A Glutathione Peroxidase Gene from Litopenaeus vannamei Is Involved in Oxidative Stress Responses and Pathogen Infection Resistance.

Jinquan Fan,Guoliang Chen,Yihong Chen,Kecheng Lu,Zeyu Yan,Binbin Li,Xinjun Yang,Lei Wang,Qianming Hong

doi:10.3390/ijms23010567

Abstract

In shrimp, several glutathione peroxidase (GPX) genes have been cloned and functionally studied. Increasing evidence suggests the genes’ involvement in white spot syndrome virus (WSSV)- or Vibrio alginolyticus-infection resistance. In the present study, a novel GXP gene (LvGPX3) was cloned in Litopenaeus vannamei. Promoter of LvGPX3 was activated by NF-E2-related factor 2. Further study showed that LvGPX3 expression was evidently accelerated by oxidative stress or WSSV or V. alginolyticus infection. Consistently, downregulated expression of LvGPX3 increased the cumulative mortality of WSSV- or V. alginolyticus-infected shrimp. Similar results occurred in shrimp suffering from oxidative stress. Moreover, LvGPX3 was important for enhancing Antimicrobial peptide (AMP) gene expression in S2 cells with lipopolysaccharide treatment. Further, knockdown of LvGPX3 expression significantly suppressed expression of AMPs, such as Penaeidins 2a, Penaeidins 3a and anti-lipopolysaccharide factor 1 in shrimp. AMPs have been proven to be engaged in shrimp WSSV- or V. alginolyticus-infection resistance; it was inferred that LvGPX3 might enhance shrimp immune response under immune challenges, such as increasing expression of AMPs. The regulation mechanism remains to be further studied.

Highlights

Glutathione peroxidases (GPXs) belong to a family of phylogenetically related oxidoreductases distributed in all living domains
LvGPX3 possessed a conserved GSHPx domain (Figure 1A), which is commonly found in GPXs and is the feature of enzymes catalyzing the reduction of hydroxyperoxides by glutathione
LvGPX3 was induced by the shrimp pathogens white spot syndrome virus (WSSV) or V. alginolyticus

Summary

Introduction

Glutathione peroxidases (GPXs) belong to a family of phylogenetically related oxidoreductases distributed in all living domains. They are selenium-dependent hydroperoxidasereducing enzymes that contribute to removing lipid hydroperoxide, eliminating H2O2, reducing damage of organic hydroperoxides and so on [1]. Cytosolic GPXs mainly catalyze GSH, which participates in peroxidation and scavenges peroxides and hydroxyl radicals produced in cell respiration and metabolism, reducing the peroxidation of polyunsaturated fatty acids in cell membrane, which is very important [2]. Plasma GPXs have been shown to be involved in the removal of extracellular hydrogen peroxide and participation in the transport of GSH [5].

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Conclusion