Mass Spectrometric Profiling of Neuropeptides in Callinectes sapidus during Hypoxia Stress

Oxygen (O2) is a critical component of life; without proper O2 levels, cells are unable to respire, meaning glucose cannot be utilized. Thus, hypoxia (low O2 levels) is a well-documented stressor, especially in aquatic environments. Neuropeptides are a major class of regulators for stress-induced responses; however, their global expression changes during stress are not well characterized due to the natural complexity of the nervous system. Beyond being a neurological model organism, crustaceans are regularly exposed to hypoxia, making them a relevant system for this study. Several neuropeptide families, including orcokinins, RFamides, and allatostatin A-types, show dynamic dysregulation due to hypoxic stress. In particular, the brain showed the most dynamic changes with a survival mechanism “switching” (i.e., significant increase to decrease) of neuropeptide content between moderate and severe hypoxia (e.g., NFDE­DRSGFA, FDAF­TTGF­GHS, NRN­FLRF­amide, and APSG­FLGMR­amide). Globally, neuropeptides in different tissues appeared to exhibit unique expression patterns at the various severities of hypoxia, including LSSS­NSPS­STPL and NFDE­IDRS­SFGF. Overall, this study provides clear evidence for the benefits of globally analyzing biomolecules and that neuropeptides play a critical role in how crustaceans adapt due to hypoxic stress.