26 January 2015

Temporary lengthening of telomeres slows down cell aging

Researchers at Stanford University Medical Center, working under the guidance of Professor Helen Blau, managed to increase the telomere length of cultured human skin cells and muscle cells by 1,000 nucleotides. This significantly increased the number of cell division cycles.

Telomeres are the end sections of chromosomes that perform a protective function. The telomere length of a young person is approximately 8,000-10,000 nucleotides. With each cell division, the length of its telomeres decreases and when its critical length is reached, the cell loses its ability to divide. In laboratory conditions, this limits the life of cell cultures and makes it difficult to conduct research.

In the search for a method of prolonging the life of cultured cells, the authors achieved a very impressive result by exposing the cell culture to modified information RNA (mRNA) containing the sequence of the gene encoding TERT, the active component of the telomerase enzyme. This enzyme, which restores telomere length, is normally expressed by stem and germ cells. However, most cells of other types express only low levels of this enzyme or do not have it at all.

Schematic representation of the main subunits of human telomerase (diagram from the website openi.nlm.nih.gov )

The new method has a significant advantage over other potential approaches, consisting in the reversibility of the action provided. The mRNA created by the authors is designed in a special way that allows suppressing the reaction of cells to exposure. However, it decays within about 48 hours. After that, the elongated telomeres begin to progressively shorten again with each cell division. Thus, there is a postponement of the physiological aging of the cell, which does not acquire immortality and, accordingly, does not become potentially dangerous from the point of view of malignancy.

The researchers demonstrated that three-fold introduction of modified mRNA into the cell culture within a few days makes it possible to increase the telomere length of human skin cells and muscle cells by 1,000 nucleotides, that is, by more than 10%. As a result, the number of divisions that skin cells are capable of under culture conditions increases by about 28 times, while the number of divisions of muscle cells increases by 3.4 times.

The authors believe that the approach they have developed can be used in the treatment of age-related diseases and severe hereditary pathologies associated with rapid shortening of telomeres, such as Duchenne myodystrophy. They are currently testing the technique on other cell types.

Article by J. Ramunas et al. Transient delivery of modified mRNA encoding TERT rapidly extends telomeres in human cells is published in The FASEB Journal.

Evgeniya Ryabtseva
Portal "Eternal youth" http://vechnayamolodost.ru based on the materials of Stanford University Medical Center:
Telomere extension turns back aging clock in cultured human cells, study finds.


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