Molecular characterization of the liver-expressed antimicrobial peptide 2 (LEAP-2) in a teleost fish, Plecoglossus altivelis: antimicrobial activity and molecular mechanism.
Liver-expressed antimicrobial peptide 2 (LEAP-2) is widespread in fish and plays an important role in the host's innate immune system. In this study, full-length cDNA for LEAP-2 (PaLEAP-2) gene was cloned and sequenced from ayu, Plecoglossus altivelis. PaLEAP-2 mRNA was detected in a wide range of tissues, with the highest level of transcripts found in the liver. Upon induction by Vibrio anguillarum, its expression significantly increased in the liver, kidney, spleen, gill, and heart, but decreased in the intestine. The PaLEAP-2 mature peptide was chemically synthesized; it exhibited selective antimicrobial activity against various bacteria in vitro. PaLEAP-2 at high concentration reduced the bacterial load and improved the survival rate of V. anguillarum-infected ayu. Moreover, it inhibited the expression of mRNAs for TNF-α and IL-1β in V. anguillarum-infected ayu, both at high and low concentrations. PaLEAP-2 induced hydrolysis of the pET-22b plasmid DNA and bacterium genomic DNA. These results suggest that PaLEAP-2 plays a role in ayu immune responses against bacterial infection.
Laboratory of Biochemistry and Molecular Biology, School of Marine Sciences, Ningbo University, Ningbo 315211, China; The Donghai Sea Collaborative Innovation Center for Industrial Upgrading Mariculture, Ningbo University, Ningbo 315211, China.
He-Xiang
HX
Li
Laboratory of Biochemistry and Molecular Biology, School of Marine Sciences, Ningbo University, Ningbo 315211, China.
Xin-Jiang
XJ
Lu
Laboratory of Biochemistry and Molecular Biology, School of Marine Sciences, Ningbo University, Ningbo 315211, China.
Chang-Hong
CH
Li
Laboratory of Biochemistry and Molecular Biology, School of Marine Sciences, Ningbo University, Ningbo 315211, China; The Donghai Sea Collaborative Innovation Center for Industrial Upgrading Mariculture, Ningbo University, Ningbo 315211, China. Electronic address: jchen1975@163.com.
Jiong
J
Chen
D000818:Animals; D023181:Antimicrobial Cationic Peptides / Q000276:immunology*; D005393:Fish Diseases / Q000276:immunology; D029941:Fish Proteins / Q000276:immunology*; D005399:Fishes / Q000276:immunology*; D005786:Gene Expression Regulation / Q000276:immunology*; D053583:Interleukin-1beta / Q000276:immunology; D008099:Liver / Q000276:immunology*; D009928:Organ Specificity / Q000276:immunology; D012333:RNA, Messenger / Q000378:metabolism; D014409:Tumor Necrosis Factor-alpha / Q000276:immunology; D014733:Vibrio / Q000276:immunology; D014735:Vibrio Infections / Q000276:immunology / Q000662:veterinary
D023181:Antimicrobial Cationic Peptides; D029941:Fish Proteins; D053583:Interleukin-1beta; D012333:RNA, Messenger; D014409:Tumor Necrosis Factor-alpha
Antimicrobial activity; Bacterial load; Gene expression; Liver-expressed antimicrobial peptide 2; Survival rate