Fig. 1: miRNA expression volcano plot, heatmap, gene ontology prediction, and IPA analysis in total fraction.

Normalized values of 333 detectable miRNAs were plotted in an expression volcano plot and heatmap with hierarchical clustering. a miRNAs with high expression are shown with green color on the map; miRNAs with low expression are shown in red. For the clustering purposes, the Euclidean method was used to measure the distance, and the average linkage algorithm was applied to calculate the average pairwise distance between all pairs of points. Following the average linkage clustering algorithm, the dendrogram was constructed to demonstrate the expression similarities. b Volcano plot of genes differentially expressed between control and MDD groups. The y-axis corresponds to the significance level represented with log₁₀P value, and the x-axis displays the log2 (FC) value. The red dots represent the significantly (p ≤ 0.05) overexpressed genes in MDD (FC ≥ 1.3); The blue dots represent the significantly (p ≤ 0.05) under expressed genes (FC ≤ 1.3) in MDD; the green dots represent the genes whose expression levels did not reach statistical significance (p ≥ 0.05) but expression level was higher (FC ≥ 1.3) in MDD group. c Significantly altered miRNAs in the total fraction of dlPFC from MDD subjects. Out of 333 miRNAs, 4 miRNAs and 18 miRNAs were significantly up- or downregulated in MDD subjects, respectively. d GO analysis for biological process conducted with predicted target genes by significantly altered miRNAs showing significant enrichment of terms in various categories associated with neuronal functions. The lower p value is shown as blue color, and the circle size means the number of gene counts in each GO term. IPA analysis was performed with predicted target genes for significantly up- and downregulated miRNAs separately for canonical pathway (e) and disease and function (f). The results from up- and downregulated miRNA are shown as blue and orange colors respectively.