Abstract
Mesenchymal stem cells (MSCs) play important roles in tissue repair and regeneration, such as the induction of angiogenesis, particularly under hypoxic conditions. However, the molecular mechanisms underlying hypoxic MSC activation remain largely unknown. MSC-derived extracellular vesicles (EVs) are vital mediators of cell-to-cell communication and can be directly utilized as therapeutic agents for tissue repair and regeneration. Here, we explored the effects of EVs from human hypoxic olfactory mucosa MSCs (OM-MSCs) on angiogenesis and its underlying mechanism. EVs were isolated from normoxic (N) OM-MSCs (N-EVs) and hypoxic (H) OM-MSCs (H-EVs) using differential centrifugation and identified by transmission electron microscopy and flow cytometry. In vitro and in vivo, both types of OM-MSC-EVs promoted the proliferation, migration, and angiogenic activities of human brain microvascular endothelial cells (HBMECs). In addition, angiogenesis-stimulatory activity in the H-EV group was significantly enhanced compared to the N-EV group. MicroRNA profiling revealed a higher abundance of miR-612 in H-EVs than in N-EVs, while miR-612 inactivation abolished the N-EV treatment benefit. To explore the roles of miR-612, overexpression and knock-down experiments were performed using a mimic and inhibitor or agomir and antagomir of miR-612. The miR-612 target genes were confirmed using the luciferase reporter assay. Gain- and loss-of-function studies allowed the validation of miR-612 (enriched in hypoxic OM-MSC-EVs) as a functional messenger that stimulates angiogenesis and represses the expression of TP53 by targeting its 3′-untranslated region. Further functional assays showed that hypoxic OM-MSC-EVs promote paracrine Hypoxia-inducible factor 1-alpha (HIF-1α)-Vascular endothelial growth factor (VEGF) signaling in HBMECs via the exosomal miR-612-TP53-HIF-1α-VEGF axis. These findings suggest that hypoxic OM-MSC-EVs may represent a promising strategy for ischemic disease by promoting angiogenesis via miR-612 transfer.Graphical
Highlights
Over the past few years, the mesenchymal stem cell (MSC) therapy has attracted widespread attention for the treatment of ischemic disease, such as skin wound healing, peripheral and coronary vascular disease [1], cerebral infarction [2], and acute kidney ischemia injury [3]
H-extracellular vesicles (EVs) and normoxia-cultured OM-MSC derived EVs (N-EVs) were isolated from hypoxic and normoxic olfactory mucosa MSCs (OM-MSCs) and characterized using western (See figure on page.) Fig. 3 Hypoxia Leads to Changes in hypoxia OM-MSC derived EVs (H-EVs) and N-EVs micro RNAs (miRNAs) Profiles and miR-612 mediates the pro-angiogenic effects of olfactory mucosa (OM)-MSC-derived extracellular vesicles (MSC-EVs) on human brain microvascular endothelial cells (HBMECs)
G Cell viability at 6 h and 12 h was examined in HBMECs that were treated with EVs obtained from OM-MSCs that were pretreated with scramble (OM-MSC-EVsNC)or with EVs isolated from OM-MSCs that were pretreated with anti-miR-612 (OM-MSC-EVsanti-miR-612), (n = 5),***P < 0.001
Summary
Over the past few years, the mesenchymal stem cell (MSC) therapy has attracted widespread attention for the treatment of ischemic disease, such as skin wound healing, peripheral and coronary vascular disease [1], cerebral infarction [2], and acute kidney ischemia injury [3]. MSCs are tissue-derived cells with unique characteristics that include a self-renewing ability, multilineage differentiation potential, and immunomodulatory properties [4]. Studies in both animal and human settings have demonstrated the therapeutic potential of MSCs in the treatment of a range of disorders, including ischemic disease. Extracellular vesicles (EVs) have been reported to be essential paracrine components of MSCs, and they may offer a suitable alternative to cell-based therapies. MSC-derived extracellular vesicles (MSCEVs) possess an angiogenic function and are highly effective for treating ischemic diseases.
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