Transcriptional Characteristics of Activated Macrophages

Macrophages are key players in human innate immunity that protect the organism from pathologic agents, including infection and malignant cells. The spectrum of their functions includes initiation and maintaining of inflammation, cleaning of pathogens and cell debris, as well as inflammation resolution and tissue remodeling and repair. Such a wide spectrum is reflected by the great variety of macrophage phenotypes based on the activation of distinct transcription patterns in response to different stimuli. Studying this complexity requires an integrated approach, such as transcriptome studies. For many genes, the exact role in macrophage biology remains unknown, although clear associations with pro- or anti-inflammatory macrophage polarization could be demonstrated. These findings reveal the novel directions for future research. In this review, we describe the known mechanisms of macrophage polarization and the new insights available from transcriptome studies.