Insight into the proteomic profiling of exosomes secreted by human OM-MSCs reveals a new potential therapy

Mesenchymal stromal cells (MSCs) have been used for the treatment of neuronal injury and neurodegenerative diseases. Their underlying mechanism may involve increased secretion of paracrine factors, which promotes tissue repair. Presently, exosomes have been regarded as important components of paracrine secretion and paracrine factors. MSC exosomes represent a promising opportunity to develop novel cell-free therapy approaches. In this study, exosomes from nasal olfactory mucosa MSCs (OM-MSCs) were extracted and purified using ultracentrifugation, resulting in exosome diameters of 40-130 nm. Similar to other exosomes, OM-MSC exosomes were CD63- and CD81-positive and calnexin-negative. Functionally, OM-MSC exosomes promoted human brain microvascular endothelial cell (HBMEC) proliferation and migration. The present study analyzed the OM-MSC exosome paracrine proteome. A total of 304 exosome-associated proteins were identified by LC-MS/MS, including plasminogen activator inhibitor 1 (SERPINE 1), insulin-like growth factor binding protein family members (IGFBP 4 and 5), epidermal growth factor receptor (EGFR), neurogenic locus notch homolog protein 2 (NOTCH 2), apolipoprotein E (APOE), and heat shock protein HSP90-beta (HSP90AB1). These molecules are known to be important in neurotrophic, angiogenesis, cell growth, differentiation, apoptosis, and inflammation and are highly correlated with the mechanism of tissue repair and neural restoration. These observations may provide a basis for further evaluation of OM-MSC exosome potential as a novel therapeutic modality.