Macrophage Phagocytosis Function Research Articles

A Twindrive Precise Delivery System of Platelet-Neutrophil Hybrid Membrane Regulates Macrophage Combined with CD47 Blocking for Postoperative Immunotherapy.

During wound healing after cancer surgery, platelets, neutrophils, and macrophages accumulate at the wound site and induce important pathophysiological features. Utilizing these pathophysiological features, the development of targeted delivery systems for postoperative tumor immunotherapy is an important strategy. Herein, a twindrive precise delivery system of hybrid membrane combined with CD47 blocking is developed for targeted delivery and targeted regulation to induce postoperative immunotherapy. The precise delivery system consists of IR820-modified platelet-neutrophil hybrid membranes loaded with R848 nanoparticles. Based on the pathological characteristics of platelet aggregation and neutrophil tendency caused by the wound inflammatory microenvironment after tumor surgery, the twindrive delivery system could achieve targeted delivery and targeted regulation of immune drugs to tumor sites. After precise delivery guided by fluorescence imaging, R848 is targeted to reprogram M2 macrophages into M1 macrophages, stimulate dendritic cell maturation as an adjuvant, and then activate T cell immunity. R848 polarization and CD47 blockade together enhanced the phagocytosis function of macrophages, which combined with T cell-mediated cellular immune response to finally effectively inhibit postsurgical tumor recurrence, metastasis, and prolonged survival time. It develops a targeted delivery and regulatory system for cell-specific responses to the pathophysiological features of wound healing for postoperative immunotherapy.

Attenuated Salmonella carrying siRNA-CD24 improved the effect of oxaliplatin on HCC

Oxaliplatin is a chemotherapy drug currently utilized in the treatment of advanced cancer patients. However, its tolerability poses a limitation to its clinical application. Studies have demonstrated that the presence of tumor-associated macrophages is positively correlated with poor prognosis in various solid tumors, including hepatocellular carcinoma (HCC), and is a significant factor contributing to oxaliplatin resistance. Therefore, targeting tumor-associated macrophages may be an effective strategy to improve the efficacy of oxaliplatin in the treatment of HCC patients. CD24 is a novel target for tumor therapy that can interact with the inhibitory receptor Siglec-10 on tumor-associated macrophages, transmitting immune inhibitory signals and inhibiting macrophage phagocytosis function. In this study, we utilized RNAi technology to inhibit the expression of CD24 in tumor cells and combined it with oxaliplatin, resulting in reduced tumor invasion, migration, and proliferation, as well as increased cell apoptosis. Furthermore, immunofluorescence and flow cytometry results indicated that both the single treatment group and combination treatment group enhanced the infiltration of immune cells. This study presents a novel approach to identifying combination therapy and targets for the clinical treatment of HCC with oxaliplatin.

Characterization and in vivo immunomodulatory effects of a heteropolysaccharide from Rhizopogon rubescens (Tul.) Tul

This study is the first to isolate and purify the primary polysaccharide fraction (PPRR) from Rhizopogon rubescens (Tul.) Tul using ultrasonic-assisted hot water extraction. PPRR is a heteropolysaccharide composed of glucose, galactose, fucose, rhamnose, mannose, and xylose. After preliminary structural characterization, the main chain of PPRR is →3)-β-D-Glcp-(1→6)-β-D-Glcp-(1→. In vivo experiments showed that PPRR has significant therapeutic effects on the immune damage caused by cyclophosphamide (CPA). In a concentration range of 1–6 mg/mL, PPRR could augment the macrophage phagocytosis function and regulate the abnormal secretion of cytokines such as interleukin (IL)− 2 and interferon (IFN)-γ. Moreover, PPRR could reduce the inhibition of CPA on hematopoiesis of bone marrow and alleviate the damage caused by CPA to the thymus and spleen. These findings suggest that PPRR has the potential to be used as an immunomodulator in the future.

Effect of alveolar macrophages phagocytosis on prognosis in patients with acute respiratory distress syndrome caused by abdominal infection: a multicenter study

To investigate the effects of alveolar macrophage phagocytosis on prognosis in patients with acute respiratory distress syndrome (ARDS) caused by abdominal infection. ARDS patients caused by severe intra-abdominal infection admitted to intensive care unit (ICU) of Tianjin Fourth Central Hospital, Tianjin Nankai Hospital, Tianjin First Central Hospital and Tianjin Fifth Central Hospital from June 2016 to March 2018 were enrolled. The gender, age, acute physiology and chronic health evaluation II (APACHE II) within 24 hours of admission, neutral red phagocytosis and alkaline phosphatase activity of macrophages in bronchoalveolar lavage fluid, the length of ICU stay, total hospitalization time, hospitalization expenses, and prognosis were recorded. According to the prognosis, the patients were divided into death group and survival group, and the parameters were compared between the two groups. Pearson test was used to analyze the correlation between neutral red phagocytosis function of macrophages and alkaline phosphatase activity and other indicators. The prognosis was analyzed by binary Logistic regression combined with neutral red phagocytosis and alkaline phosphatase activity in patients, and the predictive value of both subjects on prognosis was analyzed by the receiver operating characteristic (ROC) curve. Twenty patients were enrolled in the study, with 8 in the death group and 12 in the survival group. Compared with the survival group, the death group was older (years old: 58.50±14.86 vs. 46.67±13.40), APACHE II score was higher (21.50±3.93 vs. 13.58±4.12), neutral red phagocytosis ability and alkaline phosphatase activity of alveolar macrophages were significantly decreased (A value: 0.265±0.050 vs. 0.338±0.016; μmol/L: 12.06±1.24 vs. 17.96±3.90), and the length of ICU stay was significantly longer (days: 22.00±14.59 vs. 11.50±3.17), hospitalization cost was significantly increased (10 thousand Yuan: 24.17±11.02 vs. 13.44±3.53), the total hospitalization time was shorter (days: 25.25±15.01 vs. 35.67±8.58), and the difference was statistically significant (all P < 0.05). There was no significant difference in gender between the survival group and the death group [male (case): 8 vs. 6, P > 0.05]. The neutral red phagocytosis ability of alveolar macrophages in ARDS patients caused by abdominal infection was negatively correlated with age, APACHE II score and the length of ICU stay (r value was -0.328, -0.572, -0.809, respectively, all P < 0.05); alkaline phosphatase activity was negatively correlated with age, APACHE II score, the length of ICU stay and hospitalization expenses (r value was -0.334, -0.583, -0.470, -0.517, respectively, all P < 0.05). Binary Logistic regression analysis showed that neutral red phagocytosis [odds ratio (OR) = 0.596, 95% confidence interval (95%CI) = 0.212-0.997] and alkaline phosphatase activity (OR = 0.573, 95%CI = 0.339-0.968) were the influencing factors of prognosis (both P < 0.05). ROC curve analysis showed that the AUC of neutral red phagocytosis ability for prognosis of ARDS patients caused by abdominal infection was 0.948, and the sensitivity and specificity were 91.7% and 87.5% when the off-cut value was 0.317. The AUC of alkaline phosphatase for the prognosis of ARDS patients caused by abdominal infection was 0.813; when the cut-off value was 19.72 μmol/L, the sensitivity was 75.0%, and the specificity was 87.5%. The alveolar macrophage phagocytosis dysfunction in ARDS patients caused by severe abdominal infection was not only related to the severity of the disease, but also increased the medical burden of patients, and significantly affected the mortality of such patients.

Structural elucidation and immunostimulatory activity of a new polysaccharide from Cordyceps militaris.

A new polysaccharide (CMPB90-1) was isolated from cultured Cordyceps militaris by alkaline extraction. The chemical structure of CMPB90-1 was determined by analysis of physicochemical and spectral data. The backbone of CMPB90-1 is composed of (1→6)-linked α-d-glucopyranosyl and (1→3)-linked α-d-glucopyranosyl residues, with branching at O-6, which consists of (1→4)-linked β-d-mannopyranosyl and (1→6)-linked α-d-glucopyranosyl residues, respectively. β-d-Galactopyranosyl residues is the terminal unit. In vitro immunomodulatory assay revealed that CMPB90-1 promoted proliferation of splenic lymphocytes, enhanced cytotoxicity of NK cells and promoted lymphocyte secretion of the cytokine interleukin-2. Besides, CMPB90-1 upregulated T-cell subpopulation, strengthened phagocytosis function of macrophages and induced their M1 polarization. The mechanism of the effects might be due to the activation of TLR2, MAPK and NF-κB pathways. The results proposed that CMPB90-1 can be researched and developed as a new functional food.

Phagocytosis Deficiency of Macrophages in NOD.H-2h4 Mice Accelerates the Severity of Iodine-Induced Autoimmune Thyroiditis.

Apoptosis occurs in many autoimmune diseases. Excess iodine induces thyrocyte apoptosis and increases the incidence and prevalence of autoimmune thyroiditis (AIT). However, the sequence of events between the appearance of thyrocyte apoptosis and the occurrence of thyroiditis remains uncharacterized. Furthermore, few studies have investigated the role of macrophage phagocytosis in the development of AIT. Therefore, we evaluated the relationship between apoptosis and inflammatory infiltration in NOD.H-2h4 mouse thyroids by comparing the sequence of events in tissue samples. We also investigated the role of macrophages by comparing macrophage phagocytosis function in BALB/c, C57BL/6, and NOD.H-2h4 mice treated with different levels of iodine. Terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assays and thyroid inflammatory scores revealed that apoptosis (2weeks) occurred before inflammatory infiltration (4weeks). Phosphatidylserine (PS) expression on the extracellular surface of the cell membrane and double-stranded DNA fragments associated with apoptosis appeared at 2 and 8weeks, respectively. Additionally, although apoptosis was enhanced in the thyroids of mice supplemented with excess iodine (0.05±0.12 vs 1.63±0.82% for BALB/c, 0.09±0.14 vs 1.51±0.34% for C57BL/6, and 0.07±1.11 vs 4.72±0.62% for NOD.H-2h4 mice), only NOD.H-2h4 mouse thyroids presented with inflammation. Furthermore, macrophages from NOD.H-2h4 mice (44.46±1.79%) exhibited decreased phagocytotic activity relative to that in BALB/c (54.21±4.58%) and C57BL/6 (58.96±4.04%) mice. There were no differences in phagocytosis function between NOD.H-2h4 mice supplemented with excess iodine or left untreated (24.50±2.66 vs 21.71±1.79%, p=0.06). In conclusion, deficiencies in the apoptosis clearance of macrophages in NOD.H-2h4 mice may constitute an early pathogenic mechanism in AIT that is not influenced by iodine intake.

Impact of high-dose vitamin D3 on plasma free 25-hydroxyvitamin D concentrations and antimicrobial peptides in critically ill mechanically ventilated adults.

High-dose vitamin D3 increases plasma total 25-hydroxyvitamin D [25(OH)D] in critically ill, ventilated patients; however, to our knowledge, the effect on plasma levels of free (nonprotein-bound) 25(OH)D has not been investigated in critical illness. Moreover, the relationship of free 25(OH)D and the regulation of endogenous antimicrobial peptides (AMPs) remains unknown. The aims of this study were to determine in critically ill adults with respiratory failure the effect of previous high-dose regimens of vitamin D3 on free 25(OH)D concentrations, the relationship of free 25(OH)D with circulating cathelicidin (LL-37) and human beta-defensin-2 (hBD-2), and the associations between plasma levels of free 25(OH)D and these AMPs to alveolar macrophage phagocytosis function. In a double blind, randomized controlled trial, critically ill ventilator-dependent adults (N=30) received enteral vitamin D3 (250,000 or 500,000 IU total over 5d) or placebo. Plasma was obtained serially for concentrations of free 25(OH)D, LL-37, hBD-2, and expression of peripheral blood mononuclear cell human cationic antimicrobial protein (hCAP18) mRNA. Total 25(OH)D and LL-37 concentrations and alveolar macrophage phagocytosis were determined in bronchoalveolar lavage fluid. Plasma concentrations of free 25(OH)D over time were correlated with total 25(OH)D levels (r=0.82; P<0.001). The increase in free 25(OH)D was greater with the 500 000 IU vitamin D3 dose than with the lower dose. The percent change in mRNA expression of hCAP18 was positively associated with percent change in free 25(OH)D at days 7 and 14 (ρ=0.48; P=0.04 and ρ=0.59; P=0.03, respectively). Additionally, plasma LL-37 levels correlated with the percentage of alveolar macrophages exhibiting phagocytosis (ρ=0.51; P=0.04). The present study found a dose-related increase in plasma free-25(OH)D levels, which was associated with increasing circulating mRNA expression of hCAP18 over time. There were no correlations between changes in total and free 25(OH)D against plasma LL-37 and hBD-2 concentrations. Larger studies appear warranted to determine the impact of high-dose vitamin D3 administration on endogenous AMPs.

Impact of different temperatures and ambient PM2.5 on the cytotoxicity and cytophagocytic function of alveolar macrophages of rat

To investigate the interactive effects of different temperatures and ambient PM2.5 on the rat alveolar macrophages. The rat alveolar macrophages were collected. The cells were exposed in vitro to 18℃, 24℃, 30℃, 37℃ and 43℃ with PM2.5 at the concentrations of 100 μg/ml, 50 μg/ml, 25 μg/ml and 0 μg/ml respectively. The cells were cultured in the different cases for 8 hours, then cytotoxicity was assessed by 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide(MTT)reduction assay and phagocytosis function of macrophages was assessed by neutral red absorption test. The relative survival rate and the cytophagocytic function of alveolar macrophages of rats among the different concentration groups decreased significantly (P<0.05) compared with the blank control group. Both were dose-dependent. The 37℃ group had the highest level of relative survival rate and the cytophagocytic function compared with other different temperatures groups. Interactive effect of different temperatures and ambient PM2.5 was not observed. But the lower temperature and the higher PM2.5 concentration group had stronger toxicity to alveolar macrophages. The results suggested that different temperatures and ambient PM2.5 have cytotoxicity on alveolar macrophages,injuring the phagocytosis. The two factors had some interaction.

CX3CR1 deficiency delays acute skeletal muscle injury repair by impairing macrophage functions.

Adequate inflammatory response predominated by macrophage infiltration is essential to acute skeletal muscle injury repair. The majority of intramuscular macrophages express the chemokine receptor CX3CR1. We studied the role of CX3CR1 in regulating intramuscular macrophage number and function in acute injury repair by using a loss-of-function approach. Muscle injury repair was delayed in CX3CR1(GFP/GFP) mice as compared with wild-type (WT) controls. CX3CR1 was predominantly expressed by macrophages but not by myogenic cells or capillary endothelia cells in injured muscles. Intramuscular macrophage number and subset composition were not altered by CX3CR1 deficiency. Intramuscular macrophage phagocytosis function was impaired by CX3CR1 deficiency as demonstrated by increased number of necrotic fibers (+115%) and percentage of necrotic area (+204%) at 7 d, increased number of intramuscular neutrophils at 3 (+89%) but not 1 d, reduced number of phagocytosing macrophages (-12%) and phagocytosed beads within macrophages (-15%) in CX3CR1(GFP/GFP) mice as compared with WT controls. The mRNA expression of CD36 (-50%), CD14 (-43%), IGF-1 (-53%), and IL-6 (-40%) was reduced in CX3CR1-deficient macrophages as compared with WT controls. We conclude that CX3CR1 is important to acute skeletal muscle injury repair by regulating macrophage phagocytosis function and trophic growth factor production.

Role of PON2 in innate immune response in an acute infection model

N-(3-oxododecanoyl)-l-homoserine lactone (3OC12-HSL) is a quorum-sensing molecule produced by gram-negative microbial pathogens such as Pseudomonas aeruginosa (PAO1). 3OC12-HSL is involved in the regulation of bacterial virulence factors and also alters the function of the host immune cells. Others and we have previously shown that paraoxonase 2 (PON2), a member of the paraoxonase gene family expressed in immune cells, hydrolyzes 3OC12-HSL. In this study, we examined i) whether macrophage PON2 participates in 3OC12-HSL hydrolysis, ii) the effect of PON2 deficiency in acute PAO1 infection in mice and iii) the effect of 3OC12-HSL on PON2 deficient (PON2-def) macrophages. When compared to wild type macrophages, both intact cells and membrane-enriched protein lysates obtained from PON2-def macrophages show a marked impairment in their ability to hydrolyze 3OC12-HSL. PON2 expression (message and protein) is not altered in response to 3OC12-HSL in macrophages. 3OC12-HSL treated PON2-def macrophages showed i) an increase in ER stress and oxidative stress, ii) defective phosphatidylinositol 3-kinase (PI3 kinase)/AKT activation, and iii) reduced phagocytosis function. Moreover, the nitration to phosphorylation ratio of Tyr458 in p85 protein, the regulatory subunit of PI3-kinase that has been correlated with the phagocytosis function of macrophages, was increased in PON2-def macrophages. Antioxidant treatment reversed the effects of PON2 deficiency in macrophage phagocytosis function. Furthermore, following administration of 1.6×107 CFU of PAO1, bacterial clearance was significantly reduced in the lungs (5.7 fold), liver (2.5 fold), and spleen (14.8 fold) of PON2-def mice when compared to wild type mice. Our results suggest that PON2 plays an important role in innate immune defense against PAO1 infection.

Antitumor and immunomodulatory activity of polysaccharides from the root of Limonium sinense Kuntze

Limonium sinense (Girard) Kuntze is a traditional Chinese folk medicine used for the treatment of fever, hemorrhage, hepatitis and other disorders. The study focused on the antitumor and immunomodulatory activities of L. sinense polysaccharides (LSP) which was obtained from the root of the plant. The antitumor effects of only LSP and LSP in combination with 5-fluorouracil (5-FU) were both evaluated with Heps-bearing tumor mice models. In addition, the macrophage phagocytosis assay, splenocyte proliferation and cytokines production tests were used to assess the immunomodulatory activities of LSP. The results revealed that the LSP (at the dose of 200 and 400mg/kg) had an obvious inhibition on the growth of transplanted mouse tumor. It also exhibited a significant synergistic effect of antitumor activity when combined with 5-FU (p<0.05). Furthermore, the LSP (at the dose of 100 and 200mg/kg) remarkably improved macrophage phagocytosis function in immune suppressed mice. In addition, LSP (at the dose of 50–200μg/ml) showed significant synergistic effects on ConA-stimulated proliferation and IFN-γ and IL-2 production of splenocyte in vitro (p<0.05). These findings suggest that LSP had clear antitumor activity which might be related to its regulation of immune function in mice.

Anti-inflammatory effect of Yijie particles and its mechanism

Objective To investigate the anti-inflammatory effect and mechanism of Yijie particles. Methods Took the energometry of SOD in foot of rats metatarsal inflammatory organization induced by egg white,Maked antibacterial experiment investigation in vitro to observe the anti-inflammatory effect of Yijie particles and observed mice abdominal macrophage phagocytosis function of red blood cells. Results Compared to the control group,the SOD of content in the large,medium and small dose group were statistically significant difference(all P＜0.01),the mice abdominal macrophage phagocytosis percentage of red blood cells and devour exponential increased significantly(all P＜0.01).4 kinds of pathogenic bacteria of the lowest antibacterial and minimum bactericidal concentration(MBC),respectively,streptococcus pneumoniae(MIC 0.286g/ml,MBC 0.429g/ml);Clay white fungus(MIC 0.140g/ml,MBC 0.275g/ml);Pseudomonas aeruginosa(MIC 0.0177g/ml),MBC 0.0358g/ml);E.coli(MIC 0.429g/ml,MBC 0.429g/ml). Conclusion Yijie particles had remarkable anti-inflammatory and better antibacterial effect. Key words: Yijie particles; Anti-inflammatory; SOD; Antibacterial effects

Temporal expression of cyclooxygenase-2 in peritoneal macrophages of rats and effects of panax notoginseng saponins

To explore the temporal expression pattern of cyclooxygenase (COX)-2 and effects of panax notogensing saponins (PNS) in peritoneal macrophages of rats. Phagocytosis function of peritoneal macrophages was measured by chicken red blood cell phagocytosis assay in vitro. Expression of COX-2 mRNA and protein, PGE(2) and PGD(2) production were determined with real-time PCR, Western blotting and radioimmunoassay, respectively. Phagocytosis function of macrophages increased significantly after stimulation and reached peak during 2-3h. Expression of COX-2 mRNA and its protein increased markedly after stimulation and reached the first peak at 2 h and 3h, respectively; and then decreased to reach a minimum at 24h. The second peak appeared at 36h. PNS (50, 100, 200 mg/kg) increased the phagocytosis function obviously at 2h, decreased the expression level of COX-2 and PGE(2) production at 2 h and elevated COX-2 expression and PGD(2) production at 36 h, respectively. COX-2 expression in peritoneal macrophages has a double-hump feature after stimulation. PNS enhanced phagocytosis, inhibiting COX-2 expression at an early stage and elevating it at a later stage.

Antigen sensitization modulates alveolar macrophage functions in an asthma model

We have previously demonstrated that adoptive transfer of alveolar macrophages from allergy-resistant rats to alveolar macrophage-depleted allergic rats prevents airway hyperresponsiveness development, suggesting an important role for alveolar macrophages in asthma pathogenesis. Given that ovalbumin sensitization can modulate alveolar macrophage cytokine production, we investigated the role of sensitized and unsensitized alveolar macrophages in an asthma model. Alveolar macrophages from unsensitized or sensitized Brown Norway rats were transferred to alveolar macrophage-depleted sensitized rats 24 h before allergen challenge. Airway responsiveness to methacholine and airway inflammation were measured the following day. Methacholine concentration needed to increase lung resistance by 200% was significantly higher in alveolar macrophage-depleted sensitized rats that received unsensitized alveolar macrophages compared with alveolar macrophage-depleted sensitized rats that received sensitized alveolar macrophages. Tumor necrosis factor levels in bronchoalveolar lavage fluid of sensitized rats that received unsensitized alveolar macrophages were significantly lower compared with rats that received sensitized alveolar macrophages. Interestingly, alveolar macrophages of unsensitized animals showed higher phagocytosis activity compared with alveolar macrophages of sensitized rats, suggesting that sensitization modulates alveolar macrophage phagocytosis function. Our data suggest an important role of allergen sensitization on alveolar macrophage function in asthma pathogenesis.