Zhang Yunru, Zhang Xiaolong, Chen Xi, Wang Yujie, Ayana Gelana Urgesa, Shen Ruling, Lin Jinxing, Qiu Junqiang, Zhang Qinghua
Key Laboratory of Exploration and Utilization of Aquatic Genetic Resources, Ministry of Education, Shanghai Ocean University, Shanghai, 201306, China; International Research Center for Marine Biosciences, Ministry of Science and Technology, Shanghai Ocean University, Shanghai, 201306, China.
Key Laboratory of Exploration and Utilization of Aquatic Genetic Resources, Ministry of Education, Shanghai Ocean University, Shanghai, 201306, China; International Research Center for Marine Biosciences, Ministry of Science and Technology, Shanghai Ocean University, Shanghai, 201306, China; Shanghai Laboratory Animal Research Center, Jinke Rd.3577, Shanghai, 201203, China.
Fish Shellfish Immunol. 2025 Nov;166:110676. doi: 10.1016/j.fsi.2025.110676. Epub 2025 Aug 22.
Activation of the NOD-like receptor thermal protein domain-associated protein 3 (NLRP3) inflammasome is critical in the innate immune response. However, the role of lysine acetyltransferase 7 (Kat7) in NLRP3 inflammasome activation in teleost fish remains unreported. In this study, we firstly cloned the kat7b gene from zebrafish (Danio rerio) and investigated its role in NLRP3 inflammasome activation and disease resistance. Bioinformatic analysis revealed that DrKat7b (D. rerio Kat7b) is a homolog of human and murine Kat7. In healthy zebrafish, we observed a widespread expression of Drkat7b in the tissues examined. Its expression significantly increased in multiple tissues following Aeromonas hydrophila infection. In lipopolysaccharide (LPS)-stimulated zebrafish fibroblasts (ZF4) cells, overexpression of Drkat7b up-regulated the mRNA levels of key genes involved in NLRP3 activation and promoted interleukin-1β (IL-1β) protein release. Dual-luciferase reporter assays utilizing the zebrafish NIMA-related kinase 7 (Nek7) promoter demonstrated that Drkat7b enhances Drnek7 (D. rerio nek7) transcription. Western blot analysis further confirmed that DrKat7b up-regulated DrNek7 expression at protein level. Immunofluorescence (IF) studies revealed DrKat7b localizes in the nucleus and colocalization with DrNek7. Co-immunoprecipitation experiments further confirmed a direct protein-protein interaction between DrKat7b and DrNek7. Additionally, RT-qPCR and ELISA analysis suggested that β-sitosterol may act as an inhibitor of the Drkat7b-NLRP3 inflammatory signaling pathway induced by CuSO or LPS. This study firstly identifies a Kat7b-Nek7-NLRP3 regulatory axis, reveals β-sitosterol as a potential inhibitor of Drkat7b, and provides both experimental evidences and theoretical insights into the regulation of NLRP3 in teleosts.
核苷酸结合寡聚化结构域样受体热蛋白结构域相关蛋白3（NLRP3）炎性小体的激活在先天免疫反应中至关重要。然而，赖氨酸乙酰转移酶7（Kat7）在硬骨鱼NLRP3炎性小体激活中的作用尚未见报道。在本研究中，我们首先从斑马鱼（Danio rerio）中克隆了kat7b基因，并研究了其在NLRP3炎性小体激活和抗病性中的作用。生物信息学分析表明，DrKat7b（斑马鱼Kat7b）是人和小鼠Kat7的同源物。在健康斑马鱼中，我们观察到Drkat7b在所检测的组织中广泛表达。嗜水气单胞菌感染后，其在多个组织中的表达显著增加。在脂多糖（LPS）刺激的斑马鱼成纤维细胞（ZF4）中，Drkat7b的过表达上调了参与NLRP3激活的关键基因的mRNA水平，并促进白细胞介素-1β（IL-1β）蛋白释放。利用斑马鱼NIMA相关激酶7（Nek7）启动子的双荧光素酶报告基因检测表明，Drkat7b增强了Drnek7（斑马鱼nek7）的转录。蛋白质免疫印迹分析进一步证实，DrKat7b在蛋白质水平上上调了DrNek7的表达。免疫荧光（IF）研究表明，DrKat7b定位于细胞核，并与DrNek7共定位。免疫共沉淀实验进一步证实了DrKat7b与DrNek7之间存在直接的蛋白质-蛋白质相互作用。此外，RT-qPCR和ELISA分析表明，β-谷甾醇可能是CuSO或LPS诱导的Drkat7b-NLRP3炎症信号通路的抑制剂。本研究首次鉴定了Kat7b-Nek7-NLRP3调控轴，揭示了β-谷甾醇作为Drkat7b的潜在抑制剂，并为硬骨鱼中NLRP3的调控提供了实验证据和理论见解。
