Mesenchymal stem cell secretome

Adult neural stem cells (aNSCs) show multilineage differentiation potential influenced by intrinsic and extrinsic signaling cues. We and others have shown that stimulation of aNSCs with bone marrow mesenchymal stem cell (MSC) secreted factors substantially enhances in vitro oligodendrogenesis at an expense of astrogenesis by yet unknown mechanisms (Rivera et al. 2006, Jadasz et al. 2013; 2018, Rivera et al., 2019). In the present study, we demonstrate that aNSCs pre-treated with MSC secretomes for different periods in vitro preferentially differentiate to oligodendrocytic cells in vivo after transplantation into the adult rat spinal cord. Analysis of different time points after transplantation revealed a stable survival rate of transplanted aNSCs and an emphasized pro-oligodendroglial differentiation in response to MSC secreted factors. MSC derived secretomes were then analyzed by mass spectrometry-based proteomics and label-free quantification to identify secreted proteins contributing to oligodendroglial lineage fate determination. To exclude possible contaminants derived from dead cells or serum, our approach includes a comparison of the abundances of proteins present in MSC derived secretomes with corresponding proteins in cell lysates (Grube et al., 2018, Schira-Heinen et al., 2019).