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Journal of Leukocyte Biology Sep 1994Infection of the central nervous system by HIV-1 results in widespread neuropathology and neurological symptoms. The cells infected in the brain belong to the... (Review)
Review
Infection of the central nervous system by HIV-1 results in widespread neuropathology and neurological symptoms. The cells infected in the brain belong to the mononuclear phagocyte lineage. We review aspects of the biology of the macrophage populations associated with the central nervous system and consider their distribution, phenotype, and kinetics in relation to HIV pathology.
Topics: Central Nervous System; HIV Infections; Humans; Phagocytes; Phenotype
PubMed: 8083615
DOI: 10.1002/jlb.56.3.399 -
Annals of Internal Medicine Sep 1978Phagocytosis is a cellular function relevant for host defense against infection, tissue turnover, and other aspects of human physiology. Phagocytosis is also... (Review)
Review
Phagocytosis is a cellular function relevant for host defense against infection, tissue turnover, and other aspects of human physiology. Phagocytosis is also representative of functions wherein external stimuli activate motile events in the cell. Recognition of suitable objects by the plasma membrane of the phagocyte initiates phagocytosis. Knowledge of serum proteins that coat objects rendering them recognizable is considerable, but understanding of the chemical basis of recognition is meager. The signals activated by recognition are also not known. The work of phagocytosis that causes pseudopodia to enclose objects in vacuoles is ascribable to metabolic energy-dependent interactions between actin filaments and other contractile proteins in the peripheral cytoplasm. These interactions may also regulate the fusion of lysosomes with phagocytic vacuoles, an event important for the processing of ingested objects after phagocytosis.
Topics: Actins; Adhesiveness; Cytochalasin B; Humans; Infant; Male; Myosins; Neutrophils; Phagocytes; Phagocytosis; Protein Binding; Proteins
PubMed: 356692
DOI: 10.7326/0003-4819-89-3-398 -
Glia Jun 2022Elimination of dead or live cells take place in both a healthy and diseased central nervous system (CNS). Dying or dead cells are quickly cleared by phagocytosis for the... (Review)
Review
Elimination of dead or live cells take place in both a healthy and diseased central nervous system (CNS). Dying or dead cells are quickly cleared by phagocytosis for the maintenance of a healthy CNS or for recovery after injury. Live cells or parts thereof, such as the synapses and myelin, are appropriately eliminated by phagocytosis to maintain or refine neural networks during development and adulthood. Microglia, the specific population of resident macrophages in the CNS, are classically considered as primary phagocytes; however, astrocytes have also been highlighted as phagocytes in the last decade. Phagocytic targets and receptors are reported to be mostly common between astrocytes and microglia, which raises the question of how astrocytic phagocytosis differs from microglial phagocytosis, and how these two phagocytic systems cooperate. In this review, we address the consequences of astrocytic phagocytosis, particularly focusing on these elusive points.
Topics: Astrocytes; Central Nervous System; Microglia; Phagocytes; Phagocytosis
PubMed: 35142399
DOI: 10.1002/glia.24145 -
Annales de Pathologie 1986Histo-monocytes are cells playing an important role in host defense reaction and purification of the organism. These cells belong to a new system of highly phagocytic... (Review)
Review
Histo-monocytes are cells playing an important role in host defense reaction and purification of the organism. These cells belong to a new system of highly phagocytic mononuclear cells termed "mononuclear phagocyte system". This system includes the promonocytes and their precursors in the bone marrow, the monocytes in the peripheral blood and the different types of histiocytes and macrophages particularly Kupffer cells. Histiocytes can also transform into epithelioid cells and giant cells. The inclusion of all these cells in this system is based on similarities in the morphology, function, origin and kinetics of the phagocytes. The most important morphologic characteristics of these cells are described. It is also shown that the mononuclear phagocytic system is a secretory system. The different types of products are described. Recently, so-called accessory cells of the immunity were described, comprising dendritic reticular cells from the follicles and interdigitating reticular cells from the deep cortical zone of the lymph node. Those cells belong both probably to the system. The cells of this system are engaged in the clearance of multiple organs, in the inflammatory process, in the immune response and in the immune surveillance against tumor.
Topics: Animals; Antibody Formation; Blood Coagulation; Complement System Proteins; Hematopoiesis; Histiocytes; Humans; Hydrolases; Immunity, Cellular; Inflammation; Lipid Metabolism; Monocytes; Monokines; Muramidase; Peptide Hydrolases; Phagocytes; Phagocytosis; Proteins; Stem Cells
PubMed: 3521627
DOI: No ID Found -
DNA and Cell Biology Feb 2021Effective and efficient efferocytosis of dead cells and associated cellular debris are critical to tissue homeostasis and healing of injured tissues. This important task... (Review)
Review
Effective and efficient efferocytosis of dead cells and associated cellular debris are critical to tissue homeostasis and healing of injured tissues. This important task was previously thought to be restricted to professional phagocytes (PPs). However, accumulating evidence has revealed another type of phagocyte, the amateur phagocyte (AP), which can also participate in efferocytosis. APs are non-myeloid progenitor/nonimmune cells that include differentiated cells (e.g., epithelial cells, fibroblasts, and endothelial cells [ECs]) and stem cells (e.g., neuronal progenitor cells and mesenchymal cells) and can be found throughout the human body. Studies have shown that APs have two prominent roles: identifying and removing dead cells presumably before PPs reach the site of injury and assisting PPs in the removal of cell corpses and the resolution of inflamed tissue. With respect to the engulfment and degradation of dead cells, APs are slower and less efficient than PPs. However, APs are fundamental to preventing the spread of inflammation over a large area. In this review, we present the diversity and characteristics of healthy and non-neoplastic APs in mammals. We also propose a hypothetical mechanism of the efferocytosis of immunoglobulin G (IgG)-opsonized myelin debris by ECs (APs). Furthermore, the ingestion and clearance of dead cells can induce proinflammatory or anti-inflammatory cytokine production, endothelial activation, and cellular fate transition, which contribute to the progression of disease. An understanding of the role of APs is necessary to develop effective intervention strategies, including potential molecular targets for clinical diagnosis and drug development, for inflammation-related diseases.
Topics: Animals; Humans; Phagocytes
PubMed: 33439750
DOI: 10.1089/dna.2020.5647 -
Cell Host & Microbe Nov 2010Statins are inhibitors of 3-hydroxy 3-methylglutaryl coenzyme A (HMG-CoA) reductase, the rate-limiting enzyme in cholesterol biosynthesis. Recent clinico-epidemiologic...
Statins are inhibitors of 3-hydroxy 3-methylglutaryl coenzyme A (HMG-CoA) reductase, the rate-limiting enzyme in cholesterol biosynthesis. Recent clinico-epidemiologic studies correlate patients receiving statin therapy with having reduced mortality associated with severe bacterial infection. Investigating the effect of statins on the innate immune capacity of phagocytic cells against the human pathogen Staphylococcus aureus, we uncovered a beneficial effect of statins on bacterial clearance by phagocytes, although, paradoxically, both phagocytosis and oxidative burst were inhibited. Probing instead for an extracellular mechanism of killing, we found that statins boosted the production of antibacterial DNA-based extracellular traps (ETs) by human and murine neutrophils and also monocytes/macrophages. The effect of statins to induce phagocyte ETs was linked to sterol pathway inhibition. We conclude that a drug therapy taken chronically by millions alters the functional behavior of phagocytic cells, which could have ramifications for susceptibility and response to bacterial infections in these patients.
Topics: Acyl Coenzyme A; Animals; Cells, Cultured; DNA, Bacterial; Extracellular Space; Humans; Hydroxymethylglutaryl-CoA Reductase Inhibitors; Macrophages; Male; Mice; Mice, Inbred C57BL; Mice, Inbred CFTR; Neutrophils; Phagocytes; Pneumonia, Staphylococcal; Staphylococcus aureus
PubMed: 21075355
DOI: 10.1016/j.chom.2010.10.005 -
Immunological Reviews Oct 2007
Topics: Animals; Bacterial Infections; Humans; Immunity, Innate; Leishmaniasis; Phagocytes; Phagocytosis
PubMed: 17850477
DOI: 10.1111/j.1600-065X.2007.00568.x -
Phagocyte dynamics in a highly regenerative urochordate: insights into development and host defense.Developmental Biology Feb 2013Phagocytosis is a cellular process by which particles and foreign bodies are engulfed and degraded by specialized cells. It is functionally involved in nutrient...
Phagocytosis is a cellular process by which particles and foreign bodies are engulfed and degraded by specialized cells. It is functionally involved in nutrient acquisition and represents a fundamental mechanism used to remove pathogens and cellular debris. In the marine invertebrate chordate Botryllus schlosseri, cell corpse engulfment by phagocytic cells is the recurrent mechanism of programmed cell clearance and a critical process for the successful execution of asexual regeneration and colony homeostasis. In the present study, we have utilized a naturally occurring process of vascular parabiosis coupled with intravascular microinjection of fluorescent bioparticles and liposomes as tools to investigate the dynamics of phagocyte behavior in real-time during cyclical body regeneration. Our findings indicate that B. schlosseri harbors two major populations of post-mitotic phagocytes, which display distinct phagocytic specificity and homing patterns: a static population that lines the circulatory system epithelia, and a mobile population that continuously recirculates throughout the colony and exhibits a characteristic homing pattern within mesenchymal niches called ventral islands (VI). We observed that a significant proportion of ventral island phagocytes (VIP) die and are engulfed by other VIP following takeover. Selective impairment of VIP activity curtailed zooid resorption and asexual development. Together, these findings strongly suggest that ventral islands are sites of phagocyte homing and turnover. As botryllid ascidians represent invertebrate chordates capable of whole body regeneration in a non-embryonic scenario, we discuss the pivotal role that phagocytosis plays in homeostasis, tissue renewal and host defense.
Topics: Animals; Cell Movement; Fungi; Gram-Negative Bacteria; Gram-Positive Bacteria; Microscopy, Confocal; Microscopy, Electron, Transmission; Mitosis; Models, Biological; Phagocytes; Phagocytosis; Regeneration; Time Factors; Urochordata
PubMed: 23174529
DOI: 10.1016/j.ydbio.2012.11.006 -
Acta Paediatrica Hungarica
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Frontiers in Endocrinology 2020Atherosclerosis (AS) is the main pathological basis for the development of cardio-cerebrovascular diseases. Abnormal accumulation of apoptotic and necrotic cells... (Review)
Review
Atherosclerosis (AS) is the main pathological basis for the development of cardio-cerebrovascular diseases. Abnormal accumulation of apoptotic and necrotic cells resulted in plaque enlargement, necrotic core formation and plaque rupture in AS. Under physiological conditions, apoptotic cells (ACs) could be effectively phagocytized and cleared by phagocyte-mediated efferocytosis. In contrast, the clearance efficiency of ACs in AS plaque was much lower because of the impaired efferocytosis in AS. Recent findings have made great progress on the molecular mechanisms of efferocytosis process and dynamic regulation, and its dysfunction on organismal health. Yet, there are still few effective treatments for this process. This article reviews the mechanism of efferocytosis and the role of efferocytosis in AS, highlighting a novel therapeutic strategy for AS, which mainly prevents the progression of plaque by targeting efferocytosis.
Topics: Animals; Apoptosis; Atherosclerosis; Humans; Necrosis; Phagocytes; Phagocytosis
PubMed: 33597922
DOI: 10.3389/fendo.2020.585285