Macrophage Function Research Articles

Effects of ON101 for Hard-to-Heal Diabetic Foot Ulcers in a Randomized Phase III Trial: A Post Hoc Analysis.

Objective: Hard-to-heal diabetic foot ulcers (DFUs) are associated with higher mortality rates and an increased medical burden for patients. ON101, a new topical cream, exhibited better healing efficacy than the control dressing in a Phase III trial. In this post hoc analysis, we further identify whether ON101 can improve the healing of ulcers with hard-to-heal risk factors in this cohort of DFU patients. Approach: To compare the efficacy of ON101 with absorbent dressing among various hard-to-heal wounds in patients with DFU, a post hoc analysis of a randomized Phase III trial that included 276 DFU patients was performed by subgrouping those patients based on ulcer depth, location, size, duration, and patients' glycated hemoglobin (HbA1c) levels and body mass index (BMI). Results: In the full analysis set, the proportion of patients achieving healing was 61.7% in the ON101 group and 37.0% in the comparator (p = 0.0001). In subgroup analysis according to risk factors, ON101 demonstrated superior healing capacity on Wagner grade 2 ulcers (p < 0.0001); plantar ulcers (p = 0.0016), ulcer size ≥5 cm2 (p = 0.0122), ulcer duration ≥3 months (p = 0.0043); for patients with HbA1c ≥9% (p = 0.0285); and patients with BMI ≥25 (p = 0.0005). Innovation: ON101, a novel therapeutic drug, can modulate the functions of macrophages and demonstrate superior healing rates to conventional absorbent dressing in patients with hard-to-heal DFUs. Conclusions: The results of this post hoc study suggest that ON101 is a better therapeutic option than conventional dressing used in treatment for DFU patients with higher HbA1c, BMI, or ulcers with complex conditions such as longer duration, deeper wounds, larger size, and plantar location.

Immunomodulation by glucocorticoid-induced leucine zipper in macrophages: enhanced phagocytosis, protection from pyroptosis, and altered mitochondrial function.

Glucocorticoids, which have long served as fundamental therapeutics for diverse inflammatory conditions, are still widely used, despite associated side effects limiting their long-term use. Among their key mediators is glucocorticoid-induced leucine zipper (GILZ), recognized for its anti-inflammatory and immunosuppressive properties. Here, we explore the immunomodulatory effects of GILZ in macrophages through transcriptomic analysis and functional assays. Bulk RNA sequencing of GILZ knockout and GILZ-overexpressing macrophages revealed significant alterations in gene expression profiles, particularly impacting pathways associated with the inflammatory response, phagocytosis, cell death, mitochondrial function, and extracellular structure organization activity. GILZ-overexpression enhances phagocytic and antibacterial activity against Salmonella typhimurium and Escherichia coli, potentially mediated by increased nitric oxide production. In addition, GILZ protects macrophages from pyroptotic cell death, as indicated by a reduced production of reactive oxygen species (ROS) in GILZ transgenic macrophages. In contrast, GILZ KO macrophages produced more ROS, suggesting a regulatory role of GILZ in ROS-dependent pathways. Additionally, GILZ overexpression leads to decreased mitochondrial respiration and heightened matrix metalloproteinase activity, suggesting its involvement in tissue remodeling processes. These findings underscore the multifaceted role of GILZ in modulating macrophage functions and its potential as a therapeutic target for inflammatory disorders, offering insights into the development of novel therapeutic strategies aimed at optimizing the benefits of glucocorticoid therapy while minimizing adverse effects.

CLEC7A regulates M2 macrophages to suppress the immune microenvironment and implies poorer prognosis of glioma.

Gliomas constitute a category of malignant tumors originating from brain tissue, representing the majority of intracranial malignancies. Previous research has demonstrated the pivotal role of CLEC7A in the progression of various cancers, yet its specific implications within gliomas remain elusive. The primary objective of this study was to investigate the prognostic significance and immune therapeutic potential of CLEC7A in gliomas through the integration of bioinformatics and clinical pathological analyses. This investigation involved examining and validating the relationship between CLEC7A and glioma using samples from Hospital, along with data from TCGA, GEO, GTEx, and CGGA datasets. Subsequently, we explored its prognostic value, biological functions, expression location, and impact on immune cells within gliomas. Finally, we investigated its potential impact on the chemotaxis and polarization of macrophages. The expression of CLEC7A is upregulated in gliomas, and its levels escalate with the malignancy of tumors, establishing it as an independent prognostic factor. Functional enrichment analysis revealed a significant correlation between CLEC7A and immune function. Subsequent examination of immune cell differential expression demonstrated a robust association between CLEC7A and M2 macrophages. This conclusion was further substantiated through single-cell analysis, immunofluorescence, and correlation studies. Finally, the knockout of CLEC7A in M2 macrophages resulted in a noteworthy reduction in macrophage chemotaxis and polarization factors. CLEC7A expression is intricately linked to the pathology and molecular characteristics of gliomas, establishing its role as an independent prognostic factor for gliomas and influencing macrophage function. It could be a promising target for immunotherapy in gliomas.

Macrophage Polarization and Functions in Pathogenesis of Chronic Obstructive Pulmonary Disease.

Chronic obstructive pulmonary disease (COPD), the major leading cause of mortality worldwide, is a progressive and irreversible respiratory condition characterized by peripheral airway and lung parenchymal inflammation, accompanied by fibrosis, emphysema, and airflow limitation, and has multiple etiologies, including genetic variance, air pollution, and repetitive exposure to harmful substances. However, the precise mechanisms underlying the pathogenesis of COPD have not been identified. Recent multiomics-based evidence suggests that the plasticity of alveolar macrophages contributes to the onset and progression of COPD through the coordinated modulation of numerous transcription factors. Therefore, this review focuses on understanding the mechanisms and functions of macrophage polarization that regulate lung homeostasis in COPD. These findings may provide a better insight into the distinct role of macrophages in COPD pathogenesis and perspective for developing novel therapeutic strategies targeting macrophage polarization.

Lactate and lactylation in macrophage metabolic reprogramming: current progress and outstanding issues.

It is commonly known that different macrophage phenotypes play specific roles in different pathophysiological processes. In recent years, many studies have linked the phenotypes of macrophages to their characteristics in different metabolic pathways, suggesting that macrophages can perform different functions through metabolic reprogramming. It is now gradually recognized that lactate, previously overlooked as a byproduct of glycolytic metabolism, acts as a signaling molecule in regulating multiple biological processes, including immunological responses and metabolism. Recently, lactate has been found to mediate epigenetic changes in macrophages through a newfound lactylation modification, thereby regulating their phenotypic transformation. This novel finding highlights the significant role of lactate metabolism in macrophage function. In this review, we summarize the features of relevant metabolic reprogramming in macrophages and the role of lactate metabolism therein. We also review the progress of research on the regulation of macrophage metabolic reprogramming by lactylation through epigenetic mechanisms.

Sr-Incorporated Bioactive Glass Remodels the Immunological Microenvironment by Enhancing the Mitochondrial Function of Macrophage via the PI3K/AKT/mTOR Signaling Pathway.

The repair of critical-sized bone defects continues to pose a challenge in clinics. Strontium (Sr), recognized for its function in bone metabolism regulation, has shown potential in bone repair. However, the underlying mechanism through which Sr2+ guided favorable osteogenesis by modulating macrophages remains unclear, limiting their application in the design of bone biomaterials. Herein, Sr-incorporated bioactive glass (SrBG) was synthesized for further investigation. The release of Sr ions enhanced the immunomodulatory properties and osteogenic potential by modulating the polarization of macrophages toward the M2 phenotype. In vivo, a 3D-printed SrBG scaffold was fabricated and showed consistently improved bone regeneration by creating a prohealing immunological microenvironment. RNA sequencing was performed to explore the underlying mechanisms. It was found that Sr ions might enhance the mitochondrial function of macrophage by activating PI3K/AKT/mTOR signaling, thereby favoring osteogenesis. Our findings demonstrate the relationship between the immunomodulatory role of Sr ions and the mitochondrial function of macrophages. By focusing on the mitochondrial function of macrophages, Sr2+-mediated immunomodulation sheds light on the future design of biomaterials for tissue regenerative engineering.

Extracellular vesicles of Bacteroides uniformis induce M1 macrophage polarization and aggravate gut inflammation during weaning

Weaning process is commonly associated with gastrointestinal inflammation and dysbiosis of the intestinal microbes. In particular, the impact of gut bacteria and of extracellular vesicles (EV) on the etiology of intestinal inflammation during weaning is not well understand. We have uncovered a potential link between gut inflammation and the corresponding variation of macrophage bacterial sensing and pro-inflammatory polarization during the weaning process of piglet through single-cell transcriptomic analyses. We conducted a comprehensive analysis of bacterial distribution across the gastrointestinal tract and pinpointed Bacteroides uniformis (B. uniformis) enriching in piglets undergoing weaning. Next, we found out that exposure to B. uniformis-derived EVs (BEVs) exacerbated gut inflammation in a murine colitis model while recruiting and polarizing intestinal macrophages towards a pro-inflammatory phenotype. BEVs modulated the function of macrophages cultured in vitro by suppressing the GM-CSF/STAT5/ARG1 pathway, thereby affecting polarization towards an M1-like state. The effects of BEVs were verified both in the macrophage-clearance murine model and by using an adoptive transfer assay. Our findings highlight the involvement of BEVs in facilitating the polarization of pro-inflammatory macrophages and promoting gut inflammation during weaning.

Lactococcus lactis subsp. cremoris C60 Upregulates Macrophage Function by Modifying Metabolic Preference in Enhanced Anti-Tumor Immunity

Lactococcus lactis subsp. cremoris C60 is a probiotic strain of lactic acid bacteria (LAB) which induces various immune modifications in myeloid lineage cells. These modifications subsequently regulate T cell function, resulting in enhanced immunity both locally and systemically. Here, we report that C60 suppresses tumor growth by enhancing macrophage function via metabolic alterations, thereby increasing adenosine triphosphate (ATP) production in a murine melanoma model. Intragastric (i.g.) administration of C60 significantly reduced tumor volume compared to saline administration in mice. The anti-tumor function of intratumor (IT) macrophage was upregulated in mice administered with C60, as evidenced by an increased inflammatory phenotype (M1) rather than an anti-inflammatory/reparative (M2) phenotype, along with enhanced antigen-presenting ability, resulting in increased tumor antigen-specific CD8+ T cells. Through this functional modification, we identified that C60 establishes a glycolysis-dominant metabolism, rather than fatty acid oxidation (FAO), in IT macrophages, leading to increased intracellular ATP levels. To address the question of why orally supplemented C60 exhibits functions in distal places, we found a possibility that bacterial cell wall components, which could be distributed throughout the body from the gut, may induce stimulatory signals in peripheral macrophages via Toll-like receptors (TLRs) signaling activation. Thus, C60 strengthens macrophage anti-tumor immunity by promoting a predominant metabolic shift towards glycolysis upon TLR-mediated stimulation, thereby increasing substantial energy production.

A mouse model of wildfire smoke-induced health effects: sex differences in acute and sustained effects of inhalation exposures

Due to climate change, wildfires have increased in intensity and duration. While wildfires threaten lives directly, the smoke has more far-reaching adverse health impacts. During an extreme 2017 wildfire event, residents of Seeley Lake, Montana were exposed to unusually high levels of wood smoke (WS) causing sustained effects on lung function (decreased FEV1/FVC). Objective: The present study utilized an animal model of WS exposure to research cellular and molecular mechanisms of the resulting health effects. Methods: Mice were exposed to inhaled WS utilizing locally harvested wood to recapitulate community exposures. WS was generated at a rate resulting in a 5 mg/m3 PM2.5 exposure for five days. Results: This exposure resulted in a similar 0.28 mg/m2 particle deposition (lung surface area) in mice that was calculated for human exposure. As with the community observations, there was a significant effect on lung function, increased resistance, and decreased compliance, that was more pronounced in males at an extended (2 months) timepoint and males were more affected than females: ex vivo assays illustrated changes to alveolar macrophage functions (increased TNFα secretion and decreased efferocytosis). Female mice had significantly elevated IL-33 levels in lungs, however, pretreatment of male mice with IL-33 resulted in an abrogation of the observed WS effects, suggesting a dose-dependent role of IL-33. Additionally, there were greater immunotoxic effects in male mice. Discussion: These findings replicated the outcomes in humans and suggest that IL-33 is involved in a mechanism of the adverse effects of WS exposures that inform on potential sex differences.

O14 Monocytes and macrophages in the melanoma tumour microenvironment express Fc receptors which can be engaged with monoclonal antibodies of different isotypes

Abstract Introduction and aims Melanoma is the deadliest form of skin cancer and has an increasing worldwide incidence. It is well established that the melanoma tumour microenvironment (TME) has a large immune cell infiltrate, including a prominent monocytic compartment. Monocytic cells within the TME support melanoma growth, survival and metastasis. Contrastingly, such cells can be stimulated to promote tumour killing when engaged with monoclonal antibodies (mAbs) against cancer antigens, owing to their expression of multiple Fc receptors (FcRs). However, little is known about the monocytic subsets present within melanoma, the FcRs they express and how engaging their FcRs may influence function. Methods Flow cytometry on peripheral monocytes isolated from patients with melanoma and healthy volunteers enabled the characterization of cell surface markers. Next, publicly available single-cell RNA-Seq datasets were analysed to explore the transcriptome of melanoma-associated macrophages and these phenotypes were recapitulated in vitro. Finally, monocytes and macrophages were cocultured with melanoma cells, with or without the addition of mAbs against a melanoma antigen, in order to assess the effect of FcR crosslinking on monocyte and macrophage phenotype and function. Results Circulating monocytes in patients with melanoma feature an inhibitory phenotype, and express multiple FcRs, including Fcε and Fcγ receptors, which could be targeted with mAbs of multiple isotypes. Secondly, monocytic cells within the melanoma TME express protumour genes, including metalloproteinases and angiogenic factors. However, FcR expression suggests that tumour-promoting subsets can be targeted with mAbs. Finally, in ex vivo cocultures with melanoma cells, the FcRs of both human monocytes and macrophages are able to engage antimelanoma mAbs of multiple isotypes, inducing differential phenotype change. This is demonstrated by the upregulation of activation markers and costimulatory cell surface markers. Conclusions Together, these data suggest that tumour-promoting monocytic cells within the melanoma TME can be engaged and harnessed using different isotypes of mAbs targeting melanoma.

Biomechanics of Macrophages on Disordered Surface Nanotopography.

Macrophages are involved in every stage of the innate/inflammatory immune responses in the body tissues, including the resolution of the reaction, and they do so in close collaboration with the extracellular matrix (ECM). Simplified substrates with nanotopographical features attempt to mimic the structural properties of the ECM to clarify the functional features of the interaction of the ECM with macrophages. We still have a limited understanding of the macrophage behavior upon interaction with disordered nanotopography, especially with features smaller than 10 nm. Here, we combine atomic force microscopy (AFM), finite element modeling (FEM), and quantitative biochemical approaches in order to understand the mechanotransduction from the nanostructured surface into cellular responses. AFM experiments show a decrease of macrophage stiffness, measured with the Young's modulus, as a biomechanical response to a nanostructured (ns-) ZrOx surface. FEM experiments suggest that ZrOx surfaces with increasing roughness represent weaker mechanical boundary conditions. The mechanical cues from the substrate are transduced into the cell through the formation of integrin-regulated focal adhesions and cytoskeletal reorganization, which, in turn, modulate cell biomechanics by downregulating cell stiffness. Surface nanotopography and consequent biomechanical response impact the overall behavior of macrophages by increasing movement and phagocytic ability without significantly influencing their inflammatory behavior. Our study suggests a strong potential of surface nanotopography for the regulation of macrophage functions, which implies a prospective application relative to coating technology for biomedical devices.

The immune suppressive functions of macrophages are impaired in patients with ulcerative colitis

Chronic inflammation is the pathological feature of inflammatory bowel diseases (IBD), but its etiology is unknown. Macrophages are one of the major immune cell fractions in the colon. The objectives of this study are to characterize the immune regulatory functions of macrophages in the colon of patients with ulcerative colitis (UC). UC patients (n = 30) were recruited into this study. Colon lavage fluid (CLF) was collected. Macrophages are isolated from the cellular components of CLF. The immune suppressive functions of macrophages were assessed using immunological approaches. We observed that macrophages occupied about half of the proportions of the cellular components in CLF. Lower amounts of IL10 mRNA and proteins were detected in macrophages of the UC group than the normal control (NC) group. The expression of IL10 in CLF macrophages was positively correlated with the UC-associated cytokines, including tumor necrosis factor-α, interleukin (IL)-1β, IFN-γ, eosinophil-derived mediators, in CLF. The immune suppressive functions of CLF macrophages in UC patients were impaired. The inducibility of IL10 expression of UC M0 cells was defective as compared with NC M0 cells. Exposure to CpG restored the inducibility of IL10 expression in UC M0 cells, and gain the potential to acquire the immune suppressive functions. To sum up, the immune suppressive functions of UC macrophages are impaired. The inducibility of IL10 expression of M0 cells is impaired, which can be restored by the treatment with CpG.

GITR exacerbates lysophosphatidylcholine-induced macrophage pyroptosis in sepsis via posttranslational regulation of NLRP3.

The NLRP3 inflammasome functions as an inflammatory driver, but its relationship with lipid metabolic changes in early sepsis remains unclear. Here, we found that GITR expression in monocytes/macrophages was induced by lysophosphatidylcholine (LPC) and was positively correlated with the severity of sepsis. GITR is a costimulatory molecule that is mainly expressed on T cells, but its function in macrophages is largely unknown. Our in vitro data showed that GITR enhanced LPC uptake by macrophages and specifically enhanced NLRP3 inflammasome-mediated macrophage pyroptosis. Furthermore, in vivo studies using either cecal ligation and puncture (CLP) or LPS-induced sepsis models demonstrated that LPC exacerbated sepsis severity/lethality, while conditional knockout of GITR in myeloid cells or NLRP3/caspase-1/IL-1β deficiency attenuated sepsis severity/lethality. Mechanistically, GITR specifically enhanced inflammasome activation by regulating the posttranslational modification (PTM) of NLRP3. GITR competes with NLRP3 for binding to the E3 ligase MARCH7 and recruits MARCH7 to induce deacetylase SIRT2 degradation, leading to decreasing ubiquitination but increasing acetylation of NLRP3. Overall, these findings revealed a novel role of macrophage-derived GITR in regulating the PTM of NLRP3 and systemic inflammatory injury, suggesting that GITR may be a potential therapeutic target for sepsis and other inflammatory diseases. GITR exacerbates LPC-induced macrophage pyroptosis in sepsis via posttranslational regulation of NLRP3. According to the model, LPC levels increase during the early stage of sepsis, inducing GITR expression on macrophages. GITR not only competes with NLRP3 for binding to the E3 ligase MARCH7 but also recruits MARCH7 to induce the degradation of the deacetylase SIRT2, leading to decreasing ubiquitination but increasing acetylation of NLRP3 and therefore exacerbating LPC-induced NLRP3 inflammasome activation, macrophage pyroptosis and systemic inflammatory injury.

Macrophage Functions in Psoriasis: Lessons from Mouse Models.

Psoriasis is a systemic autoimmune/autoinflammatory disease that can be well studied in established mouse models. Skin-resident macrophages are classified into epidermal Langerhans cells and dermal macrophages and are involved in innate immunity, orchestration of adaptive immunity, and maintenance of tissue homeostasis due to their ability to constantly shift their phenotype and adapt to the current microenvironment. Consequently, both macrophage populations play dual roles in psoriasis. In some circumstances, pro-inflammatory activated macrophages and Langerhans cells trigger psoriatic inflammation, while in other cases their anti-inflammatory stimulation results in amelioration of the disease. These features make macrophages interesting candidates for modern therapeutic strategies. Owing to the significant progress in knowledge, our review article summarizes current achievements and indicates future research directions to better understand the function of macrophages in psoriasis.

Biodegradable Zn-2Cu-0.5Zr alloy promotes the bone repair of senile osteoporotic fractures via the immune-modulation of macrophages

Delayed bone-healing of senile osteoporotic fractures remains a clinical challenge due to the alterations caused by aging in bone and immune systems. The novel biomaterials that address the deficiencies in both skeletal cells and immune systems are required to effectively treat the bone injuries of older patients. Zinc (Zn) has shown promise as a biodegradable material for use in orthopedic implants. To address the bone-healing deficiencies in elderly patients with bone injuries, we developed a biodegradable Zn-based alloy (Zn–2Cu-0.5Zr) with enhanced mechanical properties, including a yield strength of 198.7 MPa and ultimate tensile strength of 217.6 MPa, surpassing those of pure Zn and Zn–2Cu alloys. Cytotoxicity tests conducted on bone marrow mesenchymal stem cells (BMSCs) and MC3T3-E1 cells demonstrated that the extracts from Zn–2Cu-0.5Zr alloy exhibited no observable cytotoxic effects. Furthermore, the extracts of Zn–2Cu-0.5Zr alloy exhibited significant anti-inflammatory effects through regulation of inflammation-related cytokine production and modulation of macrophage polarization. The improved immune-osteo microenvironment subsequently contributed to osteogenic differentiation of BMSCs. The potential therapeutic application of Zn–2Cu-0.5Zr in senile osteoporotic fracture was tested using a rat model of age-related osteoporosis. The Zn–2Cu-0.5Zr alloy met the requirements for load-bearing applications and accelerated the healing process in a tibial fracture in aged rats. The imaging and histological analyses showed that it could accelerate the bone-repair process and promote the fracture healing in senile osteoporotic rats. These findings suggest that the novel Zn–2Cu-0.5Zr alloy holds potential for influencing the immunomodulatory function of macrophages and facilitating bone repair in elderly individuals with osteoporosis.

Identification and Verification of Endoplasmic Reticulum Stress-Related Genes as Novel Signatures for Osteoarthritis Diagnosis and Therapy: A Bioinformatics Analysis-Oriented Pilot Study.

Endoplasmic reticulum stress (ERS) has been reported to be closely associated with the development of osteoarthritis (OA), but the underlying mechanisms are not fully delineated. The present study was designed to investigate the involvement of ERS-related genes in regulating OA progression. The expression profiles of OA patients and normal people were downloaded from the gene expression omnibus (GEO) database. The differentially expressed genes (DEGs) in datasets GSE55457 and GSE55235 were screened and identified by R software with the construction of the protein-protein interaction (PPI) networks. Through the STRING and Venn diagram analysis, hub ERS-related genes were obtained. Gene ontology (GO) and kyoto encyclopedia of genes and genomes (KEGG) enrichment analyses were performed. Biomarkers with high diagnostic values of osteoarthritis (OA) were studied. The hematoxylin and eosin (H&E) staining and micro-CT were applied to evaluate the establishment of the OA model. The expression levels of biomarkers were validated with the use of reverse transcription‑quantitative polymerase chain reaction (RT-qPCR) and western blot. Finally, we evaluated the correlations of hub ERS-related genes with the immune infiltration cells via the CIBERSORT algorithm. A total of 60 downregulated and 52 upregulated DEGs were identified, and the following GO and KEGG pathway analyses verified that those DEGs were mainly enriched in biological process (BP), cellular component (CC), molecular function (MF), and inflammation-associated signal pathways. Interestingly, among all the DEGs, six ER stress-associated genes, including activating transcription factor 3 (ATF3), DEAD-Box Helicase 3 X-Linked (DDX3X), AP-1 transcription factor subunit (JUN), eukaryotic initiation factor 4 (EIF4A1), KDEL endoplasmic reticulum protein retention receptor 3 (KDELR3), and vascular endothelial growth factor A (VEGFA), were found to be closely associated with OA progression, and the following RT-qPCR and Western Blot analysis confirmed that DDX3X, JUN, and VEGFA were upregulated, whereas KDELR3, EIF4A1, and ATF3 were downregulated in OA rats tissues compared to the normal tissues, which were in accordance with our bioinformatics findings. Furthermore, our receiver operating characteristic (ROC) curve analysis verified that the above six ER stress-associated genes could be used as ideal biomarkers for OA diagnosis and those genes also potentially regulated immune responses by influencing the biological functions of mast cells and macrophages. Collectively, the present study firstly identified six ER stress-associated genes (ATF3, DDX3X, JUN, EIF4A1, KDELR3, and VEGFA) that may play critical role in regulating the progression of OA.

Retinal microglia express more MHC class I and promote greater T-cell-driven inflammation than brain microglia.

Macrophage function is determined by microenvironment and origin. Brain and retinal microglia are both derived from yolk sac progenitors, yet their microenvironments differ. Utilizing single-cell RNA sequencing (scRNA-seq) data from mice, we tested the hypothesis that retinal and brain microglia exhibit distinct transcriptional profiles due to their unique microenvironments. Eyes and brains from 2-4 month wildtype mice were combined (20 eyes; 3 brains) to yield one biologically diverse sample per organ. Each tissue was digested into single cell suspensions, enriched for immune cells, and sorted for scRNA-seq. Analysis was performed in Seurat v3 including clustering, integration, and differential expression. Multi-parameter flow cytometry was used for validation of scRNA-seq results. Lymphocytic choriomeningitis virus (LCMV) Clone 13, which produces a systemic, chronic, and neurotropic infection, was used to validate scRNA-seq and flow cytometry results in vivo. Cluster analysis of integrated gene expression data from eye and brain identified 6 Tmem119 + P2ry12 + microglial clusters. Differential expression analysis revealed that eye microglia were enriched for more pro-inflammatory processes including antigen processing via MHC class I (14.0-fold, H2-D1 and H2-K1) and positive regulation of T-cell immunity (8.4-fold) compared to brain microglia. Multi-parameter flow cytometry confirmed that retinal microglia expressed 3.2-fold greater H2-Db and 263.3-fold more H2-Kb than brain microglia. On Day 13 and 29 after LCMV infection, CD8+ T-cell density was greater in the retina than the brain. Our data demonstrate that the microenvironment of retina and brain differs, resulting in microglia-specific gene expression changes. Specifically, retinal microglia express greater MHC class I by scRNA-seq and multi-parameter flow cytometry, resulting in a possibly enhanced capability to stimulate CD8+ T-cell inflammation during LCMV infection. These results may explain tissue-specific differences between retina and brain during systemic viral infections and CD8+ T-cell driven autoimmune disease.

Effect of luteolin on glioblastoma's immune microenvironment and tumor growth suppression

BackgroundGlioblastoma is the most malignant and prevalent primary human brain tumor, and the immunological microenvironment controlled by glioma stem cells is one of the essential elements contributing to its malignancy. The use of medications to ameliorate the tumor microenvironment may give a new approach for glioma treatment. MethodsGlioma stem cells were separated from clinical patient-derived glioma samples for molecular research. Other studies, including CCK8, EdU, Transwell, and others, supported luteolin's ability to treat glioma progenitor cells. Network pharmacology and molecular docking models were used to study the drug target, and qRT-PCR, WB, and IF were used to evaluate the molecular mechanism. Intracranial xenografts were examined using HE and IHC, while macrophage polarization was examined using FC. ResultsWe originally discovered that luteolin inhibits glioma stem cells. IL6 released by glioma stem cells is blocked during medication action and inhibits glioma stem cell proliferation and invasion via the IL6/STAT3 signaling pathway. Additionally, luteolin inhibits the secretion of TGFβ1, affects the polarization function of macrophages in the microenvironment, inhibits the polarization of M2 macrophages in TAM, and further inhibits various functions of glioma stem cells by affecting the IL6/STAT3 signaling pathway, luteolin crosstalk TGFβ1/SMAD3 signaling pathway, and so on. ConclusionsThrough the suppression of the immunological microenvironment and inhibition of the IL6/STAT3 signaling pathway, our study determined the inhibitory effect of luteolin on glioma stem cells. This medication's dual inhibitory action, which has a significant negative impact on the glioma stem cells' malignant process, makes it both a viable anti-glioma medication and a candidate for targeted glioma microenvironment therapy.

The effect of macrophages and their exosomes in ischemic heart disease.

Ischemic heart disease (IHD) is a leading cause of disability and death worldwide, with immune regulation playing a crucial role in its pathogenesis. Various immune cells are involved, and as one of the key immune cells residing in the heart, macrophages play an indispensable role in the inflammatory and reparative processes during cardiac ischemia. Exosomes, extracellular vesicles containing lipids, nucleic acids, proteins, and other bioactive molecules, have emerged as important mediators in the regulatory functions of macrophages and hold promise as a novel therapeutic target for IHD. This review summarizes the regulatory mechanisms of different subsets of macrophages and their secreted exosomes during cardiac ischemia over the past five years. It also discusses the current status of clinical research utilizing macrophages and their exosomes, as well as strategies to enhance their therapeutic efficacy through biotechnology. The aim is to provide valuable insights for the treatment of IHD.

Choline metabolism reprogramming mediates an immunosuppressive microenvironment in non-small cell lung cancer (NSCLC) by promoting tumor-associated macrophage functional polarization and endothelial cell proliferation

IntroductionLung cancer is a prevalent malignancy globally, and immunotherapy has revolutionized its treatment. However, resistance to immunotherapy remains a challenge. Abnormal cholinesterase (ChE) activity and choline metabolism are associated with tumor oncogenesis, progression, and poor prognosis in multiple cancers. Yet, the precise mechanism underlying the relationship between ChE, choline metabolism and tumor immune microenvironment in lung cancer, and the response and resistance of immunotherapy still unclear.MethodsFirstly, 277 advanced non-small cell lung cancer (NSCLC) patients receiving first-line immunotherapy in Sun Yat-sen University Cancer Center were enrolled in the study. Pretreatment and the alteration of ChE after 2 courses of immunotherapy and survival outcomes were collected. Kaplan–Meier survival and cox regression analysis were performed, and nomogram was conducted to identify the prognostic and predicted values. Secondly, choline metabolism-related genes were screened using Cox regression, and a prognostic model was constructed. Functional enrichment analysis and immune microenvironment analysis were also conducted. Lastly, to gain further insights into potential mechanisms, single-cell analysis was performed.ResultsFirstly, baseline high level ChE and the elevation of ChE after immunotherapy were significantly associated with better survival outcomes for advanced NSCLC. Constructed nomogram based on the significant variables from the multivariate Cox analysis performed well in discrimination and calibration. Secondly, 4 choline metabolism-related genes (MTHFD1, PDGFB, PIK3R3, CHKB) were screened and developed a risk signature that was found to be related to a poorer prognosis. Further analysis revealed that the choline metabolism-related genes signature was associated with immunosuppressive tumor microenvironment, immune escape and metabolic reprogramming. scRNA-seq showed that MTHFD1 was specifically distributed in tumor-associated macrophages (TAMs), mediating the differentiation and immunosuppressive functions of macrophages, which may potentially impact endothelial cell proliferation and tumor angiogenesis.ConclusionOur study highlights the discovery of ChE as a prognostic marker in advanced NSCLC, suggesting its potential for identifying patients who may benefit from immunotherapy. Additionally, we developed a prognostic signature based on choline metabolism-related genes, revealing the correlation with the immunosuppressive microenvironment and uncovering the role of MTHFD1 in macrophage differentiation and endothelial cell proliferation, providing insights into the intricate workings of choline metabolism in NSCLC pathogenesis.