Zoological Research ›› 2019, Vol. 40 ›› Issue (2): 94-101.doi: 10.24272/j.issn.2095-8137.2018.062

Special Issue: Amphibians & reptiles Genetics & evolution Toxin & peptide

• Reports • Previous Articles     Next Articles

Identification and characterization of two novel cathelicidins from the frog Odorrana livida

Ruo-Han Qi1,#, Yan Chen1,#, Zhi-Lai Guo1, Fen Zhang1, Zheng Fang1, Kai Huang3, Hai-Ning Yu2,*, Yi-Peng Wang1,*   

  1. 1 College of Pharmaceutical Sciences, Soochow University, Suzhou Jiangsu 215123, China
    2 Department of Bioscience and Biotechnology, Dalian University of Technology, Dalian Liaoning 116023, China
    3 School of Biology & Basic Medical Sciences, Medical College, Soochow University, Suzhou Jiangsu 215123, China
  • Online:2019-03-18 Published:2019-01-11
  • Contact: Hai-Ning Yu,Yi-Peng Wang,E-mail:yuhaining@dlut.edu.cn; yipengwang@suda.edu.cn E-mail:yuhaining@dlut.edu.cn; yipengwang@suda.edu.cn
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Abstract: Antimicrobial peptides (AMPs) are a group of gene-encoded small peptides that play pivotal roles in the host immune system of multicellular organisms. Cathelicidins are an important family of AMPs that exclusively exist in vertebrates. Many cathelicidins have been identified from mammals, birds, reptiles and fish. To date, however, cathelicidins from amphibians are poorly understood. In the present study, two novel cathelicidins (OL-CATH1 and 2) were identified and studied from the odorous frog Odorrana livida. Firstly, the cDNAs encoding the OL-CATHs (780 and 735 bp in length, respectively) were successfully cloned from a lung cDNA library constructed for the frog. Multi-sequence alignment was carried out to analyze differences between the precursors of the OL-CATHs and other representative cathelicidins. Mature peptide sequences of OL-CATH1 and 2 were predicted (33 amino acid residues) and their secondary structures were determined (OL-CATH1 showed a random-coil conformation and OL-CATH2 demonstrated a-helical conformation). Furthermore, OL-CATH1 and 2 were chemically synthesized and their in vitro functions were determined. Antimicrobial and bacterial killing kinetic analyses indicated that OL-CATH2 demonstrated relatively moderate and rapid antimicrobial potency and exhibited strong anti-inflammatory activity. At very low concentrations (10 μg/mL), OL-CATH2 significantly inhibited the lipopolysaccharide (LPS)-induced transcription and production of pro-inflammatory cytokines TNF-a, IL-1b and IL-6 in mouse peritoneal macrophages. In contrast, OL-CATH1 did not exhibit any detectable antimicrobial or anti-inflammatory activities. Overall, identification of these OL-CATHs from O. livida enriches our understanding of the functions of cathelicidins in the amphibian immune system. The potent antimicrobial and anti-inflammatory activities of OL-CATH2 highlight its potential as a novel candidate in anti-infective drug development.

Key words: Antimicrobial peptides (AMPs), Cathelicidins, Odorrana livida, OL-CATHs, Antimicrobial activity, Anti-inflammatory activity

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