Extracellular vesicles from bone marrow stromal cells reduce the impact of stroke on glial cell activation and blood brain‐barrier permeability via a putative miR‐124/PRX1 signalling pathway

Abstract Ischaemic stroke (IS) is a cerebrovascular disease caused by cerebral infarction and cerebral artery occlusion. In this study, we proposed that EVs from bone marrow stromal cells (BMSCs) could reduce the impact of stroke by reducing the resultant glial cell activation and blood–brain barrier (BBB) leak. We furthermore investigated some of the signalling mechanisms. The transient middle cerebral artery occlusion (t‐MCAO) mouse model was established. The behavioural deficits and neuronal damage were verified using Bederson's scale and the 28‐point neurological score. The area of cerebral infarction was detected. The expressions of astrocytes/microglia markers and BBB permeability were evaluated by 2,3,5‐triphenyltetrazolium chloride (TTC) staining. The internalization of EVs by astrocytes/microglia in the peripheral area was detected by fluorescence labelling. The expressions of astrocyte/microglia markers were measured by RT‐qPCR. Levels of TNF‐α and IL‐1β in microglia were detected by ELISA. BBB permeability was evaluated. The downstream target genes and pathway of miR‐124 were analysed. Microglia/astrocytes were treated by oxygen–glucose deprivation reoxygenation (OGD/R). OGD/R microglia/astrocyte conditioned medium was used to culture bEnd.3 cells. The transendothelial electric resistance (TEER) of bEnd.3 cells was measured, and BBB permeability was characterized. Our results suggested that EVs from BMSCs can indeed reduce the extent of stroke‐mediated damage and evidenced that these effects are mediated via expression of the non‐coding RNA, miR‐124 that may act via the peroxiredoxin 1 (PRX1). Our results provided further motivation to pursue the use of modified EVs as a treatment option for neurological diseases.