Arylsulfatase LvArs2 regulates glycosaminoglycan sulfation and modulates white spot syndrome virus burden in Litopenaeus vannamei

Glycosaminoglycans (GAGs) and their sulfation patterns are pivotal in determining barrier tissue homeostasis and pathogen interactions in crustaceans. However, the underlying enzymatic regulators remain to be fully elucidated. In this study, we have identified and curated eight arylsulfatase (ARS) genes in the Pacific white shrimp ( Litopenaeus vannamei ), with a particular focus on LvARS2, among the most abundant transcript in the hepatopancreas. The investigation revealed that LvARS2 exhibits a lysosomal-type profile, with maximal activity at a pH of 5.0 and 40 °C, strong Ca²⁺ dependence, and a conserved formylglycine (FGly) catalytic centre. In vivo assays demonstrated that LvArs2 knockdown was associated with elevated sulfated GAG (sGAG) and higher WSSV burden. Conversely, recombinant enzyme treatment reduced sGAG accumulation and viral load. A rescue design was employed to restore control phenotypes partially. Collectively, these results support LvARS2 as an ARSB-type arylsulfatase that modulates the overall tissue sGAG signal measured by DMMB, thereby associating extracellular matrix chemistry with viral susceptibility. This study provides a mechanistic link between ARS activity, GAGs metabolism, and immune defence in crustaceans. It suggests the potential of enzyme-based modulation of sulfation as a complementary strategy for disease control in aquaculture. • Eight arylsulfatase (ARS) genes were identified in the genome of Litopenaeus vannamei. • LvARS2 shows high expression in hepatopancreas and exhibits lysosomal-type enzymatic properties. • LvARS2 knockdown increased sulfated glycosaminoglycan (sGAG) accumulation and WSSV load. • R- Lv ARS2 treatment reduced sGAG levels and viral burden. • LvARS2 modulates WSSV susceptibility through regulation of GAG sulfation.