Reviewing Recent Work on the Mechanisms of Cellular Senescence

Impressive results have been produced in mice via clearance of senescent cells: rejuvenation, extension of life, and reversal of numerous different age-related conditions. This has provoked an increasing number of research groups to focus on the mechanisms of cellular senescence, in search of novel ways to identify and destroy these cells, or to suppress the senescence-associated secretory phenotype (SASP) that they produce. The secreted signal molecules of the SASP alter surrounding cell behavior and rouse the immune system to chronic inflammation. This is the means by which the comparatively small number of lingering senescent cells present in late life can produce such a sweeping disruption of tissue function and health. One of the key stumbling blocks in the field of senescence is the lack of a single, universal, robust, biomarker that allows identification of senescent cells with high sensitivity and specificity and is capable of differentiating them from terminally differentiated, quiescent, and other non-dividing cells. Growth arrest is a key feature which can be readily demonstrated in vitro using assays that measure DNA synthesis. However, DNA synthesis measurement is not totally specific since DNA repair may still be active. Measuring the expression levels of p16INK4A and p21WAF1/CIP1 are key to detecting cell cycle arrest but are not expressed persistently particularly p21WAF1/CIP1 by senescent cells. Accumulation of high levels of p16INK4A is required to ...
Source: Fight Aging! - Category: Research Authors: Tags: Daily News Source Type: blogs