(516d) Tissue Development of Pluripotent Stem Cell-Derived Neural Progenitor Aggregates Regulated By Human Mesenchymal Stem Cell Secretome

Neural progenitor cells (NPCs) derived from pluripotent stem cells (PSCs), including embryonic stem cells (ESCs) and induced PSCs, emerge as a promising tool for the potential treatment of various neurological diseases. Regulation of PSC-derived NPC microtissues is critical for the cell survival, proliferation, and differentiation both in vitro and in vivo. It is hypothesized that human mesenchymal stem cell (hMSC) secretomes promote PSC-derived NPC microtissue attachment, survival, proliferation, and migration through the modulation of PSC-NPC microenvironment. To test this hypothesis, PSC-derived NPC aggregates were replated in the presence of hMSC secretomes generated under hypoxia and normoxia. The adherent cell number, cells in S phase of cell cycle, and cell viability were significantly promoted in hMSC secretomes which were produced under normaxia or hypoxia. The migration length, neurite extension, and the yield of neural and glial differentiated cells were also increased. The hMSC secretomes were found to stimulate the endogenous secretion of extracellular matrices from PSC-derived NPC aggregates. Moreover, molecules regulating the signaling from fibroblast growth factor (FGF)-2, transforming growth factor (TGF)-β1, and brain-derived neurotrophic factor (BDNF) were identified to contribute to the cellular response through the pathway inhibition with PD173074, a FGFR1/FGFR3 inhibitor, SB431542, a SMAD2 inhibitor, and anti-proBDNF respectively. PSC-derived NPC aggregates in hypoxic hMSC secretome may represent a suitable combination to promote engraftment and neurogenesis in vivo.