RNA-seq analysis of diet-driven obesity and anti-obesity effects of Quercetin glucoside or Epigallocatechin gallate in Drosophila adults.

The High Fat Diet (HFD)-feeding significantly stimulated fat accumulation in Drosophila adults. Simultaneous feeding of known anti-obesity drugs that having the effect on rat and mouse, Quercetin Glycosides (QG) and Epigallocatechin gallate (EGCG) also suppressed fat accumulation in Drosophila at an equivalent concentration. Therefore, we have established a convenient model system to study on diet-induced fat accumulation and to evaluate effects of anti-obesity drugs using Drosophila. To understand overview of alterations of gene expression due to diet-induced fat accumulation and its suppression by the known anti-obesity drugs, we performed the RNA seq analyses. Consequently, mRNA levels of several genes involved in lipid metabolism, glycolysis/gluconeogenesis and anti-oxidative stress have changed in adults fed the HFD. Moreover, the levels altered in those fed on HFD supplemented with QG or EGCG. Our qRT-PCR further confirmed the RNA-seq data suggesting that expression of five genes essential for lipid metabolism was changed in HFD-fed animals and further altered in the animals treated with anti-obesity drugs. Among them, the most remarkable alteration was observed in dHSL gene encoding a lipase involved in lipid-storage after HFD feeding and the HFD supplemented with QG or EGCG. These changes are consistent with HFD-induced fat accumulation as well as the anti-obesity effects of those two drugs in mammals, suggesting that these genes play an important role in the anti-obesity effects of the drugs. These are the first evidences that whole profiles of altered gene expression under a condition of a diet-induced obesity and its suppression by anti-obesity drugs in Drosophila. mRNA profiles of Drosophila fed on Normal diet (ND), high fat diet (HFD), HFD supplemented with QG or EGCG were generated by RNA sequencing, 1 replicate performed per group.