New gene variant could lead to future treatments for muscle loss in elderly

A new study by the Norwegian University of Science and Technology identified an exercised-induced RNA strand which was shown to mitigate muscle loss and aging in both mice and roundworms.

The study, published in Science Translation Medicine, was led by Martin Wohlwend, PhD. Wohlwend and his team of researchers set out to learn more about the role that long noncoding RNAs (IncRNAs) play in changes to the skeletal muscle. To begin, scientists used a gene editing system known as CRISPR-Cas9, and in the dark genetic material in skeletal muscle cells, they identified the IncRNA, CYTOR.

Upon further investigation, researchers found that CYTOR levels drop in humans as they age. In addition, their experiments on mice indicated the CYRTOR levels contribute to the development of type II or “fast twitch” muscle fibres, used for anaerobic exercise. The loss of fast twitch muscle fibres is also associated with aging.

“The CYTOR gene seems to be absolutely crucial in order to maintain normal muscle function,” Wohlwend said.

Next, the researchers used gene therapy to increase the production of CYTOR in mice. Results showed that mice with increased CYTOR production improved muscle function. In aging mice, the increased CYTOR expression enhanced muscle mass, running capacity, and grip strength. When scientists reduced CYTROR expression in younger mice, their muscles weakened and their levels of inflammation and muscle cell deaths increased.

To gain more insight into how CYTOR effects aging, researchers cloned the IncRNA into roundworms (Caenorhabditis elegans), which age rapidly. Worms with the CYTOR had better muscle function and faster movement than worms without the gene.

This study suggests that increased expression of CYTOR mitigates muscle loss associated with aging, paving the way for new treatments for muscle loss in the elderly.