Figure 3.
Lipid overload induces sphingolipid-dependent oxidative stress in a manner similar to CerS2 overexpression. A, B) Elevated ROS was detected in AC16 cells overexpressing CerS2 compared with control cells by CellROX detection of superoxide. Superoxide formation (red) was induced by palmitate (16 h) in cardiomyocytes (H9c2) and was rescued by myriocin cotreatment. C, D) H2O2 served as a positive control for superoxide formation, and myriocin exhibited no protective effect in cardiomyocytes. Similarly, increased lipid peroxidation (detected by 4-hydroxynoneal formation; green) in cardiomyocytes (H9c2) was induced by palmitate (16 h). E, F) Coincubation with sphingolipid inhibitor myriocin rescued from this increase. Student’s t test and 1-way ANOVA. *P < 0.05, **P < 0.01 compared with control (ctrl), $$$P < 0.05 compared with palmitate (n = 3–7). Scale bars, 40 µm (A); 100 µm (B).