High-throughput reconstitution of epithelial-mesenchymal interaction in folliculoid microtissues from dissociated adult cells

  • Chih-Chieh Chan, Dermatology, National Taiwan University Hospital & Institute of Biomedical Engineering, National Taiwan University, Taiwan
  • Chien-Mei Yen, Institute of Biomedical Engineering, National Taiwan University, Taiwan
  • Jin-Bon Hong, Department of Dermatology, Yunlin Branch and Taipei Main Campus, National Taiwan University Hospital, Taiwan
  • Sung-Jan Lin, Dermatology, National Taiwan University Hospital & Institute of Biomedical Engineering, National Taiwan University, Taiwan

The aim of this study is to develop a method for efficient production of folliculoid keratinocyte-dermal papilla (DP) microtissues to facilitate epithelial-mesenchymal interaction. The behavior of DP cells and adult keratinocytes from hairless skin on poly(ethylene-co-vinyl alcohol) (EVAL) surface is investigated. Keratinocytes, poorly adherent both to substrate and between homotypic cells, become suspended disperse cells after homotypic cell seeding. Seeded simultaneously, keratinocytes and DP cells are able to aggregate into more than 2000 spheroidal microtissues after one single seeding. Dynamical analysis shows that DP cells act as a carrier in the process due to the heterotypic intercellular adhesion. DP cells attach faster to EVAL and start to aggregate. Keratinocytes adhere to DP cells and are then carried by DP cells to form initial hybrid aggregates. Due to the high motility of DP cells, these hybrid aggregates move collectively as clusters and merge into larger spheroids which subsequently detach from the substratum and can be easily collected. Compared with random cell distribution in spheroids generated in hanging drops, these hybrid spheroids have a preferential compartmented core-shell structure: an aggregated DP cell core surrounded by a keratincoyte shell. In addition to ameliorated DP signature gene expression, keratinocytes show down-regulated epidermal terminal differentiation (K10,loricrin ) and enhanced follicular differentiation (K6). Functionally, these microtissues are able to grow hairs in vivo. This work sheds light on the complex effects and dynamics of cell-cell and cell-substratum interaction in the patterning of heterotypic cells into tissue forms and is of potential to be applied to mass generation of other epithelial organ primordia in vitro.