Figure 3.

Proposed model on the effects of low-LET ¹H and high-LET ⁵⁶Fe radiation on hematopoietic progenitor cells in the bone marrow niche. There is a significant decrease in MPP population numbers upon exposure to particle radiation. The majority of surviving cells experience DNA damage (depicted in blue) and oxidative stress (depicted by ROS), which could result in DNA mutations (depicted in red). While some MPPs continue to differentiate into blood cells, the remaining cells are “reprogrammed” to maintain pluripotency. As a result, even months post-IR, these “reprogrammed” MPPs [containing IR-induced mutations (depicted in red)] persist and give rise to differentiated blood cells, thereby propagating mutations to subsequent lineages, which may cause hematologic disorders, such as cancer. Blue cells represent multipotent progenitor cells and green cells represent differentiated blood cells.