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Melanocytes, melanin-synthesis, and related signaling pathway

Abstract : The first part of the thesis was to define and validate an epidermal cell extraction method being the simplest, the most effective and applicable to smaller samples and avoiding animal reagents. In this study, TrypLE™, an animal origin-free cell dissociation enzyme, replaced dispase and trypsin as dissociated enzyme for melanocytes extraction. This product could simplify extraction protocol, eliminate potential pathogenic contaminants from animal and decrease keratinocytes contamination during extraction and subculture of melanocytes. The extraction efficiency was judged on the following criteria: separation epidermis / dermis, functionality of the extracted melanocytes (proliferation, melanin synthesis).The second part of the thesis was to explore the role of cross-talking between epidermis and dermis in hyperpigmentation, focused on Dickkopf-related protein l(Dkkl) which is secreted by dermal fibroblast and encoded by Dkkl gene is an antagonistic inhibitor of the Wnt signaling pathway, by isolating the LRP5/6 co-receptor and preventing the Frizzeled-Wnt-LRP5/6 complex formation. We hypothesized that TGF-βl mediates development of solar lentigo by reducing Dkkl expression in fibroblasts through the p38 MAP kinase pathway, which leads to an activation of the Wnt/ β-catenin signaling cascade. This hypothesis was confirmed in the fibroblast of lentigo and adjacent normal skin, also in the UV A-irradiation 3D skin mode! by testing of Dkkl secretion in protein level and Dkkl expression in RNA level.
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Submitted on : Monday, June 25, 2018 - 4:29:07 PM
Last modification on : Wednesday, September 16, 2020 - 10:43:31 AM
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  • HAL Id : tel-01823030, version 1



Yinjuan Wang. Melanocytes, melanin-synthesis, and related signaling pathway. Dermatology. Université Bourgogne Franche-Comté, 2017. English. ⟨NNT : 2017UBFCE005⟩. ⟨tel-01823030⟩



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