Korea Polar Research Institute (KOPRI) said on the 21st that it has, for the first time in the world, identified the protein that regulates muscle regeneration and growth in Antarctic fish and its operating mechanism.
In medicine, development of treatments for severe muscle wasting "cachexia" caused by aging-related sarcopenia and diseases such as cancer is actively underway. According to the Korea Disease Control and Prevention Agency's 2024 National Health and Nutrition Survey, 1 in 10 people age 65 or older has sarcopenia. But existing candidate substances have been criticized for side effects such as systemic metabolic disorders, insulin resistance, and carcinogenic risk. A new alternative to solve this challenge has been found in Antarctica.
A joint research team led by Kim Jin-hyeong of Korea Polar Research Institute (KOPRI) and Professor Yun Mi-seop of Gachon University confirmed for the first time that "Dnajb5," a type of heat shock protein that protects and repairs damaged parts when cells experience temperature changes or physical shocks, is active in the muscle of the Antarctic black rockcod (Notothenia coriiceps), which inhabits the Antarctic Ocean's extreme low temperatures and high reactive oxygen species environment.
Analysis showed that this protein binds separately to substances that direct protein synthesis or regulate energy production in resting muscle, performing a "dual brake" function that suppresses both pathways at the same time. However, when muscle is damaged or stressed, these binding forces weaken and the brake system is released.
In laboratory mice with actual muscle injury, suppressing Dnajb5 expression increased the cross-sectional area of regenerating myofibers by about 26% compared with the control group, markedly promoting muscle regeneration. Exercise capacity also improved: the experimental group with Dnajb5 suppressed showed a 14% increase in muscle strength (grip strength) versus the control group and endured 31% longer in an endurance test. The research team said this resulted from releasing the two brakes together, simultaneously boosting the muscle's physical strength and intracellular metabolic efficiency.
Kim Jin-hyeong, principal researcher at Korea Polar Research Institute (KOPRI), said, "Dnajb5 is notably abundant specifically in muscle tissue," and added, "If we selectively control only this protein, we may reduce the systemic side effects of existing treatments and safely induce regeneration only in muscle."
The findings were published in the latest issue of the world's leading journal in myology and geriatrics, the Journal of Cachexia, Sarcopenia and Muscle.
Shin Hyeong-cheol, head of Korea Polar Research Institute (KOPRI), said, "This achievement shows that the survival strategies of polar organisms, which have evolved to endure extreme environments, can offer clues to treating intractable human diseases," and evaluated it as "an opportunity to once again confirm the value and potential of polar biological resources."