Figure 2.

Effects of inflammation and aging on the HSC niche. (A) Multiple bone marrow niche cells such as mesenchymal stromal cells (MSCs) and specifically CXCL12-abundant reticular (CAR) cells, endothelial cells, but also hematopoietic cells such as megakaryocytes, T-cells and macrophages affect HSC quiescence through diverse molecular mechanisms, including cytokine secretion as depicted. (B) During aging, HSC accumulation but with increased distance from arterioles, sinusoids and megakaryocytes is accompanied by inflammatory signaling and cytokine secretion from various bone marrow populations including CAR cells and senescent fibroblasts (SASP: Senescence-associated secretory phenotype). Aged MSCs turn primarily into adipocytes and adrenergic signaling is disturbed. Created with BioRender.com, accessed on 3 June 2021.