Organotypic Cocultures as Models to Study Cell-Cell and Cell-Matrix Interactions of Human Hair Follicle Cells

Abstract

In the hair follicle complex interactions of specialized epithelial and mesenchymal cells as well as extracellular components are crucial for regulation of proliferation and differentiation. In order to mimic this situation in vitro, techniques to cultivate follicular cells such as outer root sheath (ORS) cells, hair matrix cells (HMC) and hair papilla cells (HPC) were developed. Human dermal fibroblasts (HDF) and HPC markedly enhanced proliferation of ORS cells when cocultured spatially separated in a two-chamber system, which was more pronounced with postmitotic than with mitotic mesenchymal cells. In organotypic cocultures of ORS cells on HDF- or HPC-populated collagen gels lifted at the air-medium interface, stratified epithelia developed largely reminiscent of the epidermis. The morphology was well structured and differentiation markers were expressed (e.g. suprabasal keratins, filag-grin, involucrin, basement membrane components). Both proliferation and differentiation were dependent on the presence of HDF or HPC. When grown embedded in extracellular matrix (Matrigel) without HDF, ORS cells formed large spheroids with inward directed differentiation. Also herein HDF or HPC sustained both cell growth and balanced, epidermis-type differentiation. While in organotypic cocultures with HDF, HMC also organized into stratified epithelia, epidermis-type stratification was prevented by HPC. Similarly, in the presence of HDF, HMC in Matrigel formed keratinizing spheroids, whereas this was largely suppressed in the presence of HPC. However, hair-type differentiation was not observed, suggesting a crucial role of other yet unknown components or of the surrounding matrix.

Use of Epidermal Equivalents Generated from Follicular Outer Root Sheath Cells in vitro and for Autologous Grafting of Chronic Wounds

“…Numerous in vitro applications of organotypic (co)cultures including our model of epidermal equivalents have been described in the literature (table 1) [Limat et al, 1994[Limat et al, , 1999Wiszniewski et al, 2000].…”

Vellus Hair Follicle-Derived Keratinocyte Culture: A New Experimental Model in Human Hair Research

“…Therefore various in vitro culture models have been established mainly focusing on three targets (table 1): culturing single cell populations o f epithelial or mesenchymal origin using sub merged culture techniques with or without biological substrata or lifting the cells at the air liquid interface [3][4][5][6][7][8][9][10][11][12][13], (2) using organo typic or coculture techniques [14][15][16][17] based on the recombination of single cell populations, and (3) development o f organ culture models [18,19] for culturing complete human hair follicles in vitro and maintaining them in the anagen phase. All these established model sys tems can be useful to study the human termi nal hair follicle and to understand controlling mechanisms of the hair cycle and its regula tion.…”

Hair follicular cell/organ culture in tissue engineering and regenerative medicine

“…Alternatively, a mixture of Matrigel, DPCs, and ORSCs are placed on top of a pseudodermis (mixed sandwich). A comparison of these systems indicated that the mixed sandwich system cultivated under continuously submerged conditions in serum-free, low-calcium medium meets all basic criteria and offers several advantages over previously available assays [75][76][77]. Havlikova et al report a pragmatic human folliculoid microsphere (HFM) assay that meets all of the basic and modified prerequisites for in vitro higher throughput screening systems for the preclinical screening of candidate hair drugs [78].…”