News from CEXS-UPF
The ability for skeletal muscle to regenerate depends on its stem cells, known as satellite cells, which are found in a resting state (quiescence) and are activated when damage occurs to the tissues. In tissues with little turnover, as is the case of skeletal muscle, this state of reversible quiescence is the normal state throughout one's lifetime. However, recent studies show that at geriatric ages, the normal resting state of the stem cells is substituted by a state of irreversible senescence, which results in a numerical and functional decrease in these satellite cells and a failure in muscle regeneration.
Although the mechanisms responsible for maintaining this quiescence, the preservation of the "bag" of stem cells, and the prevention of senescence during an individual's lifetime remain unknown, research published in Nature coordinated by Pura Muñoz Cánoves, ICREA researcher and leader of the Cell Biology Unit at the Department of Experimental and Health Sciences (DCEXS) and CIBERNED member, has revealed the key role that autophagy, the mechanism by which cells are cleaned of toxic waste (damaged proteins and organelles) and maintain their internal equilibrium (cell homeostasis), plays in this process.
As Pura Muñoz-Cánoves says, "this work identifies the failure of autophagy as a determining factor of the regenerative capacity in muscle stem cells in the aged". "As autophagy mechanisms have also been found deregulated in geriatric human muscle cells", she adds, "these findings open the doors to investigation focused on attenuating the loss of regenerative capacity of the muscle in elderly people, which would give them greater independence and a better quality of life".
Laura García-Prat, Marta Martínez-Vicente, Eusebio Perdiguero, Laura Ortet, Javier Rodríguez-Ubreva, Elena Rebollo, Vanessa Ruiz-Bonilla, Susana Gutarra, Esteban Ballestar, Antonio L. Serrano, Marco Sandri & Pura Muñoz-Cánoves. Autophagy maintains stemness by preventing senescence . Nature January 2016. doi:10.1038/nature16187