RNAi screening identifies a new Toll from shrimp Litopenaeus vannamei that restricts WSSV infection through activating Dorsal to induce antimicrobial peptides

Different shrimp species are known to possess apparent distinct resistance to different pathogens in aquaculture. However, the molecular mechanism underlying this finding still remains unknown. One kind of important antimicrobial peptides, anti-lipopolysaccharide factors (ALF), exhibit broad-spectrum antimicrobial activities. Here, we reported a newly identified ALF from the shrimp Litopenaeus vannamei and compared the immune function with its counterpart in the shrimp Fenneropenaeus chinensis. The ALF, designated as LvALF8, was specifically expressed in the lymphoid organ of L. vannamei. The expression level of LvALF8 was apparently changed after white spot syndrome virus (WSSV) or Vibrio parahaemolyticus challenges. The synthetic LBD peptide of LvALF8 (LvALF8-LBD) showed strong antibacterial activities against most tested Gram-negative and Gram-positive bacteria. LvALF8-LBD could also inhibit the in vivo propagation of WSSV similar as FcALF8-LBD, the LBD of LvALF8 counterpart in F. chinensis. However, LvALF8-LBD and FcALF8-LBD exhibited apparently different antibacterial activity against V. parahaemolyticus, the main pathogen causing acute hepatopancreatic necrosis disease (AHPND) of affected shrimp. A structural analysis showed that the positive net charge and amphipathicity characteristics of LvALF8-LBD peptide were speculated as two important components for its enhanced antimicrobial activity compared to those of FcALF8-LBD. These new findings may not only provide some evidence to explain the distinct disease resistance among different shrimp species, but also lay out new research ground for the testing and development of LBD-originated antimicrobial peptides to control of shrimp diseases.

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RNAi knock-down of shrimp Litopenaeus vannamei Toll gene and immune deficiency gene reveals their difference in regulating antimicrobial peptides transcription

Developmental & Comparative Immunology ◽

10.1016/j.dci.2014.01.004 ◽

2014 ◽

Vol 44 (2) ◽

pp. 255-260 ◽

Cited By ~ 42

Author(s):

Fujun Hou ◽

Shulin He ◽

Yongjie Liu ◽

Xiaowen Zhu ◽

Chengbo Sun ◽

...

Keyword(s):

Immune Deficiency ◽

Antimicrobial Peptides ◽

Litopenaeus Vannamei ◽

Knock Down ◽

Deficiency Gene

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Specific Molecular Signatures for Type II Crustins in Penaeid Shrimp Uncovered by the Identification of Crustin-Like Antimicrobial Peptides in Litopenaeus vannamei

Marine Drugs ◽

10.3390/md16010031 ◽

2018 ◽

Vol 16 (1) ◽

pp. 31 ◽

Cited By ~ 10

Author(s):

Cairé Barreto ◽

Jaqueline Coelho ◽

Jianbo Yuan ◽

Jianhai Xiang ◽

Luciane Perazzolo ◽

...

Keyword(s):

Antimicrobial Peptides ◽

Litopenaeus Vannamei ◽

Penaeid Shrimp ◽

Molecular Signatures ◽

Type Ii

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RNAi screening identifies a new Toll from shrimp that restricts WSSV infection through activating Dorsal to induce antimicrobial peptides

10.1101/365197 ◽

2018 ◽

Author(s):

Haoyang Li ◽

Bin Yin ◽

Sheng Wang ◽

Qihui Fu ◽

Bang Xiao ◽

...

Keyword(s):

Transcription Factor ◽

Antiviral Activity ◽

Antimicrobial Peptides ◽

Nuclear Translocation ◽

Structural Proteins ◽

Toll Pathway ◽

Antiviral Immune Response ◽

Rnai Screening ◽

Dorsal Pathway

ABSTRACTThe function of Toll pathway defense against bacterial infection has been well established in shrimp, however how this pathway responds to viral infection is still largely unknown. In this study, we report the Toll4-Dorsal-AMPs cascade restricts the white spot syndrome virus (WSSV) infection of shrimp. A total of nine Tolls from Litopenaeus vannamei namely Toll1-9 are identified, and RNAi screening in vivo reveals the Toll4 is important for shrimp to oppose WSSV infection. Knockdown of Toll4 results in elevated viral loads and renders shrimp more susceptible to WSSV. Furthermore, Toll4 could be a one of upstream pattern recognition receptor (PRR) to detect WSSV, and thereby leading to nuclear translocation and phosphorylation of Dorsal, the known NF-κB transcription factor of the canonical Toll pathway. More importantly, silencing of Toll4 and Dorsal contributes to impaired expression of a specific set of antimicrobial peptides (AMPs) such as anti-LPS-factor (ALF) and lysozyme (LYZ) family, which exert potent anti-WSSV activity. Two AMPs of ALF1 and LYZ1 as representatives are demonstrated to have the ability to interact with several WSSV structural proteins. Taken together, we therefore identify the Toll4-Dorsal pathway mediates strong resistance to WSSV infection by inducing some specific AMPs.Author summaryThe TLR pathway mediated antiviral immune response is well identified in mammals, yet, Toll pathway governing this protection in invertebrates remains unknown. In the present study, we uncover that a shrimp Toll4 from a total of nine Tolls in L. vannamei confers resistance to WSSV thought inducing the NF-κB transcription factor Dorsal to inspiring the production of some antimicrobial peptides (AMPs) with antiviral activity. The anti-LPS-factor (ALF) and lysozyme (LYZ) family are identified as the Toll4-Dorsal pathway targeted genes with the ability to interact with viral structural proteins in response to WSSV infection. These results suggest that the Toll receptor induces the expression of AMPs with antiviral activity could be a general antiviral mechanism in invertebrates and Toll pathway established antiviral defense could be conserved during evolution.

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