A diagnostic biomarker that predicts human bone marrow-derived mesenchymal stem cell scalability

Background & Aim Extreme donor-to-donor variability in scalability and the maintenance of stemness remain a major bottleneck to the therapeutic application of human mesenchymal stem cells (hMSCs). Current best practice monitors stemness by an array of cell-based assays that are lengthy and poorly differentiate between donor hMSCs of varying quality. To date, no markers can reliably determine the therapeutic quality of hMSCs during ex vivo expansion. To address this limitation, the study aimed to identify markers of MSC potency. Methods, Results & Conclusion Global transcriptomic analysis on high- and low-growth capacity donor hMSCs, stratified according to their in vitro proliferative potential revealed that high-growth capacity hMSCs lacked the expression of the gene encoding glutathione S-transferase theta 1 (GSTT1) as a result of gene deletion. Further characterization of these hMSCs demonstrated increased proliferative rate, clonogenicity, and longer telomere length compared to low-growth capacity GSTT1-positive hMSCs. In addition, detailed molecular profiling on GSTT1-homozygous negative and positive hMSCs showed that genes related to proliferation, inflammation and Wnt signaling were differentially regulated between them. This study identifies GSTT1 as a novel genomic DNA biomarker for MSC scalability. We advocate the further development of this biomarker as a tool to screen donors prior to painful and expensive surgical harvesting of their bone marrow.