Proteostasis collapse, inter-tissue communication, and the regulation of aging at the organismal level
What is the nature of the molecular and cellular mechanisms that drive the aging process is a puzzling unsolved enigma that has been under debate for decades. Several prominent theories have been proposed to explain the mechanistic basis of aging. Late in the nineteenth century, the German biologist August Weismann noticed that the lifespans of different species, which live in similar environments, differ greatly. Based on this observation he predicted that the duration of an animal's life is set by internal organismal components rather than external factors (Weismann, 1889). In modern terms this theory suggests that the pace of aging is governed by the activity of biological mechanisms such as signaling cascades that control the expression of gene networks, post-translational modifications or epigenetic factors. The rationale underlying this theory suggests that aging is a regulated, programmed process which is amenable to the activity of specialized mechanisms.