1
|
Abdou AG, Farag AGA, Rashwan M, Shehata WA. The clinical and pathological effectiveness of microneedling and topical 5-fluorouracil in vitiligo treatment: An association with matrix metalloproteinase 2 immunohistochemical expression. J Cosmet Dermatol 2021; 21:2153-2161. [PMID: 34416072 DOI: 10.1111/jocd.14388] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2021] [Revised: 07/29/2021] [Accepted: 08/03/2021] [Indexed: 11/29/2022]
Abstract
BACKGROUND The current therapies for vitiligo require long duration with often disappointing outcomes. 5-Fluorouracil (5-FU) is a chemotherapeutic agent approved for topical use in the treatment of several dermatologic conditions. Matrix metalloproteinase 2 (MMP2) is synthesized by keratinocytes during the epidermal remodeling process and has been found to help in melanocyte migration. AIM To investigate the efficacy and safety of flexible microneedling followed by application of 5-FU in vitiligo treatment and to evaluate the immunohistochemical expression of MMP2 in involved skin in vitiligo patients before and after treatment. METHODS Twenty patients presented with vitiligo were planned to receive one session every 2 weeks for 12 weeks of microneedling followed by 5-FU application. Clinical response to therapy was evaluated by VASI score. Pre- and post-treatment biopsies were taken from vitiliginous patches for MMP2 immunostaining. RESULTS Fifteen patients (75%) responded to therapy with observed side effects such as pain, erythema, and hyperpigmentation of margins. The clinical response was more in young patients and those who have short disease duration. MMP2 was significantly increased in post-treatment biopsy compared with the pretreatment one. CONCLUSIONS 5-Fluorouracil application after microneedling is effective in the treatment of vitiligo with 75% response, 60% patient satisfaction, and tolerable side effects. The improvement in vitiligo patients by microneedling and 5-fluorouracil could be due to upregulation of MMP2 in affected vitiligo specimens.
Collapse
Affiliation(s)
- Asmaa Gaber Abdou
- Pathology Department, Faculty of Medicine, Menoufia University, Shebein Elkom, Egypt
| | - Azza Gaber Antar Farag
- Dermatology, Andrology and STDs Department, Faculty of Medicine, Menoufia University, Shebein Elkom, Egypt
| | - Manal Rashwan
- Dermatology, Andrology and STDs Department, Faculty of Medicine, Menoufia University, Shebein Elkom, Egypt
| | - Wafaa Ahmed Shehata
- Dermatology, Andrology and STDs Department, Faculty of Medicine, Menoufia University, Shebein Elkom, Egypt
| |
Collapse
|
2
|
Laminin-511-E8 promotes efficient in vitro expansion of human limbal melanocytes. Sci Rep 2020; 10:11074. [PMID: 32632213 PMCID: PMC7338389 DOI: 10.1038/s41598-020-68120-0] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2020] [Accepted: 06/18/2020] [Indexed: 01/08/2023] Open
Abstract
Limbal melanocytes, located in the basal epithelial layer of the corneoscleral limbus, represent essential components of the corneal epithelial stem cell niche, but, due to difficulties in their isolation and cultivation, their biological roles and potential for stem cell-based tissue engineering approaches have not been comprehensively studied. Here, we established a protocol for the efficient isolation and cultivation of pure populations of human limbal melanocytes, which could be expanded at high yield by using recombinant laminin (LN)-511-E8 as culture substrate. Co-cultivation of limbal melanocytes with limbal epithelial stem/progenitor cells on fibrin hydrogels pre-incubated with LN-511-E8 resulted in multilayered stratified epithelial constructs within ten days. By reproducing physiological cell–cell and cell–matrix interactions of the native niche environment, these biomimetic co-culture systems provide a promising experimental model for investigating the functional roles of melanocytes in the limbal stem cell niche and their suitability for developing advanced epithelial grafts for ocular surface surface reconstruction.
Collapse
|
3
|
Dual role of laminin‑511 in regulating melanocyte migration and differentiation. Matrix Biol 2019; 80:59-71. [DOI: 10.1016/j.matbio.2018.09.006] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2018] [Revised: 09/25/2018] [Accepted: 09/25/2018] [Indexed: 11/22/2022]
|
4
|
Crawford M, Leclerc V, Dagnino L. A reporter mouse model for in vivo tracing and in vitro molecular studies of melanocytic lineage cells and their diseases. Biol Open 2017. [PMID: 28642245 PMCID: PMC5576081 DOI: 10.1242/bio.025833] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Alterations in melanocytic lineage cells give rise to a plethora of distinct human diseases, including neurocristopathies, cutaneous pigmentation disorders, loss of vision and hearing, and melanoma. Understanding the ontogeny and biology of melanocytic cells, as well as how they interact with their surrounding environment, are key steps in the development of therapies for diseases that involve this cell lineage. Efforts to culture and characterize primary melanocytes from normal or genetically engineered mouse models have at times yielded contrasting observations. This is due, in part, to differences in the conditions used to isolate, purify and culture these cells in individual studies. By breeding ROSAmT/mG and Tyr::CreERT2 mice, we generated animals in which melanocytic lineage cells are identified through expression of green fluorescent protein. We also used defined conditions to systematically investigate the proliferation and migration responses of primary melanocytes on various extracellular matrix (ECM) substrates. Under our culture conditions, mouse melanocytes exhibit doubling times in the range of 10 days, and retain exponential proliferative capacity for 50-60 days. In culture, these melanocytes showed distinct responses to different ECM substrates. Specifically, laminin-332 promoted cell spreading, formation of dendrites, random motility and directional migration. In contrast, low or intermediate concentrations of collagen I promoted adhesion and acquisition of a bipolar morphology, and interfered with melanocyte forward movements. Our systematic evaluation of primary melanocyte responses emphasizes the importance of clearly defining culture conditions for these cells. This, in turn, is essential for the interpretation of melanocyte responses to extracellular cues and to understand the molecular basis of disorders involving the melanocytic cell lineage.
Collapse
Affiliation(s)
- Melissa Crawford
- Dept. of Physiology and Pharmacology, Children's Health Research Institute and Lawson Health Research Institute, The University of Western Ontario, London, Ontario N6A 5C1, Canada
| | - Valerie Leclerc
- Dept. of Physiology and Pharmacology, Children's Health Research Institute and Lawson Health Research Institute, The University of Western Ontario, London, Ontario N6A 5C1, Canada
| | - Lina Dagnino
- Dept. of Physiology and Pharmacology, Children's Health Research Institute and Lawson Health Research Institute, The University of Western Ontario, London, Ontario N6A 5C1, Canada
| |
Collapse
|
5
|
Chung H, Jung H, Lee JH, Oh HY, Kim OB, Han IO, Oh ES. Keratinocyte-derived laminin-332 protein promotes melanin synthesis via regulation of tyrosine uptake. J Biol Chem 2014; 289:21751-9. [PMID: 24951591 PMCID: PMC4118133 DOI: 10.1074/jbc.m113.541177] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2013] [Revised: 06/09/2014] [Indexed: 11/06/2022] Open
Abstract
Melanocytes, which produce the pigment melanin, are known to be closely regulated by neighboring keratinocytes. However, how keratinocytes regulate melanin production is unclear. Here we report that melanin production in melanoma cells (B16F10 and MNT-1) was increased markedly on a keratinocyte-derived extracellular matrix compared with a melanoma cell-derived extracellular matrix. siRNA-mediated reduction of keratinocyte-derived laminin-332 expression decreased melanin synthesis in melanoma cells, and laminin-332, but not fibronectin, enhanced melanin content and α-melanocyte-stimulating hormone-regulated melanin production in melanoma cells. Similar effects were observed in human melanocytes. Interestingly, however, laminin-332 did not affect the expression or activity of tyrosinase. Instead, laminin-332 promoted the uptake of extracellular tyrosine and, subsequently, increased intracellular levels of tyrosine in both melanocytes and melanoma cells. Taken together, these data strongly suggest that keratinocyte-derived laminin-332 contributes to melanin production by regulating tyrosine uptake.
Collapse
Affiliation(s)
- Heesung Chung
- From the Department of Life Sciences, Research Center for Cellular Homeostasis and
| | - Hyejung Jung
- From the Department of Life Sciences, Research Center for Cellular Homeostasis and
| | - Jung-Hyun Lee
- From the Department of Life Sciences, Research Center for Cellular Homeostasis and
| | - Hye Yun Oh
- Department of Life Sciences, Interdisciplinary Program of EcoCreative, Ewha Womans University, Seoul 120-750, Korea and
| | - Ok Bin Kim
- Department of Life Sciences, Interdisciplinary Program of EcoCreative, Ewha Womans University, Seoul 120-750, Korea and
| | - Inn-Oc Han
- the College of Medicine, Department of Physiology and Biophysics, Inha University, Incheon 402-751, Korea
| | - Eok-Soo Oh
- From the Department of Life Sciences, Research Center for Cellular Homeostasis and
| |
Collapse
|
6
|
Tsakok T, Sheth N, Robson A, Gleeson C, Mallipeddi R. Lentigo maligna mimicking invasive melanoma in Mohs surgery: a case report. F1000Res 2014; 3:25. [PMID: 25075285 PMCID: PMC4097356 DOI: 10.12688/f1000research.3-25.v1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 01/15/2014] [Indexed: 12/26/2022] Open
Abstract
Lentigo maligna is a lentiginous proliferation of atypical melanocytes confined to the epidermis, typically on chronically sun-damaged skin. Following biopsy and exclusion of invasive disease, therapy may involve Mohs surgery, topical treatment or radiotherapy. However, lentigo maligna often involves adnexal structures, creating histological difficulty in distinguishing these foci from invasive melanoma. We present a case in which, during Mohs excision, a nodule of severely atypical melanocytes appeared to lie within the dermis, potentially altering treatment and prognosis. The use of laminin-5 provided a means of resolving this diagnostic dilemma, facilitating continuation of Mohs surgery until tumour clearance was achieved.
Collapse
Affiliation(s)
- Teresa Tsakok
- Dermatological Surgery and Laser Unit, St John's Institute of Dermatology, St Thomas' Hospital, London, UK
| | - Nisith Sheth
- Dermatological Surgery and Laser Unit, St John's Institute of Dermatology, St Thomas' Hospital, London, UK
| | - Alistair Robson
- Dermatological Surgery and Laser Unit, St John's Institute of Dermatology, St Thomas' Hospital, London, UK
| | - Catherine Gleeson
- Dermatological Surgery and Laser Unit, St John's Institute of Dermatology, St Thomas' Hospital, London, UK
| | - Raj Mallipeddi
- Dermatological Surgery and Laser Unit, St John's Institute of Dermatology, St Thomas' Hospital, London, UK
| |
Collapse
|
7
|
Gostyński A, Pasmooij AMG, Del Rio M, Diercks GF, Pas HH, Jonkman MF. Pigmentation and melanocyte supply to the epidermis depend on type XVII collagen. Exp Dermatol 2014; 23:130-2. [PMID: 24330315 DOI: 10.1111/exd.12304] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/08/2013] [Indexed: 12/16/2023]
Abstract
Genetic deficiency of type XVII collagen (C17), laminin-332 or type VII collagen causes epidermolysis bullosa (EB). Spontaneous correction of the deficiency, also known as revertant mosaicism, is caused by a second somatic mutation that restores protein expression resulting in clinically healthy (revertant) patches surrounded by fragile (mutant) skin. Interestingly, in some patients, patches of revertant skin show hyperpigmentation. To study the possible role of affected proteins in pigmentation and melanocyte distribution, we investigated clinical documentation and skin biopsy specimens of 13 revertant EB patients having correcting mutations in the COL17A1, LAMB3 or COL7A1 genes. Analysis revealed that lack of C17 led to decreased melanin intensity and melanocyte density in the epidermis when compared with the revertant patches. Reversions of LAMB3 and COL7A1 in keratinocytes did not influence clinical pigmentation or density of melanocytes. We conclude that in human skin, melanocyte supply to the epidermis depends on C17 expression in keratinocytes.
Collapse
Affiliation(s)
- Antoni Gostyński
- Center for Blistering Diseases, Department of Dermatology, University of Groningen, University Medical Center Groningen, Groningen, the Netherlands
| | | | | | | | | | | |
Collapse
|
8
|
Chung H, Suh EK, Han IO, Oh ES. Keratinocyte-derived laminin-332 promotes adhesion and migration in melanocytes and melanoma. J Biol Chem 2011; 286:13438-47. [PMID: 21349841 PMCID: PMC3075690 DOI: 10.1074/jbc.m110.166751] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2010] [Revised: 02/11/2011] [Indexed: 02/02/2023] Open
Abstract
Melanocytes are highly motile cells that play an integral role in basic skin physiological processes such as wound healing and proper skin pigmentation. It has been postulated that surrounding keratinocytes contribute to melanocyte migration, but underlying mechanisms remain rather vague so far. In this study, we set out to analyze the specific potential contribution of keratinocyte components to melanocytes and melanoma cell migration-related processes. Our studies revealed that A375 human melanoma cell attachment, spreading, and migration are interestingly better supported by HaCaT keratinocyte extracellular matrix (ECM) than by self-derived A375 ECM. Moreover, HaCaT ECM caused increased integrin α6 expression, adhesion-mediated focal adhesion kinase phosphorylation, and focal adhesion formations. Similar effects were confirmed in human melanocytes. Furthermore, we found that keratinocyte-derived soluble factors did not appear to significantly contribute to these processes. Specific extrinsic factors that promoted melanoma migration were attributed to keratinocyte-derived laminin-332, whereas alternative ECM component such as laminin-111 and fibronectin functions appeared to have insignificant contributions. Taken together, these studies implicate extrinsic laminin-332 in promoting the high mobility property and perhaps invasiveness inherently characteristic of, and that are the menace of, melanocytes and melanomas, respectively.
Collapse
Affiliation(s)
- Heesung Chung
- From the Division of Life and Pharmaceutical Sciences, Department of Life Sciences, and the Center for Cell Signaling & Drug Discovery Research, Ewha Womans University, Seoul 120-750, Korea and
| | - Eun-Kyung Suh
- From the Division of Life and Pharmaceutical Sciences, Department of Life Sciences, and the Center for Cell Signaling & Drug Discovery Research, Ewha Womans University, Seoul 120-750, Korea and
| | - Inn-Oc Han
- the Department of Physiology and Biophysics, College of Medicine, Inha University, Incheon 402-751, Korea
| | - Eok-Soo Oh
- From the Division of Life and Pharmaceutical Sciences, Department of Life Sciences, and the Center for Cell Signaling & Drug Discovery Research, Ewha Womans University, Seoul 120-750, Korea and
| |
Collapse
|
9
|
Oikawa Y, Hansson J, Sasaki T, Rousselle P, Domogatskaya A, Rodin S, Tryggvason K, Patarroyo M. Melanoma cells produce multiple laminin isoforms and strongly migrate on α5 laminin(s) via several integrin receptors. Exp Cell Res 2010; 317:1119-33. [PMID: 21195710 DOI: 10.1016/j.yexcr.2010.12.019] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2010] [Revised: 12/21/2010] [Accepted: 12/22/2010] [Indexed: 11/15/2022]
Abstract
Melanoma cells express and interact with laminins (LMs) and other basement membrane components during invasion and metastasis. In the present study we have investigated the production and migration-promoting activity of laminin isoforms in melanoma. Immunohistochemistry of melanoma specimens and immunoprecipitation/western blotting of melanoma cell lines indicated expression of laminin-111/121, laminin-211, laminin-411/421, and laminin-511/521. Laminin-332 was not detected. In functional assays, laminin-111, laminin-332, and laminin-511, but not laminin-211 and laminin-411, strongly promoted haptotactic cell migration either constitutively or following stimulation with insulin-like growth factors. Both placenta and recombinant laminin-511 preparations were highly active, and the isolated recombinant IVa domain of LMα5 also promoted cell migration. Function-blocking antibodies in cell migration assays revealed α6β1 integrin as the major receptor for laminin-111, and both α3β1 and α6β1 integrins for laminin-332 and laminin-511. In contrast, isolated LMα5 IVa domain-promoted melanoma cell migration was largely mediated via αVβ3 integrin and inhibited by RGD peptides. Given the ubiquitous expression of α5 laminins in melanoma cells and in melanoma-target tissues/anatomical structures, as well as the strong migration-promoting activity of these laminin isoforms, the α5 laminins emerge as putative primary extracellular matrix mediators of melanoma invasion and metastasis via α3β1 and other integrin receptors.
Collapse
Affiliation(s)
- Yuko Oikawa
- Department of Dental Medicine, Karolinska Institutet, Stockholm, Sweden
| | | | | | | | | | | | | | | |
Collapse
|
10
|
Swope VB, Supp AP, Schwemberger S, Babcock G, Boyce S. Increased expression of integrins and decreased apoptosis correlate with increased melanocyte retention in cultured skin substitutes. ACTA ACUST UNITED AC 2006; 19:424-33. [PMID: 16965271 DOI: 10.1111/j.1600-0749.2006.00325.x] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Losses of human melanocytes (HM) in transplantation of cultured skin substitutes (CSS) may result from poor cellular attachments. To test this hypothesis, HM integrin expression was measured in four culture media: (a) melanocyte growth medium (MGM), an HM proliferation medium; (b) UCMC 160, a CSS maturation medium; (c) mMGM, modified MGM with 1.8 mM calcium; and (d) modified UCMC 160 with HM supplements (mUCMC 160). HM grew well in all media except UCMC 160. Increased expression of beta1, beta4, alpha3beta1 and alpha5 integrins on HM cultured in MGM and mMGM versus UCMC 160 was found by flow cytometry. Annexin V-allophycocyanin (APC) labeled HM in apoptosis and increased significantly in UCMC 160 (31.1%) compared with MGM (11.9%) or mMGM (13.9%). CSS were incubated in UCMC 160, mMGM or mUCMC 160 media, and grafted to athymic mice. In the mMGM group, grafts were darker as measured with a chromameter through 6 weeks and the average number of basal HM per field was greater at 12 weeks post-grafting. Increased graft loss was observed in the mMGM group which corresponded with the poor epidermal morphology in vitro. Although HM retention improved in vivo using mMGM to culture the CSS, the stability of the epidermis decreased. These results indicate that expression of integrins on HM in vitro correlates with HM retention in CSS and short-term survival after transplantation, but that long-term survival depends also on stable epithelium.
Collapse
Affiliation(s)
- Viki B Swope
- Department of Surgery, University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | | | | | | | | |
Collapse
|
11
|
Krengel S, Stark I, Geuchen C, Knoppe B, Scheel G, Schlenke P, Gebert A, Wünsch L, Brinckmann J, Tronnier M. Selective down-regulation of the alpha6-integrin subunit in melanocytes by UVB light. Exp Dermatol 2005; 14:411-9. [PMID: 15885076 DOI: 10.1111/j.0906-6705.2005.00295.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
In vivo, melanocytes bind to laminin (LM) molecules of the basement membrane (BM) via the integrins alpha3beta1 and alpha6beta1, and they adhere to neighbouring keratinocytes via E-cadherin. Only few studies have addressed the impact of ultraviolet (UV) light on the interaction of melanocytes with their microenvironment. In this report, we examined the influence of UVB irradiation on the expression of the most important melanocyte-adhesion molecules (E-, N-cadherin, alpha2-, alpha3-, alpha5-, alpha6-, alphaV-, beta1-, beta3-integrins and ICAM-1) in vitro by flow cytometry. We were able to demonstrate that the alpha6-integrin subunit is selectively and reversibly down-regulated by UVB in a dwzm 150ose-dependent manner. In comparison, keratinocytes lacked UVB-inducible alterations in the expression of alpha6-integrin. In the presence of LM-1, the UVB-induced down-regulation of alpha6-integrin in melanocytes was significantly reduced. Moreover, LM-1 increased the resistance of melanocytes to UVB-induced cell death, as measured by annexinV-binding analysis. This effect was reversed by preincubation with an alpha6-integrin-blocking antibody. By immunofluorescence, we could demonstrate that UVB leads to a dose-dependent internalization of alpha6-integrin, providing an obvious explanation for the down-regulation on the outer cell surface observed by flow cytometry. We suggest that adhesion to LM-1 through alpha6-integrin represents a protective mechanism for melanocytes to withstand UVB damage. Through alpha6-integrin internalization, sunburns might alter the interaction between melanocytes and the BM, resulting in apoptosis induced by loss of anchorage (anoikis). Repeated sunburns may then lead to the selection of a population of melanocytes which are capable of anchorage-independent survival, culminating in solar nevogenesis and melanoma development.
Collapse
Affiliation(s)
- Sven Krengel
- Department of Dermatology, University of Lübeck, Lübeck, Germany.
| | | | | | | | | | | | | | | | | | | |
Collapse
|
12
|
Lei TC, Vieira WD, Hearing VJ. In vitro migration of melanoblasts requires matrix metalloproteinase-2: implications to vitiligo therapy by photochemotherapy. PIGMENT CELL RESEARCH 2002; 15:426-32. [PMID: 12453184 DOI: 10.1034/j.1600-0749.2002.02044.x] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
It is known that the migration of melanocyte precursors (melanoblasts) from the outer root sheath of hair follicles into clinically depigmented epidermis is crucial to the repigmentation of vitiliginous skin treated with photochemotherapy (PUVA), but such migratory cells must penetrate extracellular matrix tissue barriers in vivo. To test the hypothesis that matrix metalloproteinases (MMPs) are required for this process, we determined whether cultured melb-a cells, an immortal line of melanoblasts isolated from neonatal mouse epidermis, express and secrete MMPs and whether a synthetic metalloproteinase inhibitor, GM6001 (Galardin), inhibits their migratory behavior in vitro. Reverse transcriptase-polymerase chain reaction and Western blotting were used to determine the patterns of MMP expression by melanoblasts at the mRNA and protein levels, respectively. The proteolytic activities of MMPs secreted into the culture medium were assessed by gelatin zymography. The capacity of melanoblasts to migrate on fibronectin, laminin or laminin-5 substrates was estimated using Transwell migration assays. The results show that MMP2, MMP9 and MT1-MMP transcripts are expressed by these melanoblasts, but only MMP2 is secreted and activated in the extracellular environment. Although the therapeutic efficacy of PUVA in stimulating repigmentation of vitiliginous skin might derive from direct effects of UVA and/or 8-methoxypsoralen (8MOP), recent studies have shown that keratinocyte-derived factors induced by ultraviolet radiation, especially alpha-melanocyte stimulating hormone (alpha MSH), play a major role in regulating melanocyte function. Therefore, we also examined whether 8MOP and/or alphaMSH are involved in the up-regulation of MMP2 expression in melanoblasts. Western blotting and zymographic analyses revealed that MMP2 synthesis and secretion were induced by 8MOP and/or by alpha MSH. This induction of MMP2 resulted in significant increases of migration by melanoblasts on laminin or on laminin-5 substrates, while concomitant treatment with GM6001 blocked that induced migration. Taken together, these results suggest the importance of MMP2 in melanoblast migration and in the response to PUVA therapy.
Collapse
Affiliation(s)
- Tie Chi Lei
- Pigment Cell Biology Section, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | | | | |
Collapse
|