Bone marrow mesenchymal stem cell-derived exosomes (BMSC-Exos) have been shown to promote angiogenesis after ischemic stroke, in which microRNAs (miRs) are believed to play an important role in exosome-mediated therapeutic effects, though the mechanism is still not clear. In this study, a series of molecular biological and cellular assays, both in vitro and in vivo, were performed to elucidate the role of exosomal miR-486 in angiogenesis following cerebral ischemic and its molecular mechanisms. Our results revealed that BMSC-Exos significantly improved neurological function and increased microvessel density in ischemic stroke rats. In vitro assays showed that BMSC-Exos promoted the proliferation, migration, and tube formation ability of oxygen–glucose deprivation/reoxygenation (OGD/R) injured rat brain microvascular endothelial cells (RBMECs). Importantly, BMSC-Exos increased the expression of miR-486 and phosphorylated protein kinase B (p-Akt) and down-regulated the protein level of phosphatase and tensin homolog (PTEN) in vivo and in vitro. Mechanistic studies demonstrated that transfection with miR-486 mimic enhanced RBMECs angiogenesis and increased p-Akt expression, while inhibited PTEN expression. On the other hand, the miR-486 inhibitor induced an opposite effect, which could be blocked by PTEN siRNA. It was thus concluded that exosomal miR-486 from BMSCs may enhance the functional recovery by promoting angiogenesis following cerebral ischemic injury, which might be related to its regulation of the PTEN/Akt pathway.

Leading to more and more deaths and disabilities, stroke has become a serious threat to human health. What’s more, few effective drugs are available in clinic till now. In this research, we prepared a novel neuroprotective nanoformation (OEA–SPC NPs) via the combination of the nanoparticle drug delivery system with the endogenous N-oleoylethanolamine (OEA). By forming hydrogen bond between OEA and the carrier—soybean phosphatidylcholine (SPC), the form of OEA was turned into amorphus state when loading to the nanoparticles, which greatly improved its bioavailability. Then the following systematic experiments revealed the efficient neuroprotective effect of OEA–SPC NPs in vivo. Compared with the MCAO group, the cerebral infarct volume was reduced by 81.1%, and the edema degree by 78.4% via the oral administration of OEA–SPC NPs. And the neurological deficit scores illustrated that the MCAO rats treated with OEA–SPC NPs exhibited significantly less neurological dysfunction. The Morris water maze test indicated that the spatial learning and memory of cerebral ischemia model rats were almost recovered to the normal level. Besides, the OEA–SPC NPs could inhibit the inflammation of reperfusion to a very slight level. These results suggest that the OEA–SPC NPs have a great chance to be a potential anti-stroke formation for clinic application and actually bring hope to thousands of stroke patients.

Ischemic stroke (IS) remains a challenge in clinical treatment due to limited therapeutic options. While artemisinin (ART), an antimalarial drug, shields against acute IS via anti-inflammatory, antioxidant, and anti-apoptotic properties, the long-term benefits and specific underlying mechanisms have not been fully elucidated. Here, we investigate whether ART ameliorates IS injury and promotes neurogenesis by activating the peroxisome proliferator-activated receptor γ (PPARγ)-dependent M2 microglial polarization. The experimental models included transient middle cerebral artery occlusion/reperfusion (MCAO/R) in rats and oxygen-glucose deprivation/reoxygenation (OGD/R) in primary microglial cultures to simulate IS. The therapeutic effects of ART were evaluated by neurological functions and infarct volume. PPARγ inhibitor T0070907 (T007) was intraperitoneally injected 24 h following MCAO/R at a dose of 2 mg/kg in vivo and a concentration of 10 μM for 30 min before OGD in vitro. We utilized real-time quantitative polymerase chain reaction (RT-qPCR) along with Western blot analyses to detect the microglia markers and PPARγ. The proliferation and differentiation of neural stem cells (NSCs) both in vivo and in vitro were assessed via immunofluorescence labeling. The neurogenic potential of ART-treated microglia was investigated by conditioned medium. The levels of brain-derived growth factor (BDNF) and insulin-like growth factor-1 (IGF-1) in microglia were measured by immunofluorescence staining and enzyme-linked immunosorbent assay (ELISA). ART treatment significantly alleviated short- and long-term neurological deficits and reduced cerebral infarct volume in rats with IS. Experiments conducted both in vivo and in vitro experiments illustrated that ART directed microglia away from the pro-inflammatory M1 state towards the anti-inflammatory M2 state, enhanced neurogenesis, and upregulated the expression of PPARγ, BDNF, and IGF-1. In addition, the conditioned medium from ART-exposed microglia stimulated the proliferation and neuronal differentiation of primary NSCs. However, these positive effects were effectively counteracted by the use of PPARγ inhibitor T0070907 (T007). Our findings demonstrate that ART ameliorates IS injury and promotes neurogenesis mainly through PPARγ-mediated microglia M2 polarization. Therefore, ART can be considered a potential therapeutic drug for IS.

Stroke is a prominent contributor to mortality and impairment on a global scale. Ischemic stroke accounts for approximately 80% of stroke cases and is caused by occlusion of cerebral blood vessels. Enhancing neurogenesis through the modulation of the neural stem cell niche in the adult brain is a promising therapeutic strategy for individuals afflicted with ischemic stroke. Neurogenesis results in the generation of newborn neurons that serve as replacements for deceased neural cells within the ischemic core, thereby playing a significant role in the process of neural restoration subsequent to cerebral ischemia. Research has shown that activation of the Wnt/β-catenin pathway can augment neurogenesis following cerebral ischemia, suggesting that this pathway is a potentially beneficial therapeutic target for managing ischemic stroke. This review provides an extensive analysis of the current knowledge regarding the involvement of the Wnt/β-catenin pathway in promoting neurogenesis, thereby offering a promising avenue for therapeutic intervention in the context of ischemic stroke or other neurological impairments.

The interaction between infiltrating immune cells and brain-resident cells is critical for inducing an inflammatory response to ischemic stroke. However, the direct effects of CD11b⁺CD45^int microglia in the brain on infiltrating CD11b⁺CD45^highLy6G^- monocytes/macrophages (Mos/MΦs) and the precise molecular mechanisms underlying these effects after acute ischemic stroke (AIS) remain unknown. Here, ischemia-induced microglial peroxisome proliferator-activated receptor-alpha (PPARα) downregulation was found to be critical for enhancing the inflammatory response and exacerbating ischemic brain injury by priming peripheral pro-inflammatory Mo/MΦ infiltration. The targeted microglial PPARα signal exerted neuroprotective effects on ischemic stroke by protecting blood-brain barrier (BBB) integrity and inhibiting the infiltration of innate immune cells. Furthermore, overexpression of microglia-specific PPARα exerted neuroprotective effects by enhancing the interleukin (IL)-4 signal-mediated crosstalk of microglia-MΦs. Therefore, our study reveals that ischemia-induced microglial PPARα deficiency expands the inflammatory response and exacerbates ischemic brain injury by enhancing the interaction with infiltrating peripheral Mos/MΦs and suggests that targeting microglial PPARα is a potential therapeutic strategy for improving acute cerebral ischemic injury.