An integrated multi-omics approach revealed the regulation of melatonin on age-dependent mitochondrial function impair and lipid dyshomeostasis in mice hippocampus

Melatonin can improve mitochondrial dysfunction associated with the aging process by removing active oxygen, as well as inhibiting lipid peroxidation to maintain biofilm fluidity and resist free radical attack. However, there is poor understanding of the effect of melatonin on age-dependent mitochondrial function and lipid profile changes in brain. In this study, we investigated the energy metabolism of the whole body and brain of mice at 9 months, 13 months, and 25 months of continuous gastric administration of 3 mg/kg/d melatonin once per day morning for two months. In addition, we performed transcriptomic, proteomic and lipidomic analysis in the hippocampus of mice at different ages. Proteomics showed that melatonin regulated mitochondrial electron transport and leucine degradation in mouse hippocampus. Lipomics suggested that the long-chain unsaturated glycerol phospholipids in mouse hippocampus increased in an age-dependent manner, while ceramide and glycerol phospholipids decreased significantly in hippocampus of mouse chronically exposed to melatonin. The combined analysis of proteome and liposome demonstrated that Mpst, Ccsap, Hdhd5, Rpl5 and Flna were the key proteins of the network which involved in the regulation of numerous lipids. Furthermore, ultrastructure observation results illustrated that melatonin could improve the damaged mitochondrial and morphologies of 25-month-old mice hippocampus. In conclusion, we describe a mechanism that age-dependent up-regulation of long-chain unsaturated lipids is a driving risk factor for mitochondrial damage and this effect could be reversed by chronic supplement of low-dose melatonin.