In vivo effect of Flavonoids modulates ATM (adipocytes-macrophage infiltration) in Drosophila’s models of obesity

Obesity is a pathological condition associated with cardiovascular disorders, type 2 diabete and chronic inflammation also called Adipocyte Tissue Macrophage Infiltration (ATM). Obesity is caused by the interplay of more elements: environmental toxins, sedentary lifestyle and diet. Accumulation of fats in metabolically active sites, such as adipose tissue and liver, causes the increase of proinflammatory cytokines and of the circulating level of free fatty acids (FFAs). These responses result in increased oxidative stress levels caused by release of reactive oxygen species (ROS), that cause adipocyte macrophage infiltration, with a mechanism poorly understood. In obese people the immune cells infiltrate the adipose tissue to promote a chronic inflammatory state. Similarly to vertebrates, Drosophila's circulating immune cells of the hemolymph, called hemocytes, infiltrate the fat body in obese animals. During development, the fat body controls relevant metabolic pathways and inflammation, contributing to the maintenance of the animal energy homeostasis. In our laboratory we are interested in understanding if bioactive compounds, like flavonoids, phenolic compounds found in fruits and vegetables that have anti-oxidant function, may exert a protective action against obesity and ATM due to their anti-oxidant activity. We performed feeding experiments using different models of obesity: 1-High Fat Diet (HFD), 2-genetic reduction of brummer/ATGL human adipocyte triglyceride lipase and 3-genetic ablation of ecdysone. Our results demonstrated that the presence of flavonoids, in particular of anthocyanin-rich food, reduces hemocytes infiltration in larval fat body. We are relating this effect to a potential inhibition of ROS and cytokines released from the fat body, data will be presented.