Figure 2. Altered ASAH1-related metabolites in senescence. (A) Schematic representation of the metabolic pathway of ceramides conversion to sphingosine and fatty acids by ASAH1. Ceramides are also converted to sphingomyelin during sphingolipid biosynthesis or generated during sphingolipid recycling. (B, C) Metabolomic analysis of the levels of ceramides, fatty acids, and sphingomyelin during replicative (B) or IR-induced (C) senescence. Dashed lines indicate p < 0.05. The x-axis indicates the categories and individual metabolites. Red bars indicate a log odds ratio (OR) > 1: an increased log odds of a higher metabolite concentration in the Replicatively senescent (B) or IR-induced senescent (C) group relative to the comparison group (Proliferating). Blue bars indicate a log odds ratio (OR) < 1: a decreased log odds of a higher metabolite concentration in the Replicatively senescent (B) or IR-induced senescent (C) group relative to the comparison group (Proliferating). Significant metabolites are highlighted in the table below each graph.