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Research in Veterinary Science 1997The ability of macrophages isolated from the bovine mammary gland to phagocytose and kill Streptococcus uberis was investigated. The strains of S uberis used were...
The ability of macrophages isolated from the bovine mammary gland to phagocytose and kill Streptococcus uberis was investigated. The strains of S uberis used were selected on the basis of their known resistance (C197C) or sensitivity (EF20) to phagocytosis by bovine peripheral blood neutrophils in the same assay system. Macrophages isolated from mammary secretions collected during the mid-dry period were capable of phagocytosing both strains of S uberis in the presence of serum and skimmed milk. The removal of complement from serum by heat-inactivation did not influence the opsonization of S uberis for phagocytosis by mammary macrophages and both IgG1 and IgG2 isotypes were found to opsonise both strains. The uptake of S uberis into the cells was confirmed by electron microscopy. Potential mechanisms by which S uberis could resist phagocytosis by neutrophils but not by macrophages are discussed.
Topics: Animals; Cattle; Cells, Cultured; Complement System Proteins; Female; Immunoglobulin G; Isomerism; Macrophages; Mammary Glands, Animal; Microscopy, Electron; Phagocytosis; Streptococcus
PubMed: 9160429
DOI: 10.1016/s0034-5288(97)90184-3 -
Medecine Sciences : M/S 2016
Topics: Chemotaxis; Homeostasis; Humans; Phagocytosis; Phosphatidylinositol 3-Kinases; Protein Binding; Signal Transduction
PubMed: 27406768
DOI: 10.1051/medsci/20163206021 -
Current Opinion in Cell Biology Dec 2021Neuronal-immune interactions are known to play crucial roles in brain development and homoeostasis. Of great relevance in this context are microglia, brain macrophages... (Review)
Review
Neuronal-immune interactions are known to play crucial roles in brain development and homoeostasis. Of great relevance in this context are microglia, brain macrophages that phagocytose neurons that die during development, and many neurological disorders. Single-cell RNA sequencing methods have significantly advanced our understanding of microglial heterogeneity and transcriptional response to environmental changes. Here, we review recent work showing how microglia adopt a similar molecular signature during development and disease characterised by the expression of genes linked to phagocytosis and lipid uptake and metabolism. These studies show that in many neurodegenerative conditions, microglia accumulate cholesterols and lipid-rich debris, pointing to lipid processing and transport as promising targets for developing new therapeutical treatments against neurodegenerative disorders.
Topics: Brain; Macrophages; Microglia; Neurons; Phagocytosis; Weight Prejudice
PubMed: 34455405
DOI: 10.1016/j.ceb.2021.07.007 -
Current Opinion in Neurobiology Jun 2024Microglia are tissue-resident macrophages and professional phagocytes of the central nervous system (CNS). In development, microglia-mediated phagocytosis is important... (Review)
Review
Microglia are tissue-resident macrophages and professional phagocytes of the central nervous system (CNS). In development, microglia-mediated phagocytosis is important for sculpting the cellular architecture. This includes the engulfment of dead/dying cells, pruning extranumerary synapses and axons, and phagocytosing fragments of myelin sheaths. Intriguingly, these developmental phagocytic mechanisms by which microglia sculpt the CNS are now appreciated as important for eliminating synapses, myelin, and proteins during neurodegeneration. Here, we discuss parallels between neurodevelopment and neurodegeneration, which highlights how development is informing disease. We further discuss recent advances and challenges towards therapeutically targeting these phagocytic pathways and how we can leverage development to overcome these challenges.
Topics: Humans; Microglia; Animals; Phagocytosis; Neurodegenerative Diseases; Myelin Sheath; Central Nervous System
PubMed: 38631077
DOI: 10.1016/j.conb.2024.102877 -
American Journal of Reproductive... Jul 2010Apoptosis is a normal constituent of trophoblast turnover in the placenta; however in some cases, this process is related to pregnancy complications such as...
PROBLEM
Apoptosis is a normal constituent of trophoblast turnover in the placenta; however in some cases, this process is related to pregnancy complications such as preeclampsia. Recognition and engulfment of these apoptotic trophoblast cells is important for clearance of dying cells. The aim of this study was to show the cross talk between human endometrial endothelial cells (HEECs) and apoptotic trophoblast cells in an in vitro coculture model and its effect on cytokine production by HEECs.
METHOD OF STUDY
Fluorescent-labeled HEECs were cocultured with fluorescent-labeled apoptotic human trophoblast cells. Confocal microscopy and flow cytometry were used to show the interaction between these two types of cells. Cytokine profiles were determined using multiplex analysis.
RESULTS
HEECs are capable to phagocytose apoptotic trophoblasts. This activity is inhibited by the phagocytosis inhibitor cytochalasin B. Phagocytosis of apoptotic trophoblast cells induced the secretion of the proinflammatory cytokines interleukin-6 and monocyte chemoattractant protein-1 by HEECs.
CONCLUSION
This study provides the first evidence that HEECs have an ability to phagocytose apoptotic trophoblasts. Furthermore, we demonstrated an inflammatory response of HEECs after phagocytosing the apoptotic trophoblast cells. This event may contribute to the inflammatory response in both normal pregnancy and pathologic pregnancy such as preeclampsia.
Topics: Apoptosis; Cells, Cultured; Endometrium; Endothelial Cells; Female; Flow Cytometry; Humans; Inflammation Mediators; Interleukin-6; Microscopy, Confocal; Microscopy, Fluorescence; Phagocytosis; Trophoblasts
PubMed: 20219062
DOI: 10.1111/j.1600-0897.2010.00815.x -
Journal of Neuroinflammation Aug 2012Microglia are resident brain macrophages that can phagocytose dead, dying or viable neurons, which may be beneficial or detrimental in inflammatory, ischaemic and...
BACKGROUND
Microglia are resident brain macrophages that can phagocytose dead, dying or viable neurons, which may be beneficial or detrimental in inflammatory, ischaemic and neurodegenerative brain pathologies. Cell death caused by phagocytosis of an otherwise viable cell is called 'primary phagocytosis' or 'phagoptosis'. Calreticulin (CRT) exposure on the surface of cancer cells can promote their phagocytosis via LRP (low-density lipoprotein receptor-related protein) on macrophages, but it is not known whether this occurs with neurons and microglia.
METHODS
We used primary cultures of cerebellar neurons, astrocytes and microglia to investigate the potential role of CRT/LRP phagocytic signalling in the phagocytosis of viable neurons by microglia stimulated with lipopolysaccharide (LPS) or nanomolar concentrations of amyloid-β peptide1-42 (Aβ). Exposure of CRT on the neuronal surface was investigated using surface biotinylation and western blotting. A phagocytosis assay was also developed using BV2 and PC12 cell lines to investigate CRT/LRP signalling in microglial phagocytosis of apoptotic cells.
RESULTS
We found that BV2 microglia readily phagocytosed apoptotic PC12 cells, but this was inhibited by a CRT-blocking antibody or LRP-blocking protein (receptor-associated protein: RAP). Activation of primary rat microglia with LPS or Aβ resulted in loss of co-cultured cerebellar granule neurons, and this was blocked by RAP or antibodies against CRT or against LRP, preventing all neuronal loss and death. CRT was present on the surface of viable neurons, and this exposure did not change in inflammatory conditions. CRT antibodies prevented microglia-induced neuronal loss when added to neurons, while LRP antibodies prevented neuronal loss when added to the microglia. Pre-binding of CRT to neurons promoted neuronal loss if activated microglia were added, but pre-binding of CRT to microglia or both cell types prevented microglia-induced neuronal loss.
CONCLUSIONS
CRT exposure on the surface of viable or apoptotic neurons appears to be required for their phagocytosis via LRP receptors on activated microglia, but free CRT can block microglial phagocytosis of neurons by acting on microglia. Phagocytosis of CRT-exposing neurons by microglia can be a direct cause of neuronal death during inflammation, and might therefore contribute to neurodegeneration and be prevented by blocking the CRT/LRP pathway.
Topics: Amyloid beta-Peptides; Animals; Calreticulin; Cell Survival; Cells, Cultured; Coculture Techniques; LDL-Receptor Related Proteins; Lipopolysaccharides; Microglia; Neurons; PC12 Cells; Peptide Fragments; Phagocytosis; Rats; Signal Transduction
PubMed: 22889139
DOI: 10.1186/1742-2094-9-196 -
Ultrasound in Medicine & Biology Feb 2007Delayed parenchymal phase images of the liver more than 5 min after IV injection of ultrasound contrast agents are thought to be related to the phagocytosis of contrast...
Delayed parenchymal phase images of the liver more than 5 min after IV injection of ultrasound contrast agents are thought to be related to the phagocytosis of contrast agent microbubbles by macrophages. In this study, we examined whether liver-specific macrophages, Kupffer cells, phagocytosed the microbubbles and whether their elimination affected the delayed parenchymal images of the liver. Phase-contrast microscope observations showed that Kupffer cells phagocytosed various contrast agents in vitro. Among the contrast agents used, 99% of Sonazoid and Optison, and 47% of Levovist were phagocytosed, whereas only 7.3% of SonoVue and 0% of Imavist were phagocytosed. Elimination of Kupffer cells in vivo by gadolinium chloride (GdCl(3)) resulted in decreased intensity of the delayed parenchymal images with Sonazoid and Levovist, while SonoVue showed no changes compared with control. Our findings suggested that Kupffer cells phagocytosed contrast agents and they were responsible for the delayed images of contrast ultrasound in the liver.
Topics: Albumins; Animals; Cells, Cultured; Contrast Media; Ferric Compounds; Fluorocarbons; Gadolinium; Image Enhancement; Iron; Kupffer Cells; Liver; Macrophages; Male; Microbubbles; Microscopy, Phase-Contrast; Oxides; Phagocytosis; Phospholipids; Polysaccharides; Rats; Rats, Wistar; Sulfur Hexafluoride; Ultrasonography
PubMed: 17207907
DOI: 10.1016/j.ultrasmedbio.2006.08.008 -
The Journal of Biological Chemistry Dec 1998MacMARCKS (also known as myristoylated alanine-rich protein kinase C substrate (MARCKS)-related protein) is a member of the MARCKS family of protein kinase C substrates....
MacMARCKS (also known as myristoylated alanine-rich protein kinase C substrate (MARCKS)-related protein) is a member of the MARCKS family of protein kinase C substrates. MacMARCKS contains within it a basic effector domain that contains the serine residues that are phosphorylated by protein kinase C, as well as a calcium/calmodulin and actin-binding site. Two previous reports demonstrated that a macrophage cell line expressing a mutant form of MacMARCKS that lacks the effector domain is defective in phagocytosis and cell adhesion (Zhu, Z., Bao, Z., and Li, J. (1995) J. Biol. Chem. 270, 17652-17655; Li, J., Zhu, Z., and Bao, Z. (1996) J. Biol. Chem. 271, 12985-12990). We report here that macrophages from MacMARCKS null mice phagocytose and spread normally. Thus, although MacMARCKS is recruited to phagosomes, it is not absolutely required for phagocytosis.
Topics: Animals; Calmodulin-Binding Proteins; Cell Line; Intracellular Signaling Peptides and Proteins; Macrophages; Membrane Proteins; Mice; Mice, Knockout; Microfilament Proteins; Phagocytosis
PubMed: 9837946
DOI: 10.1074/jbc.273.50.33619 -
Journal of Microbiology, Immunology,... Jun 2021Shwachman-Bodian-Diamond syndrome (SBDS) protein is widely present in eukaryotes from vertebrates to protozoa. However, there are several variants within species, and...
BACKGROUND/PURPOSE
Shwachman-Bodian-Diamond syndrome (SBDS) protein is widely present in eukaryotes from vertebrates to protozoa. However, there are several variants within species, and previous studies have shown evidence that they may have additional functions. There are two SBDS-related proteins in Acanthamoeba. One is an rRNA metabolism protein of the SBDS family (ACA1_142090), and the other is SBDS (ACA1_204560). Although there is a conserved SBDS domain in the Acanthamoeba SBDS (ACA1_204560; AcSBDS), its function has not been reported. The aims of this study were to characterize the expression of AcSBDS during phagocytosis and encystation.
METHODS
AcSBDS-specific primer was designed to amplify the genomic AcSBDS of Acanthamoeba ATCC-30010. The AcSBDS expression was examined using reverse transcription polymerase chain reaction (RT-PCR) and immunostaining after phagocytosis and encystation treatment.
RESULTS
In this study, we found that the mRNA expression level of AcSBDS increased rapidly and that alternative splice variants were detected during phagocytosis and encystation processes. The results of immunofluorescence staining showed that the AcSBDS proteins accumulated surrounding phagocytosed bacteria.
CONCLUSION
Our results suggest that AcSBDS may not only have ribosomal maturation features but also have cytoskeleton-associated functions related to phagocytosis and encystation.
Topics: Acanthamoeba; Cytoskeleton; Gene Expression; Parasite Encystment; Phagocytosis; Protein Binding; Protozoan Proteins
PubMed: 31882330
DOI: 10.1016/j.jmii.2019.11.003 -
Acta Biologica Et Medica Germanica 1979The ability of insect blood cells to ingest all kinds of synthetic particles and also a wide range of microorganisms in a very short time after injection has up to now...
The ability of insect blood cells to ingest all kinds of synthetic particles and also a wide range of microorganisms in a very short time after injection has up to now been regarded as a phagocytic function without any humoral mediators. In a phagocytosis model with latex beads and nonhagocytosable cells of Bacillus thuringiensis subtoxicus, we are able to demonstrate the existence of lymphokine-like factors, which intervene in cellular defence reactions of insect. The following results were obtained: 1. Immediately after injection of latex beads, normally non-phagocytosable cells of Bacillus thuringiensis subtoxicus are phagocytosed. 2. Cell-free haemolymph of larvae of Galleria mellonella previously injected with latex beads, stimulates in new larvae phagocytosis of Bacillus thuringiensis subtoxicus after transfusion. 3. The fractionation of homogenates of latex-treated larvae on Sephadex G 50 shows two fractions which stimulate phagocytosis. We suppose that the appearance of these phagocytosis-stimulating factors is the result of a successful recognition of foreign material.
Topics: Animals; Bacillus thuringiensis; Larva; Latex; Lepidoptera; Microspheres; Phagocytosis
PubMed: 543373
DOI: No ID Found