Genome-wide binding profiles of JUNB in unstimulated HoxER-PU.1 WT and PU.1 KO neutrophils

Neutrophils are essential first line defense cells against invading pathogens, yet their inappropriate activation contributes to immunological diseases and can cause collateral tissue damage. However, neutrophil-intrinsic mechanisms adjusting an appropriate inflammatory response are unknown. Herein, we conditionally deleted PU.1, a key myeloid transcription factor, from the neutrophils of mice undergoing fungal infection, and then performed comprehensive epigenomic profiling. We find that a major function of PU.1 is to restrain the neutrophils' immune response by broadly suppressing genomic enhancer outputs via recruiting histone deacetylase activity, thereby limiting the immune-stimulatory AP1-transcription factor JUNB from entering chromatin. Thus, PU.1 acts as rheostat of the inflammatory chromatin state, safeguarding the neutrophil epigenome from undergoing uncontrolled activation prior to pathogenic stimulation. Overall design: Examination of JUNB occupany in unstimulated HoxER-PU.1 WT and PU.1 KO neutrophils by deep sequencing in duplicates.

中性粒细胞是抵御入侵病原体的关键第一道防线免疫细胞，但其异常活化可诱发免疫性疾病，并引发附带组织损伤。然而，调控中性粒细胞产生适度炎症应答的固有机制目前仍不明晰。
本研究对受真菌感染小鼠的中性粒细胞条件性敲除关键髓系转录因子PU.1，随后开展全面表观基因组分析。研究发现，PU.1的核心功能之一是通过招募组蛋白去乙酰化酶活性，广泛抑制基因组增强子的调控输出，从而抑制中性粒细胞的免疫应答，进而限制免疫刺激性AP1转录因子JUNB结合染色质。据此，PU.1可作为炎症染色质状态的变阻器，保护中性粒细胞表观基因组免受病原体刺激前的不受控激活。
整体实验设计：通过两次重复的深度测序，检测未受刺激的HoxER-PU.1野生型（WT）与PU.1基因敲除（KO）中性粒细胞中JUNB的染色质结合占有率。