Changes in stemness properties of human adenoid-derived mesenchymal stem cells during in vitro aging

Mesenchymal stem cells (MSCs) have significant therapeutic potential in gene therapy. In vitro replicative senescence causes a decrease in the proliferation capacity of MSCs and changes in stem cell properties. In this study, adenoid tissue was focused as a new MSC source. The stem cell properties and the proliferation potential of adenoid-derived MSCs after the long-term in vitro replicative senescence were investigated. Adenoid-derived MSCs (A-MSCs) were cultured up to passage 20 and were analysed for cell morphology, proliferative capacity, differentiation potential, and surface marker expression. In addition, the expression profile of cell cycle, apoptosis, and senescence-related genes were evaluated. After in vitro replicative senescence, A-MSCs did not show any significant morphological differences. The proliferation potential of A-MSCs was rapid up to passage 16, and a reduction in the proliferation potential of senescent cells in vitro was observed depending on the passage number. The differentiation potential of late-passage A-MSCs was also reduced compared to early-passage cells. A-MSCs also provided significant closure at the 8th hour in early passages in terms of closure of the scratch area, while late passage A-MSCs exhibited a similar closure profile at the 24th hour. At the transcriptional level, the upregulation of the BAX gene and the downregulation of the p21 and p53 genes suggest that late-passage A-MSCs may not exhibit a senescence profile. In conclusion, A-MSCs have significant potential for clinical use due to the sustainability of MSC properties and their ability to proliferate and migrate with long-term culture.