Aging: Molecular Pathways and Implications on the Cardiovascular System

Figure 6

Role of autophagy as cellular scavengers. Autophagy is mainly regulated by two energy sensors: mTOR and AMPK. mTOR is an inhibitor of autophagy and is activated when there are abundant cellular nutrients. AMPK is activated when nutrients deplete, inducing autophagy by inhibiting mTOR, as well as direct activation of autophagy. This mechanism is important for cell “cleaning,” degrading damaged organelles, protein aggregates, and other cellular toxic components. After the formation of the autophagosome, there is fusion with the lysosome, occurring the cleavage of the degraded material. There are two other types of autophagy: microautophagy, with direct involvement of the material by the lysosome. In addition, there is a chaperone-mediated autophagy, encompassing the material via the LAMP-2A receptor. Together, these mechanisms improve metabolism, being an energy source through recycling amino acids and, eventually, participating in cellular quality control, which promotes an improvement in the individual lifespan and healthspan.