Systemic analysis shows that cold exposure modulates triglyceride accumulation and phospholipid distribution in mice

Environmental exposure to cold is increasingly being associated with changes in metabolism. We developed and tested the hypothesis that exposure to cold drives systemic effects in lipid metabolism. Specifically, (i) that energy storage and provision adapts to the cold by altering triglyceride distribution and (ii) that membranes adapt to cold conditions by becoming more unsaturated. These hypotheses were designed to identify the underlying mechanisms that govern the response of mammalian systems to cold. To test these hypotheses, we used a metabolic network analysis. An established model of cold exposure was used, from which lipidomics data that represents the system was collected. The network analysis showed that triglyceride metabolism is altered on exposure to cold, with several smaller effects that are not straightforward, such as changes to the abundance and distribution of odd chain fatty acids. The range and profile of phosphatidylcholine and phosphatidylinositol were modified, but there was little change in phosphatidylethanolamine or sphingomyelin. These results support the hypothesis, and show that exposure to cold is a system-wide phenomenon that requires or drives changes across a range of metabolic pathways.