Deficiency of Antioxidative Paraoxonase 2 (Pon2) Leads to Increased Number of Phenotypic LT-HSCs and Disturbed Erythropoiesis

Figure 4

Effects of PON2-inactivation on erythropoiesis. (a–c) Analysis of 3 different stages of erythrocyte development in the bone marrow of WT and Pon2^-/- mice. Following the isolation of the bone marrow, cells were stained with the antibodies CD71 and Ter119 and analyzed by flow cytometry. The graphs show the percentage of (a) proerythroblasts (CD71 high/Ter119 mid), (b) basophilic erythroblasts (CD71 high/Ter119 high), and (c) polychromatic erythroblasts (CD71 mid/Ter119 mid). Dot plot diagram. Dot each individual animal; . , ; -test. (d) Lifespan of erythrocytes in young PON2^-/- mice. Erythrocyte degradation and regeneration were analyzed using in vivo biotinylation. Young Pon2-deficient and WT mice were injected with sulfo-NHS-biotin (intravenous), and small blood samples were taken every few days over a total of 34 days. Afterwards, isolated blood cells were stained with fluorescence-conjugated streptavidin as well as the erythrocyte specific marker Ter119 and analyzed using flow cytometry to determine the number of biotinylated erythrocytes. Results are shown as percentage of biotinylated erythrocytes at day 1, immediately after biotin injection; , . A nonlinear regression was calculated (R2 erythrocytes = 0.90); vertical dashed lines represent the half-life () of the respective cells from WT (light gray) or Pon2^-/- (black) mice. ; n.s.: not significant; -test. (e, f) Percentage of red blood cells in the blood of Pon2^-/- and WT mice during the induction of hemolytic anemia by phenylhydrazine. Pon2-deficient and wild-type mice were i.p. injected with either phenylhydrazine or PBS (control group) on days 1 and 3. On day 1 (before the start of treatment) and on days 3 and 5, a small amount of blood was taken from the test animals by scratching the Vena caudalis mediana in order to analyze the number of erythrocytes. The percentage of erythrocytes in the blood (e) of the phenylhydrazine group and (f) of the control group is shown in comparison to the mean value of the respective starting amount. ; . ; ns = not significant; -test.

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