Glial phagocytosis in developing and mature Drosophila CNS: tight regulation for a healthy brain

Glia are heterogeneous and multitasking cell type in the nervous system that supports neuronal function. One of the main glial tasks is removal of unneeded and potentially harmful material through phagocytosis. Glial phagocytosis is highly conserved throughout evolution, which makes genetic model organisms such as Drosophila of great value for investigating its molecular mechanisms. This mini review will focus on recent findings regarding the complex role of glial phagocytosis in Drosophila CNS during development as well as at the adult stage. We will summarize the current knowledge regarding partially redundant and overlapping signaling pathways underlying clearance of different targets in normal and diseased brain. In addition, we will highlight a recently emerged concept of glia-driven neurodegeneration that exposes the potentially harmful role of phagocytic glia. Studies on Drosophila glia provide new insights, which open new directions in glial cell biology with potential impact on healthy and diseased brain function.