Transcriptomic Insights into the effect of Mesenchymal Stromal Cells Culture Medium on the Hematopoietic Stem/Progenitor Cells Co-culture

To investigate the molecular mechanisms underlying the altered hematopoietic support of mesenchymal stromal cells (MSC) expanded in human platelet lysate (hPL)-supplemented medium, we performed a comprehensive transcriptomic analysis comparing hPL-MSC and fetal bovine serum (FBS)-expanded MSC. MSC from three bone marrow donors were cultured under different adaptation regimens and co-cultured with hematopoietic stem and progenitor cells (HSPC). Transcriptomic analysis revealed distinct gene expression profiles, with 13% of genes differentially expressed between hPL-MSC and FBS-MSC, impacting cell signaling, extracellular matrix, and chemotaxis. Key pathways, including TGF-beta, PI3K-Akt, and Wnt signaling, were altered, affecting MSC-mediated HSPC expansion. hPL-MSC exhibited increased expression of inhibitory factors and reduced expression of promoters of HSPC proliferation, influencing Notch, TGF-β, JAK/STAT, and Wnt regulation. These findings highlight critical molecular interactions in MSC-HSPC co-culture and provide insights for optimizing xeno-free MSC expansion for hematopoietic applications.