Progenitor cells forming adipose tissue have been identified

Scientists at Howard Hughes University and Rockefeller University, working under the guidance of Professor Jeffrey Friedman, identified adipocyte progenitor cells, the presence of which explains how the number of fat cells can increase and lead to the development of obesity. This discovery will help specialists to understand how adipocytes (fat cells) are involved in the development of pathologies such as diabetes and cardiovascular diseases.

The causes of obesity – one of the most important public health problems – include an increase in the mass and number of white fat cells. Since these cells are postmitotic and are not capable of division, scientists have suggested that a population of progenitor cells capable of forming new adipocytes should exist in adipose tissue. However, it has not been possible to identify these cells so far.

Using the method of flow cytometry, the authors identified two populations of potential progenitor cells. To test the ability of these cells to give rise to adipocytes, the researchers injected them into the areas of normal fat deposition to genetically modified mice that do not have their own white fat and are a model of the human disease lipodystrophy, which often leads to the development of diabetes.

One of the tested populations, whose cells express the CD24 cell surface marker, formed fat deposits in experimental animals. This population usually makes up no more than 0.08% of all non-fat cells contained in normal adipose tissue.

The new imaging method made it possible to observe the transformation of CD24 expressing cells into fat cells in a living organism. To do this, the authors used another line of animals – the so-called leptin-luciferase mice, in whose body the bioluminescent protein luciferase is expressed under the control of the promoter of the gene producing leptin hormone synthesized in mature fat cells. In such animals, the luciferase gene is activated only in fat cells, which makes it possible to observe the transformation of progenitor cells into mature adipocytes in the body of living animals (in pictures taken within three months, "mature" adipocytes glow red).

The authors also found that the introduction of adipose tissue-forming cells to fat-free mice cures their diabetes and that fat cells secrete adipocyte-specific signaling proteins. These results confirm the fact that the cells formed in the body of such animals are fully functioning fat cells.

According to the authors, this discovery improves our understanding of the biology of adipose tissue and provides opportunities to study cells in a living organism, as well as to identify molecular factors that control the formation of adipose tissue. Thanks to the results obtained, specialists were able to study the mechanisms of regulation of the processes of growth and differentiation of identified cells in obesity and the possible involvement of molecular factors regulating the functioning of adipose tissue in the development of other pathologies associated with obesity and metabolic syndrome, such as diabetes and cardiovascular diseases.

Article by Rodeheffer et al. "Identification of White Adipocyte Progenitor Cells In Vivo" is published in the October issue of the journal Cell.

Portal "Eternal youth" http://vechnayamolodost.ru / based on ScienceDaily – Obesity Clue: Newly Identified Cells Make Fat

07.10.2008