OPLS-DA and WGCNA identified 16 significantly changed lipid species in the ischemic penumbra. (A) Diagram showing the experimental design. (B) The plot depicting separation of the d1-con (d2-con, d3-con) and d1-ip (d2-ip, d3-ip) utilizing the OPLS-DA model. (C) Venn diagram of significantly changed lipid species between ischemic penumbra and corresponding contralateral area among 3 days. Lipid species with VIP > 1.0 in the OPLS-DA model, fold change (FC) > 1.5 and statistical significance (p < 0.05, t-test) between ischemic penumbra and corresponding contralateral area are considered as significantly regulated lipid species. (D) The soft-thresholding powers selection of WGCNA analysis. The left panel shows the scale-free fit index (y-axis) as a function of soft-thresholding power (x-axis). The red line represents the y-axis value and here the adjacency matrix is defined using soft-thresholds with beta = 7. The right panel shows the mean connectivity (y-axis) as a function of soft-thresholding powers (x-axis). (E) Clustering dendrograms of lipid species, with dissimilarity based on topological overlap, together with assigned module colors. (F) The module-group relationship heatmap. Each column corresponds to a group. Each row corresponds to a module, labeled with a color as in Fig. 1E. The first line in every square is the corresponding correlation coefficient and the second line is the p-value. The left side of heatmap indicates the module name and the number of lipid species is indicated. The right side of heatmap indicates the colors of correlation (blue represents negatively correlated and red represents positively correlated). Modules with significantly changed lipid species are indicated with red underlines. (G) Venn diagram displaying the overlapping lipid species in WGCNA modules (magenta, greenyellow and pink modules, Fig. 1F) and OPLS-DA models (Fig. 1C). (H) Heatmap showing the abundance of 16 overlapping lipid species in ischemic penumbra and corresponding contralateral area among 3 days. (I) ROC curve for individual lipid specie in (Fig. 1H) to separate ischemic penumbra from corresponding contralateral area. (For interpretation of the references to color in this figure legend, the reader is referred to the web version of this article.)