Histochemical analysis of self-organizing 3D spheroid-like cultures of adipose-derived mesenchymal stem cells

Abstract

Histochemical staining demonstrated fusion of cells with formation of syncytium-like structures. On the periphery cells were polygonal, round, had epithelial morphology. Groups of cells organized in line inside spheroid remained elongated AD-MSC shape. Most of the cells did not proliferate. There were no migrating SMA+ cells. Polygonal cells on the periphery and a few cells inside the spheroid were desmin+. Interestingly, peripheral and elongated shape cells expressed epithelial marker CK-19+. Probably, within spheroid there was spontaneous mesenchymal-epithelial transdifferentiation. When spheroids were placed in a new culture dish we observed explantational outgrowth of spindle-shaped AD-MSC suggesting that cells within spheroids were alive, able to outgrow and revert through epithelial-mesenchymal transdifferentiation back to MSC phenotype. Investigation was funded by RFBR grant 18-04-01133 and supported by Program of Competitive Growth of KFU.