Decreased non-neurogenic acetylcholine in bone marrow triggers age-related defective stem/progenitor cell homing.

Age-related decline in the ability of bone marrow (BM) to recruit transplanted hematopoietic stem and progenitor cells (HSPCs) limits the potential of HSPC-based medicine. Using in vivo imaging and manipulation combined with integrative metabolomic analyses, we show that, with aging, degradation of non-neurogenic acetylcholine disrupts the local Chrm5-eNOS-nitric oxide signaling, reducing arterial dilation and decreasing both BM blood flow and sinusoidal wall shear stress. Consequently, aging BM microenvironment impairs transendothelial migration of transplanted HSPCs, and their BM homing efficiency is reduced, mediated by decreased activation of Piezo1. Notably, pharmacological activation of Piezo1 improves HSPC homing efficiency and post-transplant survival of aged recipients. These findings suggest that age-related dysregulation of local arteries leads to impaired HSPC homing to BM by decreasing shear stress. Modulation of these mechanisms may improve the efficacy and safety of clinical transplantation in elderly patients.