The Dual Nature of Reactive Oxygen Species in Aging

Reactive oxygen species (ROS) are largely generated in the mitochondria of the cell, a side-effect of the energetic processes taking place there to power cellular operations. ROS cause damage that must be repaired by reacting with molecular machinery in the cell, and that stress on the cell increases with age, and features prominently in most discussions of aging. ROS also play an important role as signals, however, triggering important processes related as cellular maintenance. That exercise is beneficial, for example, depends upon an increase in ROS production, and a number of ways of increasing life span in laboratory species incorporate some degree of increased ROS generation. Historically, mitochondrial ROS (mtROS) production and oxidative damage have been associated with aging and age-related diseases. In fact, the age-related increase in ROS has been viewed as a cause of the aging process while mitochondrial dysfunction is considered a hallmark of aging, as a consequence of ROS accumulation. However, pioneering work in Caenorhabiditis elegans has shown that mutations in genes encoding subunits of the electron transport chain (ETC) or genes required for biosynthesis of ubiquinone extend lifespan despite reducing mitochondrial function. The lifespan extension conferred by many of these alterations is ROS dependent, as reduction of ROS abolishes this effect. Moreover, chemical inhibition of glycolysis or exposure to metabolic poisons that block respiratory comple...
Source: Fight Aging! - Category: Research Authors: Tags: Daily News Source Type: blogs