Sexual Dimorphism in Metabolic Responses to Western Diet in Drosophila melanogaster.

Sofie De Groef,Tom Wilms,Séverine Balmand,Patrick Callaerts,Federica Calevro

doi:10.3390/biom12010033

Abstract

Obesity is a chronic disease affecting millions of people worldwide. The fruit fly (Drosophila melanogaster) is an interesting research model to study metabolic and transcriptomic responses to obesogenic diets. However, the sex-specific differences in these responses are still understudied and perhaps underestimated. In this study, we exposed adult male and female Dahomey fruit flies to a standard diet supplemented with sugar, fat, or a combination of both. The exposure to a diet supplemented with 10% sugar and 10% fat efficiently induced an increase in the lipid content in flies, a hallmark for obesity. This increase in lipid content was more prominent in males, while females displayed significant changes in glycogen content. A strong effect of the diets on the ovarian size and number of ma-ture oocytes was also present in females exposed to diets supplemented with fat and a combina-tion of fat and sugar. In both males and females, fat body morphology changed and was associ-ated with an increase in lipid content of fat cells in response to the diets. The expression of me-tabolism-related genes also displayed a strong sexually dimorphic response under normal condi-tions and in response to sugar and/or fat-supplemented diets. Here, we show that the exposure of adult fruit flies to an obesogenic diet containing both sugar and fat allowed studying sexual dimorphism in metabolism and the expression of genes regulating metabolism.

Highlights

Obesity is a chronic disease associated with a major socio-economic health impact.Almost two billion adults worldwide are overweight, of whom 650 million are diagnosed as obese [1]
TAG Content Increases in Response to 10% Increase in Dietary Sucrose and Fat
In a dose–response experiment, we aimed to identify nutritional conditions that led to an increase in stored TAG in adult fruit flies (Figure S1)

Summary

Introduction

Obesity is a chronic disease associated with a major socio-economic health impact.Almost two billion adults worldwide are overweight, of whom 650 million are diagnosed as obese [1]. Obesity-associated disorders such as diabetes and cardiovascular disease are often more prevalent in men. Despite these disparities, the inclusion of both sexes is often lacking in fundamental metabolic research [2]. Unraveling the molecular basis of sex differences in metabolism will likely be relevant to help reduce the numbers of patients with obesity and provide better treatments. Despite physiological differences in development and metabolism, studies in Drosophila melanogaster have contributed significantly to our understanding of molecular and genetic mechanisms in metabolic regulation in mammals, including humans [3]. Diet-induced obesity in Drosophila leads to fat accumulation in the form of increased triglyceride (TAG) content and lipid droplet number and size [5,6]. Many studies using obesogenic diets investigate larvae or adult flies reared on high-sugar diets

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Conclusion