NQO1 from Litopenaeus vannamei involved in the regulation of antioxidant capacity, inflammation, and apoptosis

Abstract

NAD(P)H:quinone oxidoreductase 1 (NQO1) is a versatile FAD-dependent flavoprotein and a key regulator in the Nrf2/ARE signaling pathway. In this study, we cloned the NQO1 gene of Litopenaeus vannamei (LvNQO1) and investigated its role in immune regulation. The results showed that the LvNQO1 gene has an ORF of 987 bp, encoding 328 amino acids. The protein contains an NQO family domain. Homology and phylogenetic analysis revealed that LvNQO1 shares similarities with the NQO1 of Marsupenaeus japonicus, clustering into the same clade. LvNQO1 was expressed in 10 tissues of L. vannamei, with the highest expression in the hepatopancreas and the lowest in the intestine. After RNA interference (RNAi) of LvNQO1, the expression of antioxidant genes (SOD and GST) initially increased but then decreased after 24 h. The expression levels of Gpx and CAT decreased early on but gradually recovered. Immune-related factors (Toll4, JNK, and Hsp90) and apoptosis-related factors (Caspase3, P53, and bcl2) were upregulated. Following RNAi of LvNQO1, Vibrio harveyi challenge significantly increased the expression of immune factors (JNK and HIF1α) and apoptosis factors (Caspase3, P53, and bcl2) in the hepatopancreas. Toll 4 receptors recognized the infection, upregulated their expression, and activated an immune response. RNAi of LvNQO1 led to noticeable histological lesions and apoptosis. These findings suggest that LvNQO1 may play a role in regulating antioxidant capacity, inflammation, and apoptosis in response to Vibrio infection.