Long-term culture-expanded alveolar macrophages restore their full epigenetic identity after transfer in vivo.

Nature immunology 2022 Mar

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Alveolar macrophages (AMs) are lung tissue-resident macrophages that can be expanded in culture, but it is unknown to what extent culture affects their in vivo identity. Here we show that mouse long-term ex vivo expanded AMs (exAMs) maintained a core AM gene expression program, but showed culture adaptations related to adhesion, metabolism and proliferation. Upon transplantation into the lung, exAMs reacquired full transcriptional and epigenetic AM identity, even after several months in culture and could self-maintain long-term in the alveolar niche. Changes in open chromatin regions observed in culture were fully reversible in transplanted exAMs and resulted in a gene expression profile indistinguishable from resident AMs. Our results indicate that long-term proliferation of AMs in culture did not compromise cellular identity in vivo. The robustness of exAM identity provides new opportunities for mechanistic analysis and highlights the therapeutic potential of exAMs. © 2022. The Author(s), under exclusive licence to Springer Nature America, Inc.

Citation

Sethuraman Subramanian, Clara Jana-Lui Busch, Kaaweh Molawi, Laufey Geirsdottir, Julien Maurizio, Stephanie Vargas Aguilar, Hassiba Belahbib, Gregory Gimenez, Ridzky Anis Advent Yuda, Michaela Burkon, Jérémy Favret, Sara Gholamhosseinian Najjar, Bérengère de Laval, Prashanth Kumar Kandalla, Sandrine Sarrazin, Lena Alexopoulou, Michael H Sieweke. Long-term culture-expanded alveolar macrophages restore their full epigenetic identity after transfer in vivo. Nature immunology. 2022 Mar;23(3):458-468