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Nature Reviews. Immunology Aug 2014The mononuclear phagocyte system (MPS) has historically been categorized into monocytes, dendritic cells and macrophages on the basis of functional and phenotypical... (Review)
Review
The mononuclear phagocyte system (MPS) has historically been categorized into monocytes, dendritic cells and macrophages on the basis of functional and phenotypical characteristics. However, considering that these characteristics are often overlapping, the distinction between and classification of these cell types has been challenging. In this Opinion article, we propose a unified nomenclature for the MPS. We suggest that these cells can be classified primarily by their ontogeny and secondarily by their location, function and phenotype. We believe that this system permits a more robust classification during both steady-state and inflammatory conditions, with the benefit of spanning different tissues and across species.
Topics: Animals; Cell Differentiation; Dendritic Cells; Humans; Macrophages; Mice; Monocytes; Mononuclear Phagocyte System; Phagocytosis; Terminology as Topic
PubMed: 25033907
DOI: 10.1038/nri3712 -
Advanced Materials (Deerfield Beach,... Apr 2022Lipid nanoparticles (LNPs) are the leading nonviral technologies for the delivery of exogenous RNA to target cells in vivo. As systemic delivery platforms, these...
Lipid nanoparticles (LNPs) are the leading nonviral technologies for the delivery of exogenous RNA to target cells in vivo. As systemic delivery platforms, these technologies are exemplified by Onpattro, an approved LNP-based RNA interference therapy, administered intravenously and targeted to parenchymal liver cells. The discovery of systemically administered LNP technologies capable of preferential RNA delivery beyond hepatocytes has, however, proven more challenging. Here, preceded by comprehensive mechanistic understanding of in vivo nanoparticle biodistribution and bodily clearance, an LNP-based messenger RNA (mRNA) delivery platform is rationally designed to preferentially target the hepatic reticuloendothelial system (RES). Evaluated in embryonic zebrafish, validated in mice, and directly compared to LNP-mRNA systems based on the lipid composition of Onpattro, RES-targeted LNPs significantly enhance mRNA expression both globally within the liver and specifically within hepatic RES cell types. Hepatic RES targeting requires just a single lipid change within the formulation of Onpattro to switch LNP surface charge from neutral to anionic. This technology not only provides new opportunities to treat liver-specific and systemic diseases in which RES cell types play a key role but, more importantly, exemplifies that rational design of advanced RNA therapies must be preceded by a robust understanding of the dominant nano-biointeractions involved.
Topics: Animals; Lipids; Liposomes; Liver; Mice; Mononuclear Phagocyte System; Nanoparticles; RNA, Messenger; RNA, Small Interfering; Tissue Distribution; Zebrafish
PubMed: 35218106
DOI: 10.1002/adma.202201095 -
Neuron Nov 2022CNS-resident macrophages-including parenchymal microglia and border-associated macrophages (BAMs)-contribute to neuronal development and health, vascularization, and... (Review)
Review
CNS-resident macrophages-including parenchymal microglia and border-associated macrophages (BAMs)-contribute to neuronal development and health, vascularization, and tissue integrity at steady state. Border-patrolling mononuclear phagocytes such as dendritic cells and monocytes confer important immune functions to the CNS, protecting it from pathogenic threats including aberrant cell growth and brain malignancies. Even though we have learned much about the contribution of lymphocytes to CNS pathologies, a better understanding of differential roles of tissue-resident and -invading phagocytes is slowly emerging. In this perspective, we propose that in CNS neuroinflammatory diseases, tissue-resident macrophages (TRMs) contribute to the clearing of debris and resolution of inflammation, whereas blood-borne phagocytes are drivers of immunopathology. We discuss the remaining challenges to resolve which specialized mononuclear phagocyte populations are driving or suppressing immune effector function, thereby potentially dictating the outcome of autoimmunity or brain cancer.
Topics: Humans; Mononuclear Phagocyte System; Microglia; Phagocytes; Macrophages; Monocytes; Brain Neoplasms
PubMed: 36327896
DOI: 10.1016/j.neuron.2022.10.005 -
British Medical Journal Jan 1955
Topics: Dermatitis, Exfoliative; Disease; Humans; Mononuclear Phagocyte System; Sezary Syndrome
PubMed: 13219396
DOI: 10.1136/bmj.1.4908.256 -
Immunobiology 2010
Topics: Allergy and Immunology; Host-Pathogen Interactions; Immunophenotyping; Mononuclear Phagocyte System; Societies, Scientific
PubMed: 20692532
DOI: 10.1016/j.imbio.2010.07.001 -
Seminars in Immunology Dec 2017Nanoparticles represent a new generation of drug delivery systems that can be engineered to harness optimal target selectivity for specific cells and tissues and high... (Review)
Review
Nanoparticles represent a new generation of drug delivery systems that can be engineered to harness optimal target selectivity for specific cells and tissues and high drug loading capacity, allowing for improved pharmacokinetics and enhanced bioavailability of therapeutics. The spontaneous propensity of both organic and colloidal nanoparticles to be captured by the cells of the reticuloendothelial system encouraged their utilization as passive targeting systems that can be preferentially directed to innate immune cells, such as macrophages, dendritic cells and neutrophils. The natural affinity for phagocytic cells suggests the possible implementation of nanoparticles as an immunotherapeutic platform for inflammatory diseases and autoimmune disorders. Here we discuss the recent advances in the application of nanotechnology to induce antigen-specific tolerance in autoimmunity and the use of nanoparticles for anti-inflammatory therapies, including treatment of inflammatory bowel diseases, psoriasis and rheumatoid arthritis.
Topics: Autoimmunity; Colloids; Dendritic Cells; Drug Delivery Systems; Humans; Immune Tolerance; Immunity, Innate; Macrophages; Mononuclear Phagocyte System; Nanomedicine; Nanoparticles; Nanotechnology; Neutrophils; Phagocytosis
PubMed: 28855088
DOI: 10.1016/j.smim.2017.08.010 -
Frontiers in Immunology 2020The central nervous system (CNS) parenchyma is enclosed and protected by a multilayered system of cellular and acellular barriers, functionally separating glia and... (Review)
Review
The central nervous system (CNS) parenchyma is enclosed and protected by a multilayered system of cellular and acellular barriers, functionally separating glia and neurons from peripheral circulation and blood-borne immune cells. Populating these borders as dynamic observers, CNS-resident macrophages contribute to organ homeostasis. Upon autoimmune, traumatic or neurodegenerative inflammation, these phagocytes start playing additional roles as immune regulators contributing to disease evolution. At the same time, pathological CNS conditions drive the migration and recruitment of blood-borne monocyte-derived cells across distinct local gateways. This invasion process drastically increases border complexity and can lead to parenchymal infiltration of blood-borne phagocytes playing a direct role both in damage and in tissue repair. While recent studies and technical advancements have highlighted the extreme heterogeneity of these resident and CNS-invading cells, both the compartment-specific mechanism of invasion and the functional specification of intruding and resident cells remain unclear. This review illustrates the complexity of mononuclear phagocytes at CNS interfaces, indicating how further studies of CNS border dynamics are crucially needed to shed light on local and systemic regulation of CNS functions and dysfunctions.
Topics: Animals; Cell Communication; Cell Movement; Central Nervous System; Central Nervous System Diseases; Humans; Inflammation; Inflammation Mediators; Macrophages; Mononuclear Phagocyte System; Signal Transduction
PubMed: 33746939
DOI: 10.3389/fimmu.2020.609921 -
American Journal of Transplantation :... Apr 2016The mononuclear phagocyte system (MPS) comprises monocytes, macrophages and dendritic cells (DCs). Over the past few decades, classification of the cells of the MPS has... (Review)
Review
The mononuclear phagocyte system (MPS) comprises monocytes, macrophages and dendritic cells (DCs). Over the past few decades, classification of the cells of the MPS has generated considerable controversy. Recent studies into the origin, developmental requirements and function of MPS cells are beginning to solve this problem in an objective manner. Using high-resolution genetic analyses and fate-mapping studies, three main mononuclear phagocyte lineages have been defined, namely, macrophage populations established during embryogenesis, monocyte-derived cells that develop during adult life and DCs. These subsets and their diverse subsets have specialized functions that are largely conserved between species, justifying the introduction of a new, universal scheme of nomenclature and providing the framework for therapeutic manipulation of immune responses in the clinic. In this review, we have commented on the implications of this novel MPS classification in solid organ transplantation.
Topics: Adult; Animals; Humans; Mononuclear Phagocyte System; Organ Transplantation
PubMed: 26602545
DOI: 10.1111/ajt.13627 -
Frontiers in Immunology 2018The mononuclear phagocyte system (MPS) constitutes dendritic cells, monocytes, and macrophages. This system contributes to various functions that are essential for... (Review)
Review
The mononuclear phagocyte system (MPS) constitutes dendritic cells, monocytes, and macrophages. This system contributes to various functions that are essential for maintaining homeostasis, activation of innate immunity, and bridging it with the adaptive immunity. Consequently, MPS is highly important in bolstering immunity against the pathogens. However, MPS is the frontline cells in destroying (), yet the bacterium prefers to reside in the hostile environment of macrophages. Therefore, it may be very interesting to study the struggle between and MPS to understand the outcome of the disease. In an event when MPS predominates , the host remains protected. By contrast, the situation becomes devastating when the pathogen tames and tunes the host MPS, which ultimately culminates into tuberculosis (TB). Hence, it becomes extremely crucial to reinvigorate MPS functionality to overwhelm and eliminate it. In this article, we discuss the strategies to bolster the function of MPS by exploiting the molecules associated with the innate immunity and highlight the mechanisms involved to overcome the -induced suppression of host immunity. In future, such approaches may provide an insight to develop immunotherapeutics to treat TB.
Topics: Adaptive Immunity; Animals; Dendritic Cells; Humans; Immunity, Innate; Inflammation; Macrophages; Mice; Monocytes; Mononuclear Phagocyte System; Mycobacterium tuberculosis; Tuberculosis
PubMed: 29479353
DOI: 10.3389/fimmu.2018.00193 -
Nature Reviews. Immunology May 2017Major advances in mononuclear phagocyte biology have been made but key questions pertinent to their roles in health and disease remain, including in the visual system.... (Review)
Review
Major advances in mononuclear phagocyte biology have been made but key questions pertinent to their roles in health and disease remain, including in the visual system. One problem concerns how dendritic cells can trigger immune responses from certain tightly regulated immune- privileged sites of the eye. Another, albeit separate, problem involves whether there are functional specializations for microglia versus monocytes in retinal neurodegeneration. In this Review, we examine novel insights in eye immune privilege and, separately, we discuss recent inroads concerning retinal degeneration. Both themes have been extensively studied in the visual system and show parallels with recent findings concerning mononuclear phagocytes in the central nervous system and in the periphery.
Topics: Animals; Eye; Humans; Mononuclear Phagocyte System; Retina; Visual Perception
PubMed: 28345586
DOI: 10.1038/nri.2017.13