Percent colony formation in young and old WT HSCs cultured for 32h ± BafA and methylpyruvate (M-Pyr) (n = 3). Colonies were counted at day 10 and normalized to -BafA conditions. Data are means ± s.d. *P ≤ 0.05, **P ≤ 0.01, ***P ≤ 0.001. 