Open Access

Sara Elhag, Christopher Stremmel, Annette Zehrer, Josefine Plocke, Roman Hennel, Michaela Keuper, Clarissa Knabe, Julia Winterhalter, Vanessa Gölling, Lukas Tomas, Tobias Weinberger, Maximilian Fischer, Lulu Liu, Franziska Wagner, Michael Lorenz, Konstantin Stark, Hans Häcker, Marc Schmidt-Supprian, Uwe Völker, Martin Jastroch, Kirsten Lauber, Tobias Straub, Barbara Walzog, Elke Hammer, Christian Schulz

• Background: Tissue-resident macrophages have mixed developmental origins. They derive in variable extent from yolk sac (YS) hematopoiesis during embryonic development. Bone marrow (BM) hematopoietic progenitors give rise to tissue macrophages in postnatal life, and their contribution increases upon organ injury. Since the phenotype and functions of macrophages are modulated by the tissue of residence, the impact of their origin and developmental paths has remained incompletely understood. Methods: In order to decipher cell-intrinsic macrophage programs, we immortalized hematopoietic progenitors from YS and BM using conditional HoxB8, and carried out an in-depth functional and molecular analysis of differentiated macrophages. Results: While YS and BM macrophages demonstrate close similarities in terms of cellular growth, differentiation, cell death susceptibility and phagocytic properties, they display differences in cell metabolism, expression of inflammatory markers and inflammasome activation. Reduced abundance of PYCARD (ASC) and CASPASE-1 proteins in YS macrophages abrogated interleukin-1β production in response to canonical and non-canonical inflammasome activation. Conclusions: Macrophage ontogeny is associated with distinct cellular programs and immune response. Our findings contribute to the understanding of the regulation and programming of macrophage functions.