IRF8 Is a Critical Transcription Factor for Transforming Microglia into a Reactive Phenotype

Takahiro Masuda, Makoto Tsuda, Ryohei Yoshinaga, Hidetoshi Tozaki-Saitoh, Keiko Ozato, Tomohiko Tamura, Kazuhide Inoue

Research output: Contribution to journalArticlepeer-review

201 Citations (Scopus)


Microglia become activated by multiple types of damage in the nervous system and play essential roles in neuronal pathologies. However, how microglia transform into reactive phenotypes is poorly understood. Here, we identify the transcription factor interferon regulatory factor 8 (IRF8) as a critical regulator of reactive microglia. Within the spinal cord, IRF8 expression was normally low; however, the expression was markedly upregulated in microglia, but not in neurons or astrocytes, after peripheral nerve injury (PNI). IRF8 overexpression in cultured microglia promoted the transcription of genes associated with reactive states; conversely, IRF8 deficiency prevented these gene expressions in the spinal cord following PNI. Furthermore, IRF8-deficient mice were resistant to neuropathic pain, a common sequela of PNI, and transferring IRF8-overexpressing microglia spinally to normal mice produced pain. Therefore, IRF8 may activate a program of gene expression that transforms microglia into a reactive phenotype. Our findings provide a newly observed mechanism for microglial activation.

Original languageEnglish
Pages (from-to)334-340
Number of pages7
JournalCell Reports
Issue number4
Publication statusPublished - Mar 19 2012

All Science Journal Classification (ASJC) codes

  • Biochemistry, Genetics and Molecular Biology(all)


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