A research team led by Seung Jae Lee of the Department of Biological Sciences has recently discovered the role of Mediator 15 (MDT-15 or MED 15) and oleic acid, organic materials essential to proteostasis, in the longevity of certain organisms.
Biological mechanisms are easily influenced by the temperature of the environment — low temperatures promote longevity in many organisms. Because this tendency is widely observed amongst many dissimilar species, the effect of temperature on longevity is thought to be related to a fundamental mechanism of life.
The research team established that a transcriptional coregulator, MDT-15, is essential for low-temperature longevity and proteostasis. Proteostasis is the cell’s tendency to maintain protein integrity and lower the stress that the cell receives to keep the organism healthy. In their experiment, it was found that roundworms (C. elegans) that had the modified MDT-15 gene necessary for protein translation had a shorter lifespan.
The role of MDT-15 is the up-regulation of fat-7, which converts unsaturated fatty acids to saturated fatty acids at low temperatures, leading to proteostasis. Fat-7 is therefore crucial to maintaining proteostasis. MDT-15 also catalyzes chaperones in the cytoplasm, which are crucial to maintaining the integrity of proteins translated, another key factor in proteostasis.
Furthermore, MDT-15 participates in the production of oleic acid, a type of unsaturated fatty acid. Lee’s research team found that a shorter lifespan and loss of protein integrity in C.elegans in low temperatures can be mediated by providing oleic acid to the creatures. This again increases the ratio of unsaturated to saturated fatty acids, improving the longevity.
Having more saturated fatty acid has been related to many human diseases as well. Amongst others, high blood pressure and heart disease display this correlation. Patients suffering from Alzheimer’s disease display a low ratio of unsaturated to saturated fatty acids in the brain, which may create a toxic environment for the cells and lead to deterioration of brain function.
Lee’s research team hopes to further reveal the mechanics of longevity and apply it to humans. The findings of this research were published on August 13 in PLOS Biology.