De novo hair formation by cultured adult cells
Date Issued
2015
Date
2015
Author(s)
Chan, Chih-Chieh
Abstract
Like other organs including cornea and salivary gland, the development and cyclic growth of hair follicle (HF) is also governed by epithelial-mesenchymal interaction. Dermal papilla (DP) cells, the HF mesenchymal cells, have been shown to regulate hair growth and cycles, at least in part through its interaction with follicular epithelial cells or stem cells. Whenever the interaction is interrupted or disturbed, affected individual will develop various hair diseases. The most common hair loss, androgenetic alopecia (AGA), results from follicular miniaturization and shortened growth period in hair cycles. The hair organ miniaturization in AGA is considered to be a normal aging process. However, for those who are young with early development of AGA, the process seems to be “premature” that might have something to do with the follicular environment and hormonal change. What leads to the premature aging is not yet elucidated. Current therapeutic options for hair loss are either surgical redistribution of scalp hairs, or medical treatments including oral or topical preparations. These clinically available surgical or non-surgical treatments do not increase patient’s follicular units. To ultimately solve the problem of hair loss, the best way is to generate new hair follicles. Resembling embryonic hair morphogenesis, adult hair neogenesis involves delicate signal reciprocations between follicular epidermal cells and mesenchymal DP cells. New and considerable HFs can be generated by the advances in the techniques to combine inductive cultured DP cells and competent epidermal stem cells. Most regeneration models prefer to use cultured adult DP cells and “newborn” epidermis, taking the advantage of the multipotency of the newborn epidermal cells. This strategy is not applicable in the clinical aspect since the end goal of hair regeneration is to take cells from alopecia individuals who are mostly adult. Current hair regeneration models remain unable to efficiently expand folliculogenic adult epidermal cells. Only with large number of competent adult epidermal cells can we eventually apply the hair regeneration technique to adult individuals. To study the effect of in vitro epidermal-mesenchymal interaction and its impact on hair follicle regeneration, we cultured keratinocytes and DP cells into the same dish before they are used in further hair regeneration experiments. High passage rat epidermal cells successfully responded and formed hair shafts in the initial experiments. The in vitro epidermal-mesenchymal interaction distinctly changes epidermal cells to express elevated hair-specific genes. Our data showed the cultivated adult cells recapitulate the epidermal-mesenchymal interaction that induces the high passage epidermal cells to adopt the follicular fate and head to hair follicle differentiation. This acquired hair induction ability provides a new field for bioengineered hairs that not only the dermal cells but also the epidermal cells can be taken for population expansion before hair regeneration. This finding simply announces the possibility of removing one single adult hair, separately expanding dermal and epidermal cell numbers, and then coculturing these considerable amounts of cells before finally mixing them to form numerous new hairs. Successful development of this model and clarification of the underlying mechanism may lead to future large-scale hair production by bioengineering these adult follicular cells.
Subjects
coculture
folliculogenic
trichogenic
hair regeneration
alopecia
keratinocyte
Type
thesis
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