Insights into the Response in Digestive Gland of Mytilus coruscus under Heat Stress Using TMT-Based Proteomics

SIMPLE SUMMARY: High-temperature stimulation can lead to severe stress response and affect the normal physiological function of animals. Generally, animals respond to the stimulation of extreme environments by regulating their physiological functions, including energy metabolism, biofactor synthesis, and degradation. The results of this study suggest that marine animals may respond to heat stress by regulating oxidative stress-related enzymes and basic metabolic levels. ABSTRACT: Ocean warming can cause injury and death in mussels and is believed to be one of the main reasons for extensive die-offs of mussel populations worldwide. However, the biological processes by which mussels respond to heat stress are still unclear. In this study, we conducted an analysis of enzyme activity and TMT-labelled based proteomic in the digestive gland tissue of Mytilus coruscus after exposure to high temperatures. Our results showed that the activities of superoxide dismutase, acid phosphatase, lactate dehydrogenase, and cellular content of lysozyme were significantly changed in response to heat stress. Furthermore, many differentially expressed proteins involved in nutrient digestion and absorption, p53, MAPK, apoptosis, and energy metabolism were activated post-heat stress. These results suggest that M. coruscus can respond to heat stress through the antioxidant system, the immune system, and anaerobic respiration. Additionally, M. coruscus may use fat, leucine, and isoleucine to meet energy requirements under high temperature stress via the TCA cycle pathway. These findings provide a useful reference for further exploration of the response mechanism to heat stress in marine mollusks.