Adipose lipidomics and RNA-Seq analysis revealed the enhanced mitochondrial function in UCP1 knock-in pigs

Abstract Uncoupling protein 1 (UCP1) plays a key role in nonshivering thermogenesis and is involved in the pathogenesis of obesity. In a previous study, we generated adipocyte-specific UCP1 knock-in ( UCP1 -KI) pigs, which exhibited improved thermoregulatory ability and decreased fat deposition. To investigate whether UCP1 knock-in alters the lipid composition of adipose tissues, lipidomics of inguinal subcutaneous white adipose tissue (iWAT) and backfat from 6-month-old cold-treated UCP1 -KI pigs and wild-type (WT) pigs were profiled. In addition, genome-wide RNA-sequencing of iWAT was performed to further study the genetic basis for lipid alterations. The results showed that iWAT and backfat from UCP1- KI pigs exhibited distinct lipidomic profiles, as the mild lipid alteration was observed in backfat of UCP1 knock-in pigs. Inguinal WAT from UCP1 -KI pigs contained significantly decreased total triacylglycerol ( p UCP1 -KI pigs. Significantly increased levels of total sphingolipids ( p UCP1 -KI pigs. Notably, two mitochondrial-specific lipid species, cardiolipin CL72:8 (18:2) and CL74:9 (18:2), were found to be dramatically increased in iWAT from UCP1 -KI pigs, suggesting enhanced mitochondrial function. This observation was further supported by the significant upregulation of numerous mitochondrial-related genes and significantly increased number of large mitochondria and mitochondrial cristae in iWAT of UCP1 -KI pigs. Taken together, these data illustrate the specific role of UCP1 in lipid metabolism of fat tissues in pigs and provide new data for characterization of fat traits in UCP1 -KI pigs.