Yang Ye, Wang Lin, Zeng Zhiyang, He Chunmeng, Wang Yanqiu, Huang Ying
Department of Gastroenterology, Children's Hospital of Fudan University/National Children's Medical Center, Shanghai, 201102, People's Republic of China.
Department of Central Laboratory, Fengxian Central Hospital Affiliated to Southern Medical University, Shanghai, 201499, People's Republic of China.
J Inflamm Res. 2024 Nov 12;17:8713-8726. doi: 10.2147/JIR.S488901. eCollection 2024.
Spleen tyrosine kinase (Syk) is a widely-expressed cytoplasmic non-receptor tyrosine kinase involved in regulating various signaling pathways and plays an important role in chronic inflammation and autoimmune diseases. Gain-of-function variants have been implicated in pediatric inflammatory bowel diseases. This study aimed to investigate the effects of gain-of-function variants on the susceptibility to experimental colitis and macrophage function.
Colitis was induced using dextran sodium sulfate and dinitrobenzene sulfonic acid in mice harboring a gain-of-function variant in (Syk). Intestinal inflammation was assessed via disease activity index, histological analysis, and Western blotting. The frequencies of macrophages, phagocytosis, and reactive oxygen species (ROS) production in bone marrow-derived macrophages (BMDM) were measured via flow cytometry. Chemokines and BMDM chemotaxis were analyzed using real-time quantitative reverse transcription polymerase chain reaction and Transwell assays. The expression of nucleotide-binding domain leucine-rich-containing family, pyrin domain-containing-3 (NLRP3) inflammasome-related proteins were detected using immunohistochemistry, enzyme-linked immunoassay and Western blotting.
Syk mice exhibited increased susceptibility to experimental colitis, and macrophage infiltration in colon tissues significantly increased. We observed increased expression of macrophage chemokines in colon tissues and enhanced chemotaxis in Syk BMDM. Additionally, we detected increased levels of fluorescent microspheres and 2.7-dichloride-hydro fluorescein diacetate-labeled ROS in Syk BMDM. Moreover, enhanced levels of NLRP3 inflammasome-related proteins were observed in the colon tissues and BMDM from Syk mice.
Gain-of-function variant in may contribute to the pathogenesis of pediatric inflammatory bowel diseases by promoting macrophage migration, phagocytosis, ROS production and activation of NLRP3 inflammasomes.
脾酪氨酸激酶（Syk）是一种广泛表达的细胞质非受体酪氨酸激酶，参与调节多种信号通路，在慢性炎症和自身免疫性疾病中起重要作用。功能获得性变异与儿童炎症性肠病有关。本研究旨在探讨功能获得性变异对实验性结肠炎易感性和巨噬细胞功能的影响。
在携带Syk功能获得性变异的小鼠中，使用葡聚糖硫酸钠和二硝基苯磺酸诱导结肠炎。通过疾病活动指数、组织学分析和蛋白质印迹法评估肠道炎症。通过流式细胞术测量骨髓来源巨噬细胞（BMDM）中巨噬细胞的频率、吞噬作用和活性氧（ROS）产生。使用实时定量逆转录聚合酶链反应和Transwell试验分析趋化因子和BMDM趋化性。使用免疫组织化学、酶联免疫吸附测定和蛋白质印迹法检测含核苷酸结合域富含亮氨酸家族、含pyrin结构域3（NLRP3）炎性小体相关蛋白的表达。
Syk小鼠对实验性结肠炎的易感性增加，结肠组织中的巨噬细胞浸润显著增加。我们观察到结肠组织中巨噬细胞趋化因子的表达增加，Syk BMDM中的趋化性增强。此外，我们在Syk BMDM中检测到荧光微球和2,7-二氯二氢荧光素二乙酸酯标记的ROS水平升高。此外，在Syk小鼠的结肠组织和BMDM中观察到NLRP3炎性小体相关蛋白水平升高。
Syk功能获得性变异可能通过促进巨噬细胞迁移、吞噬作用、ROS产生和NLRP3炎性小体的激活，导致儿童炎症性肠病的发病机制。
