title: An integrin from oyster Crassostrea gigas mediates the phagocytosis toward Vibrio splendidus through LPS binding activity.
abstract: Integrins are a family of cell adhesion molecules which play important roles in the regulation of cell adhesion, migration, proliferation, apoptosis and phagocytosis. In the present study, the immune function of an integrin from the oyster Crassostrea gigas (designated CgIntegrin) was characterized to understand the regulatory mechanism of hemocyte phagocytosis toward different microbes. The full-length cDNA of CgIntegrin was 2571 bp with an open reading frame (ORF) of 2397 bp, encoding a polypeptide of 799 amino acids. The mRNA transcripts of CgIntegrin were predominantly detected in hemocytes, gonad and adductor muscle, while lowly in hepatopancreas, mantle and gill. The mRNA expression level was up-regulated at 6 h post lipopolysaccharide (LPS) stimulation (p < 0.01), while no significant change was observed after peptidoglycan (PGN) stimulation. The oyster hemocytes with relative high CgIntegrin expression level exhibited different phagocytic abilities towards different microorganism and particles, such as Gram-positive bacteria Vibrio splendidus, Gram-negative bacteria Staphylococcus aureus and latex beads. Moreover, the phagocytic rate towards V. splendidus was significantly decreased after the blockade of CgIntegrin using the polyclonal antibody. The recombinant CgIntegrin (rCgIntegrin) displayed agglutinating activity towards V. splendidus but not S. aureus and Y. lipolytica. It also exhibited a higher binding affinity towards LPS (compared to rTrx group) in a dose-dependent manner with the apparent dissociation constant (Kd) of 5.53 × 10(-6) M. The results indicated that CgIntegrin served as a pattern recognition receptor with LPS binding activity, which could directly bind to V. splendidus and enhance the phagocytosis of oyster hemocytes.
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: Zhihao
authors.initials: Z
authors.lastname: Jia
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: Tao
authors.initials: T
authors.lastname: Zhang
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: Dalian Polytechnic University, Dalian 116034, China.
authors.forename: Qi
authors.initials: Q
authors.lastname: Cheng
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: Mingzhe
authors.initials: M
authors.lastname: Sun
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 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: D000371:Agglutination / Q000276:immunology; D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D049896:Crassostrea / Q000235:genetics / Q000276:immunology*; D018076:DNA, Complementary / Q000235:genetics; D006434:Hemocytes / Q000276:immunology; D016023:Integrins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000276:immunology*; D008070:Lipopolysaccharides / Q000276:immunology; D008863:Microspheres; D008969:Molecular Sequence Data; D010587:Phagocytosis / Q000276:immunology*; D012333:RNA, Messenger / Q000235:genetics; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA; D015398:Signal Transduction / Q000276:immunology; D013211:Staphylococcus aureus / Q000276:immunology*; D014733:Vibrio / Q000276:immunology*
chemical_list: D018076:DNA, Complementary; D016023:Integrins; D008070:Lipopolysaccharides; D012333:RNA, Messenger
keywords: Crassostrea gigas; Innate immunity; Integrin; Liposaccharides; Phagocytosis; Vibrio splendidus