Mitochondria as a Key Player in Aging

Abstract

Mitochondrion is an organelle found in eukaryotic cells, which plays a major role in generation of ATP for cell and has its own DNA. Mitochondria are a hub for metabolic activities and signalling pathways and are a key player in the process of aging. ATP generation in mitochondria takes place with the help of electron transport chain and oxidative phosphorylation. Leakage of electrons from the respiratory chain complexes can react with oxygen molecules to give rise to reactive oxygen species (ROS). ROS generated by mitochondria at physiological levels is involved in signalling process and at high levels can cause oxidative damage to cellular proteins, lipids and nucleic acids. Damage to mitochondrial and nuclear genome can give rise to mutations, which can cause gradual deterioration of mitochondrial and cellular function or pathological diseases. Indeed, with aging, the mitochondrial function has been found to deteriorate. There are several quality control pathways to maintain mitochondrial function, which have been shown to be affected during the process of aging. Disruption in mitochondrial protein homeostasis induces mitochondrial unfolded protein response (UPRmt), which enhances the protein-folding capacity of mitochondria. Furthermore, severely damaged mitochondria are removed from the cell by the process of mitophagy. Several genes involved in these processes are implicated in altering the lifespan. In this chapter, we give details of these mitochondrial processes and their implication in aging.