Identification and characterization of three CXC chemokines in Asian swamp eel (Monopterus albus) uncovers a third CXCL11_like group in fish

• Published in: Developmental and comparative immunology 2019-12, Vol.101, p.103454-103454, Article 103454
• Main Authors: Yuan, Hanwen, Li, Youshen, Panpan Han, Tian, Guangming, Zhang, Wenbing, Guo, Huizhi, Xu, Qiaoqing, Wang, Tiehui
• Format: Article
• Language: English
• Subjects: Adaptive immunity; Amino Acid Sequence; Amino acids; Animals; Antiviral agents; Asian swamp eel (Monopterus albus); Bacterial diseases; Biological evolution; Cell adhesion & migration; Cell migration; Chemokine CXCL11 - genetics; Chemokine CXCL11 - immunology; Chemokines; CXC chemokines; CXCL11 protein; CXCL11_L3; CXCL12 protein; CXCL_F2; Eels; Evolution; Fish; Fish Proteins - genetics; Fish Proteins - immunology; Freshwater fish; Helper cells; Immune response; Immune system; Inflammation; Lymphocytes T; Mammals; Modulation; Monopterus albus; Organs; Phylogeny; Polyinosinic:polycytidylic acid; Sequence Alignment; Smegmamorpha - genetics; Smegmamorpha - immunology; Species
• ISSN: 0145-305X; 1879-0089
• DOI: 10.1016/j.dci.2019.103454

Chemokines direct cell migration in development and immune defense, and bridge between innate and adaptive immune responses. The chemokine gene family has been rapidly evolving and has undergone species/lineage-specific expansion. Mammals possess inflammatory CXC chemokines CXCL1-8/15 and CXCL9-11 sub-groups, and homeostatic CXCL12-14, 16–17. Orthologues of mammalian CXCL12-14, three chemokines related to CXCL1-8/15 (CXCL8_L1-3), two chemokines related to CXC9-11 (CXCL11_L1-2), and five fish-specific chemokines (CXCL_F1-5) have been described in teleosts. In this study, we reported three novel CXC chemokines in Asian swamp eel Monopterus albus, a commercially important freshwater fish species in China. Two of them belong to the fish-specific CXCL_F2 group, named CXCL_F2a/b, that share 89.5% amino acid identity. The other (CXCL11_L3) belongs to a third CXCL11_L related to the mammalian CXCL9-11 subfamily found only in percomorph fish species, and is the only CXCL9-11 related molecules in this lineage. Mammalian CXCL9-11 attract Th1 cells, and block the migration of Th2 cells in an immune response. This study suggests that all major lineages of teleosts have a CXCL9-11 related chemokine that will aid future functional investigation of CXCL11_L in fish. Cxcl_f2a is highly expressed constitutively in the skin of swamp eels that may attract immune cells to protect the skin in the absence of scales. Cxcl11_l3 and cxcl_f2b are highly expressed in immune tissues/organs and are up-regulated by the viral mimic poly I:C, but not bacterial infection in vivo, suggesting their role in anti-viral defense. The two cxcl_f2 paralogues are differentially expressed and modulated, indicating sub- and/or neo-functionalization. •CXCL11_L3 represents a third CXCL9-11 related chemokine in percomorph fish species.•Cxcl_f2a and cxcl_f2b are differentially expressed and modulated in vivo.•Cxcl11_l3 and cxcl_f2b are induced by poly I:C suggesting a role in anti-viral defence.