Muscle atrophy caused by weightlessness is similar to the muscle wasting caused by disuse on Earth. Dr. Marc T. Hamilton is examining the effects of muscle disuse through human trials involving one-leg bicycle exercises, and he is investigating the effects of muscle disuse on genetic expression in rats after periods of exercise and inactivity. This research will provide knowledge of the physical effects of muscle disuse and is measuring how all of the approximately 35,000 genes in the human genome are adversely affected by physical inactivity.
Genomics of Human Skeletal Muscle During Bed Rest and Exercise
Marc T. Hamilton, Ph.D.
University of Missouri
Additionally, large scale genomic studies are likely to begin to reveal clusters of related mRNAs that provide clues as to the sets of genes orchestrating some of the cellular signaling, transcriptional changes, cellular growth and metabolism. This project will build upon recent experience established from microarray studies of hindlimb suspension, endurance exercise and muscle fiber type that support the statements described above. The effects of bed rest and one-leg exercise (as a countermeasure to attenuate the effects of inactivity) on the soleus muscle of six men and six women will be studied.
Using state-of-the-art microarray methodologies, this project will measure the expression of approximately 12,000 full-length. Sequence verified mRNAs and approximately 3,000 of the most abundant muscle ESTs. This project is being proposed by a laboratory already using microarrays in the study of muscle physiology, in collaboration with a bioinformatics laboratory, a physical therapy laboratory focused on muscle function, a physician-scientist studying muscle diseases and a core laboratory for microarray development. This study is likely to discover novel candidate genes and clusters of related genes potentially responsible for the unhealthy responses to reduced muscle use during physical inactivity.