School of Marine Sciences, Ningbo University, Ningbo, Zhejiang, 315211, China.
School of Marine Sciences, Ningbo University, Ningbo, Zhejiang, 315211, China; Key Laboratory of Aquacultural Biotechnology, Ministry of Education, Ningbo University, Ningbo, Zhejiang, 315211, China; Collaborative Innovation Center for Zhejiang Marine High-efficiency and Healthy Aquaculture, Ningbo University, Ningbo, Zhejiang, 315211, China.
Fish Shellfish Immunol. 2023 Dec;143:109209. doi: 10.1016/j.fsi.2023.109209. Epub 2023 Nov 7.
Galectins, as members of lectin families, exhibit a high affinity for β-galactosides and play diverse roles in biological processes. They function as pattern recognition receptors (PRRs) with important roles in immune defense. In this study, galectin-1, designated as SpGal-1, was identified and characterized from silver pomfret (Pampus argenteus). The SpGal-1 comprises an open reading frame (ORF) spanning 396 base pairs (bp) and encodes a deduced amino acid (aa) sequence containing a single carbohydrate recognition domain (CRD). Sublocalization analysis revealed that SpGal-1 was mainly expressed in the cytoplasm. The mRNA transcripts of SpGal-1 were ubiquitously detected in various tissues, with a higher expression level in the intestine. In addition, when exposed to Photobacterium damselae subsp. damselae (PDD) infection, both the liver and head kidney exhibited significantly increased SpGal-1 mRNA expression. The recombinant protein of SpGal-1 (named as rSpGal-1) demonstrated hemagglutination against red blood cells (RBCs) from Larimichthys crocea and P. argenteus in a Ca or β-Mercaptoethanol (β-ME)-independent manner. Notably, rSpGal-1 could bind with various pathogen-associated molecular patterns (PAMPs) including D-galactose, D-mannose, lipopolysaccharide (LPS), and peptidoglycan (PGN), with highest affinity to PGN. Moreover, rSpGal-1 effectively interacted with an array of bacterial types encompassing Gram-positive bacteria (Staphylococcus aureus and Nocardia seriolae) and Gram-negative bacteria (PDD and Escherichia coli, among others), with the most robust binding affinity towards PDD. Collectively, these findings highlight that SpGal-1 is a crucial PRR with involvement in the host immune defense of silver pomfret.
半乳糖凝集素作为凝集素家族的成员，对β-半乳糖苷具有高亲和力，在生物过程中发挥多种作用。它们作为模式识别受体（PRRs）发挥作用，在免疫防御中具有重要作用。在本研究中，从银鲳（Pampus argenteus）中鉴定并表征了半乳糖凝集素-1，命名为 SpGal-1。SpGal-1 包含一个 396 个碱基对（bp）的开放阅读框（ORF），编码一个含有单个糖识别结构域（CRD）的推定氨基酸（aa）序列。亚细胞定位分析表明，SpGal-1 主要表达在细胞质中。SpGal-1 的 mRNA 转录本在各种组织中广泛检测到，在肠中表达水平较高。此外，当暴露于美人鱼发光杆菌亚种美人鱼发光杆菌（PDD）感染时，肝脏和头肾的 SpGal-1 mRNA 表达均显著增加。SpGal-1 的重组蛋白（命名为 rSpGal-1）以 Ca 或β-巯基乙醇（β-ME）独立的方式对来自大黄鱼和银鲳的红细胞（RBC）具有血凝作用。值得注意的是，rSpGal-1 可以与各种病原体相关分子模式（PAMPs）结合，包括 D-半乳糖、D-甘露糖、脂多糖（LPS）和肽聚糖（PGN），与 PGN 的亲和力最高。此外，rSpGal-1 还可以与多种细菌类型有效相互作用，包括革兰氏阳性菌（金黄色葡萄球菌和诺卡氏菌）和革兰氏阴性菌（PDD 和大肠杆菌等），与 PDD 的结合亲和力最强。综上所述，这些发现表明 SpGal-1 是一种重要的 PRR，参与了银鲳的宿主免疫防御。
