Characterization of grass carp (Ctenopharyngodon idella) beta-defensin 1: implications for its role in inflammation control

ABSTRACT

Considering that fish grows in a complex aquatic environment, there is an increasing interest in fish β-defensins, which is an important group of antimicrobial peptides (AMPs). In this study, grass carp (Ctenopharyngodon idella) β-defensin 1 (gcdefb1) was isolated using homology cloning technology. Tissue distribution assay showed that gcdefb1 transcripts were expressed with the highest levels in brain and liver, followed by some mucous tissues. To examine gcDefb1 bioactivities, the recombinant gcDefb1 proteins fused with thioredoxin tag protein (Trx) (Trx-Defb1) were induced for production in Escherichia coli Rosetta-gami2(DE3)pLysS under optimal expression conditions. The antibacterial activity of Trx-Defb1 against Aeromonas hydrophila was assessed and its minimum inhibitory concentration (MIC) was 36 μM. Interestingly, Trx-Defb1 significantly inhibited LPS-induced Tnf-α (gcTnf-α) secretion and nitric oxide production in grass carp head kidney monocytes/macrophages (HKM), although Trx-Defb1 alone had no effect. Our studies provide the first evidence of fish β-defensin 1 engaging in both antimicrobial and inflammation suppression process.

Graphical Abstract

Dual role of grass carp Defb1 in inflammation control via antimicrobial activity against pathogen and immuno-suppressive modulation for host.

KEYWORDS:

• Grass carp
• β-defensin 1
• antimicrobial activity
• immuno-suppressive modulation
• inflammation control

Author contribution

Conceived and designed the experiments: Taiqiang Zhao, Kun Yang and Fangfang Ren. Performed the experiments: Boren Hou and Kun Yang. Analyzed the data: Taiqiang Zhao, Kun Yang and Fangfang Ren. Wrote the paper: Taiqiang Zhao, Kun Yang and Hong Zhou.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by the National Natural Science Foundation of China (NSFC) [grant numbers 31602192 and 31572650] and Fundamental Research Funds for the Central Universities in UESTC [grant number ZYGX2015J090].