The secret of their immortality
A colony of embryonic stem cells,
painted using antibodies to the protein OCT4.
Immortality of human embryonic stem cells due to enhanced proteostasis – process that regulates the quality of the produced proteins. This is the result of the study, a team of researchers from the University of Cologne.
Embryonic stem cells do not age and can divide indefinitely. The study showed, their viability is associated with the lack of accumulation of damaged proteins, such that cause Alzheimer's or Huntington's. Deliverance cells from protein the "garbage" part of proteostasis is carried out by the proteasome – multicomponent intracellular enzymes from the group of proteases.
Proteasome is responsible for these characteristics of embryonic stem cells self-renewal, pluripotency and differentiation.
An important role in the complex proteasomes belongs E3-ubiquitinate. This enzyme is to find and mark the damaged and incorrectly assembled proteins that must be split.
The researchers were removed from the DNA of stem cells, the gene responsible for the synthesis of E3-ubiquitinate, using the method of CRISPR and RNA. Surprisingly, no external changes have occurred – cells continued to function normally. This could be due to the interchangeability protein system proteostasis.
However, the global inhibition of proteasome disrupts a variety of processes that determine the functions of embryonic stem cells, including protein synthesis, maturation of ribosomal RNA, maintaining telomere length and stability of carbohydrate metabolism. Thus, these studies show that high proteasome activity in combination with other biological processes form the immortality of human embryonic stem cells.
The pathological accumulation of damaged proteins and leads to the development of neurodegenerative diseases. A deep study of the processes occurring in stem cells, including proteostasis, will help not only to understand the mechanisms of aging, but also to develop methods of prevention currently incurable neurodegenerative disorders.
Article I. Saez et al. Insights into the ubiquitin-proteasome system of human embryonic stem cells published in the journal Nature Scientific Reports.
Aminat adzhieva, the portal of "Eternal youth" http://vechnayamolodost.ru on materials of the University of Cologne: On the immortality of the stem cells.