It’s well-known that our bodies change as we age, with one of the most noticeable changes being the accumulation of belly fat. But why does this happen? Scientists at the City of Hope Research Center have made a discovery that may provide a deeper understanding of this phenomenon. They have identified a new type of stem cell that plays a crucial role in the formation of new fat cells, potentially paving the way for new strategies to improve health as we get older.
Discovery of New Stem Cells
The study began by examining white adipose tissue, the main fat storage tissue in the body. While it was known that existing fat cells enlarge with age, researchers suspected another process contributing to fat accumulation around the abdomen: the creation of entirely new fat cells.
Scientists studied specific stem cells known as adipocyte progenitor cells (APCs), which act as precursors that can mature into full-fledged fat cells. Experiments showed that when these cells were transferred from older mice to younger ones, they produced a large number of new fat cells, indicating that the ability to produce fat was linked to the stem cells themselves, not the age of the recipient animal.
Molecular Processes Behind Fat Formation
To test their hypothesis further, researchers used single-cell RNA sequencing to examine gene activity in individual cells. The results showed that adipocyte progenitor cells were relatively inactive in young mice but became highly active in middle-aged mice, leading to the production of a significant number of new fat cells.
Researchers also discovered that some of these cells transformed into a new type of stem cell called age-associated committed preadipocytes (CP-As), which proved effective in producing new fat cells, explaining the increase in fat in older mice.
The Impact of LIFR Signaling on Fat Formation
The researchers found that a signaling pathway known as the leukemia inhibitory factor receptor (LIFR) plays a key role in promoting the proliferation and development of CP-As into fat cells. While young mice do not rely on this signal to produce fat, older mice depend on it significantly.
Similarities with Humans
To ensure the findings could apply to humans, the team analyzed tissue samples from people of various ages. They found cells similar to those discovered in mice, which were present in greater numbers in the tissues of middle-aged individuals, suggesting that a similar biological process might occur in humans as well.
Conclusion
The discovery of age-associated committed preadipocytes offers a promising target for future treatments to combat age-related obesity. While this field requires further research, understanding the role of these cells in metabolic disorders and how they emerge could lead to new medical solutions for enhancing health and longevity.