From Monocytes to M1/M2 Macrophages: Phenotypical vs. Functional Differentiation

By P. Italiani, D. Boraschi. Frontiers in Immunology, 2014

1,955 citations recorded by the source corpus.

Studies on monocyte and macrophage biology and differentiation have revealed the pleiotropic activities of these cells. Macrophages are tissue sentinels that maintain tissue integrity by eliminating/repairing damaged cells and matrices. In this M2-like mode, they can also promote tumor growth. Conversely, M1-like macrophages are key effector cells for the elimination of pathogens, virally infected, and cancer cells. Macrophage differentiation from monocytes occurs in the tissue in concomitance with the acquisition of a functional phenotype that depends on microenvironmental signals, thereby accounting for the many and apparently opposed macrophage functions. Many questions arise. When monocytes differentiate into macrophages in a tissue (concomitantly adopting a specific functional program, M1 or M2), do they all die during the inflammatory reaction, or do some of them survive? Do those that survive become quiescent tissue macrophages, able to react as naïve cells to a new challenge? Or, do monocyte-derived tissue macrophages conserve a “memory” of their past inflammatory activation? This review will address some of these important questions under the general framework of the role of monocytes and macrophages in the initiation, development, resolution, and chronicization of inflammation.

Subfields: Immunology

View Paper: https://www.semanticscholar.org/paper/7a2a03bc13c61be3228deea7c1d46d0211ed7c56

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Citations in the corpus

Much More than M1 and M2 Macrophages, There are also CD169+ and TCR+ Macrophages (2015, background): “Italiani and Boraschi have recently reviewed human and murine monocyte subsets and the fate of monocyte/macrophage populations and functions in the main body tissues during steady state and inflammatory conditions (15).”
The Role of Macrophages in Acute and Chronic Wound Healing and Interventions to Promote Pro-wound Healing Phenotypes (2018, background): “CX3CR1-dependent pathways, respectively (Italiani and Boraschi, 2014; Ogle et al., 2016).”
Platelet-Rich Plasma: New Performance Understandings and Therapeutic Considerations in 2020 (2020, background): “Furthermore, T lymphocyte-derived cytokines (interferon-γ [IFN-γ ] and interleukin-4 [IL-4]) strengthen macrophage polarization [86].”
Pathophysiology of Atherosclerosis (2022, background): “Once in the intima, monocytes are differentiated into macrophages that can be polarized to the M1 (pro-inflammatory) or M2 (anti-inflammatory) phenotype [141,142].”
Progress in tumor-associated macrophage (TAM)-targeted therapeutics (2017, positive): “Based on pro-inflammatory and antiinflammatory functions of macrophages under different stimuli, a broad classification has been proposed to generalize macrophages as classically activated M1 (pro-inflammatory, activated by LPS or interferon gamma (IFNγ)) or alternatively activated M2 (antiinflammat”