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The study concludes that cell autophagy preserves the regenerative capacity of stem cells
An international study coordinated by the Cell Biology Group in the Department of Health and Experimental Sciences (DCEXS) at Pompeu Fabra University, led by Pura Muñóz-Cánoves (ICREA researcher), has revealed the key role cell autophagy plays in the muscular regeneration process in ageing.
The study, published in Nature, explains that regeneration of skeletal muscle depends on its stem cells, also known as satellite cells. These cells are held in a state of repose (quiescence) and are activated when tissue is damaged, dividing into new cells that come back together to replace the damaged tissue.
Low-rotation tissues, like skeletal muscle, are normally in a state of quiescence throughout life and it is very important to preserve this state to keep stem cells in good shape so they can do their regenerative function, as head researcher on the study Laura García-Prat explains. However, it has been shown that at an advanced age, the stem cells’ state of rest becomes a state of senescence, in which cells cease to be functional and die; leading to defective muscle regeneration.
The definitive conclusion of the UPF study is that cell autophagy acts as a quality-control mechanism in this process because it is a cell-cleaning system that eliminates damaged organelles and proteins and takes advantage of the useable parts to build new ones. Meaning that it is important for keeping stem cells healthy and suppressing senescence.
Laura García-Prat explains that in order to prove their thesis, the researchers genetically inhibited autophagy in satellite cells in young mice, which caused them to quickly go into a state of senescence. The findings, therefore, open the door to mitigating the loss of regenerative capacity in muscles and improving quality of life for the elderly.
According to the DCEXS researcher, the mechanisms responsible for maintaining the state of quiescence are still unknown, but there are drugs currently being used in clinical trials that can induce autophagy and delay cell ageing. Specifically, the group saw positive results with rapamycin and hopes to continue the research to prove its applications not only in ageing but also to treat Duchenne muscular dystrophy.