Tendon Biomimetic Electrospun PLGA Fleeces Induce an Early Epithelial-Mesenchymal Transition and Tenogenic Differentiation on Amniotic Epithelial Stem Cells

Background. The design of tendon biomimetic electrospun fleece with Amniotic Epithelial Stem Cells (AECs) that have shown a high tenogenic attitude may represent an alternative strategy to overcome the unsatisfactory results of conventional treatments in tendon regeneration. Methods. In this study, we evaluated AEC‐engineered electrospun poly(lactide‐co‐glycolide) (PLGA) fleeces with highly aligned fibers (ha‐PLGA) that mimic tendon extracellular matrix, their biocompatibility, and differentiation towards the tenogenic lineage. PLGA fleeces with randomly distributed fibers (rd‐PLGA) were generated as control. Results. Optimal cell infiltration and biocompatibility with both PLGA fleeces were shown. However, only ha‐PLGA fleeces committed AECs towards an Epithelial‐Mesenchymal Transition (EMT) after 48 h culture, inducing their cellular elongation along the fibers’ axis and the upregulation of mesenchymal markers. AECs further differentiated towards tenogenic lineage as confirmed by the up‐regulation of tendon‐related genes and Collagen Type 1 (COL1) protein expression that, after 28 days culture, appeared extracellularly distributed along the direction of ha‐PLGA fibers. Moreover, long‐term co‐cultures of AEC‐ha‐PLGA biohybrids with fetal tendon explants significantly accelerated of half time AEC tenogenic differentiation compared to ha‐PLGA fleeces cultured only with AECs. Conclusions. The fabricated tendon biomimetic ha‐PLGA fleeces induce AEC tenogenesis through an early EMT, providing a potential tendon substitute for tendon engineering research. This research was supported by the Italian Ministry for Instruction, University and Research (MIUR) under the National Operative Program (PON): Programma Operativo Nazionale Ricerca e Innovazione 2014‐ 2020 (CCI 2014IT16M2OP005), Fondo Sociale Europeo (FSE), Azione I.1 “Dottorati Innovativi con caratterizzazione Industriale (grant number C42F16000350001)