An improved organotypic cell culture system to study tissue-resident macrophages ex vivo
Philipp Aktories, Philippe Petry, Paulo Glatz, Geoffroy Andrieux, Alexander Oschwald, Hannah Botterer, Oliver Gorka, Daniel Erny, Melanie Boerries, Philipp Henneke, Olaf Groß, Marco Prinz, Katrin Kierdorf
Abstract
Tissue-resident macrophages (TRMs) perform organ-specific functions that are dependent on factors such as hematopoietic origin, local environment, and biological influences. A diverse range of in vitro culture systems have been developed to decipher TRM functions, including bone marrow-derived macrophages (BMDMs), induced pluripotent stem cell (iPSC)-derived TRMs, or immortalized cell lines. However, despite the usefulness of such systems, there are notable limitations. Attempts to culture primary macrophages often require purification of cells and lack a high cell yield and consistent phenotype. Here, we aimed to address these limitations by establishing an organotypic primary cell culture protocol. We obtained long-term monocultures of macrophages derived from distinct organs without prior purification using specific growth factors and tissue normoxic conditions that largely conserved a TRM-like identity in vitro. Thus, this organotypic system offers an ideal screening platform for primary macrophages from different organs that can be used for a wide range of assays and readouts.