title: Three-dimensional epithelial and mesenchymal cell co-cultures form early tooth epithelium invagination-like structures: expression patterns of relevant molecules.
abstract: Epithelium invagination is the key feature of early tooth development. In this study, we built a three-dimensional (3D) model to represent epithelium invagination-like structure by tissue engineering. Human normal oral epithelial cells (OECs) and dental pulp stem cells (DPSCs) were co-cultivated for 2-7 weeks on matrigel or collagen gel to form epithelial and mesenchymal tissues. The histological change and gene expression were analyzed by HE staining, immunostaining, and quantitative real-time RT-PCR (qRT-PCR). After 4 weeks of cultivation, OECs-formed epithelium invaginated into DPSCs-derived mesenchyme on both matrigel and collagen gel. OEC-DPSC co-cultures on matrigel showed typical invagination of epithelial cells and condensation of the underlying mesenchymal cells. Epithelial invagination-related molecules, CD44 and E-cadherin, and mesenchymal condensation involved molecules, N-cadherin and Msx1 expressed at a high level in the tissue model, suggesting the epithelial invagination is functional. However, when OECs and DPSCs were co-cultivated on collagen gel; the invaginated epithelium was transformed to several epithelial colonies inside the mesenchyme after long culture period. When DPSCs were co-cultivated with immortalized human OECs NDUSD-1, all of the above-mentioned features were not presented. Immunohistological staining and qRT-PCR analysis showed that p75, BMP2, Shh, Wnt10b, E-cadherin, N-cadherin, Msx1, and Pax9 are involved in initiating epithelium invagination and epithelial-mesenchymal interaction in the 3D OEC-DPSC co-cultures. Our results suggest that co-cultivated OECs and DPSCs on matrigel under certain conditions can build an epithelium invagination-like model. This model might be explored as a potential research tool for epithelial-mesenchymal interaction and tooth regeneration.
authors.affiliation: Department of Pharmacology, The Nippon Dental University School of Life Dentistry at Tokyo, 1-9-20 Fujimi, Chiyoda-ku, Tokyo 102-8159, Japan. xiaoli@tky.ndu.ac.jp
authors.forename: Li
authors.initials: L
authors.lastname: Xiao
authors.forename: Takeki
authors.initials: T
authors.lastname: Tsutsui
mesh_terms: D000293:Adolescent; D000328:Adult; D055396:Bone Morphogenetic Protein 2 / Q000378:metabolism; D015820:Cadherins / Q000096:biosynthesis; D002478:Cells, Cultured; D018920:Coculture Techniques; D003094:Collagen; D003782:Dental Pulp / Q000196:embryology* / Q000378:metabolism; D004338:Drug Combinations; D004847:Epithelial Cells / Q000502:physiology; D058750:Epithelial-Mesenchymal Transition; D004848:Epithelium / Q000378:metabolism; D005260:Female; D053823:Hedgehog Proteins / Q000378:metabolism; D006801:Humans; D018960:Hyaluronan Receptors / Q000378:metabolism; D007797:Laminin; D051957:MSX1 Transcription Factor / Q000096:biosynthesis; D008297:Male; D059630:Mesenchymal Stem Cells / Q000166:cytology / Q000502:physiology*; D008648:Mesoderm; D009805:Odontogenesis / Q000235:genetics; D051764:PAX9 Transcription Factor / Q000378:metabolism; D011509:Proteoglycans; D011518:Proto-Oncogene Proteins / Q000378:metabolism; D020800:Receptor, Nerve Growth Factor / Q000378:metabolism; D012038:Regeneration / Q000502:physiology*; D013234:Stem Cells / Q000166:cytology / Q000502:physiology*; D023822:Tissue Engineering; D014070:Tooth / Q000196:embryology* / Q000254:growth & development / Q000378:metabolism; D051153:Wnt Proteins / Q000378:metabolism; D055815:Young Adult
chemical_list: C525718:BMP2 protein, human; D055396:Bone Morphogenetic Protein 2; D015820:Cadherins; D004338:Drug Combinations; D053823:Hedgehog Proteins; D018960:Hyaluronan Receptors; D007797:Laminin; D051957:MSX1 Transcription Factor; C484083:MSX1 protein, human; D051764:PAX9 Transcription Factor; C497323:PAX9 protein, human; D011509:Proteoglycans; D011518:Proto-Oncogene Proteins; D020800:Receptor, Nerve Growth Factor; C509239:SHH protein, human; C491119:WNT10B protein, human; D051153:Wnt Proteins; C059485:matrigel; D003094:Collagen