Phagocytic Activity Of Macrophages Research Articles

Hypotensive drugs mitigate the high-sodium diet-induced pro-inflammatory activation of mouse macrophages in vivo

Nowadays, there is an increasing emphasis on the need to alleviate the chronic inflammatory response to effectively treat hypertension. However, there are still gaps in our understanding on how to achieve this. Therefore, research on interaction of antihypertensive drugs with the immune system is extremely interesting, since their therapeutic effect could partly result from amelioration of hypertension-related inflammation, in which macrophages seem to play a pivotal role. Thus, current comprehensive studies have investigated the impact of repeatedly administered hypotensive drugs (captopril, olmesartan, propranolol, carvedilol, amlodipine, verapamil) on macrophage functions in the innate and adaptive immunity, as well as if drug-induced effects are affected by a high-sodium diet (HSD), one of the key environmental risk factors of hypertension. Although the assayed medications increased the generation of reactive oxygen and nitrogen intermediates by macrophages from standard fed donors, they reversed HSD-induced enhancing effects on macrophage oxidative burst and secretion of pro-inflammatory cytokines. On the other hand, some drugs increased macrophage phagocytic activity and the expression of surface markers involved in antigen presentation, which translated into enhanced macrophage ability to activate B cells for antibody production. Moreover, the assayed medications augmented macrophage function and the effector phase of contact hypersensitivity reaction, but suppressed the sensitization phase of cell-mediated hypersensitivity under HSD conditions. Our current findings contribute to the recognition of mechanisms, by which excessive sodium intake affects macrophage immune activity in hypertensive individuals, and provide evidence that the assayed medications mitigate most of the HSD-induced adverse effects, suggesting their additional protective therapeutic activity.

Unraveling the immune functions of large yellow croaker Tmem208 in response to Pseudomonas plecoglossicida: Insights from cloning, expression profiling, and transcriptome analysis

Pseudomonas plecoglossicida, the causative agent of Visceral White Spot Disease, poses substantial risks to large yellow croaker (Larimichthys crocea) aquaculture. Previous genome-wide association studies (GWAS), directed towards elucidating the resistance mechanisms of large yellow croaker against this affliction, suggested that the transmembrane protein 208 (named Lctmem208) may confer a potential advantage. TMEM proteins, particularly TMEM208 located in the endoplasmic reticulum, plays significant roles in autophagy, ER stress, and dynamics of cancer cell. However, research on TMEM's function in teleost fish immunity remains sparse, highlighting a need for further study. This study embarks on a comprehensive examination of LcTmem208, encompassing cloning, molecular characterization, and its dynamics in immune function in response to Pseudomonas plecoglossicida infection. Our findings reveal that LcTmem208 is highly conserved across teleost species, exhibiting pronounced expression in immune-relevant tissues, which escalates significantly upon pathogenic challenge. Transcriptome analysis subsequent to LcTmem208 overexpression in kidney cells unveiled its pivotal role in modulating immune-responsive processes, notably the p53 signaling pathway and cytokine-mediated interactions. Enhanced phagocytic activity in macrophages overexpressing LcTmem208 underscores its importance in innate immunity. Taken together, this is the first time reported the critical involvement of LcTmem208 in regulating innate immune responses of defensing P. plecoglossicida, thereby offering valuable insights into teleost fish immunity and potential strategies for the selective breeding of disease-resistant strains of large yellow croaker in aquaculture practices.

Empowering macrophages: the cancer fighters within the tumour microenvironment in mantle cell lymphoma.

In Mantle Cell Lymphoma (MCL), the role of macrophages within the tumour microenvironment (TME) has recently gained attention due to their impact on prognosis and response to therapy. Despite their low absolute number in MCL tumour tissue, recent findings reveal an association between the levels of macrophages and prognosis, consistent with trends observed in other lymphoma subtypes. M2-like macrophages, identified by markers such as CD163, contribute to angiogenesis and suppression of the immune response. Clinical trials with MCL patients treated with chemoimmunotherapy and targeted treatments underscore the adverse impact of high levels of M2-like macrophages. Immunomodulatory drugs like lenalidomide reduce the levels of MCL-associated CD163+ macrophages and enhance macrophage phagocytic activity. Similarly, clinical approaches targeting the CD47 "don't eat me" signalling, in combination with the anti-CD20-antibody rituximab, demonstrate increased macrophage activity and phagocytosis of MCL tumour cells. Cell-based therapies such as chimeric antigen receptor (CAR) T-cell have shown promise but various challenges persist, leading to a potential interest in CAR-macrophages (CAR-M). When macrophages are recruited to the TME, they offer advantages including phagocytic function and responsiveness to microenvironment alterations, suggesting their potential as a manipulable and inducible alternative when CAR T-cell therapies fails in the complex landscape of MCL treatment.

DEFB114 protein enhances host resistance to fungal infection through the NOD1/2-ATG16L1-NF-κB signaling pathway

The overuse of antibiotics has led to the enhanced resistance of many pathogenic bacteria, posing a threat to human health. Therefore, there is a need to develop green and safe alternatives to antibiotics. Beta-defensins play a crucial role in host defense against pathogens and have multifunctional properties, exerting key roles in innate and adaptive immunity, as well as non-immune processes. In this study, a 210 bp long cDNA sequence of yak DEFB114 gene was amplified and successfully expressed in a prokaryotic system. The DEFB114 protein exhibited significant inhibitory effects on the growth of Aspergillus fumigatus in vitro. When co-cultured with yak macrophages, DEFB114 protein enhanced macrophage phagocytic activity and increased nucleic acid fluorescence intensity (P < 0.05). DEFB114 protein also enhanced the activity of yak macrophages stimulated by inactivated Aspergillus fumigatus spores, increased the release of nitric oxide (NO), and promoted the expression of genes such as γ-actin, Lgals, Man2b, and Capg (P < 0.05). In mice experiments, DEFB114 protein promoted resistance against Aspergillus fumigatus infection, by regulating the NOD1/2-ATG16L1-NF-κB pathway to modulate the host immune response and exert its anti-infective effects. In summary, the yak DEFB114 protein could inhibit the growth of Aspergillus fumigatus and enhance the animal's resistance to pathogenic microorganisms, thereby having significant implications in the treatment and prevention of fungal infections.

Evaluation of palmatine as an immunostimulant in diet for genetically improved farmed tilapia (GIFT, Oreochromis niloticus)

Palmatine as a medicinal herbs extract has strong bacteriostatic ability and is a promising source of antibacterial additive. The objective of this study was to assess the feasibility of palmatine as an antibiotic alternative in diet for genetically improved farmed tilapia (GIFT, Oreochromis niloticus). Four experimental diets were formulated with 0, 200, 400, and 800 mg/kg palmatine. Tilapia with consistent size (initial body weight 3.43 ± 0.02 g) were fed the test diets twice daily for ten weeks. Dietary palmatine inclusion regardless of levels unaffected the growth performance and feed efficiency (P > 0.05). However, dietary 200–800 mg/kg palmatine inclusion reduced the levels of total cholesterol and low-density lipoprotein cholesterol as well as the ratios of low-density/high-density lipoprotein cholesterol and aspartate/alanine aminotransferase in serum (P < 0.05), but generally improved the antioxidant-related enzymes activities in intestine, plasma and liver, the immunoglobulin M, complement 3, and complement 4 contents and lysozyme activity in plasma, and the phagocytic activity of macrophages in head kidney. Bacterial challenge test demonstrated that dietary supplementation with 200–800 mg/kg palmatine enhanced the resistance of tilapia to Aeromonas hydrophila, and the relative percentage survival was the highest in fish fed diet with 400 mg/kg palmatine. In conclusion, dietary palmatine supplementation enhanced the antioxidant and innate immune responses as well as the resistance against A. hydrophila without compromising growth performance of tilapia, and the suitable inclusion level of palmatine was 400 mg/kg of diet for tilapia.

Analysis of the effects of β-mannanase on immune function and intestinal flora in broilers fed the low energy diet based on 16S rRNA sequencing and metagenomic sequencing

As an enzyme, β-mannanase (BM) can be widely used as feed additive to improve the growth performance of animals. This experiment aimed to determine the effect of the addition of BM to low-energy diet on the immune function and intestinal microflora of broiler chickens. In this study, 384 one-day-old Arbor Acres broilers were randomly divided into 3 groups (8 replicates per group): positive control (PC, received a corn-soybean meal basal diet), negative control (NC, received a low-energy diet with Metabolizable Energy (ME) reduced by 50 kcal/kg) and NC + BM group (NC birds + 100 mg/kg BM). All birds were raised for 42 d. The results showed that BM mitigated the damage of immune function in peripheral blood of broilers caused by the decrease of dietary energy level by increasing the Concanavalin A (Con A) index of stimulation (SI) and macrophages phagocytic activity in the peripheral blood of broilers at 42 d (P < 0.05). The analysis of cecum flora showed that the low-energy diet significantly reduced the observed_species index (P < 0.01), Chao1 index and ACE index (P < 0.05), which reduced the abundance and evenness of species in the cecum of broilers at 21 d. It also significantly reduced the relative abundance of Candidatus_Arthromitus and significantly increased the relative abundance of Pseudomonas in the cecum of broilers at 21 d, while also significantly increasing the relative abundance of Monoglobus at 42 d. BM significantly increased the relative abundance of Lachnospiraceae_UCG-001 and Lachnospiraceae_bacterium_615 in the cecum of broilers at 21 d. In addition, BM inhibited microbial Fatty acid degradation by decreasing the activity of glutaryl-CoA dehydrogenase. Collectively, BM could improve intestinal health by enhancing the immune function of broilers, promoting the proliferation of beneficial bacteria and reducing the number of harmful bacteria, regulating intestinal flora, thereby alleviating the adverse effects of lower dietary energy levels.

Ultrasound-assisted polysaccharide extraction from Fritillaria ussuriensis Maxim. and its structural characterization, antioxidant and immunological activity

Fritillaria ussuriensis Maxim. (F.M.) has been widely used in both food and medication for more than 2000 years. In order to achieve its comprehensive utilization and investigate the structural characterization and biology activity, response surface methodology (RSM) was used to optimize the ultrasound-assisted extraction conditions of F.M. polysaccharides. The optimal extraction conditions were ultrasonic power of 174.2 W, ratio of liquid to material of 40.7 mL/g and ultrasonic time of 82.0 min. In addition, a neutral polysaccharide F-1 was obtained, and its structure characterization, antioxidant and immunological activity were evaluated. The structural properties of the polysaccharide were characterized by UV, IR, GC-MS, NMR and AFM. Monosaccharide composition of F-1 (MW 18.11 kDa) was rhamnose, arabinose, glucosamine hydrochloride, galactose, and glucose which under the ratio of 0.9: 3.8: 0.2: 2.9: 92.2. The fractions of F-1 were mainly linked by → 6)-α-D-Glcp-(1 → with branch chain α-D-Glcp-(1 → 4)-α-D-Glcp-(1 → and 4,6)-α-D-Glcp-(1 → residues. Moreover, F-1 has a significant scavenging activity, which can clear hydroxyl radicals, superoxide anion, DPPH and ABTS. In addition, the immunological activity showed that F-1 had an effect on macrophage phagocytic activity. And it can increase the release of inflammatory factors including TNF-α, IL-1β and IL-6. F-1 is a novel polysaccharide with significant activity in antioxidant and immunological activity, which has great potential for antioxidant and immunizer in food, pharmaceutical and cosmetic industries. The study can provide a methodological basis for polysaccharide research and theoretical basis for the industrialized production and practical application.

Chitosan alleviates ovarian aging by enhancing macrophage phagocyte-mediated tissue homeostasis

BackgroundAge-related changes in the ovarian microenvironment are linked to impaired fertility in women. Macrophages play important roles in ovarian tissue homeostasis and immune surveillance. However, the impact of aging on ovarian macrophage function and ovarian homeostasis remains poorly understood.MethodsSenescence-associated beta-galactosidase staining, immunohistochemistry, and TUNEL staining were used to assess senescence and apoptosis, respectively. Flow cytometry was employed to evaluate mitochondrial membrane potential (MMP) and apoptosis in granulosa cells lines (KGN), and macrophages phagocytosis. After a 2-month treatment with low molecular weight Chitosan (LMWC), ovarian tissues from mice were collected for comprehensive analysis.ResultsCompared with the liver and uterus, the ovary displayed accelerated aging in an age-dependent manner, which was accompanied by elevated levels of inflammatory factors and apoptotic cells, and impaired macrophage phagocytic activity. The aged KGN cells exhibited elevated reactive oxygen species (ROS) and apoptotic levels alongside decreased MMP. H2O2-induced aging macrophages showed reduced phagocytosis function. Moreover, there were excessive aging macrophages with impaired phagocytosis in the follicular fluid of patients with diminished ovarian reserve (DOR). Notably, LMWC administration alleviated ovarian aging by enhancing macrophage phagocytosis and promoting tissue homeostasis.ConclusionsAging ovarian is characterized by an accumulation of aging and apoptotic granulosa cells, an inflammatory response and macrophage phagocytosis dysfunction. In turn, impaired phagocytosis of macrophage contributes to insufficient clearance of aging and apoptotic granulosa cells and the increased risk of DOR. Additionally, LMWC emerges as a potential therapeutic strategy for age-related ovarian dysfunction.

The effect of natural ingredients extracts on the phagocytosis index of the carbon clearance animal models

The immune system has a very important role to fight foreign substances in the body. Immunostimulants are needed to stimulate the activity of the immune system and immunosuppressants are needed to suppress the immune system. The aims of this study is to evaluate phagocitytosis index of several natural ingredient extract using carbon clearance method. The natural ingredients are the ethanol extract of Ageratum conyzoides leaves 160 mg/kgBW, ethanol extract of Artocarpus heterophyllus leaves 500 mg/kgBW, ethanol extract of Nephelium lappaceum peel 650 mg/kgBW, ethanol extract of Cucurbita moschata seed 342 mg/kgBW and ethanol extract of Citrullus lanatus rind 55 mg/kgBW. Tests were carried out on male mice Balb/C strains using the carbon clearance method, where colloidal carbon ink acts as an antigen. The phagocytic activity of macrophages in eliminating carbon ink was measured based on the stimulation index value and then the immunomodulatory effect was classified according to Wagner's criteria. The stimulation index of A.heterophyllus was 1.423; A. conyzoides was 1.201; N. lappaceum was 1.236; C.lanatus was 0.909 and C. moschata was 1.299. The potential extract as immunostimulant was A.heterophyllus, as immunosupressant was C. lanatus. A.conyzoides and probably had no effect (act as imunorestorant) and C. moschata 342 mg/kgBW had slight immunostimulant effect.

Semaphorin3B promotes an anti-inflammatory and pro-resolving phenotype in macrophages from rheumatoid arthritis patients in a MerTK-dependent manner.

Previous works from our group show that Semaphorin3B (Sema3B) is reduced in RA and plays a protective role in a mouse arthritis model. In turn, MerTK plays a protective function in murine arthritis models, is expressed by synovial tissue macrophages and is linked to remission in patients with RA. In this study, we examined the role of Sema3B in the phenotypic characteristics of RA macrophages and the implication of MerTK. Peripheral blood monocytes from RA patients were differentiated into IFN-γ (RA MØIFN-γ) or M-CSF (RA MØM-CSF) macrophages and stimulated with LPS, Sema3B or their combination. Alternatively, RA fibroblast like synoviocytes (FLS) were stimulated with RA MØIFN-γ and RA MØM-CSF supernatants. Gene expression was determined by qPCR and protein expression and activation by flow cytometry, ELISA and western blot. Sema3B down-regulated the expression of pro-inflammatory mediators, in both RA MØIFN-γ and RA MØM-CSF. We observed a similar reduction in RA FLS stimulated with the supernatant of Sema3B-treated RA MØIFN-γ and RA MØM-CSF. Sema3B also modulated cell surface markers in macrophages towards an anti-inflammatory phenotype. Besides, MerTK expression and activation was up-regulated by Sema3B, just as GAS6 expression, Resolvin D1 secretion and the phagocytic activity of macrophages. Importantly, the inhibition of MerTK and neuropilins 1 and 2 abrogated the anti-inflammatory effect of Sema3B. Our data demonstrate that Sema3B modulates the macrophage characteristics in RA, inducing a skewing towards an anti-inflammatory/pro-resolving phenotype in a MerTK-dependant manner. Therefore, here we identify a new mechanism supporting the protective role of Sema3B in RA pathogenesis.

Cold Alkali-Extractable Antioxidative Polysaccharide from Russula pseudocyanoxantha (Agaricomycetes), a Novel Mushroom, Stimulates Immune Responses in RAW264.7 Cells by Regulating the TLR/NF-κB Pathway.

In our previous study, we have established Russula pseudocyanoxantha as a unique species, playing a crucial role in indigenous diets through ages. The research also brought attention to bioactive potential of polysaccharide fraction extracted from the unexplored food using hot water. However, residue of the conventional process still contains therapeutic biopolymers that could further be utilized for pharmacological purposes instead of being discarded. Therefore, the current study aims to valorize the solid remnants, contributing to a deeper understanding of the novel taxon. Subsequently, the leftover was treated with cold alkali, leading to the preparation of a high-yield fraction (RP-CAP). Chemical characterization through FT-IR, GC-MS, HPTLC, and spectroscopy demonstrated presence of several monomers in the carbohydrate backbone, predominantly composed of β-glucan. Furthermore, GPC chromatogram indicated presence of a homogeneous polymer with molecular weight of ~ 129.28 kDa. Subsequently, potent antioxidant activity was noted in terms of radical scavenging (O2·-, OH·, DPPH· and ABTS·+), chelating ability, reducing power and total antioxidant activity where EC50 values ranged from 472-3600 μg/mL. Strong immune-boosting effect was also evident, as the biopolymers stimulated murine macrophage cell proliferation, phagocytic activity, pseudopod formation, and NO as well as ROS synthesis particularly at the concentration of 100 μg/mL. In-depth analysis through RT-PCR revealed that the fraction stimulated synthesis of several inflammatory mediators, elucidating the mode of action through TLR/ NF-κB pathway. Therefore, the findings collectively suggest that RP-CAP possesses great potential to serve as a healthimproving component in functional food and pharmaceutical sectors.

Moesin affects the plasma membrane expression and the immune checkpoint function of CD47 in human ovarian clear cell carcinoma

Among major histological subtypes of epithelial ovarian cancer, a higher incidence of ovarian clear cell carcinoma (OCCC) is observed in East Asian populations, particularly in Japan. Despite recent progress in the immune checkpoint inhibitors for a wide variety of cancer cell types, patients with OCCC exhibit considerably low response rates to these drugs. Hence, urgent efforts are needed to develop a novel immunotherapeutic approach for OCCC. CD47, a transmembrane protein, is overexpressed in almost all cancer cells and disrupts macrophage phagocytic activity in cancer cells. Ezrin-Radixin-Moesin (ERM) family member of proteins serve as scaffold proteins by crosslinking certain transmembrane proteins with the actin cytoskeleton, contributing to their plasma membrane localization. Here, we examined the role of ERM family in the plasma membrane localization and functionality of CD47 in OCCC cell lines derived from Japanese women. Confocal laser scanning microscopy analysis showed colocalization of CD47 with all three ERM in the plasma membrane of OCCC cells. RNA interference-mediated gene silencing of moesin, but not others, decreased the plasma membrane expression and immune checkpoint function of CD47, as determined by flow cytometry and in vitro phagocytosis assay using human macrophage-like cells, respectively. Interestingly, clinical database analysis indicated that moesin expression in OCCC was higher than that in other histological subtypes of ovarian cancers, and the expression of CD47 and moesin increased with the cancer stage. In conclusion, moesin is overexpressed in OCCC and may be the predominant scaffold protein responsible for CD47 plasma membrane localization and function in OCCC.

Radio-chemotherapy of glioblastoma cells promotes phagocytosis by macrophages in vitro

Background and PurposeImmunotherapy is actively explored in glioblastoma (GBM) to improve patient prognosis. Tumor-associated macrophages (TAMs) are abundant in GBM and harnessing their function for anti-tumor immunity is of interest. They are plastic cells that are influenced by the tumor microenvironment, by radio-chemotherapy and by their own phagocytic activity. Indeed, the engulfment of necrotic cells promotes pro-inflammatory (and anti-tumoral) functions while the engulfment of apoptotic cells promotes anti-inflammatory (and pro-tumoral) functions through efferocytosis. Materials and MethodsTo model the effect of radio-chemotherapy on the GBM microenvironment, we exposed human macrophages to supernatant of treated GBM cells in vitro. Macrophages were derived from human monocytes and GBM cells from patient-resected tumors. GBM cells were exposed to therapeutically relevant doses of irradiation and chemotherapy. Apoptosis and phagocytic activity were assessed by flow cytometry. ResultsThe phagocytic activity of macrophages was increased, and it was correlated with the proportion of apoptotic GBM cells producing the supernatant. Whether uptake of apoptotic tumor cells could occur would depend upon the expression of efferocytosis-associated receptors. Indeed, we showed that efferocytosis-associated receptors, such as AXL, were upregulated. Conclusions and PerspectivesWe showed that macrophage phagocytic activity increased when exposed to supernatant from GBM cells treated by radio-chemotherapy. However, as efferocytosis-associated receptors were up-regulated, this effect could be deleterious for the anti-GBM immune response. We speculate that by inducing GBM cell apoptosis in parallel to an increase in efferocytosis receptor expression, the impact of radio-chemotherapy on phagocytic activity could promote anti-inflammatory and pro-tumoral TAM functions.

Preliminary study of immunomodulatory effects of fermented garlic honey on non-specific immune responses

Introduction: Honey and Garlic is recognized to offer several health advantages due to its numerous constituents, one of which being flavonoids. Flavonoids’ pharmacological activity includes antibacterial, antioxidant, antifungal, antiviral, and immunomodulatory properties. Honey's immunomodulatory action plays a vital role in immune system boosting. The purpose of this study is to determine the immunomodulatory effect of fermented garlic honey, which is considered to have a synergistic effect, using two alternative techniques. Methods: Macrophage phagocytic activity is the first approach, while the delayed type hypersensitivity is the second. Each method used 30 male rats (Rattus norvegicus) divided into 5 groups, where each group consisted of 6 rats. Group I negative (Placebo 0,005 g/kg BW), group II positive (Stimuno 0,005 g/kg BW), group III FGH dose I (1,5 g/kg BW), group IV FGH dose II (3 g/kg BW), group V FGH dose III (4,5 g/kg BW). The dosage form was orally given for 21 days. The Macrophage phagocytic activity method measured %activity of macrophage phagocytosis using a microscope. The rats were injected with an antigen which is Staphylococcus aureus by intraperitoneal route. Results: The Delayed Type Hypersensitivity was measured volume change of the rat’s feet at the 4, 24, and 48 hours using a plethysmometer. Based on the results, fermented garlic honey had an immunomodulatory effect. The dose 2 (3 g/kg BW) has the highest effectiveness as an immunomodulator. Fermented Garlic Honey may be concluded to be efficient as an immunomodulator by enhancing the macrophage phagocytic activity indicator and lowering the edema volume of the rat. Conclusion: Fermented garlic honey can increase the immune system and can be used as an immunostimulant. The most effective dose of fermented garlic honey as immunomodulator is dose 2 was 3 g/kg BW.

Sting Activation in Bone Marrow Macrophages Targets AML Blasts for Phagocytosis in an ICAM-1 Dependent Mechanism

The initiation and proliferation of acute myeloid leukaemia (AML) is in part regulated by the bone marrow microenvironment. Previous work by our group has shown that the stimulator of interferon genes (STING) pathway is activated in macrophages in the AML bone marrow microenvironment (Moore et al., 2022) . We found that AML-derived mitochondrial damage-associated molecular patterns were processed by bone marrow macrophages (BMMs) via LC3-associated phagocytosis (LAP). Furthermore, activation of STING resulted in a suppression of AML growth through an LAP dependent mechanism. Here we have investigated how the activation of STING in bone marrow macrophages increases macrophage phagocytic activity and in turn supresses the growth of AML. To understand the role of STING activation in bone marrow derived macrophages (BMDMs) in AML we used various STING agonists including DMXAA, 2'3'-cGAMP, and CpG oligonucleotides. We showed STING activation was induced through these agonists by measuring the upregulation of STING related genes ( Gbp2, Irf7 and Ifit3). We demonstrated that STING activation caused increased phagocytic clearance of live MN1 cells (mouse AML cell line) in an in vitro phagocytosis assay. In order to investigate how STING activation increases the phagocytic clearance of AML cells by BMDMs, we used three complementary methods. First, we performed a receptor tyrosine kinase array to measure the phosphorylation of mouse kinases following STING activation. Second, we investigated the transcriptomic changes resulting from STING activation with mRNA-sequencing. Third, after combining these results we identified an upregulation of key phagocytic pathways that specifically led us to focus on the adhesion molecules, in particular ICAM-1. Further investigation using an anti-ICAM-1 blocking antibody showed a reduction in the phagocytic potential of the BMDMs demonstrating the role of ICAM-1 in the phagocytic clearance of AML. Next, we activated human macrophages (derived from peripheral blood monocytes collected from healthy donors with approval of the East of England - Cambridgeshire and Hertfordshire Research Ethics Committee and the UK Health Research Authority, IRAS Project ID 33753) through STING which depleted AML in vitro confirming the results obtained using the mouse system. To investigate the in vivo significance of these findings, we treated C57Bl/6 animals with DMXAA and observed a significantly decreased tumour burden and increased survival following engraftment with MN1 cells. Cytotoxic T cell activity and number in the bone marrow was unchanged by STING activation in this model. In summary, we have shown that the activation of STING in bone marrow macrophages directly supresses the growth and proliferation of AML by stimulating the phagocytic activity of the macrophages, and the clearance of the leukaemic cells.

Biomimetic Nanocarriers of Pro-Resolving Lipid Mediators for Resolution of Inflammation in Atherosclerosis.

Atherosclerosis (ATH) is a systemic disease characterized by a chronic inflammatory process and lipid deposition in the arterial walls. The chronic inflammation within ATH lesions results, at least in part, from the failed resolution of inflammation. This process is controlled actively by specialized pro-resolving lipid mediators (SPMs), namely lipoxins, resolvins, protectins, and maresins. Herein, biomimetic nanocarriers are produced comprising a cocktail of SPMs-loaded lipid nanoemulsions (LN) covered with macrophage membranes (Bio-LN/SPMs). Bio-LN/SPMs retain on their surface the macrophage receptors involved in cellular interactions and the "marker of self" CD47, which impede their recognition and uptake by other macrophages. The binding of Bio-LN/SPMs to the surface of endothelial cells (EC) and smooth muscle cells (SMC) is facilitated by the receptors on the macrophage membranes and partly by SPMs receptors. In addition, Bio-LN/SPMs prove functional by reducing monocyte adhesion and transmigration to/through activated EC and by stimulating macrophage phagocytic activity. After intravenous administration, Bio-LN/SPMs accumulate in the aorta of ApoE-deficient mice at the level of atherosclerotic lesions. Also, the safety assessment testing reveals no side effects or immunotoxicity of Bio-LN/SPMs. Thus, the newly developed Bio-LN/SPMs represent a reliable targeted nanomedicine for the resolution of inflammation in atherosclerosis.

Adipose stromal cells bioproducts as cell-free therapies: manufacturing and therapeutic dose determine in vitro functionality

BackgroundExtracellular vesicles (EV) are considered a cell-free alternative to mesenchymal stromal cell (MSC) therapy. Numerous reports describe the efficacy of EV in conferring immunomodulation and promoting angiogenesis, yet others report these activities to be conveyed in EV-free bioproducts. We hypothesized that this discrepancy may depend either on the method of isolation or rather the relative impact of the individual bioactive components within the MSC secretome.MethodsTo answer this question, we performed an inter-laboratory study evaluating EV generated from adipose stromal cells (ASC) by either sequential ultracentrifugation (UC) or size-exclusion chromatography (SEC). The effect of both EV preparations on immunomodulation and angiogenesis in vitro was compared to that of the whole secretome and of the EV-free protein fraction after SEC isolation.ResultsIn the current study, neither the EV preparations, the secretome or the protein fraction were efficacious in inhibiting mitogen-driven T cell proliferation. However, EV generated by SEC stimulated macrophage phagocytic activity to a similar extent as the secretome. In turn, tube formation and wound healing were strongly promoted by the ASC secretome and protein fraction, but not by EV. Within the secretome/protein fraction, VEGF was identified as a potential driver of angiogenesis, and was absent in both EV preparations.ConclusionsOur data indicate that the effects of ASC on immunomodulation and angiogenesis are EV-independent. Specific ASC-EV effects need to be dissected for their use as cell-free therapeutics.

Andrographolide Attenuates Inflammation Due to Intra-Abdominal Sepsis by Enhancing Bacterial Clearance in Mice.

Intra-abdominal infection is a complex pathophysiological process involving multiple systems and organs of the body. Abdominal infections complicated by severe sepsis or septic shock have a high mortality rate of 30-50%. Therefore, novel strategies to treat sepsis are urgently needed. Andrographolide (AD), the main active ingredient of Andrographis paniculata, reportedly exerts beneficial effects on mice with sepsis. However, its exact mechanism of action in attenuating inflammation due to intra-abdominal sepsis remains unclear to date. Hence, this study aimed to examine the therapeutic effects of AD on cecal ligation and puncture (CLP)-induced sepsis and elucidate the underlying mechanisms. Results showed that AD therapy could significantly improve the 7-day survival rate and alleviate pathological organ injury in mice with CLP. In addition, AD treatment decreased the levels of proinflammatory factors, such as tumor necrosis factor-α and interleukin (IL)-6 in the peritoneal cavity fluid and blood and increased the level of anti-inflammatory factor IL-10 in the peritoneal cavity fluid of mice with CLP. Moreover, bacterial counts in the blood and peritoneal lavage fluid were lower in the mice treated with AD than in those untreated. Mechanistically, AD treatment increased the percentage and phagocytic activity of macrophages in the peritoneal cavity. These data showed that AD can improve the survival of mice with intra-abdominal sepsis by enhancing bacterial clearance, as evidenced by the increased percentages and phagocytic activity of macrophages in the peritoneal cavity. This study is the first to demonstrate the protective effects of AD against intra-abdominal sepsis.

Immunostimulatory activity of avocado oil in mice (Mus musculus)

Avocado fruit contains bioactive compounds that have the potential to act as an immunomodulator. This study aims to identify the ability of avocado oil as an immunomodulator based on the macrophage phagocytic activity and index of mice injected with nonpathogenic Staphylococcus aureus and to determine the most effective dose as an immunomodulator. This study used 30 male Deutschland Denken Yoken (DDY) mice, which were divided into five groups: placebo as negative control (mineral water), positive control (commercial immunomodulator containing Echinacea purpurea extract), and avocado oil 1 g/kg BW, 3 g/kg BW, and 5 g/kg BW. The treatment was carried out orally once a day for 14 days. Mice were induced by nonpathogenic Staphylococcus aureus on day 15 intraperitoneally, and after one hour, mice were euthanized to collect the peritoneal fluid. Peritoneal fluid smear preparations were made before active macrophages and phagocytosed Staphylococcus aureus were observed under a microscope. Phagocytic activity and phagocytic index were calculated. Avocado oil 5 g/kg BW showed the highest phagocytic activity and phagocytic index results with values of 71.00% ± 5.40% and 2.79 ± 0.14, respectively. Avocado oil enhances non-specific immune responses through macrophagephagocytic activity and index, demonstrating its immunostimulatory potential.

Heterogeneity in macrophages along the cochlear spiral in mice: insights from SEM and functional analyses.

The susceptibility of sensory cells to pathological conditions differs between the apical and basal regions of the cochlea, and the cochlear immune system may contribute to this location-dependent variability. Our previous study found morphological differences in basilar membrane macrophages between the apical and basal regions of the cochlea. However, the details of this site-dependent difference and its underlying structural and biological basis are not fully understood. In this study, we utilized scanning electron microscopy to examine the ultrastructure of macrophages and their surrounding supporting structures. Additionally, we examined the phagocytic activities of macrophages and the expression of immune molecules in both apical and basal regions of the cochlea. We employed two mouse strains (C57BL/6J and B6.129P-Cx3cr1tm1Litt/J) and evaluated three experimental conditions: young normal (1-4 months), aging (11-19 months), and noise-induced damage (120 dB SPL for 1 h). Using scanning electron microscopy, we revealed location-specific differences in basilar membrane macrophage morphology and surface texture, architecture in mesothelial cell layers, and spatial correlation between macrophages and mesothelial cells in both young and older mice. Observations of macrophage phagocytic activities demonstrated that basal macrophages exhibited greater phagocytic activities in aging and noise-damaged ears. Furthermore, we identified differences in the expression of immune molecules between the apical and basal cochlear tissues of young mice. Finally, our study demonstrated that as the cochlea ages, macrophages in the apical and basal regions undergo a transformation in their morphologies, with apical macrophages acquiring certain basal macrophage features and vice versa. Overall, our findings demonstrate apical and basal differences in macrophage phenotypes and functionality, which are related to distinct immune and structural differences in the macrophage surrounding tissues.