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Analysis of the immune and astrocytic cell fraction 12h after cortical injury in Sema4B knockout mice

ABSTRACT: After central nervous system injury, a rapid neuroinflammatory response is induced. This response can be both beneficial and detrimental to neuronal survival in the first few days and increase the risk for neurodegeneration if it persists. Semaphorin4B (Sema4B), a transmembrane protein primarily expressed by cortical astrocytes, has been shown to play a role in neuronal cell death following injury. Our study shows that neuroinflammation is attenuated in Sema4B knockout mice and microglia/macrophage activation is reduced after cortical stab wound injury. In vitro, recombinant Sema4B enhances the activation of microglia following injury, suggesting astrocytic Sema4B functions as a ligand. Moreover, injury-induced activation of microglia is attenuated in the presence of Sema4B knockout astrocytes compared to heterozygous astrocytes. In vitro, experiments indicate Plexin-B2 is the Sema4B receptor on microglia. Consistent with this, microglia-specific Plexin-B2 knockout mice, similar to Sema4B knockout mice, also show a reduction in microglial activation after cortical injury. Finally, in Sema4B/Plexin-B2 double heterozygous mice, microglial activation is also reduced after injury, thus supporting the idea that both Sema4B and Plexin-B2 are part of the same signaling pathway. Taken together, we propose a model in which following injury, astrocytic Sema4B enhances the pro-inflammatory response of microglia/macrophages via Plexin-B2, leading to increased neuroinflammation.

ORGANISM(S): Mus musculus

PROVIDER: GSE230069 | GEO | 2024/02/28

REPOSITORIES: GEO

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