Long-term PGC1β overexpression leads to apoptosis, autophagy and muscle wasting

5 years ago

Long-term PGC1β overexpression leads to apoptosis, autophagy and muscle wasting

Vihang A. Narkar, Eun Ran Kim, Isabelle K. Vila, Neah Likhite, Min Sup Song, Qingchun Tong, Vikas Yadav, Danesh H. Sopariwala, George G. Rodney, Megha Sheth, Pierre-Marie Badin, Sabina Lorca

Skeletal muscle wasting is prevalent in many chronic diseases, necessitating inquiries into molecular regulation of muscle mass. Nuclear receptor co-activator peroxisome proliferator-activated receptor co-activator 1 alpha (PGC1α) and its splice variant PGC1α4 increase skeletal muscle mass. However, the effect of the other PGC1 sub-type, PGC1β, on muscle size is unclear. In transgenic mice selectively over-expressing PGC1β in the skeletal muscle, we have found that PGC1β progressively decreases skeletal muscle mass predominantly associated with loss of type 2b fast-twitch myofibers. Paradoxically, PGC1β represses the ubiquitin-proteolysis degradation pathway genes resulting in ubiquitinated protein accumulation in muscle. However, PGC1β overexpression triggers up-regulation of apoptosis and autophagy genes, resulting in robust activation of these cell degenerative processes, and a concomitant increase in muscle protein oxidation. Concurrently, PGC1β up-regulates apoptosis and/or autophagy transcriptional factors such as E2f1, Atf3, Stat1, and Stat3, which may be facilitating myopathy. Therefore, PGC1β activation negatively affects muscle mass over time, particularly fast-twitch muscles, which should be taken into consideration along with its known aerobic effects in the skeletal muscle.

Publisher URL: https://www.nature.com/articles/s41598-017-10238-9

DOI: 10.1038/s41598-017-10238-9