Yang Qian, Sun Jiejie, Wu Wei, Xing Zhen, Yan Xiaoxue, Lv Xiaoqian, Wang Lingling, Song Linsheng
Liaoning Key Laboratory of Marine Animal Immunology & Disease Control, Dalian Ocean University, Dalian, 116023, China; Laboratory of Marine Fisheries Science and Food Production Processes, Qingdao National Laboratory for Marine Science and Technology, Qingdao, 266235, China; Liaoning Key Laboratory of Marine Animal Immunology, Dalian Ocean University, Dalian, 116023, China.
Liaoning Key Laboratory of Marine Animal Immunology & Disease Control, Dalian Ocean University, Dalian, 116023, China; Southern Laboratory of Ocean Science and Engineering (Guangdong, Zhuhai), Zhuhai, 519000, China; Laboratory of Marine Fisheries Science and Food Production Processes, Qingdao National Laboratory for Marine Science and Technology, Qingdao, 266235, China; Liaoning Key Laboratory of Marine Animal Immunology, Dalian Ocean University, Dalian, 116023, China; Dalian Key Laboratory of Prevention and Control of Aquatic Animal Diseases, Dalian Ocean University, Dalian, 116023, China.
Dev Comp Immunol. 2023 Dec;149:105063. doi: 10.1016/j.dci.2023.105063. Epub 2023 Sep 18.
Galectin-9 is a tandem-repeat type member of galectin family participating in various immune responses, such as cell agglutination, phagocytosis, and autophagy. In the present study, a tandem repeat galectin-9 (defined as CgGal-9) was identified from Pacific oyster Crassostrea gigas, which consisted of two conserved carbohydrate recognition domains (CRDs) joined by a linker peptide. CgGal-9 was closely clustered with CaGal-9 from C. angulata, and they were assigned into the branch of invertebrate galectin-9s in the phylogenetic tree. The mRNA transcripts of CgGal-9 were detected in all the tested tissues, with the highest expression level in haemocytes. The mRNA expressions of CgGal-9 in haemocytes increased significantly after lipopolysaccharide (LPS) and Vibrio splendidus stimulation. The recombinant CgGal-9 was able to bind all the examined pathogen-associated molecular patterns (LPS, peptidoglycan, and mannose) and microbes (V. splendidus, Escherichia coli, Micrococcus luteus, Staphylococcus aureus, Bacillus subtilis, and Pichia pastoris), and agglutinated most of them in the presence of Ca. In CgGal-9-RNAi oysters, the mRNA expressions of autophagy related genes (CgBeclin1, CgATG5, CgP62 and CgLC3) in haemocytes decreased significantly while that of CgmTOR increased significantly at 3 h after V. splendidus stimulation. The autophagy level and mRNA expressions of autophagy related genes decreased in haemocytes after CgGal-9 was blocked by the corresponding antibody. These results revealed that CgGal-9 was able to bind different microbes and might be involved in haemocyte autophagy in the immune response of oyster.
半乳糖凝集素-9是半乳糖凝集素家族的串联重复型成员，参与多种免疫反应，如细胞凝集、吞噬作用和自噬。在本研究中，从太平洋牡蛎（Crassostrea gigas）中鉴定出一种串联重复半乳糖凝集素-9（定义为CgGal-9），它由两个保守的碳水化合物识别结构域（CRD）通过一个连接肽连接而成。CgGal-9与角贝（C. angulata）的CaGal-9紧密聚类，在系统发育树中它们被归入无脊椎动物半乳糖凝集素-9分支。在所有检测的组织中均检测到CgGal-9的mRNA转录本，血细胞中的表达水平最高。脂多糖（LPS）和灿烂弧菌（Vibrio splendidus）刺激后，血细胞中CgGal-9的mRNA表达显著增加。重组CgGal-9能够结合所有检测的病原体相关分子模式（LPS、肽聚糖和甘露糖）以及微生物（灿烂弧菌、大肠杆菌、藤黄微球菌、金黄色葡萄球菌、枯草芽孢杆菌和毕赤酵母），并且在有Ca存在的情况下能凝集其中大部分。在CgGal-9-RNAi牡蛎中，灿烂弧菌刺激3小时后，血细胞中自噬相关基因（CgBeclin1、CgATG5、CgP62和CgLC3）的mRNA表达显著下降，而CgmTOR的表达显著增加。用相应抗体阻断CgGal-9后，血细胞中的自噬水平和自噬相关基因的mRNA表达下降。这些结果表明，CgGal-9能够结合不同的微生物，可能参与牡蛎免疫反应中的血细胞自噬。
