Autophagy maintains metabolism and functional activity of a subset of aged hematopoietic stem cells [ERRBS]

Autophagy is critical for protecting HSCs from metabolic stress. Here, we used a genetic approach to inactivate autophagy in adult HSCs by deleting the Atg12 gene. We show that loss of autophagy causes accumulation of mitochondria and an oxidative phosphorylation (OXPHOS)-activated metabolic state, which drives accelerated myeloid differentiation likely through epigenetic deregulations rather than transcriptional changes, and impairs HSC self-renewal activity and regenerative potential. Quiescent HSCs HSCs (Lin-/c-Kit+/Sca-1+/Flk2-/CD150+/CD48-) were isolated from BL6 WT mice and activated HSCs were cultured 21 hours in cytokine+ media as described. DNA was extracted from -5 mice per group, and ERRBS was conducted as described in the methods. For cultured HSCs, HSCs were grown in StemPro34 medium (Invitrogen) supplemented with penicillin (50 U/ml)/streptomycin (50 μg/ml) and L-glutamine (2 mM), and with or without the following cytokines (±cyt): SCF (25 ng/ml), Flt3L (25 ng/ml), IL-11 (25 ng/ml), IL-3 (10 ng/ml), GM-CSF (10 ng/ml), Epo (4 U/ml) and Tpo (25 ng/ml) (Peprotech).