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T. Wang et al.
Nupr1-/-: 74% vs. 86%) and less irradiation-induced apoptot- ic Nupr1-/- HSC compared with WT HSC (Online Supplementary Figure S4C). The proportion of cycling cells (G1-S-G2-M proliferative phases) in the residual Nupr1-/- HSC was still significantly higher (P<0.001) than the WT
HSC 24 h after irradiation (WT vs. Nupr1-/-: 29% vs. 48%) (Online Supplementary Figure S4D). Thus, Nupr1-/- HSC were susceptible to irradiation-induced damage, but the surviv- ing HSC proliferated, resulting in a fast recover of the HSC pool.
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Figure 2. Nupr1-/- hematopoietic stem cells show a repopulating advantage in competitive transplantation experiments. (A) Schematic diagram of the competitive transplantation assay. Bone marrow nucleated cells (BMNC; 2.5x105) from Nupr1-/- (CD45.2) or littermate control (Vav-cre+, CD45.2) mice were mixed with equivalent wild-type (WT) (CD45.1) counterparts and injected into individual lethally irradiated recipients (CD45.1). Four months later, the recipients were sacrificed and 1x106 BMNC from primary transplanted recipients were transplanted into lethally irradiated secondary recipients. (B) Kinetic analysis of donor chimerism (CD45.2+) in peripheral blood (PB). Data were analyzed by two-way analysis of variance (ANOVA) and are represented as mean ± standard deviation (SD) (control group: n=5 mice; Nupr1-/- group: n=6 mice). *P<0.05, **P<0.01. (C) Kinetic analysis of donor-derived lineage chimerism in PB, including myeloid cells (CD11b+) (left), B lymphocytes (CD19+) (middle), and T lymphocytes (CD90.2+) (right). Data were analyzed using a paired Student t-test (two-tailed) and two-way ANOVA and are represented as mean ± SD (control group: n=5 mice, Nupr1-/- group: n=6 mice). *P<0.05. (D) Flow cytometry analysis of the hematopoietic stem cell (HSC) compartment in primary recip- ients 4 months after transplantation. Representative plots from one recipient mouse in each group are shown. (E) Cell number and percentage of donor-derived HSC in primary recipients 4 months after competitive transplantation. Data were analyzed using a Student t-test and are represented as mean ± SD (n=5) **P<0.01.
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haematologica | 2022; 107(1)