Role of the Dissostichus mawsoni LeptinB Gene in Cellular Cold Resistance

Variation in fish temperature is determined by changes in the external aquatic environment, and temperature serves as a crucial regulatory factor for the behavior, physiology, and molecular processes of fish. A rapid decline in water temperature can elicit a strong stress response in fish, potentially inhibiting growth and even leading to mortality. Low temperature stress significantly impacts various life processes of organisms, including growth and development, energy metabolism, and reproductive development. In recent years, there has been increasing research on the effects of low-temperature stress on organisms, with a greater focus at the molecular level. Low temperatures induce a decrease in cellular activity and even growth arrest, resulting in apoptosis. Apoptosis is a form of programmed cell death ubiquitous in the biological world, and it plays a vital role in maintaining the normal physiological function of an organism. Once apoptosis occurs, it is irreversible and cannot be stopped. Temperature regulation is crucial for fish, and current knowledge of the role of leptin in fish primarily focuses on the regulation of feeding, lipid energy metabolism, and reproduction, with limited reports on its role in temperature regulation.Leptin, a protein hormone produced by adipocytes, has long been recognized as a product of the obese gene, which regulates organismal metabolism, neuroendocrine function, and other physiological processes. In animals, it exerts diverse physiological functions related to cell growth, proliferation, apoptosis, and metabolism. The homology of the leptin gene in fish is relatively low compared to that in mammals, and multiple leptin proteins encoded by multiple leptin genes can be produced due to genomic duplication events. Regarding the role of leptin in temperature regulation, more research has been conducted on mammals, mainly related to the regulation of energy metabolism and the influence on temperature adaptation evolution. There has been limited research on the regulatory mechanism of leptin in fish during cold stress.Dissostichus mawsoni belongs to the group of Antarctic vertebrates and has lived in the cold and isolated environment of the Southern Ocean at a temperature of –1.9 ℃ for ~30 million years. It has adapted to the extremely low temperatures of the surrounding Antarctic waters and is an excellent material and living fossil for studying temperature adaptation mechanisms in extreme environments. Compared with oth