IRF5 promotes inflammatory macrophage polarization and TH1-TH17 responses

Macrophages are functionally highly plastic, but the transcriptional control of this process is only partially understood. Udalova and colleagues demonstrate that the transcription factor IRF5 controls the plasticity of M1 macrophages in both mice and humans. Polymorphisms in the gene encoding the transcription factor IRF5 that lead to higher mRNA expression are associated with many autoimmune diseases. Here we show that IRF5 expression in macrophages was reversibly induced by inflammatory stimuli and contributed to the plasticity of macrophage polarization. High expression of IRF5 was characteristic of M1 macrophages, in which it directly activated transcription of the genes encoding interleukin 12 subunit…