Fig. 3

Heatmap showing genes identified as maximally differentially regulated in the animal model of PA pneumonia. This heatmap depicts the top 35 differentially expressed genes between the four groups: WT Control (WT CTRL), WT PA infection (WT PA), Sphk2^−/− control (Sphk2^−/− CTRL), Sphk2^−/− PA infection (Sphk2^−/− PA). “Pathway Maps” ontology was used to analyze differentially expressed genes. 50 most enriched pathways (PW) were identified, and nodal PWs were clustered based on their gene content with stress on reduced duplication. Initially, a complete linkage hierarchical clustering on the Jaccard distance between the complete set of genes in each PW was done. This was followed by identification of closely related individual entities. Using a dissimilarity cut off of 0.6, each cluster of closely related PWs was taken as one mega pathway. Heatmaps were created by combing the associated differential genes in order to analyze gene interactions. Details of clustering pathways has been shown in Table 1. The color key shows the z-scored normalized expression level ranging from dark blue to dark red. The corresponding degree of differential regulation ranges from − 2 of down regulation or more to + 2 of upregulation or more