Abstract
Caffeine intake is strongly linked to lipid metabolism. We previously reported the age-dependent physiological effects of caffeine intake in a Caenorhabditis elegans model. Since nutritional status can actively influence metabolism and overall health, in this study, we evaluated the effect of caffeine intake on lipid metabolism in adult-stage C. elegans. We found that, in C. elegans, fat storage and the level of phosphoethanolamine (PE) were significantly reduced with caffeine intake. In addition, mitochondrial activity decreased and mitochondrial morphology was disrupted, and the expression of oxidative stress response genes, hsp-6, gst-4, and daf-16, was induced by caffeine intake. Furthermore, the level of an energy metabolism sensor, phospho-AMP-activated protein kinase, was increased, whereas the expression of the sterol regulatory element binding protein gene and its target stearoyl-CoA desaturase genes, fat-5, -6, and -7, was decreased with caffeine intake. These findings suggest that caffeine intake causes mitochondrial dysfunction and reduces lipogenesis. Interestingly, these changes induced by caffeine intake were partially alleviated by PE supplementation, suggesting that the reduction in mitochondrial activity and lipogenesis is in part because of the low PE level, and proper dietary supplementation can improve organelle integrity.