How is senscent to be measured or are senscent cells to get counted ?
How are senescent developments to be evaluated ?
Is there a relation between senescence and telomere-length ?
Answers
Explanation:
Telomeres are protective structures present at the ends of linear chromosomes that are important in preventing genome instability. Telomeres shorten as a result of cellular replication, leading to a permanent cell cycle arrest, also known as replicative senescence. Senescent cells have been shown to accumulate in mammalian tissue with age and in a number of age-related diseases, suggesting that they might contribute to the loss of tissue function observed with age. In this review, we will first describe evidence suggesting a key role for senescence in the ageing process and elaborate on some of the mechanisms by which telomeres can induce cellular senescence. Furthermore, we will present multiple lines of evidence suggesting that telomeres can act as sensors of both intrinsic and extrinsic stress as well as recent data indicating that telomere–induced senescence may occur irrespectively of the length of telomeres.
Keywords: Telomeres, Senescence, Stress, Ageing, DNA damage
1. Cellular Senescence and Telomeres
Cellular senescence was first described by Hayflick and Moorhead as the progressive and irreversible loss of proliferative potential of human somatic cells (Hayflick and Moorhead, 1961). This phenomenon is characterized not only by a loss in replicative capacity, but also by a series of dramatic changes in cell morphology, gene expression, metabolism, epigenetics and others (van Deursen, 2014). It is a stable phenotype, with senescent cells being able to be kept in culture for several years following the initial arrest.