Fig. 3 |. epigenomic regulation links type I IFN signaling to induction of inflammatory non-ISgs.
Stimulation of macrophages with TNF leads to transient expression of TNF-target genes encoding inflammatory mediators, such as IL6 and TNF, followed by a state of tolerance in which signaling responses to TLR ligands are strongly suppressed, and chromatin is not activated (not depicted). In contrast to tolerization with TNF alone, co-stimulation with TNF plus IFN-α results in coordinate binding of IRFs and NF-κB, increased chromatin accessibility and increased positive histone marks, most notably H3K4me3 (top right). These genes are thereby bookmarked with primed chromatin and subsequently exhibit a robust transcriptional response even to very weak proximal TLR-induced signals, such as those in TNF-tolerized cells on TLR stimulation (bottom right). TSS, transcription start site; ac, acetyl; Pol, polymerase.