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Frontiers in Immunology 2021This mini-review summarizes the current evidence for the role of macrophage activation and polarization in inflammation and immune response pertinent to interstitial... (Review)
Review
This mini-review summarizes the current evidence for the role of macrophage activation and polarization in inflammation and immune response pertinent to interstitial lung disease, specifically pulmonary fibrosis. In the fibrosing lung, the production and function of inflammatory and fibrogenic mediators involved in the disease development have been reported to be regulated by the effects of polarized M1/M2 macrophage populations. The M1 and M2 macrophage phenotypes were suggested to correspond with the pro-inflammatory and pro-fibrogenic signatures, respectively. These responses towards tissue injury followed by the development and progression of lung fibrosis are further regulated by macrophage-derived microRNAs (miRNAs). Besides cellular miRNAs, extracellular exosomal-miRNAs derived from M2 macrophages have also been proposed to promote the progression of pulmonary fibrosis. In a future perspective, harnessing the noncoding miRNAs with a key role in the macrophage polarization is, therefore, suggested as a promising therapeutic strategy for this debilitating disease.
Topics: Animals; Biomarkers; Cell Plasticity; Cytokines; Disease Susceptibility; Exosomes; Gene Expression Regulation; Humans; Inflammation Mediators; Macrophage Activation; Macrophages; MicroRNAs; Models, Biological; Pulmonary Fibrosis
PubMed: 34489932
DOI: 10.3389/fimmu.2021.678457 -
Immunity May 2010The concept of an alternative pathway of macrophage activation has stimulated interest in its definition, mechanism, and functional significance in homeostasis and... (Review)
Review
The concept of an alternative pathway of macrophage activation has stimulated interest in its definition, mechanism, and functional significance in homeostasis and disease. We assess recent research in this field, argue for a restricted definition, and explore pathways by which the T helper 2 (Th2) cell cytokines interleukin-4 (IL-4) and IL-13 mediate their effects on macrophage cell biology, their biosynthesis, and responses to a normal and pathological microenvironment. The stage is now set to gain deeper insights into the role of alternatively activated macrophages in immunobiology.
Topics: Animals; Cytokines; Humans; Macrophage Activation; Macrophages; Models, Biological; Neoplasms; Receptors, Interleukin; Signal Transduction
PubMed: 20510870
DOI: 10.1016/j.immuni.2010.05.007 -
Frontiers in Immunology 2021Macrophages can be polarized into classically activated macrophages (M1) and alternatively activated macrophages (M2) in the immune system, performing pro-inflammatory... (Comparative Study)
Comparative Study
Macrophages can be polarized into classically activated macrophages (M1) and alternatively activated macrophages (M2) in the immune system, performing pro-inflammatory and anti-inflammatory functions, respectively. Human THP-1 and mouse RAW264.7 cell line models have been widely used in various macrophage-associated studies, while the similarities and differences in protein expression profiles between the two macrophage models are still largely unclear. In this study, the protein expression profiles of M1 and M2 phenotypes from both THP-1 and RAW264.7 macrophages were systematically investigated using mass spectrometry-based proteomics. By quantitatively analyzing more than 5,000 proteins among different types of macrophages (M0, M1 and M2) from both cell lines, we identified a list of proteins that were uniquely up-regulated in each macrophage type and further confirmed 43 proteins that were commonly up-regulated in M1 macrophages of both cell lines. These results revealed considerable divergences of each polarization type between THP-1 and RAW264.7 macrophages. Moreover, the mRNA and protein expression of CMPK2, RSAD2, DDX58, and DHX58 were strongly up-regulated in M1 macrophages for both macrophage models. These data can serve as important resources for further studies of macrophage-associated diseases in experimental pathology using human and mouse cell line models.
Topics: Animals; Humans; Macrophage Activation; Macrophages; Mice; Proteomics; RAW 264.7 Cells; THP-1 Cells
PubMed: 34267761
DOI: 10.3389/fimmu.2021.700009 -
Mediators of Inflammation 2015The alternatively activated or M2 macrophages are immune cells with high phenotypic heterogeneity and are governing functions at the interface of immunity, tissue... (Review)
Review
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.
Topics: Humans; Macrophage Activation; Macrophages; Neurosecretory Systems
PubMed: 26089604
DOI: 10.1155/2015/816460 -
Frontiers in Immunology 2021Metformin is one of the most widely prescribed hypoglycemic drugs and has the potential to treat many diseases. More and more evidence shows that metformin can regulate... (Review)
Review
Metformin is one of the most widely prescribed hypoglycemic drugs and has the potential to treat many diseases. More and more evidence shows that metformin can regulate the function of macrophages in atherosclerosis, including reducing the differentiation of monocytes and inhibiting the inflammation, oxidative stress, polarization, foam cell formation and apoptosis of macrophages. The mechanisms by which metformin regulates the function of macrophages include AMPK, AMPK independent targets, NF-κB, ABCG5/8, Sirt1, FOXO1/FABP4 and HMGB1. On the basis of summarizing these studies, we further discussed the future research directions of metformin: single-cell RNA sequencing, neutrophil extracellular traps (NETs), epigenetic modification, and metformin-based combination drugs. In short, macrophages play an important role in a variety of diseases, and improving macrophage dysfunction may be an important mechanism for metformin to expand its pleiotropic pharmacological profile. In addition, the combination of metformin with other drugs that improve the function of macrophages (such as SGLT2 inhibitors, statins and IL-1β inhibitors/monoclonal antibodies) may further enhance the pleiotropic therapeutic potential of metformin in conditions such as atherosclerosis, obesity, cancer, dementia and aging.
Topics: Animals; Atherosclerosis; Biomarkers; Cardiometabolic Risk Factors; Cell Plasticity; Diabetes Complications; Diabetes Mellitus; Disease Susceptibility; Energy Metabolism; Humans; Macrophage Activation; Macrophages; Metformin; Signal Transduction
PubMed: 34163481
DOI: 10.3389/fimmu.2021.682853 -
Immunology and Cell Biology Mar 2019Macrophages are critically involved in wound healing, from dampening inflammation to clearing cell debris and coordinating tissue repair. Within the wound, the... (Review)
Review
Macrophages are critically involved in wound healing, from dampening inflammation to clearing cell debris and coordinating tissue repair. Within the wound, the complexity of macrophage function is increasingly recognized, with adverse outcomes when macrophages are inappropriately activated, such as in fibrosis or chronic non-healing wounds. Recent advances in in vivo and translational wound models, macrophage-specific deletions and new technologies to distinguish macrophage subsets, have uncovered the vast spectrum of macrophage activation and effector functions. Here, we summarize the main players in wound-healing macrophage activation and function, including cytokines, apoptotic cells, nucleotides and mechanical stimuli. We highlight recent studies demonstrating cooperation between these factors for optimal wound healing. Next, we describe recent technologies such as cell tracking and single-cell RNA-seq, which have uncovered remarkable plasticity and heterogeneity in blood-derived or tissue-resident macrophages and discuss the implications for wound healing. Lastly, we evaluate macrophage dysfunction in aberrant wound healing that occurs in aging, diabetes and fibrosis. A better understanding of the longevity and plasticity of wound-healing macrophages, and identification of unique macrophage subsets or specific effector molecules in wound healing, would shed light on the therapeutic potential of manipulating macrophage function for optimal wound healing.
Topics: Animals; Apoptosis; Biomarkers; Cell Plasticity; Cytokines; Disease Susceptibility; Fibrosis; Gene Expression Regulation; Humans; Inflammation Mediators; Macrophage Activation; Macrophages; Signal Transduction; Wound Healing
PubMed: 30746824
DOI: 10.1111/imcb.12236 -
Frontiers in Immunology 2021Persistent hyper-inflammation is a distinguishing pathophysiological characteristic of chronic wounds, and macrophage malfunction is considered as a major contributor... (Review)
Review
Persistent hyper-inflammation is a distinguishing pathophysiological characteristic of chronic wounds, and macrophage malfunction is considered as a major contributor thereof. In this review, we describe the origin and heterogeneity of macrophages during wound healing, and compare macrophage function in healing and non-healing wounds. We consider extrinsic and intrinsic factors driving wound macrophage dysregulation, and review systemic and topical therapeutic approaches for the restoration of macrophage response. Multidimensional analysis is highlighted through the integration of various high-throughput technologies, used to assess the diversity and activation states as well as cellular communication of macrophages in healing and non-healing wound. This research fills the gaps in current literature and provides the promising therapeutic interventions for chronic wounds.
Topics: Animals; Biomarkers; Chronic Disease; Humans; Inflammation; Macrophage Activation; Macrophages; Regeneration; Wound Healing
PubMed: 34220830
DOI: 10.3389/fimmu.2021.681710 -
Immunobiology Sep 2014Macrophages form a heterogeneous cell population displaying multiple functions, and can be polarized into pro- (M1) or anti-inflammatory (M2) macrophages, by...
Macrophages form a heterogeneous cell population displaying multiple functions, and can be polarized into pro- (M1) or anti-inflammatory (M2) macrophages, by environmental factors. Their activation status reflects a beneficial or detrimental role in various diseases. Currently several in vitro maturation and activation protocols are used to induce an M1 or M2 phenotype. Here, the impact of different maturation factors (NHS, M-CSF, or GM-CSF) and activation methods (IFN-γ/LPS, IL-4, dexamethason, IL-10) on the macrophage phenotype was determined. Regarding macrophage morphology, pro-inflammatory (M1) activation stimulated cell elongation, and anti-inflammatory (M2) activation induced a circular appearance. Activation with pro-inflammatory mediators led to increased CD40 and CD64 expression, whereas activation with anti-inflammatory factors resulted in increased levels of MR and CD163. Production of pro-inflammatory cytokines was induced by activation with IFN-γ/LPS, and TGF-β production was enhanced by the maturation factors M-CSF and GM-CSF. Our data demonstrate that macrophage marker expression and cytokine production in vitro is highly dependent on both maturation and activation methods. In vivo macrophage activation is far more complex, since a plethora of stimuli are present. Hence, defining the macrophage activation status ex vivo on a limited number of markers could be indecisive. From this study we conclude that maturation with M-CSF or GM-CSF induces a moderate anti- or pro-inflammatory state respectively, compared to maturation with NHS. CD40 and CD64 are the most distinctive makers for human M1 and CD163 and MR for M2 macrophage activation and therefore can be helpful in determining the activation status of human macrophages ex vivo.
Topics: Cell Differentiation; Cells, Cultured; Granulocyte-Macrophage Colony-Stimulating Factor; Humans; Immunologic Techniques; In Vitro Techniques; Macrophage Activation; Macrophage Colony-Stimulating Factor; Macrophages; Serum
PubMed: 24916404
DOI: 10.1016/j.imbio.2014.05.002 -
Nature Reviews. Immunology Sep 2018IFNγ is a cytokine with important roles in tissue homeostasis, immune and inflammatory responses and tumour immunosurveillance. Signalling by the IFNγ receptor... (Review)
Review
IFNγ is a cytokine with important roles in tissue homeostasis, immune and inflammatory responses and tumour immunosurveillance. Signalling by the IFNγ receptor activates the Janus kinase (JAK)-signal transducer and activator of transcription 1 (STAT1) pathway to induce the expression of classical interferon-stimulated genes that have key immune effector functions. This Review focuses on recent advances in our understanding of the transcriptional, chromatin-based and metabolic mechanisms that underlie IFNγ-mediated polarization of macrophages to an 'M1-like' state, which is characterized by increased pro-inflammatory activity and macrophage resistance to tolerogenic and anti-inflammatory factors. In addition, I describe the newly discovered effects of IFNγ on other leukocytes, vascular cells, adipose tissue cells, neurons and tumour cells that have important implications for autoimmunity, metabolic diseases, atherosclerosis, neurological diseases and immune checkpoint blockade cancer therapy.
Topics: Adaptive Immunity; Animals; Epigenesis, Genetic; Humans; Immune Tolerance; Immunotherapy; Inflammation; Interferon-gamma; Macrophage Activation; Macrophages; Metabolic Diseases; Models, Immunological; Neoplasms; Signal Transduction
PubMed: 29921905
DOI: 10.1038/s41577-018-0029-z -
Frontiers in Immunology 2022Macrophages are essential innate immune cells that contribute to host defense during infection. An important feature of macrophages is their ability to respond to... (Review)
Review
Macrophages are essential innate immune cells that contribute to host defense during infection. An important feature of macrophages is their ability to respond to extracellular cues and to adopt different phenotypes and functions in response to these stimuli. The evidence accumulated in the last decade has highlighted the crucial role of metabolic reprogramming during macrophage activation in infectious context. Thus, understanding and manipulation of macrophage immunometabolism during infection could be of interest to develop therapeutic strategies. In this review, we focus on 5 major metabolic pathways including glycolysis, pentose phosphate pathway, fatty acid oxidation and synthesis, tricarboxylic acid cycle and amino acid metabolism and discuss how they sustain and regulate macrophage immune function in response to parasitic, bacterial and viral infections as well as trained immunity. At the end, we assess whether some drugs including those used in clinic and in development can target macrophage immunometabolism for potential therapy during infection with an emphasis on SARS-CoV2 infection.
Topics: Animals; COVID-19; Humans; Immunity, Innate; Infections; Macrophage Activation; Macrophages; SARS-CoV-2
PubMed: 35154105
DOI: 10.3389/fimmu.2022.780839