Click chemistry extracellular vesicle/peptide/chemokine nanocarriers for treating central nervous system injuries

Central nervous system(CNS)injuries,including stroke,traumatic brain injury,and spinal cord injury,are essential causes of death and long-term disability and are difficult to cure,mainly due to the limited neuron regeneration and the glial scar formation.Herein,we apply extracellular vesicles(EVs)secreted by M2 microglia to improve the differentiation of neural stem cells(NSCs)at the injured site,and simultaneously modify them with the injured vascular targeting peptide(DA7R)and the stem cell recruiting factor(SDF-1)on their surface via copper-free click chemistry to recruit NSCs,inducing their neuronal differentiation,and serving as the nanocarriers at the injured site(Dual-EV).Results prove that the Dual-EV could target human umbilical vascular endothelial cells(HUVECs),recruit NSCs,and promote the neuronal differentiation of NSCs in vitro.Furthermore,10 miRNAs are found to be upregulated in Dual-M2-EVs compared to Dual-M0-EVs via bioinformatic analysis,and further NSC differentiation experiment by flow cytometry reveals that among these miRNAs,miR30b-3p,miR-222-3p,miR-129-5p,and miR-155-5p may exert effect of inducing NSC to differentiate into neurons.In vivo experiments show that Dual-EV nanocarriers achieve improved accumulation in the ischemic area of stroke model mice,potentiate NSCs recruitment,and increase neurogenesis.This work provides new insights for the treatment of neuronal regeneration after CNS injuries as well as endogenous stem cells,and the click chemistry EV/peptide/chemokine and related nanocarriers for improving human health.

Plasma from healthy donors protects blood-brain barrier integrity via FGF21 and improves the recovery in a mouse model of cerebral ischaemia

Background Healthy plasma therapy reverses cognitive deficits and promotes neuroplasticity in ageing brain disease.However,whether healthy plasma therapy improve blood-brain barrier integrity after stroke remains unknown.Methods Here,we intravenously injected healthy female mouse plasma into adult female ischaemic stroke C57BL/6 mouse induced by 90 min transient middle cerebral artery occlusion for eight consecutive days.Infarct volume,brain atrophy and neurobehavioural tests were examined to assess the outcomes of plasma treatment.Cell apoptosis,blood-brain barrier integrity and fibroblast growth factor 21 knockout mice were used to explore the underlying mechanism.Results Plasma injection improved neurobehavioural recovery and decreased infarct volume,brain oedema and atrophy after stroke.Immunostaining showed that the number of transferase dUTP nick end labelling+/NeuN+cells decreased in the plasma-injected group.Meanwhile,plasma injection reduced ZO-1,occluding and claudin-5 tight junction gap formation and IgG extravasation at 3 days after ischaemic stroke.Western blot results showed that the FGF21 expression increased in the plasma-injected mice.However,using FGF21 knockout mouse plasma injecting to the ischaemic wild-type mice diminished the neuroprotective effects.Conclusions Our study demonstrated that healthy adult plasma treatment protected the structural and functional integrity of blood-brain barrier,reduced neuronal apoptosis and improved functional recovery via FGF21,opening a new avenue for ischaemic stroke therapy.