Stem cell memories may hold answer to their reproduction, study finds

Hematopoietic stem cells (HSCs) are stem cells that reside in bone marrow and are responsible for maintaining the continuous production of blood throughout life. HSCs have been used clinically for decades to treat various blood-borne illnesses ranging from leukemia to severe combined immunodeficiency syndrome. However, a major barrier to treatment is the limited availability of stem cells. Clinicians and researchers have worked to expand stem cell numbers, but have been largely unsuccessful at facilitating reproduction of these cells. This research provides clues as to why these efforts have not succeeded -- because these cells count and retain a memory of their divisions, which control their potential for further reproduction.

According to the researchers, the study found that slow cycling cells contained all of the long-term HSC activity among the aging cells in the bone marrow. The data collected further shows that age-related changes to the HSCs, including HSC expansion, are dependent on the cells knowing how many times they have divided.

"What this essentially means is that these important stem cells remember how many times they have divided, and those memories control how they will self-renew in the future," said Kateri Moore, DVM, Associate Professor of Cell, Developmental and Regenerative Biology at the Icahn School of Medicine at Mount Sinai. "This knowledge may be able to help us find the key to expanding the numbers of these cells for therapeutic and research use."

Both Dr. Moore and the lead author Jeffrey Bernitz, a PhD candidate at the Icahn School of Medicine at Mount Sinai, hope that the results of this study will provide additional clues that will help us achieve stem cell expansion in the future.