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DOI: 10.1055/s-0030-1268917
Mesenchymal transition of amnion epithelial cells for cardiac cell therapy
Objective: Amnion epithelial cells (AEC) are a readily available cell source for potential use in regenerative medicine. Subpopulations of AEC express early stem cell markers and display stem cell behaviour, but usually AEC behave like mature epithelial cells. We sought to induce epithelial-to-mesenchymal transition (EMT) in AEC to improve their capacity for cardiovascular regeneration.
Methods: Human AEC were derived from full-term placenta and expanded in customized media. To induce EMT, transforming growth factor-β (TGF- β) was added in different concentrations. EMT was then assessed by analysis of cell morphology, immunocytology staining, in vitro scratch wound assay, and Transwell cell migration assay.
Results: Following primary expansion in conditioned media, AEC expressed SSEA-3, SSEA-4, TRA1–60, TRA1–81, Oct-3/4, Nanog, SOX-2, and showed trilineage differentiation capacity. At higher passages under standard culture condition, however, AEC lost Oct-4 expression and behaved like mature epithelial cells. Nevertheless, 25ng/ml TGF- β added to the medium for 5–6 days induced striking changes in AEC morphology. Cells acquired a fibroblastoid shape resembling to that of mesenchymal stem cells. By immunocytology, TGF-β induced up-regulation of N-cadherin and down-regulation of E-cadherin. In the scratch wound assay, TGF-β stimulated AEC displayed an irregular migration pattern that lead to accelerated wound closure, and only stimulated AEC migrated to the lower Transwell chamber through an 8µm membrane.
Conclusion: Under the influence of TGF-β, mature AEC undergo epithelial-to-mesenchymal transition and acquire a mesenchymal stem cell-like phenotype. EMT greatly enhances cell mobility and may thus help optimize AEC for use in cardiovascular cell therapy.