Our results revealed that the IRF5 mRNA level in sorted microglia increased at 3 days of stroke; whereas IRF4 mRNA level exhibited biphasic increases, with a transient rise at 24 h and a peak at 10 days.
Our results suggest a central role for interferon regulatory factor 4-positive IL-23-producing conventional DCs in the IL-17-dependent secondary tissue damage in stroke.
Interferon regulatory factor-5 (IRF5) and IRF4 regulate M1 and M2 activation of macrophages, respectively, in peripheral inflammation; but it is unknown whether IRF5/IRF4 are also involved in cerebral inflammatory responses to stroke and whether age-related differences of the IRF5/IRF4 signaling exist in ischemic brain.
Integrative transcriptional and cell survival analyses showed that IRF4 functions mechanistically as a transcription activator of serum response factor (SRF) crucial to salvage neurons during stroke.