Cold Spring Harbor, N.Y. Hematopoietic stem cells (HSCs) have two unique abilities that are prized by medical researchers: to self-renew and to develop into any kind of blood cell, which enables them to replenish the entire blood and immune system. Scientists have traced these qualities to a distinct locale or niche within the bone marrow that HSCs home in on, but the identity and function of the niche-forming constituents have not been clearly defined.
Now, the precise source of HSC maintenance and regulation within the bone marrow has been discovered by Cold Spring Harbor Laboratory (CSHL) researchers and members of a multi-institutional team. In a study to be published in Nature on August 12th, the collaborators report that the HSCs retain their unique features in response to signals from another stem cell population, the mesenchymal stem cells (MSCs), which create a supportive bone marrow niche for the HSCs.
"This is the first demonstration that one type of stem cell can regulate another type of stem cells," says CSHL scientist Grigori Enikolopov, Ph.D. "Having a detailed understanding of how HSCs are maintained within the niche microenvironment offers new opportunities to better exploit these cells for therapeutic use."
The path to this discovery originates from Enikolopov's efforts to develop reliable ways of distinguishing stem cells from other cell types. Previously, his group found that various types of stem cells express a protein called nestin. In recent years, they have detected and analyzed stem cell populations located in niches throughout the body using mice genetically engineered such that nestin-expressing cells also produce a fluorescent marker, making it possible to visually track these cells.
One location where the CSHL researchers found these nestin-expressing cells was the bone marrow, but these cells proved to not be HSCs. To find the identity and function of these mystery cells, they teamed
|Contact: Hema Bashyam|
Cold Spring Harbor Laboratory