Objective: Ceramide, the backbone of sphingolipids, is the key component affecting atherosclerotic changes through its important second-messenger role. Previous studies have demonstrated protective role of AMP-activated protein kinase (AMPK) genes in regulating atherosclerosis and hypertension. Ceramide synthase 5 (LASS5 or CERS5) gene has function in de novo synthesis of ceramide, and has indirect effect on AMPK gene. Aim of the present study was to identify role of LASS5 gene in atherosclerosis.
Methods: LASS5 gene-specific small interfering RNA (siRNA)-mediated gene silencing was performed in human umbilical vein endothelial cells (HUVEC) and differential expression of LASS5, AMPK-alpha and AMPK-alpha target genes were analyzed. HUVEC cells were then treated with AMPK activator in order to examine relationship of change in gene expression levels to AMPK activity.
Results: Novel physiological function of LASS5 was identified. Downregulation of LASS5 was found to attenuate ceramide production and increase expression of some AMPK target genes in HUVEC.
Conclusion: This is the first study to demonstrate that LASS5 was involved in negative regulation of atherosclerosis-related genes, such as AMPK-alpha. These preliminary findings provide insight into molecular mechanism of atherosclerosis and are important for development of potential therapeutic agents in the treatment of atherosclerosis.