In Alzheimer’s disease,microglial phagocytosis is engaged in the pathogenesis as it clears abnormal protein accumulations,debris,and apoptotic cells in the early stages of Alzheimer’s disease,but fuels neuroinflamma...In Alzheimer’s disease,microglial phagocytosis is engaged in the pathogenesis as it clears abnormal protein accumulations,debris,and apoptotic cells in the early stages of Alzheimer’s disease,but fuels neuroinflammation and accelerates disease progression in later stages.In vivo parabiosis experiments in aged animals have demonstrated that blood-born factors modulate synaptic plasticity,neurogenesis,and microglial responses.We hypothesize that peripheral factors can modulate microglial function and thereby possibly influence Alzheimer’s disease pathology.The objective of this study is to investigate the effects of Alzheimer’s disease serum on microglial phagocytosis.Here,we use an immortalized human microglial cell line in an in vitro parabiosis assay to investigate the impact of the serum from individuals diagnosed with Alzheimer’s disease(n=30)and age-matched controls(n=30)(PRODEM study)on microglial phagocytosis.Exposure to Alzheimer’s disease serum increased microglial phagocytic uptake of pH-sensitive fluorescent particles and downregulated expression of the lysosomal master regulator transcription factor EB(TFEB)and of ATPase H^(+)transporting lysosomal V1 subunit B2(ATP6V1B2),a component of the vacuolar ATPase.To identify serum components that may relate to changes in phagocytosis,serum samples of the Three-City Study(3C Study)were used.In the 3C Study,blood samples were collected up to 12 years before the onset of cognitive decline or dementia and their serum metabolome is well-defined.Microglia exposed to the serum of future Alzheimer’s disease patients from the 3C Study displayed an increased phagocytic uptake compared with the serum of matched controls,depending on the presence of the apolipoprotein Eε4 allele in the Alzheimer’s disease patients.Furthermore,microglial phagocytosis correlated inversely with serum levels of the omega-3 fatty acid eicosapentaenoic acid.We confirmed this inverse correlation between eicosapentaenoic acid and phagocytosis in the serum samples of the PRODEM cohort.In addition,in vitro testing of eicosapentaenoic acid on microglial phagocytosis showed a concentration-dependent decrease in phagocytic uptake.In conclusion,following incubation with Alzheimer’s disease blood serum,we observed increased microglial phagocytic uptake and the downregulation of TFEB and ATP6V1B2,possibly indicating lysosomal dysfunction.Furthermore,microglial phagocytosis was inversely correlated with serum eicosapentaenoic acid levels,suggesting an important role for dietary eicosapentaenoic acid in microglial function.展开更多
Objective:Neuropathic pain(NP)is one of the most common forms of chronic pain,yet current treatment options are limited in effectiveness.Peripheral nerve injury activates spinal microglia,altering their inflammatory r...Objective:Neuropathic pain(NP)is one of the most common forms of chronic pain,yet current treatment options are limited in effectiveness.Peripheral nerve injury activates spinal microglia,altering their inflammatory response and phagocytic functions,which contributes to the progression of NP.Most current research on NP focuses on microglial inflammation,with relatively little attention to their phagocytic function.Early growth response factor 2(EGR2)has been shown to regulate microglial phagocytosis,but its specific role in NP remains unclear.This study aims to investigate how EGR2 modulates microglial phagocytosis and its involvement in NP,with the goal of identifying potential therapeutic targets.Methods:Adult male Sprague-Dawley(SD)rats were used to establish a chronic constriction injury(CCI)model of the sciatic nerve.Pain behaviors were assessed on days 1,3,7,10,and 14 post-surgery to confirm successful model induction.The temporal and spatial expression of EGR2 in the spinal cord was examined using real-time quantitative PCR(RT-qPCR),Western blotting,and immunofluorescence staining.Adeno-associated virus(AAV)was used to overexpress EGR2 in the spinal cord,and behavioral assessments were performed to evaluate the effects of EGR2 modulation of NP.CCI and lipopolysaccharide(LPS)models were established in animals and microglial cell lines,respectively,and changes in phagocytic activity were measured using RT-qPCR and fluorescent latex bead uptake assays.After confirming the involvement of microglial phagocytosis in NP,AAV was used to overexpress EGR2 in both in vivo and in vitro models,and phagocytic activity was further evaluated.Finally,eukaryotic transcriptome sequencing was conducted to screen differentially expressed mRNAs,followed by Gene Ontology(GO)and Kyoto Encyclopedia of Genes and Genomes(KEGG)pathway analyses to identify potential downstream effectors of EGR2.Results:The CCI model successfully induced NP.Following CCI,EGR2 expression in the spinal cord was upregulated in parallel with NP development.Overexpression of EGR2 via spinal AAV injection enhanced microglial phagocytic activity and increased pain hypersensitivity in rats.Both animal and cellular models showed that CCI or LPS stimulation enhanced microglial phagocytosis,which was further amplified by EGR2 overexpression.Transcriptomic analysis of spinal cord tissues from CCI rats overexpressing EGR2 revealed upregulation of numerous genes associated with microglial phagocytosis and pain regulation.Among them,Lag3 emerged as a potential downstream target of EGR2.Conclusion:EGR2 contributes to the maintenance of NP by enhancing microglial phagocytosis in the spinal dorsal horn.展开更多
Streptococcus suis serotype 2(SS2)is a zoonotic pathogen that can cause acute infection,such as septicemia in pigs and streptococcal toxic shock-like syndrome(STSLS)in humans,indicating that SS2 can evade innate immun...Streptococcus suis serotype 2(SS2)is a zoonotic pathogen that can cause acute infection,such as septicemia in pigs and streptococcal toxic shock-like syndrome(STSLS)in humans,indicating that SS2 can evade innate immunity.Macrophages perform essential antimicrobial functions in the innate immune system by engulfing and killing pathogens.Previously,a dna K mutant strain that showed impaired phagocytosis resistance ability was screened from the transposon mutant library of SS2,but the specific mechanism is unclear.In this study,we further demonstrated that DnaK was required for SS2 to be antiphagocytosed by macrophages and survive in adverse environments.A mouse challenge experiment indicated that DnaK promoted bacteremia and systemic dissemination of SS2,enhancing bacterial pathogenicity.Western blot and immunofluorescence results indicated that DnaK could be secreted by SS2 and was able to enter RAW264.7 macrophages.Then,the endocytic receptor LRP1 regulated by DnaK was identified through RNA sequencing(RNA-Seq).We found that DnaK decreased both the mRNA and protein levels of LRP1.Knockdown of the LRP1β-chain(LRP1β)significantly decreased the phagocytosis rate of the SS2 strain ZY05719,suggesting that LRP1 is a phagocytic receptor of SS2.Furthermore,inhibitor treatment assays revealed that DnaK decreased LRP1 protein levels through the transcription factor PPARγand the ubiquitin-proteasome system.In summary,DnaK contributes to the phagocytosis resistance of SS2 by decreasing LRP1 protein levels in macrophages,providing new insights into the antiphagocytosis mechanisms of SS2 and helping to understand its pathogenesis.展开更多
Triggering receptor expressed on myeloid cells 2(TREM2)-mediated microglial phagocytosis is an energy-intensive process that plays a crucial role in amyloid beta(Aβ)clearance in Alzheimer’s disease(AD).Energy metabo...Triggering receptor expressed on myeloid cells 2(TREM2)-mediated microglial phagocytosis is an energy-intensive process that plays a crucial role in amyloid beta(Aβ)clearance in Alzheimer’s disease(AD).Energy metabolic reprogramming(EMR)in microglia induced by TREM2 presents therapeutic targets for cognitive impairment in AD.Jiawei Xionggui Decoction(JWXG)has demonstrated effectiveness in enhancing energy supply,protecting microglia,and mitigating cognitive impairment in APP/PS1 mice.However,the mechanism by which JWXG enhances Aβphagocytosis through TREM2-mediated EMR in microglia remains unclear.This study investigates how JWXG facilitates microglial phagocytosis and alleviates cognitive deficits in AD through TREM2-mediated EMR.Microglial phagocytosis was evaluated through immunofluorescence staining in vitro and in vivo.The EMR level of microglia was assessed using high-performance liquid chromatography(HPLC)and enzyme-linked immunosorbent assay(ELISA)kits.The TREM2/protein kinase B(Akt)/mammalian target of rapamycin(mTOR)/hypoxia-inducible factor-1α(HIF-1α)signaling pathway was analyzed using Western blotting in BV_(2) cells.TREM2^(−/−)BV_(2) cells were utilized for reverse validation experiments.The Aβburden,neuropathological features,and cognitive ability in APP/PS1 mice were evaluated using ELISA kits,immunohistochemistry(IHC),and the Morris water maze(MWM)test.JWXG enhanced both the phagocytosis of EMR disorder-BV_(2) cells(EMRD-BV_(2))and increased EMR levels.Notably,these effects were significantly reversed in TREM2^(−/−)BV_(2) cells.JWXG elevated TREM2 expression,adenosine triphosphate(ATP)levels,and microglial phagocytosis in APP/PS1 mice.Additionally,JWXG reduced Aβ-burden,neuropathological lesions,and cognitive deficits in APP/PS1 mice.In conclusion,JWXG promoted TREM2-induced EMR and enhanced microglial phagocytosis,thereby reducing Aβdeposition,improving neuropathological lesions,and alleviating cognitive deficits.展开更多
Phagocytosis and subsequent degradation of pathogens by macrophages play a pivotal role in host innate immune responses to microbial infection. Recent studies have shown that Toll-like receptors （TLRs） play an impor...Phagocytosis and subsequent degradation of pathogens by macrophages play a pivotal role in host innate immune responses to microbial infection. Recent studies have shown that Toll-like receptors （TLRs） play an important role in promoting the clearance of bacteria by up-regulating the phagocytic activity of macrophages. However, information regarding the signaling mechanism of TLR-mediated phagocytosis is still limited. Here, we provide evidence that the stimulation of TLR4 with LPS leads to activation of multiple signaling pathways including MAP kinases, phosphatidylinositide 3-kinase （PI3K）, and small GTPases in the murine macrophage-like cell line RAW264.7. Specific inhibition of Cdc42/Rac or p38 MAP kinase, but not PI3K, reduced TLR4-induced phagocytosis of bacteria. Moreover, we have found that either inhibition of actin polymerization by cytochalasin D or the knockdown of actin by RNAi markedly reduced the activation of Cdc42 and Rac by LPS. TLR4-induced activation of Cdc42 and Rac appears to be independent of MyD88. Taken together, our results described a novel actin-Cdc42/Rac pathway through which TLRs can specifically provoke phagocytosis.展开更多
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
Loss of self-tolerance and expansion of auto-reactive lymphocytes are the basis for autoimmunity. Apoptosis and the rapid clearance of apoptotic cells by phagocytes usually occur as coordinated processes that ensure r...Loss of self-tolerance and expansion of auto-reactive lymphocytes are the basis for autoimmunity. Apoptosis and the rapid clearance of apoptotic cells by phagocytes usually occur as coordinated processes that ensure regulated cellularity and stress response with non-pathological outcomes. Defects in clearance of apoptotic ceils would contribute to the generation of self-reactive lymphocytes, which drive autoimmune disorders such as rheumatoid arthritis （RA） and systemic lupus erythematosus （SLE）. The IL-12 family of cytokines （IL-12, IL-23, and IL-27） and IL-10 are produced by phagocytic macrophages and play critical roles in the regulation of antigen-presenting cells （APCs） and effector lymphocytes during an immune response to pathogens. Inappropriate expression of these cytokines and their dysregulated activities have been strongly implicated in the pathogenesis of several autoimmune diseases. The production of pro- and anti-inflammatory cytokines by phagocytic APCs is delicately regulated during the ingestion of apoptotic cells as part of an intrinsic mechanism to prevent inflammatory autoimmune reactions. How apoptotic cell-derived signals regulate cytokine production is poorly understood. A recent study by our group demonstrated that phagocytosis of apoptotic cells by activated macrophages results in strong inhibition of IL-12 p35 gene expression by activating a novel transcription repressor, which we named GC-binding protein （GC-BP）, through tyrosine dephosphorylation. We are also beginning to understand the molecular mechanisms underlying apoptotic cell-triggered production of IL-10 by phagocytes. These studies will help to elucidate some novel immune regulatory mechanisms and explore the regulation of immune responses to autoantigens with potentials to discover new therapeutic targets for the treatment of autoimmune disorders.展开更多
Apoptosis is a widespread phenomenon that occurs in the brain in both physiological and pathological conditions. Dead ceils must be quickly removed to avoid the further toxic effects they exert in the pa- renchyma, a ...Apoptosis is a widespread phenomenon that occurs in the brain in both physiological and pathological conditions. Dead ceils must be quickly removed to avoid the further toxic effects they exert in the pa- renchyma, 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 obser- vation 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 ceils, resulting in accumulation of debris and inflammation. Herein, we advocate that the efficiency of microglial phagocytosis should be routinely tested in neurodegenerative and neuro- logical 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 the effects and mechanisms of action of glycine on phagocytosis and tumor necrosis factor(TNF)-α secretion by Kupffer cells in vitro. METHODS:Kupffer cells were isolated from normal rats by collage...AIM:To investigate the effects and mechanisms of action of glycine on phagocytosis and tumor necrosis factor(TNF)-α secretion by Kupffer cells in vitro. METHODS:Kupffer cells were isolated from normal rats by collagenase digestion and Percoll density gradient differential centrifugation.After culture for 24 h,Kupffer cells were incubated in fresh Dulbecco's Modification of Eagle's Medium containing glycine (G1:1 mmol/L,G2:10 mmol/L,G3:100 mmol/L and G4:300 mmol/L)for 3 h,then used to measure phagocytosis by a bead test,TNF-α secretion after lipopolysaccharide stimulation by radioactive immunoassay,and microfilament and microtubule expression by staining with phalloidin-fluorescein isothiocyanate (FITC)or a monoclonal anti-α tubulin-FITC antibody, respectively,and evaluated under a ultraviolet fluorescence microscope. RESULTS:Glycine decreased the phagocytosis of Kupffer cells at both 30 min and 60 min(P<0.01,P< 0.05).The numbers of beads phagocytosed by Kupffer cells in 30 min were 16.9±4.0(control),9.6±4.1(G1), 12.1±5.7(G2),8.1±3.2(G3)and 7.5±2.0(G4),and were 22.5±7.9(control),20.1±5.8(G1),19.3±4.8 (G2),13.5±4.7(G3)and 9.2±3.1(G4)after 60 min. TNF-α secretion by Kupffer cells in G1(0.19±0.03),G2 (0.16±0.04),G3(0.14±0.03)and G4(0.13±0.05) was significantly less than that in controls(0.26±0.03, P<0.01),and the decrease in secretion was dose-dependent(P<0.05).Microfilaments of Kupffer cells in G2, G3 and G4 groups were arranged in a disorderly manner. The fluorescence densities of microtubules in G1(53.4± 10.5),G2(54.1±14.6),G3(64.9±12.1)and G4(52.1 ±14.2)were all lower than those in the controls(102.2 ±23.7,P<0.01),but the decrease in microtubule fluorescence density was not dose-dependant. CONCLUSION:Glycine can decrease the phagocytosis and secretion by Kupffer cells in vitro,which may be related to the changes in the expression of microfilaments and microtubules induced by Kupffer cells.展开更多
Acute lung injury(ALI)linked to sepsis has a high mortality rate,with limited treatment options available.In recent studies,medical ozone has shown the potential to alleviate inflammation and infection.Here,we aimed t...Acute lung injury(ALI)linked to sepsis has a high mortality rate,with limited treatment options available.In recent studies,medical ozone has shown the potential to alleviate inflammation and infection.Here,we aimed to evaluate therapeutic potential of medical ozone in a mouse model of the sepsis-induced ALI by measuring behavioral assessments,lung function,and blood flow.Protein levels were quantified by Western blotting.In vitro,we performed experiments on bone marrow-derived macrophages(BMDMs)to investigate the effect of adenosine monophosphate(AMP)-activated protein kinase(AMPK)inhibitors and agonists on their phagocytic activity.The results showed that medical ozone significantly improved the survival rate,ameliorated lung injury,and enhanced lung function and limb microcirculation in mice with ALI.Notably,medical ozone inhibited the formation of neutrophil extracellular traps(NETs),a crucial factor in the ALI development.Additionally,medical ozone counteracted the elevated levels of tissue factor,matrix metalloproteinase-9,and interleukin-1β.In the ALI mice,the effects of ozone were abolished,and BMDMs showed an impaired capacity to engulf NETs following the Sr-a1 knockout.Under normal physiological conditions,the administration of an AMPK antagonist showed similar effects on the Sr-a1 knockout,significantly inhibiting the phagocytosis of NETs by BMDMs.In contrast,AMPK agonists enhanced this phagocytic process.In conclusion,medical ozone may alleviate the sepsis-induced lung injury through the AMPK/SR-A1 pathway,thereby enhancing the phagocytosis of NETs by macrophages.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
OBJECTIVE： To investigate the anti-inflammatory effect of pretreatment with quercetin on macro- phages after Candida albicans infection. METHODS： RAW 264.7 macrophages were used as a target cell line. Cell viability...OBJECTIVE： To investigate the anti-inflammatory effect of pretreatment with quercetin on macro- phages after Candida albicans infection. METHODS： RAW 264.7 macrophages were used as a target cell line. Cell viability after treatment with quercetin at different time points was detected by Carboxyfluorescein diacetate, succinimidyl ester. Phagocytic function of macrophages was deter- mined by a fluorometric assay. Cytokine tumor ne- crosis factor a （TNF-a） production was measured by enzyme-linked immunosorbent assay. F-actin cy- toskeleton of L929 cells was stained by Alexa Fluor 488-phalloidin. RESULTS： Pretreatment with quercetin decreasedcell viability only at the highest concentration of 37 μg/mL 2, 24, and 48 h after the treatment. The phagocytic efficiency of macrophages pretreated with quercetin was significantly decreased in a time- and dose-dependent manner. F-actin label- ing showed that the actin cytoskeleton of the cells started to break down 2 h after treatment. More- over, it notably inhibited cytokine TNF-a produc- tion after Candida albicans infection. CONCLUSION： Pretreatment with quercetin in- duced an anti-inflammatory effect against Candida albicans infection in macrophages.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).
Emerging evidence indicates that microglia activation plays an important role in spinal cord injury（SCI） caused by trauma. Studies have found that inhibiting the Rho/Rho-associated protein kinase（ROCK） signaling p...Emerging evidence indicates that microglia activation plays an important role in spinal cord injury（SCI） caused by trauma. Studies have found that inhibiting the Rho/Rho-associated protein kinase（ROCK） signaling pathway can reduce inflammatory cytokine production by microglia. In this study, Western blotting was conducted to detect ROCK2 expression after the SCI; the ROCK Activity Assay kit was used for assay of ROCK pathway activity; microglia morphology was examined using the CD11 b antibody; electron microscopy was used to detect microglia phagocytosis; TUNEL was used to detect tissue cell apoptosis; myelin staining was performed using an antibody against myelin basic protein（MBP）; behavioral outcomes were evaluated according to the methods of Basso, Beattie, and Bresnahan（BBB）. We observed an increase in ROCK activity and microglial activation after SCI. The microglia became larger and rounder and contained myelin-like substances. Furthermore, treatment with fasudil inhibited neuronal cells apoptosis, alleviated demyelination and the formation of cavities, and improved motor recovery. The experimental evidence reveals that the ROCK inhibitor fasudil can regulate microglial activation, promote cell phagocytosis, and improve the SCI microenvironment to promote SCI repair. Thus, fasudil may be useful for the treatment of SCI.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
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 seco...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
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
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
Parkinson’s disease(PD)poses a significant therapeutic challenge,mainly due to the limited ability of drugs to cross the blood-brain barrier(BBB)without undergoing metabolic transformations.Levodopa,a key component o...Parkinson’s disease(PD)poses a significant therapeutic challenge,mainly due to the limited ability of drugs to cross the blood-brain barrier(BBB)without undergoing metabolic transformations.Levodopa,a key component of dopamine replacement therapy,effectively enhances dopaminergic activity.However,it encounters obstacles from peripheral decarboxylase,hindering its passage through the BBB.Furthermore,levodopa metabolism generates reactive oxygen species(ROS),exacerbating neuronal damage.Systemic pulsatile dosing further disrupts natural physiological buffering mechanisms.In this investigation,we devised a ROS-responsive levodopa prodrug system capable of releasing the drug and reducing ROS levels in the central nervous system.The prodrug was incorporated within second near-infrared region(NIR-II)gold nanorods(AuNRs)and utilized angiopep-2(ANG)for targeted delivery across the BBB.The processes of tight junction opening and endocytosis facilitated improved levodopa transport.ROS scavenging helped alleviate neuronal oxidative stress,leading to enhanced behavioral outcomes and reduced oxidative stress levels in a mouse model of PD.Following treatment,the PD mouse model exhibited enhanced flexibility,balance,and spontaneous exploratory activity.This approach successfully alleviated the motor impairments associated with the disease model.Consequently,our strategy,utilizing NIR-II AuNRs and ANG-mediated BBB penetration,coupled with the responsive release of levodopa,offers a promising approach for dopamine supplementation and microenvironmental regulation.This system holds substantial potential as an efficient platform for delivering neuroprotective drugs and advancing PD therapy.展开更多
基金part of the EU consortium DCog Plast ‘Diet Cognition and Plasticity” funded by the Joint Programming Initiative “A Health Diet for a Healthy Life”(JPI-HDHL) via the BMWFW (BMWFW-10.420/0009-WF/V/3c/2015 and the Medical Research Council UK:MR/N030087/1)(to LA and ST)supported by the PMU-FFF Research Fund (A-16/01/019-AIG)+9 种基金BA by the PMU-Research and Innovation Fund (PMU-RIF)(project 2023-PRE-008-Altendorfer)supported by the Center for Urban Mental Healthby Alzheimer Nederlandthe Zon MW Program Mechanisms Of DEMentia (MODEM)by the Gravitation program iCNS of the Dutch Research Council (NWO)supported by Grant PID2020-114921RB-C21Maria de Maeztu Unit of Excellence grant CEX2021-001234-M funded by MCIU/AEI/and CIBERFESCB16/10/00269, from the Instituto de Salud Carlos III all of them by “ERDF A way of making Europe”the Generalitat de Catalunya’s Agency AGAUR of 2021SGR00687ICREA Award
文摘In Alzheimer’s disease,microglial phagocytosis is engaged in the pathogenesis as it clears abnormal protein accumulations,debris,and apoptotic cells in the early stages of Alzheimer’s disease,but fuels neuroinflammation and accelerates disease progression in later stages.In vivo parabiosis experiments in aged animals have demonstrated that blood-born factors modulate synaptic plasticity,neurogenesis,and microglial responses.We hypothesize that peripheral factors can modulate microglial function and thereby possibly influence Alzheimer’s disease pathology.The objective of this study is to investigate the effects of Alzheimer’s disease serum on microglial phagocytosis.Here,we use an immortalized human microglial cell line in an in vitro parabiosis assay to investigate the impact of the serum from individuals diagnosed with Alzheimer’s disease(n=30)and age-matched controls(n=30)(PRODEM study)on microglial phagocytosis.Exposure to Alzheimer’s disease serum increased microglial phagocytic uptake of pH-sensitive fluorescent particles and downregulated expression of the lysosomal master regulator transcription factor EB(TFEB)and of ATPase H^(+)transporting lysosomal V1 subunit B2(ATP6V1B2),a component of the vacuolar ATPase.To identify serum components that may relate to changes in phagocytosis,serum samples of the Three-City Study(3C Study)were used.In the 3C Study,blood samples were collected up to 12 years before the onset of cognitive decline or dementia and their serum metabolome is well-defined.Microglia exposed to the serum of future Alzheimer’s disease patients from the 3C Study displayed an increased phagocytic uptake compared with the serum of matched controls,depending on the presence of the apolipoprotein Eε4 allele in the Alzheimer’s disease patients.Furthermore,microglial phagocytosis correlated inversely with serum levels of the omega-3 fatty acid eicosapentaenoic acid.We confirmed this inverse correlation between eicosapentaenoic acid and phagocytosis in the serum samples of the PRODEM cohort.In addition,in vitro testing of eicosapentaenoic acid on microglial phagocytosis showed a concentration-dependent decrease in phagocytic uptake.In conclusion,following incubation with Alzheimer’s disease blood serum,we observed increased microglial phagocytic uptake and the downregulation of TFEB and ATP6V1B2,possibly indicating lysosomal dysfunction.Furthermore,microglial phagocytosis was inversely correlated with serum eicosapentaenoic acid levels,suggesting an important role for dietary eicosapentaenoic acid in microglial function.
基金supported by the National Natural Science Foundation of China(82071249 and 81771207).
文摘Objective:Neuropathic pain(NP)is one of the most common forms of chronic pain,yet current treatment options are limited in effectiveness.Peripheral nerve injury activates spinal microglia,altering their inflammatory response and phagocytic functions,which contributes to the progression of NP.Most current research on NP focuses on microglial inflammation,with relatively little attention to their phagocytic function.Early growth response factor 2(EGR2)has been shown to regulate microglial phagocytosis,but its specific role in NP remains unclear.This study aims to investigate how EGR2 modulates microglial phagocytosis and its involvement in NP,with the goal of identifying potential therapeutic targets.Methods:Adult male Sprague-Dawley(SD)rats were used to establish a chronic constriction injury(CCI)model of the sciatic nerve.Pain behaviors were assessed on days 1,3,7,10,and 14 post-surgery to confirm successful model induction.The temporal and spatial expression of EGR2 in the spinal cord was examined using real-time quantitative PCR(RT-qPCR),Western blotting,and immunofluorescence staining.Adeno-associated virus(AAV)was used to overexpress EGR2 in the spinal cord,and behavioral assessments were performed to evaluate the effects of EGR2 modulation of NP.CCI and lipopolysaccharide(LPS)models were established in animals and microglial cell lines,respectively,and changes in phagocytic activity were measured using RT-qPCR and fluorescent latex bead uptake assays.After confirming the involvement of microglial phagocytosis in NP,AAV was used to overexpress EGR2 in both in vivo and in vitro models,and phagocytic activity was further evaluated.Finally,eukaryotic transcriptome sequencing was conducted to screen differentially expressed mRNAs,followed by Gene Ontology(GO)and Kyoto Encyclopedia of Genes and Genomes(KEGG)pathway analyses to identify potential downstream effectors of EGR2.Results:The CCI model successfully induced NP.Following CCI,EGR2 expression in the spinal cord was upregulated in parallel with NP development.Overexpression of EGR2 via spinal AAV injection enhanced microglial phagocytic activity and increased pain hypersensitivity in rats.Both animal and cellular models showed that CCI or LPS stimulation enhanced microglial phagocytosis,which was further amplified by EGR2 overexpression.Transcriptomic analysis of spinal cord tissues from CCI rats overexpressing EGR2 revealed upregulation of numerous genes associated with microglial phagocytosis and pain regulation.Among them,Lag3 emerged as a potential downstream target of EGR2.Conclusion:EGR2 contributes to the maintenance of NP by enhancing microglial phagocytosis in the spinal dorsal horn.
基金funded by the National Key Research and Development Program of China(2021YFD1800400)the National Natural Science Foundation of China(32373018)+2 种基金Jiangsu Agriculture Science and Technology Innovation Fund,China(CX(23)1029)the Excellent Research Innovation Team in Universities in Anhui Province,China(2022AH010088)the Shennong Scholar Project of Anhui Agricultural University,China(rc392101)。
文摘Streptococcus suis serotype 2(SS2)is a zoonotic pathogen that can cause acute infection,such as septicemia in pigs and streptococcal toxic shock-like syndrome(STSLS)in humans,indicating that SS2 can evade innate immunity.Macrophages perform essential antimicrobial functions in the innate immune system by engulfing and killing pathogens.Previously,a dna K mutant strain that showed impaired phagocytosis resistance ability was screened from the transposon mutant library of SS2,but the specific mechanism is unclear.In this study,we further demonstrated that DnaK was required for SS2 to be antiphagocytosed by macrophages and survive in adverse environments.A mouse challenge experiment indicated that DnaK promoted bacteremia and systemic dissemination of SS2,enhancing bacterial pathogenicity.Western blot and immunofluorescence results indicated that DnaK could be secreted by SS2 and was able to enter RAW264.7 macrophages.Then,the endocytic receptor LRP1 regulated by DnaK was identified through RNA sequencing(RNA-Seq).We found that DnaK decreased both the mRNA and protein levels of LRP1.Knockdown of the LRP1β-chain(LRP1β)significantly decreased the phagocytosis rate of the SS2 strain ZY05719,suggesting that LRP1 is a phagocytic receptor of SS2.Furthermore,inhibitor treatment assays revealed that DnaK decreased LRP1 protein levels through the transcription factor PPARγand the ubiquitin-proteasome system.In summary,DnaK contributes to the phagocytosis resistance of SS2 by decreasing LRP1 protein levels in macrophages,providing new insights into the antiphagocytosis mechanisms of SS2 and helping to understand its pathogenesis.
基金supported by the National Natural Science Foundation of China(Nos.82074150 and 82274240)the Natural Science Foundation of Sichuan Province(No.2023NSFSC1779).
文摘Triggering receptor expressed on myeloid cells 2(TREM2)-mediated microglial phagocytosis is an energy-intensive process that plays a crucial role in amyloid beta(Aβ)clearance in Alzheimer’s disease(AD).Energy metabolic reprogramming(EMR)in microglia induced by TREM2 presents therapeutic targets for cognitive impairment in AD.Jiawei Xionggui Decoction(JWXG)has demonstrated effectiveness in enhancing energy supply,protecting microglia,and mitigating cognitive impairment in APP/PS1 mice.However,the mechanism by which JWXG enhances Aβphagocytosis through TREM2-mediated EMR in microglia remains unclear.This study investigates how JWXG facilitates microglial phagocytosis and alleviates cognitive deficits in AD through TREM2-mediated EMR.Microglial phagocytosis was evaluated through immunofluorescence staining in vitro and in vivo.The EMR level of microglia was assessed using high-performance liquid chromatography(HPLC)and enzyme-linked immunosorbent assay(ELISA)kits.The TREM2/protein kinase B(Akt)/mammalian target of rapamycin(mTOR)/hypoxia-inducible factor-1α(HIF-1α)signaling pathway was analyzed using Western blotting in BV_(2) cells.TREM2^(−/−)BV_(2) cells were utilized for reverse validation experiments.The Aβburden,neuropathological features,and cognitive ability in APP/PS1 mice were evaluated using ELISA kits,immunohistochemistry(IHC),and the Morris water maze(MWM)test.JWXG enhanced both the phagocytosis of EMR disorder-BV_(2) cells(EMRD-BV_(2))and increased EMR levels.Notably,these effects were significantly reversed in TREM2^(−/−)BV_(2) cells.JWXG elevated TREM2 expression,adenosine triphosphate(ATP)levels,and microglial phagocytosis in APP/PS1 mice.Additionally,JWXG reduced Aβ-burden,neuropathological lesions,and cognitive deficits in APP/PS1 mice.In conclusion,JWXG promoted TREM2-induced EMR and enhanced microglial phagocytosis,thereby reducing Aβdeposition,improving neuropathological lesions,and alleviating cognitive deficits.
基金Acknowledgments This work is supported by the National Natural Science Foundation of China （project 30321002 and 30471580）, Shanghai E-research Institutes, and Science and Technology Commission of Shanghai Municipality （project 04DZ14902）.
文摘Phagocytosis and subsequent degradation of pathogens by macrophages play a pivotal role in host innate immune responses to microbial infection. Recent studies have shown that Toll-like receptors （TLRs） play an important role in promoting the clearance of bacteria by up-regulating the phagocytic activity of macrophages. However, information regarding the signaling mechanism of TLR-mediated phagocytosis is still limited. Here, we provide evidence that the stimulation of TLR4 with LPS leads to activation of multiple signaling pathways including MAP kinases, phosphatidylinositide 3-kinase （PI3K）, and small GTPases in the murine macrophage-like cell line RAW264.7. Specific inhibition of Cdc42/Rac or p38 MAP kinase, but not PI3K, reduced TLR4-induced phagocytosis of bacteria. Moreover, we have found that either inhibition of actin polymerization by cytochalasin D or the knockdown of actin by RNAi markedly reduced the activation of Cdc42 and Rac by LPS. TLR4-induced activation of Cdc42 and Rac appears to be independent of MyD88. Taken together, our results described a novel actin-Cdc42/Rac pathway through which TLRs can specifically provoke phagocytosis.
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.
文摘Loss of self-tolerance and expansion of auto-reactive lymphocytes are the basis for autoimmunity. Apoptosis and the rapid clearance of apoptotic cells by phagocytes usually occur as coordinated processes that ensure regulated cellularity and stress response with non-pathological outcomes. Defects in clearance of apoptotic ceils would contribute to the generation of self-reactive lymphocytes, which drive autoimmune disorders such as rheumatoid arthritis （RA） and systemic lupus erythematosus （SLE）. The IL-12 family of cytokines （IL-12, IL-23, and IL-27） and IL-10 are produced by phagocytic macrophages and play critical roles in the regulation of antigen-presenting cells （APCs） and effector lymphocytes during an immune response to pathogens. Inappropriate expression of these cytokines and their dysregulated activities have been strongly implicated in the pathogenesis of several autoimmune diseases. The production of pro- and anti-inflammatory cytokines by phagocytic APCs is delicately regulated during the ingestion of apoptotic cells as part of an intrinsic mechanism to prevent inflammatory autoimmune reactions. How apoptotic cell-derived signals regulate cytokine production is poorly understood. A recent study by our group demonstrated that phagocytosis of apoptotic cells by activated macrophages results in strong inhibition of IL-12 p35 gene expression by activating a novel transcription repressor, which we named GC-binding protein （GC-BP）, through tyrosine dephosphorylation. We are also beginning to understand the molecular mechanisms underlying apoptotic cell-triggered production of IL-10 by phagocytes. These studies will help to elucidate some novel immune regulatory mechanisms and explore the regulation of immune responses to autoantigens with potentials to discover new therapeutic targets for the treatment of autoimmune disorders.
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 ceils must be quickly removed to avoid the further toxic effects they exert in the pa- renchyma, 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 obser- vation 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 ceils, resulting in accumulation of debris and inflammation. Herein, we advocate that the efficiency of microglial phagocytosis should be routinely tested in neurodegenerative and neuro- logical 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.
基金Supported by The Natural Science Foundation of Taiyuan City,China, No. 09121014
文摘AIM:To investigate the effects and mechanisms of action of glycine on phagocytosis and tumor necrosis factor(TNF)-α secretion by Kupffer cells in vitro. METHODS:Kupffer cells were isolated from normal rats by collagenase digestion and Percoll density gradient differential centrifugation.After culture for 24 h,Kupffer cells were incubated in fresh Dulbecco's Modification of Eagle's Medium containing glycine (G1:1 mmol/L,G2:10 mmol/L,G3:100 mmol/L and G4:300 mmol/L)for 3 h,then used to measure phagocytosis by a bead test,TNF-α secretion after lipopolysaccharide stimulation by radioactive immunoassay,and microfilament and microtubule expression by staining with phalloidin-fluorescein isothiocyanate (FITC)or a monoclonal anti-α tubulin-FITC antibody, respectively,and evaluated under a ultraviolet fluorescence microscope. RESULTS:Glycine decreased the phagocytosis of Kupffer cells at both 30 min and 60 min(P<0.01,P< 0.05).The numbers of beads phagocytosed by Kupffer cells in 30 min were 16.9±4.0(control),9.6±4.1(G1), 12.1±5.7(G2),8.1±3.2(G3)and 7.5±2.0(G4),and were 22.5±7.9(control),20.1±5.8(G1),19.3±4.8 (G2),13.5±4.7(G3)and 9.2±3.1(G4)after 60 min. TNF-α secretion by Kupffer cells in G1(0.19±0.03),G2 (0.16±0.04),G3(0.14±0.03)and G4(0.13±0.05) was significantly less than that in controls(0.26±0.03, P<0.01),and the decrease in secretion was dose-dependent(P<0.05).Microfilaments of Kupffer cells in G2, G3 and G4 groups were arranged in a disorderly manner. The fluorescence densities of microtubules in G1(53.4± 10.5),G2(54.1±14.6),G3(64.9±12.1)and G4(52.1 ±14.2)were all lower than those in the controls(102.2 ±23.7,P<0.01),but the decrease in microtubule fluorescence density was not dose-dependant. CONCLUSION:Glycine can decrease the phagocytosis and secretion by Kupffer cells in vitro,which may be related to the changes in the expression of microfilaments and microtubules induced by Kupffer cells.
基金supported by the National Natural Science Foundation of China(Grant Nos.82271252,82204542,and 81971047)the Lianyungang Science and Technology Program Project(Grant Nos.SF2122 and SF2214)+2 种基金the Scientific Research Project of Jiangsu Provincial Health Commission(Grant No.Z2021066)the Natural Science Foundation of the Jiangsu Higher Education Institutions of China(Grant No.21KJB310019)the Open Project of Jiangsu Province Key Laboratory of Anesthesiology,Xuzhou Medical University(Grant No.XZSYSKF2021014).
文摘Acute lung injury(ALI)linked to sepsis has a high mortality rate,with limited treatment options available.In recent studies,medical ozone has shown the potential to alleviate inflammation and infection.Here,we aimed to evaluate therapeutic potential of medical ozone in a mouse model of the sepsis-induced ALI by measuring behavioral assessments,lung function,and blood flow.Protein levels were quantified by Western blotting.In vitro,we performed experiments on bone marrow-derived macrophages(BMDMs)to investigate the effect of adenosine monophosphate(AMP)-activated protein kinase(AMPK)inhibitors and agonists on their phagocytic activity.The results showed that medical ozone significantly improved the survival rate,ameliorated lung injury,and enhanced lung function and limb microcirculation in mice with ALI.Notably,medical ozone inhibited the formation of neutrophil extracellular traps(NETs),a crucial factor in the ALI development.Additionally,medical ozone counteracted the elevated levels of tissue factor,matrix metalloproteinase-9,and interleukin-1β.In the ALI mice,the effects of ozone were abolished,and BMDMs showed an impaired capacity to engulf NETs following the Sr-a1 knockout.Under normal physiological conditions,the administration of an AMPK antagonist showed similar effects on the Sr-a1 knockout,significantly inhibiting the phagocytosis of NETs by BMDMs.In contrast,AMPK agonists enhanced this phagocytic process.In conclusion,medical ozone may alleviate the sepsis-induced lung injury through the AMPK/SR-A1 pathway,thereby enhancing the phagocytosis of NETs by macrophages.
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 Grants from Scientific Research Foundation of the Higher Education Institutions of Jiangsu Province,China(No.13KJB310022)Administration of Traditional Chinese Medicine of Jiangsu Province(No.LZ13248)China Postdoctoral Science Foundation(No.2013M541741)
文摘OBJECTIVE： To investigate the anti-inflammatory effect of pretreatment with quercetin on macro- phages after Candida albicans infection. METHODS： RAW 264.7 macrophages were used as a target cell line. Cell viability after treatment with quercetin at different time points was detected by Carboxyfluorescein diacetate, succinimidyl ester. Phagocytic function of macrophages was deter- mined by a fluorometric assay. Cytokine tumor ne- crosis factor a （TNF-a） production was measured by enzyme-linked immunosorbent assay. F-actin cy- toskeleton of L929 cells was stained by Alexa Fluor 488-phalloidin. RESULTS： Pretreatment with quercetin decreasedcell viability only at the highest concentration of 37 μg/mL 2, 24, and 48 h after the treatment. The phagocytic efficiency of macrophages pretreated with quercetin was significantly decreased in a time- and dose-dependent manner. F-actin label- ing showed that the actin cytoskeleton of the cells started to break down 2 h after treatment. More- over, it notably inhibited cytokine TNF-a produc- tion after Candida albicans infection. CONCLUSION： Pretreatment with quercetin in- duced an anti-inflammatory effect against Candida albicans infection in macrophages.
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).
基金supported by grants from Natural Science Foundation of China(No.81471200 and No.81000521)National Basic Research Program of China(No.2011CB504403)the Young Medical Scientists Project of Wuhan(No.2013-12)
文摘Emerging evidence indicates that microglia activation plays an important role in spinal cord injury（SCI） caused by trauma. Studies have found that inhibiting the Rho/Rho-associated protein kinase（ROCK） signaling pathway can reduce inflammatory cytokine production by microglia. In this study, Western blotting was conducted to detect ROCK2 expression after the SCI; the ROCK Activity Assay kit was used for assay of ROCK pathway activity; microglia morphology was examined using the CD11 b antibody; electron microscopy was used to detect microglia phagocytosis; TUNEL was used to detect tissue cell apoptosis; myelin staining was performed using an antibody against myelin basic protein（MBP）; behavioral outcomes were evaluated according to the methods of Basso, Beattie, and Bresnahan（BBB）. We observed an increase in ROCK activity and microglial activation after SCI. The microglia became larger and rounder and contained myelin-like substances. Furthermore, treatment with fasudil inhibited neuronal cells apoptosis, alleviated demyelination and the formation of cavities, and improved motor recovery. The experimental evidence reveals that the ROCK inhibitor fasudil can regulate microglial activation, promote cell phagocytosis, and improve the SCI microenvironment to promote SCI repair. Thus, fasudil may be useful for the treatment of SCI.
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 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.
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.
文摘Parkinson’s disease(PD)poses a significant therapeutic challenge,mainly due to the limited ability of drugs to cross the blood-brain barrier(BBB)without undergoing metabolic transformations.Levodopa,a key component of dopamine replacement therapy,effectively enhances dopaminergic activity.However,it encounters obstacles from peripheral decarboxylase,hindering its passage through the BBB.Furthermore,levodopa metabolism generates reactive oxygen species(ROS),exacerbating neuronal damage.Systemic pulsatile dosing further disrupts natural physiological buffering mechanisms.In this investigation,we devised a ROS-responsive levodopa prodrug system capable of releasing the drug and reducing ROS levels in the central nervous system.The prodrug was incorporated within second near-infrared region(NIR-II)gold nanorods(AuNRs)and utilized angiopep-2(ANG)for targeted delivery across the BBB.The processes of tight junction opening and endocytosis facilitated improved levodopa transport.ROS scavenging helped alleviate neuronal oxidative stress,leading to enhanced behavioral outcomes and reduced oxidative stress levels in a mouse model of PD.Following treatment,the PD mouse model exhibited enhanced flexibility,balance,and spontaneous exploratory activity.This approach successfully alleviated the motor impairments associated with the disease model.Consequently,our strategy,utilizing NIR-II AuNRs and ANG-mediated BBB penetration,coupled with the responsive release of levodopa,offers a promising approach for dopamine supplementation and microenvironmental regulation.This system holds substantial potential as an efficient platform for delivering neuroprotective drugs and advancing PD therapy.
