From Monocytes to M1/M2 Macrophages: Phenotypical vs. Functional Differentiation

Biomimetic mineralized mesenchymal stem cell-derived exosomes for dual modulation of ferroptosis and lactic acid-driven inflammation in acute liver injury therapy

Acute liver injury (ALI) is characterized by rapid and severe hepatocellular damage, leading to ferroptosis and an exacerbated inflammatory response. Mesenchymal stem cell-derived exosomes (MSC-exo) have emerged as a promising therapeutic strategy for ALI due to their ability to deliver antioxidants and stabilize solute carrier family 7 members 11 (SLC7A11)/glutathione peroxidase 4 (GPX4) system. In this study, we developed a novel engineered exosome, MSC-exo/MnO2@DEX, by encapsulating the anti-inflammatory drug dexamethasone (DEX) within MSC-exo and modifying its surface with manganese dioxide (MnO2) via a bionano-mineralization approach. MnO2 exhibits multi-enzymatic activity, enabling efficient scavenging of reactive oxygen species (ROS), such as hydrogen peroxide and superoxide anions. When combined with MSC-exo, MnO2 not only reduces ROS levels and generates oxygen but also stabilizes the SLC7A11/GPX4 axis, thereby protecting hepatocytes from ferroptosis. Concurrently, DEX suppresses the nuclear factor-κB (NF-κB) signaling pathway, inhibits macrophage M1 polarization, and alleviates hepatic inflammation. The oxygen produced by MnO2 catalysis further mitigates hypoxia, decreases lactic acid accumulation, and downregulates histone lactylation, synergizing with DEX to enhance NF-κB pathway inhibition and amplify anti-inflammatory effects. Transcriptomic analyses revealed that MSC-exo/MnO2@DEX significantly enhances antioxidant capacity, metabolic processes, and immune function, while improving liver function and suppressing ferroptosis, lactylation and inflammatory responses. Collectively, these findings demonstrate the therapeutic potential of MSC-exo/MnO2@DEX as an effective treatment for ALI.

Tumor-infiltrating myeloid cells; mechanisms, functional significance, and targeting in cancer therapy

Tumor-infiltrating myeloid cells (TIMs), which encompass tumor-associated macrophages (TAMs), tumor-associated neutrophils (TANs), myeloid-derived suppressor cells (MDSCs), and tumor-associated dendritic cells (TADCs), are of great importance in tumor microenvironment (TME) and are integral to both pro- and anti-tumor immunity. Nevertheless, the phenotypic heterogeneity and functional plasticity of TIMs have posed challenges in fully understanding their complexity roles within the TME. Emerging evidence suggested that the presence of TIMs is frequently linked to prevention of cancer treatment and improvement of patient outcomes and survival. Given their pivotal function in the TME, TIMs have recently been recognized as critical targets for therapeutic approaches aimed at augmenting immunostimulatory myeloid cell populations while depleting or modifying those that are immunosuppressive. This review will explore the important properties of TIMs related to immunity, angiogenesis, and metastasis. We will also document the latest therapeutic strategies targeting TIMs in preclinical and clinical settings. Our objective is to illustrate the potential of TIMs as immunological targets that may improve the outcomes of existing cancer treatments.

Noninvasive and in situ identification of the phenotypes and differentiation stages of individual living cells entrapped within hydrogels

Microscale screening platforms that allow cells to interact in three dimensions (3D) with their microenviroment have been developed as a tool for identifying the extrinsic cues that might stimulate stem cells to replicate without differentiating within artificial cultures. Though these platforms reduce the number of valuable stem cells that must be used for screening, analyzing the fate decisions of cells in these platforms can be challenging. New noninvasive approaches for identifying the lineage-specific differentiation stages of cells while they are entrapped in the hydrogels used for these 3D cultures are especially needed. Here we used Raman spectra acquired from individual, living cells entrapped within a hydrogel matrix and multivariate analysis to identify cell phenotype noninvasively and in situ. We collected a single Raman spectrum from each cell of interest while it was entrapped within a hydrogel matrix and used partial least-squares discriminant analysis (PLS-DA) of the spectra for cell phenotype identification. We first demonstrate that this approach enables identifying the lineages of individual, living cells from different laboratory lines entrapped within two different hydrogels that are used for 3D culture, collagen and gelatin methacrylate (gelMA). Then we use a hematopoietic progenitor cell line that differentiates into different types of macrophages to show that the lineage-specific differentiation stages of individual, living hematopoietic cells entrapped inside of gelMA scaffolds may be identified by PLS-DA of Raman spectra. This ability to noninvasively identify the lineage-specific differentiation stages of cells without removing them from a 3D culture could enable tracking the differentiation of the same cell over time.

Macrophage at maternal-fetal Interface: Perspective on pregnancy and related disorders

Immune cells at the maternal-fetal interface (MFI) undergo dynamic changes to facilitate fetal growth and development during pregnancy. In contrast to the adaptive immune system, where effector T cells, Tregs, and suppressor T cells play key roles in maintaining immune tolerance toward the semi-allogeneic fetus, the innate immune system-comprising decidual nature killer (dNK) cells, macrophages, and dendritic cells (DCs)-makes up a significant portion of the decidual leukocyte population. These innate immune cells are crucial in modulating trophoblast invasion, spiral artery remodeling, and apoptotic cell phagocytosis. Dysregulation of the innate immune system has been linked to impaired uterine vessel remodeling and defective trophoblast invasion, which can lead to complications such as spontaneous abortion, preeclampsia (PE), and preterm. This review focuses on recent advancements in understanding the innate immune defenses at the maternal-fetal interface and their connections to pregnancy-related diseases, with particular emphasis on the role of macrophages.

Extracellular Adipose Matrix Hydrogel Laden with Adipose-Derived Stem Cell Modulates Macrophage Polarization for Enhanced Full-Thickness Skin Wound Repair

Adipose-derived stem cells (ADSC) represent a promising approach for wound healing, while the limited survival rate has restricted their application. To address this, we equipped a hydrogel from acellular porcine adipose tissue (HAPA) with ADSC to fabricate the HAPA + ADSC composite hydrogel. In addition to serving as a carrier for stem cell delivery, the bioactive components of the HAPA hydrogel support immune regulation and tissue repair. In this study, we demonstrated that the HAPA + ADSC composite could effectively modulate macrophage polarization, promote angiogenesis, and regulate extracellular matrix (ECM) deposition and remodeling, thereby substantially accelerating wound healing. Additionally, transcriptomic sequencing analysis indicated that the HAPA + ADSC composite upregulated Nfkbia and Nfkbie to inhibit the nuclear transcription of RelA-p50 heterodimer so that macrophages polarization toward an M1 phenotype is suppressed. The combined effects of ADSC and HAPA hydrogel make it a promising candidate for functional skin wound healing.

Degradation of WE43 Magnesium Alloy in Vivo and Its Degradation Products on Macrophages

Due to their biocompatibility, biodegradability, and suitable mechanical properties, magnesium-based biodegradable implants are emerging as a promising alternative to traditional metal implants. The Mg-4Y-3RE (WE43) biodegradable alloy is among the most extensively studied and widely utilized magnesium alloys in clinical applications. As an absorbable and degradable metallic material, magnesium alloys undergo gradual degradation, wear, and fracture within the body. These alloys reduce the long-term risks associated with permanent implants but generate insoluble byproducts that accumulate in surrounding tissues. Following the implantation of magnesium alloys, granulation tissue and fibrous encapsulation typically form around the material. However, limited research has addressed the interaction between insoluble byproducts of magnesium alloys and macrophages. This study focused on the biological effects of macrophages during the second stage of the host inflammatory response in the degradation process of magnesium alloy. Using subcutaneous implantation of WE43 magnesium alloy sheets, observations were made regarding the degradation components, morphological changes in surrounding tissues, and the biological effects of macrophages upon phagocytosis of insoluble byproducts. The primary degradation products of WE43 in vivo were identified as Ca3 (PO4)2, Mg3(PO4)2, Na3PO4, NaCa (PO4), MgSO4, MgCO3, NaCl, Mg24Y5, and Mg12YNd. Postimplantation, levels of IL-1β and IL-18 in adjacent tissues significantly increased (p < 0.05). By 8 weeks, compared to nitinol alloy, significant thickening of the fibrous capsule (p < 0.05) was observed, accompanied by substantial inflammatory cell infiltration, vascularization, and the presence of macrophages and multinucleated giant cells. Macrophages were observed extending pseudopodia to enclose and phagocytose particles, forming phagosomes and creating a relatively isolated microenvironment around the engulfed substances, where further particle degradation occurred. Following the phagocytosis of degradation products, macrophages exhibited increased lysosome numbers, mitochondrial swelling and damage, phagolysosome formation, and autophagosome development. Furthermore, the degradation products were observed to induce elevated reactive oxygen species (ROS) production in macrophages, activation of P2X7 receptors, enhanced IL-6 secretion, endoplasmic reticulum stress, autophagy, and activation of the NLRP3 inflammasome pathway. This study provides novel insights and contributes a theoretical foundation for a more comprehensive understanding of magnesium alloy degradation in vivo.

Cellular crosstalk in fibrosis: insights into macrophage and fibroblast dynamics

Pathological fibrosis, the excessive deposition of extracellular matrix and tissue stiffening that causes progressive organ dysfunction, underlies diverse chronic diseases. The fibrotic microenvironment is driven by the dynamic microenvironmental interaction between various cell types; macrophages and fibroblasts play central roles in fibrotic disease initiation, maintenance, and progression. Macrophage functional plasticity to microenvironmental stimuli modulates fibroblast functionality by releasing pro-inflammatory cytokines, growth factors, and matrix remodeling enzymes that promote fibroblast proliferation, activation, and differentiation into myofibroblasts. Activated fibroblasts and myofibroblasts serve as the fibrotic effector cells, secreting extracellular matrix components and initiating microenvironmental contracture. Fibroblasts also modulate macrophage function through the release of their own pro-inflammatory cytokines and growth factors, creating bidirectional crosstalk that reinforces the chronic fibrotic cycle. The intricate interplay between macrophages and fibroblasts, including their secretomes and signaling interactions, leads to tissue damage and pathological loss of tissue function. In this review, we examine macrophage-fibroblast reciprocal dynamic interactions in pathological fibrotic conditions. We discuss the specific lineages and functionality of macrophages and fibroblasts implicated in fibrotic progression, with focus on their signal transduction pathways and secretory signalling that enables their pro-fibrotic behaviour. We then finish with a set of recommendations for future experimentation with the goal of developing a set of potential targets for anti-fibrotic therapeutic candidates. Understanding the cellular interactions between macrophages and fibroblasts provides valuable insights into potential therapeutic strategies to mitigate fibrotic disease progression.

Tumor-Associated Macrophages as Key Modulators of Disease Progression in Diffuse Large B-Cell Lymphoma

With the advent of new therapeutic approaches, there is hope that anticancer treatment will eventually be possible without the use of chemotherapy. Efficient immunotherapeutic options have recently emerged in many cancers, offering a less aggressive approach, with overall better tolerance, making them also suitable for frail patients. Response to immunotherapy relies on the availability, functionality, and efficacy of the host's immune effector mechanisms. One of the key factors determining the efficacy of immunotherapy is the tumor microenvironment, which encompasses various immune effectors, including macrophages, which play a crucial role in regulating immune responses through phagocytosis and antigen presentation. Macrophages are prototypically divided, according to their polarization, into either the pro-inflammatory M1 type or the anti-inflammatory M2 type. In the tumor microenvironment, M2-polarized macrophages, known as tumor-associated macrophages (TAMs), are the predominant phenotype and are associated with tumor progression. The M1/M2 paradigm contributes to the understanding of tumor progression. Due to the variable microenvironment, the mechanisms regulating TAMs can vary across different cancers. Variations in TAM polarization may account for the different treatment responses in patients with similar diseases. This paper investigates the connection between TAMs, disease progression, and treatment responses in the most frequent solid hematologic cancer, diffuse large B-cell lymphoma.

Oxidative Phosphorylation Pathway in Ankylosing Spondylitis: Multi-Omics Analysis and Machine Learning

INTRODUCTION

Ankylosing spondylitis (AS) is a chronic inflammatory disease affecting the axial skeleton, characterized by immune microenvironment dysregulation and elevated cytokines like TNF-α and IL-17. Mitochondrial oxidative phosphorylation (OXPHOS), crucial for immune cell function and survival, is implicated in AS pathogenesis. This study explores OXPHOS-related mechanisms in AS, identifies key genes using machine learning, and highlights potential therapeutic targets for precision medicine.

MATERIALS AND METHODS

Peripheral blood mononuclear cells (PBMCs) bulk transcriptomic and single-cell RNA sequencing (scRNA-seq) data from AS patients were analyzed to investigate the role of the OXPHOS pathway in AS. Weighted gene co-expression network analysis (WGCNA) was performed to identify key gene modules associated with OXPHOS. Machine learning techniques, including support vector machine with recursive feature elimination (SVM-RFE), random forest, and least absolute shrinkage and selection operator (LASSO), were applied to identify significant AS-related genes. Real-time PCR (RT-PCR) was used to quantify gene expression, examine their patterns in specific cell subtypes, and explore their functional implications.

RESULTS

Pathway enrichment analysis identified OXPHOS as a significantly enriched pathway distinguishing AS patients from healthy controls, with high normalized enrichment scores and significant group separation in principal component analysis. ScRNA-seq revealed significantly higher OXPHOS scores in AS patients, especially in dendritic cells (DCs) and monocytes, highlighting cell type-specific dysregulation. WGCNA identified two key gene modules (MEyellow and MEtan) that are closely associated with OXPHOS. Three hub genes-LAMTOR2, APBB1IP, and DGKQ-were screened using machine learning methods and validated by RT-PCR and scRNA-seq. Among them, LAMTOR2 was significantly more highly expressed in patients with AS, and functional analyses showed that it plays a role in promoting TH17 cell differentiation, which highlights its potential as a therapeutic target for ankylosing spondylitis.

CONCLUSION

This multi-omics study provides valuable insights into the complex interplay between OXPHOS and AS. The identified genes, particularly LAMTOR2, serve as potential therapeutic targets, contributing to our understanding of AS mechanisms and paving the way for precision medicine in AS treatment.

Impact of mechanotransduction on gene expression changes in periodontal ligament during orthodontic tooth movement

INTRODUCTION

The periodontal ligament (PDL) is a structure between the alveolar bone and cementum, essential for tooth stability and composed of diverse cell types. Mohawk homeobox (Mkx) is a master transcription factor that regulates tendon and ligament homeostasis. However, the specific cell populations expressing Mkx and its role in mechanotransduction during orthodontic tooth movement (OTM) remain unclear.

MATERIALS AND METHODS

We conducted single-cell RNA sequencing on wild-type rat PDL at 0 day, 1 week, and 2 weeks of post-OTM using coil springs to elucidate Mkx's function and the changes in cell populations under continuous mechanical stimulation. In addition, RT-qPCR was performed to assess the relationship between tenogenic gene expression and Mkx expression in human PDL cells.

RESULTS

The rat PDL was identified to consist of 14 clusters, with Mkx and Scleraxis (Scx) expressed in distinct cell populations. Collagen and ECM production increased throughout the OTM period, while the sterile inflammatory response was initially heightened and later diminished, indicating that bone remodeling occurs later in the inflammatory response. Overexpression of MKX in human PDL cells enhanced COL1A1 and DECORIN expression.

CONCLUSION

Mechanical stimulation of the PDL appears to trigger an aseptic inflammatory response that disrupts PDL homeostasis and promotes bone remodeling. Mkx may exert a protective effect on the PDL during mechanical stimulation.

Amelioration of imiquimod induced psoriasis through reduction in IL-17A and Th17 population by dihydromyricetin involves regulation of RORγt pathway

BACKGROUND AND PURPOSE

Psoriasis is a chronic inflammatory skin disorder affecting approximately 125 million people. IL-17 A secreted from Th17 cells plays a major role in elucidating psoriasis. Dihydromyricetin (DHM) is plant derived flavonoid isolated from leaves and stems of Rattan tea (Ampelopsis grossedentata). Reports indicate anti-inflammatory property of DHM but no information is currently available on its mechanism of action or effect on IL17 producing Th17 cells and exact role in psoriasis.

EXPERIMENTAL APPROACH

DHM shows strong anti-inflammatory properties in vitro, DHM reduced LPS-induced ROS generation, and pro-inflammatory cytokines in macrophages. The efficacy of DHM against chronic inflammatory disorder in vivo was investigated in imiquimod-induced psoriasis established in male BALB/C mice as this model closely resembles human psoriasis. Immunophenotyping and cytokine production were observed by flow cytometry, the status of gene expression was determined by real-time PCR, and nuclear co-localization and immunofluorescence of skin tissue were studied using confocal microscopy.

KEY RESULTS

We observed increased inflammatory parameters in imiquimod treated diseased animals and the application of DHM topically and orally reduced the inflammatory parameters and improved indicators of cardiac damage prominent in psoriatic conditions. In our study, we found that the application of DHM dose-dependently reduced the percentage of IL-17 A-producing T cell population and reduced the nuclear co-translocation of RORγt in psoriatic T cells and possibly also influenced upstream IL-6 signaling.

CONCLUSION AND IMPLICATIONS

Our study suggests that DHM effectively alleviates psoriatic symptoms, and its mechanism of action involves the regulation of RORγt pathway in T cells.

Role of Tumor-Associated Macrophages in Breast Cancer Immunotherapy

Breast cancer (BC) is the second leading cause of death among women worldwide. Immunotherapy has become an effective treatment for BC patients due to the rapid development of medical technology. Considerable breakthroughs have been made in research, marking the beginning of a new era in cancer treatment. Among them, various cancer immunotherapies such as immune checkpoint inhibitors (ICIs), cancer vaccines, and adoptive cell transfer are effective and have good prospects. The tumor microenvironment (TME) plays a crucial role in determining the outcomes of tumor immunotherapy. Tumor-associated macrophages (TAMs) are a key component of the TME, with an immunomodulatory effect closely related to the immune evasion of tumor cells, thereby affecting malignant progression. TAMs also significantly affect the therapeutic effect of ICIs (such as programmed death 1/programmed death ligand 1 (PD-1/PD-L1) inhibitors). TAMs are composed of multiple heterogeneous subpopulations, including M1 phenotypes macrophages (M1) and M2 phenotypes macrophages (M2). Furthermore, they mainly play an M2-like role and moderate a variety of harmful consequences such as angiogenesis, immunosuppression, and metastasis. Therefore, TAMs have become a key area of focus in the development of tumor therapies. However, several tumor immunotherapy studies demonstrated that ICIs are effective only in a small number of solid cancers, and tumor immunotherapy still faces relevant challenges in the treatment of solid tumors. This review explores the role of TAMs in BC immunotherapy, summarizing their involvement in BC development. It also explains the classification and functions of TAMs, outlines current tumor immunotherapy approaches and combination therapies, and discusses the challenges and potential strategies for TAMs in immuno-oncology treatments.

The role of IGF2BP2 in macrophage-mediated NLRP3 inflammasome activation in the pathogenesis of dry AMD

BACKGROUND

Dry age-related macular degeneration (AMD) is a common chronic degenerative eye disease for which there is currently no effective treatment. Insulin-like growth factor 2 mRNA-binding protein 2 (IGF2BP2) is a recently identified m6A reader that binds RNA and maintains its stability, thereby participating in various biological processes. However, its role in dry AMD remains unclear.

METHODS

In this study, we investigated the role of IGF2BP2 in macrophage NLRP3 inflammasomes using a sodium iodate-induced dry AMD model.

RESULTS

Our results demonstrated that IGF2BP2 is highly expressed in the retinal-choroidal tissue induced by sodium iodate, with its effects primarily occurring in macrophages. The loss of IGF2BP2 ameliorating dry AMD. Mechanistically, methylated NLRP3 transcripts were subsequently directly recognized by the specific m 6 A "reader", IGF2BP2, to prevent NLRP3 mRNA degradation. Furthermore, in in vivo experiments, to maintain the eye's "immune privilege", we employed mesoporous silica-based cell therapy to target and regulate macrophage IGF2BP2, providing a foundation for the evaluation and translation of therapies targeting this gene.

CONCLUSION

our study reveals that the molecular mechanism of dry AMD pathogenesis involves IGF2BP2-mediated NLRP3 inflammasome activation in macrophages, highlighting IGF2BP2 as a promising biomarker and therapeutic target for dry AMD treatment.

Integrating network pharmacology and in vivo pharmacological validation to explore the gastroprotective mechanism of Sotetsuflavone against indomethacin-induced gastric ulcer in rats: Involvement of JAK2/STAT3 pathway

Sotetsuflavone (SF) is an antioxidant flavonoid derived from the Cycas thouarsii R.Br. plant. Although SF regulates numerous cellular pathways influencing inflammation, its antiinflammatory benefits against gastric ulcers are less well-studied. Hence, it is imperative to thoroughly understand the potential gastroprotective mechanisms of SF. This study aimed to explore the effectiveness of SF against indomethacin (IND)-induced gastric ulcers. Network analysis and molecular docking were used to identify the specific targets and pathways related to SF and stomach ulcers. To validate the in vivo pharmacological action of SF, 36 rats were divided into six groups. Ulcer index (UI), protective percentage (PP), gastric mucosal mediators, oxidant/antioxidant status, and inflammatory markers (MIF, M-CSF, and AIF-1) were assessed. Additionally, the expression of PI3K, Akt, Siah2, SOCS3, JAK2, and STAT3 was determined. Stomach histopathology and immunohistochemistry were done. Network pharmacology detected 46 overlapping targets between SF and stomach ulcers, with HIF1A as the primary target among the top hubs. The network also revealed that JAK/STAT, PI3K/Akt, and HIF-1A signaling are among the top 50 markedly enriched KEGG pathways. Furthermore, docking results confirmed that SF has a strong binding affinity towards SOCS3, JAK2, STAT3, M-CSF (CSF-1), and AIF-1. Therefore, we hypothesized that the JAK2/STAT3 pathway may be primarily responsible for SF antiinflammatory action. Through up-regulating SOCS3, SF altered the PI3K/Akt pathway, mitigating oxidative stress, blocking the outflow of inflammatory mediators, and impeding gastric ulcer development. Overall, SF, by the SOCS3-mediated JAK2/STAT3 suppression, might considerably reduce oxidative stress, inflammation, and ulceration caused by indomethacin in the stomach.

Can pyridoxine function as an anti-pyroptosis agent? A narrative review

BACKGROUND

Pyroptosis, a highly inflammatory form of programmed cell death, plays a key role in diseases such as sepsis, rheumatoid arthritis, Alzheimer's disease, and COPD. It is driven by inflammasome activation, leading to the release of pro-inflammatory cytokines. Pyridoxine (Vitamin B6), an essential micronutrient with known anti-inflammatory effects, has been suggested as a potential regulator of inflammasome activation and pyroptosis. This review examines current evidence on pyridoxine's role in modulating pyroptosis.

METHODS

A literature search was conducted in PubMed, Scopus, and Web of Science for studies published between 2014 and 2024. The search focused on pyridoxine's relationship with inflammation, inflammasomes, and pyroptosis pathways using keywords such as "pyridoxine," "Vitamin B6," "pyroptosis," "inflammasome," "caspase-1," and "gasdermin D." Both preclinical and human studies were reviewed, with emphasis on molecular mechanisms underlying pyridoxine's anti-inflammatory effects.

RESULTS

Studies consistently showed that pyridoxine reduced inflammasome activation, decreased pro-inflammatory cytokine production, and inhibited caspase-1 (CASP-1) activity, thereby suppressing pyroptosis. Human studies, though indirect, linked higher pyridoxine levels to reduced systemic inflammation, suggesting a possible anti-pyroptotic effect.

CONCLUSIONS

Pyridoxine shows potential as an anti-pyroptotic agent due to its anti-inflammatory and immunomodulatory properties. However, further well-designed clinical trials are needed to confirm its role in controlling pyroptosis, especially in diseases associated with excessive inflammasome activation.

ADAR1-high tumor-associated macrophages induce drug resistance and are therapeutic targets in colorectal cancer

BACKGROUND

Colorectal cancer (CRC) is considered the third most common type of cancer worldwide. Tumor-associated macrophages (TAMs) have been shown to promote drug resistance. Adenosine-to-inosine RNA-editing, as regulated by adenosine deaminase acting on RNA (ADAR), is a process that induces the posttranscriptional modification of critical oncogenes. The aim of this study is to determine whether the signals from cancer cells would induce RNA-editing in macrophages.

METHODS

The effects of RNA-editing on phenotypes in macrophages were analyzed using clinical samples and in vitro and in vivo models.

RESULTS

The intensity of the RNA-editing enzyme ADAR1 (Adenosine deaminase acting on RNA 1) in cancer and mononuclear cells indicated a strong positive correlation between the nucleus and cytoplasm. The ADAR1-positive mononuclear cells were positive for CD68 and CD163, a marker for M2 macrophages. Cancer cells transport pro-inflammatory cytokines or ADAR1 protein directly to macrophages via the exosomes, promoting RNA-editing in AZIN1 (Antizyme Inhibitor 1) and GLI1 (Glioma-Associated Oncogene Homolog 1) and resulting in M2 macrophage polarization. GLI1 RNA-editing in the macrophages induced by cancer cells promotes the secretion of SPP1, which is supplied to the cancer cells. This activates the NFκB pathway in cancer cells, promoting oxaliplatin resistance. When the JAK inhibitors were administered, oncogenic RNA-editing in the macrophages was suppressed. This altered the macrophage polarization from M2 to M1 and decreased oxaliplatin resistance in cancer cells.

CONCLUSIONS

This study revealed that ADAR1-high TAMs are crucial in regulating drug resistance in CRC and that targeting ADAR1 in TAMs could be a promising treatment approach for overcoming drug resistance in CRC.

EdU tracking of leukocyte recruitment in mouse models of ischemic stroke and sterile lung inflammation

The discovery of copper(I)-catalyzed azide-alkyne cycloaddition (click chemistry) has significantly advanced the detection of proliferating cells by utilizing 5-ethynyl-2'-deoxyuridine (EdU). EdU, a thymidine analogue, is incorporated into DNA during replication and detected by the direct reaction with an azide-conjugated fluorophore. Traditionally, dividing cells are labeled using 5-bromodeoxyuridine (BrdU), another nucleotide analogue. However, BrdU detection is a harsh method that requires substantial sample processing, unlike EdU detection. EdU is classically used to identify proliferating cells; however, we report a streamlined methodology that uses EdU to label and track leukocyte recruitment that is compatible with flow cytometry and microscopy and preserves transgenic fluorophores. EdU labeling was performed in two different models of sterile inflammation: ischemic stroke and hydrochloric acid aspiration. EdU injection was timed to differentially label circulating monocytes, neutrophils and T cells. Tissue analysis showed EdU-positive monocytes and T cells were enriched in both inflammatory models. This suggests that recently divided monocytes and T cells are preferentially recruited to these vascular beds during inflammation and highlights the utility of this labeling approach to track leukocyte subtypes longitudinally during inflammation.

Addition of metformin to anti-PD-1/PD-L1 drugs activates anti-tumor immune response in peripheral immune cells of NSCLC patients

Immunotherapy has transformed the treatment landscape for non-small cell lung cancer (NSCLC), yet achieving lasting benefits remains a challenge. The resistance mechanisms to immunotherapy are complex, involving interactions between tumor cells and immune cells that are not fully understood. Metformin, an FDA-approved diabetes medication, shows promise in enhancing immunotherapy efficacy by boosting anti-tumor immune responses, although the underlying molecular pathways are still being investigated. This study utilized co-culture models of cancer and immune cells to explore the effects of combining metformin with anti-PD-1/PD-L1 therapies on the anti-tumor immune response in LKB1 mutant (LKB1mut) versus wild-type (LKB1wt) NSCLC cells, alongside peripheral blood immune cells from NSCLC patients. The transcriptomic profiles of LKB1mut and LKB1wt NSCLC cells were characterized via bulk RNA sequencing to understand gene expression changes induced by metformin. Patients with advanced-stage NSCLC provided peripheral blood mononuclear cells (PBMCs) for analysis. The study assessed metformin's impact both alone and in combination with anti-PD-1/PD-L1 agents on innate immune pathways. Results indicated that metformin activated the cGAS-STING pathway and interferons in PBMCs, enhancing their anti-tumor capabilities. Notably, immune cells treated with metformin and immunotherapy exhibited synergistic effects, significantly reducing colony formation in LKB1mut NSCLC cells. Additionally, monocytes from NSCLC patients showed decreased viability of NSCLC cells in co-culture, independent of LKB1 status, and shifted towards an anti-tumor M1 phenotype with combined treatment. These findings were supported by 3D co-culture models involving tumor spheroids and patient-derived organoids, highlighting a novel biological rationale for using metformin alongside immunotherapeutic agents to boost anti-tumor activity across various immune cell subsets derived from NSCLC patients.

Tertiary Lymphoid Structures Are Associated with Progression-Free Survival of Peripheral Neuroblastic Tumor Patients

Background/Objectives: Peripheral neuroblastic tumors (pNT) are a biologically heterogeneous group of embryonal tumors that derive from the neural crest and affect the sympathetic nervous system. So far, little is known about the complex immune landscape in these rare childhood cancers. Methods: We focused on the immune cell infiltrate of treatment-naïve pNT from 24 patients, including high-risk neuroblastoma (HR-NBL), non-high-risk neuroblastoma (NHR-NBL), ganglioneuroblastoma (GNBL), and rare ganglioneuroma (GN). To gain novel insights into the immune architecture of these pNT subtypes, we used multiplex immunohistochemistry, multispectral imaging, and algorithm-based data evaluation to detect and characterize T cells, B cells, neutrophils, macrophages, and tertiary lymphoid structures (TLS). Results: The majority of the investigated tumor-infiltrating immune cells were macrophages and T cells. Their detailed phenotypic characterization revealed high proportions of M2-like macrophages as well as activated GrzB+ CD8+ and PD-1+ T lymphocytes. Proportions of these T cell phenotypes were significantly increased in GN compared to HR-NBL, NHR-NBL, or GNBL. In addition, TLS occurred in 11 of 24 patients, independent of immune cell frequencies in the whole tissues. Interestingly, all GN, most GNBL, but only a few NBL contained TLS. We distinguished between three TLS maturation stages that were present irrespective of the pNT subtype. The majority belonged to mature TLS of the primary follicle state. Mature LAMP3+ dendritic cells were also found, predominantly in T cell zones of TLS. Furthermore, TLS presence identified pNT patients with significantly prolonged progression-free survival in contrast to all other analyzed immunological features. Conclusions: We propose TLS to be a potential prognostic marker for pNT to predict patient outcomes.

Regulatory T cells in solid tumor immunotherapy: effect, mechanism and clinical application

The tumor-immune response is mobilized to suppress tumorigenesis, while the immune microenvironment and lymph node microenvironment are formed gradually during tumor progression. In fact, tumor surface antigens are not easily recognized by antigen-presenting cells. So it is hard for the immune system to kill the newly formed tumor cells effectively. In a normal immune environment, immune function is always suppressed to maintain the stability of the body, and regulatory T cells play an important role in maintaining immune suppression. However, during tumorigenesis, the suppression of regulatory T cell immune functions is more likely to contribute to tumor cell proliferation and migration leading directly to tumor progression. Therefore, focusing on the role of regulatory T cells in tumor immunity could improve tumor immunotherapy outcomes in the clinic. Regulatory T cells are more mature in hematologic system tumors than in solid tumors. However, there are continuing efforts to apply regulatory T cells for immunotherapy in solid tumors. This review describes the role of regulatory T cells in solid tumor immunotherapy from the perspective of prognosis, immune microenvironment remodeling, and current clinical applications. This summary could help us better understand the mechanisms of regulatory T cells in solid tumor immunotherapy and further expand their clinical application.

Syndecan-3 positively regulates the pro-inflammatory function of macrophages

The tumour microenvironment (TME) is a highly structured ecosystem that surrounds a tumour and plays a crucial role in tumorigenesis. As one of the most abundant cell types in the TME, tumour-associated-macrophages (TAMs) can promote disease progression and resistance to therapy. Syndecan-3 (SDC3) is a cell-surface heparan sulphate proteoglycan expressed by TAMs, although its functional relevance in these cells remains unknown. Here, we demonstrated that pro-inflammatory cytokines drive the expression of SDC3 on the cell surface of macrophages. Genetic ablation of SDC3 in macrophages led to aberrant proliferation, adhesion and expression of CD40 and CD86 surface markers. Moreover, SDC3 defective macrophages exhibited distinctive gene expression patterns, leading to impaired tumour cell phagocytosis and increased tumour cell proliferation. Mechanistically, a decrease in the secretion of pro-inflammatory cytokines was observed in SDC3 KO macrophages, concomitant with impaired T cell effector functions. Additionally, a higher angiogenic capacity was observed in endothelial cells when co-cultured with macrophages deficient for SDC3, possibly mediated through an increased release of VEGFA, PECAM-1 and IL-8 by SDC3 KO cells. Collectively, we have identified SDC3 as a modulator of macrophage functions aiming at supporting a pro-inflammatory and anti-tumour phenotype in these cells.

Enhancing antitumor immunity: the role of immune checkpoint inhibitors, anti-angiogenic therapy, and macrophage reprogramming

Cancer treatment has long been hindered by the complexity of the tumor microenvironment (TME) and the mechanisms that tumors employ to evade immune detection. Recently, the combination of immune checkpoint inhibitors (ICIs) and anti-angiogenic therapies has emerged as a promising approach to improve cancer treatment outcomes. This review delves into the role of immunostimulatory molecules and ICIs in enhancing anti-tumor immunity, while also discussing the therapeutic potential of anti-angiogenic strategies in cancer. In particular, we highlight the critical role of endoplasmic reticulum (ER) stress in angiogenesis. Moreover, we explore the potential of macrophage reprogramming to bolster anti-tumor immunity, with a focus on restoring macrophage phagocytic function, modulating hypoxic tumor environments, and targeting cytokines and chemokines that shape immune responses. By examining the underlying mechanisms of combining ICIs with anti-angiogenic therapies, we also review recent clinical trials and discuss the potential of biomarkers to guide and predict treatment efficacy.

Type I IFN receptor blockade alleviates liver fibrosis through macrophage-derived STAT3 signaling

Liver macrophages play a role in the development of liver fibrosis progression via the regulation of inflammatory signaling. However, the precise mechanisms of macrophages contributing to liver fibrosis progression remain unclear. Using a preclinical model of CCl4-treated mice, we determined the composition of immune cells and the alteration of inflammatory gene expression. Our findings revealed a significant increase in liver macrophages, particularly those derived from infiltrating blood monocytes, in fibrotic mice. Moreover, the expression levels of type I IFN signature genes such as IFNα, IFNβ, ISG15, USP18, Ifi44, Ifit1, Ifit2, IRF3, and IRF7 were elevated in fibrotic mice. To determine the role of type I IFN signaling in liver fibrosis, we administered an IFNAR-1 antibody to block this pathway for 3 days prior to harvesting the liver. Notably, IFNAR-1 blockade reduced macrophage numbers compared to control mice and alleviated liver fibrosis in mice with increased hepatocyte proliferation and apoptosis. The ratio of P-STAT3/P-STAT1 in monocyte-derived macrophages was increased in the IFNAR-1 blockade group compared to fibrotic mice, and this was related to the appearance of M2 macrophage differentiation. Additionally, single-cell RNA-seq analysis indicated that IFNAR blockade affected inflammatory pathways involved in hepatocyte regeneration and fibrosis prevention. Taken together, IFNAR-1 blockade alleviates liver fibrosis progression by modulating macrophage inflammatory responses. These results provide insights for developing anti-fibrotic therapies against type I IFN signaling.

Comparison of human macrophages derived from peripheral blood and bone marrow

Macrophage differentiation, phenotype, and function have been assessed extensively in vitro by predominantly deriving human macrophages from peripheral blood. It is accepted that there are differences between macrophages isolated from different human tissues; however, the importance of anatomical source for in vitro differentiation and characterization is less clear. Here, phenotype and function were evaluated between human macrophages derived from bone marrow or peripheral blood. Macrophages were differentiated by adherence of heterogenous cell populations or CD14 isolation and polarized with IFNγ and LPS or IL-4 and IL-13 for 48 hours before evaluation of phenotype and phagocytic capacity. The presence of stromal cells in bone marrow heterogenous cultures resulted in a reduction in macrophage purity compared to peripheral blood, which was negated after CD14 isolation. Phenotypically, monocyte-derived macrophages (MDMs) derived from peripheral blood and bone marrow resulted in similar expression of classical and polarized macrophages markers, including CD14, HLA-DR, CD38, and CD40 (increased after IFNγ/LPS), and CD11b and CD206 (elevated after IL-4/IL-13). Functionally, these cells also showed similar levels of Fc-independent and Fc-dependent phagocytosis, although there was a nonsignificant reduction of Fc-dependent phagocytosis in the bone marrow derived macrophages after IFNγ/LPS stimulation. In summary, we have identified that human MDMs differentiated from peripheral blood and bone marrow showed similar characteristics and functionality, suggesting that isolating cells from different anatomical niches does not affect macrophage differentiation after CD14 isolation. Consequently, due to high yield and ready availability peripheral blood derived macrophages are still the most suitable source.

High-dimensional tissue profiling of immune cell responses in chronic lung allograft dysfunction

PURPOSE

The immunological drivers of chronic lung allograft dysfunction (CLAD), the major barrier to long-term survival after lung transplantation, are poorly understood at a tissue level. Tissue imaging using mass spectrometry with laser ablation of regions of interest offers single-cell resolution of distinct immune cell populations and their spatial relationships and may improve our understanding of CLAD pathophysiology.

METHODS

Lung tissue from 23 lung transplant recipients, 20 with and 3 without CLAD, was sectioned and stained with a 40-plex antibody panel before 81 regions of interest from airways, blood vessels and lung parenchyma were laser ablated.

RESULTS

190,851 individual segmented cells across 41 mm2 tissue were captured before 26 distinct immune and structural cell populations were identified and interrogated across CLAD phenotypes. CLAD was associated with expansion of cytotoxic T cells, γδ T cells and plasma cells and M2 macrophage polarization compared with non-CLAD. Within CLAD, bronchiolitis obliterans syndrome was characterized by more γδ T cells and fewer Th1 cells than restrictive allograft syndrome. Both adaptive and innate immune cells were involved in the temporal evolution of fibrotic remodeling. Although fibrosis seemed to be partially associated with different factors in restrictive allograft syndrome (M2 macrophages, Th1 cells) and in bronchiolitis obliterans syndrome (γδ T cells).

CONCLUSION

Imaging mass cytometry enables in-depth analyses of immune cell phenotypes in their local microenvironment. Using this approach, we identified major differences in cell populations in CLAD versus non-CLAD and in BOS versus RAS, with novel insights into the fibrotic progression of CLAD.

Predicting the evolution from first-episode psychosis to mood or psychotic disorder: A systematic review of biological markers

BACKGROUND AND HYPOTHESIS

The development of paraclinical tools to assist clinical assessment is already widespread in nearly all other medical specialties. In psychiatry, many efforts are being made to improve management strategies using these new techniques. The first episode psychosis (FEP) is a clinical entity whose evolution after onset is difficult to predict in the current state of our practices. Our main objective was to identify from the literature the most promising biological markers for early prediction of thymic or psychotic trajectories following FEP.

STUDY DESIGN

We performed a systematic literature review on 4 databases: PubMed, Scopus, PsycINFO, and Web of Science following PRISMA guidelines and using search terms related to FEP and biomarkers.

STUDY RESULTS

Eight studies were included in our final analysis. Several biomarkers showed promising discriminatory capacities for predicting post-FEP evolution: the interleukins IL-6, IL-12p40, IL-1β, and the mRNA expression levels of the DICER-1 and AKT-1 genes. Other studies that opted for broad-spectrum strategies also highlighted new leads for the discovery of additional biomarkers.

CONCLUSIONS

Overall, our results indicate the value of replicating studies targeting the analysis of the predictive capacities of several biological markers. It also appears important to homogenize methodologies and favor the construction of predictive models on several of these markers to reinforce their statistical significance.

Differential homing of monocytes and neutrophils in the epithelial layer of HSV-1 infected cornea regulates viral dissemination and wound healing

PURPOSE

To ascertain the homing of monocytes and neutrophils in the epithelium versus stroma of HSV-1 infected corneas at different stages of infection and functional significance of their anatomical location in virus-infected corneas.

METHODS

The corneas of C57BL/6J mice were infected with HSV-1 McKrae. Mice were euthanized on different days post-infection. The epithelium and stroma were separated from the infected corneas, and flow cytometry was performed to characterize the myeloid cell subsets in the epithelium versus the stromal layers of an infected cornea. MACS columns were used to purify neutrophils or deplete myeloid cells from infected corneas. Corneal epithelial scratch assay was performed to ascertain the impact of neutrophils on epithelium wound healing.

RESULTS

Our results showed a biphasic influx of monocytes in the epithelial but not the stromal layer of HSV-1-infected corneas. Furthermore, we noted the predominance of monocytes over neutrophils in the epithelium and the stromal layer of the cornea during the pre-clinical stage of corneal HSV-1 infection. However, neutrophils were the major myeloid cell subset in the epithelium and stroma during the clinical disease period of infection. Removal of monocytes from the infected epithelial layer during the pre-clinical stage promotes the dissemination of the virus. Interestingly, neutrophils localized in the corneal epithelium inhibit corneal epithelial wound healing.

CONCLUSIONS

Together, our data suggest that differential kinetics of monocytes and neutrophils homing in the epithelial layer regulate viral dissemination and epithelial wound healing in HSV-1-infected corneas.

Effect of molecular weight of tyramine-modified hyaluronan on polarization state of THP-1 and peripheral blood mononuclear cells-derived macrophages

The immunomodulatory properties of hyaluronan and its derivatives are key to their use in medicine and tissue engineering. In this work we evaluated the capability of soluble tyramine-modified hyaluronan (THA) synthesized from hyaluronan of two molecular weights (low Mw = 280 kDa and high Mw = 1640 kDa) for polarization of THP-1 and peripheral blood mononuclear cells (PBMCs)-derived macrophages (MΦs). We demonstrate the polarization effects of the supplemented THA by flow cytometry and bead-based multiplex immunoassay for the THP-1 derived MΦs and by semi-automated image analysis from confocal microscopy, immunofluorescent staining utilizing CD68 and CD206 surface markers, RT-qPCR gene expression analysis, as well as using the enzyme-linked immunosorbent assay (ELISA) for PBMCs-derived MΦs. Our data indicate that supplementation with LMW THA drives changes in THP-1 derived MΦs towards a pro-inflammatory M1-like phenotype, whereas supplementation with the HMW THA leads to a more mixed profile with some features of both M1 and M2 phenotypes, suggesting either a heterogeneous population or a transitional state. For cells directly sourced from human patients, PMBCs-derived MΦs, results exhibit a higher degree of variability, pointing out a differential regulation of factors including IL-10 and CD206 between the two cell sources. While human primary cells add to the clinical relevance, donor diversity introduces wider variability in the dataset, preventing drawing strong conclusions. Nevertheless, the MΦs profiles observed in THP-1 derived cells for treatments with LMW and HMW THA are generally consistent with what might be expected for the treatment with non-modified hyaluronans of respective molecular weights, confirming the known association holds true for the chemically tyramine-modified hyaluronan. We stipulate that these responses will provide basis for more accurate in vivo representation and translational immunomodulatory guidance for the use of THA-based biomaterials to a wider biomaterials and tissue engineering communities.

Delivery of butyrate to the lower gut by polymeric micelles prolongs survival of distal skin allografts

The microbiota composition is known to influence the kinetics of graft rejection, but many questions remain as to whether/how microbiota-derived metabolites affect graft outcome. We investigated the effects of the short-chain fatty acid butyrate, a product of dietary fiber fermentation. Sustained intragastric administration of a micelle-based formulation of butyrate (butyrate micelle [ButM]) that releases its cargo in the lower gastrointestinal tract elevated cecal butyrate content and significantly prolonged minor-mismatched and major-mismatched skin allograft survival in mice. While ButM did not influence regulatory T cells or the adaptive alloimmune responses we tested, it modulated the myeloid cell compartment. At steady state, ButM treatment reduced the number of circulating Ly6ChiCD11b+ monocytes and other myeloid cells in secondary lymphoid organs and skin, altered their expression of genes involved in mitochondrial metabolism and key inflammatory processes, and reduced their ability to produce TNFa, likely via an indirect mechanism. ButM treatment also reduced numbers of graft-infiltrating monocytes but not T cells. Consistent with its critical effect on myeloid cells, ButM's extension of graft survival depended on the presence of CCR2+ cells. These findings imply that cecal ButM improves distal allograft outcomes by quantitatively and qualitatively modulating myeloid cells, thereby inhibiting the innate immune cell-mediated effector phase of alloimmunity.

Ginsenoside RB1 Influences Macrophage-DPSC Interactions in Inflammatory Conditions

INTRODUCTION AND AIMS

Unresolved inflammation and tissue destruction are supposed to underlie the failure of dental pulp repair. As crucial regulators of the injury response, dental pulp stem cells (DPSCs) play a key role in pulp tissue repair and regeneration. M2 macrophages have been demonstrated to induce osteogenic/odontogenic differentiation of DPSCs. Ginsenoside Rb1 (GRb1) is the major component of ginseng and manifested an anti-inflammatory role by promoting M1 macrophage polarised into M2 macrophage in inflammatory disease. However, whether GRb1 facilitates odontogenic differentiation of DPSCs via promoting M2 macrophage polarisation under inflammatory conditions has yet to be established.

METHODS

Human monocyte leukemic cells (THP-1) differentiated macrophages were induced into M1 subsets and then treated with GRb1. After that, the conditioned medium was added to DPSCs. The cell co-cultured system was then subjected to odontogenic differentiation in osteogenic media. Effects of GRb1 on human dental pulp stem cells' (hDPSCs') osteogenic/odontogenic differentiation under inflammatory conditions were assessed by alkaline phosphatase (ALP) staining, Alizarin Red S (ARS) staining, and quantitative polymerase chain reaction testing.

RESULTS

Results demonstrated that GRb1 could facilitate the polarisation of macrophages from the M1 subtype to the M2 subtype. Conditioned medium from GRb1 + M1 macrophages, in comparison with M1 macrophages, may markedly increase the gene expression of ALP, DSPP, and DMP1. Moreover, ALP and ARS staining uncovered that the osteogenic/odontogenic differentiation ability of hDPSCs was strengthened in the M1 + GRb1 co-culture group.

CONCLUSIONS

GRb1 plays a crucial role in the inflammatory response and reparative dentine formation after dental pulp injury. Findings show that GRb1 modulates the interaction between macrophages and DPSCs during inflammation. The current study discusses modifications of deep caries therapy.

Peripheral Blood Monocytes as Biomarkers of Neurodevelopmental Disorders: A Systematic Review and Meta-Analysis

Accumulating evidence implicates immune dysregulation and chronic inflammation in neurodevelopmental disorders (NDDs), often manifesting as abnormal alterations in peripheral blood immune cell levels. The mononuclear phagocyte system, including monocytes and microglia, has been increasingly recognized for its involvement in the pathogenesis of NDDs. However, due to inconsistent findings in the literature, whether monocytes can serve as a reliable biomarker for NDDs remains controversial. To address this issue, we conducted a systematic review and meta-analysis of studies examining monocyte counts in NDD individuals. A comprehensive search was conducted across PubMed, Web of Science, and Scopus databases. Variables extracted for analysis encompassed the author's name, year of study, sample size, patient's age, type of disease, mean, standard deviation of monocytes and sex ratio. A total of 2503 articles were found by searching the three databases. After removed duplicates and screening titles, abstracts, and full texts, 17 articles met the inclusion criteria, and 20 independent studies were included in the meta-analysis. The results indicated significantly increased monocyte counts in 5 type NDDs compared to Typical Development (TD) groups (g = 0.36, 95%CI [0.23, 0.49]). Subgroup analyses revealed no significant differences in monocyte counts across different NDD types, gender, or age. These findings suggest that aberrant alterations in monocyte counts are common in NDD cases, indicating their potential as biomarkers for these conditions. Future research should further investigate the role of monocyte in understanding the mechanisms, early detection, and clinical diagnosis of NDDs.

Fucoidan alginate and sulfated alginate microbeads induce distinct coagulation, inflammatory and fibrotic responses

This study investigates the host response to fucoidan alginate microbeads in comparison to sulfated alginate microbeads, which are relevant for immune protection in cell therapy. While sulfated alginate microbeads reduce fibrosis and inflammation, fucoidan, a kelp-derived polysaccharide rich in sulfate groups, has not been evaluated in this context. The study assesses surface reactivity to acute-phase proteins and cytokines using ex vivo human whole blood and plasma models. It also examines pericapsular overgrowth (PFO) in C57BL/6JRj mice, incorporating protein pattern mapping through LC-MS/MS proteomics. Fucoidan alginate microbeads activated complement and coagulation, while both fucoidan and sulfated alginate microbeads induced plasmin activity. Fucoidan alginate microbeads exhibited a distinct cytokine profile, characterized by high levels of MCP-1, IL-8, IFN-γ, and reduced levels of RANTES, Eotaxin, PDGF-BB, TGF-β isoforms, along with higher PFO. The balance between plasmin activity and coagulation emerged as a potential predictor of fibrosis resistance, favouring sulfated alginate microbeads. Explanted materials were enriched with both complement and coagulation activators (Complement C1q and C3, Factor 12, Kallikrein, HMW-kininogen) and inhibitors (C1-inhibitor, Factor H, Factor I). Fucoidan alginate microbeads predominantly enriched extracellular matrix factors (Fibrinogen, Collagen, TGF-β, Bmp), while sulfated alginate microbeads favoured ECM-degrading proteases (Metalloproteases and Cathepsins). This study reveals significant differences in host responses to fucoidan and sulfated alginate in microbeads. The plasmin activity to coagulation ratio is highlighted as a key indicator of fibrosis resistance. Additionally, the preferential enrichment of ECM-degrading proteases on the material surface post-implantation proved to be another crucial factor.

CEBPA as a potential hub gene for cutaneous inflammation in type 2 diabetes mellitus

BACKGROUND

The role of inflammation in the development of type 2 diabetes mellitus (T2DM) related skin complications necessitates further investigation. This study aims to explore the correlation between inflammation and cutaneous alterations in T2DM, enhancing comprehension of underlying mechanism involved.

METHODS

Utilizing bioinformatics, the GSE38396 and GSE92724 datasets were employed to identify differentially expressed genes (DEGs) and potential hub genes in T2DM-related skin inflammation. Subsequently, gene functional enrichment analysis was employed for functional annotation. Finally, we validated the regulatory impact of hub gene on inflammation during high glucose incubation using the in vitro model.

RESULTS

A comprehensive analysis identified 742 DEGs, including 9 hub genes and 4 potential biomarkers. Compared to the CON group, the expression of M2 macrophages was significantly upregulated in the T2DM group, while resting dendritic cells and eosinophils showed notable decreases, indicating a significant correlation with CEBPA. Furthermore, functional enrichment analysis revealed significant enrichment of DEGs in pathways linked to immunity and diabetes pathogenesis. Interestingly, overexpression of CEBPA demonstrated anti-inflammatory effects under hyperglycemic conditions, while silencing CEBPA expression appeared to worsen inflammation.

CONCLUSION

CEBPA emerges as a potential hub gene for skin inflammation in T2DM, shedding light on the underlying mechanisms of this condition.

Crosstalk between metabolism and epigenetics during macrophage polarization

Macrophage polarization is a dynamic process driven by a complex interplay of cytokine signaling, metabolism, and epigenetic modifications mediated by pathogens. Upon encountering specific environmental cues, monocytes differentiate into macrophages, adopting either a pro-inflammatory (M1) or anti-inflammatory (M2) phenotype, depending on the cytokines present. M1 macrophages are induced by interferon-gamma (IFN-γ) and are characterized by their reliance on glycolysis and their role in host defense. In contrast, M2 macrophages, stimulated by interleukin-4 (IL-4) and interleukin-13 (IL-13), favor oxidative phosphorylation and participate in tissue repair and anti-inflammatory responses. Metabolism is tightly linked to epigenetic regulation, because key metabolic intermediates such as acetyl-coenzyme A (CoA), α-ketoglutarate (α-KG), S-adenosylmethionine (SAM), and nicotinamide adenine dinucleotide (NAD+) serve as cofactors for chromatin-modifying enzymes, which in turn, directly influences histone acetylation, methylation, RNA/DNA methylation, and protein arginine methylation. These epigenetic modifications control gene expression by regulating chromatin accessibility, thereby modulating macrophage function and polarization. Histone acetylation generally promotes a more open chromatin structure conducive to gene activation, while histone methylation can either activate or repress gene expression depending on the specific residue and its methylation state. Crosstalk between histone modifications, such as acetylation and methylation, further fine-tunes macrophage phenotypes by regulating transcriptional networks in response to metabolic cues. While arginine methylation primarily functions in epigenetics by regulating gene expression through protein modifications, the degradation of methylated proteins releases arginine derivatives like asymmetric dimethylarginine (ADMA), which contribute directly to arginine metabolism-a key factor in macrophage polarization. This review explores the intricate relationships between metabolism and epigenetic regulation during macrophage polarization. A better understanding of this crosstalk will likely generate novel therapeutic insights for manipulating macrophage phenotypes during infections like tuberculosis and inflammatory diseases such as diabetes.

Progression of Kidney Fibrosis after Sepsis: Underestimated Role of Resident Macrophages and Recruited Monocytes

Sepsis is a life-threatening condition affecting, each year, an estimated 49 million people and causing 11 million deaths. Short-term mortality of sepsis was substantially reduced during the past decades and is still improving. Besides its short-term lethality, awareness regarding long-term consequences of sepsis is rising. Among all organs affected during sepsis, the kidney is the most vulnerable. Up to 40% of patients suffering from sepsis develop AKI, and sepsis is the leading cause of AKI among critically ill patients. Half of patients will recover from AKI during their stay; however, several studies have pointed out that those patients were at higher risk for the development of subsequent CKD. In patients suffering from transient AKI, a second injury was found to hasten kidney fibrogenesis. Taken together those findings challenge the concept of ad integrum recovery and strongly suggest maladaptive repair AKI, together with profound and durable alterations at the intraorgan level. Factors driving AKI to CKD after sepsis are poorly understood and could be of multiple origins. Kidney macrophages have pleiotropic roles in health and disease. After sepsis, a proportion of kidney macrophages undergoes pyroptosis in an "altruist" maneuver to recruit inflammatory cells. Empty niches are later colonized by circulating monocyte arising from bone marrow in a process called emergency myelopoiesis but also by expansion of resident cells. The role of monocytes and macrophages in the acute phase of sepsis is well described; however, their role in the resolution of inflammation is just beginning to be understood. In the present review, we will discuss the fate of kidney resident macrophages and recruited monocytes in sepsis-induced AKI. We will review the evidence linking changes in the immune landscape and maladaptive repair after sepsis. Finally, we will consider how targeting macrophage recruitment and polarization might influence sepsis long-term consequences.

HTLV-1 p13 Protein Hijacks Macrophage Polarization and Promotes T-Cell Recruitment

The human T-cell leukemia type-1 (HTLV-1) retrovirus establishes chronic life-long infection in a fraction of infected individuals associated with severe pathological conditions. Although the mechanism driving disease development is not fully understood, current evidence indicates the essential functions of viral regulatory proteins. Among these, the p13 protein has previously been shown to localize to the inner mitochondrial membrane in T cells, altering mitochondrial biology and T-cell function. While CD4+ T cells are the primary cell target of HTLV-1 infection, genomic viral DNA has also been detected in monocytes, macrophages, and dendritic cells, which orchestrate innate and adaptive immunity and play a critical role in protecting against virus-induce diseases by establishing the appropriate balance of pro and anti-inflammatory responses. Given the central role of mitochondria in monocyte differentiation, we investigated the effect of p13 in monocytes/macrophages and found that by localizing to mitochondria, p13 affects mitochondrial respiration. Moreover, we demonstrate that p13 expression affects macrophage polarization to favor the recruitment of CD4+ T cells, the primary target of the virus, potentially facilitating the spread of viral infection and the development of disease.

Tonic signaling in CAR-T therapy: the lever long enough to move the planet

Chimeric antigen receptor (CAR) T-cell therapy has shown remarkable efficacy in treating hematological malignancies and is expanding into other indications such as autoimmune diseases, fibrosis, aging and viral infection. However, clinical challenges persist in treating solid tumors, including physical barriers, tumor heterogeneity, poor in vivo persistence, and T-cell exhaustion, all of which hinder therapeutic efficacy. This review focuses on the critical role of tonic signaling in CAR-T therapy. Tonic signaling is a low-level constitutive signaling occurring in both natural and engineered antigen receptors without antigen stimulation. It plays a pivotal role in regulating immune cell homeostasis, exhaustion, persistence, and effector functions. The "Peak Theory" suggests an optimal level of tonic signaling for CAR-T function: while weak tonic signaling may result in poor proliferation and persistence, excessively strong signaling can cause T cell exhaustion. This review also summarizes the recent progress in mechanisms underlying the tonic signaling and strategies to fine-tune the CAR tonic signaling. By understanding and precisely modulating tonic signaling, the efficacy of CAR-T therapies can be further optimized, offering new avenues for treatment across a broader spectrum of diseases. These findings have implications beyond CAR-T cells, potentially impacting other engineered immune cell therapies such as CAR-NK and CAR-M.

Cell-based immunotherapy in oesophageal cancer

Oesophageal cancer (EC) is among the most common illnesses globally, and its prognosis is unfavourable. Surgery, radiotherapy and chemotherapy are the primary therapy options for EC. Despite the occasional efficacy of these traditional treatment modalities, individuals with EC remain at a significant risk for local recurrence and metastasis. Consequently, innovative and efficacious medicines are required. In recent decades, clinical practice has effectively implemented cell therapy, which includes both stem cell and non-stem cell-based approaches, as an innovative tumour treatment, offering renewed hope to patients with oesophageal squamous cell carcinoma (ESCC). This paper examines the theoretical framework and contemporary advancements in cell treatment for individuals with EC. We further described current clinical studies and summarised essential data related to survival and safety assessments.

Selinexor's Immunomodulatory Impact in Advancing Multiple Myeloma Treatment

Despite the major advancements in the repertoire for multiple myeloma (MM) treatment, this disease remains a chronically progressive plasma cell malignancy. Drug resistance and high relapse rates complicate the extended treatment strategies. However, the tumor microenvironment (TME) in MM is decisive for the success of a therapy or relapse. Aiming to improve the outcome of relapsed and refractory MM patients, Selinexor has entered the drug arsenal of myeloma therapy through the implementation of a novel therapeutic approach by selectively inhibiting the nuclear export receptor Exportin-1 (XPO1). Selinexor leads to the inactivation of cancer-related proteins and induces apoptosis by disrupting the nucleocytoplasmic flow in myeloma cells. While this drug is selectively cytotoxic to neoplastic cells, Selinexor's immunomodulatory impact on the TME is currently being investigated. The aim of this review was to elucidate Selinexor's capacity to influence the cell interaction network of the TME from an immunological perspective. Deciphering the complex interplay of highly plastic immune cells provides a contribution to the molecular-biological exploration of disease initiation and progression in MM. Unraveling the novel therapeutic targets of the immunological TME and evaluating the advanced immunotherapeutic regimens implementing Selinexor will shape the future directions of immune-oncotherapy in MM.

Modulatory Effects of the Recombinant Middle East Respiratory Syndrome Coronavirus (MERS-CoV) Spike S1 Subunit Protein on the Phenotype of Camel Monocyte-Derived Macrophages

Middle East Respiratory Syndrome Coronavirus (MERS-CoV) is an emerging zoonotic pathogen with different pathogenesis in humans and camels. The mechanisms behind the higher tolerance of camels to MERS-CoV infection are still unknown. Monocytes are innate myeloid cells that are able, depending on the local stimulation in their microenvironment, to differentiate into different functional subtypes of macrophages with an impact on the adaptive immune response. Several in vitro protocols have been used to induce the differentiation of monocyte-derived macrophages (MDMs) in human and several veterinary species. Such protocols are not available for camel species. In the present study, monocytes were separated from camel blood and differentiated in vitro in the presence of different stimuli into MDM. Camel MDMs generated in the presence of a combined stimulation of monocytes with LPS and GM-CSF resulted in the development of an M1 macrophages phenotype with increased abundance of the antigen-presentation receptor MHCII molecules and a decreased expression of the scavenger receptor CD163. The expression pattern of the cell markers CD163, CD14, CD172a, CD44, and CD9 on MDM generated in the presence of the MERS-CoV S1 protein revealed similarity with M-CSF-induced MDM, suggesting the potential of the MERS-CoV S1 protein to induce an M2 macrophages phenotype. Similarly to the effect of M-CSF, MERS-CoV-S protein-induced MDMs showed enhanced phagocytosis activity compared to non-polarized or LPS/GM-CSF-polarized MDMs. Collectively, our study represents the first report on the in vitro generation of monocyte-derived macrophages (MDMs) in camels and the characterization of some phenotypic and functional properties of camel MDM under the effect of M1 and M2 polarizing stimuli. In addition, the results suggest a polarizing effect of the MERS-CoV S1 protein on camel MDMs, developing an M2-like phenotype with enhanced phagocytosis activity. To understand the clinical relevance of these in vitro findings on disease pathogenesis and camel immune response toward MERS-CoV infection, further studies are required.

Immunomodulatory Properties of Sweet Whey-Derived Peptides in THP-1 Macrophages

Sweet whey (SW), a by-product of cheese production, has potential immunomodulatory properties that could be beneficial in preventing inflammation-related diseases. This study investigated the effects of SW derived from bovine, caprine, ovine, or an ovine/caprine mixture of milk on inflammation-related gene expression in THP-1-derived macrophages, both with and without LPS stimulation. Cells were treated with SW-D-P3 (a fraction smaller than 3 kDa produced by in vitro digestion), and the expression of inflammation-related genes was assessed using quantitative PCR. Results showed that the expression of TLR2 and ICAM1 was attenuated in non-LPS-stimulated macrophages treated with SW-D-P3, regardless of animal origin. Moreover, the expression of TLR4, IL1B, and IL6 was decreased and the expression of an NF-κB subunit RELA and CXCL8 was elevated in a subset of samples treated with SW-D-P3, depending on the milk source. In LPS-challenged cells, the expression of CXCL8 was upregulated and the expression of IRF5 and TNFRSF1A was downregulated in SW-D-P3-treated cells, regardless of animal origin. On the other hand, a number of inflammation-related genes were differentially expressed depending on the animal origin of the samples. Moreover, the higher IL10 expression observed in cells treated with ovine/caprine SW-D-P3 compared to those treated with SW-D-P3 of bovine, caprine, or ovine origin suggests an anti-inflammatory response, in which alternatively activated macrophages (M2 polarization phenotype) may participate. Overall, these findings suggest that incorporating SW into the food industry, either as a standalone ingredient or supplement, may help to prevent inflammation-related diseases.

Cross-Talk Between Cancer and Its Cellular Environment-A Role in Cancer Progression

The tumor microenvironment is a dynamic and complex three-dimensional network comprising the extracellular matrix and diverse non-cancerous cells, including fibroblasts, adipocytes, endothelial cells and various immune cells (lymphocytes T and B, NK cells, dendritic cells, monocytes/macrophages, myeloid-derived suppressor cells, and innate lymphoid cells). A constantly and rapidly growing number of studies highlight the critical role of these cells in shaping cancer survival, metastatic potential and therapy resistance. This review provides a synthesis of current knowledge on the modulating role of the cellular microenvironment in cancer progression and response to treatment.

Interleukin-27-polarized HIV-resistant M2 macrophages are a novel subtype of macrophages that express distinct antiviral gene profiles in individual cells: implication for the antiviral effect via different mechanisms in the individual cell-dependent manner

Introduction

Interleukin (IL)-27 is an anti-viral cytokine. IL-27-treated monocyte-derived macrophages (27-Mac) suppressed HIV replication. Macrophages are generally divided into two subtypes, M1 and M2 macrophages. M2 macrophages can be polarized into M2a, M2b, M2c, and M2d by various stimuli. IL-6 and adenosine induce M2d macrophages. Since IL-27 is a member of the IL-6 family of cytokines, 27-Mac was considered M2d macrophages. In the current study, we compared biological function and gene expression profiles between 27-Mac and M2d subtypes.

Methods

Monocytes derived from health donors were differentiated to M2 using macrophage colony-stimulating factor. Then, the resulting M2 was polarized into different subtypes using IL-27, IL-6, or BAY60-658 (an adenosine analog). HIV replication was monitored using a p24 antigen capture assay, and the production of reactive oxygen species (ROS) was determined using a Hydrogen Peroxide Assay. Phagocytosis assay was run using GFP-labeled opsonized E. coli. Cytokine production was detected by the IsoPlexis system, and the gene expression profiles were analyzed using single-cell RNA sequencing (scRNA-seq).

Results and Discussion

27-Mac and BAY60-658-polarized M2d (BAY-M2d) resisted HIV infection, but IL-6-polarized M2d (6-M2d) lacked the anti-viral effect. Although phagocytosis activity was comparable among the three macrophages, only 27-Mac, but neither 6-M2d nor BAY-M2d, enhanced the generation of ROS. The cytokine-producing profile of 27-Mac did not resemble that of the two subtypes. The scRNA-seq revealed that 27-Mac exhibited a different clustering pattern compared to other M2ds, and each 27-Mac expressed a distinct combination of anti-viral genes. Furthermore, 27-Mac did not express the biomarkers of M2a, M2b, and M2c. However, it significantly expressed CD38 (p<0.01) and secreted CXCL9 (p<0.001), which are biomarkers of M1.

Conclusions

These data suggest that 27-Mac may be classified as either an M1-like subtype or a novel subset of M2, which resists HIV infection mediated by a different mechanism in individual cells using different anti-viral gene products. Our results provide a new insight into the function of IL-27 and macrophages.

Advancement insights in cancer vaccines: mechanisms, types, and clinical applications

Immunotherapy can treat cancer by boosting the immune system to mark and destroy cancer cells. Cancer vaccine is a promising therapeutic strategy in immunotherapy. Cancer vaccines are divided into four groups according to different preparation techniques: cell-based vaccine, virus-based vaccine, peptide-based vaccine, and nucleic acid-based vaccine. Cancer vaccines can be given with traditional treatments or another immunotherapy to give better results and overcome tumor resistance. The cancer vaccine is a promising immunotherapy that could stimulate the immune response to kill cancer cells and create immune surveillance. However, much work is still needed to identify neoantigens, optimize the vaccination platform, and develop combination therapy to improve the efficacy of immunotherapy. This review highlights the mechanism of action of cancer vaccines, the main four groups of cancer vaccines regarding their development, research progress, and clinical applications, and how to assess immune response following cancer vaccination.

Periplocin improves the sensitivity of oxaliplatin-resistant hepatocellular carcinoma cells by inhibiting M2 macrophage polarization

The aim of this research was to investigate the impact of periplocin (PPLN) on oxaliplatin (OXA) resistance in hepatocellular carcinoma (HCC) cells and offer insights for improving clinical treatment of HCC. The IC50 value of HCC cell lines against OXA was detected by the CCK-8 assay, and an OXA-resistant HepG2 cell line (HepG2/OXA) was constructed. THP-1 cells were induced into M1 or M2 macrophages, and M2 macrophage-conditioned medium (M2-CM) was prepared. M1 and M2 macrophage polarization were detected using RT-qPCR and flow cytometry. CCK-8, EdU staining, clone formation assay, flow cytometry, and western blotting were used to assess the proliferation and apoptosis of HepG2/OXA cells treated with PPLN and M2-CM. Additionally, a nude mouse subcutaneous graft tumor model was constructed. PPLN enhanced the sensitivity of HepG2/OXA cells to OXA, reduced their clone-forming ability, and promoted their apoptosis. Notably, PPLN hindered M0 macrophage polarization to M2 macrophages, while M1 polarization remained unaffected. The proliferation-inhibiting and apoptosis-promoting effects of OXA+PPLN on HepG2/OXA cells were significantly attenuated by the addition of M2-CM, suggesting that PPLN improves the OXA sensitivity of HepG2/OXA cells by hindering M2 macrophage polarization. Furthermore, PPLN inhibited M2 macrophage polarization and improved the OXA sensitivity of HepG2/OXA cells in vivo. In conclusion, PPLN inhibited the proliferation of HepG2/OXA cells, promoted their apoptosis, and inhibited M2 macrophage polarization both in vivo and in vitro, which in turn enhanced the OXA sensitivity of HepG2/OXA cells.

The role of intestinal macrophage polarization in colitis-associated colon cancer

Chronic inflammation of the intestine is a significant risk factor in the development of colorectal cancer. The emergence of colitis and colorectal cancer is a complex, multifactorial process involving chronic inflammation, immune regulation, and tumor microenvironment remodeling. Macrophages represent one of the most prevalent cells in the colorectal cancer microenvironment and play a pivotal role in maintaining intestinal health and the development of colitis-associated colon cancer (CAC). Macrophages are activated mainly in two ways and resulted in three phenotypes: classically activated macrophages (M1), alternatively activated macrophages (M2). The most characteristic of these cells are the pro-inflammatory M1 and anti-inflammatory M2 types, which play different roles at different stages of the disease. During chronic inflammation progresses to cancer, the proportion of M2 macrophages gradually increases. The M2 macrophages secrete cytokines such as IL-10 and TGF-β, which promote angiogenesis and matrix remodeling, and create the favorable conditions for cancer cell proliferation, infiltration, and migration. Therefore, macrophage polarization has a dual effect on the progression of colitis to CAC. The combination of immunotherapy with reprogrammed macrophages and anti-tumor drugs may provide an effective means for enhancing the therapeutic effect. It may represent a promising avenue for developing novel treatments for CAC. In this review, we focus on the process of intestinal macrophage polarization in CAC and the role of intestinal macrophage polarization in the progression of colitis to colon cancer, and review the immunotherapy targets and relevant drugs targeting macrophages in CAC.

Material-Mediated Immunotherapy to Regulate Bone Aging and Promote Bone Repair

As the global population ages, an increasing number of elderly people are experiencing weakened bone regenerative capabilities, resulting in slower bone repair processes and associated risks of various complications. This review outlines the research progress on biomaterials that promote bone repair through immunotherapy. This review examines how manufacturing technologies such as 3D printing, electrospinning, and microfluidic technology contribute to enhancing the therapeutic effects of these biomaterials. Following this, it provides detailed introductions to various anti-osteoporosis drug delivery systems, such as injectable hydrogels, nanoparticles, and engineered exosomes, as well as bone tissue engineering materials and coatings used in immunomodulation. Moreover, it critically analyzes the current limitations of biomaterial-mediated bone immunotherapy and explores future research directions for material-mediated bone immunotherapy. This review aims to inspire new approaches and broaden perspectives in addressing the challenges of bone repair and aging by exploring innovative biomaterial-mediated immunotherapy strategies.

Alterations in murine macrophage reactivity and bactericidal efficacy following exposure to an environmentally relevant mixture of organochlorine pesticide compounds

While there are a number of factors which may promote chronic inflammation, a major factor is pro-inflammatory activation of resident and infiltrating macrophages. Recently, exposures to persistent organic pollutants including organochlorine (OC) pesticides have been implicated in dysregulation of macrophage function. However, the majority of these studies examined single compound effects and not mixture-based effects. To this end, the present study investigated the effects of an environmentally relevant mixture of three prevalent OC pesticide compounds on macrophage function. Briefly, J77A.1 macrophages were exposed to a mixture of dichlorodiphenyldichloroethylene, trans-nonachlor, and oxychlordane (DTO; 0.2-20 μM) for 24 h then effects on cell viability, caspase 3/7 activity, reactive oxygen species (ROS), mitochondrial membrane potential (MMP), antibacterial activity, and pro-inflammatory cytokine production were determined. Exposure to DTO significantly increased caspase activity and ROS production. The highest concentration of DTO significantly increased Staphylococcus aureus uptake while decreasing phagolysosome formation and bactericidal efficacy. Lastly, exposure to DTO significantly increased basal production of Mcp-1. Taken together, the present study demonstrates an environmentally relevant mixture of OC pesticide compounds increases macrophage ROS and Mcp-1 production while decreasing macrophage bactericidal efficacy which may adversely affect macrophage function and increase susceptibility to S. aureus infection.

Identification of a novel cuproptosis inducer that induces ER stress and oxidative stress to trigger immunogenic cell death in tumors

Cuproptosis, a copper-dependent form of regulated cell death, has been implicated in the progression and treatment of various tumors. The copper ionophores, such as Disulfiram (DSF), an FDA-approved drug previously used to treat alcohol dependence, have been found to induce cuproptosis. However, the limited solubility and effectiveness of the combination of DSF and copper ion restrict its widespread application. In this study, through a random screening of our in-house compound library, we identified a novel cuproptosis inducer, YL21, comprising a naphthoquinone core substituted by two dithiocarbamate groups. The combination of YL21 with copper ion induces cuproptosis by disrupting mitochondrial function and promoting the oligomerization of lipoylated protein DLAT. Further, this combination induces endoplasmic reticulum (ER) stress and oxidative stress, triggering immunogenic cell death (ICD) and subsequently promoting the activation of antitumor immune responses to suppress tumor growth in the mice breast cancer model. Notably, the combination of YL21 and copper ion demonstrated improved solubility and increased antitumor activity compared to the combination of DSF and copper ion. Thus, YL21 functions as a novel cuproptosis inducer and may serve as a promising candidate for antitumor immunotherapy.

Radiation-induced rescue effect on human breast carcinoma cells is regulated by macrophages

The susceptibility of cancer cells to DNA damages is influenced by their microenvironment. For example, unirradiated neighbors of irradiated cells can produce signals that reduce DNA damages. This phenomenon, known as Radiation-Induced Rescue Effect (RIRE), has profound implications on the efficacy of radiotherapy. Using bystander cells co-cultured with mock-irradiated cells as a control, we demonstrated, for the first time, two types of RIRE. Conditioned medium from naïve by stander cells, i.e., cells not exposed to irradiated cells, could mitigate UV-induced DNA damages in human breast carcinoma MCF7 cells, as judged by phospho-H2AX and 53BP1 immunostaining. This protective effect could be further enhanced by the prior treatment of bystander cells with factors from UV-irradiated cells. We named the former effect "basal RIRE" and the latter "active RIRE" which were cell type-dependent. As bystanders, MCF7 showed a significant active RIRE, whereas THP1-derived macrophages showed a strong basal RIRE but no active RIRE. Interestingly, RIRE of macrophages could further be modulated by polarisation. The basal RIRE of macrophages was abolished by M1 polarisation, while M2 and Tumour Associated Macrophages (TAM) demonstrated pronounced basal and active RIRE. When mixtures of MCF7 cells and polarised macrophages were used as bystanders, the overall RIRE was dictated by macrophage phenotypes: RIRE was suppressed by M1 macrophages but significantly enhanced by M2 and TAM. This study shows a previously unappreciated role of the innate immune system in RIRE. Depending on polarised phenotypes, macrophages in the tumour microenvironment can interfere with the effectiveness of radiotherapy by adjusting the RIRE magnitudes.