School of Animal Science, Yangtze University, Jingzhou, 434020, China; Guangdong Provincial Key Laboratory of Marine Biotechnology, Shantou University, Shantou, 515063, PR China.
School of Animal Science, Yangtze University, Jingzhou, 434020, China.
Dev Comp Immunol. 2019 Dec;101:103454. doi: 10.1016/j.dci.2019.103454. Epub 2019 Jul 19.
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.
趋化因子指导细胞在发育和免疫防御中的迁移，并在先天免疫和适应性免疫反应之间架起桥梁。趋化因子基因家族一直在快速进化，并经历了物种/谱系特异性扩张。哺乳动物具有炎症性 CXC 趋化因子 CXCL1-8/15 和 CXCL9-11 亚群，以及稳态 CXCL12-14、16-17。在硬骨鱼中，已经描述了哺乳动物 CXCL12-14 的同源物、与 CXCL1-8/15 相关的三种趋化因子（CXCL8_L1-3）、与 CXC9-11 相关的两种趋化因子（CXCL11_L1-2）和五种鱼类特异性趋化因子（CXCL_F1-5）。在这项研究中，我们报道了亚洲沼鳗 Monopterus albus 中的三种新型 CXC 趋化因子，亚洲沼鳗是中国一种商业上重要的淡水鱼类。其中两种属于鱼类特异性 CXCL_F2 组，命名为 CXCL_F2a/b，它们具有 89.5%的氨基酸同一性。另一种（CXCL11_L3）属于仅在鲈形目鱼类中发现的与哺乳动物 CXCL9-11 亚家族相关的第三种 CXCL11_L，是该谱系中唯一的 CXCL9-11 相关分子。哺乳动物 CXCL9-11 吸引 Th1 细胞，并在免疫反应中阻止 Th2 细胞的迁移。本研究表明，硬骨鱼的所有主要谱系都有一种与 CXCL9-11 相关的趋化因子，这将有助于未来对鱼类 CXCL11_L 的功能研究。Cxcl_f2a 在沼泽鳗的皮肤中持续高表达，可能会吸引免疫细胞在没有鳞片的情况下保护皮肤。Cxcl11_l3 和 cxcl_f2b 在免疫组织/器官中高表达，并被病毒模拟物 poly I:C 上调，但在体内不受细菌感染的影响，表明它们在抗病毒防御中发挥作用。这两个 cxcl_f2 旁系同源物的表达和调节存在差异，表明亚功能化和/或新功能化。
