Small extracellular vesicles secreted by human iPSC-derived MSC enhance angiogenesis through inhibiting STAT3-dependent autophagy in ischemic stroke.

BACKGROUND: Small extracellular vesicles (sEV) secreted by mesenchymal stem cells (MSC) derived from human induced pluripotent stem cells (iPSC, iMSC-sEV) are considered to have great potential in treating ischemic diseases. Angiogenesis play an important role in post-stroke recovery. However, no studies have yet been conducted to systemically examine the effect and the underlying mechanism of iMSC-sEV on angiogenesis under brain ischemia conditions. METHODS: Ischemic stroke model was performed in rats induced by middle cerebral artery occlusion (MCAO), and the pro-angiogenic capacity of iMSC-sEV was measured. The in vitro effects of iMSC-sEV on the migration and tube formation of endothelial cells were investigated, respectively. Autophagy and autophagy-related signaling pathway were detected in vivo and in vitro. RESULTS: We found that iMSC-sEV significantly reduced infarct volume, enhanced angiogenesis, and alleviated long-term neurological deficits in rats after stroke. We also demonstrated that iMSC-sEV increased migration and tube formation of endothelial cells in vitro. A further mechanism study revealed that the pro-angiogenic effect of iMSC-sEV was correlated with a reduction in autophagy. Furthermore, iMSC-sEV significantly activated signal transducer and activator of transcription 3 (STAT3), and suppression of STAT3 abolished iMSC-sEV-induced inhibition of autophagy and promotion of angiogenesis in vivo and in vitro. CONCLUSIONS: Taken together, our data indicate that iMSC-sEV promote angiogenesis after ischemic stroke, potentially, by inhibiting autophagy, a process that is partially dependent on STAT3 activation.

Exosomes from human urine-derived stem cells enhanced neurogenesis via miR-26a/HDAC6 axis after ischaemic stroke.

Endogenous neurogenesis holds promise for brain repair and long-term functional recovery after ischaemic stroke. However, the effects of exosomes from human urine-derived stem cells (USC-Exos) in neurogenesis remain unclear. This study aimed to investigate whether USC-Exos enhanced neurogenesis and promoted functional recovery in brain ischaemia. By using an experimental stroke rat model, we found that intravenous injection of USC-Exos enhanced neurogenesis and alleviated neurological deficits in post-ischaemic stroke rats. We used neural stem cells (NSCs) subjected to oxygen-glucose deprivation/reoxygenation (OGD/R) as an in vitro model of ischaemic stroke. The in vitro results suggested that USC-Exos promoted both proliferation and neuronal differentiation of NSCs after OGD/R. Notably, a further mechanism study revealed that the pro-neurogenesis effects of USC-Exos may be partially attributed to histone deacetylase 6 (HDAC6) inhibition via the transfer of exosomal microRNA-26a (miR-26a). Taken together, this study indicates that USC-Exos can be used as a novel promising strategy for brain ischaemia, which highlights the application of USC-Exos.

Embryonic Stem Cells-Derived Exosomes Endowed with Targeting Properties as Chemotherapeutics Delivery Vehicles for Glioblastoma Therapy.

Exosomes are nanosized membrane vesicles (30-100 nm) that can easily penetrate the blood-brain barrier, safely deliver therapeutic drugs, and be modified with target ligands. Embryonic stem cells (ESCs) provide abundant exosome sources for clinical application due to their almost unlimited self-renewal. Previous studies show that exosomes secreted by ESCs (ESC-exos) have antitumor properties. However, it is not known whether ESC-exos inhibit glioblastoma (GBM) growth. In this study, the anti-GBM effect of ESC-exos is confirmed and then c(RGDyK)-modified and paclitaxel (PTX)-loaded ESC-exos, named cRGD-Exo-PTX are prepared. It is then investigated whether the engineered exosomes deliver more efficiently to GBM cells versus free drug alone and drug-loaded ESC-exos using an in vitro GBM model and in vivo subcutaneous and orthotopic xenografts model. The results show that cRGD-Exo-PTX significantly improves the curative effects of PTX in GBM via enhanced targeting. These data indicate that ESC-exos are potentially powerful therapeutic carriers for GBM and could have utility in many other diseases.

Extracellular Vesicles Secreted by Human Urine-Derived Stem Cells Promote Ischemia Repair in a Mouse Model of Hind-Limb Ischemia.

BACKGROUND/AIMS: Our previous studies have shown that human urine-derived stem cells (USCs) have great potential as a cell source for cytotherapy and tissue engineering and that extracellular vesicles (EVs) secreted by USCs (USCs-EVs) can prevent diabetes-induced kidney injury in an animal model. The present study was designed to evaluate the effects of USCs-EVs on ischemia repair. METHODS: USCs-EVs were isolated and purified by a battery of centrifugation and filtration steps. The USCs-EVs were then characterized by transmission electron microscopy, western blot and tunable resistive pulse sensing techniques. After intramuscularly transplanting USCs-EVs into an ischemic mouse hind-limb, we observed the therapeutic effects of USCs-EVs on perfusion by laser doppler perfusion imaging, angiogenesis and muscle regeneration by histology and immunohistochemistry techniques over 21 days. We subsequently tested whether USCs-EVs can induce the proliferation of a human microvascular endothelial cell line HMEC-1 and a mouse myoblast cell line C2C12 by cell counting kit 8 assay in vitro. Meanwhile, the potential growth factors in the USCs-EVs and supernatants of the USCs cultures were detected by enzyme-linked immunosorbent assay. RESULTS: The USCs-EVs were spherical vesicles with a diameter of 30-150 nm and expressed exosomal markers, such as CD9, CD63 and Tsg101. Ischemic limb perfusion and function were markedly increased in the hind-limb ischemia (HLI) model after USCs-EVs administration. Moreover, angiogenesis and muscle regeneration levels were significantly higher in the USCs-EVs treatment group than in the PBS group. The in vitro experiments showed that USCs-EVs facilitated HMEC-1 and C2C12 cell proliferation in a dose-dependent manner. CONCLUSIONS: These results revealed for the first time that USCs-EVs efficiently attenuate severe hind-limb ischemic injury and represent a novel therapy for HLI.

Oxymatrine Inhibits Proliferation and Migration While Inducing Apoptosis in Human Glioblastoma Cells.

Oxymatrine (OMT), an alkaloid derived from the traditional Chinese medicine herb Sophora flavescens Aiton, has been shown to exhibit anticancer properties on various types of cancer cells. In this study, we investigate the anticancer properties of OMT on human glioblastoma (GBM) cells and evaluate their underlying mechanisms. MTT assays were performed and demonstrated that OMT significantly inhibits the proliferation of GBM cells. Flow cytometry suggested that OMT at a concentration of 10-5 M may induce apoptosis in U251 and A172 cells. Western blot analyses demonstrated a significant increase in the expression of Bax and caspase-3 and a significant decrease in expression of Bcl-2 in both U251 and A172 cells. Additionally, OMT was found by transwell and high-content screening assays to decrease the migratory ability of the evaluated GBM cells. These findings suggest that the antitumor effects of OMT may be the result of inhibition of cell proliferation and migration and the induction of apoptosis by regulating the expression of apoptosis-associated proteins. OMT may represent a novel anticancer therapy for the treatment of GBM.