A research team at the Albert Einstein College of Medicine has made a discovery that could improve the effectiveness of stem cell transplants, which are commonly used to treat cancer, blood disorders and autoimmune diseases.
The results obtained on mice were published today in ScienceDr. Ulrich Steidl, who led the research, believes this could increase the success of stem cell transplants and expand their application.
Stem cell transplants are used to treat diseases in which a person’s blood-forming stem cells (HSCs) are either cancerous or too few, such as leukemia or bone marrow failure. The treatment involves transferring healthy HSCs from donors to patients. Donors are given a drug that causes the HSCs to leave the bone marrow and enter the blood, where they can be collected.
However, these drugs often do not release enough HSCs for a successful transplant. Dr. Will, of the Albert Einstein College of Medicine, said 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 certain proteins on the surface of blood-forming stem cells (HSCs) could affect their ability to leave the bone marrow. In mice, they found that HSCs with certain surface proteins normally found on immune cells called macrophages tended to stay in the bone marrow. HSCs without these proteins were more likely to leave the bone marrow when given drugs to mobilize them.
The team discovered that HSCs can take up parts of macrophages’ membranes through trogocytosis. HSCs with high levels of the protein c-Kit were better at doing this, causing them to stay in the bone marrow. The study suggests that blocking c-Kit could prevent trogocytosis and help more HSCs leave the bone marrow for transplantation.
“Trogocytosis is known to help regulate immune responses, but this is the first time we have seen stem cells use this ability,” said Dr. Gao of the University of Wisconsin-Madison.
Researchers are still trying to understand how hematopoietic stem cells (HSCs) control this process. They plan to further study trogocytosis in HSCs to find out if it has other functions, such as blood regeneration, removal of defective stem cells or blood cancer.
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.
