Autophagy Activation in Mesenchymal Stem Cells with Lithium Chloride and Trehalose: Implications for Regenerative Medicine

Background/Objectives: Mesenchymal stem cells (MSCs) are deemed to be a highly safe model for autologous and allogeneic cellular therapy, owing to their inherent lack of HLA-DR expression, immunomodulatory properties, homing ability, and plasticity allowing differentiation into different cell types. The interest in activating autophagic signaling in MSCs has recently grown due to its significant potential in maintaining stemness, enhancing paracrine signaling, and providing therapeutic benefits for cancer and neurodegenerative diseases. This study aimed to explore the impact of autophagy induction on enhancing the therapeutic potential of MSCs by maintaining their plasticity and to assess different induction agents. Methods: In this study, MSCs were first extracted from the fat tissue of Sprague–Dawley (SD) rats and characterized phenotypically and molecularly by their positive expression of stemness markers CD29, CD106, and CD44, and their negative expression of hematopoietic surface markers CD14, CD34, and CD45, using a flow cytometry approach. Isolated MSCs were then treated separately with two FDA-approved autophagy inducers: Lithium Chloride and Trehalose, following assessment of autophagy activity. Results: Treated MSCs showed significant increases in autophagic activity at both the transcriptional and translational levels. The successful induction of autophagy in MSCs was confirmed through the elevated expression of autophagy-related genes such as ATG3, ATG13, ATG14, P62, and ULK1. These data were confirmed by the significant upregulation in LC3 protein expression and the formation of autophagosomes, which was detected using a transmission electron microscope. Furthermore, the expression of Oct4, Sox2, and Nanog genes was significantly enhanced after treatment with Trehalose and Lithium Chloride compared with untreated control MSCs which may indicate an upregulation of pluripotency. Meanwhile, Lithium Chloride and Trehalose did not significantly induce cellular apoptosis, indicated by the Bax/Bcl-2 expression ratio, and significantly decreased the expression of the antioxidant markers SOD and GPx. Conclusions: Treatment of MSCs with Trehalose and, in particular, Lithium Chloride significantly activated autophagic signaling, which showed a profound effect in enhancing cells’ pluripotency, reinforcing the usage of treated MSCs for autologous and/or allogenic cellular therapy. However, further in vivo studies for activating autophagy in cellular grafts should be conducted before their use in clinical trials.