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Dynein in Endosome and Phagosome Maturation
Published in Keiko Hirose, Handbook of Dynein, 2019
Ashim Rai, Divya Pathak, Roop Mallik
Phagosome maturation is a series of programmed events by which solid particles (bacteria, parasite, debris) are internalized at the cell membrane for subsequent fusion with degradative lysosomes [39, 89]. This process is fundamentally conserved across evolution, taking place in immune cells (e.g., macrophages and neutrophils) of higher organisms, and also providing nutrition to amoeba (e.g., Dictyostelium). The maturation of a phagosome is intimately linked to its microtubule dependent transport [30], and occurs in two distinct phases (Fig. 9.2). The early phagosome stage is marked by the presence of Rab5 and EEA1 proteins, and involves the fusion of the phagosomes with endocytic vesicles to acquire proteins and lipids necessary for its function [18, 42]. The early stage is also characterized by increasing acidification of the phagosome lumen by the action of proton pumps present on the phagosomal membrane.
Clinical Effects of Pollution
Published in William J. Rea, Kalpana D. Patel, Reversibility of Chronic Disease and Hypersensitivity, Volume 5, 2017
William J. Rea, Kalpana D. Patel
The phagocytic response of the innate immune system is crucial for the effective clearance of microbial pathogens and indispensable for host defense. This response is initiated following microbial pathogens and indispensable for host defense. This response is initiated following microbial contact with host phagocytes (mainly macrophages and neutrophils) and results in the engulfment and killing of microorganisms within phagosomes. Phagocytosis is associated with the production of ROS via the respiratory burst, a necessary effector response for the destruction of intracellular microorganisms.920,921 Although ROS are primarily produced by the NADPH oxidase system I phagocytes, mitochondrial oxidative metabolism is also a major source of cellular ROS. The production of mROS has traditionally been considered a deleterious consequence of electron transport, but mounting evidence indicates that mROS also facilitate antibacterial innate immune signaling and phagocyte bactericidal activity. Leukocytes and lymphocytes often are suppressed in the chemically sensitive with WBC running between 2000 and 5000, which tells that phagocytosis is impaired. These patients are not only prone to recurrent infections but also prone to all kinds of pollutant generated nonbiological inflammations.
Biocompatibility of Powdered Materials: The Influence of Surface Characteristics
Published in Michel Nardin, Eugène Papirer, Powders and Fibers, 2006
Patrick Frayssinet, Patrice Laquerriere
The macrophage is a cell able to internalize the particles by phagocytosis in special internal compartments in order to destroy them by physico-chemical mechanisms (Figure 12.2 and Figure 12.3). Phagocytosis is the ingestion of large particles, minerals, microorganisms, or dead cells in large vesicles called phagosomes. These cells can also fuse to form multinucleated giant cells. Interleukin-4 (IL-4) is able to induce foreign body giant cells from human monocytes and macrophages.2 This effect is optimized with granulocyte macrophage–colony stimulating factor (GM–CSF) or IL-3 (Interleukin-3), dependent on the concentration of IL-4.
Microplastics and human health: Integrating pharmacokinetics
Published in Critical Reviews in Environmental Science and Technology, 2023
Phagocytosis does not seem limited by membrane receptor availability, which are recycled back to the cellular membrane, or energy consumption during internalization, due to intracellular glycogen reserves and anaerobic metabolism (Simon & Schmid-Schönbein, 1988). Instead, phagocytosis seems limited by particle size depending on the availability of excess membrane or contact activator and pseudopod formation in each cell, with the possibility of a single phagosome containing many particles (e.g. 2 µm PS) or a single large particle (e.g. 8 µm PS in human neutrophils), in an inverse correlation of particle number and particle size per phagocyte (Simon & Schmid-Schönbein, 1988). Uptake of particles in the liver can be saturated (K. Ogawara et al., 1999), possibly explained by the limit in immediately available membrane area for phagocytosis. Particle size is also determined by interactions with phagocytes’ membrane ruffles, with ∼2 µm particles being able to establish three contact points between protrusions favoring attachment, remarkably in the same size range of common pathogens (1–4 µm) (Champion et al., 2008). The preference for this size range is supported by many in vitro studies using polymeric particles (i.e., PS), including alveolar rat macrophages (1–6 µm) (Champion et al., 2008), human neutrophils (2–8 µm) (Simon & Schmid-Schönbein, 1988), blood leukocytes (peak 0.6–1 µm, up to 2 µm) (Kawaguchi et al., 1986), mouse peritoneal macrophages (peak 1–2 µm, up to 5 µm) (Tabata & Ikada, 1988), and murine macrophages (10 µm) (Merkley et al., 2022).
Approaches for designing and delivering solid lipid nanoparticles of distinct antitubercular drugs
Published in Journal of Biomaterials Science, Polymer Edition, 2023
Mallikarjun Vasam, Rama Krishna Goulikar
SLNPs loaded with rifampicin (RFP-SLNs) using soybean lecithin, stearic acid, palmitic acid as lipid composition via modified lipid film hydration method with an average size of 830 nm [47]. Alveolar macrophages (AMs), a crucial component of the pulmonary nonspecific immune system, phagocytosed M. tuberculosis that had entered the alveoli via respiration. M. tuberculosis is resistant to the biocidal processes of AMs by blocking phagosome-lysosome fusion, and it uses AMs as an incubator to proliferate. After pulmonary delivery of nontoxic RFP-SLNs, the authors demonstrated that the amount of RFP in AMs was much higher than that in alveolar epithelial type II cells (AECs) at each time point. According to the findings of our study, using solid lipid nanoparticles as a vehicle for selectively delivering rifampicin to alveolar macrophages is a potential new way of treatment [47]. According to reports, negatively charged particles promote immune cell internalization [48], Gaspar et al. reported the rifabutin-loaded SLNPs to treat pulmonary tuberculosis. In the production of SLNPs, two distinct formulations were created by utilizing glyceryl dibehenate and glyceryl tristearate, respectively, as lipid ingredients. The in vitro findings using THP1 cells that had been differentiated into macrophages, these two formulations demonstrated efficient nanoparticle uptake by 46 and 26% respectively [49].