Microglia-Derived Exosomal miR-223-3p Targets the RhoB-NF-κB-CCL11 Axis in Astrocytes and Relieves Neuronal Damage in Subarachnoid Hemorrhage.

Neuroinflammation mediated by reactive microglia and astrocytes is the primary pathological process of early brain injury (EBI) after subarachnoid hemorrhage (SAH). This study aimed to investigate the role of microglia-derived exosomes in astrocytic activation and neuronal damage in SAH. An SAH mouse model was generated via endovascular perforation. Following the administration of miR-223-3p-enriched microglia-derived exosomes or a CCL11 antibody (anti-CCL11), the neurological functions of mice were evaluated. Nissl staining and TUNEL staining were carried out to assess neuronal apoptosis. The activation of microglia and astrocytes was examined by immunofluorescence. Hemin-treated primary cultured microglia and astrocytes were then cocultured with miR-223-3p-enriched exosomes or anti-CCL11. Furthermore, the conditioned medium of the cells was collected and added to HT22 cells. The viability, ROS level, and degree of oxidative stress in HT22 cells were determined. The mechanism of miR-223-3p to target RhoB was verified via a dual-luciferase reporter gene assay. Reduced miR-223-3p expression was detected in SAH mice, whereas CCL11 and inflammatory cytokines (IL-1β, IL-6, TNF-α, and IL-18) were elevated. Microglia-derived exosomal miR-223-3p or anti-CCL11 significantly mitigated neurological deficits and neuronal damage, and relieved microglial and astrocytic activation in the SAH model. In vitro experiments revealed that hemin induced significant activation of microglia and astrocytes. MiR-223-3p-enriched exosomes or anti-CCL11 attenuated hemin-induced microglial and astrocytic activation and attenuated HT22 cell damage through the inhibition of ROS and oxidative stress. Mechanistic studies revealed that miR-223-3p targeted RhoB and inhibited the RhoB/NF-κB/CCL11 axis in astrocytes. Microglia-derived exosomal miR-223-3p relieves EBI after SAH through the inhibition of astrocytic activation via the RhoB-NF-κB-CCL11 pathway.