Impact of the metabolic program of germline cells on feeding behaviour

• Autor(a) principal: Figueiredo, Rita Cardoso
• Data de Publicação: 2018
• Tipo de documento: Dissertação
• Idioma: eng
• Título da fonte: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
• Texto Completo: http://hdl.handle.net/10362/56822
• topic: Drosophila; feeding; behaviour; metabolism; PPP; Domínio/Área Científica::Engenharia e Tecnologia::Engenharia Química

Animals control how much and what they eat to ensure an optimal nutrient balance for organismal function. Drosophila melanogaster shows specific nutrient appetites depending on its internal nutrient and mating state. We hypothesize that the Central Nervous System (CNS) is able to read the nutritional requirements of several organs and adapt feeding behavior to maintain tissue nutrient homeostasis. Oogenesis is a highly metabolically demanding process, strongly responding to nutrient availability and a large part of carbohydrates ingested by females are used for egg production. Females without germline show a strong reduction in sugar appetite even when carbohydrate-deprived, suggesting that indeed the CNS can sense the nutrient requirements of this organ and instruct the animal to behave accordingly. We hypothesize that carbohydrate metabolism in the germline might underlie this modulation of sugar appetite. To address this hypothesis, we took advantage of Drosophila melanogaster’s vast array of genetic and molecular tools, together with a high precision quantitative assay for fly feeding behaviour (flyPAD) and a full synthetic diet that allows precise nutrient manipulations of the diet. We show that dietary sugar is key for maintaining optimal egg production, since dietary sucrose deprivation reduces egg-laying by 37%. Furthermore, we show that egg production is highly dependent on the Pentose Phosphate Pathway (PPP) as we show that down-regulating the levels of enzymes in this pathway leads to a drastic reduction in egg-laying. Finally, we also show that the PPP in the germline modulates sugar appetite. Our data supports a model where the germline cellular metabolic program is surveyed by the CNS to modulate the uptake of carbohydrates in order to achieve high fertility. It will be interesting to explore if pathologies in which cellular metabolic programs are altered, such as in certain tumors, also impinge on appetites in order to obtain the required nutrients for disease progression.