GSE209742
Genotoxic aldehyde stress prematurely ages hematopoietic stem cells in a p53-driven manner
Aged hematopoietic stem cells (HSC) display diminished self-renewal and a myeloid differentiation bias. However, the physiological drivers and molecular processes that underpin this fundamental switch are not understood. HSCs produce formaldehyde and are protected from this metabolite by two tiers of protection: the detoxification enzymes ALDH2 and ADH5 and the Fanconi anemia (FA) DNA repair pathway. Using single cell RNA sequencing, we find that the HSC and progenitor cells in young Aldh2-/- Fancd2-/- mice harbor a transcriptomic signature equivalent to aged wild-type HSCs, along with increased epigenetic age, telomere attrition and myeloid-biased progenitors. In addition, the p53 response is vigorously activated in Aldh2-/- Fancd2-/- HSCs, whilst p53 deletion rescued this aged transcriptomic signature and telomere attrition. Transplantation of single Aldh2-/- Fancd2-/- HSCs also reveals a predominantly myeloid output, which is reversed upon p53 deletion. To further define the origins of the myeloid differentiation bias, a GFP genetic reporter which detects Vwf+ myeloid primed HSCs was crossed into Aldh2-/- Fancd2-/- mice, revealing a striking enrichment of these lineage-biased Vwf+ HSCs. These results indicate that metabolism derived formaldehyde causes endogenous DNA damage which stimulates the p53 response in HSCs, which then accelerates their aging, resulting in a myeloid lineage biased output. Overall design: Lin-Sca1+cKit+ cells from WT, Aldh2 knock-outs, Fancd2 knock-outs, p53 knock-outs, Aldh2 & Fancd2 double knock-outs, Aldh2 & Fancd2 & p53 triple knock-outs