Resident tissue macrophages are found in nearly all metazoan organisms and are distributed throughout most tissues in the body. In vertebrates, it was recently shown that most resident macrophage populations are long-lived cell populations of embryonic origin with a slow endogenous turn over. Similarly in adult Drosophila, tissue macrophages are long-lived cells with embryonic or larval origin, however these cells do not show any turnover or proliferation. In many tissues, macrophages offer a first line of defense upon injury or infection by secretion of a wide range of inflammatory molecules as well as the efficient phagocytosis of cell debris or pathogens. Beside their role in infection and inflammation, tissue macrophages also serve a plethora of physiological functions to maintain tissue homeostasis in their host organs. Disruption of physiological macrophage development, maturation or network formation within the tissues can have detrimental effects on the organs function and result in severe pathologies. In our group, we are interested to understand the intrinsic and extrinsic factors which control the establishment of a healthy and homeostatic macrophage network within adult tissues. Besides studying macrophages in the mouse model, we take advantage of the fruit fly Drosophila melanogaster, as a model to screen for potential candidates involved in physiological macrophage function. In association with the SFB/TRR 167, we are interested to better characterize how the physiological network of resident tissue macrophages in the CNS is established. CNS macrophages are a highly specialized and adapted macrophage population and already mild changes in their physiological behaviour or development can have detrimental consequences for the neuronal network. As a newly started lab, we hope to take advantage from the scientific and collaborative network of this powerful initiative. In collaboration with various projects within the SFB/TRR 167, we hope to better understand which factors propagate and facilitate CNS macrophage network formation and physiological function.