Comparative Analysis of Ectodermal Marker Expression in Human Adipose-Derived Stem Cells and Amniotic Epithelial Cells Exposed to Ectoderm-Inducing Conditions

Nervous system and corneal disorders are major causes of permanent disability worldwide, largely due to the limited regenerative capacity of ectoderm-derived tissues. Therefore, the development of accessible and ethically acceptable cell-based therapies promoting the repair and regeneration of these tissues is of considerable translational importance. In this study, we aimed to comparatively evaluate the ectodermal differentiation potential of human adipose-derived stem cells (ADSCs) and human amniotic epithelial cells (hAECs) in vitro, with hAECs serving as a reference cell population with established ectodermal plasticity. Primary ADSCs and hAECs were characterized phenotypically using flow cytometry and functional differentiation assays. Cells were subjected to a directed ectodermal differentiation protocol and assessed via morphological analysis, immunostaining for ectoderm-associated proteins, and RT-qPCR analysis of lineage-specific genes. ADSCs exhibited morphological changes following differentiation, including a more epithelial-like phenotype and an increased nucleus-to-cytoplasm ratio. Immunostaining revealed the induction of nestin and OTX2 expression after differentiation, which was particularly pronounced in ADSCs. Gene expression analysis demonstrated statistically significant upregulation of the ectoderm-related genes EN2, SOX1, and PAX6 exclusively in hAECs. Results suggest that in ADSCs the differentiation process was only partially activated. In conclusion, our findings further support the suitability of hAECs as a reference cell line for studies investigating ectodermal differentiation protocols, while also demonstrating that ADSCs exhibit a limited but detectable capacity for acquiring ectoderm-specific characteristics under defined in vitro culture conditions.