Early injury responses to nutrient treatment in adult Drosophila limb

It was previously observed that partial regrowth can be induced to begin in adult Drosophila limb by modulating nutrients. In this work, to further investigate the observation, we characterized the early cellular and tissue-level processes that are promoted by nutrient treatment after injury. We find that response to nutrient treatment can be readily identified within hours, by alteration in wound healing. Subsequently, at day-scale, dramatic reversal of large-scale tissue loss occurs in treated flies. Finally, at week-scale, tissue remodeling begins and a dome-shaped protrusion forms at the injury site. Performing single-nucleus RNA sequencing at this stage, we find widespread transcriptional modulations across cell types. Distinct muscle and epithelial cell types emerge that are enriched in mitotic and morphogenetic genes, including those associated with regeneration in larval tissues. The tissue-, cell-, and gene-level processes characterized here provide a framework for the previously observed partial limb growth and for further investigating the suggestion of regeneration induction in adult Drosophila by nutrient treatment.