Comparative proteomic study of the response to hypoxia in the muscle of oriental river prawn (Macrobrachium nipponense).

Adaptation to hypoxia is a complex process involving up- or down-regulation of numerous different proteins. In order to understand the molecular responses to hypoxia in crustacean muscle tissue, flow cytometry and oxidative stress analysis were used to explore the (hypoxia) physiological response on Macrobrachium nipponense. A 2D-gel-based proteomic approach was performed to compare the muscle proteome of hypoxic and normoxic M. nipponense. MALDI-TOF/TOF identified 15 and five proteins were significantly up- and down-regulated, respectively, in M. nipponense muscle under hypoxic conditions for 24h. Five spots were confirmed as hemocyanin, indicating an important role in environmental regulation. Real-time quantitative PCR confirmed that hemocyanin, heat shock protein 70, glutathione S-transferases, metallothionein, phosphofructokinase, and pyruvate kinase 2 were all up-regulated by hypoxia stress. These results suggest that the cellular response to hypoxia involves regulating proteins that function in maintaining antioxidative capacity, energy levels and muscle structure. Western blotting confirmed that the well-known hypoxic stress markers hemocyanin and heat shock protein 70 were up-regulated. These results increase our understanding of hypoxia-induced proteomic and transcriptional changes in M. nipponense muscle tissue. BIOLOGICAL SIGNIFICANCE: This 2-DE proteomic study investigated differentially expressed proteins in the muscle of prawns following hypoxia. Identified proteins may have roles in the response to hypoxia. These results improve our understanding of hypoxic stress in crustaceans and aquatic ecosystems.