title: CgIL17-5, an ancient inflammatory cytokine in Crassostrea gigas exhibiting the heterogeneity functions compared with vertebrate interleukin17 molecules.
abstract: Interleukin 17 (IL17) is a proinflammatory cytokine that plays an important role in immune response. Recently, five novel IL17 homologs have been identified by screening and analyzing the genome of pacific oyster Crassostrea gigas. In the present study, the functions of CgIL17-5 were investigated by examining the distribution of its mRNA and protein, ligands binding and modulation in immune response. The mRNA expression levels of CgIL17-5 in hemocytes of oysters post twice challenges of Vibrio splendidus were all significantly up-regulated (P < 0.01), while the secondary pathogen infection attenuated the expression level of CgIL17-5 mRNA compared with the primary challenge. CgIL17-5 was found to be located on oyster hemocyte membranes through fluorescence confocal assay. The luciferase reporter assays showed that CgIL17-5 could activate the transfactors NF-κB, CREB and ATF-1, and involve in their signal pathways in HEK293T cells. Meanwhile, CgIL17-5 could augment the IL6 synthesis in HuVEC cells, playing the similar roles as human IL17 in inflammatory response. Additionally, the recombinant CgIL17-5 (rCgIL17-5) could directly bind peptidoglycan (PGN), lipopolysaccharide (LPS), poly (I:C) and β-1,3-glucan, with the highest affinity to PGN, and significantly inhibit the growth of Micrococcus luteus and Escherichia coli. All the results collectively suggested that CgIL17-5, as an ancient inflammatory cytokine, could not only activate signal transduction for the release of other cytokines, but also mediate the clearance of extracellular bacteria in oysters.
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: Lusheng
authors.initials: L
authors.lastname: Xin
authors.affiliation: Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China.
authors.forename: Huan
authors.initials: H
authors.lastname: Zhang
authors.affiliation: Ningbo University, Ningbo 315211, China.
authors.forename: Ran
authors.initials: R
authors.lastname: Zhang
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: Hui
authors.initials: H
authors.lastname: Li
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: Weilin
authors.initials: W
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.
authors.forename: Hao
authors.initials: H
authors.lastname: Wang
authors.affiliation: Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China.
authors.forename: Limei
authors.initials: L
authors.lastname: Qiu
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@qdio.ac.cn.
authors.forename: Linsheng
authors.initials: L
authors.lastname: Song
mesh_terms: D000818:Animals; D058491:Bacterial Load; D049896:Crassostrea; D017362:Cyclic AMP Response Element-Binding Protein / Q000378:metabolism; D005786:Gene Expression Regulation; D057809:HEK293 Cells; D006434:Hemocytes / Q000276:immunology* / Q000382:microbiology; D006801:Humans; D007109:Immunity; D056747:Immunomodulation; D018836:Inflammation Mediators / Q000378:metabolism; D020381:Interleukin-17 / Q000235:genetics / Q000378:metabolism*; D016328:NF-kappa B / Q000378:metabolism; D011485:Protein Binding; D015533:Transcriptional Activation; D014714:Vertebrates; D014733:Vibrio / Q000254:growth & development / Q000276:immunology*; D014735:Vibrio Infections / Q000235:genetics / Q000276:immunology*
chemical_list: D017362:Cyclic AMP Response Element-Binding Protein; D018836:Inflammation Mediators; D020381:Interleukin-17; D016328:NF-kappa B
keywords: Bacteriostasis; Crassostrea gigas; Inflammation; Interleukin 17; Pathogen-associated molecular pattern recognition