How does the body know how old it is? Introducing the epigenetic clock hypothesis.

Author: Mitteldorf JJ.
Affiliation:
Department of EAPS, Massachusetts Institute of Technology, Cambridge, MA 02138, USA. josh@mathforum.org.
Conference/Journal: Biochemistry (Mosc).
Date published: 2013 Sep
Other: Volume ID: 78 , Issue ID: 9 , Pages: 1048-53 , Special Notes: doi: 10.1134/S0006297913090113 , Word Count: 152



Animals and plants have biological clocks that help to regulate circadian cycles, seasonal rhythms, growth, development, and sexual maturity. It is reasonable to suspect that the timing of senescence is also influenced by one or more biological clocks. Evolutionary reasoning first articulated by G. Williams suggests that multiple, redundant clocks might influence organismal aging. Some aging clocks that have been proposed include the suprachiasmatic nucleus, the hypothalamus, involution of the thymus, and cellular senescence. Cellular senescence, mediated by telomere attrition, is in a class by itself, having recently been validated as a primary regulator of aging. Gene expression is known to change in characteristic ways with age, and in particular DNA methylation changes in age-related ways. Herein, I propose a new candidate for an aging clock, based on epigenetics and the state of chromosome methylation, particularly in stem cells. If validated, this mechanism would present a challenging target for medical intervention.
PMID: 24228927

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