![MK-specific PDK1 deficiency results in macrothrombocytopenia and a reduced platelet lifespan. (A) Arithmetic means ± standard error of the mean (SEM; n = 6, unpaired 2-tailed Student t test) of Pdk1 transcript levels in platelets and kidneys from Pdk1fl/fl and Pdk1−/− mice. Representative immunoblot of PDK1 protein levels in MKs from Pdk1fl/fl and Pdk1−/− mice (n = 5). mRNA, messenger RNA. (B) Arithmetic means ± SEM of platelet count and mean platelet volume of Pdk1fl/fl and Pdk1−/− mice aged 8 weeks (n = 13), 12 weeks (n = 22), and 18 weeks (n = 10). (C) Arithmetic means ± SEM (n = 12) of mean forward scatter (FSC) signal of Pdk1fl/fl and Pdk1−/− platelets. (D) Arithmetic means ± SEM (n = 8, unpaired 2-tailed Student t test) of relative spleen weight in Pdk1fl/fl and Pdk1−/− mice. (E) TPO levels of Pdk1fl/fl and Pdk1−/− mice. Arithmetic means ± SEM (n = 6, unpaired 2-tailed Student t test) are shown. TPO receptor/c-Mpl protein level in Pdk1fl/fl and Pdk1−/− MKs. Actin was used as loading control. Arithmetic means ± SEM (n = 5, unpaired 2-tailed Student t test) are shown. (F) Platelet counts of Pdk1fl/fl and Pdk1−/− mice before and 4 days after treatment with TPO (2 µg per animal per day). Arithmetic means ± SEM (n = 8, 2-way analysis of variance [ANOVA] with Bonferroni correction for multiple comparisons) are shown. (G) Endogenous survival of Pdk1fl/fl and Pdk1−/− platelets measured by determination of percent fluorescently labeled platelets in vivo at indicated time points after injection of DyLight 488 α-glycoprotein IX (GPIX) (n = 6, unpaired 2-tailed Student t test). (H) Platelet depletion in Pdk1fl/fl and Pdk1−/− mice was induced by IV injection of rat anti-GPIbα antibody (Emfret Analytics). Peripheral platelet counts were determined over a time course of 7 days by flow cytometry. The rate of platelet count recovery as compared with the respective initial platelet count is depicted (n = 4, unpaired 2-tailed Student t test). *P < .05 and **P < .01 as well as ##P < .01 indicate statistically significant differences.](https://ash.silverchair-cdn.com/ash/content_public/journal/blood/134/21/10.1182_blood.2019000185/7/bloodbld2019000185f1.png?Expires=1724941489&Signature=2vBMCFwzebyoE~JNd0JH~FsYzdfHRAQY21tOoNMxrJe1iDKGSxxkF9wlUBp~1TsdrXLr7yhHCGsTtwREl47Q677y~2B9qezqrtjOyqVwOdXX1yV7wFf6peHonzygO8I0uQlCIGarlj-rywTLrOdQIAmCQzbcQMcwXqkH6m7MODgONW8rEGzO5qF9VYUaUekxaPEEbPFbH2SDuApFX5lDX~f~y-1Td6evoMQR8TgcOJk8~Mklu4Z5mFLMAiCsVqXZ5V4LQZ11SE-UIWT0dtoZKITx9oKKNQh9QyPE4nu37mHlqevHitz6HhKM~QsSbWkhkOrA-hEZp5zdl34fJUfFcA__&Key-Pair-Id=APKAIE5G5CRDK6RD3PGA)
MK-specific PDK1 deficiency results in macrothrombocytopenia and a reduced platelet lifespan. (A) Arithmetic means ± standard error of the mean (SEM; n = 6, unpaired 2-tailed Student t test) of Pdk1 transcript levels in platelets and kidneys from Pdk1fl/fl and Pdk1−/− mice. Representative immunoblot of PDK1 protein levels in MKs from Pdk1fl/fl and Pdk1−/− mice (n = 5). mRNA, messenger RNA. (B) Arithmetic means ± SEM of platelet count and mean platelet volume of Pdk1fl/fl and Pdk1−/− mice aged 8 weeks (n = 13), 12 weeks (n = 22), and 18 weeks (n = 10). (C) Arithmetic means ± SEM (n = 12) of mean forward scatter (FSC) signal of Pdk1fl/fl and Pdk1−/− platelets. (D) Arithmetic means ± SEM (n = 8, unpaired 2-tailed Student t test) of relative spleen weight in Pdk1fl/fl and Pdk1−/− mice. (E) TPO levels of Pdk1fl/fl and Pdk1−/− mice. Arithmetic means ± SEM (n = 6, unpaired 2-tailed Student t test) are shown. TPO receptor/c-Mpl protein level in Pdk1fl/fl and Pdk1−/− MKs. Actin was used as loading control. Arithmetic means ± SEM (n = 5, unpaired 2-tailed Student t test) are shown. (F) Platelet counts of Pdk1fl/fl and Pdk1−/− mice before and 4 days after treatment with TPO (2 µg per animal per day). Arithmetic means ± SEM (n = 8, 2-way analysis of variance [ANOVA] with Bonferroni correction for multiple comparisons) are shown. (G) Endogenous survival of Pdk1fl/fl and Pdk1−/− platelets measured by determination of percent fluorescently labeled platelets in vivo at indicated time points after injection of DyLight 488 α-glycoprotein IX (GPIX) (n = 6, unpaired 2-tailed Student t test). (H) Platelet depletion in Pdk1fl/fl and Pdk1−/− mice was induced by IV injection of rat anti-GPIbα antibody (Emfret Analytics). Peripheral platelet counts were determined over a time course of 7 days by flow cytometry. The rate of platelet count recovery as compared with the respective initial platelet count is depicted (n = 4, unpaired 2-tailed Student t test). *P < .05 and **P < .01 as well as ##P < .01 indicate statistically significant differences.