Functional analysis of secreted tissue inhibitor of metalloproteinases-1 from adult human neural stem cells (ahNSCs) for regeneration and neuroprotection

The adult human neural stem cell (ahNSC)-conditioned medium (CM) contains various secreted factors that promote tissue repair and neuroprotection. This study aimed to identify the key secreted proteins in ahNSC-CM and investigate the role of tissue inhibitor of metalloproteinases-1 (TIMP-1) in wound healing, angiogenesis, and neuroprotection against oxygen-glucose deprivation. Cytokine array and liquid chromatography–tandem mass spectrometry analysis of ahNSC-CM revealed that monocyte chemoattractant protein-1 (MCP-1) and TIMP-1 were highly abundant. Enzyme-linked immunosorbent assay confirmed the enrichment of both in ahNSC-CM. Recombinant human TIMP-1 promoted wound closure and angiogenesis, whereas neutralizing TIMP-1 in ahNSC-CM attenuated these effects, with wound healing involving the extracellular signal-regulated kinases 1 and 2 and protein kinase B pathways. Furthermore, ahNSC-CM protected neurons from oxygen-glucose deprivation-induced apoptosis, and this neuroprotective effect was partially reversed by TIMP-1 neutralization, potentially through the modulation of B-cell lymphoma 2 and B-cell lymphoma 2-associated X protein expression. Consistent with findings in ahNSCs, where monocyte chemoattractant protein-1 is highly expressed and contributes to pro-angiogenic effects, our study highlights the importance of secreted factors such as TIMP-1 in the therapeutic potential of ahNSC-CM. These findings suggest that TIMP-1 is a significant component of ahNSC-CM and contributes to its regenerative and neuroprotective properties.