Discovery And Function Of A New LncRNA That Regulates Lipid Metabolism

Long non-coding RNAs(lncRNAs)are a group of RNAs which transcript length is 200 to 100000 nt,it lacks a coding protein open reading frame(ORF).LncRNAs have long been considered to be unfunctional,but recent studies have found that lncRNAs are widely involved in various physiological and pathological processes by interacting with chromatin,proteins and other RNA.LncRNA can regulate lipid metabolism has been reported.However,the roles and function mechanisms of lncRNA in cholesterol metabolism still remain elusive.In this project,we aim to identify some lncRNAs involved in cholesterol metabolism and their mechanisms.Cholesterol is a kind of steroid that contains the carbon skeleton of cyclopentanoperhydro-phenanthrene,which plays an important physiological role in the body.In mammals,cholesterol is the main components of the cell membrane and the synthetic precursor of many bioactive molecules,the cholesterol modified protein is also a important form for modification.Liver is an important metabolic organ of cholesterol.We use mice as animal models to screen the lncRNA involved in cholesterol metabolism in mouse liver.We analyzed the differentially expressed lncRNA profiles of the liver tissue between High Cholesterol Diet(HCD)fed mice and Lovastatin&Ezetimibe Diet(LED)fed mice using lncRNA microarrays.Based on bioinformatics data and RT-PCR results,a particular lncRNA was selected to next research,and we named it P5.3.Our results showed that P5.3 is highly expressed in myocardium,muscle and brown adipose tissue(BAT).The expression level of P5.3 was increased by cholesterol levels and during the transition from the fasted to the fed state.Overexpression of P5.3 affects the activity of the mitochondria complex ?,suggesting that P5.3 may play a role in energy metabolism of mitochondria and participate in the regulation of biological processes.At the cellular level,the overexpression of P5.3 will significantly increase ATP content and glocose consumption of cell,while RNAi knockdown corresponded to decrease.After the gene silencing of P5.3,the generation of ROS was significantly increased,while cell growth was significantly inhibited.At the animal level,adeno-associated virus(AAV)mediated overexpression of P5.3 in the liver inhibited hepatic steatosis and alleviated metabolic abnormalities in mice with diet-induced obesity(DIO),including decreases in liver weight,concentrations of triglycerides in the liver and cholesterol in the serum,fasting glucose and insulin levels,and homeostatic model assessment of insulin resistance(HOMA-IR),as well as improved performance on GTT and increased O2 consumption during both the light and dark phase.In summary,through the extensive screening verification experiment,we succeeded finding a lncRNA-P5.3 that involved in cholesterol or lipid metabolism,functional experiments show that the IncRNA may effect on mitochondrial complex III to influence the activity of the mitochondria,affecting the glucolipid metabolism of the cells.The study further improved our understanding of the body's cholesterol metabolism balance control,and to find new drug targets.