While M1 macrophages are highly pro-inflammatory and microbicidal,M2 macrophages and the related tumor associated macrophages (TAMs) regulate tissue remodeling and anglogenesis and can display immunomodulatory activity.In July issue of Cell Research,Zhang et al.show that ROS production,critical for the activation and functions of M1 macrophages,is necessary for the differentiation of M2 macrophages and TAMs,and that antioxidant therapy blocks TAM differentiation and tumorigenesis in mouse models of cancer.
Macrophages are key orchestrators in both the initiation and resolution stages of inflammation,and function as sentinel cells that maintain homeostasis and protect against infection.