Fig. 7: Rescue of p300 mislocalization alleviates ageing features of HGPS cells.
a, Rescue of increased DNA damage (γ-H2AX) in HGPS fibroblasts by treatment with p300 inhibitor A485 for 24 h. The blots are representative of three biologically independent experiments (N = 3). One-way ANOVA with post hoc Tukey test. Data from control vials #1 and #2 were pooled as these are from the same individual (Supplementary Table 1). b, Rescue of DNA damage by progerin using A485. Arrow, induced cells and arrowhead, not induced cells. Scale bar, 5 μm. N = 3. c, Rescue of reduced lamin B1 levels in HGPS fibroblasts by treatment with A485, 991 or SEL. Scale bar, 5 μm. N = 3, about 50 cells scored per condition. One-way ANOVA with post hoc Tukey test. d, Decreased H3K9me3 expression level by progerin induction for 48 h. *GFP–progerin-induced cells, #not GFP–progerin-induced cells. Scale bar, 5 μm. N = 3, about 50 cells scored per condition. One sample t-test. e, Rescue of reduced H3K9me3 level in HGPS fibroblasts by treatment with A485, 991 or SEL. Scale bar, 5 μm. N = 3, about 40 cells scored per condition. One-way ANOVA with post hoc Tukey test. f, Altered mitochondrial morphology by progerin induction for 48 h. *GFP–progerin-induced cells, #not GFP–progerin-induced cells. Scale bars, 5 μm and 1 μm (enlarged images). N = 4, about 50 cells scored per condition. Two-tailed unpaired t-test. g, Rescue of defect in mitochondrial morphology in progerin-expressing cells by treatment with A485, 991 or SEL (N = 4, about 50 cells scored per condition). Two-tailed unpaired t-test. h, Rescue of reduced H3K9me3 level in HGPS cells by 991 or SEL is mediated by p300 localization using His-tagged p300 dNLS mutant. The expression levels following transfection are depicted by the quantification of the His-tag (N = 4). One-way ANOVA with post hoc Tukey test. i, A schematic diagram of this study. Depletion of nutrients causes cytoplasm-to-nucleus relocalization of p300, reducing mTORC1 activity and activating autophagy. This is mediated by AMPK-dependent phosphorylation of p300 at serine 89. Nutrient addition to starved cells results in PP2A-dependent dephosphorylation of nuclear p300, enabling its CRM1-dependent export to the cytoplasm to mediate mTORC1 reactivation. In HGPS cells, p300 cytoplasm–nucleus shuttling is altered, causing mTORC1 hyperactivation and autophagy inhibition. Modulating p300 shuttling normalizes HGPS phenotypes. Data are presented as mean values ± s.d. unless otherwise specified. Source numerical data and unprocessed blots are available in the source data.
