RT Journal Article SR Electronic T1 Murine ex vivo cultured alveolar macrophages provide a novel tool to study tissue-resident macrophage behavior and function JF bioRxiv FD Cold Spring Harbor Laboratory SP 2021.02.11.430791 DO 10.1101/2021.02.11.430791 A1 A.-D. Gorki A1 D. Symmank A1 S. Zahalka A1 K. Lakovits A1 A. Hladik A1 B. Langer A1 B. Maurer A1 V. Sexl A1 R. Kain A1 S. Knapp YR 2021 UL http://biorxiv.org/content/early/2021/02/11/2021.02.11.430791.abstract AB 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 GM-CSF, TGFβ and the PPARγ activator rosiglitazone, we maintain and expand mouse ex vivo cultured AMs, short 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.KEYPOINTSA novel method to culture and expand primary alveolar macrophages over several months ex vivoMurine ex vivo cultured alveolar macrophages (mexAMs) restore lung function in a murine pulmonary alveolar proteinosis modelCompeting Interest StatementThe authors have declared no competing interest.