Identification and Characterization of Heme Oxygenase-1 from Litopenaeus vannamei Involved in Antioxidant and Anti-Apoptosis under Ammonia Stress

Heme oxygenase-1 (HO-1) is a stress-inducible enzyme with antioxidant, anti-inflammatory, and anti-apoptotic effects. In this study, the HO-1 gene from Litopenaeus vannamei (Lv-HO-1) was identified. The open reading frame of Lv-HO-1 is 747 bp, encoding a peptide of 248 amino acids as well as a conserved HemO structural domain. Lv-HO-1 is 70–90% homological to crustaceans and about 50% homological to arthropods. The transcript levels of Lv-HO-1 were highest in the hepatopancreas and lower in other tissues. Knockdown of Lv-HO-1 led to structural destruction of the hepatopancreas. After ammonia exposure, Lv-HO-1 was significantly induced. Knockdown of Lv-HO-1 during ammonia exposure resulted in a significant decrease in antioxidant capacity and cellular autophagy levels compared to the control and increased apoptosis. The transcriptional levels of SOD and GSH-Px were considerably reduced (p < 0.05), as were the transcriptional levels of Atg3, Atg4, Atg5, and Atg10. The results indicated that Lv-HO-1 from L. vannamei can be induced by oxidative stress and may have important roles in regulating the host antioxidant system, reducing cell apoptosis.