DNA damage signaling and polyploid macrophages in chronic inflammation.

Whole genome duplications, an important step in cancer development, also occur in the macrophage lineage in disease: large multinucleated macrophages found within compact, ordered aggregates of immune cells, called granulomas, are a well-known histologic entity. Very recent work suggests that granuloma macrophages remarkably acquire epithelial cell features and the genotoxic stress response instructs granuloma macrophage genome duplications, suggesting that granuloma macrophages and pre-malignant epithelial cells may share common mechanisms of adaptation to chronic genotoxic stress. Exploring these mechanisms is key for a better understanding of the pathogenesis of chronic inflammatory diseases. Here we review the mechanisms of macrophage polyploidization, the role of DNA damage signaling in this process and the function of polyploid macrophages, with a focus on chronic inflammation.