title: Direct conversion of mouse embryonic fibroblasts into functional keratinocytes through transient expression of pluripotency-related genes.
abstract: The insufficient ability of specialized cells such as neurons, cardiac myocytes, and epidermal cells to regenerate after tissue damage poses a great challenge to treat devastating injuries and ailments. Recent studies demonstrated that a diverse array of cell types can be directly derived from embryonic stem cells (ESCs), induced pluripotent stem cells (iPSCs), or somatic cells by combinations of specific factors. The use of iPSCs and direct somatic cell fate conversion, or transdifferentiation, holds great promise for regenerative medicine as these techniques may circumvent obstacles related to immunological rejection and ethical considerations. However, producing iPSC-derived keratinocytes requires a lengthy two-step process of initially generating iPSCs and subsequently differentiating into skin cells, thereby elevating the risk of cellular damage accumulation and tumor formation. In this study, we describe the reprogramming of mouse embryonic fibroblasts into functional keratinocytes via the transient expression of pluripotency factors coupled with directed differentiation. The isolation of an iPSC intermediate is dispensable when using this method. Cells derived with this approach, termed induced keratinocytes (iKCs), morphologically resemble primary keratinocytes. Furthermore they express keratinocyte-specific markers, downregulate mesenchymal markers as well as the pluripotency factors Oct4, Sox2, and Klf4, and they show important functional characteristics of primary keratinocytes. iKCs can be further differentiated by high calcium administration in vitro and are capable of regenerating a fully stratified epidermis in vivo. Efficient conversion of somatic cells into keratinocytes could have important implications for studying genetic skin diseases and designing regenerative therapies to ameliorate devastating skin conditions.
authors.affiliation: Department of Biological Sciences, University of Cyprus, Nicosia, Cyprus.
authors.forename: Demetris
authors.initials: D
authors.lastname: Iacovides
authors.affiliation: Department of Biological Sciences, University of Cyprus, Nicosia, Cyprus.|Current address: Department of Biology, Massachusetts Institute of Technology, Cambridge, MA, USA.
authors.forename: Gizem
authors.initials: G
authors.lastname: Rizki
authors.affiliation: Transgenic Mouse Facility, Cyprus Institute of Neurology and Genetics, Nicosia, Cyprus.
authors.forename: Georgios
authors.initials: G
authors.lastname: Lapathitis
authors.affiliation: Department of Biological Sciences, University of Cyprus, Nicosia, Cyprus. strati@ucy.ac.cy.
authors.forename: Katerina
authors.identifier: http://orcid.org/0000-0002-2332-787X
authors.initials: K
authors.lastname: Strati
mesh_terms: D000818:Animals; D055415:Bone Morphogenetic Protein 4 / Q000494:pharmacology; D002454:Cell Differentiation; D065150:Cellular Reprogramming; D004622:Embryo, Mammalian; D000078404:Epidermal Cells; D004817:Epidermis / Q000378:metabolism; D005347:Fibroblasts / Q000166:cytology* / Q000187:drug effects / Q000378:metabolism; D005786:Gene Expression Regulation; D015603:Keratinocytes / Q000166:cytology* / Q000187:drug effects / Q000378:metabolism / Q000637:transplantation*; D000090062:Kruppel-Like Factor 4; D051741:Kruppel-Like Transcription Factors / Q000235:genetics / Q000378:metabolism; D051379:Mice; D008819:Mice, Nude; D008822:Mice, Transgenic; D050814:Octamer Transcription Factor-3 / Q000235:genetics / Q000378:metabolism; D012038:Regeneration / Q000235:genetics*; D055748:SOXB1 Transcription Factors / Q000235:genetics / Q000378:metabolism; D019076:Transgenes; D014212:Tretinoin / Q000494:pharmacology
chemical_list: D055415:Bone Morphogenetic Protein 4; C000715468:Klf4 protein, mouse; D000090062:Kruppel-Like Factor 4; D051741:Kruppel-Like Transcription Factors; D050814:Octamer Transcription Factor-3; C494174:Pou5f1 protein, mouse; D055748:SOXB1 Transcription Factors; C527783:Sox2 protein, mouse; D014212:Tretinoin
keywords: Direct reprogramming; Keratinocytes; Transdifferentiation