Marco Prinz

1. Microglia origin, fate and functionMicroglia are tissue-resident macrophages in the central nervous system (CNS). They belong to a group of mononuclear phagocytes that comprises peripheral tissue macrophages, CNS-associated macrophages, dendritic cells and monocyte-derived cells (Prinz & Priller 2014). As such they are critical effectors and regulators of changes in CNS homeostasis during development and in health and disease (Prinz et al. 2011). All mononuclear cells originate from hematopoietic stem cells (HSCs) and develop along distinct differentiation pathways in response to endogenous and environmental cues. It was assumed that bone marrow-derived monocytes, a subgroup of leukocytes, circulate in the blood and enter the tissues (where they differentiate into tissue-resident macrophages) in non-pathological conditions and during inflammation. However, this view has been markedly changed in recent years as a result of the discovery of new subtypes of mononuclear phagocytes and their distinct roles in CNS disorders. In the past our lab could identify the peripheral bone marrow-derived precursor that gives rise to microglia during diseases (Mildner et al. 2007). Recently, our lab was able to identify the microglia precursor in the yolk sac and could further decipher the transcriptional program that is required for the development of erythromyeloid precursors to mature microglia during development (Kierdorf et al. 2013). Furthermore, our lab established the first inducible microglia-specific Cre mouse for gene targeting in those cells (Goldmann, Wieghofer et al. 20013). In sum, our research revealed a pivotal role of microglia for the CNS during health and disease.Figure: IMARIS-based three-dimensional reconstruction of a microglia cell (from Goldmann, Wieghofer et al. 2013).