The NACHT, LRR and PYD domains-containing protein 3 (NLRP3) inflammasome is a multimeric, cytoplasmic, protein complex that regulates maturation and secretion of interleukin (IL)-1β, a potent pro-inflammatory cytokine. Critical to host defense against pathogens, IL-1β amplifies early innate immune responses by activating transcription of numerous other cytokines and chemokines. Excessive IL-1β is associated with poor outcomes in inflammatory illnesses, such as sepsis and the acute respiratory distress syndrome (ARDS). Tight regulation of this signaling axis is vital, but little is known about mechanisms to limit excessive inflammasome activity. Here we identify the deubiquitinase STAM-binding protein (STAMBP) as a negative regulator of the NLRP3 inflammasome. In monocytes, knockout of STAMBP by CRISPR/Cas9 gene editing increased expression of numerous cytokines and chemokines in response to Toll-like receptor (TLR) agonists or bacterial lipopolysaccharide (LPS). This exaggerated inflammatory response was dependent on IL-1β signaling, and STAMBP knockout directly increased release of IL-1β with TLR ligation. While STAMBP does not modulate NLRP3 protein abundance, cellular depletion of the deubiquitinase increased NLRP3 K63 chain polyubiquitination resulting in increased NLRP3 inflammasome activation. These findings describe a unique mechanism of non-degradative ubiquitination of NLRP3 by STAMBP to limit excessive inflammasome activation and to reduce injurious IL-1β signaling.

含有 NACHT、LRR 和 PYD 结构域的蛋白 3 (NLRP3) 炎症小体是一种多聚体细胞质蛋白复合物，可调节白细胞介素 (IL)-1β 的成熟和分泌，白细胞介素 (IL)-1β 是一种有效的促炎细胞因子。IL-1β 对宿主防御病原体至关重要，它通过激活许多其他细胞因子和趋化因子的转录来放大早期先天免疫反应。过多的 IL-1β 与脓毒症和急性呼吸窘迫综合征 (ARDS) 等炎症性疾病的不良预后相关。严格调节该信号轴至关重要，但对限制过度炎性体活动的机制知之甚少。在这里，我们将去泛素化酶 STAM 结合蛋白 (STAMBP) 鉴定为 NLRP3 炎性体的负调节因子。在单核细胞中，通过 CRISPR/Cas9 基因编辑敲除 STAMBP 可增加多种细胞因子和趋化因子的表达，以响应 Toll 样受体 (TLR) 激动剂或细菌脂多糖 (LPS)。这种夸大的炎症反应依赖于 IL-1β 信号，而 STAMBP 敲除直接增加了 IL-1β 与 TLR 连接的释放。虽然 STAMBP 不调节 NLRP3 蛋白丰度，但去泛素化酶的细胞耗竭增加了 NLRP3 K63 链多聚泛素化，导致 NLRP3 炎性体激活增加。这些发现描述了 STAMBP 对 NLRP3 进行非降解泛素化以限制过度炎性体激活并减少有害的 IL-1β 信号传导的独特机制。这种夸大的炎症反应依赖于 IL-1β 信号，而 STAMBP 敲除直接增加了 IL-1β 与 TLR 连接的释放。虽然 STAMBP 不调节 NLRP3 蛋白丰度，但去泛素化酶的细胞耗竭增加了 NLRP3 K63 链多聚泛素化，导致 NLRP3 炎性体激活增加。这些发现描述了 STAMBP 对 NLRP3 进行非降解泛素化以限制过度炎性体激活并减少有害的 IL-1β 信号传导的独特机制。这种夸大的炎症反应依赖于 IL-1β 信号，而 STAMBP 敲除直接增加了 IL-1β 与 TLR 连接的释放。虽然 STAMBP 不调节 NLRP3 蛋白丰度，但去泛素化酶的细胞耗竭增加了 NLRP3 K63 链多聚泛素化，导致 NLRP3 炎性体激活增加。这些发现描述了 STAMBP 对 NLRP3 进行非降解泛素化以限制过度炎性体激活并减少有害的 IL-1β 信号传导的独特机制。