Phagocytosis Activity Research Articles

Elemental composition of sputum, immune status, and features of pharyngeal microbiota in workers of the anode department of a copper smelter

The development of bronchial and pulmonary pathology depends on characteristics of the aerosols and individual resistance of the body, largely determined by the immune system, to their exposure. Mucous membranes of a healthy person are colonized by saprophytic bacteria or normal microbiota. Yet, changes in the composition and properties of the microbial landscape induced by adverse environmental factors increase the risk of inflammation and contribute to changes in the reactivity of the immune system. The study aims to establish the immune status, microbiota of the pharyngeal mucosa, and the elemental composition of sputum, given its cellular composition, in workers of the anode department of a copper smelter. We tested sputum culture and elemental composition, established clinical and immunological status, and analyzed pharyngeal microbiota in 28 workers of the anode department of a copper smelter. Based on the results of testing, the subjects were divided into two groups with (1) and without (2) leukocytosis (>10 cells in the field of view) detected in sputum. We found no acute or chronic diseases of the bronchi and lungs in the examined workers. In group 1, we observed shifts in the immune response manifested by a decrease in the number of immunocompetent cells, activation of neutrophil phagocytosis, formation of reactive oxygen species in neutrophils, and displacement of normal microbiota of the oropharyngeal mucosa by opportunistic microorganisms (in 100% versus 35%, p<0.05). The elemental composition of sputum was noted for a higher frequency of iron and lead detection and increased concentrations of barium, lead, iron, arsenic, molybdenum, antimony, vanadium, and cadmium. We established a significant effect of metals contained in sputum on cellular, humoral, and local immunity. The inflammatory bronchopulmonary response to toxic aerosol exposure is accompanied by changes in the cellular and phagocytic links of immunity, as well as in the microbial landscape on the mucous membrane of the upper respiratory tract characterized by displacement of normal biota by opportunistic microorganisms. Limitations. This study has certain limitations associated with the small sample size and the lack of opportunity to compare metal concentrations found in sputum with reference levels. Ethics. The study was approved by the Local Ethics Committee of the Yekaterinburg Medical Research Center for Prophylaxis and Health Protection in Industrial Workers (extract from the minutes of the meeting No. 8 dated 12/26/2016).

Plant-produced SARS-CoV-2 antibody engineered towards enhanced potency and in vivo efficacy.

Prevention of severe COVID-19 disease by SARS-CoV-2 in high-risk patients, such as immuno-compromised individuals, can be achieved by administration of antibody prophylaxis, but producing antibodies can be costly. Plant expression platforms allow substantial lower production costs compared to traditional bio-manufacturing platforms depending on mammalian cells in bioreactors. In this study, we describe the expression, production and purification of the originally human COVA2-15 antibody in plants. Our plant-produced mAbs demonstrated comparable neutralizing activity with COVA2-15 produced in mammalian cells. Furthermore, they exhibited similar capacity to prevent SARS-CoV-2 infection in a hamster model. To further enhance these biosimilars, we performed three glyco- and protein engineering techniques. First, to increase antibody half-life, we introduced YTE-mutation in the Fc tail; second, optimization of N-linked glycosylation by the addition of a C-terminal ER-retention motif (HDEL), and finally; production of mAb in plant production lines lacking β-1,2-xylosyltransferase and α-1,3-fucosyltransferase activities (FX-KO). These engineered biosimilars exhibited optimized glycosylation, enhanced phagocytosis and NK cell activation capacity compared to conventional plant-produced S15 and M15 biosimilars, in some cases outperforming mammalian cell produced COVA2-15. These engineered antibodies hold great potential for enhancing in vivo efficacy of mAb treatment against COVID-19 and provide a platform for the development of antibodies against other emerging viruses in a cost-effective manner.

Alzheimer’s disease-associated protective variant Plcg2-P522R modulates peripheral macrophage function in a sex-dimorphic manner

Genome-wide association studies have identified a protective mutation in the phospholipase C gamma 2 (PLCG2) gene which confers protection against Alzheimer’s disease (AD)-associated cognitive decline. Therefore, PLCG2, which is primarily expressed in immune cells, has become a target of interest for potential therapeutic intervention. The protective allele, known as P522R, has been shown to be hyper-morphic in microglia, increasing phagocytosis of amyloid-beta (Aβ), and increasing the release of inflammatory cytokines. However, the effect of this protective mutation on peripheral tissue-resident macrophages, and the extent to which sex modifies this effect, has yet to be assessed. Herein, we show that peripheral macrophages carrying the P522R mutation do indeed show functional differences compared to their wild-type (WT) counterparts, however, these alterations occur in a sex-dependent manner. In macrophages from females, the P522R mutation increases lysosomal protease activity, cytokine secretion, and gene expression associated with cytokine secretion and apoptosis. In contrast, in macrophages from males, the mutation causes decreased phagocytosis and lysosomal protease activity, modest increases in cytokine secretion, and induction of gene expression associated with negative regulation of the immune response. Taken together, these results suggest that the mutation may be conferring different effects dependent on sex and cell type, and highlight the importance of considering sex as a biological variable when assessing the effects of genetic variants and implications for potential immune system-targeted therapies.

A multi-comprehensive approach to assess the responses of the Mediterranean mussel Mytilus galloprovincialis (Lamarck, 1919) to a simulation of a diesel-oil mixture spill

Oil spills are a major cause of pollution impacting marine ecosystems. In this work, the effects of short-term exposure to three different concentrations of a hydrocarbon mixture (HC) that simulated the action of such an event were investigated on Mytilus galloprovincialis specimens. Physiological effects were measured using a battery of biomarkers consisting of cellular activity (phagocytosis), immune-related enzymes, chaperonins (HSP70 and HSC70), and histomorphological alterations. Different concentrations of HC led to a significant decrease in phagocytosis, especially following high concentrations. Immune-related enzymes evaluated in hemolymph and digestive gland extract showed up-regulation, suggesting the activation of antioxidant, detoxicant, and inflammatory responses. Morphological alterations of digestive gland tubules were observed after exposure to the HC. HSP70 and HSC70 activity was up regulated following the treatments, indicating their involvement in maintaining organism homeostasis. In addition, the diversity and composition of hemolymph and digestive gland microbiota exposed to HC were analyzed by automated ribosomal intergenic spacer analysis (ARISA) and a Next Generation Sequencing (NGS) approach to evaluate the connection with hydrocarbon contamination. Metagenomic analysis revealed significant differences in the hemolymph and digestive gland microbiota composition between mussels exposed and unexposed to HC. Exposure to increasing HC concentrations had a positive effect on microbial diversity with clear adaptative responses, an increase in the relative abundance of several known degrading bacterial genera, including Alcanivorax, Roseovarius, Pseudomonas, Vibrio, Oleibacter. These results show the utility of a multi-comprehensive approach to evaluating functional adaptation in terms of immunological dysfunctions and microbiota alteration in the sentinel organism M. galloprovincialis.

Immuno- and gut microbiota-modulatory activities of β-1,6-glucans from Lentinus edodes

The β-1,6-glucans from Lentinus edodes have a variety of biological activities. However, the research on extraction and separation of β-1,6-glucans from L. edodes is limited and the yield is low. In the present study, we obtained the high-yield and -purity β-1,6-glucans (ALEPA) from L. edodes by using a sequential extraction and separation process, which is simple and suitable for industrialization. ALEPA significantly promoted the proliferation of splenic T lymphocytes and enhanced the phagocytosis activity of peritoneal macrophages in vivo. 16S rRNA sequencing results showed that ALEPA significantly increased the α diversity of gut microbiota and upregulated the relative abundances of short chain fatty acids (SCFAs)-producing bacterial species. Consistently, the SCFAs in the cecum of mice were upregulated. On a mechanical level, we found that the immunomodulatory effect of ALEPA depended on gut microbiota. Collectively, ALEPA is a promising functional food ingredient that regulates gut microbiota and enhances immune function.

Neoadjuvant vidutolimod and nivolumab in high-risk resectable melanoma: A prospective phase II trial

Intratumoral TLR9 agonists and anti-PD-1 produce clinical responses and broad immune activation. We conducted a single-arm study of neoadjuvant TLR9 agonist vidutolimod combined with anti-PD-1 nivolumab in high-risk resectable melanoma. In 31 evaluable patients, 55% major pathologic response(MPR) was observed, meeting primary endpoint. MPR was associated with necrosis, and melanophagocytosis with increased CD8+ tumor-infiltrating lymphocytes and plasmacytoid dendritic cells (pDCs) in the tumor microenvironment, and increased frequencies of Ki67+CD8+ Tcells peripherally. MPRs had an enriched pre-treatment gene signature of myeloid cells, and response to therapy was associated with gene signatures of immune cells, pDCs, phagocytosis, and macrophage activation. MPRs gut microbiota were enriched for Gram-negative bacteria belonging to the Bacteroidaceae and Enterobacteriaceae families and the small subgroup of Gram-negative Firmicutes. Our findings support that combined vidutolimod and nivolumab stimulates a broad anti-tumor immune response and is associated with distinct baseline myeloid gene signature and gut microbiota. ClinicalTrials.gov identifier: NCT03618641.

Emerging Frontiers in Cancer Immunotherapy: Recent Advances in CAR-NK Cell and CAR-Macrophage Therapies

Chimeric antigen receptor (CAR) cell therapies have revolutionized the field of cancer treatment with the breakthrough successes of CAR-T cell therapy in hematological malignancies. However, CAR-T cell efficacy in solid tumors has been limited by challenges such as the immunosuppressive tumor microenvironment (TME) and safety concerns like cytokine release syndrome (CRS) and graft-versus-host disease (GvHD). This review focuses on the latest advancements in CAR-NK cell and CAR-macrophage therapies, which offer potential solutions to these limitations. CAR-NK cells exhibit natural cytotoxicity and MHC-independent tumor targeting, providing a safer profile with lower risks of GvHD and CRS compared to CAR-T cells. Innovations in CAR-NK cell therapy includes structural optimizations, gene editing with CRISPR-Cas9, and the development of multispecific CARs, all contributing to enhanced anti-tumor efficacy, especially in solid tumors. Meanwhile, CAR-macrophages are effective in remodeling the TME through phagocytosis and immune activation, addressing the challenges of solid tumor infiltration. This review compares the mechanisms of action, clinical applications, and safety profiles of CAR-NK cells and CAR-macrophages, highlighting the synergistic potential of these therapies. Although clinical research on both therapies is still in its early stages, the promising preclinical and early clinical trial results underscore their potential as alternative immunotherapies for refractory cancers. Future research will focus on overcoming challenges in production scalability, improving in vivo persistence, and personalizing CAR therapies through precision medicine approaches. These two therapies will likely play pivotal roles in the next generation of cancer immunotherapies.

CAR-Macrophage Therapy Alleviates Myocardial Ischemia-Reperfusion Injury.

Given the growing acknowledgment of the detrimental effects of excessive myocardial fibrosis on pathological remodeling after myocardial ischemia-reperfusion injury (I/R), targeting the modulation of myocardial fibrosis may offer protective and therapeutic advantages. However, effective clinical interventions and therapies that target myocardial fibrosis remain limited. As a promising chimeric antigen receptor (CAR) cell therapy, whether CAR macrophages (CAR-Ms) can be used to treat I/R remains unclear. The expression of FAP (fibroblast activation protein) was studied in mouse hearts after I/R. FAP CAR-Ms were generated to target FAP-expressing cardiac fibroblasts in mouse hearts after I/R. The phagocytosis activity of FAP CAR-Ms was tested in vitro. The efficacy and safety of FAP CAR-Ms in treating I/R were evaluated in vivo. FAP was significantly upregulated in activated cardiac fibroblasts as early as 3 days after I/R. Upon demonstrating their ability to engulf FAP-overexpressing fibroblasts, we intravenously administered FAP CAR-Ms to mice at 3 days after I/R and found that FAP CAR-Ms significantly improved cardiac function and reduced myocardial fibrosis in mice after I/R. No toxicities associated with FAP CAR-Ms were detected in the heart or other organs at 2 weeks after I/R. Finally, we found that FAP CAR-Ms conferred long-term cardioprotection against I/R. Our proof-of-concept study demonstrates the therapeutic potential of FAP CAR-Ms in alleviating myocardial I/R and potentially opens new avenues for the treatment of a range of heart diseases that include a fibrotic phenotype.

Immunomodulatory Effects of Citrus Species Ethanol Extracts on Cellular Immune Responses in Wistar Rats and Mice

Currenty, Citrus reticulata has been found to modulate RAW 264.7 macrophage cell line. In the present study, the immunomodulatory effects of Citrus species peel extracts, including Citrus microcarpa, C. limon L., C. sinensis L. and C. hystrix were investigated on cellular immune responses in Wistar rats and mice. Mice were treated with ethanol extracts of Citrus species orally at dosages of 25, 50 and 100 mg/kg bw for 7 days. The phagocytosis activity of the extracts was examined using the carbon clearance method. Meanwhile, oral administration of Citrus species ethanol extracts at dosages of 17.5, 35 and 70 mg/kg bw was administered to Wistar rats to assess the effect of extracts on the delayed-type hypersensitivity (DTH) response using paw edema-method. Thin Layer Chromatography (TLC)-densitometry analysis was also performed. In both animal models, all extracts enhanced the cellular immune responses. Amongst the samples, C. sinensis, at the dose of 100 mg/kg bw in mice and 70 mg/kb bw in rats, demonstrated the highest stimulation on phagocytosis activity and DTH response, respectively. Except C. microcarpa, rutin was found in all Citrus species. The results indicate that Citrus species, particularly C. sinensis, have the potential to be developed into a potent immunostimulatory agent. HIGHLIGHTS The immunomodulatory effects Citrus species were investigated using mice and rats as animal models. Citrus microcarpa, C. limon, C. sinensis L. and C. hystrix were able to stimulate phagocytosis in mice and delayed-type hypersensitivity response in rats. Citrus sinensis demonstrated the highest stimulation on phagocytosis activity and delayed-type hypersensitivity response. Rutin was found in all Citrus species, except in microcarpa peels extract. GRAPHICAL ABSTRACT

The role of lipids in regulating macrophage antifungal immunity.

Macrophages are critical components of the antifungal immune response. Disturbance in the number or function of these innate immune cells can significantly increase susceptibility to invasive fungal infections. Pathogenic fungi cause billions of infections every year and have an unmet clinical need, with many infections associated with unacceptably high mortality rates that primarily affect vulnerable patients with underlying immune defects. Lipid metabolism has been increasingly appreciated to significantly influence macrophage function, particularly of macrophages residing in lipid-rich organs, such as the brain, or macrophages specialized at clearing dead cells including alveolar macrophages in the lungs. In this review, we provide an overview of macrophage lipid metabolism, and discuss how lipid recycling and dysregulation affect key macrophage functions relevant for antifungal immunity including phagocytosis, functional polarization, and inflammasome activation. We focus on the fungal pathogen Cryptococcus neoformans, as this is the most common cause of death from fungal infection in humans and because several lines of evidence have already linked lipid metabolism in the regulation of C. neoformans and macrophage interactions.

Staphylococcus aureus SaeRS impairs macrophage immune functions through bacterial clumps formation in the early stage of infection

The Staphylococcus aureus (S. aureus) SaeRS two-component system (TCS) regulates over 20 virulence factors. While its impact on chronic infection has been thoroughly discussed, its role in the early stage of infection remains elusive. Since macrophages serve as the primary immune defenders at the onset of infection, this study investigates the influence of SaeRS on macrophage functions and elucidates the underlying mechanisms. Macrophage expression of inflammatory and chemotactic factors, phagocytosis, and bactericidal activity against S. aureus were assessed, along with the evaluation of cellular oxidative stress. SaeRS was found to impair macrophage function. Mechanistically, SaeRS inhibited NF-κB pathway activation via toll-like receptor 2 (TLR2). Its immune-modulating effect could partially be explained by the strengthened biofilm formation. More importantly, we found SaeRS compromised macrophage immune functions at early infection stages even prior to biofilm formation. These early immune evasion effects were dependent on bacterial clumping as cytokine secretion, phagocytosis, and bactericidal activity were repaired when clumping was inhibited. We speculate that the bacterial clumping-mediated antigen mask is responsible for SaeRS-mediated immune evasion at the early infection stage. In vivo, ΔsaeRS infection was cleared earlier, accompanied by early pro-inflammatory cytokines production, and increased tissue oxidative stress. Subsequently, macrophages transitioned to an anti-inflammatory state, thereby promoting tissue repair. In summary, our findings underscore the critical role of the SaeRS TCS in S. aureus pathogenicity, particularly during early infection, which is likely initiated by SaeRS-mediated bacterial clumping.

Damping excessive viral-induced IFN-γ rescues the impaired anti-Aspergillus host immune response in influenza-associated pulmonary aspergillosis

Influenza-associated pulmonary aspergillosis (IAPA) is a severe fungal superinfection in critically ill influenza patients that is of incompletely understood pathogenesis. Despite the use of contemporary therapies with antifungal and antivirals, mortality rates remain unacceptably high. We aimed to unravel the IAPA immunopathogenesis as a means to develop adjunctive immunomodulatory therapies. We used a murine model of IAPA to investigate how influenza predisposes to the development of invasive pulmonary aspergillosis. Immunocompetent mice were challenged with an intranasal instillation of influenza on day 0 followed by an orotracheal inoculation with Aspergillus 4 days later. Mice were monitored daily for overall health status, lung pathology with micro-computed tomography (μCT) and fungal burden with bioluminescence imaging (BLI). At endpoint, high parameter immunophenotyping, spatial transcriptomics, histopathology, dynamic phagosome biogenesis assays with live imaging, immunofluorescence staining, specialized functional phagocytosis and killing assays were performed. We uncovered an early exuberant influenza-induced interferon-gamma (IFN-γ) production as the major driver of immunopathology in IAPA and delineated the molecular mechanisms. Specifically, excessive IFN-γ production resulted in a defective Th17-immune response, depletion of macrophages, and impaired killing of Aspergillus conidia by macrophages due to the inhibition of NADPH oxidase-dependent activation of LC3-associated phagocytosis (LAP). Markedly, mice with partial or complete genetic ablation of IFN-γ had a restored Th17-immune response, LAP-dependent mechanism of killing and were fully protected from invasive fungal infection. Together, these results identify exuberant viral induced IFN-γ production as a major driver of immune dysfunction in IAPA, paving the way to explore the use of excessive viral-induced IFN-γ as a biomarker and new immunotherapeutic target in IAPA. This research was funded by the Research Foundation Flanders (FWO), project funding under Grant G053121N to JW, SHB and GVV; G057721N, G0G4820N to GVV; 1506114N to KL and GVV; KU Leuven internal funds (C24/17/061) to GVV, clinical research funding to JW, Research Foundation Flanders (FWO) aspirant mandate under Grant 1186121N/1186123N to LS, 11B5520N to FS, 1SF2222N to EV and 11M6922N/11M6924N to SF, travel grants V428023N, K103723N, K217722N to LS. FLvdV was supported by a Vidi grant of the Netherlands Association for Scientific Research. FLvdV, JW, AC and GC were supported by the Europeans Union's Horizon 2020 research and innovation program under grant agreement no 847507 HDM-FUN. AC was also supported by the Fundação para a Ciência e a Tecnologia (FCT), with the references UIDB/50026/2020, UIDP/50026/2020, PTDC/MED-OUT/1112/2021 (https://doi.org/10.54499/PTDC/MED-OUT/1112/2021), and 2022.06674.PTDC (http://doi.org/10.54499/2022.06674.PTDC); and the "la Caixa" Foundation under the agreement LCF/PR/HR22/52420003 (MICROFUN).

Low protein diet protects the liver from Salmonella Typhimurium-mediated injury by modulating the mTOR/autophagy axis in macrophages

Western diets are the underlying cause of metabolic and liver diseases. Recent trend to limit the consumption of protein-rich animal products has become more prominent. This dietary change entails decreased protein consumption; however, it is still unknown how this affects innate immunity. Here, we studied the influence of a low protein diet (LPD) on the liver response to bacterial infection in mice. We found that LPD protects from Salmonella enterica serovar Typhimurium (S. Typhimurium)-induced liver damage. Bulk and single-cell RNA sequencing of murine liver cells showed reduced inflammation and upregulation of autophagy-related genes in myeloid cells in mice fed with LPD after S. Typhimurium infection. Mechanistically, we found reduced activation of the mammalian target of rapamycin (mTOR) pathway, whilst increased phagocytosis and activation of autophagy in LPD-programmed macrophages. We confirmed these observations in phagocytosis and mTOR activation in metabolically programmed human peripheral blood monocyte-derived macrophages. Together, our results support the causal role of dietary components on the fitness of the immune system.

Immunogram dynamics of students under the influence of dosed physical activity

Analysis of the dynamics of the state of blood leukocytes in muscular activity is relevant due to the development of methods of differentiation and assessment of the state of these cells. The purpose of the study is to study the dynamics of the phagocytic and NBT activity of neutrophils, as well as the content of CD lymphocytes of peripheral blood in students when moving on a treadmill. For students 18-20 years old involved in athletics (3 boys and 4 girls), blood was taken from the ulnar vein before and after a 15-minute jog, as well as after a 15-minute run of moderate intensity. The average level of physical performance of the examined PWC170 was 16.25±2.21 kGm/min/kg. Assessment of phagocytosis and NBT activity of neutrophils and determination of blood CD lymphocytes by immunophenotyping were performed using flow cytometry. It was found that in girls at rest, the relative content of lymphocytes and NK cells was significantly lower, and the level of induced NBT activity of neutrophils and the relative content of CD4-CD8- and CD4+CD8+ lymphocytes was significantly higher than in boys. At the same time, the dynamics of the leukogram parameters examined during the dosed physical activity fully corresponded to the development of the lymphocytic phase of myogenic leukocytosis. With an increase in the power of repeated exercise against the background of a general increase in the number of phagocytic neutrophils, the balance of spontaneous NBT-positive and reserve potentially active neutrophils significantly increased relative to the content of NBT-negative cells in the induced test. At the same time, the level of neutrocytes in girls was significantly higher, causing a higher level of phagocyte count and absolute content of NBT-positive neutrophils in a spontaneous and induced test. At the same time, against the background of an increase in the absolute content of CD4-CD8- and TNK lymphocytes, a statistically significant increase in the relative and absolute content of NK cells was observed. In contrast to the boys after the 2nd physical exercise, the relative and absolute content of NK cells, as well as the increase in the percentage of HBT-positive cells in the induced test, were significantly higher.

Extraction and functional characterization of fucoidans and alginates from Ecklonia maxima: A focus on skin, immune, and intestinal health

Polysaccharides from the brown seaweed Ecklonia maxima (EM), were structurally characterized using high performance size exclusion chromatography (HPSEC), Fourier-transform infrared spectroscopy (FTIR) and proton nuclear magnetic resonance (1H NMR) spectroscopy, and assessed for immunomodulation. MTT and AlamarBlue assays evaluated their effects on cell viability and proliferation (skin cells; HDF, HaCaT). Nitric oxide (NO) production and phagocytosis activities were evaluated using RAW264.7 cells. In addition, Caco-2 cells were exposed to EM polysaccharides, including fucoidans and alginates, with the aim of evaluating their potential toxicity towards intestinal cells. The expression levels of tumor necrosis factor alpha (TNF-α) and transforming growth factor beta (TGF-β1) were measured by qPCR at 24 h after treatment with fucoidans (EM-1A, EM-1B, EM-2B, EM-3B) and alginates (EM-2A, EM-3A) polysaccharide fractions, demonstrating that EM-2A and 3A effectively inhibited inflammation, while EM-2B increased wound healing in HaCaT. Skin cell proliferation and migration were significantly increased (0.13 μg/μL), while exposure of RAW264.7 cells to cold or hot-extracted (2A, 2B) polysaccharides did not affect cell proliferation within 24 h. Cell proliferation in Caco-2 cells were significantly reduced by EM-1A fraction at 72 h, inhibiting cell proliferation (p < 0.001). Phagocytosis activity was significantly higher in EM-2B (122.3 ± 1.2%, p < 0.0001), suggesting pro-inflammatory potential. HDF cell proliferation was higher in EM-3A, whereas SOD activity was lower than controls (LPS: 27.3 ± 1.3%). Fucoidan from fraction 2B fraction accelerated skin cell proliferation and migration, showing their potential as bioactive compounds. The findings suggest that EM fucoidan and alginate polysaccharides would be useful for the development of products for food, pharmaceutical and biotechnology applications.

SIRT7 remodels the cytoskeleton via RAC1 to enhance host resistance to Mycobacterium tuberculosis.

Phagocytosis of Mycobacterium tuberculosis (Mtb) followed by its integration into the matured lysosome is critical in the host defense against tuberculosis. How Mtb escapes this immune attack remains elusive. In this study, we unveiled a novel regulatory mechanism by which SIRT7 regulates cytoskeletal remodeling by modulating RAC1 activation. We discovered that SIRT7 expression was significantly reduced in CD14+ monocytes of TB patients. Mtb infection diminished SIRT7 expression by macrophages at both the mRNA and protein levels. SIRT7 deficiency impaired actin cytoskeleton-dependent macrophage phagocytosis, LC3II expression, and bactericidal activity. In a murine tuberculosis model, SIRT7 deficiency detrimentally impacted host resistance to Mtb, while Sirt7 overexpression significantly increased the host defense against Mtb, as determined by bacterial burden and inflammatory-histopathological damage in the lung. Mechanistically, we demonstrated that SIRT7 limits Mtb infection by directly interacting with and activating RAC1, through which cytoskeletal remodeling is modulated. Therefore, we concluded that SIRT7, in its role regulating cytoskeletal remodeling through RAC1, is critical for host responses during Mtb infection and proposes a potential target for tuberculosis treatment.IMPORTANCETuberculosis (TB), caused by Mycobacterium tuberculosis (Mtb), remains a significant global health issue. Critical to macrophages' defense against Mtb is phagocytosis, governed by the actin cytoskeleton. Previous research has revealed that Mtb manipulates and disrupts the host's actin network, though the specific mechanisms have been elusive. Our study identifies a pivotal role for SIRT7 in this context: Mtb infection leads to reduced SIRT7 expression, which, in turn, diminishes RAC1 activation and consequently impairs actin-dependent phagocytosis. The significance of our research is that SIRT7 directly engages with and activates Rac Family Small GTPase 1 (RAC1), thus promoting effective phagocytosis and the elimination of Mtb. This insight into the dynamic between host and pathogen in TB not only broadens our understanding but also opens new avenues for therapeutic development.

A Hirsutella sinensis Alcohol Extract Exerts Bidirectional Immunoregulatory Effects by Regulating Macrophage Polarization.

For background, Hirsutella sinensis, the only anamorphic fungus considered an effective substitute for Cordyceps sinensis, possesses immunoregulatory properties. However, the specific mechanism underlying the immunoregulatory function of Hirsutella sinensis remains unclear. The purpose is to investigate the therapeutic effects of Hirsutella sinensis alcohol extract (HSAE) on immune dysregulation and elucidate the underlying mechanisms involved. For methods, we established inflammatory and immunosuppression models in vitro and in vivo to evaluate the bidirectional immunoregulatory function of HSAE via qRT-PCR and immunoblotting. We also studied its potential mechanism via RNA sequencing and transcriptional analysis. We further established M1 and M2 cell models to explore the effect of HSAE on M1/M2 polarization using qRT-PCR, immunoblotting, and flow cytometry. For results, our data demonstrated enhanced proliferation, phagocytosis, and antipathogenic activities of macrophages. Treatment with HSAE led to increases in the proportions of CD3+ and CD4+ immune cells in cyclophosphamide-induced immunosuppressed mice. Additionally, HSAE reduced the lipopolysaccharide (LPS)-induced expression of Il1b, Il6, Ifnb1, and Cxcl10 by inhibiting the activation of the NF-κB and MAPK pathways in vitro and improved mouse survival by reducing the proportion of M1/M2 macrophages in septic mice. Finally, we found that HSAE inhibited M1 polarization by decreasing the expression of iNOS and CD86 and promoted M2 polarization by increasing the expression of ARG1 and CD206. For conclusions, our study provides evidence that HSAE has the potential to enhance immune responses and suppress excessive inflammation. These effects were realized by modulating macrophage polarization, providing novel insights into the fundamental mechanism underlying the bidirectional immunomodulatory effect of HSAE.

Potential of Graptophyllum pictum Leaf Decoction as an Immunomodulator: Modulation of Macrophage Phagocytosis and Lymphocyte Proliferation

Background: Red pudding leaves (Graptophyllum pictum) are commonly used by the Lebong community in Bengkulu as an immune system-enhancing drink containing flavonoids, glycosides, saponins, tannins, and triterpenoids. Objective: This study aimed to evaluate the potential of red pudding leaves as immunomodulatory agents in vitro and assess their total flavonoid content. Methods: The extraction method employed was a decoction, and the flavonoid content was measured using the TLC method by calculating the resulting Rf value and utilizing the LC-MS technique. The total flavonoid content was quantified using a colorimetric method, and immunomodulatory activity was assessed based on the phagocytosis capacity, phagocytosis index, and lymphocyte proliferation. Results: The results showed that red pudding leaf contained flavonoid compounds based on the LC-MS method in the form of trans-3-Indoleacrylic acid, schaftoside, adenine, corymboside, fraxetin and 4-coumaric acid. The total flavonoid content obtained at a concentration of 7.5% amounted to 74.937 mg QE/g; at a concentration of 15%, it amounted to 75.483 mg QE/g; and at a concentration of 30%, it amounted to 97.825 mg QE/g. All red pudding leaf infusion concentrations increased macrophage phagocytosis activity and lymphocyte cell proliferation. Conclusion: In conclusion, red pudding leaves show potential for development as an alternative beverage to enhance the immune system.

Galectins induced from hemocytes bridge phosphatidylserine and N-glycosylated Drpr/CED-1 receptor during dendrite pruning

During neuronal pruning, phagocytes engulf shed cellular debris to avoid inflammation and maintain tissue homeostasis. How phagocytic receptors recognize degenerating neurites had been unclear. Here, we identify two glucosyltransferases Alg8 and Alg10 of the N-glycosylation pathway required for dendrite fragmentation and clearance through genetic screen. The scavenger receptor Draper (Drpr) is N-glycosylated with complex- or hybrid-type N-glycans that interact specifically with galectins. We also identify the galectins Crouching tiger (Ctg) and Hidden dragon (Hdg) that interact with N-glycosylated Drpr and function in dendrite pruning via the Drpr pathway. Ctg and Hdg are required in hemocytes for expression and function, and are induced during dendrite injury to localize to injured dendrites through specific interaction with exposed phosphatidylserine (PS) on the surface membrane of injured dendrites. Thus, the galectins Ctg and Hdg bridge the interaction between PS and N-glycosylated Drpr, leading to the activation of phagocytosis.

IOS-1002, a Stabilized HLA-B57 Open Format, Exerts Potent Anti-Tumor Activity.

HLA-B27 and HLA-B57 are associated with autoimmunity and long-term viral control and protection against HIV and HCV infection; however, their role in cancer immunity remains unknown. HLA class I molecules interact with innate checkpoint receptors of the LILRA, LILRB and KIR families present in diverse sets of immune cells. Here, we demonstrate that an open format (peptide free conformation) and expression- and stability-optimized HLA-B57-B2m-IgG4_Fc fusion protein (IOS-1002) binds to human leukocyte immunoglobulin-like receptor B1 and B2 (LILRB1 and LILRB2) and to killer immunoglobulin-like receptor 3DL1 (KIR3DL1). In addition, we show that the IgG4 Fc backbone is required for engagement to Fcγ receptors and potent activation of macrophage phagocytosis. IOS-1002 blocks the immunosuppressive ITIM and SHP1/2 phosphatase signaling cascade, reduces the expression of immunosuppressive M2-like polarization markers of macrophages and differentiation of monocytes to myeloid-derived suppressor cells, enhances tumor cell phagocytosis in vitro and potentiates activation of T and NK cells. Lastly, IOS-1002 demonstrates efficacy in an ex vivo patient-derived tumor sample tumoroid model. IOS-1002 is a first-in-class multi-target and multi-functional human-derived HLA molecule that activates anti-tumor immunity and is currently under clinical evaluation.