Understanding the Mysterious M2 Macrophage through Activation Markers and Effector Mechanisms

• Published in: Mediators of Inflammation Vol. 2015; no. 2015; pp. 305 - 320-428
• Main Author: Roszer, Tamas
• Format: Journal Article
• Language: English
• Published: Cairo, Egypt Hindawi Limiteds 01.01.2015; Hindawi Publishing Corporation; John Wiley & Sons, Inc; Wiley
• Subjects: Bacterial infections; Biological markers; Biomedical research; Cytokines; Endocrinology; Extracellular matrix; Health aspects; Humans; Macrophage Activation - physiology; Macrophages; Macrophages - metabolism; Metabolic disorders; Neurosecretory Systems - metabolism; Parasites; Review; Tumor necrosis factor-TNF; Vascular endothelial growth factor; Wound healing
• ISSN: 0962-9351; 1466-1861; 1466-1861
• DOI: 10.1155/2015/816460

The alternatively activated or M2 macrophages are immune cells with high phenotypic heterogeneity and are governing functions at the interface of immunity, tissue homeostasis, metabolism, and endocrine signaling. Today the M2 macrophages are identified based on the expression pattern of a set of M2 markers. These markers are transmembrane glycoproteins, scavenger receptors, enzymes, growth factors, hormones, cytokines, and cytokine receptors with diverse and often yet unexplored functions. This review discusses whether these M2 markers can be reliably used to identify M2 macrophages and define their functional subdivisions. Also, it provides an update on the novel signals of the tissue environment and the neuroendocrine system which shape the M2 activation. The possible evolutionary roots of the M2 macrophage functions are also discussed.