Fig. 4: Global miRNA expression dynamics in brain aging across regions.

All samples from the dataset are considered. a Heatmaps showing deregulated miRNAs between each older age and 3 months (fold change \(\ge\) 1.5 or \(\le\) 1/1.5). Numbers shown if \(\ge\)200 miRNAs. On the left, significantly anti- or positively correlated miRNAs with age are given (|R| \(\ge\) 0.5, Spearman’s rank correlation coefficient, adjusted p-value < 0.05, two-sided Spearman’s rank correlation test, Benjamini-Hochberg). b Upset plot of miRNAs changing significant with age per brain region, indicating unique and overlapping candidates. Significant candidates from Fig. 4a and Supplementary Fig. 4e. Brain regions above the age variance threshold in Fig. 2c are bold. Regions with <10 candidates and combinations with <5 miRNAs are omitted. c Trajectory clustering overview (k = 53, minimum membership 15%). Each dot represents a cluster, sized by cluster size. Dot color indicates brain region if occurrence exceeds 30%, dark green if the most frequent features incidence exceeds 4, otherwise light green. d Center lines of clusters with brain region occurrence >30%, highlighting choroid plexus and pons. e Trajectories of four selected clusters (z-scored miRNA expression). Yellow plots show a steady increase, green plots steady decrease with age. Labels show dominant regions (>10%) and frequent miRNAs (>3 features). Regions with black borders and bold miRNAs exceed the thresholds from Fig. 4c. f Detailed view of brain region occurrence (left) and miRNA frequency (right). Brain regions (<10%) and miRNA (<3) are omitted. Dots over thresholds from Fig. 4c (grey dashed lines) appear in dark green for miRNAs or have black borders for brain regions. g Center lines of seven clusters containing mmu-miR-155-5p trajectories. Line widths vary if multiple regions share a center line. h Boxplots of mmu-miR-155-5p trajectories in seven brain regions. Asterisks highlight significant comparisons to 3 months (fold change \(\ge\) 1.5 or \(\le\) 1/1.5, adjusted p-value < 0.05, two-sided Welch’s \(t\)-test, Benjamini-Hochberg procedure). Spearman’s rank correlation coefficient with age are displayed above each plot (significantly, if adjusted p-value < 0.05, two-sided Spearman’s rank correlation test, Benjamini-Hochberg). Boxplots follow Fig. 1c and Methods; exact values in Supplementary Data 7 and 8.