IFN-? Induces Histone 3 Lysine 27 Trimethylation in a Small Subset of Promoters to Stably Silence Gene Expression in Human Macrophages.

ABSTRACT: The mechanisms by which IFN-? activates expression of interferon-stimulated genes that have inflammatory and host defense functions are well understood. In contrast, little is known about how IFN-? represses gene expression. By using transcriptomic and epigenomic analysis, we found that stable repression of a small group of genes by IFN-? is associated with recruitment of the histone methyltransferase EZH2 and deposition of the negative mark histone 3 lysine 27 trimethylation (H3K27me3) at their promoters. Repressed genes included MERTK, PPARG, and RANK, which have anti-inflammatory functions and promote osteoclast differentiation. Gene repression and H3K27me3 persisted after IFN-? signaling was terminated, and these silenced genes were no longer responsive to glucocorticoids, IL-4, and M-CSF. These results identify cytokine-induced H3K27 trimethylation as a mechanism that stabilizes gene silencing in macrophages. IFN-?-induced macrophage activation is thus reinforced by a chromatin-based mechanism that blocks anti-inflammatory and opposing pathways.

SUBMITTER: Qiao Y 

PROVIDER: S-EPMC5079287 | biostudies-literature | 2016 Sep

REPOSITORIES: biostudies-literature