Figure 3.

Aging functionally compromises HSCs and erodes the lineage relationships between BM compartments during native hematopoiesis. (A) Single HSCs from 3 independent young or aged mice were individually plated in 96-well plates in media that supports HSC expansion (i; n = 44-67 clones analyzed per mouse) or differentiation media (ii; n = 27-41 clones were analyzed per mouse). (i) Division kinetics for each well were tracked, percentages of the cumulative number of divisions are shown. (ii) Percentages of clones that generate 1, 2, 3, or 4 myeloid lineages (see supplemental Figure 3A). Averages are shown; error bars represent standard deviation (#P < .1). (B) Distribution of Confetti colors in PB and BM in young (age 2 months) and old (age 26 months) mice. Three representative examples are shown for each mouse strain at each time point. (C) Heatmaps summarize the correlation of Confetti color distribution between different hematopoietic compartments in young (i; age 2 months) and old (ii; age 26 months) mice. Heatmaps depict the Pearson correlation coefficient between 2 cell compartments. At 2 months old: Conf-E2a^Cre (n = 14), Conf-VE^Cre(n = 13), Conf-Flk1^Cre (n = 7), and Conf-Vav1^Cre (n = 11). At 26 months old: Conf-E2a^Cre (n = 10), Conf-VE^Cre(n = 5), Conf-Flk1^Cre(n = 6), and Conf-Vav1^Cre (n = 9). (iii) Correlation values of BM compartments relative to HSCs at 2 and 26 months of age. Paired Student t test of correlation coefficient of cells vs HSCs indicate that the correlations are significantly reduced with age (P = .03) (see also supplemental Figure 3B). Source data are provided in supplemental Table 1.