Fig. 5: Peripheral enrichment of H3K9 trimethylated chromatin is abrogated in adult CMs in a mouse hypertrophy model and correlates with cardiac performance in human patients.

a) Mice were treated with angiotensin II (AngII, n=4) to induce cardiac hypertrophy. AngII receiving mice showed a reduction in heart performance (ejection fraction) and an increase in heart weight (left ventricle) after 28 days of treatment compared to day 0, while saline receiving control mice (n=5) showed no difference (see also Extended Table 5); 2W-ANOVA: * p<0.05, *** p<0.001. b) After 28 days, hearts were harvested and stained for H3K27me3 and H3K9me3. DAPI was used as DNA counterstain. c, d) Immunostained cardiac sections of hypertrophic (AngII) or control mice (Saline) were analyzed for peripheral enrichment of overall (DAPI) or epigenetically marked chromatin and enrichment scores were calculated. Enrichment of overall and methylated chromatin was abrogated in cardiac nuclei of hypertrophic mice. SEM; n≥40 from 4 (AngII) or 5 (saline) exp.; T-test: * p<0.05, ** p<0.01; all scales=5 µm. e-g) Human heart samples from patient suffering from either nonischemic cardiomyopathy (NICM, n=3), or control patients with no heart failure (NHF, n=3), were stained for overall chromatin (DAPI), as well as H3K9 and H3K27 trimethylated chromatin. Peripheral enrichment of all markers was markedly reduced in NICM patients, compared to control patients. T-test: * p<0.05, ** p<0.01, *** p<0.001. h) Peripheral enrichment scores were correlated with indicators of cardiac health, with peripheral enrichment of H3K9me3 and ejection fraction showing the highest adjusted correlation coefficient. LV=left ventricle.