Hematopoietic stem cells in the bone marrow are responsible for creating blood and immune cells, but their functionality declines with age. Research suggests that aging of the stem cell niche plays a crucial role in this decline. Scientists have identified specific signaling in mesenchymal cells that is relevant to the aging of hematopoietic stem cells. Studying hematopoietic stem cells at the single-cell level has revealed that despite being genetically identical middle-aged mice, their stem cells aged differently. The decline of growth factors like Kitl and Igf1 from mesenchymal stromal cells correlates with age-associated molecular changes in hematopoietic stem cells.
In a recent study, individual single cell transcriptomic profiles of hematopoietic and non-hematopoietic cells in mice provided insight into the aging of hematopoietic stem cells. The decline in signaling from mesenchymal stromal cells, particularly ADIPOQ, KITL, and IGF1, was found to have the greatest impact on middle-aged HSCs. Lower expression of Kitl and Igf1 in MSCs correlated with reduced lymphoid lineage commitment of HSCs and increased signatures of inactive HSCs. These findings highlight the importance of the decline in KITL and IGF-1 signaling in the aging hematopoietic stem cell niche.
