Melanie Greter

Melanie Greter is a Swiss neuroimmunologist and a Swiss National Science Foundation Professor in the Institute of Experimental Immunology at the University of Zurich. Greter explores the ontogeny and function of microglia and border-associated macrophages of the central nervous system to understand how they maintain homeostasis and contribute to brain-related diseases.

Early life and education After completing her undergraduate degree, Greter pursued a master's degree in biology at the University of Zurich in Switzerland. She completed her Master's thesis at the Institute of Neuropathology at the University Hospital Zurich. Greter joined the lab of Burkhard Becher who had just recently started his lab at the University of Zurich in the Department of Neurology. In the Burkhard Lab, Greter explored the role of cytokines in driving inflammation in different disease models. One of the first projects that Greter worked on led to a paper in Nature Medicine where the team found that ablating microglia inhibited the development and maintenance of inflammation in the central nervous system in experimental autoimmune encephalomyelitis. Shortly after, Greter published a first author publication in Nature Medicine showing that a unique population of vessel-associated dendritic cells in the brain act as antigen-presenting cells and mediate the activation and entry of reactive T cells into the brain to initiate inflammation and disease development. Towards the end of Greter's PhD, she wrote a review paper with Becher discussing the current knowledge of how autoreactive T cells enter the brain to initiate inflammation and disease progression. Greter made this discovery using alymphoplastic mice which lack lymph nodes due to a specific genetic mutation. Greter also studied other macrophage-like cells, specifically microglia such that in 2010, Greter became second author on a seminal paper in the field of neuroimmunology and glial biology. Greter and her colleagues in the Merad Lab found that microglia, the brain's resident macrophages, derive from primitive macrophages in the fetal yolk sac.

Career and research In 2011, Greter moved back to Switzerland to work at her alma mater, the University of Zurich. In 2012, she published a first author paper in Immunity highlighting the striking finding that IL-34, the alternative ligand of colony stimulating factor-1 receptor, is crucial for the repopulation of langerhans cells in the skin and for the maintenance, but not the development of, microglia in the brain.

In 2013, Greter was offered an opportunity to start her own lab at the University of Zurich. Greter was one of two neuroscientists at the University of Zurich to receive the SNSF Starting Grant in 2013 providing 1.5 million dollars in funding to support her goals of targeting specific cells within the mononuclear phagocyte system despite their immense heterogeneity.

Since becoming a professor, Greter has remained a source of critical knowledge in the microglia community. Her work not helps to elucidate the distinct ontogeny and functions of microglia from other myeloid cells, but she has also written articles discussing microglia versus myeloid nomenclature to keep the community united by common terms. She has also discussed the specificity and efficacy of Cre/loxP systems for use in probing biological systems so that the field can stay up to date with the status of current tools with which to probe cells in the immune and nervous systems.

Greter's first paper as a professor was published in 2016, just three years after starting her lab. They further used the Sall1 locus for microglia-specific gene targeting and they found that inactivating the Sall1 locus led microglia to transition from a resting state to a pro-inflammatory phagocytic state suggesting the critical role Sall1 plays in maintaining microglial identity and physiology in vivo. Fascinatingly, these two cellular populations have distinct progenitors in the fetal yolk sac suggesting that they are actual distinct in very early stages of development. as well as an International Advisory Board Member of the International Society of Neuroimmunology. 2013 Swiss National Science Foundation Starting Grant

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