Fig. 3. Dysregulation of mTOG-Ψ-driven translation control in HR-MDS-HSPCs predicts leukaemic progression.
a,b, Patients with reduced HSPC mTOG levels have decreased overall survival (a; n = 50) and increased risk of AML progression (b; n = 43). Log-rank test. b, Inset: inverse correlation (Pearson’s r) between the relative HSPC mTOG expression levels and BM blast counts in patients with MDS (n = 50). c, mTOG-Ψ represses translation in MDS-HSPCs. Representative flow cytometric analysis (middle) of de novo protein synthesis in HSPCs from healthy controls (HC) and MDS-HSPCs following treatment with SCR-Ψ or mTOG-Ψ as illustrated in the schematic (left). The changes in protein levels, determined through OP-puromycin labelling, of mTOG-Ψ relative to SCR-Ψ (mean ± s.e.m.) in four independent HC individuals and patients with MDS are shown (right). *P = 0.0311, Welch’s two-tailed t-test. d, Protein analysis of patient-derived BMMCs demonstrated increased expression of mTOG-Ψ targets in HR-MDS and sAML compared with the HC and LR-MDS groups (top). No differences in the relative EIF6, RPL23 and RPL29 mRNA levels in patient-derived BMMCs relative to the HC group were observed (bottom). One-way ANOVA with a multiple comparison test; n = 3 or 4, each dot represents a patient. e,f, Delivery of synthetic mTOG-Ψ (e) and siPAIP1 (f) selectively rescues the translation of 5′ PES-containing RPL29, RPL23 and EIF6 mRNA in patient-derived HR-MDS cells (left). The changes in protein abundance in mononuclear cells from different patients with HR-MDS treated with mTOG-Ψ (e) and siPAIP1 (f) relative to the controls (SCR-Ψ and siCtrl, respectively) are shown (right). Two-way ANOVA with a multiple comparison test; n = 3 patient samples, except for RPL23 in e, where n = 2; each dot represents a patient. e, **P = 0.0015 and *P = 0.0195. f, **P = 0.0025 and ***P = 0.0005. g, The mTOG-Ψ–PAIP1 axis modulates translation in PUS7-depleted MDS-L cells. Representative de novo protein synthesis and analysis of mTOG-Ψ-regulated 5′ PES-containing mRNA in MDS-L cells infected with shRNA targeting PUS7 (shPUS7) with or without mTOG-Ψ or siPAIP1 (20 nM) treatment (left). Relative protein synthesis in PUS7-KD MDS-L cells ± siPAIP1 or mTOG-Ψ (right). *P = 0.0215, *P = 0.0190 and ***P = 0.0001; one-way ANOVA with a multiple comparison test; n = 5 independent biological replicates. h, No changes in EIF6 and RPL29 transcription, relative to the control (shCTRL), were observed in the treatment groups in g. One-way ANOVA with a multiple comparison test; n = 6 independent biological replicates. d–h, Data are the mean ± s.d. NS, not significant.