Sirtuins known as Sirt2 proteins are enzymes, NAD+-dependent deacetylases. Seven homologues of sirtuins (SIRT 1-7) were identified in mammals, which differ in location in cells, activity, function. They play an important role in metabolic processes, aging processes, growth and proliferation. Researchers have been working to find possibility of modulation of biological activity in treatment of metabolic diseases or age-related diseases.

Sirtuins have intrigued researchers who study ageing since they were first linked to longevity in yeast which is why they conformed a lot of experiments. Results of research suggest their ability to extend of lifespan of many organisms.

Sirtuins seem to have the same anti-aging effect as a drastic reduction in calories. For years researchers have known that lifespan can be extended in many kinds of creatures if the animal is fed a diet that contains about 30 percent fewer calories than usual. Scientists found that the lifespan extension doesn’t occur if the animal has been genetically altered to lack sirtuins, indicating these enzymes are crucial to this process.

Results published in Nature suggest that the overexpression of gene SIRT6 can lengthen lifespan in male mice by as much as 15.8%
SIRT6 is localized in nucleus, plays the role in process of damaged DNA repair.
In 2006 researchers published results of experiment which suggested that mice lacking SIRT6 seemed to age more quickly, were small, had a reduced ability to repair damaged DNA. Cohen and his colleagues decided to find out what would be effect higher level of the SIRT6 proteins than normal. Research showed that the excess protein didn’t affect longevity in female mice but the median lifespan of male mice rose by 14.5% in one line of their transgenic mice and 9.9% in another. Maximum lifespan rose by 15.8% in the first line of mice, and 13.1% in the second, although the latter increase was not statistically significant. Richard Miller, who studies ageing at the University of Michigan in Ann Arbor pointed out that the strain of mice used in the study was particularly prone to tumors, especially in males so it is possible that the longer lifespan could be the result of an anti-cancer effect of SIRT6.
Why does SIRT6 affect males and females differently? We haven’t known the answer this question yet but in the strain of mice used, females live about 15% longer than males.

Sirtuins play an important role in metabolic processes, apoptosis, damaged DNA repair. It can suggest their ability to extend lifespan. Researchers have been working to find new possibilities of using sirtuins but there are a lot of unanswered questions.

Written by: Paulina Dzięga

Source:
1. http://www.nature.com/news/sirtuin-protein-linked-to-longevity-in-mammals-1.10074
2. http://pml.strefa.pl/ePUBLI/164/14.pdf
3. http://www.sirtuins.com/
4. http://onlinelibrary.wiley.com/doi/10.1002/emmm.201201452/full
5. http://en.wikipedia.org/wiki/Sirtuin


Want to know more? Watch on medtube.net: ”Mitosis”