Stem cell factor acts locally in the bone marrow to promote stem and progenitor cell maintenance

Stem cell factor (SCF) produced by certain cells within the bone marrow is crucial for maintaining hematopoietic stem and progenitor cells, according to recent research. LepR+ mesenchymal stromal cells and endothelial cells are found to secrete SCF, with higher concentrations observed in the former compared to the latter. However, it was discovered that endothelial cells outside the bone marrow are responsible for circulating SCF, leading to the question of whether the SCF promoting stem and progenitor cell maintenance originates inside or outside the bone marrow.

To answer this question, researchers conducted experiments involving the deletion of SCF in different types of endothelial cells. They discovered that removing SCF from spleen and liver endothelial cells led to a decrease in SCF levels in the blood, but did not impact the number of stem or progenitor cells in the bone marrow. Similarly, when SCF was deleted from mesenchymal cells in the long bones of mice, it resulted in a depletion of stem and progenitor cells in the long bones, but not in the vertebrae.

This finding suggests that SCF acts locally within the bones where it is produced to promote the maintenance of stem and progenitor cells.