-
Frontiers in Immunology 2024The interplay between myeloid cells and T-lymphocytes is critical to the regulation of host defense and inflammation resolution. Dysregulation of this interaction can... (Review)
Review
The interplay between myeloid cells and T-lymphocytes is critical to the regulation of host defense and inflammation resolution. Dysregulation of this interaction can contribute to the development of chronic inflammatory diseases. Important among these diseases is atherosclerosis, which refers to focal lesions in the arterial intima driven by elevated apolipoprotein B-containing lipoproteins, notably low-density lipoprotein (LDL), and characterized by the formation of a plaque composed of inflammatory immune cells, a collection of dead cells and lipids called the necrotic core, and a fibrous cap. As the disease progresses, the necrotic core expands, and the fibrous cap becomes thin, which increases the risk of plaque rupture or erosion. Plaque rupture leads to a rapid thrombotic response that can give rise to heart attack, stroke, or sudden death. With marked lowering of circulating LDL, however, plaques become more stable and cardiac risk is lowered-a process known as atherosclerosis regression. A critical aspect of both atherosclerosis progression and regression is the crosstalk between innate (myeloid cells) and adaptive (T-lymphocytes) immune cells. Myeloid cells are specialized at clearing apoptotic cells by a process called efferocytosis, which is necessary for inflammation resolution. In advanced disease, efferocytosis is impaired, leading to secondary necrosis of apoptotic cells, inflammation, and, most importantly, defective tissue resolution. In regression, efferocytosis is reawakened aiding in inflammation resolution and plaque stabilization. Here, we will explore how efferocytosing myeloid cells could affect T-cell function and vice versa through antigen presentation, secreted factors, and cell-cell contacts and how this cellular crosstalk may contribute to the progression or regression of atherosclerosis.
Topics: Humans; Atherosclerosis; T-Lymphocytes; Myeloid Cells; Animals; Cell Communication; Phagocytosis; Apoptosis; Plaque, Atherosclerotic
PubMed: 38873597
DOI: 10.3389/fimmu.2024.1403150 -
European Radiology Experimental Jun 2024New immunotherapies activate tumor-associated macrophages (TAMs) in the osteosarcoma microenvironment. Iron oxide nanoparticles (IONPs) are phagocytosed by TAMs and,...
BACKGROUND
New immunotherapies activate tumor-associated macrophages (TAMs) in the osteosarcoma microenvironment. Iron oxide nanoparticles (IONPs) are phagocytosed by TAMs and, therefore, enable TAM detection on T2*- and T2-weighted magnetic resonance images. We assessed the repeatability and reproducibility of T2*- and T2-mapping of osteosarcomas in a mouse model.
METHODS
Fifteen BALB/c mice bearing-murine osteosarcomas underwent magnetic resonance imaging (MRI) on 3-T and 7-T scanners before and after intravenous IONP infusion, using T2*-weighted multi-gradient-echo, T2-weighted fast spin-echo, and T2-weighted multi-echo sequences. Each sequence was repeated twice. Tumor T2 and T2* relaxation times were measured twice by two independent investigators. Repeatability and reproducibility of measurements were assessed.
RESULTS
We found excellent agreement between duplicate acquisitions for both T2* and T2 measurements at either magnetic field strength, by the same individual (repeatability), and between individuals (reproducibility). The repeatability concordance correlation coefficient (CCC) for T2* values were 0.99 (coefficients of variation (CoV) 4.43%) for reader 1 and 0.98 (CoV 5.82%) for reader 2. The reproducibility of T2* values between the two readers was 0.99 (CoV 3.32%) for the first acquisitions and 0.99 (CoV 6.30%) for the second acquisitions. Regarding T2 values, the repeatability of CCC was similar for both readers, 0.98 (CoV 3.64% for reader 1 and 4.45% for reader 2). The CCC of the reproducibility of T2 was 0.99 (CoV 3.1%) for the first acquisition and 0.98 (CoV 4.38%) for the second acquisition.
CONCLUSIONS
Our results demonstrated high repeatability and reproducibility of quantitative T2* and T2 mapping for monitoring the presence of TAMs in osteosarcomas.
RELEVANCE STATEMENT
T2* and T2 measurements of osteosarcomas on IONP-enhanced MRI could allow identifying patients who may benefit from TAM-modulating immunotherapies and for monitoring treatment response. The technique described here could be also applied across a wide range of other solid tumors.
KEY POINTS
• Optimal integration of TAM-modulating immunotherapies with conventional chemotherapy remains poorly elucidated. • We found high repeatability of T2* and T2 measurements of osteosarcomas in a mouse model, both with and without IONPs contrast, at 3-T and 7-T MRI field strengths. • T2 and T2* mapping may be used to determine response to macrophage-modulating cancer immunotherapies.
Topics: Animals; Osteosarcoma; Mice; Magnetic Resonance Imaging; Reproducibility of Results; Mice, Inbred BALB C; Disease Models, Animal; Bone Neoplasms; Female
PubMed: 38872042
DOI: 10.1186/s41747-024-00467-9 -
Scientific Reports Jun 2024The mechanism by which subarachnoid hemorrhage (SAH) leads to chronic neurologic deficits is unclear. One possibility is that blood activates microglia to drive...
The mechanism by which subarachnoid hemorrhage (SAH) leads to chronic neurologic deficits is unclear. One possibility is that blood activates microglia to drive inflammation that leads to synaptic loss and impaired brain function. Using the endovascular perforation model of SAH in rats, we investigated short-term effects on microglia together with long-term effects on EEG and neurologic function for up to 3 months. Within the first week, microglia were increased both at the site of injury and diffusely across the cortex (2.5-fold increase in SAH compared to controls, p = 0.012). Concomitantly, EEGs from SAH animals showed focal increases in slow wave activity and diffuse reduction in fast activity. When expressed as a fast-slow spectral ratio, there were significant interactions between group and time (p < 0.001) with less ipsilateral recovery over time. EEG changes were most pronounced during the first week and correlated with neurobehavioral impairment. In vitro, the blood product hemin was sufficient to increase microglia phagocytosis nearly six-fold (p = 0.032). Immunomodulatory treatment with fingolimod after SAH reduced microglia, improved neurological function, and increased survival. These findings, which parallel many of the EEG changes seen in patients, suggest that targeting neuroinflammation could reduce long-term neurologic dysfunction following SAH.
Topics: Subarachnoid Hemorrhage; Animals; Microglia; Electroencephalography; Disease Models, Animal; Rats; Male; Phagocytosis; Rats, Sprague-Dawley
PubMed: 38871799
DOI: 10.1038/s41598-024-64631-2 -
Journal of Thrombosis and Haemostasis :... Jun 2024Neutrophils, the most abundant white blood cells in humans, play pivotal roles in innate immunity, rapidly migrating to sites of infection and inflammation to...
BACKGROUND
Neutrophils, the most abundant white blood cells in humans, play pivotal roles in innate immunity, rapidly migrating to sites of infection and inflammation to phagocytose, neutralize, and eliminate invading pathogens. Neutrophil Extracellular Trap (NET) formation is increasingly recognized as an essential rapid innate immune response, but when dysregulated contributes to pathogenesis of sepsis and immunothrombotic disease.
OBJECTIVES
Current NETosis models are limited, routinely employing non-physiological triggers that can bypass natural NET regulatory pathways. Models utilizing isolated neutrophils and immortalized cell lines, do not reflect the complex biology underlying neutrophil activation and NETosis, that occurs in whole-blood. To our knowledge, we report the first human ex-vivo model utilizing naturally occurring molecules to induce NETosis in whole blood. This approach could be used for drug screening and, importantly, inadvertent activators of NETosis.
METHODS
Here we describe a novel, high-throughput ex-vivo whole blood induced NETosis model using combinatorial pooling of native NETosis inducing factors in a more biologically relevant Synthetic-Sepsis™ model.
RESULTS
We found different combinations of factors evoked distinct neutrophil responses in the rate of NET generation and/or magnitude of NETosis. Despite inter-donor variability, similar sets of pro-inflammatory molecules induced consistent responses across donors. We found at least three biological triggers, were necessary to induce NETosis in our system including either TNF-α or LT-α.
CONCLUSION
These findings emphasize the importance of investigating neutrophil physiology in a biologically relevant context to enable a better understanding of disease pathology, risk factors, and therapeutic targets, potentially, providing novel strategies for disease intervention and treatment.
PubMed: 38866247
DOI: 10.1016/j.jtha.2024.05.028 -
IET Nanobiotechnology 2024Diabetic nephropathy (DN) is the leading cause of chronic kidney disease, and the activation and infiltration of phagocytes are critical steps of DN. This study aimed to...
BACKGROUND
Diabetic nephropathy (DN) is the leading cause of chronic kidney disease, and the activation and infiltration of phagocytes are critical steps of DN. This study aimed to explore the mechanism of exosomes in macrophages and diabetes nephropathy and the role of miRNA-34a, which might provide a new path for treating DN.
MATERIALS AND METHODS
The DN model was established, and the success of the model establishment was confirmed by detecting general indicators, HE staining, and immunohistochemistry. Electron microscopy and NanoSight Tracking Analysis (NTA) were used to see the morphology and size of exosomes. MiRNA-34a inhibitor, miRNA-34a mimics, pc-, and controls were transfected in macrophages with or without kidney exosomal. A dual-luciferase reporter gene experiment verifies the targeting relationship between miRNA-34a and . After exosomal culture, macrophages are co-cultured with normal renal tubular cells to detect renal tubular cell fibrosis. Q-PCR and western blot were undertaken to detect related RNA and proteins.
RESULTS
An animal model of diabetic nephropathy was successfully constructed. Macrophages could phagocytose exosomes. After ingesting model exosomes, M1 macrophages were activated, while M2 macrophages were weakened, indicating the model mice's kidney exosomes caused the polarization. MiRNA-34a inhibitor increased expression. MiRNA-34a expressed higher in diabetic nephropathy Model-Exo. MiRNA-34a negatively regulated . rescued macrophage polarization and renal tubular cell fibrosis.
CONCLUSION
Exosomal miRNA-34a of tubular epithelial cells promoted M1 macrophage activation in diabetic nephropathy via negatively regulating expression, which may provide a new direction for further exploration of DN treatment.
Topics: MicroRNAs; Diabetic Nephropathies; Animals; Exosomes; Mice; Macrophages; Fibrosis; Male; Kidney Tubules; Mice, Inbred C57BL; Disease Models, Animal; Diabetes Mellitus, Experimental
PubMed: 38863972
DOI: 10.1049/2024/5702517 -
Frontiers in Immunology 2024Macrophage dysfunction is a common feature of inflammatory disorders such as asthma, which is characterized by a strong circadian rhythm.
INTRODUCTION
Macrophage dysfunction is a common feature of inflammatory disorders such as asthma, which is characterized by a strong circadian rhythm.
METHODS AND RESULTS
We monitored the protein expression pattern of the molecular circadian clock in human peripheral blood monocytes from healthy, allergic, and asthmatic donors during a whole day. Monocytes cultured of these donors allowed us to examine circadian protein expression in human monocyte-derived macrophages, M1- and M2- polarized macrophages. In monocytes, particularly from allergic asthmatics, the oscillating expression of circadian proteins CLOCK, BMAL, REV ERBs, and RORs was significantly altered. Similar changes in BMAL1 were observed in polarized macrophages from allergic donors and in tissue-resident macrophages from activated precision cut lung slices. We confirmed clock modulating, anti-inflammatory, and lung-protective properties of the inverse ROR agonist SR1001 by reduced secretion of macrophage inflammatory protein and increase in phagocytosis. Using a house dust mite model, we verified the therapeutic effect of SR1001 .
DISCUSSION
Overall, our data suggest an interaction between the molecular circadian clock and monocytes/macrophages effector function in inflammatory lung diseases. The use of SR1001 leads to inflammatory resolution and and represents a promising clock-based therapeutic approach for chronic pulmonary diseases such as asthma.
Topics: Humans; Monocytes; Circadian Clocks; Animals; Macrophages; Asthma; Male; Hypersensitivity; Inflammation; Female; Mice; Adult; Pyroglyphidae; Cells, Cultured; Circadian Rhythm
PubMed: 38863703
DOI: 10.3389/fimmu.2024.1408772 -
Journal of Hematology & Oncology Jun 2024Macrophages infiltrating tumour tissues or residing in the microenvironment of solid tumours are known as tumour-associated macrophages (TAMs). These specialized immune... (Review)
Review
Macrophages infiltrating tumour tissues or residing in the microenvironment of solid tumours are known as tumour-associated macrophages (TAMs). These specialized immune cells play crucial roles in tumour growth, angiogenesis, immune regulation, metastasis, and chemoresistance. TAMs encompass various subpopulations, primarily classified into M1 and M2 subtypes based on their differentiation and activities. M1 macrophages, characterized by a pro-inflammatory phenotype, exert anti-tumoural effects, while M2 macrophages, with an anti-inflammatory phenotype, function as protumoural regulators. These highly versatile cells respond to stimuli from tumour cells and other constituents within the tumour microenvironment (TME), such as growth factors, cytokines, chemokines, and enzymes. These stimuli induce their polarization towards one phenotype or another, leading to complex interactions with TME components and influencing both pro-tumour and anti-tumour processes.This review comprehensively and deeply covers the literature on macrophages, their origin and function as well as the intricate interplay between macrophages and the TME, influencing the dual nature of TAMs in promoting both pro- and anti-tumour processes. Moreover, the review delves into the primary pathways implicated in macrophage polarization, examining the diverse stimuli that regulate this process. These stimuli play a crucial role in shaping the phenotype and functions of macrophages. In addition, the advantages and limitations of current macrophage based clinical interventions are reviewed, including enhancing TAM phagocytosis, inducing TAM exhaustion, inhibiting TAM recruitment, and polarizing TAMs towards an M1-like phenotype. In conclusion, while the treatment strategies targeting macrophages in precision medicine show promise, overcoming several obstacles is still necessary to achieve an accessible and efficient immunotherapy.
Topics: Humans; Tumor Microenvironment; Immunotherapy; Neoplasms; Tumor-Associated Macrophages; Precision Medicine; Macrophages; Animals
PubMed: 38863020
DOI: 10.1186/s13045-024-01559-0 -
Nature Communications Jun 2024Cancer-associated fibroblasts (CAFs) have emerged as a dominant non-hematopoietic cell population in the tumour microenvironment, serving diverse functions in tumour...
Cancer-associated fibroblasts (CAFs) have emerged as a dominant non-hematopoietic cell population in the tumour microenvironment, serving diverse functions in tumour progression. However, the mechanisms via which CAFs influence the anti-tumour immunity remain poorly understood. Here, using multiple tumour models and biopsies from cancer patients, we report that α-SMA CAFs can form immunological synapses with Foxp3 regulatory T cells (Tregs) in tumours. Notably, α-SMA CAFs can phagocytose and process tumour antigens and exhibit a tolerogenic phenotype which instructs movement arrest, activation and proliferation in Tregs in an antigen-specific manner. Moreover, α-SMA CAFs display double-membrane structures resembling autophagosomes in their cytoplasm. Single-cell transcriptomic data showed an enrichment in autophagy and antigen processing/presentation pathways in α-SMA-expressing CAF clusters. Conditional knockout of Atg5 in α-SMA CAFs promoted inflammatory re-programming in CAFs, reduced Treg cell infiltration and attenuated tumour development. Overall, our findings reveal an immunosuppressive mechanism entailing the formation of synapses between α-SMA CAFs and Tregs in an autophagy-dependent manner.
Topics: T-Lymphocytes, Regulatory; Cancer-Associated Fibroblasts; Humans; Immunological Synapses; Animals; Tumor Microenvironment; Mice; Autophagy; Actins; Autophagy-Related Protein 5; Neoplasms; Mice, Inbred C57BL; Forkhead Transcription Factors; Female; Mice, Knockout
PubMed: 38862534
DOI: 10.1038/s41467-024-49282-1 -
Signal Transduction and Targeted Therapy Jun 2024Cell membrane-camouflaged nanoparticles possess inherent advantages derived from their membrane structure and surface antigens, including prolonged circulation in the...
Cell membrane-camouflaged nanoparticles possess inherent advantages derived from their membrane structure and surface antigens, including prolonged circulation in the bloodstream, specific cell recognition and targeting capabilities, and potential for immunotherapy. Herein, we introduce a cell membrane biomimetic nanodrug platform termed MPB-3BP@CM NPs. Comprising microporous Prussian blue nanoparticles (MPB NPs) serving as both a photothermal sensitizer and carrier for 3-bromopyruvate (3BP), these nanoparticles are cloaked in a genetically programmable cell membrane displaying variants of signal regulatory protein α (SIRPα) with enhanced affinity to CD47. As a result, MPB-3BP@CM NPs inherit the characteristics of the original cell membrane, exhibiting an extended circulation time in the bloodstream and effectively targeting CD47 on the cytomembrane of colorectal cancer (CRC) cells. Notably, blocking CD47 with MPB-3BP@CM NPs enhances the phagocytosis of CRC cells by macrophages. Additionally, 3BP, an inhibitor of hexokinase II (HK), suppresses glycolysis, leading to a reduction in adenosine triphosphate (ATP) levels and lactate production. Besides, it promotes the polarization of tumor-associated macrophages (TAMs) towards an anti-tumor M1 phenotype. Furthermore, integration with MPB NPs-mediated photothermal therapy (PTT) enhances the therapeutic efficacy against tumors. These advantages make MPB-3BP@CM NPs an attractive platform for the future development of innovative therapeutic approaches for CRC. Concurrently, it introduces a universal approach for engineering disease-tailored cell membranes for tumor therapy.
Topics: Colorectal Neoplasms; Nanoparticles; Humans; CD47 Antigen; Mice; Cell Membrane; Animals; Pyruvates; Hexokinase; Cell Line, Tumor; Macrophages; Ferrocyanides
PubMed: 38862461
DOI: 10.1038/s41392-024-01859-4 -
Investigative Ophthalmology & Visual... Jun 2024N6-methyladenosine (m6A) methylation is a chemical modification that occurs on RNA molecules, where the hydrogen atom of adenine (A) nucleotides is replaced by a methyl...
PURPOSE
N6-methyladenosine (m6A) methylation is a chemical modification that occurs on RNA molecules, where the hydrogen atom of adenine (A) nucleotides is replaced by a methyl group, forming N6-methyladenosine. This modification is a dynamic and reversible process that plays a crucial role in regulating various biological processes, including RNA stability, transport, translation, and degradation. Currently, there is a lack of research on the role of m6A modifications in maintaining the characteristics of RPE cells. m6A readers play a crucial role in executing the functions of m6A modifications, which prompted our investigation into their regulatory roles in the RPE.
METHODS
Phagocytosis assays, immunofluorescence staining, flow cytometry experiments, β-galactosidase staining, and RNA sequencing (RNA-seq) were conducted to assess the functional and cellular characteristics changes in retinal pigment epithelium (RPE) cells following short-hairpin RNA-mediated knockdown of insulin-like growth factor 2 mRNA-binding protein 2 (IGF2BP2). RNA-seq and ultraviolet crosslinking immunoprecipitation with high-throughput sequencing (HITS-CLIP) were employed to identify the target genes regulated by IGF2BP2. adeno-associated virus (AAV) subretinal injection was performed in 6- to 8-week-old C57 mice to reduce IGF2BP2 expression in the RPE, and the impact of IGF2BP2 knockdown on mouse visual function was assessed using immunofluorescence, quantitative real-time PCR, optical coherence tomography, and electroretinography.
RESULTS
IGF2BP2 was found to have a pronounced effect on RPE phagocytosis. Subsequent in-depth exploration revealed that IGF2BP2 modulates the mRNA stability of PAX6 and OTX2, and the loss of IGF2BP2 induces inflammatory and aging phenotypes in RPE cells. IGF2BP2 knockdown impaired RPE function, leading to retinal dysfunction in vivo.
CONCLUSIONS
Our data suggest a crucial role of IGF2BP2 as an m6A reader in maintaining RPE homeostasis by regulating the stability of PAX6 and OTX2, making it a potential target for preventing the occurrence of retinal diseases related to RPE malfunction.
Topics: Retinal Pigment Epithelium; Animals; Mice; PAX6 Transcription Factor; Homeostasis; Mice, Inbred C57BL; Otx Transcription Factors; RNA-Binding Proteins; Phagocytosis; Flow Cytometry; Gene Expression Regulation; Tomography, Optical Coherence; Electroretinography; Cells, Cultured
PubMed: 38861275
DOI: 10.1167/iovs.65.6.17