Fig. 1.

Age-related changes in the LV proteome of mouse heart tissue.A, schematic workflow of proteomics experiments. The proteome of left ventricular heart tissue from 20-month-old mice (old) was compared to the proteome of young mice (3 months). Both age groups were analyzed by TMT-based quantitative mass spectrometry. Five male C57BL/6 mice were used for each age group. B, PCA plot shows the correlation of age-related alterations. Ellipses represent 95% confidence intervals. The percentage of variance is shown for each principal component (PC). C, number of all quantified protein groups and up- and down-altered proteins. The percentage of significantly affected proteins indicated in dark blue (adj. p < 0.25) was calculated based on the total number of proteins in each column. D, Volcano plot showing the significant up- (red) and down-regulated (blue) proteins (adj. p value <0.25 and absolute log2 fold change >0.58) comparing old vs young LV proteome. Proteins not affected are shown in grey.E, compartmental analysis displaying the proportion of significantly age-affected proteins (adj. p < 0.25) for each cellular compartment. In the plot, “er” represents the endoplasmic reticulum and “extracellular” includes ECM and ECM-associated proteins. F, gene set enrichment analysis (GSEA) shows the 20 most affected pathways during ageing. GSEA was performed using WebGestalt (64). NES: Normalized Enrichment Score; FDR: False Discovery Rate. G, heatmap exhibiting all age-altered ECM and ECM-associated proteins (adj. p < 0.25) and with an absolute fold change (log2) greater than 0.5.