Identification and function of an Arasin-like peptide from Litopenaeus vannamei. (December 2021)

• Record Type: Journal Article
• Authors: Zhang, Shuang; Hou, Cuihong; Xiao, Bang; Yao, Yuanmao; Xiao, Wei; Li, Chaozheng; Shi, Lili
• Is Part Of: Developmental and comparative immunology. Volume 125(2021)
• Publication Date: 2021-12
• Subjects: Arasin-like -- Immune response -- Litopenaeus vannamei -- Antibacterial activity -- RNA interference; Immunology -- Periodicals; Developmental immunology -- Periodicals; 616.079
• DOI: 10.1016/j.dci.2021.104174
• Languages: English
• ISSNs: 0145-305X

Abstract

Abstract: Antimicrobial peptides (AMPs) play an important role in the host defense system of shrimps. In this study, an Arasin-like peptide, named as LvArasin-like, was identified from the hemocytes of the pacific white shrimp, Litopenaeus vannamei. The complete open reading frame (ORF) of LvArasin-like was 213 bp, encoding 70 amino acid residues with a predicted molecular mass of 5.68 kDa and a theoretical isoelectric point (p I ) of 6.73. The predicted peptide consisted of a signal peptide, an N-terminal Pro/Arg-rich domain, and a C-terminal cysteine-rich domain. LvArasin-like expression was most abundant in the gills and was up-regulated in hemocytes after LPS or Poly I:C injection as well as challenges by Vibrio parahaemolyticus or Staphylococcus aureus infection. In the heterologous expression system, LvArasin-like protein (rLvArasin-like) was recombinantly expressed in the forms of a dimer or both a monomer and dimer. The rLvArasin-like could directly bind to gram-positive and gram-negative bacteria and exhibited broad-spectrum antimicrobial activity towards them, with 50 % of minimal inhibitory concentrations (MIC50) of 6.25–50 μM. Moreover, dsRNA-mediated knockdown of LvArasin-like enhanced the susceptibility of shrim p to V. parahaemolyticus . In addition, the transcriptional level of LvArasin-like was downregulated when silencing of the transcription factors LvDorsal and LvRelish using RNAi in vivo . All of these results suggest that LvArasin-like is involved in host defense against bacterial infection. Therefore, it is a potential therapeutic agent for disease control in shrimp aquaculture. Highlights: An Arasin-like peptide was identified from Litopenaeus vannamei. Recombinant LvArasin-like could form homodimer. Recombinant LvArasin-like showed broad antimicrobial activity towards bacteria. Knockdown of LvArasin-like enhanced the susceptibility of L. vannamei to V. parahaemolyticus.