title: Grouper (Epinephelus coioides) IL-34/MCSF2 and MCSFR1/MCSFR2 were involved in mononuclear phagocytes activation against Cryptocaryon irritans infection.
abstract: MCSF and its well-known receptor MCSFR had been well studied in humans, regulating the differentiation, proliferation, and survival of the mononuclear phagocyte system. IL-34, which is an alternative ligand of MCSF receptor, was recently identified as a novel cytokine and functionally overlaps with MCSF. However, the functional study of these receptors and their ligands in fish are largely unknown. In the present study, the cDNA of two potential grouper MCSFR ligands have been cloned, EcIL-34 (657 bp) and EcMCSF2 (804 bp), as well as an additional copy of grouper MCSFR, EcMCSFR2 (3141 bp). Sequence analysis showed that these three molecules had higher identities with other fish counterparts compared to mammals and their conserved structures and important functional residues were also analyzed. Tissue distribution analysis showed that EcIL-34 is dominant in brain, gill and spleen compared to EcMCSF2, which is dominant in head kidney, trunk kidney, skin, heart and muscle. EcMCSFR1 was dominant in the most tissues except head kidney and liver compared to EcMCSFR2. The different tissue distribution patterns of these two grouper MCSF receptors and their two ligands indicate the different mononuclear phagocyte differentiation and activation modes in different tissues. In Cryptocaryon irritans infected grouper, EcIL-34 and EcMCSFR2 were the most strongly up-regulated ligand and receptor in the infected sites, gill and skin. Their up-regulation confirmed the proliferation and activation of phagocytes in C. irritans infected sites, which would improve the antigen presentation and elicit the host local specific immune response. In C. irritans infected grouper head kidney, both ligands EcIL-34 and EcMCSF2 (especially EcMCSF2) were up-regulated, but both receptors EcMCSFR1 and EcMCSFR2 were down-regulated, which indicated that the phagocytes differentiation and proliferation may have occurred in this hemopoietic organ, and after that they migrated to the infected cites. The down-regulation of EcIL-34 and EcMCSF2 and no significant change of EcMCSFR1 and EcMCSFR2 in most time point of grouper spleen showed it was less involved in phagocytes response to C. irritans infection.
authors.affiliation: College of Animal Science, South China Agricultural University, Guangzhou 510642, Guangdong Province, PR China.
authors.forename: Ze-Quan
authors.initials: ZQ
authors.lastname: Mo
authors.affiliation: State Key Laboratory of Biocontrol/ Key Laboratory of Aquatic Product Safety (Sun Yat-Sen University), Ministry of Education, The School of Life Sciences, Sun Yat-sen University, Guangzhou 510275, Guangdong Province, PR China.
authors.forename: Yan-Wei
authors.initials: YW
authors.lastname: Li
authors.affiliation: College of Animal Science, South China Agricultural University, Guangzhou 510642, Guangdong Province, PR China.
authors.forename: Ling
authors.initials: L
authors.lastname: Zhou
authors.affiliation: State Key Laboratory of Biocontrol/ Key Laboratory of Aquatic Product Safety (Sun Yat-Sen University), Ministry of Education, The School of Life Sciences, Sun Yat-sen University, Guangzhou 510275, Guangdong Province, PR China.
authors.forename: An-Xing
authors.initials: AX
authors.lastname: Li
authors.affiliation: School of Bioscience and Biotechnology, South China University of Technology, Guangzhou 510006, PR China. Electronic address: xcluo@scut.edu.cn.
authors.forename: Xiao-Chun
authors.initials: XC
authors.lastname: Luo
authors.affiliation: College of Animal Science, South China Agricultural University, Guangzhou 510642, Guangdong Province, PR China. Electronic address: dxm72@scau.edu.cn.
authors.forename: Xue-Ming
authors.initials: XM
authors.lastname: Dan
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001492:Bass / Q000235:genetics* / Q000276:immunology / Q000378:metabolism; D016798:Ciliophora / Q000502:physiology; D016770:Ciliophora Infections / Q000235:genetics / Q000276:immunology / Q000469:parasitology / Q000662:veterinary*; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000235:genetics / Q000378:metabolism; D005393:Fish Diseases / Q000235:genetics* / Q000276:immunology* / Q000469:parasitology; D029941:Fish Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D005786:Gene Expression Regulation; D007378:Interleukins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D016173:Macrophage Colony-Stimulating Factor / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D009928:Organ Specificity; D010586:Phagocytes; D010802:Phylogeny; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D016186:Receptor, Macrophage Colony-Stimulating Factor / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D016415:Sequence Alignment / Q000662:veterinary
chemical_list: D018076:DNA, Complementary; D029941:Fish Proteins; D007378:Interleukins; D012333:RNA, Messenger; D016173:Macrophage Colony-Stimulating Factor; D016186:Receptor, Macrophage Colony-Stimulating Factor
keywords: Cryptocaryon irritans; Epinephelus coioides; IL-34; MCSF; MCSFR