Abstract
Increasing pressures on aquatic ecosystems because of pollutants, nutrient enrichment, and global warming have severely depleted oxygen concentrations. This sudden and significant lack of oxygen has resulted in persistent increases in fish mortality rates. Revealing the molecular mechanism of fish hypoxia adaptation will help researchers to find markers for hypoxia induced by environmental stress. Here, we used a multiomics approach to identify several hypoxia-associated miRNAs, mRNAs, proteins, and metabolites involved in diverse biological pathways in the muscles of Pelteobagrus vachelli. Our findings revealed significant hypoxia-associated changes in muscles over 4 h of hypoxia exposure and discrete tissue-specific patterns. We have previously reported that P. vachelli livers exhibit increased anaerobic glycolysis, heme synthesis, erythropoiesis, and inhibit apoptosis when exposed to hypoxia for 4 h. However, the opposite was observed in muscles. According to our comprehensive analysis, fishes show an acute response to hypoxia, including activation of catabolic pathways to generate more energy, reduction of biosynthesis to decrease energy consumption, and shifting from aerobic to anaerobic metabolic contributions. Also, we found that hypoxia induced muscle dysfunction by impairing mitochondrial function, activating inflammasomes, and apoptosis. The hypoxia-induced mitochondrial dysfunction enhanced oxidative stress, apoptosis, and further triggered interleukin-1β production via inflammasome activation. In turn, interleukin-1β further impaired mitochondrial function or apoptosis by suppressing downstream mitochondrial biosynthesis-related proteins, thus resulting in a vicious cycle of inflammasome activation and mitochondrial dysfunction. Our findings contribute meaningful insights into the molecular mechanisms of hypoxia, and the methods and study design can be utilized across different fish species.