LncRNA DLEU2 regulates sirtuins and mitochondrial respiratory chain complex IV: a novel pathway in obesity and offspring's health.

backgroundLong non-coding RNAs (lncRNAs) have emerged as a rapidly expanding area of interest in chronic diseases. They are mostly unknown for roles in metabolic regulation. Sirtuins, an epigenetic modulator class, regulate metabolic pathways. However, how sirtuins are regulated via lncRNA is unknown. We hypothesized that a high-fat high-fructose diet (HFD-HF) during pregnancy would increase the risk for obesity via lncRNA-Sirtuin pathways.

methodsFemale C57Bl/6 mice (F0) were fed either chow diet (CD) or HFD-HF for 6 weeks till birth. The pups (F1) were fed either CD or HFD-HF for 20 weeks. Expression of Dleu2, sirtuins, mitochondrial respiratory complexes, and oxidative stress were investigated in the F1 livers. Fasting blood glucose, insulin sensitivity, glucose tolerance, body and tissues weight were measured. A mechanistic interaction was then carried out using a DLEU2 knockdown experiment in the HepG2 cell.

resultsDleu2 and sirtuins were both significantly decreased in the livers of HFD-HF fed male F1 whose mothers were either fed CD or HFD-HF during reproductive and pregnancy windows. Confirming this connection, upon silencing DLEU2, transcription levels of SIRT1 through 6 and translational levels of SIRT1, 3, 5, and 6 were significantly downregulated. Knockdown of DLEU2 significantly decreased the protein level of cytochrome-c oxidase (complex IV, MTCO1) without altering other mitochondrial complexes, decreased mitochondrial membrane potential, decreased ATP, and increased reactive oxygen species. Interestingly, in F1 livers, the protein level of MTCO1 was also significantly decreased under an HFD-HF diet or even under chow diet if the mother was exposed to HFD-HF.

conclusionOur findings reveal for the first time that one lncRNA can regulate sirtuins and a specific mitochondrial complex. Furthermore, diet or maternal diet can modulate Dleu2 and its downstream regulators in offspring, suggesting a potential role of DLEU2 in metabolic disorders over one or more generations.