Thermal acclimatization mechanisms in the cold-water Ophiuroid Ophiura sarsii vadicola: Regulation of protein homeostasis and metabolic pathways

Global climate change is driving rapid warming in the Pacific Arctic cold-water regions. As dominant species in these areas, the Ophiura sarsii complex suffer from ocean warming stress, resulting in altered distribution patterns, physiological behaviors, and thermotolerance. However, their molecular response mechanisms to ocean warming remain unclear. We conducted transcriptomic analyses of O. sarsii vadicola under various temperature treatments: a control group at in-situ temperature (7 °C), two warming groups at the sub-lethal temperature 19 °C for one week (short-term) and two months (long-term), and a low-temperature reference group of O. sarsii at 0 °C. The results showed that a total of 66 core differentially expressed genes (58 up-regulated, 8 downregulated) were identified, with expression patterns varying by warming duration. Ophiura sarsii vadicola exhibited a more pronounced response to long-term warming than short-term ones. Three transcription factors HMGB3, METTL19, and HEAT were identified as key regulators within the co-expression networks. Furthermore, changes in folding enzymes activity and an upregulation of protein processing and chaperone genes were observed, indicating a potential activation of the unfolded protein response in brittle stars. Elevated temperatures also induced changes in multiple energy metabolism-related pathways. These findings suggest that O. sarsii vadicola may mitigate the negative effects of ocean warming by regulating key gene expression, enhancing protein homeostasis control and energy redistribution. This study provides valuable insights into the evolution and adaptability mechanisms of cold-water species under global climate change.