1. Effect of Flightless I Expression on Epidermal Stem Cell Niche During Wound Repair
- Author
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Xanthe L. Strudwick, Claudine S. Bonder, Zlatko Kopecki, Gink N. Yang, Allison J. Cowin, Yang, Gink N, Strudwick, Xanthe L, Bonder, Claudine, Kopecki, Zlatko, and Cowin, Allison J
- Subjects
0301 basic medicine ,skin ,Niche ,Mice, Transgenic ,Biology ,Critical Care and Intensive Care Medicine ,030207 dermatology & venereal diseases ,03 medical and health sciences ,Mice ,wound repair ,0302 clinical medicine ,stem cells ,epidermis ,Proliferating Cell Nuclear Antigen ,Animals ,Stem Cell Niche ,Wnt Signaling Pathway ,beta Catenin ,Cell Proliferation ,Skin ,Mice, Inbred BALB C ,Wound Healing ,integumentary system ,Epidermis (botany) ,Stem Cells ,Microfilament Proteins ,Wnt signaling pathway ,Cell biology ,Disease Models, Animal ,030104 developmental biology ,Epidermal Cells ,Gene Knockdown Techniques ,Emergency Medicine ,Epidermal stem cell ,Trans-Activators ,Female ,Stem cell - Abstract
usc Objective: Activation of epidermal stem cells (EpSCs) from their quiescent niche is an integral component of wound reepithelialization and involves Wnt/β-catenin (β-Cat) signaling and remodeling of the actin cytoskeleton. The aim of this study was to investigate the effect of Flightless I (Flii), a cytoskeletal protein and inhibitor of wound healing, on EpSC activation during wound repair. Approach: Genetically modified Flii mice (Flii knockdown: Flii+/−, wild type: WT, Flii overexpressing: FliiTg/Tg) received two incisional wounds along the lateral axis of the dorsal skin. Indicators of EpSC activation (epidermal growth factor receptor 1 [EGFR1], leucine-rich repeats and immunoglobulin-like domains-1 [Lrig1], K14), Wnt/β-Cat signaling (Lgr6, Flap2, β-Cat, and axis inhibition protein 2 [Axin2]), and cell proliferation (proliferating cell nuclear antigen [PCNA]) were assessed using immunohistochemistry. β-Cat stabilization was examined using western blotting with cell cycling and differentiation of isolated CD34+ITGA6high EpSCs examined using real time-quantitative polymerase chain reaction after treatment with wound-conditioned media. Results:Flii+/− led to increased numbers of activated EpSCs expressing PCNA, elevated EGFR1, and decreased Lrig1. EpSCs in Flii+/− hair follicle niches adjacent to the wounds also showed expression of Wnt-activation markers including increased β-Cat and Lgr6, and decreased Axin2. EpSCs (CD34+ITGA6high) isolated from Flii+/− unwounded skin showed elevated expression of cell-cycling genes including ΔNp63, filaggrin (Fila), involucrin (Invo), cyclin D1 (Ccnd1), and cell-division cycle protein-20 (Cdc20); and elevated ΔNp63 and Invo after treatment with wound-conditioned media compared with WT and FliiTg/Tg counterparts. Innovation: Flii was identified as an inhibitor of EpSC activation that may explain its negative effects on wound reepithelialization. Conclusion: Flii may inhibit EpSC activation by interrupting Wnt/β-Cat signaling. Strategies that reduce Flii may increase activation of EpSCs and promote reepithelialization of wounds. Refereed/Peer-reviewed
- Published
- 2018