(151e) Metabolic Characteristic and Immunomodulation of Adipose-Derived Stem Cells during in Vitro Culture Expansion

Human mesenchymal stem cells (hMSCs) are known for their potential in regenerative medicine due to their ability to differentiate into multiple cell lines, secrete trophic factors, and regulate immune responses in damaged tissue. Preclinical studies have shown promising results for endogenous regeneration after hMSC transplantation in various diseases. To keep up with the cell demand for clinical trials, hMSCs, usually isolated from bone marrow, must be expanded in vitro to reach large quantity, which eventually leads to cellular senescence and loss of therapeutic functions. An increasing wealth of literature indicates that metabolic plasticity in bone marrow-derived hMSCs is associated with cellular senescence during in vitro culture. The redox cycle NAD+/NADH and Sirt-1 axis play an important role in regulating aging-related functional decline. To address the challenging isolation of hMSCs from bone marrow, other sources such as adipose tissue-derived stem cells (hASCs) have been considered as a promising alternative for cell therapy due to easy access and large tissue enrichment. However, differences have been observed for hASCs in context of metabolic characteristics and response to in vitro culture stress. The relationship between metabolic profiles and stem cell functions, especially the immunomodulatory ability of hASCs, is largely unknown compared to the thoroughly investigated bone marrow derived hMSCs. Therefore, in this study, we thoroughly evaluated changes in metabolism and redox cycles in hASCs during extensive culture expansion. From passage 5 (P5) to passage 12 (P12), hASCs did not respond to culture stress as significantly as bone marrow derived hMSCs. The results indicated the limited cellular senescence with well-preserved stem cell characteristics. In addition, we found that the NAD+/NADH redox cycle as well as metabolic homeostasis are well maintained in hASCs, indicating that hASC senescence may be regulated through an alternative mechanism rather than NAD+/-Sirt aging pathways. For immunomodulation, however, hASCs at high passage still exhibited a decline of potentials in response to an inflammatory environment. Moreover, we employed both proteomics and genomics analyses to identify the key metabolic pathways that may regulate immunomodulatory potentials in hASCs during culture expansion. Together, this study advances our understanding of metabolism and senescence in hMSCs from different tissue sources and provides guidance for in vitro biomanufacturing of hASCs for potential clinical applications.