One-step RT-qPCR identified a selective catalytic p300/CBP inhibitor A-485 that decreased LPS-stimulated macrophage Il1β production. (A) Flow chart of the high-throughput screening assay for small-molecule inhibitors of macrophage activation and cytokine expression. (B) Results of high-throughput screening using a library containing 50 small-molecule probes. Inhibitors highlighted by dashed line in red are categorized as p300/CBP inhibitors. (C) Effects of p300/CBP inhibitors. SGC-CBP30, CPI-673, and A-485 are inhibitors of p300/CBP, inhibiting the bromodomain (SGC-CBP30 and CPI-673) or the histone acetyltransferase domain (A-485). The RT-qPCR data were normalized to a reference gene, Gapdh, and are shown as mean ± SD based on three independent experiments.