Murine <i>Ex Vivo</i> Cultured Alveolar Macrophages Provide a Novel Tool to Study Tissue-Resident Macrophage Behavior and Function
Anna-Dorothea Gorki, Dörte Symmank, Sophie Zahalka, Karin Lakovits, Anastasiya Hladik, Brigitte Langer, Barbara Maurer, Veronika Sexl, Renate Kain, Sylvia Knapp
Abstract
Abstract Tissue-resident macrophages are of vital importance as they preserve tissue homeostasis in all mammalian organs. Nevertheless, appropriate cell culture models are still limited. Here, we propose a novel culture model to study and expand murine primary alveolar macrophages (AMs), the tissue-resident macrophages of the lung, in vitro over several months. By providing a combination of granulocyte-macrophage colony-stimulating factor, TGFβ, and the PPARγ activator rosiglitazone, we maintain and expand mouse ex vivo cultured AMs (mexAMs) over several months. MexAMs maintain typical morphologic features and stably express primary AM surface markers throughout in vitro culture. They respond to microbial ligands and exhibit an AM-like transcriptional profile, including the expression of AM-specific transcription factors. Furthermore, when transferred into AM-deficient mice, mexAMs efficiently engraft in the lung and fulfill key macrophage functions, leading to a significantly reduced surfactant load in those mice. Altogether, mexAMs provide a novel, simple, and versatile tool to study AM behavior in homeostasis and disease settings.