Fig. 5
HSCs exposed to an artificial in vitro niche functionalized with cell-cell interaction molecules slow down proliferation and retain in vivo reconstitution potential. a PEG microwell array functionalized with APC, JamC, Esam, or Ang1. Immunofluorescent images of JamC-functionalized microwells stained with anti-JamC antibody and fluorescently conjugated anti-rat antibody. b Percentage of cells undergoing no divisions over 120 h in non-functionalized microwells (control) or microwells functionalized with APC, Ang1, Esam or JamC. Graph indicates percentages of cells. Dead cells excluded. *p ≤ 0.05, **p ≤ 0.01 in Fisher’s exact test. c Cumulative histogram of time until first division for HSC cultured in non-functionalized microwells (control, black) or microwells functionalized with APC (blue), Ang1 (green), Esam (red) or JamC (purple). Number of single cells is for control n = 86, for Ang1 n = 162, for APC n = 165, for Esam n = 134, for JamC n = 143. d HSCs were cultured for 120 h in non-functionalized microwells (control) or microwells functionalized with JamC or Esam and the progeny of 100 cells was recovered and injected in lethally irradiated mice. Blood of recipient mice was analyzed at 4, 8, or 16 weeks. e Graph indicates percentage of donor-derived cells at 4 weeks, 8 weeks, or 16 weeks in mice engrafted with cells exposed to non-functionalized microwells (control) or microwells functionalized with JamC or Esam. Graph represents pooled data from two independent experiments. Gray lines indicate percentage of donor-derived cells for single mice of both experiments. Black line indicates mean for all animals. Number of recipients surviving at 16 weeks for both experiments is n = 18 for control, n = 17 for JamC, and n = 15 for Esam. *p ≤ 0.05, **p ≤ 0.01. Bars indicate significance at p ≤ 0.05 in non-parametric Mann–Whitney test. See also Supplementary Figs. 6–8
