Phagocytosis Ability Of Macrophages Research Articles

Structural Characteristics and Immunomodulatory Effects of Melanoidins from Black Garlic.

Melanoidins are considered to have several biological activities. In this study, black garlic melanoidins (MLDs) were collected using ethanol solution extraction; 0%, 20%, and 40% ethanol solutions were used for chromatography. Three kinds of melanoidins were produced by macroporous resin, named MLD-0, MLD-20, and MLD-40. The molecular weight was determined, and the infrared and microscopic structures were studied. In addition, Balb/c mice were induced with cyclophosphamide (CTX) to establish an immune deficiency model to evaluate the immune efficacy of black garlic melanoidins (MLDs). The results showed that MLDs restored the proliferation and phagocytosis ability of macrophages, and the proliferation activity of B lymphocytes in the MD group was 63.32% (♀) and 58.11% (♂) higher than that in the CTX group, respectively. In addition, MLDs alleviated the abnormal expression of serum factors such as IFN-γ, IL-10, and TNF-α. 16SrDNA sequencing of intestinal fecal samples of mice showed that MLDs changed the structure and quantity of intestinal flora, and especially that the relative abundance of Bacteroidaceae was significantly increased. The relative abundance of Staphylococcaceae was significantly reduced. These results showed that MLDs improved the diversity of intestinal flora in mice, and improved the adverse state of immune organs and immune cells. The experiments confirm that black garlic melanoidins have potential value in immune activity, which provides an important basis for the development and utilization of melioidosis.

PH-responsive Astragalus polysaccharide-loaded PLGA nanoparticles as an adjuvant system to improve immune responses

Modern medical science believes that astragalus polysaccharides (APS) have the efficacy of strengthening immune system, while their peculiarities greatly reduced clinical applications. Poly(lactic-co-glycolic acid) (PLGA) is a synthetic carrier material with outstanding biochemical properties. In this study, PLGA materials were used to prepare the novel pH-responsive targeting drug delivery carriers which were encapsulated APS inside. The OVA-loaded pH-responsive APS-encapsulated PLGA Nanoparticles (OVA-loaded pH-responsive APSPs) and the OVA-loaded APSPs were constructed by multiple emulsion solvent evaporation method. Characterization and immunoenhancing activities of PLGA nanoparticles (NPs) were evaluated in vitro and in vivo. The size of NPs ranged from 142.6 to 194.6 nm, and all NPs were negatively charged. Additionally, pH-responsive APSPs shown violent release behaviors in an acidic environment. pH-responsive APSPs had low cytotoxicity, and significantly enhanced expression of MHC-II, CD80, CD86, and phagocytosis ability of macrophages. Both OVA-loaded NPs could stimulate greater Th1-biased immune responses compared with APS alone, and they could significantly promote proliferation, differentiation, and maturity of splenic lymphocytes and dendritic cells in mice respectively. NPs induced significantly greater antigen-specific IgG antibody responses and expression of IL-4, IL-6, IFN-γ, and TNF-α. Moreover, OVA-loaded pH-responsive APSPs had an aptitude for both cellular and humoral immunity reinforcement during early immunization, while OVA-loaded APSPs had advantages on later stages of immune responses.

An evaluation of the effects of Pistacia atlantica gum hydro-alcoholic extract on the phagocytosis ability of macrophages and atherosclerosis development in hypercholesteremic rats.

Atherosclerosis is an inflammatory disease that various factors affect the onset and its progression, including free radicals, hypertension, diabetes, genetic changes, hypercholesterolemia, and even some microorganisms such as herpes viruses and chlamydia. Therefore, compounds that can be effective in any of the above cases may be considered as a useful therapeutic agent in the process of atherosclerosis. The aim of the present study was to evaluate the effects of Pistacia atlantica gum hydro-alcoholic extract on macrophage phagocytosis ability and development of atherosclerosis in hypercholesterolemic rats. The statistical population of the present study consisted of 25 rats that were randomly divided into 5 groups (one control group under standard diet, 4 treatment groups under high-fat diet). After consumption of high-fat food for 45 days, the treatment groups orally received 100, 200, and 400 mg/kg of Pistacia atlantica gum hydro-alcoholic extract for 30 days. Then, peritoneal macrophages were isolated and blood samples were collected to measure the level of nitroblue tetrazolium (NBT), low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), and triglyceride (TG). P ˂ 0.05 was considered significant in all evaluations. The level of cholesterol (503.66 ± 17.15), TG (436.66 ± 16.80), LDL-C (343.66 ± 11.59), HDL-C (54.33 ± 7.02), and NBT (0.64 ± 0.02) decreased in the treatment groups. Besides, exactly in a concentration-dependent manner, plant extract significantly reduced the level of respiratory potential level in macrophages. Hydro-alcoholic extract of Pistacia atlantica gum could effectively decrease hypercholesterolemia and increase phagocytic ability of macrophages. Therefore, it can be suggested for more investigation as a blockage of atherosclerosis.

Transfer of miRNA in tumor-derived exosomes suppresses breast tumor cell invasion and migration by inducing M1 polarization in macrophages

AimsMacrophage repolarization from M1 to M2 phenotype is one of the hallmarks of malignancy. M2 macrophages are the most represented population in the tumor microenvironment and play an active role in tumor progression. In recent years, microRNAs (miRNAs) have been identified as a regulator of macrophage polarization. Main methodsIn this study, miR-130 was delivered to M2 macrophages using tumor-derived exosomes. Then, we evaluated the macrophage polarization status by assessment of specific markers and cytokines for M1 and M2 phenotype. The phagocytosis ability of macrophages was also investigated. Additionally, we performed migration and invasion assays to detect the effect of macrophage reprogramming on breast cancer cells migration and invasion. Key findingsThe findings of the current study indicated that exosomes efficiently delivered miR-130 into macrophages. Delivery of miR-130 into macrophages resulted in upregulation of M1 specific markers and cytokines, including CD86, Irf5, Nos2, TNF-α, and IL-1β and downregulation of M2 specific markers and cytokines, including CD206, Ym1, Arg, TGF-β, and IL-10. The phagocytosis ability of macrophages also enhanced after treatment with miRNA-loaded exosomes. Furthermore, migration and invasion assays demonstrated reduced ability of 4T1 breast cancer cells for migration and invasion after macrophages reprogramming. SignificanceThese observations suggest that repolarization of M2 macrophages to M1 phenotype using miRNA-containing exosomes can be a therapeutic strategy against tumor invasion and metastasis in breast cancer.

Mesenchymal stem cells transfected with sFgl2 inhibit the acute rejection of heart transplantation in mice by regulating macrophage activation

BackgroundMesenchymal stem cells (MSCs) have become a promising candidate for cell-based immune therapy for acute rejection (AR) after heart transplantation due to possessing immunomodulatory properties. In this study, we evaluated the efficacy of soluble fibronectin-like protein 2 (sFgl2) overexpressing mesenchymal stem cells (sFgl2-MSCs) in inhibiting AR of heart transplantation in mice by regulating immune tolerance through inducing M2 phenotype macrophage polarization.Methods and resultsThe sFgl2, a novel immunomodulatory factor secreted by regulatory T cells, was transfected into MSCs to enhance their immunosuppressive functions. After being co-cultured for 72 h, the sFgl2-MSCs inhibited M1 polarization whereas promoted M2 of polarization macrophages through STAT1 and NF-κB pathways in vitro. Besides, the sFgl2-MSCs significantly enhanced the migration and phagocytosis ability of macrophages stimulated with interferon-γ (IFN-γ) and lipopolysaccharide (LPS). Further, the application potential of sFgl2-MSCs in AR treatment was demonstrated by heterotopic cardiac transplantation in mice. The tissue damage and macrophage infiltration were evaluated by H&E and immunohistochemistry staining, and the secretion of inflammatory cytokines was analyzed by ELISA. The results showed that sFgl2-MSCs injected intravenously were able to locate in the graft, promote the M2 polarization of macrophages in vivo, regulate the local and systemic immune response, significantly protect tissues from damaging, and finally prolonged the survival time of mice heart grafts.ConclusionsFgl2-MSCs ameliorate AR of heart transplantation by regulating macrophages, which provides a new idea for the development of anti-AR treatment methods after heart transplantation.

NF-κB/TWIST1 Mediates Migration and Phagocytosis of Macrophages in the Mice Model of Implant-Associated Staphylococcus aureus Osteomyelitis.

Staphylococcus aureus (S. aureus) infection-induced osteomyelitis is a great challenge in clinic treatment. Identification of the essential genes and biological processes that are specifically changed in mononuclear cells at an early stage of S. aureus osteomyelitis is of great clinical significance. Based on transcriptional dataset GSE16129 available publicly, a bioinformatic analysis was performed to identify the differentially expressed genes of osteomyelitis caused by S. aureus infection. ERBB2, TWIST1, and NANOG were screened out as the most valuable osteomyelitis-related genes (OMRGs). A mice model of implant-associated S. aureus osteomyelitis was used to verify the above genes. We found significantly up-regulated expression of TWIST1 in macrophages and accumulation of macrophages around the infected implant. Meanwhile, S. aureus infection increased the expression of TWIST1, MMP9, and MMP13, and stimulated the migration and phagocytosis function of Raw 264.7 cells. Additionally, knock-down of the expression of TWIST1 by siRNA could significantly down-regulate MMP9 and MMP13 and suppress the migration and phagocytosis ability of macrophages in response to S. aureus infection. Furthermore, we found that NF-κB signaling was activated in Raw 264.7 cells by S. aureus and that inhibition of NF-κB signaling by Bay11–7082 blocked the expression of TWIST1, MMP9, and MMP13 as well as cell migration and phagocytosis evoked by S. aureus. Our findings demonstrate that NF-κB/TWIST1 is necessary for migration and phagocytosis of macrophages in response to S. aureus infection. Our study highlights the essential role of NF-κB/TWIST1 in early innate immune response to S. aureus infection in bone.

Anti-inflammatory effect of hispidin on LPS induced macrophage inflammation through MAPK and JAK1/STAT3 signaling pathways

Severe inflammatory reactions caused by macrophage activation can trigger a systemic immune response. In the present study, we observed the anti-inflammatory properties of hispidin on LPS induced RAW264.7 macrophage cells. Our results showed that hispidin treatment significantly reduced the production of cellular NO, IL-6 and reactive oxygen species (ROS) while has not inhibitory effect on TNF-α productions. Excitingly, hispidin treatment retains the phagocytosis ability of macrophages which enabling them to perform the function of removing foreign invaders. Signaling studies showed, hispidin treatment dramatic suppressed the LPS induced mitogen activated protein kinases (MAPK) and JAK/STAT activations. In conclusion, our findings suggest that hispidin may be a new therapeutic target for clinical treatment of macrophages-mediated inflammatory responses.

TRIM59 Protects Mice From Sepsis by Regulating Inflammation and Phagocytosis in Macrophages.

Sepsis is associated with bacterial invasion and inflammation and has a high mortality rate. Previous studies have demonstrated that tripartite motif 59 (TRIM59) was involved in NF-κB signaling and could promote phagocytosis of macrophages, but the role of TRIM59 in sepsis is still unknown. In our study, we found that TRIM59 was downregulated in lipopolysaccharide (LPS)-stimulated bone marrow-derived macrophages (BMDMs). In the cecal ligation and puncture (CLP) sepsis mice model, the mortality of Trim59flox/floxLyz-Cre (Trim59-cKO) mice was higher, the immune cell infiltration and damage of liver and lung were more severe, and bacteria burden was increased. We also found that TRIM59 altered the production of pro-inflammation cytokines, as well as macrophage phagocytosis ability. Further analysis indicated that NF-κB signal pathway and Fcγ receptors might be involved in these regulations. Our study demonstrated for the first time that TRIM59 protects mice from sepsis by regulating inflammation and phagocytosis in macrophages.

CD40-CD154 interactions between macrophages and natural killer cells during sepsis are critical for macrophage activation and are not interferon gamma dependent.

Natural killer (NK) cell interactions with macrophages have been shown to be important during bacterial sepsis in activating macrophages to improve bacterial clearance. The mechanism for this increased activation, however, is unclear. This study determines the relative roles of interferon (IFN)-gamma and CD40/CD154 direct cell interactions on macrophage and NK cell activation in an experimental model of sepsis. Splenic NK cells and peritoneal macrophages were isolated and cultured alone or in coculture, with and without LPS. CD69 expression on NK cells, phagocytosis ability of macrophages, and cell cytokine production was assessed at 24 and 48 h. Coculture of NK cells and macrophages significantly increased activation levels of both cell types, and through experiments culturing NK cells with supernatants from stimulated macrophages and macrophages with supernatants from stimulated NK cells, this activation was determined to be cell-contact-dependent. Similar experiments were conducted using NK cells from IFN-gamma deficient (-/-) mice, as well as anti-IFN-gamma neutralizing antibody. These experiments determined that IFN-gamma is not required for NK or macrophage activation, although it did augment activation levels. Experiments were again repeated using peritoneal macrophages from CD40-/- mice or splenic NK cells from CD154-/- mice. CD40/CD154 interactions were important in the ingestion of bacteria by macrophages, but did not affect NK cell activation at 24 h. There was, however, a protective effect of CD40/CD154 interactions on NK cell activation-induced cell death that occurred at 48 h. CD40/CD154 interactions between macrophages and NK cells are therefore important in macrophage phagocytosis, and are not dependent on IFN-gamma.

Natural Killer Cell Activation Primes Macrophages to Clear Bacterial Infection

Natural killer (NK) cells are major cytokine producers during bacterial sepsis, but their precise role is undefined. This study investigates the effect of NK cell depletion with and without prior activation on macrophage function and bacterial clearance during cecal ligation and puncture. Two different NK cell-depleting antibodies were used: anti-asialo-GM1 (GM1), a nonactivating antibody, and anti-NK1.1 (NK1.1), an NK cell-activating antibody. C57BL/6 mice were NK depleted with either GM1 or NK1.1 by intraperitoneal injection 7 and 3 days before experimentation. Control animals received isotype immunoglobulin G. Depletion was confirmed by flow cytometry. Bacterial levels in peritoneal washout, blood, and liver were determined 4 hours after cecal ligation and puncture. Macrophage activation was measured by phagocytosis ability and by production of nitric oxide and interleukin-6. Depletion with GM1 resulted in significantly higher bacterial levels at 4 hours, whereas depletion with NK1.1 had the opposite effect of significantly decreasing bacterial levels. Macrophage phagocytosis ability was significantly increased in mice depleted with NK1.1 compared with those mice depleted with GM1. We conclude that activation of NK cells improves bacterial clearance by priming macrophages to help clear a subsequent bacterial challenge. Macrophages are less able to clear bacteria when NK cells are depleted without activation. NK cells are therefore important in bacterial clearance through interactions with macrophages.