Will fat cells be able to prolong life and protect against stress?
As part of an ongoing study on the biology of aging, which is the main risk factor for type 2 diabetes and other serious diseases, researchers at the Joslin Diabetes Research Center, working under the guidance of Professor Ronald Kahn, identified a new factor that plays an important role in the aging process and resistance to stress – processing microRNAs ("refinement" after their transcription – synthesis at the DNA site) in adipose tissue cells. The data obtained can form the basis for the development of therapies aimed at increasing resistance to stress, increasing life expectancy and improving metabolism.
In recent years, experts have become convinced that adipose tissue cells – adipocytes – are not only storage of lipids. They synthesize and secrete a number of compounds that actively affect metabolism and systemic inflammatory processes. Earlier studies have shown that reducing the mass of adipose tissue while following a low-calorie diet, surgically or using genetic approaches can contribute to longevity and increase the resistance to stress of representatives of different species, ranging from yeast to primates. However, very little is known about the mechanisms underlying this phenomenon. The authors of the study devoted their work to studying one of the types of molecular processes – changes in the processing of microRNAs and proteins necessary to trigger these changes – affected by the aging process and restored by a low-calorie diet.
When conducting studies on human cells, mice and C.elegans roundworms, scientists have demonstrated that the levels of many microRNAs in adipose tissue cells of representatives of all three species decrease as they age. The reason for this is a decrease in the concentration of the important enzyme Dicer, which ensures the conversion of microRNA precursors into mature microRNAs.
A low-calorie diet prevents a decrease in Dicer levels and, at least in mice, restores the levels of microRNA in adipocytes to those characteristic of young age. On the contrary, exposure to stressors associated with aging and metabolic diseases, including toxins, reduces the levels of this enzyme. Genetically modified mice and roundworms with low Dicer expression are characterized by increased sensitivity to stress, which is a sign of premature aging. At the same time, roundworms with increased expression of this enzyme in the intestine (the equivalent of adipose tissue in mammals) live longer than wild-type individuals and demonstrate increased resistance to stress.
In general, the research results indicate that the processing of microRNAs in adipose tissue plays an important role in longevity and the body's ability to respond to stresses associated with aging and environmental exposure. The authors believe that the data they have obtained will help in the search for methods to optimize this process to protect the body from stress and prevent the development of age-related and stress-related diseases. Currently, they are working on genetic methods for regulating the level of the Dicer enzyme in the adipose tissue of mice in order to create mouse models that are resistant to stress to varying degrees.
The article by Rozalyn M. Anderson A Role for Dicer in Aging and Stress Survival is published in the journal Cell Metabolism.
Evgeniya Ryabtseva
Portal "Eternal youth" http://vechnayamolodost.ru based on the materials of Cold Spring Harbor Laboratory:
Joslin Scientists Identify Molecular Process in Fat Cells That Influences Stress and Longevity.
28.09.2012