Macrophages exist in most tissues and play a variety of functions in vertebrates.Teleost fish species are found in most aquatic environments throughout the world and are quite diverse for a group of vertebrate animals...Macrophages exist in most tissues and play a variety of functions in vertebrates.Teleost fish species are found in most aquatic environments throughout the world and are quite diverse for a group of vertebrate animals.Due to whole genome duplication and en vironme ntal adaptati on,teleost monocytes/macrophages possess a variety of different functions and modulations compared with those of mammals.A deeper understanding of teleost monocytes/macrophages in the immune system will not only help develop teleost-specific methods of disease prevention but will also help improve our understanding of the various immune mechanisms in mammals.In this review,we summarize the differences in polarizati on and phagocytosis of teleost and mammalian macrophages to improve our understanding of the various immune mechanisms in vertebrates.展开更多
Apoptosis is a widespread phenomenon that occurs in the brain in both physiological and pathological conditions. Dead cells must be quickly removed to avoid the further toxic effects they exert in the parenchyma, a pr...Apoptosis is a widespread phenomenon that occurs in the brain in both physiological and pathological conditions. Dead cells must be quickly removed to avoid the further toxic effects they exert in the parenchyma, a process executed by microglia, the brain professional phagocytes. Although phagocytosis is critical to maintain tissue homeostasis, it has long been either overlooked or indirectly assessed based on microglial morphology, expression of classical activation markers, or engulfment of artificial phagocytic targets in vitro. Nevertheless, these indirect methods present several limitations and, thus, direct observation and quantification of microglial phagocytosis is still necessary to fully grasp its relevance in the diseased brain. To overcome these caveats and obtain a comprehensive, quantitative picture of microglial phagocytosis we have developed a novel set of parameters. These parameters have allowed us to identify the different strategies utilized by microglia to cope with apoptotic challenges induced by excitotoxicity or inflammation. In contrast, we discovered that in mouse and human epilepsy microglia failed to find and engulf apoptotic cells, resulting in accumulation of debris and inflammation. Herein, we advocate that the efficiency of microglial phagocytosis should be routinely tested in neurodegenerative and neurological disorders, in order to determine the extent to which it contributes to apoptosis and inflammation found in these conditions. Finally, our findings point towards enhancing microglial phagocytosis as a novel therapeutic strategy to control tissue damage and inflammation, and accelerate recovery in brain diseases.展开更多
AIM:To investigate if the presence of relevant genetic polymorphisms has effect on the effectual clearance of bacteria by monocytes and granulocytes in patients with Crohn’s disease(CD).METHODS:In this study,we asses...AIM:To investigate if the presence of relevant genetic polymorphisms has effect on the effectual clearance of bacteria by monocytes and granulocytes in patients with Crohn’s disease(CD).METHODS:In this study,we assessed the differential responses in phagocytosis by measuring the phagocytic activity and the percentage of active phagocytic monocytes and granulocytes in inflammatory bowel disease patients as well as healthy controls.As both autophagy related like 1(ATG16L1)and immunityrelated guanosine triphosphatase gene are autophagy genes associated with CD and more recently nucleo-tide-binding ligomerization domain-containing protein2(NOD2)has been identified as a potent inducer of autophagy we genotyped the patients for these variants and correlated this to the phagocytic reaction.The genotyping was done with restriction fragment length polymorphisms analysis and the phagocytosis was determined with the pHrodo?Escherichia coli Bioparticles Phagocytosis kit for flowcytometry.RESULTS:In this study,we demonstrate that analysis of the monocyte and granulocyte populations of patients with CD and ulcerative colitis showed a comparable phagocytic activity(ratio of mean fluorescence intensity)between the patient groups and the healthy controls.CD patients show a significantly higher phagocytic capacity(ratio mean percentage of phagocytic cells)compared to healthy controls(51.91%±2.85%vs 37.67%±7.06%,P=0.05).The extend of disease was not of influence.However,variants of ATG16L1(WT:2.03±0.19 vs homozygoot variant:4.38±0.37,P<0.009)as well as NOD2(C-ins)(heterozygous variant:42.08±2.94 vs homozygous variant:75.58±4.34(P=0.05)are associated with the phagocytic activity in patients with CD.CONCLUSION:Monocytes of CD patients show enhanced phagocytosis associated with the presence of ATG16L1 and NOD2 variants.This could be part of the pathophysiological mechanism resulting in the disease.展开更多
AIM: Age-related macular degeneration (AMD) is a multifactorial disease and a prevalent cause of visual impairment in developed countries. Many studies suggest that age-related maculopathy susceptibility 2 (ARMS2) is ...AIM: Age-related macular degeneration (AMD) is a multifactorial disease and a prevalent cause of visual impairment in developed countries. Many studies suggest that age-related maculopathy susceptibility 2 (ARMS2) is a second major susceptibility gene for AMD. At present, there is no functional information on this gene. Therefore, the purpose of the present study was to detect the expression of ARMS2 in retinal pigment epithelium (RPE) cells and to investigate the effect of ARMS2 on the phagocytosis function of RPE cells. · METHODS: Immunofluorescence and reverse transcriptase PCR were used to demonstrate the presence and location of ARMS2 in ARPE-19 (human retinal pigment epithelial cell line, ATCC, catalog No.CRL-2302) cells. siRNA was used to knock down ARMS2 mRNA, and the effects of the knockdown on the phagocytosis function of the ARPE-19 cells were evaluated via Fluorescence Activated Cell Sorting (FACS). · RESULTS: ARMS2 was present in ARPE-19 cells, localized in the cytosol of the perinuclear region. The expression of ARMS2 mRNA (messenger RNA) in ARPE-19 cells transfected with ARMS2-siRNA (small interfering RNA, 0.73±0.08) was decreased compared with normal cells (1.00±0.00) or with cells transfected with scrambled siRNA (0.95±0.13) (P<0.05). After incubation of RPE cells with a latex beads medium for 12, 18, or 24 hours, the fluorescence intensities were 38.04±1.02, 68.92±0.92, and 78.00±0.12 in the ARMS2-siRNA-transfected groups, respectively, and 77.98±5.43, 94.87±0.60, and 98.30±0.11 in the scrambled siRNA-transfected groups, respectively. The fluorescent intensities of the same time points in the two groups were compared using Student's t-test, and the p values were all less than 0.001 at the three different time points. · CONCLUSION: There is endogenous expression of ARMS2 in ARPE-19 cells. ARMS2 plays a role in the phagocytosis function of RPE cells, and this role may be one of the mechanisms that participates in the development of AMD.展开更多
To investigate phagocytosis, peritoneal-resident and J774.1 macrophages were incubated with fluorescent polystyrene microspheres measuring 1.0 μm in diamter at 200 particles per cell. The amount of phagocytized micro...To investigate phagocytosis, peritoneal-resident and J774.1 macrophages were incubated with fluorescent polystyrene microspheres measuring 1.0 μm in diamter at 200 particles per cell. The amount of phagocytized microspheres increased with incubation time, and both cell types had similar phagocytic activity. Further, we investigated the phagocytosis of different sizes of microspheres by J774.1 macrophages. To adequately evaluate phagocytosis, varying amounts of different sizes of microspheres were added to J774.1 cells, and their phagocytic activities were evaluated. When the microspheres were added at a density of 20 particles per cell, few small microspheres (<1.0 μm in diameter) were phagocytized. This result suggested that their low amount caused difficulty in evaluating phagocytosis. In contrast, when the same variety of microspheres was added at a density of 200 particles per cell, phagocytosis of large microspheres (>3 μm in diameter) could not be evaluated because of cytotoxicity. Thus, the amount of different sizes of microspheres added is important for precisely evaluating phagocytic activity. When the amount of different sizes of microspheres added was standardized to provide a set amount of total surface area, phagocytosis of these microspheres could be adequately evaluated and compared. To determine the effects of phagocytosis on cell viability and proliferation, cells incubated with different sizes of microspheres were assayed using a cell counting kit. We found that phagocytosis had no effect on cell viability or proliferation and was independent of particle size. Furthermore, cells already phagocytized microspheres retained their phagocytic activity.展开更多
Objective:To investigate the effects of 20 methanolic extracts from Malaysian selected plants on CD18/11 a expression and phagocytosis activity of leukocytes using flow cytometry analysis.Methods:The effects of methan...Objective:To investigate the effects of 20 methanolic extracts from Malaysian selected plants on CD18/11 a expression and phagocytosis activity of leukocytes using flow cytometry analysis.Methods:The effects of methanolic extracts on CD18/11 a expression and phagocytosis of leukocytes were measured by labelling the cells with CD18-fluorescein isolhiocyanaie and ingestion labelled with Escherichia coli-fluorescein isothiocyanate and then analyzed using flow cytometer.Results:About 12 out of 20 methanolic extracts of selected Malaysian medicinal plants significantly(P≤0.05) inhibited the CD18/1 la expression of leukocytes at both concentrations of 6.25 μg/mL and 100 μg/mL in dose dependent manner.The most active inhibitory was shown in Citrus aurantifolia(Christm.) Swingle and Alpinia galangal(L.) Willd.at dosage 100ug/mL.Moreover,the Orthosiphon aristatus(Blume) Miq(O.aristatus).showed the highest stimulatory activity at the concentration of 100 μg/mL.Other than that,four plant extracts significantly(P<0.05) rose the phagocytosis activities of leukocytes in dose dependent manner.However,Annona muricata L.and O.aristatus showed the highest stimulated activities at the 100 pg/mL concentration.Conclusions:The results suggest that methanolic extracts of Cirrus aurantifolia.Alpinia gaiangal,O.aristatus and Annona muricata are able to modulate innate immune system and can potentially be recognized as therapeutic agents for modulating immune system.展开更多
Background: Interferon-γ(IFN-γ) is critical for innate and adaptive immunity against viral and bacterial infections. IFN-γ reportedly affects the phagocytic ability of monocytes and macrophages as well as regulates...Background: Interferon-γ(IFN-γ) is critical for innate and adaptive immunity against viral and bacterial infections. IFN-γ reportedly affects the phagocytic ability of monocytes and macrophages as well as regulates pituitary function in humans and mice. The present study analyzed the impact of IFN-γ on monocyte and macrophage phagocytosis, production performance, and pituitary function in vivo and in vitro(in dwarf chickens). IFN-γ was injected into dwarf chickens through a vein, and then, the laying rate, average egg weight, and levels of follicle-stimulating hormone(FSH) and IFN-γ were measured in treatment and control groups. For the in vitro experiment, the pituitary tissues were supplemented with IFN-γ, and the m RNA expression levels of follicle-stimulating hormone beta subunit(FSH-β), interferon gamma receptor 1(IFNGR1),and interferon gamma receptor 2(IFNGR2) in the pituitary were assessed.Results: Monocyte and macrophage phagocytosis product(PP) was decreased by IFN-γ treatment in a dose-dependent manner in vitro. In the in vivo experiment, the level of IFN-γ in the treatment group was higher than that in the control group at 7 d(P < 0.05), 14 d(P < 0.01), and 21 d(P < 0.01) post-injection.Compared with the control group, monocyte and macrophage PP was lower in the treatment group after injection(P < 0.01). The laying rate was higher in the treatment group than in the control group at 2 and3 wk post-injection(P < 0.05). There was a significant difference between the treatment and control groups in the levels of FSH at 1, 3, 7, and 14 d post-injection(P < 0.01). In the in vitro experiment, increased m RNA expression levels of FSH-β, IFNGR1, and IFNGR2 were observed in the treatment group after stimulation with100 U/m L IFN-γ for 24 h compared to those in the control group(P < 0.05).Conclusions: IFN-γ inhibited the phagocytosis of monocytes and macrophages; up-regulated the m RNA expression levels of the FSH-β, IFNGR1, and IFNGR2; enhanced the secretion of FSH; and improved the laying rate. IFN-γ might be an important regulator in the trade-off between the immune effect and production performance in dwarf chickens.展开更多
BACKGROUND Type Ⅰ diabetes(T1D)is characterized by insulin loss caused by inflammatory cells that excessively infiltrate and destroy the pancreas,resulting in dysregulation of tissue homeostasis,mechanobiological pro...BACKGROUND Type Ⅰ diabetes(T1D)is characterized by insulin loss caused by inflammatory cells that excessively infiltrate and destroy the pancreas,resulting in dysregulation of tissue homeostasis,mechanobiological properties,and the immune response.The streptozotocin(STZ)-induced mouse model exhibits multiple features of human T1D and enables mechanistic analysis of disease progression.However,the relationship between the mechanochemical signaling regulation of STZ-induced T1D and macrophage migration and phagocytosis is unclear.AIM To study the mechanochemical regulation of STZ-induced macrophage response on pancreatic beta islet cells to gain a clearer understanding of T1D.METHODS We performed experiments using different methods.We stimulated isolated pancreatic beta islet cells with STZ and then tested the macrophage migration and phagocytosis.RESULTS In this study,we discovered that the integrin-associated surface factor CD47 played a critical role in immune defense in the STZ-induced T1D model by preventing pancreatic beta islet inflammation.In comparison with healthy mice,STZ-treated mice showed decreased levels of CD47 on islet cells and reduced interaction of CD47 with signal regulatory proteinα(SIRPα),which negatively regulates macrophage-mediated phagocytosis.This resulted in weakened islet cell immune defense and promoted macrophage migration and phagocytosis of target inflammatory cells.Moreover,lipopolysaccharide-activated human acute monocytic leukemia THP-1 cells also exhibited enhanced phagocytosis in the STZ-treated islets,and the aggressive attack of the inflammatory islets correlated with impaired CD47-SIRPαinteractions.In addition,CD47 overexpression rescued the pre-labeled targeted cells.CONCLUSION This study indicates that CD47 deficiency promotes the migration and phagocytosis of macrophages and provides mechanistic insights into T1D by associating the interactions between membrane structures and inflammatory disease progression.展开更多
The effect of transforming growth factor β 2 (TGF β 2) on phagocytosis in bovine trabecular meshwork cells in vitro was investigated. After the cultured bovine trabecular meshwork cells were treated with 0 ng/ml, 0....The effect of transforming growth factor β 2 (TGF β 2) on phagocytosis in bovine trabecular meshwork cells in vitro was investigated. After the cultured bovine trabecular meshwork cells were treated with 0 ng/ml, 0.32 ng/ml, 1 ng/ml, 3.2 ng/ml TGF β 2 for 24 h, latex beads were added into the incubation medium, and the numbers of the latex beads in 20 adjacent cells were counted under a microscope 24 h later, after treatment with Wright’s stain. Our results showed that the average numbers of the latex beads in the trabecular meshwork cells treated with TGF β 2 of different concentrations were 53.1±1.7 beads/cell, 56.4±2.9 beads/cell and 77.9±6.5 beads/cell respectinvely, in comparison with 45.5±3.3 beads/cell of the control group. TGF β 2 significantly increased the number of the latex beads phagocytosed by cultured bovine trabecular meshwork cells in a dose dependent manner. TGF β 2 could promote the phagocytosis of bovine trabecular meshwork cells in vitro . It may be involved in the cellularity decrease of the trabecular meshwork in the patients of primary open angle glaucoma through promoting the phagocytosis of trabecular meshwork cells.展开更多
The purpose of this study was to explore the effects of recombinant human intestinal alkaline phosphatase(recIAP) on human neutrophils in vitro, and the migration, phagocytosis, apoptosis in presence and absence of LP...The purpose of this study was to explore the effects of recombinant human intestinal alkaline phosphatase(recIAP) on human neutrophils in vitro, and the migration, phagocytosis, apoptosis in presence and absence of LPS. In this study, freshly extracted human neutrophils were used to establish an inflammatory cell model, and the control group, recIAP group, LPS group and recIAP +LPS group were set up to stimulate the model. The migration of neutrophils was detected by agarose gel drop method. Fluorescent particles and fluorescent probes were added to different treatment groups, and the phagocytic rate of neutrophils and the release of reactive oxygen species(ROS) from neutrophils were detected by flow cytometry. The apoptosis rate of neutrophils was detected by flow cytometry according to Annexin V-FITC apoptosis detection kit. The results showed that regardless of the presence or absence of LPS, recIAP could inhibit the migration of neutrophils, phagocytosis and the release of ROS. In addition, recIAP could weaken the inhibitory effect of LPS on neutrophils apoptosis.展开更多
Living systems have to constantly counter micro-or- ganisms which seek parasitic existence by extracting nutrition (amino acids) from the host. Phagocytosis is the ingestion of micro-creatures by certain cells of livi...Living systems have to constantly counter micro-or- ganisms which seek parasitic existence by extracting nutrition (amino acids) from the host. Phagocytosis is the ingestion of micro-creatures by certain cells of living systems for counter nutrition (breakdown of the micro-creature into basic components) as part of cellular adaptive immune response. These particular cells are called phagocytes, all of which are different types of white blood cells or their derivatives. Phagocytes are activated by certain components of the micro-creatures which act as an antigen, generating an- tibody secretion by the phagocyte. This paper develops a digital CMOS circuit model of phagocytosis: the immune response biochemical pathway of a pha- gocyte. A micro-sequenced model has been developed where the different stages in phagocytosis are modeled as different states clocked by circadian time intervals. The model converts the bio-chemical immune system digestive pathway into a cascade of CMOS multi-step logical transformations from micro-crea- ture ingestion to the secretion of indigestible residuals. This modeling technique leads to the understanding of cellular immune deficiency diseases of living systems in the form of logical (electrical) faults in a circuit.展开更多
Neutrophils are the most important circulating phagocytes. Circulating mono-cytes and precursors of tissue macrophages also have the ability to phagocytize. Pidotimod (ADIMODTM) exerts immunostimulatory and immunoregu...Neutrophils are the most important circulating phagocytes. Circulating mono-cytes and precursors of tissue macrophages also have the ability to phagocytize. Pidotimod (ADIMODTM) exerts immunostimulatory and immunoregulatory effects through the stimulation and regulation of cellular immune responses by lymphocytes Canine herpesvirus (CHV) mainly affect puppies between the first and second weeks of age, causing high morbidity in the litter. To date, there is only one commercial vaccine in Europe to prevent disease. In this work, inactivated CHV cultures were inoculated in rabbits, adsorbed and not adsorbed to chitosan nanoparticles. Phagocytosis in the presence or absence of specific antibodies was measured. Response of virus neutralizing antibodies was also evaluated. AdimodTM enhanced the nonspecific and specific phagocytotic response. The association of the virus to the nanoparticles increased the phagocytic ability of blood cells;however, AdimodTM alone had a greater effect on phagocytic activity and generated a stronger immune response that corresponded to the increased phagocytosis (p TM was used.展开更多
Introduction: The existence of receptor-mediated endocytosis (RME) means that selectivity and selectivity occurs in capturing macromolecules. Protein kinase C (PKC) which can be expressed by almost all cells are prote...Introduction: The existence of receptor-mediated endocytosis (RME) means that selectivity and selectivity occurs in capturing macromolecules. Protein kinase C (PKC) which can be expressed by almost all cells are proteins important in signal transduction groove that plays a role in a number of cell activity, e.g. phagocytosis. Aims: The purpose of this study is to determine the expression of RME after modulating the PKC which is characterized by the number of Candida albicans cells attached to the surface of macrophages. Methods: Peritoneal macrophages cultured BALB/c mice are treated with PMA and/or bisindolylmaleimides of providing levels of 5 ng/ml to 100 ng/ml for 10 minutes. Then immediately insert Candida albicans and observe every 30 minutes for 120 minutes. The research design used the same subject. Data collected in the form of number of Candida albicans cells attached to the surface of macrophages are analyzed with ANOVA statistical test (one way) to show the differences between treatments. Results: The test shows statistically significant difference in the number of Candida albicans cells attached to the surface of macrophages after administration of various levels of PMA (p 0.001). The higher level of PMA is given, the more active the PKC is, the more RME are formed, the more Candida albicans cells attached to the surface of macrophages. Another result shows statistically significant difference in the number of Candida albicans cells attached to the surface of macrophages after administration of various levels of bisindolylmaleimides (p 0.001). The higher level of bisindolylmaleimide is given, the less active PKC is, and the less RME are formed, the less Candida albicans cells attached to the surface of macrophages. Conclusion: Research shows that activator PKC (PMA) can increase the expression of RME on macrophages. Another research shows that inhibitor PKC (bisindolylmaleimides) can decrease the expression of RME on macrophages.展开更多
The defense system of teleost fish organized on innate and adaptive immunity protects them against a wide variety of pathogenic microorganisms in the aquatic environment.Phagocytosis is one of the most effective defen...The defense system of teleost fish organized on innate and adaptive immunity protects them against a wide variety of pathogenic microorganisms in the aquatic environment.Phagocytosis is one of the most effective defense strategies against microbial challenge mainly performed by classical‘professional’phagocytes(including monocytes,macrophages and granulocytes).They contain,kill and process the internalized pathogens for antigen presentation by providing antigenic ligands to initiate activation and clonal expansion of T and B cells,which bridge the innate and adaptive immunity.The discovery of phagocytic B cells in teleost fish has broken the paradigm that primary vertebrate B cells are lack of phagocytosis of particulates,as well as led to the investigation of phagocytic activity of mammalian B-1 B cells.The active phagocytic,microbicidal capabilities and antigen presentation in teleost phagocytic B cell have demonstrated to be similar as professional phagocytes,providing a potential impact on development of new vaccination strategies to prevent and control infectious diseases.In this review,we aim to address current progress on the antimicrobial role of phagocytic B cells in teleost fish by comparing it with other professional phagocytes and mammalian B-1 B cells,and provide the application prospect of phagocytic B cells in developing vaccines as well as the prevention of fish diseases.展开更多
O-GlcNAcylation is a post-translational modification that serves as a cellular nutrient sensor and participates in multiple physiological and pathological processes.However,it remains uncertain whether O-GlcNAcylation...O-GlcNAcylation is a post-translational modification that serves as a cellular nutrient sensor and participates in multiple physiological and pathological processes.However,it remains uncertain whether O-GlcNAcylation is involved in the regulation of phagocytosis.Here,we demonstrate a rapid increase in protein OGlcNAcylation in response to phagocytotic stimuli.Knockout of the O-GlcNAc transferase or pharmacological inhibition of O-GlcNAcylation dramatically blocks phagocytosis,resulting in the disruption of retinal structure and function.Mechanistic studies reveal that the O-GlcNAc transferase interacts with Ezrin,a membrane-cytoskeleton linker protein,to catalyze its O-GlcNAcylation.Our data further show that Ezrin OGlcNAcylation promotes its localization to the cell cortex,thereby stimulating the membrane-cytoskeleton interaction needed for efficient phagocytosis.These findings identify a previously unrecognized role for protein O-GlcNAcylation in phagocytosis with important implications in both health and diseases.展开更多
In sepsis, macrophage bacterial phagocytosis is impaired, but the mechanism is not well elucidated. Extracellular cold-inducible RNA-binding protein (eCIRP) is a damage-associated molecular pattern that causes inflamm...In sepsis, macrophage bacterial phagocytosis is impaired, but the mechanism is not well elucidated. Extracellular cold-inducible RNA-binding protein (eCIRP) is a damage-associated molecular pattern that causes inflammation. However, whether eCIRP regulates macrophage bacterial phagocytosis is unknown. Here, we reported that the bacterial loads in the blood and peritoneal fluid were decreased in CIRP^(−/−) mice and anti-eCIRP Ab-treated mice after sepsis. Increased eCIRP levels were correlated with decreased bacterial clearance in septic mice. CIRP−/− mice showed a marked increase in survival after sepsis. Recombinant murine CIRP (rmCIRP) significantly decreased the phagocytosis of bacteria by macrophages in vivo and in vitro. rmCIRP decreased the protein expression of actin-binding proteins, ARP2, and p-cofilin in macrophages. rmCIRP significantly downregulated the protein expression of βPIX, a Rac1 activator. We further demonstrated that STAT3 and βPIX formed a complex following rmCIRP treatment, preventing βPIX from activating Rac1. We also found that eCIRP-induced STAT3 phosphorylation was required for eCIRP’s action in actin remodeling. Inhibition of STAT3 phosphorylation prevented the formation of the STAT3-βPIX complex, restoring ARP2 and p-cofilin expression and membrane protrusion in rmCIRP-treated macrophages. The STAT3 inhibitor stattic rescued the macrophage phagocytic dysfunction induced by rmCIRP. Thus, we identified a novel mechanism of macrophage phagocytic dysfunction caused by eCIRP, which provides a new therapeutic target to ameliorate sepsis.展开更多
Germinal matrix hemorrhage is one of the leading causes of morbidity,mortality,and acquired infantile hydrocephalus in preterm infants in the United States,with little progress made in its clinical management.Blood cl...Germinal matrix hemorrhage is one of the leading causes of morbidity,mortality,and acquired infantile hydrocephalus in preterm infants in the United States,with little progress made in its clinical management.Blood clots have been shown to elicit secondary brain injury after germinal matrix hemorrhage,by disrupting normal cerebrospinal fluid circulation and absorption after germinal matrix hemorrhage causing post-hemorrhagic hydrocephalus development.Current evidence suggests that rapid hematoma resolution is necessary to improve neurological outcomes after hemorrhagic stroke.Various articles have demonstrated the beneficial effects of stimulating the polarization of microglia cells into the M2 phenotype,as it has been suggested that they play an essential role in the rapid phagocytosis of the blood clot after hemorrhagic models of stroke.N-formyl peptide receptor 2(FPR2),a G-protein-coupled receptor,has been shown to be neuroprotective after stroke.FPR2 activation has been associated with the upregulation of phagocytic macrophage clearance,yet its mechanism has not been fully explored.Recent literature suggests that FPR2 may play a role in the stimulation of scavenger receptor CD36.Scavenger receptor CD36 plays a vital role in microglia phagocytic blood clot clearance after germinal matrix hemorrhage.FPR2 has been shown to phosphorylate extracellular-signal-regulated kinase 1/2(ERK1/2),which then promotes the transcription of the dual-specificity protein phosphatase 1(DUSP1)gene.In this review,we present an intrinsic outline of the main components involved in FPR2 stimulation and hematoma resolution after germinal matrix hemorrhage.展开更多
Preclinical and clinical studies have shown that microglia and macrophages participate in a multiphasic brain damage repair process following intracerebral hemorrhage.The E26 transformation-specific sequence-related t...Preclinical and clinical studies have shown that microglia and macrophages participate in a multiphasic brain damage repair process following intracerebral hemorrhage.The E26 transformation-specific sequence-related transcription factor Spi1 regulates microglial/macrophage commitment and maturation.However,the effect of Spi1 on intracerebral hemorrhage remains unclear.In this study,we found that Spi1 may regulate recovery from the neuroinflammation and neurofunctional damage caused by intracerebral hemorrhage by modulating the microglial/macrophage transcriptome.We showed that high Spi1expression in microglia/macrophages after intracerebral hemorrhage is associated with the activation of many pathways that promote phagocytosis,glycolysis,and autophagy,as well as debris clearance and sustained remyelination.Notably,microglia with higher levels of Soil expression were chara cterized by activation of pathways associated with a variety of hemorrhage-related cellular processes,such as complement activation,angiogenesis,and coagulation.In conclusion,our results suggest that Spi1 plays a vital role in the microglial/macrophage inflammatory response following intracerebral hemorrhage.This new insight into the regulation of Spi1 and its target genes may advance our understanding of neuroinflammation in intracerebral hemorrhage and provide therapeutic targets for patients with intracerebral hemorrhage.展开更多
The mechanism of sphingosine-1-phosphate(S1P)-mediated phagocytosis remains unknown.Here,we found that S1P or FTY720(an analog of S1P)promoted microglial phagocytosis in stroke independent of S1PRs.First,we used compu...The mechanism of sphingosine-1-phosphate(S1P)-mediated phagocytosis remains unknown.Here,we found that S1P or FTY720(an analog of S1P)promoted microglial phagocytosis in stroke independent of S1PRs.First,we used computer simulation of molecular docking to predict that S1P might be a ligand for triggering receptor expressed on myeloid cells 2(TREM2).Next,microscale thermophoresis(MST),surface plasmon resonance(SPR)and liquid chromatography–tandem mass spectrometry(LC–MS/MS)were performed to reveal that S1P was a novel TREM2 ligand.Then,we confirmed the pro-phagocytosis of S1P targeting in Trem2-Dap12 transfected CHO cells and TREM2 knockdown microglia.Point mutation analysis showed that D104 was the critical binding residue.Trem2^(−/−)mice were used to demonstrate the role of S1P-induced phagocytosis targeting on TREM2 in protecting against ischemic brain injury.Finally,further studies revealed that apolipoprotein E(APOE)loaded with S1P was released by microglia and bound to apoptotic neurons via LDL receptor related protein 1B(LRP1B)and thereby induced microglia to phagocytose apoptotic neurons.Overall,the present work reveals for the first time that S1P acts as a novel endogenous ligand of TREM2 to effectively promote microglial phagocytosis.Our findings provide a new lead compound for developing immunomodulator targeting on TREM2.展开更多
基金supported by the National Natural Science Foundation of China(31772876,41776151)Natural Science Foundation of Zhejiang Province(LZ18C190001,LR18C040001)+1 种基金Scientific Innovation Team Project of Ningbo(2015C110018)K.C.Wong Magna Fund in Ningbo University
文摘Macrophages exist in most tissues and play a variety of functions in vertebrates.Teleost fish species are found in most aquatic environments throughout the world and are quite diverse for a group of vertebrate animals.Due to whole genome duplication and en vironme ntal adaptati on,teleost monocytes/macrophages possess a variety of different functions and modulations compared with those of mammals.A deeper understanding of teleost monocytes/macrophages in the immune system will not only help develop teleost-specific methods of disease prevention but will also help improve our understanding of the various immune mechanisms in mammals.In this review,we summarize the differences in polarizati on and phagocytosis of teleost and mammalian macrophages to improve our understanding of the various immune mechanisms in vertebrates.
基金supported by grants from the Spanish Ministry of Economy and Competitiveness with FEDER funds to AS(BFU2015-66689,RYC-2013-12817)OA is recipient of a predoctoral fellowship from the Basque GovernmentIDA is recipient of a predoctoral fellowship from the University of the Basque Country EHU/UPV
文摘Apoptosis is a widespread phenomenon that occurs in the brain in both physiological and pathological conditions. Dead cells must be quickly removed to avoid the further toxic effects they exert in the parenchyma, a process executed by microglia, the brain professional phagocytes. Although phagocytosis is critical to maintain tissue homeostasis, it has long been either overlooked or indirectly assessed based on microglial morphology, expression of classical activation markers, or engulfment of artificial phagocytic targets in vitro. Nevertheless, these indirect methods present several limitations and, thus, direct observation and quantification of microglial phagocytosis is still necessary to fully grasp its relevance in the diseased brain. To overcome these caveats and obtain a comprehensive, quantitative picture of microglial phagocytosis we have developed a novel set of parameters. These parameters have allowed us to identify the different strategies utilized by microglia to cope with apoptotic challenges induced by excitotoxicity or inflammation. In contrast, we discovered that in mouse and human epilepsy microglia failed to find and engulf apoptotic cells, resulting in accumulation of debris and inflammation. Herein, we advocate that the efficiency of microglial phagocytosis should be routinely tested in neurodegenerative and neurological disorders, in order to determine the extent to which it contributes to apoptosis and inflammation found in these conditions. Finally, our findings point towards enhancing microglial phagocytosis as a novel therapeutic strategy to control tissue damage and inflammation, and accelerate recovery in brain diseases.
文摘AIM:To investigate if the presence of relevant genetic polymorphisms has effect on the effectual clearance of bacteria by monocytes and granulocytes in patients with Crohn’s disease(CD).METHODS:In this study,we assessed the differential responses in phagocytosis by measuring the phagocytic activity and the percentage of active phagocytic monocytes and granulocytes in inflammatory bowel disease patients as well as healthy controls.As both autophagy related like 1(ATG16L1)and immunityrelated guanosine triphosphatase gene are autophagy genes associated with CD and more recently nucleo-tide-binding ligomerization domain-containing protein2(NOD2)has been identified as a potent inducer of autophagy we genotyped the patients for these variants and correlated this to the phagocytic reaction.The genotyping was done with restriction fragment length polymorphisms analysis and the phagocytosis was determined with the pHrodo?Escherichia coli Bioparticles Phagocytosis kit for flowcytometry.RESULTS:In this study,we demonstrate that analysis of the monocyte and granulocyte populations of patients with CD and ulcerative colitis showed a comparable phagocytic activity(ratio of mean fluorescence intensity)between the patient groups and the healthy controls.CD patients show a significantly higher phagocytic capacity(ratio mean percentage of phagocytic cells)compared to healthy controls(51.91%±2.85%vs 37.67%±7.06%,P=0.05).The extend of disease was not of influence.However,variants of ATG16L1(WT:2.03±0.19 vs homozygoot variant:4.38±0.37,P<0.009)as well as NOD2(C-ins)(heterozygous variant:42.08±2.94 vs homozygous variant:75.58±4.34(P=0.05)are associated with the phagocytic activity in patients with CD.CONCLUSION:Monocytes of CD patients show enhanced phagocytosis associated with the presence of ATG16L1 and NOD2 variants.This could be part of the pathophysiological mechanism resulting in the disease.
基金Supported by National Natural Science Foundation of China(No.30901637)Qingdao Sci-Tec Bureau, China(No.08-2-1-3-nsh)
文摘AIM: Age-related macular degeneration (AMD) is a multifactorial disease and a prevalent cause of visual impairment in developed countries. Many studies suggest that age-related maculopathy susceptibility 2 (ARMS2) is a second major susceptibility gene for AMD. At present, there is no functional information on this gene. Therefore, the purpose of the present study was to detect the expression of ARMS2 in retinal pigment epithelium (RPE) cells and to investigate the effect of ARMS2 on the phagocytosis function of RPE cells. · METHODS: Immunofluorescence and reverse transcriptase PCR were used to demonstrate the presence and location of ARMS2 in ARPE-19 (human retinal pigment epithelial cell line, ATCC, catalog No.CRL-2302) cells. siRNA was used to knock down ARMS2 mRNA, and the effects of the knockdown on the phagocytosis function of the ARPE-19 cells were evaluated via Fluorescence Activated Cell Sorting (FACS). · RESULTS: ARMS2 was present in ARPE-19 cells, localized in the cytosol of the perinuclear region. The expression of ARMS2 mRNA (messenger RNA) in ARPE-19 cells transfected with ARMS2-siRNA (small interfering RNA, 0.73±0.08) was decreased compared with normal cells (1.00±0.00) or with cells transfected with scrambled siRNA (0.95±0.13) (P<0.05). After incubation of RPE cells with a latex beads medium for 12, 18, or 24 hours, the fluorescence intensities were 38.04±1.02, 68.92±0.92, and 78.00±0.12 in the ARMS2-siRNA-transfected groups, respectively, and 77.98±5.43, 94.87±0.60, and 98.30±0.11 in the scrambled siRNA-transfected groups, respectively. The fluorescent intensities of the same time points in the two groups were compared using Student's t-test, and the p values were all less than 0.001 at the three different time points. · CONCLUSION: There is endogenous expression of ARMS2 in ARPE-19 cells. ARMS2 plays a role in the phagocytosis function of RPE cells, and this role may be one of the mechanisms that participates in the development of AMD.
文摘To investigate phagocytosis, peritoneal-resident and J774.1 macrophages were incubated with fluorescent polystyrene microspheres measuring 1.0 μm in diamter at 200 particles per cell. The amount of phagocytized microspheres increased with incubation time, and both cell types had similar phagocytic activity. Further, we investigated the phagocytosis of different sizes of microspheres by J774.1 macrophages. To adequately evaluate phagocytosis, varying amounts of different sizes of microspheres were added to J774.1 cells, and their phagocytic activities were evaluated. When the microspheres were added at a density of 20 particles per cell, few small microspheres (<1.0 μm in diameter) were phagocytized. This result suggested that their low amount caused difficulty in evaluating phagocytosis. In contrast, when the same variety of microspheres was added at a density of 200 particles per cell, phagocytosis of large microspheres (>3 μm in diameter) could not be evaluated because of cytotoxicity. Thus, the amount of different sizes of microspheres added is important for precisely evaluating phagocytic activity. When the amount of different sizes of microspheres added was standardized to provide a set amount of total surface area, phagocytosis of these microspheres could be adequately evaluated and compared. To determine the effects of phagocytosis on cell viability and proliferation, cells incubated with different sizes of microspheres were assayed using a cell counting kit. We found that phagocytosis had no effect on cell viability or proliferation and was independent of particle size. Furthermore, cells already phagocytized microspheres retained their phagocytic activity.
基金Supported by Ministry of Higher Education.Malaysia(Grant No.GUP-SK-07-23-042)
文摘Objective:To investigate the effects of 20 methanolic extracts from Malaysian selected plants on CD18/11 a expression and phagocytosis activity of leukocytes using flow cytometry analysis.Methods:The effects of methanolic extracts on CD18/11 a expression and phagocytosis of leukocytes were measured by labelling the cells with CD18-fluorescein isolhiocyanaie and ingestion labelled with Escherichia coli-fluorescein isothiocyanate and then analyzed using flow cytometer.Results:About 12 out of 20 methanolic extracts of selected Malaysian medicinal plants significantly(P≤0.05) inhibited the CD18/1 la expression of leukocytes at both concentrations of 6.25 μg/mL and 100 μg/mL in dose dependent manner.The most active inhibitory was shown in Citrus aurantifolia(Christm.) Swingle and Alpinia galangal(L.) Willd.at dosage 100ug/mL.Moreover,the Orthosiphon aristatus(Blume) Miq(O.aristatus).showed the highest stimulatory activity at the concentration of 100 μg/mL.Other than that,four plant extracts significantly(P<0.05) rose the phagocytosis activities of leukocytes in dose dependent manner.However,Annona muricata L.and O.aristatus showed the highest stimulated activities at the 100 pg/mL concentration.Conclusions:The results suggest that methanolic extracts of Cirrus aurantifolia.Alpinia gaiangal,O.aristatus and Annona muricata are able to modulate innate immune system and can potentially be recognized as therapeutic agents for modulating immune system.
基金supported by grants from National Natural Science Foundation of China(3157130570)Young Scientist Supporting Project,Program for Changjiang Scholars and Innovative Research Team in University(IRT_15R62)+1 种基金Farm Animals Germplasm Resource Platform,National Transgenic Creature Breeding Grand Project(2016ZX08008-003)Innovation Base Cultivation and Development Project-research on precise genetic modify in sheep(Z171100002217072)
文摘Background: Interferon-γ(IFN-γ) is critical for innate and adaptive immunity against viral and bacterial infections. IFN-γ reportedly affects the phagocytic ability of monocytes and macrophages as well as regulates pituitary function in humans and mice. The present study analyzed the impact of IFN-γ on monocyte and macrophage phagocytosis, production performance, and pituitary function in vivo and in vitro(in dwarf chickens). IFN-γ was injected into dwarf chickens through a vein, and then, the laying rate, average egg weight, and levels of follicle-stimulating hormone(FSH) and IFN-γ were measured in treatment and control groups. For the in vitro experiment, the pituitary tissues were supplemented with IFN-γ, and the m RNA expression levels of follicle-stimulating hormone beta subunit(FSH-β), interferon gamma receptor 1(IFNGR1),and interferon gamma receptor 2(IFNGR2) in the pituitary were assessed.Results: Monocyte and macrophage phagocytosis product(PP) was decreased by IFN-γ treatment in a dose-dependent manner in vitro. In the in vivo experiment, the level of IFN-γ in the treatment group was higher than that in the control group at 7 d(P < 0.05), 14 d(P < 0.01), and 21 d(P < 0.01) post-injection.Compared with the control group, monocyte and macrophage PP was lower in the treatment group after injection(P < 0.01). The laying rate was higher in the treatment group than in the control group at 2 and3 wk post-injection(P < 0.05). There was a significant difference between the treatment and control groups in the levels of FSH at 1, 3, 7, and 14 d post-injection(P < 0.01). In the in vitro experiment, increased m RNA expression levels of FSH-β, IFNGR1, and IFNGR2 were observed in the treatment group after stimulation with100 U/m L IFN-γ for 24 h compared to those in the control group(P < 0.05).Conclusions: IFN-γ inhibited the phagocytosis of monocytes and macrophages; up-regulated the m RNA expression levels of the FSH-β, IFNGR1, and IFNGR2; enhanced the secretion of FSH; and improved the laying rate. IFN-γ might be an important regulator in the trade-off between the immune effect and production performance in dwarf chickens.
基金Supported by the National Natural Science Foundation of China,No.31701179the China Postdoctoral Science Foundation,No.2016M591877。
文摘BACKGROUND Type Ⅰ diabetes(T1D)is characterized by insulin loss caused by inflammatory cells that excessively infiltrate and destroy the pancreas,resulting in dysregulation of tissue homeostasis,mechanobiological properties,and the immune response.The streptozotocin(STZ)-induced mouse model exhibits multiple features of human T1D and enables mechanistic analysis of disease progression.However,the relationship between the mechanochemical signaling regulation of STZ-induced T1D and macrophage migration and phagocytosis is unclear.AIM To study the mechanochemical regulation of STZ-induced macrophage response on pancreatic beta islet cells to gain a clearer understanding of T1D.METHODS We performed experiments using different methods.We stimulated isolated pancreatic beta islet cells with STZ and then tested the macrophage migration and phagocytosis.RESULTS In this study,we discovered that the integrin-associated surface factor CD47 played a critical role in immune defense in the STZ-induced T1D model by preventing pancreatic beta islet inflammation.In comparison with healthy mice,STZ-treated mice showed decreased levels of CD47 on islet cells and reduced interaction of CD47 with signal regulatory proteinα(SIRPα),which negatively regulates macrophage-mediated phagocytosis.This resulted in weakened islet cell immune defense and promoted macrophage migration and phagocytosis of target inflammatory cells.Moreover,lipopolysaccharide-activated human acute monocytic leukemia THP-1 cells also exhibited enhanced phagocytosis in the STZ-treated islets,and the aggressive attack of the inflammatory islets correlated with impaired CD47-SIRPαinteractions.In addition,CD47 overexpression rescued the pre-labeled targeted cells.CONCLUSION This study indicates that CD47 deficiency promotes the migration and phagocytosis of macrophages and provides mechanistic insights into T1D by associating the interactions between membrane structures and inflammatory disease progression.
基金This project was supported by a grant from the NationalNatural Science Foundation of China (No.38970 75 8)
文摘The effect of transforming growth factor β 2 (TGF β 2) on phagocytosis in bovine trabecular meshwork cells in vitro was investigated. After the cultured bovine trabecular meshwork cells were treated with 0 ng/ml, 0.32 ng/ml, 1 ng/ml, 3.2 ng/ml TGF β 2 for 24 h, latex beads were added into the incubation medium, and the numbers of the latex beads in 20 adjacent cells were counted under a microscope 24 h later, after treatment with Wright’s stain. Our results showed that the average numbers of the latex beads in the trabecular meshwork cells treated with TGF β 2 of different concentrations were 53.1±1.7 beads/cell, 56.4±2.9 beads/cell and 77.9±6.5 beads/cell respectinvely, in comparison with 45.5±3.3 beads/cell of the control group. TGF β 2 significantly increased the number of the latex beads phagocytosed by cultured bovine trabecular meshwork cells in a dose dependent manner. TGF β 2 could promote the phagocytosis of bovine trabecular meshwork cells in vitro . It may be involved in the cellularity decrease of the trabecular meshwork in the patients of primary open angle glaucoma through promoting the phagocytosis of trabecular meshwork cells.
基金the Heilongjiang Natural Science Fund Project (C2017035)。
文摘The purpose of this study was to explore the effects of recombinant human intestinal alkaline phosphatase(recIAP) on human neutrophils in vitro, and the migration, phagocytosis, apoptosis in presence and absence of LPS. In this study, freshly extracted human neutrophils were used to establish an inflammatory cell model, and the control group, recIAP group, LPS group and recIAP +LPS group were set up to stimulate the model. The migration of neutrophils was detected by agarose gel drop method. Fluorescent particles and fluorescent probes were added to different treatment groups, and the phagocytic rate of neutrophils and the release of reactive oxygen species(ROS) from neutrophils were detected by flow cytometry. The apoptosis rate of neutrophils was detected by flow cytometry according to Annexin V-FITC apoptosis detection kit. The results showed that regardless of the presence or absence of LPS, recIAP could inhibit the migration of neutrophils, phagocytosis and the release of ROS. In addition, recIAP could weaken the inhibitory effect of LPS on neutrophils apoptosis.
文摘Living systems have to constantly counter micro-or- ganisms which seek parasitic existence by extracting nutrition (amino acids) from the host. Phagocytosis is the ingestion of micro-creatures by certain cells of living systems for counter nutrition (breakdown of the micro-creature into basic components) as part of cellular adaptive immune response. These particular cells are called phagocytes, all of which are different types of white blood cells or their derivatives. Phagocytes are activated by certain components of the micro-creatures which act as an antigen, generating an- tibody secretion by the phagocyte. This paper develops a digital CMOS circuit model of phagocytosis: the immune response biochemical pathway of a pha- gocyte. A micro-sequenced model has been developed where the different stages in phagocytosis are modeled as different states clocked by circadian time intervals. The model converts the bio-chemical immune system digestive pathway into a cascade of CMOS multi-step logical transformations from micro-crea- ture ingestion to the secretion of indigestible residuals. This modeling technique leads to the understanding of cellular immune deficiency diseases of living systems in the form of logical (electrical) faults in a circuit.
文摘Neutrophils are the most important circulating phagocytes. Circulating mono-cytes and precursors of tissue macrophages also have the ability to phagocytize. Pidotimod (ADIMODTM) exerts immunostimulatory and immunoregulatory effects through the stimulation and regulation of cellular immune responses by lymphocytes Canine herpesvirus (CHV) mainly affect puppies between the first and second weeks of age, causing high morbidity in the litter. To date, there is only one commercial vaccine in Europe to prevent disease. In this work, inactivated CHV cultures were inoculated in rabbits, adsorbed and not adsorbed to chitosan nanoparticles. Phagocytosis in the presence or absence of specific antibodies was measured. Response of virus neutralizing antibodies was also evaluated. AdimodTM enhanced the nonspecific and specific phagocytotic response. The association of the virus to the nanoparticles increased the phagocytic ability of blood cells;however, AdimodTM alone had a greater effect on phagocytic activity and generated a stronger immune response that corresponded to the increased phagocytosis (p TM was used.
文摘Introduction: The existence of receptor-mediated endocytosis (RME) means that selectivity and selectivity occurs in capturing macromolecules. Protein kinase C (PKC) which can be expressed by almost all cells are proteins important in signal transduction groove that plays a role in a number of cell activity, e.g. phagocytosis. Aims: The purpose of this study is to determine the expression of RME after modulating the PKC which is characterized by the number of Candida albicans cells attached to the surface of macrophages. Methods: Peritoneal macrophages cultured BALB/c mice are treated with PMA and/or bisindolylmaleimides of providing levels of 5 ng/ml to 100 ng/ml for 10 minutes. Then immediately insert Candida albicans and observe every 30 minutes for 120 minutes. The research design used the same subject. Data collected in the form of number of Candida albicans cells attached to the surface of macrophages are analyzed with ANOVA statistical test (one way) to show the differences between treatments. Results: The test shows statistically significant difference in the number of Candida albicans cells attached to the surface of macrophages after administration of various levels of PMA (p 0.001). The higher level of PMA is given, the more active the PKC is, the more RME are formed, the more Candida albicans cells attached to the surface of macrophages. Another result shows statistically significant difference in the number of Candida albicans cells attached to the surface of macrophages after administration of various levels of bisindolylmaleimides (p 0.001). The higher level of bisindolylmaleimide is given, the less active PKC is, and the less RME are formed, the less Candida albicans cells attached to the surface of macrophages. Conclusion: Research shows that activator PKC (PMA) can increase the expression of RME on macrophages. Another research shows that inhibitor PKC (bisindolylmaleimides) can decrease the expression of RME on macrophages.
基金supported by the National Natural Science Foundation of China(32102827,31972818,31528019)China Postdoctoral Science Foundation(2019M662959)+1 种基金Guangdong Basic and Applied Basic Research Foundation(2019A1515110987)Special fund for promoting economic development(for modern fishery development)of Guangdong Province(grant number 2019A4).
文摘The defense system of teleost fish organized on innate and adaptive immunity protects them against a wide variety of pathogenic microorganisms in the aquatic environment.Phagocytosis is one of the most effective defense strategies against microbial challenge mainly performed by classical‘professional’phagocytes(including monocytes,macrophages and granulocytes).They contain,kill and process the internalized pathogens for antigen presentation by providing antigenic ligands to initiate activation and clonal expansion of T and B cells,which bridge the innate and adaptive immunity.The discovery of phagocytic B cells in teleost fish has broken the paradigm that primary vertebrate B cells are lack of phagocytosis of particulates,as well as led to the investigation of phagocytic activity of mammalian B-1 B cells.The active phagocytic,microbicidal capabilities and antigen presentation in teleost phagocytic B cell have demonstrated to be similar as professional phagocytes,providing a potential impact on development of new vaccination strategies to prevent and control infectious diseases.In this review,we aim to address current progress on the antimicrobial role of phagocytic B cells in teleost fish by comparing it with other professional phagocytes and mammalian B-1 B cells,and provide the application prospect of phagocytic B cells in developing vaccines as well as the prevention of fish diseases.
基金supported by grants from the National Natural Science Foundation of China (32100549 and 31991193)
文摘O-GlcNAcylation is a post-translational modification that serves as a cellular nutrient sensor and participates in multiple physiological and pathological processes.However,it remains uncertain whether O-GlcNAcylation is involved in the regulation of phagocytosis.Here,we demonstrate a rapid increase in protein OGlcNAcylation in response to phagocytotic stimuli.Knockout of the O-GlcNAc transferase or pharmacological inhibition of O-GlcNAcylation dramatically blocks phagocytosis,resulting in the disruption of retinal structure and function.Mechanistic studies reveal that the O-GlcNAc transferase interacts with Ezrin,a membrane-cytoskeleton linker protein,to catalyze its O-GlcNAcylation.Our data further show that Ezrin OGlcNAcylation promotes its localization to the cell cortex,thereby stimulating the membrane-cytoskeleton interaction needed for efficient phagocytosis.These findings identify a previously unrecognized role for protein O-GlcNAcylation in phagocytosis with important implications in both health and diseases.
基金supported by the US National Institutes of Health(NIH)grants R35GM118337,R01HL076179,R01AA028947,U01AI133655 and U01AI170018MA is supported by the US NIH grants R01GM129633 and U01AI170018.
文摘In sepsis, macrophage bacterial phagocytosis is impaired, but the mechanism is not well elucidated. Extracellular cold-inducible RNA-binding protein (eCIRP) is a damage-associated molecular pattern that causes inflammation. However, whether eCIRP regulates macrophage bacterial phagocytosis is unknown. Here, we reported that the bacterial loads in the blood and peritoneal fluid were decreased in CIRP^(−/−) mice and anti-eCIRP Ab-treated mice after sepsis. Increased eCIRP levels were correlated with decreased bacterial clearance in septic mice. CIRP−/− mice showed a marked increase in survival after sepsis. Recombinant murine CIRP (rmCIRP) significantly decreased the phagocytosis of bacteria by macrophages in vivo and in vitro. rmCIRP decreased the protein expression of actin-binding proteins, ARP2, and p-cofilin in macrophages. rmCIRP significantly downregulated the protein expression of βPIX, a Rac1 activator. We further demonstrated that STAT3 and βPIX formed a complex following rmCIRP treatment, preventing βPIX from activating Rac1. We also found that eCIRP-induced STAT3 phosphorylation was required for eCIRP’s action in actin remodeling. Inhibition of STAT3 phosphorylation prevented the formation of the STAT3-βPIX complex, restoring ARP2 and p-cofilin expression and membrane protrusion in rmCIRP-treated macrophages. The STAT3 inhibitor stattic rescued the macrophage phagocytic dysfunction induced by rmCIRP. Thus, we identified a novel mechanism of macrophage phagocytic dysfunction caused by eCIRP, which provides a new therapeutic target to ameliorate sepsis.
基金supported in part by the National Institutes of Health grant 5R01NS117364-02(to JT)。
文摘Germinal matrix hemorrhage is one of the leading causes of morbidity,mortality,and acquired infantile hydrocephalus in preterm infants in the United States,with little progress made in its clinical management.Blood clots have been shown to elicit secondary brain injury after germinal matrix hemorrhage,by disrupting normal cerebrospinal fluid circulation and absorption after germinal matrix hemorrhage causing post-hemorrhagic hydrocephalus development.Current evidence suggests that rapid hematoma resolution is necessary to improve neurological outcomes after hemorrhagic stroke.Various articles have demonstrated the beneficial effects of stimulating the polarization of microglia cells into the M2 phenotype,as it has been suggested that they play an essential role in the rapid phagocytosis of the blood clot after hemorrhagic models of stroke.N-formyl peptide receptor 2(FPR2),a G-protein-coupled receptor,has been shown to be neuroprotective after stroke.FPR2 activation has been associated with the upregulation of phagocytic macrophage clearance,yet its mechanism has not been fully explored.Recent literature suggests that FPR2 may play a role in the stimulation of scavenger receptor CD36.Scavenger receptor CD36 plays a vital role in microglia phagocytic blood clot clearance after germinal matrix hemorrhage.FPR2 has been shown to phosphorylate extracellular-signal-regulated kinase 1/2(ERK1/2),which then promotes the transcription of the dual-specificity protein phosphatase 1(DUSP1)gene.In this review,we present an intrinsic outline of the main components involved in FPR2 stimulation and hematoma resolution after germinal matrix hemorrhage.
基金supported by the National Natural Science Foundation of China,No.81971097(to JY)。
文摘Preclinical and clinical studies have shown that microglia and macrophages participate in a multiphasic brain damage repair process following intracerebral hemorrhage.The E26 transformation-specific sequence-related transcription factor Spi1 regulates microglial/macrophage commitment and maturation.However,the effect of Spi1 on intracerebral hemorrhage remains unclear.In this study,we found that Spi1 may regulate recovery from the neuroinflammation and neurofunctional damage caused by intracerebral hemorrhage by modulating the microglial/macrophage transcriptome.We showed that high Spi1expression in microglia/macrophages after intracerebral hemorrhage is associated with the activation of many pathways that promote phagocytosis,glycolysis,and autophagy,as well as debris clearance and sustained remyelination.Notably,microglia with higher levels of Soil expression were chara cterized by activation of pathways associated with a variety of hemorrhage-related cellular processes,such as complement activation,angiogenesis,and coagulation.In conclusion,our results suggest that Spi1 plays a vital role in the microglial/macrophage inflammatory response following intracerebral hemorrhage.This new insight into the regulation of Spi1 and its target genes may advance our understanding of neuroinflammation in intracerebral hemorrhage and provide therapeutic targets for patients with intracerebral hemorrhage.
基金supported by the National Natural Science Foundation of China (Nos.81973301, 82003732 and 81773701)the Medical Research Project of Jiangsu Commission of Health (No.ZDA2020006, China)+3 种基金the Natural Science Foundation of the Jiangsu Higher Education Institutions of China (No.18KJA310004)the Major Project of Nanjing Medical University (No.NMUD2018008, China)the Postgraduate Research and Practice Innovation Program of Jiangsu Province (Nos.KYCX19_1121 and KYCX20_1417, China)Priority Academic Program Development of Jiangsu Higer Education Institutions (China)
文摘The mechanism of sphingosine-1-phosphate(S1P)-mediated phagocytosis remains unknown.Here,we found that S1P or FTY720(an analog of S1P)promoted microglial phagocytosis in stroke independent of S1PRs.First,we used computer simulation of molecular docking to predict that S1P might be a ligand for triggering receptor expressed on myeloid cells 2(TREM2).Next,microscale thermophoresis(MST),surface plasmon resonance(SPR)and liquid chromatography–tandem mass spectrometry(LC–MS/MS)were performed to reveal that S1P was a novel TREM2 ligand.Then,we confirmed the pro-phagocytosis of S1P targeting in Trem2-Dap12 transfected CHO cells and TREM2 knockdown microglia.Point mutation analysis showed that D104 was the critical binding residue.Trem2^(−/−)mice were used to demonstrate the role of S1P-induced phagocytosis targeting on TREM2 in protecting against ischemic brain injury.Finally,further studies revealed that apolipoprotein E(APOE)loaded with S1P was released by microglia and bound to apoptotic neurons via LDL receptor related protein 1B(LRP1B)and thereby induced microglia to phagocytose apoptotic neurons.Overall,the present work reveals for the first time that S1P acts as a novel endogenous ligand of TREM2 to effectively promote microglial phagocytosis.Our findings provide a new lead compound for developing immunomodulator targeting on TREM2.
