Proteomic analysis of Eriocheir sinensis hemocytes in response to hypoxia stress

Abstract The Chinese mitten crab, Eriocheir sinensis, is an important economic aquatic product in China. Oxygen is essential for the crab, hypoxia is a natural phenomenon common in the process of aquaculture and will bring a harmful impact on the growth, development and disease outbreak of crab. To understand the effect of hypoxia on the crab, the proteome changes of E. sinensis hemocytes in the hypoxia (1.5 ± 0.5 mg/L of DO) and the normoxia groups (6.0 ± 0.5 mg/L of DO) were obtained using iTraq labeling and affinity enrichment followed by high-resolution LC-MS/MS analysis. In total, 664 differentially expressed proteins were reliably quantified (567 up-regulated and 97 down-regulated) using 1.2-fold change in expression as a physiologically significant benchmark. GO annotation, KEGG annotation, etc. were used to analysis these significantly different expression proteins. Many pathways or biological process were identified in the process of E. sinensis hemocytes response hypoxia, such as tricarboxylic acid (TCA) cycle, cell apoptosis, VEGFR/MAPK pathway, prophenoloxidase system (proPO system), phagocytosis, and so on. Ten selected genes from these different expression proteins were verified by qRT-PCR analysis. Finally, the activity of several major antioxidant enzymes (phenoloxidase (PO), superoxide dismutase (SOD), catalase (CAT) and malondialdehyde (MDA)) were analysis, the results showed that hypoxia stress significantly increased these enzymes activity. These study could serve as a basis to understand the relationship between E. sinensis hemocytes and hypoxia stress, and also provide reference to study hypoxia stress in other crustaceans.