Major differences in gene activity in skeletal muscle of women and men
A comprehensive study of gene activity in skeletal muscle at Karolinska Institutet has shown that thousands of genes are expressed differently in women’s and men’s muscles. The study, which is published in the FASEB Journal, provides a clearer picture of healthy muscle tissue, which in the long-term could help us better understand a number of different medical conditions where skeletal muscle has an important role.
"I hope that the gene activity results from this study will become a reference for human skeletal muscle and provide the basis for many new studies investigating skeletal muscle in different diseases and dysfunctions. In that way, we can understand our muscles better and possibly develop more optimal treatments and a more personalized health care," says first study-author Maléne Lindholm, a Doctoral student in Professor Carl Johan Sundberg’s research team at the Department of Physiology and Pharmacology.
In the study, researchers analysed whole transcriptomes of human skeletal muscle. When a gene is active, it produces transcripts which act as templates for the production of proteins, the functional molecules in cells. The transcriptome is a collection of all transcripts found in human tissue at a given point in time and provides an indication of how active the different genes are.
The researchers took small muscle samples from both legs of healthy volunteers, nine women and nine men. When they compared the transcriptome in skeletal muscles from both sexes they found 1,700 genes which are more active in men and 1,300 which are more active in women. They noticed that the transcriptome in both the legs of one individual is very similar, which was unclear before. The researchers also found entirely new transcripts.
Essential for our well-being
Fully-functional skeletal muscles are essential for our well-being. Our muscles also play an important role in a number of diseases such as type 2 Diabetes and cardiovascular disease. In order to understand how the muscles malfunction during disease, researchers first need to know how a normal muscle works. It is also important to take into account the major differences between men and women when developing future strategies for the treatment of these diseases.
In addition to the above-mentioned diseases, the results could also become of future importance for medical conditions where there is muscle loss such as muscular dystrophy, sarcopenia and obesity. The study was funded by grants from the Swedish National Centre for Research in Sports and Wallenberg Advanced Bioinformatics Infrastructure. Researchers from SciLifeLab, Stockholm University and KTH also took part in the study.
Text: Karin Söderlund Leifler (in translation from Swedish)
The human skeletal muscle transcriptome: sex differences, alternative splicing, and tissue homogeneity assessed with RNA sequencing
Malene E. Lindholm, Mikael Huss, Beata W. Solnestam, Sanela Kjellqvist, Joakim Lundeberg, and Carl J. Sundberg
The FASEB Journal, October issue 2014, online 11 July 2014