The premature ageing ataxia telangiectasia (AT) and Werner syndromes (WS) are associated with accelerated cellular ageing. Young WS fibroblasts have an aged appearance and activated p38 MAP kinase, and treatment with the p38 inhibitor SB230580 extends their lifespan to within the normal range. SB203580 also extends the replicative lifespan of normal adult dermal fibroblasts, however, the effect is much reduced when compared to WS cells, suggesting that WS fibroblasts undergo a form of stress-induced premature senescence (SIPS).
The phenomenon that caloric restriction increases life span in a variety of species from yeast to mice has been the focus of much interest. Recent observations suggest that a protein important for heterochromatin formation, Sir2, is central for caloric restriction-induced longevity in lower organisms.
As the basis for the lifelong clock and as a primary cause of aging, a process of shortening of hypothetical perichromosomal DNA structures termed chronomeres is proposed in the CNS. The lifelong clock is regulated by the shortening of chronomere DNA in postmitotic neurons of the hypothalamus. Shortening of these DNA sequences occurs in humans on a monthly basis through a lunasensory system and is controlled by release of growth hormone discharged from the anterior pituitary directly into the hypothalamus via local blood vessels.
Werner and Bloom syndromes are human diseases characterized by premature age-related defects including elevated cancer incidence. Using a novel Saccharomyces cerevisiae model system for aging and cancer, we show that cells lacking the RecQ helicase SGS1 (WRN and BLM homologue) undergo premature age-related changes, including reduced life span under stress and calorie restriction (CR), G1 arrest defects, dedifferentiation, elevated recombination errors, and age-dependent increase in DNA mutations.
Caloric restriction (CR) is known to effectively elongate mammalian life-spans. The compound 2-deoxy-D-glucose (2DG), which is often used as an inhibitor of glucose utilization, is a mimetic agent of CR. In this study, we examined the changes of telomerase and Werner's syndrome RecQ (WRN) helicase after treatment with 2DG, because of the involvement of recQ helicase in the regulation of telomeres. Interestingly, 2DG treatment increased the expression of WRN protein in accordance with induction of its promoter activity and gene expression.
