Fig. 2: Functional Mk-biased HSC expansion using the Microniche culture system in vitro and ex vivo.

Representative FACS profiles (a) and quantification (b) of phenotype-defined HSC and Mk subpopulations in long-term in vitro culture of UCB CD34⁺ cells. Percentage of the indicated cells relative to total live cells at weeks 0 to 6, and absolute cell counts at peak population density. Fresh n = 4 technical replicates; Control, week 2 and week 6 n = 5 biological replicates, week 4 n = 6 biological replicates; UM171, week 2 and week 6 n = 5 biological replicates, week 4 n = 7 biological replicates; Microniche, week 2 and week 4 n = 5 biological replicates, week 6 n = 3 biological replicates. All data represent means ± s.d.; comparisons with control by unpaired two-tailed Student’s t test. c–h Analysis of Mk reconstruction in LDA xenografts. c Flow cytometry gating for human Mk lineage in BM cells of recipient NOG mice. Representative FACS profiles of Mk reconstruction in BM mCD45⁻hCD45⁺hCD34⁺hCD38⁺ (d) or mCD45⁻hCD45⁻mCD41⁻mCD42d⁻mCD61⁻ (e) cells of NOG mice at 16 weeks post-transplantation. f The proportions of successfully reconstituted myeloid (My; mCD45⁻hCD45⁺hCD33⁺), lymphoid (Ly; mCD45⁻hCD45⁺hCD19⁺), and megakaryocytic (Mk; mCD45⁻hCD45⁻mCD41⁻mCD42d⁻mCD61⁻hCD41a⁺) lineages in hCD45⁺ engrafted mouse recipients. g The proportion of engrafted NOG mice with successful Mk lineage reconstruction based on the Mk population presence in BM mCD45⁻hCD45⁺hCD34⁺hCD38⁺ or mCD45⁻hCD45⁻mCD41⁻mCD42d⁻mCD61⁻ cell populations. h Mk-HSC frequency based on the mCD45⁻hCD45⁻mCD41⁻mCD42d⁻mCD61⁻hCD41a⁺ subpopulation 16 weeks post-transplantation. Fresh n = 43, Control n = 30, Microniche n = 36 biologically independent animals. Chi-square test. Solid lines indicate best-fit linear model and dashed lines confidence intervals. Box plots show the median (middle line) with the 25th and 75th percentiles (box).