Abstract
In mammals, Interleukin-17 cytokine family plays critical roles in both acute and chronic inflammatory responses. In fish species, three Interleukin-17A/F (IL-17A/F) genes have been identified to be homologous to mammalian IL-17A and IL-17F, but little is known about their functional activity. In this study, Pf_IL-17A/F1, 2 and 3 genes were cloned from yellow catfish (Pelteobagrus fulvidraco) and they differed in protein structure and exon length, implying that they may have divergent bioactivity. Real-time quantitative PCR analyses revealed that three Pf_IL-17A/F genes were highly expressed in blood and mucosal tissues (skin+mucus and gill) from healthy adult fish. The mRNA expressions of Pf_IL-17A/F1, 2 and 3 genes were significantly up-regulated in the gill, skin+mucus, head kidney and spleen after challenge with Edwardsiella ictaluri and in the isolated peripheral blood leucocytes (PBLs) of yellow catfish after stimulation with phytohaemagglutinin (PHA), lipopolysaccharides (LPS), peptidoglycan (PGN) and polyinosinic-polycytidylic acid (Poly I:C). These results indicate that Pf_IL-17A/F1, 2 and 3 genes may play a vital role in the regulation of immune against pathogens. Additionally, the recombinant (r) Pf_IL-17A/F1, 2 and 3 proteins significantly induced the mRNA expressions of proinflammatory cytokines, chemokines and antibacterial peptides genes, and the rPf_IL-17A/F 2 and 3 proteins promoted phagocytosis of PBLs more powerfully than the rPf_IL-17A/F1. Furthermore, the rPf_IL-17A/F1, 2 and 3 proteins might activate the NF-κB and MAPK signal pathways by IL-17RA, ACT1, TRAF6, TRAF2, TRAF5 and TAK1, indicating that the three Pf_IL-17A/F proteins may play different roles in promoting inflammatory response.
Highlights
Water quality is one of the most critical factors of healthy aquaculture
The partial cDNA sequences of the Pf_IL-17A/F1, Pf_IL-17A/F2 and Pf_IL-17A/F3 genes were cloned from yellow catfish
The Pf_IL-17A/F1 cDNA consisted of an open reading frame (ORF) of 483 bp and a 3’untranslated region (UTR) of 236 bp
Summary
Water quality is one of the most critical factors of healthy aquaculture. The deterioration of the water environment can reduce fish growth rate and lower fish immunity, which may lead to the invasion of pathogens and the occurrence of fish diseases. Inflammation is broadly defined as a protective response of the organism to stimulation by invading pathogens or endogenous signals such as damaged cells [1]. Moderate inflammation can accelerate the clearance of pathogens and tissue repair. As the medium of communication between cells, plays an important regulative role in the development of inflammation [2]. As an important cytokine family, the interleukin-17 family can promote inflammation by activating downstream pathways to induce the expression of antimicrobial peptides, inflammatory cytokines, and chemokines [3]
Sign-in/Register to view highlights & summary 
Published Version (
Free)
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call