Astrocyte-Derived Exosomes Treated With a Semaphorin 3A Inhibitor Enhance Stroke Recovery via Prostaglandin D2 Synthase

Kenichiro Hira, Yuji Ueno, Ryota Tanaka, Nobukazu Miyamoto, Kazuo Yamashiro, Toshiki Inaba, Takao Urabe, Hideyuki Okano, Nobutaka Hattori

Research output: Contribution to journalArticle

8 Citations (Scopus)


Background and Purpose- Exosomes play a pivotal role in neurogenesis. In the peri-infarct area after stroke, axons begin to regenerate but are inhibited by astrocyte scar formation. The direct effect and underlying molecular mechanisms of astrocyte-derived exosomes on axonal outgrowth after ischemia are not known. Methods- Using a semaphorin 3A (Sema3A) inhibitor, we explored neuronal signaling during axonal outgrowth after ischemia in rats subjected to middle cerebral artery occlusion and in cultured cortical neurons challenged with oxygen-glucose deprivation. Furthermore, we assessed whether this inhibitor suppressed astrocyte activation and regulated astrocyte-derived exosomes to enhance axonal outgrowth after ischemia. Results- In rats subjected to middle cerebral artery occlusion, we administered a Sema3A inhibitor into the peri-infarct area from 7 to 21 days after occlusion. We found that phosphorylated high-molecular weight neurofilament-immunoreactive axons were increased, glial fibrillary acidic protein-immunoreactive astrocytes were decreased, and functional recovery was promoted at 28 days after middle cerebral artery occlusion. In cultured neurons, the Sema3A inhibitor decreased Rho family GTPase 1, increased R-Ras, which phosphorylates Akt and glycogen synthase kinase 3β (GSK-3β), selectively increased phosphorylated GSK-3β in axons, and thereby enhanced phosphorylated high-molecular weight neurofilament-immunoreactive axons after oxygen-glucose deprivation. In cultured astrocytes, the Sema3A inhibitor suppressed activation of astrocytes induced by oxygen-glucose deprivation. Exosomes secreted from ischemic astrocytes treated with the Sema3A inhibitor further promoted axonal elongation and increased prostaglandin D2 synthase expression on microarray analysis. GSK-3β+ and prostaglandin D2 synthase+ neurons were robustly increased after treatment with the Sema3A inhibitor in the peri-infarct area. Conclusions- Neuronal Rho family GTPase 1/R-Ras/Akt/GSK-3β signaling, axonal GSK-3β expression, and astrocyte-derived exosomes with prostaglandin D2 synthase expression contribute to axonal outgrowth and functional recovery after stroke.

Original languageEnglish
Pages (from-to)2483-2494
Number of pages12
Issue number10
Publication statusPublished - 2018 Oct 1



  • astrocytes
  • axon
  • exosomes
  • neurons
  • semaphorin 3A
  • stroke

ASJC Scopus subject areas

  • Clinical Neurology
  • Cardiology and Cardiovascular Medicine
  • Advanced and Specialised Nursing

Cite this

Hira, K., Ueno, Y., Tanaka, R., Miyamoto, N., Yamashiro, K., Inaba, T., Urabe, T., Okano, H., & Hattori, N. (2018). Astrocyte-Derived Exosomes Treated With a Semaphorin 3A Inhibitor Enhance Stroke Recovery via Prostaglandin D2 Synthase. Stroke, 49(10), 2483-2494.