Abstracts (first author)
The role of Drosophila insulin-like peptides in nutrient-dependent lifespan and reproductionPDF
Dietary restriction (DR), a reduction in food intake without malnutrition, is a well-studied topic in ageing research. However, knowledge about mechanisms mediating this response is scarce. We know the Insulin-IGF Signalling (IIS) pathway is involved in ageing in many organisms. In Drosophila, insulin-like peptides (DILPs), upstream components of IIS, respond to different food conditions and a dilp2-3,5 knockout extends lifespan. This suggests that dilps can have a role in mediating the DR response. We investigated the role of dilps in nutrient-altered ageing by determining lifespan, fecundity and brain-dilp expression of the long-lived dilp2-3,5 knockout mutant (d235∆)and its genetic control (wDah) on a range of food types that differed in sugar and yeast concentration. We showed that d235∆ flies had an increased lifespan and decreased reproduction on all food types compared to wDah flies. There was still a nutrient-dependent lifespan and reproduction response for d235∆ flies, but the effect of the highest sugar and yeast concentrations was reduced for both lifespan and fecundity. For gene expression, in wDah flies dilp2 and -3 expression increased on high yeast and lower sugar concentrations, dilp5 expression increased on high yeast concentrations and dilp6 expression did not change on different sugar or yeast concentrations. Interestingly, in d235∆ flies dilp6 expression increased on high yeast concentrations. This data shows that dilp2, 3 and 5 may have a role but are not the key in mediating the DR response. We hypothesize that dilp6 expression may take over expression of dilp2, -3 and -5 in the d235∆ flies, but not sufficient to maintain the same lifespan and reproduction on every food type.