A research team at Albert Einstein College of Medicine has made a discovery that could improve the effectiveness of stem-cell transplants, which are often used to treat cancer, blood disorders, and autoimmune diseases.
The findings, made in mice, were published today in Science. Dr. Ulrich Steidl, who led the research, believes this could enhance the success of stem-cell transplants and broaden their use.
Stem-cell transplants treat diseases where a person’s blood-forming stem cells (HSCs) are either cancerous or too few in number, such as leukemia or bone marrow failure. The treatment involves giving healthy HSCs from donors to patients. Donors are given a drug to make HSCs leave the bone marrow and enter the blood for collection.
However, these drugs often don’t release enough HSCs for a successful transplant. Dr. Will from Albert Einstein College of Medicine explained that their research helps better understand how HSCs move from the bone marrow to the blood, offering a new way to improve this process for transplants.
The researchers found that specific proteins on the surface of blood-forming stem cells (HSCs) might affect their ability to leave the bone marrow. In mice, they noticed that HSCs with specific surface proteins, usually found on immune cells called macrophages, tended to stay in the bone marrow. Those without these proteins were likelier to leave when given drugs to boost mobilization.
The team discovered that HSCs could take membrane parts from macrophages through trogocytosis. HSCs with high levels of the protein c-Kit were better at this, causing them to stay in the bone marrow. The study suggests that blocking c-Kit could prevent trogocytosis, helping more HSCs leave the bone marrow for transplantation.
“Trogocytosis is known to help regulate immune responses, but this is the first time we’ve seen stem cells use it,” said Dr. Gao from the University of Wisconsin-Madison.
The researchers are still trying to understand how blood-forming stem cells (HSCs) control this process. They plan to continue studying trogocytosis in HSCs to see if it has other roles, such as in blood regeneration, removing defective stem cells, or in blood cancers.
Journal reference:
- Xin Gao, Randall S. Carpenter et al., Regulation of the hematopoietic stem cell pool by C-Kit–associated trogocytosis. Science. DOI: 10.1126/science.adp2065.