Extended Data Fig. 10: Summary cartoon scheme and gating strategies.

a, Cartoon scheme depicting alterations of the aged niches. Aged HSCs compared to young are located more distant to the endosteum, to megakaryocytes, to arterioles and to periarteriolar Nes-GFP^high cells but not to Nes-GFP^low cells and sinusoids. With aging megakaryocytes are increased in number. Endosteal endothelial cells and endosteal/periarteriolar Nes-GFP^high cells are dramatically reduced. The anatomy and morphology of arteries and arterioles in the aged BM is massively changed. The morphology, anatomy and numbers of central BM vessels, which are comprised mainly of sinusoids, and perisinusoidal Nes-GFP^low cells are preserved upon aging. LR-HSCs, which represent in aged mice the population of aged HSCs with the highest regenerative potential, cell polarity and active Notch signalling, were exclusively found as individual stem cells at sinusoidal niches, whereas aged nLR-HSCs are more distant to sinusoids and to other described BM niche cells and show clustering phenotype. Importantly, Jag2 plays a functional role in the maintenance of proximity and quiescence of HSCs at sinusoids. b, Representative gating strategy for Nes-GFP ^high and ^low BM cells; c, Gating strategy for megakaryocytes; d, Gating strategy for endothelial cells; e, Gating strategy for PB cells. Representative gating strategy example of B220, CD3, Mac-1 and Gr-1 staining profile of white blood cells from an aged C57Bl6 mouse (more than 100-week-old).