JAK1/2 inhibitor approved by FDA and EMEA for PMF, ameliorates symptoms but does not improve the natural course of the disease, and the cure of PMF is still an unmet clinical need. Although GATA1 is not mutated in PMF, reduced GATA1 content in megakaryocytes as a consequence of ribosomal deficiency is a hallmark of myelofibrosis (both in humans and mouse models) and, in fact, a driving event in the disease. Conversely, mice carrying the hypomorphic Gata1low mutation express an activated TPO/JAK2 pathway and partially respond to JAK inhibitors in a fashion similar to PMF patients (reduction of spleen size but limited improvement of the natural history of the disease). These observations cross-validated Gata1low mice as a bona fide animal model for PMF and prompted the use of this model to identify abnormalities that might be targeted to cure the disease. We will summarize here data generated in Gata1low mice indicating that the TGF-β/P-selectin axis is abnormal in PMF and represents a novel target for its treatment.
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Affiliation(s)
- Maria Zingariello
- Unit of Microscopic and Ultrastructural Anatomy, Department of Medicine, University Campus Bio-Medico, Rome, Italy
| | | | - Paola Verachi
- Department of Biological and Neurobiological Medicine, University of Bologna, Bologna, Italy
| | - Claudio Bardelli
- Department of Biological and Neurobiological Medicine, University of Bologna, Bologna, Italy
| | - Francesca Gobbo
- Department of Biological and Neurobiological Medicine, University of Bologna, Bologna, Italy
| | - Maria Mazzarini
- Department of Biological and Neurobiological Medicine, University of Bologna, Bologna, Italy
| | - Anna Rita Migliaccio
- Department of Biological and Neurobiological Medicine, University of Bologna, Bologna, Italy.,Myeloproliferative Neoplasms Research Consortium, New York, New York
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Risk of Distinctive Hair Changes Associated With Pazopanib in Patients With Renal Cell Carcinoma (RCC) Versus Patients Without RCC: A Comparative Systematic Review and Meta-analysis. Clin Genitourin Cancer 2017; 15:e325-e335. [DOI: 10.1016/j.clgc.2016.12.018] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2016] [Revised: 12/05/2016] [Accepted: 12/10/2016] [Indexed: 11/23/2022]
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5
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Liu S, Kurzrock R. Understanding Toxicities of Targeted Agents: Implications for Anti-tumor Activity and Management. Semin Oncol 2015; 42:863-75. [DOI: 10.1053/j.seminoncol.2015.09.032] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
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6
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Liu S, Kurzrock R. Toxicity of targeted therapy: Implications for response and impact of genetic polymorphisms. Cancer Treat Rev 2014; 40:883-91. [PMID: 24867380 DOI: 10.1016/j.ctrv.2014.05.003] [Citation(s) in RCA: 113] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2014] [Revised: 05/06/2014] [Accepted: 05/08/2014] [Indexed: 12/11/2022]
Abstract
Targeted therapies have unique toxicity profiles. Common adverse events include rash, diarrhea, hypertension, hypothyroidism, proteinuria, depigmentation, and hepatotoxicity. Some of these toxicities are caused by on-target, mechanism-associated effects, which can be stratified as to whether or not the targets are relevant to response. Other toxicities are off-target and may be caused by the class of agent, e.g. antibody vs small molecule tyrosine kinase inhibitor, or by immune reactions or toxic metabolites. Both on- and off-target toxicities may be due to higher drug concentrations or altered end-organ sensitivity, which in turn can be a consequence of genetic polymorphisms controlling metabolism or tissue responsiveness. On-target toxicities are important to identify as some correlate with response and, hence, amelioration of these side effects is preferable to dose reduction or stopping drug. Toxicities secondary to relevant target impact may be recognized when distinct types of agents, such as antibodies and small molecule kinase inhibitors, with the same target have a similar side effect. For example, both bevacizumab and vascular endothelial growth factor receptor (VEGFR) kinase inhibitors cause hypertension; both epidermal growth factor receptor (EGFR) antibodies and kinase inhibitors cause rash; and these toxicities correlate with response. Herein we review common targeted agent-related toxicities, relevant genetic polymorphisms, and implications for response and patient management.
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Affiliation(s)
- Sariah Liu
- Division of Hematology and Oncology and Center for Personalized Cancer Therapy, University of California San Diego Moores Cancer Center, United States.
| | - Razelle Kurzrock
- Division of Hematology and Oncology and Center for Personalized Cancer Therapy, University of California San Diego Moores Cancer Center, United States
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7
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Zeng K, Li L, Huang L, Liang YH. Newly identified phenotypes in a FIP1L1/PDGFRA-associated paediatric HES patient: thrombocytosis, mHPA, young stroke and blindness. J Eur Acad Dermatol Venereol 2014; 29:614-6. [PMID: 24576219 DOI: 10.1111/jdv.12416] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Affiliation(s)
- K Zeng
- Department of Dermatology, Nanfang Hospital, Southern Medical University, Guangzhou, China
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8
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Production of the Soluble Form of KIT, s-KIT, Abolishes Stem Cell Factor-Induced Melanogenesis in Human Melanocytes. J Invest Dermatol 2008; 128:1763-72. [DOI: 10.1038/jid.2008.9] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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9
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Adjei AA. Novel small-molecule inhibitors of the vascular endothelial growth factor receptor. Clin Lung Cancer 2007; 8 Suppl 2:S74-8. [PMID: 17382028 DOI: 10.3816/clc.2007.s.005] [Citation(s) in RCA: 5] [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
Sustained angiogenesis is one of the hallmarks of carcinogenesis. Vascular endothelial growth factor (VEGF) is a critical molecule mediating pro-angiogenic signals against which a number of therapeutic approaches have been designed. The 2 predominant approaches to inhibiting VEGF signalling are the use of monoclonal antibodies to block the receptor or ligand and small molecule receptor kinase inhibitors. There are several small-molecule inhibitors of tyrosine kinase activity of VEGF receptors in clinical trials. These are discussed in this review.
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Affiliation(s)
- Alex A Adjei
- Roswell Park Cancer Institute, Buffalo, NY 14263, USA.
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10
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Abstract
Sustained angiogenesis is one of the hallmarks of carcinogenesis. Vascular endothelial growth factor (VEGF) is a crucial molecule mediating proangiogenic signals against which a number of therapeutic approaches have been designed, such as monoclonal antibodies, small-molecule receptor kinase inhibitors, and nucleic acid inhibitors. The VEGF signaling pathway as a target in lung cancer therapy was validated by a randomized phase III study of platinum agent-based combination chemotherapy with or without bevacizumab, a recombinant humanized monoclonal antibody against VEGF-A, in first-line, nonsquamous, metastatic non-small-cell lung cancer. This trial demonstrated an improvement in overall survival among patients who received bevacizumab in comparison with those who received carboplatin and paclitaxel alone. In this review, we will discuss various aspects of this pivotal trial and highlight issues relevant to angiogenesis inhibition in the treatment of non-small-cell lung cancer.
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Affiliation(s)
- Grace K Dy
- Department of Medicine, Mayo Clinic, Rochester, MN 55905, USA
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11
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Hachiya A, Sriwiriyanont P, Kaiho E, Kitahara T, Takema Y, Tsuboi R. An In Vivo Mouse Model of Human Skin Substitute Containing Spontaneously Sorted Melanocytes Demonstrates Physiological Changes after UVB Irradiation. J Invest Dermatol 2005; 125:364-72. [PMID: 16098048 DOI: 10.1111/j.0022-202x.2005.23832.x] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Human skin substitutes (HSS) have been developed for repairing burns and other acute or chronic wounds. But although the clinical utility of HSS is well known, scant attention has been paid to their cosmetic properties, especially with regard to color compatibility with the patient's complexion. In this study, we generated an HSS from mixed cell slurries containing keratinocytes and fibroblasts with and without melanocytes on the back of severe combined immunodeficient mice by means of a spontaneous cell-sorting technique. At 16 wk after grafting, Caucasian donor-derived HSS with melanocytes were macroscopically clearly darker than those without melanocytes, and a more darkly pigmented HSS was produced when cells from donors of African descent were seeded. Immunohistochemistry of c-kit, S-100, and HMB45, as well as Fontana-Masson staining and transmission electron microscopy (TEM) demonstrated that melanocytes spontaneously localized to the basal layer. Melanosome transfer to keratinocytes was correctly reorganized, and melanin was evenly dispersed in the basal and suprabasal layers. Colorimetric analysis showed a significantly lower L-value by day 14 following irradiation with 120 mJ per cm2 ultraviolet-B (UVB) (p<0.01), whereas epidermal thickness increased by 50% 1 d after exposure (p<0.01), indicating a normal physiological response to UVB irradiation. These findings suggest that HSS with spontaneously sorted melanocytes offer a means of treating both the structural and cosmetic aspects of skin conditions and trauma, such as pigmentary disorders and skin wounds, by allowing manipulation of the color and population of donor melanocytes.
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Affiliation(s)
- Akira Hachiya
- Kao Biological Science Laboratories, Haga, Tochigi, Japan.
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Hachiya A, Kobayashi A, Ohuchi A, Takema Y, Imokawa G. The paracrine role of stem cell factor/c-kit signaling in the activation of human melanocytes in ultraviolet-B-induced pigmentation. J Invest Dermatol 2001; 116:578-86. [PMID: 11286626 DOI: 10.1046/j.1523-1747.2001.01290.x] [Citation(s) in RCA: 157] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
The interaction of stem cell factor with its receptor, c-kit, is well known to be critical to the survival of melanocytes. Little is known about the role(s) of the stem cell factor/c-kit interaction in epidermal pigmentation, however. To clarify whether the stem cell factor/c-kit signaling has a paracrine role in ultraviolet-B-induced pigmentation, we determined whether the exposure of human keratinocytes, melanocytes, and the epidermis to ultraviolet B light stimulates the expression of stem cell factor or c-kit at the gene and/or protein levels. We further examined whether interrupting the binding of stem cell factor to c-kit by subepidermal injection of a monoclonal antibody to c-kit affects ultraviolet-B-induced pigmentation in brownish guinea pig skin. When human keratinocytes and melanocytes in culture were exposed to ultraviolet B light, transcripts of stem cell factor and c-kit (as assessed by reverse transcription polymerase chain reaction) and expression of those proteins (by enzyme-linked immunosorbent assay and western blotting) increased significantly and peaked at a dose of 20-40 mJ per cm2. In ultraviolet-B-exposed human epidermis, stem cell factor transcripts and protein expression were also markedly enhanced compared with the nonexposed epidermis. Immunohistochemistry with antibodies to stem cell factor revealed an increased staining in the ultraviolet-B-exposed epidermis, which was accompanied by a slight epidermal hyperplasia. In the course of ultraviolet-B-induced pigmentation of brownish guinea pig skin, the subepidermal injection of c-kit inhibitory antibodies completely abolished the induction of pigmentation in the ultraviolet-B-exposed area, and there was no increase in the number of dihydroxyphenylalanine-positive melanocytes. These findings indicate that the stem cell factor/c-kit signaling is critically involved in the biologic mechanism of ultraviolet-B-induced pigmentation.
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Affiliation(s)
- A Hachiya
- Kao Biological Science Laboratories, Haga, Tochigi, Japan
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Halaban R, Svedine S, Cheng E, Smicun Y, Aron R, Hebert DN. Endoplasmic reticulum retention is a common defect associated with tyrosinase-negative albinism. Proc Natl Acad Sci U S A 2000; 97:5889-94. [PMID: 10823941 PMCID: PMC18529 DOI: 10.1073/pnas.97.11.5889] [Citation(s) in RCA: 145] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Tyrosinase is a melanocyte-specific enzyme critical for the synthesis of melanin, a process normally restricted to a post-Golgi compartment termed the melanosome. Loss-of-function mutations in tyrosinase are the cause of oculocutaneous albinism, demonstrating the importance of the enzyme in pigmentation. In the present study, we explored the possibility that trafficking of albino tyrosinase from the endoplasmic reticulum (ER) to the Golgi apparatus and beyond is disrupted. Toward this end, we analyzed the common albino mouse mutation Tyr(C85S), the frequent human albino substitution TYR(T373K), and the temperature-sensitive tyrosinase TYR(R402Q)/Tyr(H402A) found in humans and mice, respectively. Intracellular localization was monitored in albino melanocytes carrying the native mutation, as well as in melanocytes ectopically expressing green fluorescent protein-tagged tyrosinase. Enzymatic characterization of complex glycans and immunofluorescence colocalization with organelle-specific resident proteins established that all four mutations produced defective proteins that were retained in the ER. TYR(R402Q)/Tyr(H402A) Golgi processing and transport to melanosomes were promoted at the permissive temperature of 32 degrees C, but not at the nonpermissive 37 degrees C temperature. Furthermore, evidence of protein misfolding was demonstrated by the prolonged association of tyrosinase mutants with calnexin and calreticulin, known ER chaperones that play a key role in the quality-control processes of the secretory pathway. From these results we concluded that albinism, at least in part, is an ER retention disease.
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Affiliation(s)
- R Halaban
- Department of Dermatology, Yale University School of Medicine, New Haven, CT 06520, USA.
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Ota A, Park JS, Jimbow K. Functional regulation of tyrosinase and LAMP gene family of melanogenesis and cell death in immortal murine melanocytes after repeated exposure to ultraviolet B. Br J Dermatol 1998; 139:207-15. [PMID: 9767233 DOI: 10.1046/j.1365-2133.1998.02356.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
This study characterizes the induction of melanogenesis and the expression of tyrosinase, tyrosinase-related protein (TRP) and lysosome-associated membrane protein (LAMP) gene families in the cultured melanocyte lines of non-agouti mice with four major genetic loci, i.e. melan-a2 (black, wild type), melan-b (brown, TRP-1 mutation), melan-s (black, piebaldism mutation) and melan-c (white, tyrosinase mutation) in response to repeated exposure to ultraviolet (UV) B (5 mJ/cm2, 7 consecutive days). Electron microscopy showed that new melanogenesis was induced in melan-a2, melan-s and melan-b melanocytes. Melan-a2, melan-s and melan-b showed an almost twofold increase in tyrosinase activity and gene expression with increased synthesis of melanosomes, although melan-b showed a minimum increase in tyrosinase activity. There was a twofold upregulation of LAMP-1 mRNA but no alteration in LAMP-2 and LAMP-3 mRNA expression in melan-a2, while there was no alteration in LAMP-1 mRNA expression but increased expression of LAMP-2 and LAMP-3 mRNA in melan-s, LAMP-3 showing a higher increase. Melan-b cells showed the same gene expression of LAMP-1, LAMP-2 and LAMP-3 as that of non-UV exposed cells. All three lines, however, exhibited simultaneously cell death, melan-b reaching the highest rate of cell death (96.5%). In contrast, melan-c, which did not have any tyrosinase activity with failure of melanogenesis induction, expressed all the mRNAs of the tyrosinase and LAMP gene families, but was not associated with any significant melanocyte death. Our study indicated: (i) that melanogenesis induction and melanocyte death are two photobiological processes occurring simultaneously after repeated UVB exposure, (ii) that in response to an upregulation of tyrosinase mRNA and enzymic activity, there was a co-ordinated upregulation of the LAMP-1 gene in wild type melan-a2, while no upregulation was found in melan-s and melan-b mutants, and (iii) that UV-induced melanocyte death is related to the upregulation of the tyrosinase gene, induction of new melanogenesis and mutation of the TRP-1 gene in immortal murine melanocytes.
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Affiliation(s)
- A Ota
- Dermatology and Cutaneous Sciences, Faculty of Medicine, University of Alberta, Edmonton, Canada
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Grichnik JM, Burch JA, Burchette J, Shea CR. The SCF/KIT pathway plays a critical role in the control of normal human melanocyte homeostasis. J Invest Dermatol 1998; 111:233-8. [PMID: 9699723 DOI: 10.1046/j.1523-1747.1998.00272.x] [Citation(s) in RCA: 160] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
During development, the interaction of stem cell factor (SCF) with its receptor, KIT, is critical for the survival of melanocytes. Limited in vivo human studies have suggested a possible activating role of SCF on adult human melanocytes. In order to study the impact of this pathway on normal melanocyte homeostasis, human skin xenografts were treated with serial injections of recombinant human SCF or a KIT-inhibitory antibody (K44.2). On histologic evaluation, SCF injection increased, whereas KIT inhibition decreased the number, size, and dendricity of melanocytes. Immunohistochemical expression of melanocyte differentiation antigens, including tyrosinase-related-protein-1 and gp100/pmel17, was markedly increased by treatment with SCF, and decreased by K44.2 treatment. The number of Ki67-positive melanocytes was increased in the SCF-treated tissue, suggesting a direct proliferative effect of SCF; conversely, treatment with K44.2 resulted in melanocyte loss, which did not appear reversible with prolonged treatment. These findings demonstrate that the SCF/KIT pathway remains critical in adult human skin, and that pharmacologic modulation of this single pathway can control cutaneous melanocyte homeostasis.
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Affiliation(s)
- J M Grichnik
- Department of Medicine, Duke University Medical Center, Durham, North Carolina 27710, USA
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16
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Smith R, Healy E, Siddiqui S, Flanagan N, Steijlen PM, Rosdahl I, Jacques JP, Rogers S, Turner R, Jackson IJ, Birch-Machin MA, Rees JL. Melanocortin 1 receptor variants in an Irish population. J Invest Dermatol 1998; 111:119-22. [PMID: 9665397 DOI: 10.1046/j.1523-1747.1998.00252.x] [Citation(s) in RCA: 170] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The identification of an association between variants in the human melanocortin 1 receptor (MC1R) gene and red hair and fair skin, as well as the relation between variants of this gene and coat color in animals, suggests that the MC1R is an integral control point in the normal pigmentation phenotype. In order to further define the contribution of MC1R variants to pigmentation in a normal population, we have looked for alterations in this gene in series of individuals from a general Irish population, in whom there is a preponderance of individuals with fair skin type. Seventy-five per cent contained a variant in the MC1R gene, with 30% containing two variants. The Arg151Cys, Arg160Trp, and Asp294His variants were significantly associated with red hair (p = 0.0015, p < 0.001, and p < 0.005, respectively). Importantly, no individuals harboring two of these three variants did not have red hair, although some red-haired individuals only showed one alteration. The same three variants were also over-represented in individuals with light skin type as assessed using a modified Fitzpatrick scale. Despite these associations many subjects with dark hair/darker skin type harbored MC1R variants, but there was no evidence of any particular association of variants with the darker phenotype. The Asp294His variant was similarly associated with red hair in a Dutch population, but was infrequent in red-headed subjects from Sweden. The Asp294His variant was also significantly associated with nonmelanoma skin cancer in a U.K. population. The results show that the Arg151Cys, Arg160Trp, and Asp294His variants are of key significance in determining the pigmentary phenotype and response to ultraviolet radiation, and suggest that in many cases the red-haired component and in some cases fair skin type are inherited as a Mendelian recessive.
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Affiliation(s)
- R Smith
- Department of Dermatology, University of Newcastle upon Tyne, UK
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Abstract
The destruction of melanocytes is the cause of depigmented maculae that clinically represent the disease vitiligo. Although the cause is unknown, various theories such as the autoimmune, autocytotoxic, and neural hypotheses have been proposed. Extensive research has provided numerous answers regarding the pathogenesis, histopathologic evidence, and treatment of vitiligo. This discussion of vitiligo summarizes the varied clinical presentations of the disease, theories attempting to explain the mechanism of melanocyte destruction, histopathologic findings, and different treatment modalities currently available.
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Affiliation(s)
- S O Kovacs
- Department of Dermatology, Barnes Hospital, St. Louis, Missouri, USA
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Reid K, Turnley AM, Maxwell GD, Kurihara Y, Kurihara H, Bartlett PF, Murphy M. Multiple roles for endothelin in melanocyte development: regulation of progenitor number and stimulation of differentiation. Development 1996; 122:3911-9. [PMID: 9012511 DOI: 10.1242/dev.122.12.3911] [Citation(s) in RCA: 106] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Melanocytes in the skin are derived from the embryonic neural crest. Recently, mutations in endothelin 3 and the endothelin receptor B genes have been shown to result in gross pigment defects, indicating that this signalling pathway is required for melanocyte development. We have examined the effects of endothelins on melanocyte progenitors in cultures of mouse neural crest. Firstly, they stimulate an increase in progenitor number and act synergistically with another factor, Steel factor, in the survival and proliferation of the progenitors. These findings are consistent with findings from mice with natural mutations in the endothelin receptor B gene, which show an early loss of melanocyte progenitors. Secondly, endothelins induce differentiation of the progenitors into fully mature pigmented melanocytes. This finding is consistent with the expression of endothelins in the skin of mice at the initiation of pigmentation. The melanocytes generated in endothelin-treated cultures also become responsive to alpha melanocyte-stimulating hormone, which then acts to regulate the activity of the pigmentation pathway. These findings indicate two key roles for endothelin in melanocyte development: regulation of expansion of the progenitor pool and differentiation of progenitors into mature melanocytes.
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Affiliation(s)
- K Reid
- The Walter and Eliza Hall Institute of Medical Research, Royal Melbourne Hospital, Parkville, Victoria, Australia
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Kapur RP, Sweetser DA, Doggett B, Siebert JR, Palmiter RD. Intercellular signals downstream of endothelin receptor-B mediate colonization of the large intestine by enteric neuroblasts. Development 1995; 121:3787-95. [PMID: 8582288 DOI: 10.1242/dev.121.11.3787] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Mice homozygous for the piebald lethal (sl) mutation, which have a complete deletion of endothelin receptor-B, fail to form ganglion cells in the distal large intestine and are nearly devoid of cutaneous melanocytes. These phenotypic features stem from incomplete colonization of the hindgut and skin by neural crest-derived neuroblasts and melanoblasts, respectively. We have used expression of a transgene, dopamine-beta-hydroxylase-nlacZ, to study colonization of the enteric nervous system in sl/sl embryos and sl/sl <--> wild-type chimeric mice. Enteric neuroblasts derived from the vagal neural crest colonize the developing foregut, midgut and distal small intestine of sl/sl embryos in a cranial-to-caudal manner indistinguishable from sl/+ or +/+ embryos. However, colonization of the large intestine is retarded and the distal large intestine is never colonized, a developmental defect identical to that observed in lethal spotted (endothelin-3 deficient) embryos. The coat pigmentation and relative distributions of mutant and wild-type ganglion cells in sl/sl <--> wild-type chimeras indicate that the defect associated with endothelin receptor-B gene deletion is not strictly neuroblast autonomous (independent of environmental factors). Instead, intercellular interactions downstream of the endothelin receptor-B mediate complete colonization of the skin and gut by neural crest cells.
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Affiliation(s)
- R P Kapur
- Department of Pathology, Children's Hospital, Seattle, Washington, USA
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