MOE Key Laboratory of Gene Function and Regulation, Department of Gastroenterology and Guangzhou Institute of Pediatrics, Guangzhou Women and Children's Medical Center, School of Life Sciences, Sun Yat-sen University, Guangzhou, China.
MOE Key Laboratory of Gene Function and Regulation, Department of Gastroenterology and Guangzhou Institute of Pediatrics, Guangzhou Women and Children's Medical Center, School of Life Sciences, Sun Yat-sen University, Guangzhou, China; Guangdong Provincial Key Laboratory of Gastroenterology, Department of Gastroenterology, Nanfang Hospital, Southern Medical University, Guangzhou, China.
J Allergy Clin Immunol. 2021 Jan;147(1):267-279. doi: 10.1016/j.jaci.2020.09.003. Epub 2020 Sep 15.
Very-early-onset inflammatory bowel disease (VEOIBD) is a chronic inflammatory disease of the gastrointestinal tract occurring during infancy or early childhood. NOD-like receptor family, pyrin domain containing 3 (NLRP3) inflammasome has emerged as a crucial regulator of intestinal homeostasis; however, whether NLRP3 variants may modify VEOIBD risk is unknown.
We sought to investigate whether and how a rare NLRP3 variant, found in 3 patients with gastrointestinal symptoms, contributes to VEOIBD development.
Whole-exome sequencing and bioinformatic analysis were performed to screen disease-associated NLRP3 variants from a cohort of children with VEOIBD. Inflammasome activation was determined in reconstituted HEK293T human embryonic kidney cells with NLRP3 inflammasome components, doxycycline-inducible NLRP3 macrophages, as well as PBMCs and biopsies from patients with NLRP3 variants. Pathogenesis of the variants was determined using a dextran sulfate sodium-induced acute colitis model.
We identified a dominant gain-of-function missense variant of NLRP3, encoded by rs772009059 (R779C), in 3 patients with gastrointestinal symptoms. Functional analysis revealed that R779C increased NLRP3 inflammasome activation and pyroptosis in macrophages. This was mediated by enhanced deubiquitination of NLRP3 via binding with deubiquitinases BRCC3 and JOSD2, which are highly expressed in myeloid cells. In a dextran sulfate sodium-induced acute colitis model, NLRP3-R779C in hematopoietic cells resulted in more severe colitis, which can be ameliorated via knockdown of BRCC3 or JOSD2.
BRCC3 and JOSD2 mediate NLRP3-R779C deubiquitination, which promotes NLRP3 inflammasome activation and the risk of developing VEOIBD.
非常早发性炎症性肠病（VEOIBD）是一种发生在婴儿或幼儿期的胃肠道慢性炎症性疾病。NOD 样受体家族，富含吡喃结构域的蛋白 3（NLRP3）炎性小体已成为肠道内稳态的关键调节因子；然而，NLRP3 变体是否可以改变 VEOIBD 的风险尚不清楚。
我们旨在研究在有胃肠道症状的 3 名患者中发现的一种罕见 NLRP3 变体是否以及如何导致 VEOIBD 的发生。
对 VEOIBD 患儿队列进行全外显子组测序和生物信息学分析，筛选与疾病相关的 NLRP3 变体。用 NLRP3 炎性小体成分重建的 HEK293T 人胚肾细胞、诱导型 NLRP3 巨噬细胞以及来自 NLRP3 变体患者的 PBMC 和活检中测定炎性小体的激活。使用葡聚糖硫酸钠诱导的急性结肠炎模型确定变体的发病机制。
我们在 3 名有胃肠道症状的患者中发现了 NLRP3 的一种显性获得性功能错义变体，由 rs772009059（R779C）编码。功能分析显示，R779C 通过与髓系细胞中高表达的去泛素化酶 BRCC3 和 JOSD2 结合，增强 NLRP3 炎性小体的激活和巨噬细胞的细胞焦亡。在葡聚糖硫酸钠诱导的急性结肠炎模型中，造血细胞中的 NLRP3-R779C 导致更严重的结肠炎，通过敲低 BRCC3 或 JOSD2 可以改善。
BRCC3 和 JOSD2 介导 NLRP3-R779C 的去泛素化，从而促进 NLRP3 炎性小体的激活和 VEOIBD 的发病风险。
