title: A novel siglec (CgSiglec-1) from the Pacific oyster (Crassostrea gigas) with broad recognition spectrum and inhibitory activity to apoptosis, phagocytosis and cytokine release.
abstract: Sialic acid binding immunoglobulin-type lectin (siglec) belongs to the immunoglobulin superfamily (IgSF), which acts as regulator involved in glycan recognition and signal transduction in the immune and nervous systems. In the present study, a siglec gene (designated CgSiglec-1) was characterized from the Pacific oyster, Crassostrea gigas. The cDNA of CgSiglec-1 was of 1251 bp encoding a predicted polypeptide of 416 amino acids. CgSiglec-1 was composed of two I-set immunoglobulin (Ig) domains, one transmembrane (TM) domain and two ITIM motifs, sharing a sequence similarity with vertebrate CD22 homologs. The mRNA expression of CgSiglec-1 could be detected in all the selected tissues, with the highest level in hemocytes and labial palps. The confocal analysis revealed that CgSiglec-1 mainly distributed on the cytoplasmic membrane of the oyster hemocytes. In addition, the mRNA transcripts of CgSiglec-1 in hemocytes increased significantly (4.29-fold to that of control group, p < 0.05) after Vibrio splendidus stimulation. The recombinant CgSiglec-1 protein (rCgSiglec-1) could bind to poly sialic acid (pSIAS), lipopolysaccharides (LPS) and peptidoglycan (PGN) in a dose-dependent manner. The blockade of CgSiglec-1 by specific polyclonal antibodies could enhance the LPS-induced cell apoptosis, phagocytosis towards V. splendidus and the release of cytokines, such as CgTNF-1, CgIFNLP and CgIL-17. The results collectively indicated that CgSiglec-1 could act as a bridge molecule between invader recognition and signal transduction cascade, and modulate the immune response by inhibiting various important processes of immunity in oyster.
authors.affiliation: Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China; University of Chinese Academy of Sciences, Beijing 100049, China.
authors.forename: Conghui
authors.initials: C
authors.lastname: Liu
authors.affiliation: Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China.
authors.forename: Shuai
authors.initials: S
authors.lastname: Jiang
authors.affiliation: Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China.
authors.forename: Mengqiang
authors.initials: M
authors.lastname: Wang
authors.affiliation: Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China.
authors.forename: Lingling
authors.initials: L
authors.lastname: Wang
authors.affiliation: Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China; University of Chinese Academy of Sciences, Beijing 100049, China.
authors.forename: Hao
authors.initials: H
authors.lastname: Chen
authors.affiliation: Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China; University of Chinese Academy of Sciences, Beijing 100049, China.
authors.forename: Jiachao
authors.initials: J
authors.lastname: Xu
authors.affiliation: Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China; University of Chinese Academy of Sciences, Beijing 100049, China.
authors.forename: Zhao
authors.initials: Z
authors.lastname: Lv
authors.affiliation: Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China; Key Laboratory of Mariculture & Stock Enhancement in North China's Sea, Ministry of Agriculture, Dalian Ocean University, Dalian 116023, China. Electronic address: lshsong@dlou.edu.cn.
authors.forename: Linsheng
authors.initials: L
authors.lastname: Song
mesh_terms: D000818:Animals; D017209:Apoptosis; D003001:Cloning, Molecular; D016207:Cytokines / Q000378:metabolism; D006434:Hemocytes / Q000382:microbiology / Q000502:physiology*; D007113:Immunity, Innate; D019158:N-Acetylneuraminic Acid / Q000378:metabolism; D010125:Ostreidae / Q000276:immunology*; D010587:Phagocytosis; D051192:Receptors, Pattern Recognition / Q000235:genetics / Q000378:metabolism*; D063267:Sialic Acid Binding Ig-like Lectin 1 / Q000235:genetics / Q000378:metabolism*; D015398:Signal Transduction; D059467:Transcriptome; D015854:Up-Regulation; D014735:Vibrio Infections / Q000276:immunology*
chemical_list: D016207:Cytokines; D051192:Receptors, Pattern Recognition; D063267:Sialic Acid Binding Ig-like Lectin 1; D019158:N-Acetylneuraminic Acid
keywords: Cascading inhibitory; Innate immune response; Phagocytosis; Recognition spectrum; Sialic acid binding immunoglobulin-type lectins