Omega-3 fatty acids partially revert the metabolic gene expression profile induced by long-term calorie restriction

Calorie restriction (CR) consistently extends longevity and delays age-related diseases across several animal models. We have previously shown that different dietary fat sources can modulate life span and mitochondrial ultrastructure, function and membrane fatty acid composition in mice maintained on a 40% CR. In particular, animals consuming lard as the main fat source (CR-Lard) lived longer than CR mice consuming diets with soybean oil (CR-Soy) or fish oil (CR-Fish) as the predominant lipid source. In the present work, a transcriptomic analysis in the liver and skeletal muscle was performed in order to elucidate possible mechanisms underlying the changes in energy metabolism and longevity induced by dietary fat in CR mice. After 8 months of CR, transcription downstream of several mediators of inflammation was inhibited in liver. In contrast, proinflammatory signaling was increased in the CR-Fish versus other CR groups. Dietary fish oil induced a gene expression pattern consistent with increased transcriptional regulation by several cytokines (TNF, GM-CSF, TGF-β) and sex hormones when compared to the other CR groups. The CR-Fish also had lower expression of genes involved in fatty acid biosynthesis and increased expression of mitochondrial and peroxisomal fatty acid β-oxidation genes than the other CR diet groups. Our data suggest that a diet high in n-3 PUFA, partially reverts CR-related changes in gene expression of key processes, such as inflammation and steroid hormone signaling, and this may mitigate life span extension with CR in mice consuming diets high in fish oil.