Toronto discovery in novel stem cell transplant

Toronto, ON – University Health Network researcher Dr John Dick and Hospital for Sick Children collaborator Dr Jayne Danska have discovered a gene with properties allowing successful engraftment of stem cells from human bone marrow into mice. Researchers hope further studies will lead to the development of a therapy so more children with blood diseases can receive bone marrow transplantation.

Drs Dick and Janska investigated the mouse strain in which transplanted human blood stem cells could engraft and develop that lead to the identification of the SIRPalpha gene – the one responsible for support of human blood cell engraftment and growth. The team also identified the type of cell that expresses SIRPalpha and is responsible for either destroying or supporting growth of human blood stem cells.

DNA sequencing of individuals from four different ethnic and racial populations was conducted and showed that 10 different types of this gene existed among just 37 individuals. Some of the specific variations that were found in humans line up with the positions of the gene that were found to be responsible for human stem cell support in the mouse transplant setting.

“Genes that control stem cells could also play a role in other blood disease processes like leukemia and anemia,” says Dr Dick. “So we will also investigate whether SIRPalpha plays a broader role in these human diseases.”

Scientists are hoping this gene discovery will lead to the development of a therapy that would mimic the effects of SIRPalpha and create conditions for a successful bone marrow transplant. In addition, the identification of this gene may help provide a genetic test that could be applied to blood stem cell donors and recipients to increase opportunities for successful transplants.

Findings were reported last week in Nature Immunology’s advanced online publication.