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. 2021 Jul 28;22(15):8089. doi: 10.3390/ijms22158089

Figure 2.

Figure 2

(A) Lipid class enrichment analysis results based on the comparison between treated and control animals. Left: normalized enrichment scores (NES). Positive NES corresponds to an increase in the lipid abundances in treated animals, and negative NES corresponds to decrease. Colors mark lipid classes demonstrating significant enrichment in the treatment-control differences. Right: adjusted enrichment p-values. The dashed line corresponds to the adjusted p-value cutoff of 0.05. (B) Base two log-transformed fold change (log2 FC) values calculated between treated and control animals for lipids in free fatty acid (FFA) class. X-axis labels indicate fatty acid chain length and number of double bonds. FFAs are ordered by increasing unsaturation. Blue symbols mark compounds with nominal t-test p < 0.05. Asterisks mark statistically significant compounds (t-test; FDR = 10%, permutations p = 0.0008). The dashed line indicates log2 FC = 0. (C) Log2 FC values calculated between treated and control animals, averaged for all the lipids with the same level of unsaturation (number of double bonds). Lipids were first separated into groups based on the number of fatty acid residues, one (dark blue), two (green), or three (light blue), and sphingolipids were excluded. The black dashed line indicates log2 FC = 0. Colored dashed lines indicate linear regression lines fitted to each group (p = 0.0054, 0.54 × 10−5 and 0.00022 for lipid classes containing one, two and three fatty acid residues, respectively). (D) Abundance levels of docosahexaenoic acid (DHA) and arachidonic acid (AA) in treated and control animals. Symbols represent individual samples. Colors correspond to treatment status, shapes to the MAOA genotype. Asterisks mark statistically significant differences between treatment and control (t-test; FDR = 10%, permutations p = 0.0008). (E) The cumulative abundances of lipids contained in FFA, LPE, PE, HexCer;O2, and HexCer;O3 lipid classes (colors as in panel A) for each level of unsaturation (number of double bonds per compound). Cumulative abundances were normalized between the lipid classes.