Thpo deficiency inhibits cell cycle progression, induces apoptosis, and impairs mitochondrial function in HSCs. (A) PB platelet counts in Thpo^+/+ and Thpo^−/− mice (n > 5). (B) Representative flow cytometric plot of BM HSCs (Lin^- cKit⁺ Sca1⁺ CD48⁻ CD150⁺ CD34⁻) and quantification of BM HSC number in Thpo^+/+ and Thpo^−/− mice (n > 5). (C) Representative flow cytometric plot of cell cycle analysis of Thpo^+/+ and Thpo^−/− HSCs using Ki-67 and Hoechst 33342 staining. (D) Frequency of cell cycle states (G₀, G₁, S/G₂/M and subG₁) in Thpo^+/+ and Thpo^−/− HSCs (n = 4). (E) Representative flow cytometric plot and quantification (mean fluorescence intensity [MFI]) and percentage of positively gated cells) of Annexin V staining in Thpo^+/+ and Thpo^−/− HSCs (n = 4). (F) Representative flow cytometric plot and MFI of FSC parameter in Thpo^+/+ and Thpo^−/− HSCs (n = 4). (G) Representative flow cytometric plot and MFI of dendra2 fluorescence in Thpo^+/+;mito-dendra2^+/− and Thpo^−/−;mito-dendra2^+/− HSCs (n = 4). (H) Ratio of mitochondrial DNA (mtDNA)/nuclear DNA (nucDNA) quantified using qPCR in Thpo^+/+ and Thpo^−/− HSCs (n = 4). (I) ATP content measured in luminescence of Thpo^+/+ and Thpo^−/− HSCs (n > 5). *P < .05, **P < .01, ***P < .001, Student t test (A-B,E-I), Fisher’s least significant difference test (D).