Browsing by Subject "Phagocytosis"
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- PublicationOpen AccessBovine oviduct epithelial cells suppress the phagocytic activity of neutrophils towards sperm but not for bacteria in vitro: Immunofluorescence and electron microscopic observations(Universidad de Murcia, Departamento de Biologia Celular e Histiologia, 2020) Marey, Mohamed Ali; Matsukawa, Haruhisa; Sasaki, Motoki; Ezz, Mohamed Aboul; Yousef, Mohamed Samy; Takahashi, Ken-ichi; Miyamoto, AkioPreviously, we reported that polymorpho- nuclear neutrophils (PMNs) are constantly existent in the bovine oviduct fluid during the pre-ovulatory stage under physiological conditions. Moreover, incubation of PMNs with bovine oviduct epithelial cells-conditioned medium (BOEC-CM) resulted in suppression of their phagocytic activity for sperm. During pathophysiological conditions, cows may be inseminated by infected semen which exposes oviductal PMNs to allogenic sperm simultaneously with pathogens. This study aimed to visually investigate the role of oviduct epithelium in regulating the phagocytic behavior of PMNs toward sperm as a physiological stimulus, with Escherichia coli (E. coli) as a pathological stimulus. In our experiment, PMNs were incubated for 2 h in BOEC-CM. Phagocytosis was then assayed by co-incubation of these PMNs either with sperm, E. coli, or latex beads. BOEC- CM significantly suppressed the direct phagocytosis of PMNs for sperm, but did not affect their phagocytic activity for E. coli or latex beads. Additionally, an investigation with scanning electron microscopy revealed that BOEC-CM suppressed the formation of DNA-based neutrophil extracellular traps (NETs) for sperm entanglement. BOEC-CM did not alter NETs formation towards E. coli. A quantification of NETs formation using an immunofluorescence microscopy showed that the areas of NETs formation for E. coli were significantly larger than those formed for sperm. Our data clearly show that the bovine oviduct, through secretions, protects sperm from phagocytosis by PMNs and eliminates bacterial dissemination through maintaining the phagocytic activity of PMNs towards bacteria
- PublicationOpen AccessCellular mechanisms of calcium phosphate ceramic degradation(Murcia : F. Hernández, 1999) Heymann, D.; Pradal, G.; Benahmed, M.Calcium phosphate (Cap) ceramics are widely used for bone substitution in orthopedic, maxillofacial and dental surgery. Many environmental factors are involved in the gradual degradation of calcium phosphate ceramic after implantation, including physicochemical processes (dissolution-precipitation) and the effects of various cell types. Several of these cell types degrade ceramics by, phagocytotic mechanisms (fibroblasts, osteoblasts, monocytes/macrophages) or by an acidic mechanism with a proton pump to reduce the pH of the microenvironment and resorb these synthetic substrates (osteoclasts). Various mesenchymal cells located at the implantation sites can induce the solubilization of Cap ceramics. Crystal-cell contacts were required to induce such crystal dissolution. Mesenchymal cells such as fibroblastic cells are also actively involved in the ceramic degradation process. In this context, Cap crystals underwent dissolution into the phagosome. If osteoclasts resorb Cap ceramics similarly to the natural bone, they possess a phagocytic capability. This phagocytosis mechanism consisted of three steps: crystal phagocytosis, disappearance of the endophagosome envelope membrane and fragmentation of phagocytosed crystals within the cytoplasm. Similar phenomenons have been observed during the phagocytic mechanism induced by monocytes/macrophages. The cellular mechanisms of Cap ceramic degradation are modulated by various parameters, such as the properties of the ceramic itself, the implantation sites and the presence of various proteins (cytokines, hormones, vitamins, ions, etc.). The cells involved in these mechanisms could intervene directly or indirectly through their cytokinelgrowth factor secretions and their sensitivity to the same molecules. This article reviews recent knowledge on the cellular mechanisms of calcium phosphate ceramic degradation.
PublicationOpen AccessErythrocyte phagocytosis in gilthead seabream (Sparus aurata) and European sea bass (Dicentrarchus labrax).(2024-11-04) Campos Sánchez, Jose Carlos; Guardiola, Francisco A.; Meseguer, José; Esteban Abad, María Ángeles; Biología Celular e Histología- PublicationEmbargoInfluence of adult Anguillicoloides crassus load in European eels swimbladder on macrophage response(Elsevier, 2015) Muñoz, Pilar; Peñalver, José; Ruiz de Ybanez, R.; Garcia, J.; Sanidad AnimalAnguillicoloides crassus has become one of the most important threats to the European eel (Anguilla anguilla). Adult parasites colonize the swimbladder leading to an impaired functioning of this organ. The infection is also responsible for an increased in the stress level of infected eels, that could produce an altered immune response as well. Differences in parasite loads and effects in the European and Japanese eel (Anguilla japonica) have been described. We have studied the influence of the number of adult parasites present in the swimbladder of wild eels on the macrophage response (phagocytosis and respiratory burst) as part of the first immune response to pathogens. Our results show an increased phagocytozed bacterial survival 24 h post-infection in macrophages of eels infected with more than ten adult parasites compared to macrophages from eels infected with less than those ten adult parasites. Respiratory burst results also showed a less efficient response in macrophages from eels infected with more than ten adult parasites, although in this case results were not found to be significant.
- PublicationOpen AccessMicroglial cells during the lesion-regeneration of the lizard medial cortex(Murcia : F. Hernández, 1999) Nacher, J.; Ramírez, G.; Palop, J.J.; Artal Soriano, Pablo; Molowny, A.; López-García, CarlosThe lizard medial cortex (lizard fascia dentata) is capable of neural regeneration after being lesioned by the anti-metabolite 3-acetylpyridine (3AP). This study was aimed at detecting microglial behaviour during the medial cortex lesion-regeneration process using tomato lectin histochemistry to label microglia (both with light and electron microscopy) and proliferating cell nuclear antigen (PCNA) immunocytochemistry to label proliferating cells. As expected, 1-2 days post-injection lectin-labelled microglia cells could not be observed in the medial cortex plexiform layers, but later (7 days post-injection) abundant lectin-labelled microglia cells re-populated the regenerating medial cortex. Abundant PCNA-immunolabelled nuclei were detected both in the subjacent ependymal neuroepithelium (neuroblasts, maximum at 2 days postinjection) as well as in some parenchyma1 cells which were also lectin-labelled (microglia, maximum at 7-15 days post-injection). Re-invasive microglia were also detected in the vicinity of ventricular ependymal lining, blood vessels and meninges. The electron microscope demonstrated that these microglial cells participate in cell debris removal, especially of neural granular cell somata. Other cell types related to microglia (mast cells, peri-vascular cells and meningeal cells) were also present during the scavenging process. Significant numbers of microglial cells remained in close relationship with the ependymal proliferative areas, even in control non-lesioned animals. This is indirect evidence for the working hypothesis that microglia are not only implicated in cell debris removal, but also in the regulation of newly generated neuroblast incorporation onto the cortical areas. Whether they phagocytose immature neuroblasts or induce cell death in them or even prevent their migration onto the principal layer areas are likely possibilities that remain to be proven.
- PublicationOpen AccessPotential of Sulforaphane and Broccoli Membrane Vesicles as Regulators of M1/M2 Human Macrophage ActivityRamirez Pavez, T. N.; García Peñaranda, A.; Garcia Ibañez, P.; Yepes Molina, L.; Carvajal Alcaraz, M.; Ruiz Alcaraz, A. J.; Moreno Fernández, D.; Garcia Peñarrubia, M. D. P.; Martínez-Esparza, M.; Bioquímica y Biología Molecular B e Inmunología
- PublicationOpen AccessRab GTPases in the differential processing of phagocytosed pathogens versus efferocytosed apoptotic cells(Universidad de Murcia, Departamento de Biologia Celular e Histiologia, 2021) Taefehshokr, Nima; Yin, Charles; Heit, BryanPhagocytosis is an important feature of innate immunity in which invading microorganisms are engulfed, killed and degraded - and in some immune cells, their antigens presented to the adaptive immune system. A closely related process, efferocytosis, removes apoptotic cells, and is essential for the maintenance of homeostasis. Both phagocytosis and efferocytosis are tightly regulated processes that involve target recognition and uptake through specific receptors, followed by endolysosomal trafficking and processing of the internalized target. Central to the uptake and trafficking of these targets are the Rab family of small GTPases, which coordinate the engulfment and trafficking of both phagocytosed and efferocytosed materials through the endolysosomal system. Because of this regulatory function, Rab GTPases are often targeted by pathogens to escape phagocytosis. In this review, we will discuss the shared and differential roles of Rab GTPases in phagocytosis and efferocytosis.
- PublicationOpen AccessUltrastructural evidence in vitro of osteoclast-induced degradation of calcium phosphate ceramic by simultaneous resorption and phagocytosis mechanisms(Murcia : F. Hernández, 2001) Heymann, D.; Guicheux, J.; Rousselle, A.V.Osteoclasts are physiological polykaryons specialized in the resorption of calcified tissue. In the context of the clinical use of calcium-phosphate (Cap) ceramics as bone substitutes, this study used transmission electron microscopy to investigate the in vitro mechanisms of Cap ceramic degradation by osteoclastic cell types. Osteoclasts cultured on Cap ceramic developed typical ultrastructural features of bone osteoclasts, such as a polarized dome shape, a clear zone and a ruffled border. Modification of the shape and density of Cap crystals under the ruffled border indicated an acidic microenvironment. Moreover, osteoclasts were able to degrade ceramic by simultaneous resorption and phagocytosis mechanisms. Phagocytosis did not alter the ability of osteoclasts to resorb Cap ceramic. The phagocytosis mechanism consisted of three steps: crystal phagocytosis, disappearance of the endophagosome envelope membrane and fragmentation of phagocytosed crystals within the cytoplasm. The common mechanism of phagocytosis described here is similar to that observed with the monocyte/macrophage lineage, confirming that osteoclasts are part of the mononuclear phagocyte system. Osteoclasts are thus clearly involved in Cap degradation by means of resorption and phagocytosis
- PublicationOpen AccessWhen intracellular pathogens invade the frontiers of cell biology and immunology(Murcia : F. Hernández, 1997) Pizarro-Cerdá, J.; Moreno, E.; Desjardins, M.; Gorvel, J.P.Cellular microbiology has recently been described as a new discipline emerging at the interface between cell biology and rnicrobiology (Cossart et al., 1996). Many microbial pathogens can enter eukaryotic cells and live intracellularly either inside vacuoles or in the cytoplasm. The different steps during the invasion process are on the way of being dissected at the molecular leve1 revealing new insights in basic cellular functions. Indeed, bacterial pathogenesis can help us to better understand the dynamics of cell cytoskeleton, intracellular membrane traffic and signal transduction events. The recent advancements in the field of microbial pathogenesis are creating a new cross-taik between cell biologists, microbiologists and immuno-logists. In this review, the different strategies used by several pathogens are presented and the mechanisms elaborated by host cells from the immune system to eliminate the parasites discussed.