Subsets, Origin, Function, and Role of Pulmonary Macrophages in Pulmonary Diseases
JIAO Juntao1 , GAO Jiayu2 , WANG Kefan3 , XIAO Yang3 , JING Ruicong1 , SHAO Dongxu1 , ZHANG Ni4 *
Pulmonary macrophages are innate immune cells with significant heterogeneity in origin, activation, and function, playing crucial roles in host defense, maintenance of immune homeostasis, and immunoregulation. They consist of AMs (alveolar macrophages) and pulmonary IMs (interstitial macrophages). Recent studies indicate that AMs originate from the yolk sac and maintain themselves through self-renewal under steady-state conditions. However, during disease states, AMs can be replaced by bone marrow-derived monocytes. Based on their origin, AMs can be classified into TR-AMs (tissue-resident alveolar macrophages) and MO-AMs (monocyte-derived alveolar macrophages). In contrast, IMs have a mixed origin from both yolk sac and postnatal bone marrow-derived monocytes, and their renewal typically relies on bone marrow-derived monocytes. Therefore, this article integrates the latest research advances to summarize pulmonary macrophage subsets across diverse origins, subtypes, anatomical locations, and functions, aiming to elucidate their roles and mechanisms in pulmonary diseases and provide a theoretical basis for developing therapies targeting specific macrophage subsets.
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