L. Liao, Y. Shuai, Y. Jin, Weidong Tian
Mesenchymal stem cells (MSCs) are promising candidates for oral tissue regeneration and disease treatment. However, long-term in vitro passaging leads to stemness loss of MSCs, resulting in failure of MSCs therapy [1-2]. Here, we report a small molecule (SM)-based strategy to improve cell therapy of long-term cultured MSCs.
Firstly, we established a high-throughput screen system to isolate SM that could prevent senescence during long-term passaging. After high throughput screening, four SMs that efficiently prevented replicative senescence of MSCs were isolated. The formula of SM was efficient to preserve self-renewal and differentiation properties of rat bone marrow MSCs after long-term passaging. SM treatment did not affect the colony forming, proliferation and osteogenic differentiation of MSCs cultured for 1 or 4 passages, but largely prevented the decline of self-renew and differentiation capacity of MSCs cultured for 15 passages in vitro. Furthermore, heterotopic osteogenesis assay, critical size calvarial defects repair assay, and osteoporosis treatment assay strongly certified that melatonin preserved the therapeutic effect of long-term passaged MSCs on bone regeneration in vivo. Mechanistically, the SM formula functioned by activating antioxidant defense system, inhibiting the pathway of cell senescence, and preserving the expression of gene governing the stemness. In conclusion, the small molecule formula efficiently prevents the dysfunction and therapeutic failure of MSCs after long-term passaging, providing a practical strategy to improve the application of MSCs in tissue engineering and bone regeneration.