Cytoneme-mediated signalling coordinates the development of glial cells and neurons in the Drosophila eye

Effective cell communication is essential for the development and maintenance of the nervous system, where neurons and glial cells must interact closely. While cytoneme-mediated signalling is well-documented in various biological contexts, its role in coordinating neuron-glia development remains poorly understood. In this study, we investigated the function of cytonemes in neuron-glia coordination using the Drosophila eye imaginal disc as a model. This is a well-established system for examining the orchestrated development of glial and neuronal cells. Our results reveal that glial cells produce two distinct types of cytonemes based on their spatial orientation: one set extends toward nascent photoreceptors, while the other targets the morphogenetic furrow (MF). We have characterised the dynamics of glial cytonemes and demonstrated that disrupting these structures has a significant impact on glial cell migration and differentiation. This highlights the critical role of cytoneme-mediated signalling in regulating glial behaviour. Our findings also demonstrate that cytoneme function is essential for activating the Hedgehog (Hh) pathway in glial cells, with Hh ligand produced by photoreceptors. This pathway is necessary for glial differentiation, uncovering a previously unrecognised role for Hh signalling in this process. Overall, our results suggest that cytoneme-mediated Hh signalling is key to coordinating the development of both glial and neuronal populations.