Cambridge Institute of Therapeutic Immunology and Infectious Disease (CITIID), Cambridge, UK; Department of Medicine, University of Cambridge, Cambridge, UK; Corresponding author
Na Zhao
University of Oxford, Oxford, UK
Petra Mlcochova
Cambridge Institute of Therapeutic Immunology and Infectious Disease (CITIID), Cambridge, UK; Department of Medicine, University of Cambridge, Cambridge, UK
Isabella A.T.M. Ferreira
Cambridge Institute of Therapeutic Immunology and Infectious Disease (CITIID), Cambridge, UK; Department of Medicine, University of Cambridge, Cambridge, UK
Brian M. Ortmann
Cambridge Institute of Therapeutic Immunology and Infectious Disease (CITIID), Cambridge, UK; Department of Medicine, University of Cambridge, Cambridge, UK
Tanja Davis
University of Oxford, Oxford, UK
Niek Wit
Cambridge Institute of Therapeutic Immunology and Infectious Disease (CITIID), Cambridge, UK; Department of Medicine, University of Cambridge, Cambridge, UK
Jan Rehwinkel
University of Oxford, Oxford, UK
Simon Cook
Babraham Institute, Cambridge, UK
Patrick H. Maxwell
School of Clinical Medicine, University of Cambridge, Cambridge, UK
James A. Nathan
Cambridge Institute of Therapeutic Immunology and Infectious Disease (CITIID), Cambridge, UK; Department of Medicine, University of Cambridge, Cambridge, UK
Ravindra K. Gupta
Cambridge Institute of Therapeutic Immunology and Infectious Disease (CITIID), Cambridge, UK; Department of Medicine, University of Cambridge, Cambridge, UK; Africa Health Research Institute, Durban, KwaZulu Natal, South Africa; Corresponding author
Summary: Low-oxygen conditions (hypoxia) have been associated primarily with cell-cycle arrest in dividing cells. Macrophages are typically quiescent in G0 but can proliferate in response to tissue signals. Here we show that hypoxia (1% oxygen tension) results in reversible entry into the cell cycle in macrophages. Cell cycle progression is largely limited to G0-G1/S phase transition with little progression to G2/M. This cell cycle transitioning is triggered by an HIF2α-directed transcriptional program. The response is accompanied by increased expression of cell-cycle-associated proteins, including CDK1, which is known to phosphorylate SAMHD1 at T592 and thereby regulate antiviral activity. Prolyl hydroxylase (PHD) inhibitors are able to recapitulate HIF2α-dependent cell cycle entry in macrophages. Finally, tumor-associated macrophages (TAMs) in lung cancers exhibit transcriptomic profiles representing responses to low oxygen and cell cycle progression at the single-cell level. These findings have implications for inflammation and tumor progression/metastasis where low-oxygen environments are common.
