Blood monocyte-derived CD169+ macrophages contribute to antitumor immunity against glioblastoma

Gut dysbiosis from high-salt diet promotes glioma via propionate-mediated TGF-β activation

The purpose of this study is to investigate the impact of a high-salt diet (HSD), which is commonly found in Western countries, on the progression of glioma. Our research shows that the alterations in gut microbiota caused by an HSD facilitated the development of glioma. Mice fed an HSD have elevated levels of intestinal propionate, which accelerated the growth of glioma cells. We also find that propionate supplementation enhanced the response of glioma cells to low oxygen levels. Moreover, we identify a link between TGF-β signaling, response to low oxygen levels, and invasion-related pathways. Propionate treatment increases the expression of HIF-1α, leading to an increase in TGF-β1 production. Additionally, propionate treatment promotes glioma cell invasion through TGF-β signaling. Our findings suggest that an HSD-induced increase in propionate plays a crucial role in glioma progression by facilitating invasion through the hypoxic response and TGF-β signaling pathways, thereby establishing a significant connection between gut microbiota and the progression of glioma.

Potential targets for synergistic bipolar irreversible electroporation in tumor suppression through transcriptomics and proteomics analysis

Previous studies have demonstrated that synergistic bipolar irreversible electroporation (SBIRE) is a promising non-thermal tumor ablation technique that effectively targets tumors without causing muscle contractions. Despite its clinical potential, the mechanistic understanding of SBIRE's tumor-suppressive effects remains underexplored. This study aims to identify potential molecular targets for SBIRE-mediated tumor suppression through comprehensive transcriptomics and proteomics analyses. Mice were selected as subjects for the creation of tumor models by the subcutaneous tumor-bearing method. Following the SBIRE intervention, tumor surveillance and pathological investigations were carried out. A comprehensive investigation was conducted using RNA sequencing-based transcriptomics and label-free quantitative proteomics to examine normal and SBIRE treated tumor samples. Differentially expressed genes (DEGs) and crucial signaling pathways were found using bioinformatics analysis. Western blot (WB), immunohistochemistry (IHC), and quantitative real-time PCR (qRT-PCR) were used to validate potentially associated genes. The results demonstrate that a substantial reduction in tumor size was achieved following SBIRE treatment. A total of 86 genes exhibited differential expression in tumors, with 84 genes showing upregulation and 2 genes showing downregulation. According to bioinformatics research, these DEGs were involved in a wide variety of biological activities, such as cell adhesion, positive regulation of tumor necrosis factor production, and immune system process. Beside major enrichment pathways like Efferocytosis, Endocytosis, PPAR signaling pathway and Metabolic pathways. The upregulation of WDFY family member 4 (WDFY4), Thrombospondin 1(THBS1), Pentraxin 3 (PTX3), Superoxide dismutase 3 (SOD3) and Glutathione peroxidase 3 (GPX3) genes were confirmed. These insights into the molecular underpinnings of SBIRE offer a novel therapeutic strategy for enhancing tumor suppression and improving clinical outcomes in cancer treatment.

Tumor-associated macrophages remodel the suppressive tumor immune microenvironment and targeted therapy for immunotherapy

Despite the significant advances in the development of immune checkpoint inhibitors (ICI), primary and acquired ICI resistance remains the primary impediment to effective cancer immunotherapy. Residing in the tumor microenvironment (TME), tumor-associated macrophages (TAMs) play a pivotal role in tumor progression by regulating diverse signaling pathways. Notably, accumulating evidence has confirmed that TAMs interplay with various cellular components within the TME directly or indirectly to maintain the dynamic balance of the M1/M2 ratio and shape an immunosuppressive TME, consequently conferring immune evasion and immunotherapy tolerance. Detailed investigation of the communication network around TAMs could provide potential molecular targets and optimize ICI therapies. In this review, we systematically summarize the latest advances in understanding the origin and functional plasticity of TAMs, with a focus on the key signaling pathways driving macrophage polarization and the diverse stimuli that regulate this dynamic process. Moreover, we elaborate on the intricate interplay between TAMs and other cellular constituents within the TME, that is driving tumor initiation, progression and immune evasion, exploring novel targets for cancer immunotherapy. We further discuss current challenges and future research directions, emphasizing the need to decode TAM-TME interactions and translate preclinical findings into clinical breakthroughs. In conclusion, while TAM-targeted therapies hold significant promise for enhancing immunotherapy outcomes, addressing key challenges-such as TAM heterogeneity, context-dependent plasticity, and therapeutic resistance-remains critical to achieving optimal clinical efficacy.

Sialic Acids: Sweet modulators fueling cancer cells and domesticating the tumor microenvironment

Tumor microenvironment (TME) can shift towards either immune activation or immunosuppression, influenced by various factors. Recent studies have underscored the pivotal role of sialic acids, a group of monosaccharides with a 9-carbon backbone, in modulating the TME. Aberrant expression or abnormal addition of sialic acids to the surface of cancer cells and within the tumor stroma has been identified as a key contributor to tumor progression. Abnormal sialylation on cancer cell surfaces can inhibit apoptosis, enhance cell proliferation, and facilitate metastasis. Notably, recent findings suggest that dysregulated sialic acid expression in the TME actively contributes to shaping an immunosuppressive niche by reducing the population of anti-tumor immune cells and impairing immune cell function. The mechanisms by which sialic acids foster immune escape and shape the immunosuppressive TME have been partially unraveled, particularly through interactions with sialic acid receptors on immune cells. Importantly, several sialic acid-targeted therapies are currently advancing into clinical trials, offering promising prospects for clinical translation. This dysregulated sialylation represents a significant opportunity for molecular diagnostics and therapeutic interventions in oncology. Targeting aberrant sialylation or disrupting the interaction between sialic acids and their receptors offers potential strategies to reprogram the TME towards an anti-tumor phenotype, thereby facilitating the advancement of innovative cancer therapies.

Immunomodulatory mechanisms driving tumor escape in glioblastoma: The central role of IDO and tryptophan metabolism in local and systemic immunotolerance

BACKGROUND

Glioblastoma (GBM) is the most aggressive primary brain tumor exhibiting extensive immune evasion mechanisms that hinder effective therapeutic interventions. This narrative review explores the immunomodulatory pathways contributing to tumor escape in GBM, specifically focusing on the role of Tryptophan (TRP) metabolism and its downstream mediators Tryptophan metabolism through the kynurenine pathway (KP) is initiated by indoleamine 2,3-dioxygenase (IDO) and tryptophan-2,3-dioxygenase (TDO2) enzymes and serves as a crucial mechanism for promoting an immunosuppressive microenvironments and systemic immunotolerance. Emerging evidence also indicates a non-enzymatic role for IDO1 signaling in these processes. The downstream effectors interact with immune cells, inducing local immunosuppression within the tumor microenvironment and altering peripheral immune responses.

METHODS

We systematically reviewed databases (MEDLINE via PubMed, Science Direct, and Embase) through October 2024 to highlight the interplay between local immune escape mechanisms and circulating immunotolerance, emphasizing the role of TRP metabolic enzymes in supporting GBM progression.

RESULTS

The literature review identified 99 records. TRP-related mechanisms play a central role in fostering immunotolerance in GBM. These phenomena involve intricate interactions between the infiltrating and circulating myeloid and lymphoid compartments, ultimately shaping a tolerant, pro-tumoral environment and the peripheral immunophenotype.

CONCLUSIONS

The biological activity of IDO1 and TRP metabolites positions these compounds as potential markers of disease activity and promising molecular targets for future therapeutic approaches.

YTHDC2 manipulates anti-tumoral macrophage polarization and predicts favorable outcomes in triple negative breast cancer

Triple-negative breast cancer (TNBC) possesses high malignant and metastatic rates among all subtypes. Chemotherapy is a standard of care for TNBC but only a small moiety of patients achieved complete relief (CR) after chemotherapy. The recent concept of tumor ecosystem has provided new insights into solutions from an approach of enhancing anti-tumoral immunity of macrophages. We hereby observed a positive correlation of YTHDC2 abundance with anti-tumoral gene markers of macrophages. YTHDC2-high macrophages also exerted interactions with other immune cells such as T helper cells, cytotoxic T cells, and NK cells. Further investigation on the transcriptional regulatory network identified six transcriptional factors upregulated by YTHDC2, and they together influenced the expressions of TWISTNB and the oncogene MYC. Additionally, our survival analysis prompted that YTHDC2 is prognostic of higher chemo-therapeutic efficacy and better survival outcomes. We demonstrated that ample macrophage YTHDC2 indicates anti-tumoral phenotype polarization and propitious survival outcome in post-treatment TNBC patients (Clinical trial registry name: Chinese Clinical Trial Registry, Registration No.: ChiCTR2400084513, Registration Date: 2024-05-20).

Huang-Lian-Jie-Du decoction alleviates cognitive deficits in Alzheimer's disease model 5xFAD mice by inhibiting Trem2/Dap12 signaling pathway

BACKGROUND

Alzheimer's disease (AD) is a progressive neurodegenerative disorder predominantly affecting the elderly population. It is characterized by cognitive deficits associated with the accumulation of amyloid-beta plaques and neurofibrillary tangles. Huang-Lian-Jie-Du (HLJD) decoction, recognized as a representative formulation with heat-clearing and detoxification effects, has been demonstrated to be effective in treating AD. However, the underlying mechanisms require further investigation.

METHODS

5xFAD mice were administrated low and high doses of HLJD. The Morris water maze test was conducted to assess the effects of HLJD. Aβ42 and total tau protein levels were evaluated. Additionally, network pharmacology analysis was performed to identify therapeutic targets of HLJD's active components and their relevance to AD. ELISA, qPCR, Western Blot, and immunofluorescence assays were employed to confirm the identified pathways. Finally, primary microglia isolated from 5xFAD mice were used to validate the candidate targets of HLJD.

RESULTS

HLJD improved cognitive deficits in 5xFAD mice and reduced amyloid plaque deposition and tau protein levels. Network pharmacology analysis indicated that HLJD influences the neuroinflammatory response, particularly through the Dap12 signaling pathway. This was confirmed by reduced levels of neuroinflammation markers, including TNF-α, IL-1β, IL-6, and indicators of microglial activation and polarization. The expression of Trem2 and Dap12 in the hippocampus (HIP) of 5xFAD mice, as well as in the isolated primary microglia, were downregulated following HLJD treatment.

CONCLUSION

Our study indicates that HLJD alleviates cognitive deficits in AD by suppressing the Trem2/Dap12 signaling pathway in the HIP of 5xFAD mice, thereby inhibiting microglial neuroinflammation.

Targeting ARPC1B Overcomes Immune Checkpoint Inhibitor Resistance in Glioblastoma by Reversing Protumorigenic Macrophage Polarization

Immunotherapy has elicited significant improvements in outcomes for patients with several tumor types. However, the immunosuppressive microenvironment in glioblastoma (GBM) restricts the therapeutic efficacy of immune checkpoint blockade (ICB). In this study, we investigated the components of the immune microenvironment that contribute to ICB failure in GBM to elucidate the underlying causes of immunotherapeutic resistance. Macrophages were identified as a main contributor to ICB resistance. Expression of actin-related protein 2/3 complex subunit 1B (ARPC1B), a regulatory subunit of the Arp2/3 complex, was elevated in GBM and correlated with macrophage enrichment and prognosis. ARPC1B in tumor cells increased STAT1 expression and subsequent IL10 production, which induced a protumorigenic macrophage state. Mechanistically, ARPC1B inhibited the ubiquitination and degradation of STAT1 by preventing the E3 ubiquitin ligase NEDD4L from binding to STAT1 and by supporting the interaction between STAT1 and the deubiquitinase USP7. Inhibiting ARPC1B reshaped the immunosuppressive microenvironment and increased the efficacy of ICB in GBM models. This study highlights the important role of ARPC1B in macrophage-mediated immunosuppression and proposes a combination treatment regimen for GBM immunotherapy. Significance: ARPC1B induces macrophage-mediated immunosuppression by activating a STAT1/IL10 axis and can be targeted to improve the efficacy of immune checkpoint blockade in glioblastoma.

Sialidase fusion protein protects against influenza infection in a cigarette smoke-induced model of COPD

First- and secondhand smokers are at an increased risk for influenza virus (IFV)-related respiratory failure and death. Despite approved influenza antiviral treatments, there is an unmet need for treatments that can improve outcomes in populations at risk for respiratory failure, including tobacco users with Chronic Obstructive Pulmonary Disease (COPD). Here we show that the sialidase fusion protein, DAS181, reduced viral burden, mitigated inflammation, and attenuated lung function loss, consistent with broad-spectrum anti-influenza responses in a mouse model of COPD and IFV-A infection. Treatment with DAS181 reprogramed the sialic acid-binding immunoglobulin-like lectins (Siglecs) in alveolar macrophages, increased expression of phagocytic marker CD169, and downregulated inhibitory Siglec-F and Siglec-H molecules. Upon reinfection, mice treated with DAS181 showed activated and protective memory response in the lungs. Collectively, we show that this sialidase fusion protein promotes a beneficial immunomodulatory reaction in the lungs, supporting a new IFV-A therapeutic option for at-risk smokers.

Opportunities to Modulate Tumor Ecosystem Toward Successful Glioblastoma Immunotherapy

Over the past decade, the failure of multiple clinical trials has confirmed the need for a systematic and comprehensive understanding of glioblastoma (GBM). Current immunotherapies aiming to harness the immune system to achieve anti-tumor effects remain largely ineffective, highlighting the complexities of the GBM microenvironment. However, our recent understanding of immune niches within the central nervous system provides both opportunities and challenges in translating these insights into successful immunotherapy implementation. We discuss these strategies, including targeting multiple antigens within the heterogeneous GBM microenvironment, identifying new druggable targets to abrogate immunosuppression, and understanding niche-specific immune cell functionality to modulate tumor-immune-stroma interactions.

Exploring CD169+ Macrophages as Key Targets for Vaccination and Therapeutic Interventions

CD169 is a sialic acid-binding immunoglobulin-like lectin (Siglec-1, sialoadhesin) that is expressed by subsets of tissue-resident macrophages and circulating monocytes. This receptor interacts with α2,3-linked Neu5Ac on glycoproteins as well as glycolipids present on the surface of immune cells and pathogens. CD169-expressing macrophages exert tissue-specific homeostatic functions, but they also have opposing effects on the immune response. CD169+ macrophages act as a pathogen filter, protect against infectious diseases, and enhance adaptive immunity, but at the same time pathogens also exploit them to enable further dissemination. In cancer, CD169+ macrophages in tumor-draining lymph nodes are correlated with better clinical outcomes. In inflammatory diseases, CD169 expression is upregulated on monocytes and on monocyte-derived macrophages and this correlates with the disease state. Given their role in promoting adaptive immunity, CD169+ macrophages are currently investigated as targets for vaccination strategies against cancer. In this review, we describe the studies investigating the importance of CD169 and CD169+ macrophages in several disease settings and the vaccination strategies currently under investigation.

The role of type I interferon signaling in myeloid anti-tumor immunity

Tumors often arise in chronically inflamed, and thus immunologically highly active niches. While immune cells are able to recognize and remove transformed cells, tumors eventually escape the control of the immune system by shaping their immediate microenvironment. In this context, macrophages are of major importance, as they initially exert anti-tumor functions before they adopt a tumor-associated phenotype that instead inhibits anti-tumor immune responses and even allows for sustaining a smoldering inflammatory, growth promoting tumor microenvironment (TME). Type I interferons (IFNs) are well established modulators of inflammatory reactions. While they have been shown to directly inhibit tumor growth, there is accumulating evidence that they also play an important role in altering immune cell functions within the TME. In the present review, we focus on the impact of type I IFNs on anti-tumor responses, driven by monocytes and macrophages. Specifically, we will provide an overview of tumor-intrinsic factors, which impinge on IFN-stimulated gene (ISG) expression, like the presence of nucleic acids, metabolites, or hypoxia. We will further summarize the current understanding of the consequences of altered IFN responses on macrophage phenotypes, i.e., differentiation, polarization, and functions. For the latter, we will focus on macrophage-mediated tumor cell killing and phagocytosis, as well as on how macrophages affect their environment by secreting cytokines and directly interacting with immune cells. Finally, we will discuss how type I IFN responses in macrophages might affect and should be considered for current and future tumor therapies.

Single-nucleus and spatial landscape of the sub-ventricular zone in human glioblastoma

The sub-ventricular zone (SVZ) is the most well-characterized neurogenic area in the mammalian brain. We previously showed that in 65% of patients with glioblastoma (GBM), the SVZ is a reservoir of cancer stem-like cells that contribute to treatment resistance and the emergence of recurrence. Here, we build a single-nucleus RNA-sequencing-based microenvironment landscape of the tumor mass and the SVZ of 15 patients and two histologically normal SVZ samples as controls. We identify a ZEB1-centered mesenchymal signature in the tumor cells of the SVZ. Moreover, the SVZ microenvironment is characterized by tumor-supportive microglia, which spatially coexist and establish crosstalks with tumor cells. Last, differential gene expression analyses, predictions of ligand-receptor and incoming/outgoing interactions, and functional assays reveal that the interleukin (IL)-1β/IL-1RAcP and Wnt-5a/Frizzled-3 pathways represent potential therapeutic targets in the SVZ. Our data provide insights into the biology of the SVZ in patients with GBM and identify potential targets of this microenvironment.

Metastatic brain tumors: from development to cutting-edge treatment

Metastatic brain tumors, also called brain metastasis (BM), represent a challenging complication of advanced tumors. Tumors that commonly metastasize to the brain include lung cancer and breast cancer. In recent years, the prognosis for BM patients has improved, and significant advancements have been made in both clinical and preclinical research. This review focuses on BM originating from lung cancer and breast cancer. We briefly overview the history and epidemiology of BM, as well as the current diagnostic and treatment paradigms. Additionally, we summarize multiomics evidence on the mechanisms of tumor occurrence and development in the era of artificial intelligence and discuss the role of the tumor microenvironment. Preclinically, we introduce the establishment of BM models, detailed molecular mechanisms, and cutting-edge treatment methods. BM is primarily treated with a comprehensive approach, including local treatments such as surgery and radiotherapy. For lung cancer, targeted therapy and immunotherapy have shown efficacy, while in breast cancer, monoclonal antibodies, tyrosine kinase inhibitors, and antibody-drug conjugates are effective in BM. Multiomics approaches assist in clinical diagnosis and treatment, revealing the complex mechanisms of BM. Moreover, preclinical agents often need to cross the blood-brain barrier to achieve high intracranial concentrations, including small-molecule inhibitors, nanoparticles, and peptide drugs. Addressing BM is imperative.

CD169+ Macrophages Mediate the Immune Response of Allergic Rhinitis Through the Keap1/Nrf2/HO-1 Axis

CD169+ macrophages are a newly defined macrophage subpopulation that can recognize and bind with other cells through related ligands, playing an essential role in antigen presentation and immune tolerance. However, its role in Allergic Rhinitis (AR) is still unclear. To investigate the characteristics of CD169+ macrophages in AR, this work first detects their expression patterns in the nasal mucosa of clinical patients. These results show a significant increase in CD169+ macrophages in the nasal mucosa of patients with AR. Subsequently, this work establishes an animal AR model using CD169 transgenic mice and compared the advantages of the two models. Moreover, this work also demonstrates the effects of CD169 knockout on eosinophils, Th cells, Treg cells, and the migration of dendritic cells (DCs). In addition, this metabolomic data shows that CD169+ macrophages can upregulate alanine production and increase reactive oxygen species (ROS) levels. This process may be mediated through the Keap1/Nrf2/HO-1 signaling pathway. In addition, this work also finds that SLC38A2 plays an essential role in the process of CD169+ macrophages promoting alanine uptake by DCs. This study confirms that CD169+ macrophages can upregulate their internal alanine production and increase ROS levels through the Keap1/Nrf2/HO-1 axis, playing an irreplaceable role in AR.

Unraveling Macrophage Polarization: Functions, Mechanisms, and "Double-Edged Sword" Roles in Host Antiviral Immune Responses

Numerous viruses that propagate through the respiratory tract may be initially engulfed by macrophages (Mφs) within the alveoli, where they complete their first replication cycle and subsequently infect the adjacent epithelial cells. This process can lead to significant pathological damage to tissues and organs, leading to various diseases. As essential components in host antiviral immune systems, Mφs can be polarized into pro-inflammatory M1 Mφs or anti-inflammatory M2 Mφs, a process involving multiple signaling pathways and molecular mechanisms that yield diverse phenotypic and functional features in response to various stimuli. In general, when infected by a virus, M1 macrophages secrete pro-inflammatory cytokines to play an antiviral role, while M2 macrophages play an anti-inflammatory role to promote the replication of the virus. However, recent studies have shown that some viruses may exhibit the opposite trend. Viruses have evolved various strategies to disrupt Mφ polarization for efficient replication and transmission. Notably, various factors, such as mechanical softness, the altered pH value of the endolysosomal system, and the homeostasis between M1/M2 Mφs populations, contribute to crucial events in the viral replication cycle. Here, we summarize the regulation of Mφ polarization, virus-induced alterations in Mφ polarization, and the antiviral mechanisms associated with these changes. Collectively, this review provides insights into recent advances regarding Mφ polarization in host antiviral immune responses, which will contribute to the development of precise prevention strategies as well as management approaches to disease incidence and transmission.

The two-sided battlefield of tumour-associated macrophages in glioblastoma: unravelling their therapeutic potential

Gliomas are the most common primary malignant tumours of the central nervous system (CNS), which are highly aggressive, with increasing morbidity and mortality rates year after year, posing a serious threat to the quality and expected survival time of patients. The treatment of gliomas is a major challenge in the field of neuro-oncology, especially high-grade gliomas such as glioblastomas (GBMs). Despite considerable progress in recent years in the study of the molecular and cellular mechanisms of GBMs, their prognosis remains bleak. Tumour-associated macrophages (TAMs) account for up to 50% of GBMs, and they are a highly heterogeneous cell population whose role cannot be ignored. Here, we focus on reviewing the contribution of classically activated M1-phenotype TAMs and alternatively activated M2-phenotype TAMs to GBMs, and exploring the research progress in reprogramming M1 TAMs into M2 TAMs.

Macrophages and tertiary lymphoid structures as indicators of prognosis and therapeutic response in cancer patients

Tertiary lymphoid structures (TLS) can reflect cancer prognosis and clinical outcomes in various tumour tissues. Tumour-associated macrophages (TAMs) are indispensable components of the tumour microenvironment and play crucial roles in tumour development and immunotherapy. TAMs are associated with TLS induction via the modulation of the T cell response, which is a major component of the TLS. Despite their important roles in cancer immunology, the subtypes of TAMs that influence TLS and their correlation with prognosis are not completely understood. Here, we provide novel insights into the role of TAMs in regulating TLS formation. Furthermore, we discuss the prognostic value of these TAM subtypes and TLS, as well as the current antitumour therapies for inducing TLS. This study highlights an entirely new field of TLS regulation that may lead to the development of an innovative perspective on immunotherapy for cancer treatment.

Phagocytosis Checkpoints in Glioblastoma: CD47 and Beyond

Glioblastoma multiforme (GBM) is one of the deadliest human cancers with very limited treatment options available. The malignant behavior of GBM is manifested in a tumor which is highly invasive, resistant to standard cytotoxic chemotherapy, and strongly immunosuppressive. Immune checkpoint inhibitors have recently been introduced in the clinic and have yielded promising results in certain cancers. GBM, however, is largely refractory to these treatments. The immune checkpoint CD47 has recently gained attention as a potential target for intervention as it conveys a "don't eat me" signal to tumor-associated macrophages (TAMs) via the inhibitory SIRP alpha protein. In preclinical models, the administration of anti-CD47 monoclonal antibodies has shown impressive results with GBM and other tumor models. Several well-characterized oncogenic pathways have recently been shown to regulate CD47 expression in GBM cells and glioma stem cells (GSCs) including Epidermal Growth Factor Receptor (EGFR) beta catenin. Other macrophage pathways involved in regulating phagocytosis including TREM2 and glycan binding proteins are discussed as well. Finally, chimeric antigen receptor macrophages (CAR-Ms) could be leveraged for greatly enhancing the phagocytosis of GBM and repolarization of the microenvironment in general. Here, we comprehensively review the mechanisms that regulate the macrophage phagocytosis of GBM cells.

Recent Advances in Nanoimmunotherapy by Modulating Tumor-Associated Macrophages for Cancer Therapy

Cancer immunotherapy has yielded remarkable results across a variety of tumor types. Nevertheless, the complex and immunosuppressive microenvironment within solid tumors poses significant challenges to established therapies such as immune checkpoint blockade (ICB) and chimeric antigen receptor T-cell (CAR-T) therapy. Within the milieu, tumor-associated macrophages (TAMs) play a significant role by directly suppressing T-cell functionality and fostering an immunosuppressive environment. Effective regulation of TAMs is, therefore, crucial to enhancing the efficacy of immunotherapies. Various therapeutic strategies targeting TAM modulation have emerged, including blocking TAM recruitment, direct elimination, promoting repolarization toward the M1 phenotype, and enhancing phagocytic capacity against tumor cells. The recently introduced CAR macrophage (CAR-M) therapy opens new possibilities for macrophage-based immunotherapy. Compared with CAR-T, CAR-M may demonstrate superior targeting and infiltration capabilities toward solid tumors. This review predominantly delves into the origin and development process of TAMs, their role in promoting tumor growth, and provides a comprehensive overview of immunotherapies targeting TAMs. It underscores the significance of regulating TAMs in bolstering antitumor therapies while discussing the potential and challenges of developing TAMs as targets for immunotherapy.

AS1411 binds to nucleolin via its parallel structure and disrupts the exos-miRNA-27a-mediated reciprocal activation loop between glioma and astrocytes

The interaction between glioma cells and astrocytes promotes the proliferation of gliomas. Micro-RNAs (miRNAs) carried by astrocyte exosomes (exos) may be involved in this process, but the mechanism remains unclear. The oligonucleotide AS1411, which consists of 26 bases and has a G-quadruplex structure, is an aptamer that targets nucleolin. In this study, we demonstrate exosome-miRNA-27a-mediated cross-activation between astrocytes and glioblastoma and show that AS1411 reduces astrocytes' pro-glioma activity. The enhanced affinity of AS1411 toward nucleolin is attributed to its G-quadruplex structure. After binding to nucleolin, AS1411 inhibits the entry of the NF-κB pathway transcription factor P65 into the nucleus, then downregulates the expression of miRNA-27a in astrocytes surrounding gliomas. Then, AS1411 downregulates astrocyte exosome-miRNA-27a and upregulates the expression of INPP4B, the target gene of miRNA-27a in gliomas, thereby inhibiting the PI3K/AKT pathway and inhibiting glioma proliferation. These results were verified in mouse orthotopic glioma xenografts and human glioma samples. In conclusion, the parallel structure of AS1411 allows it to bind to nucleolin and disrupt the exosome-miRNA-27a-mediated reciprocal activation loop between glioma cells and astrocytes. Our results may help in the development of a novel approach to therapeutic modulation of the glioma microenvironment.

CD169+ Skin Macrophages Function as a Specialized Subpopulation in Promoting Psoriasis-like Skin Disease in Mice

Skin macrophages are critical to maintain and restore skin homeostasis. They serve as major producers of cytokines and chemokines in the skin, participating in diverse biological processes such as wound healing and psoriasis. The heterogeneity and functional diversity of macrophage subpopulations endow them with multifaceted roles in psoriasis development. A distinct subpopulation of skin macrophages, characterized by high expression of CD169, has been reported to exist in both mouse and human skin. However, its role in psoriasis remains unknown. Here, we report that CD169+ macrophages exhibit increased abundance in imiquimod (IMQ) induced psoriasis-like skin lesions. Specific depletion of CD169+ macrophages in CD169-ditheria toxin receptor (CD169-DTR) mice inhibits IMQ-induced psoriasis, resulting in milder symptoms, diminished proinflammatory cytokine levels and reduced proportion of Th17 cells within the skin lesions. Furthermore, transcriptomic analysis uncovers enhanced activity in CD169+ macrophages when compared with CD169- macrophages, characterized by upregulated genes that are associated with cell activation and cell metabolism. Mechanistically, CD169+ macrophages isolated from IMQ-induced skin lesions produce more proinflammatory cytokines and exhibit enhanced ability to promote Th17 cell differentiation in vitro. Collectively, our findings highlight the crucial involvement of CD169+ macrophages in psoriasis development and offer novel insights into the heterogeneity of skin macrophages in the context of psoriasis.

Single-nucleus and spatial landscape of the sub-ventricular zone in human glioblastoma

The sub-ventricular zone (SVZ) is the most well-characterized neurogenic area in the mammalian brain. We previously showed that in 65% of patients with glioblastoma (GBM), the SVZ is a reservoir of cancer stem-like cells that contribute to treatment resistance and emergence of recurrence. Here, we built a single-nucleus RNA-sequencing-based microenvironment landscape of the tumor mass (T_Mass) and the SVZ (T_SVZ) of 15 GBM patients and 2 histologically normal SVZ (N_SVZ) samples as controls. We identified a mesenchymal signature in the T_SVZ of GBM patients: tumor cells from the T_SVZ relied on the ZEB1 regulatory network, whereas tumor cells in the T_Mass relied on the TEAD1 regulatory network. Moreover, the T_SVZ microenvironment was predominantly characterized by tumor-supportive microglia, which spatially co-exist and establish heterotypic interactions with tumor cells. Lastly, differential gene expression analyses, predictions of ligand-receptor and incoming/outgoing interactions, and functional assays revealed that the IL-1β/IL-1RAcP and Wnt-5a/Frizzled-3 pathways are therapeutic targets in the T_SVZ microenvironment. Our data provide insights into the biology of the SVZ in GBM patients and identify specific targets of this microenvironment.

CD169+ classical monocyte as an important participant in Graves' ophthalmopathy through CXCL12-CXCR4 axis

Patients with Graves' disease (GD) can develop Graves' ophthalmopathy (GO), but the underlying pathological mechanisms driving this development remain unclear. In our study, which included patients with GD and GO, we utilized single-cell RNA sequencing (scRNA-seq) and multiplatform analyses to investigate CD169+ classical monocytes, which secrete proinflammatory cytokines and are expanded through activated interferon signaling. We found that CD169+ clas_mono was clinically significant in predicting GO progression and prognosis, and differentiated into CD169+ macrophages that promote inflammation, adipogenesis, and fibrosis. Our murine model of early-stage GO showed that CD169+ classical monocytes accumulated in orbital tissue via the Cxcl12-Cxcr4 axis. Further studies are needed to investigate whether targeting circulating monocytes and the Cxcl12-Cxcr4 axis could alleviate GO progression.

Identification of prognostic risk score of disulfidptosis-related genes and molecular subtypes in glioma

Background

Programmed cell death is closely related to glioma. As a novel kind of cell death, the mechanism of disulfidptosis in glioma remains unclear. Therefore, it is of great importance to study the role of disulfidptosis-related genes (DRGs) in glioma.

Methods

We first investigated the genetic and transcriptional alterations of 15 DRGs. Two consensus cluster analyses were used to evaluate the association between DRGs and glioma subtypes. In addition, we constructed prognostic DRG risk scores to predict overall survival (OS) in glioma patients. Furthermore, we developed a nomogram to enhance the clinical utility of the DRG risk score. Finally, the expression levels of DRGs were verified by immunohistochemistry (IHC) staining.

Results

Most DRGs (14/15) were dysregulated in gliomas. The 15 DRGs were rarely mutated in gliomas, and only 50 of 987 samples (5.07 %) showed gene mutations. However, most of them had copy number variation (CNV) deletions or amplifications. Two distinct molecular subtypes were identified by cluster analysis, and DRG alterations were found to be related to the clinical characteristics, prognosis, and tumor immune microenvironment (TIME). The DRG risk score model based on 12 genes was developed and showed good performance in predicting OS. The nomogram confirmed that the risk score had a particularly strong influence on the prognosis of glioma. Furthermore, we discovered that low DRG scores, low tumor mutation burden, and immunosuppression were features of patients with better prognoses.

Conclusion

The DRG risk model can be used for the evaluation of clinical characteristics, prognosis prediction, and TIME estimation of glioma patients. These DRGs may be potential therapeutic targets in glioma.

Immunity in malignant brain tumors: Tumor entities, role of immunotherapy, and specific contribution of myeloid cells to the brain tumor microenvironment

Malignant brain tumors lack effective treatment, that can improve their poor overall survival achieved with standard of care. Advancement in different cancer treatments has shifted the focus in brain tumor research and clinical trials toward immunotherapy-based approaches. The investigation of the immune cell landscape revealed a dominance of myeloid cells in the tumor microenvironment. Their exact roles and functions are the subject of ongoing research. Current evidence suggests a complex interplay of tumor cells and myeloid cells with competing functions toward support vs. control of tumor growth. Here, we provide a brief overview of the three most abundant brain tumor entities: meningioma, glioma, and brain metastases. We also describe the field of ongoing immunotherapy trials and their results, including immune checkpoint inhibitors, vaccination studies, oncolytic viral therapy, and CAR-T cells. Finally, we summarize the phenotypes of microglia, monocyte-derived macrophages, border-associated macrophages, neutrophils, and potential novel therapy targets.

Roles of mechanosensitive ion channels in immune cells

Mechanosensitive ion channels are a class of membrane-integrated proteins that convert externalmechanical forces, including stretching, pressure, gravity, and osmotic pressure changes, some of which can be caused by pathogen invasion, into electrical and chemical signals transmitted to the cytoplasm. In recent years, with the identification of many of these channels, their roles in the initiation and progression of many diseases have been gradually revealed. Multiple studies have shown that mechanosensitive ion channels regulate the proliferation, activation, and inflammatory responses of immune cells by being expressed on the surface of immune cells and further responding to mechanical forces. Nonetheless, further clarification is required regarding the signaling pathways of immune-cell pattern-recognition receptors and on the impact of microenvironmental changes and mechanical forces on immune cells. This review summarizes the roles of mechanosensitive ion channels in immune cells.

Mechanisms and characteristics of subcapsular sinus macrophages in tumor immunity: a narrative review

Background and Objective

Lymph nodes constitute an integral component of the secondary lymphoid organs, housing a diverse population of macrophages. Macrophages exhibit heterogeneity in terms of localization, phenotype and ontogeny. Recent evidence has established that subcapsular sinus macrophages (SCSMs) are the initial cells exposed to antigens from afferent lymph vessels, playing a crucial role in the host immune response against invading pathogens and tumor cells. In order to summarize the role and mechanisms of SCSM in tumor immunity, this study systematically reviews research on SCSMs in tumor immunity.

Methods

A systematic search was conducted in PubMed and Web of Science to identify articles investigating clinical significance and mechanisms of SCSMs. Study eligibility was independently evaluated by two authors based on the assessment of titles, abstracts and full-texts.

Key Content and Findings

The narrative review included a total of 17 studies. Previous research consistently showed that a high level of SCSM in patients with various carcinomas is associated with a favorable long-term prognosis. SCSM acts as the front-line defender in antitumor activity, engaging in intricate communication with other immune cells. Moreover, SCSM could directly and indirectly modulate tumor immunity, and the integrity of SCSM layer is interrupted in disease status. Several studies explored the feasibility of targeting SCSM to activate immunity against tumors. However, the direct molecular interactions and alternation in signal pathway in the tumor immunity of SCSM are less well established in previous researches.

Conclusions

This narrative review underscores the critical role of SCSM in tumor immunity. Future studies should focus on the deeper mechanism underlying SCSMs and explore their clinical applications.

Cellular Components of the Tumor Environment in Gliomas-What Do We Know Today?

A generation ago, the molecular properties of tumor cells were the focus of scientific interest in oncology research. Since then, it has become increasingly apparent that the tumor environment (TEM), whose major components are non-neoplastic cell types, is also of utmost importance for our understanding of tumor growth, maintenance and resistance. In this review, we present the current knowledge concerning all cellular components within the TEM in gliomas, focusing on their molecular properties, expression patterns and influence on the biological behavior of gliomas. Insight into the TEM of gliomas has expanded considerably in recent years, including many aspects that previously received only marginal attention, such as the phenomenon of phagocytosis of glioma cells by macrophages and the role of the thyroid-stimulating hormone on glioma growth. We also discuss other topics such as the migration of lymphocytes into the tumor, phenotypic similarities between chemoresistant glioma cells and stem cells, and new clinical approaches with immunotherapies involving the cells of TEM.

Tumor macrophage functional heterogeneity can inform the development of novel cancer therapies

Macrophages represent a key component of the tumor microenvironment (TME) and are largely associated with poor prognosis. Therapeutic targeting of macrophages has historically focused on inhibiting their recruitment or reprogramming their phenotype from a protumor (M2-like) to an antitumor (M1-like) one. Unfortunately, this approach has not provided clinical breakthroughs that have changed practice. Emerging studies utilizing single-cell RNA-sequencing (scRNA-seq) and spatial transcriptomics have improved our understanding of the ontogeny, phenotype, and functional plasticity of macrophages. Overlaying the wealth of current information regarding macrophage molecular subtypes and functions has also identified novel therapeutic vulnerabilities that might drive better control of tumor-associated macrophages (TAMs). Here, we discuss the functional profiling of macrophages and provide an update of novel macrophage-targeted therapies in development.

Intercellular Molecular Crosstalk Networks within Invasive and Immunosuppressive Tumor Microenvironment Subtypes Associated with Clinical Outcomes in Four Cancer Types

Heterogeneity is a critical basis for understanding how the tumor microenvironment (TME) contributes to tumor progression. However, an understanding of the specific characteristics and functions of TME subtypes (subTMEs) in the progression of cancer is required for further investigations into single-cell resolutions. Here, we analyzed single-cell RNA sequencing data of 250 clinical samples with more than 200,000 cells analyzed in each cancer datum. Based on the construction of an intercellular infiltration model and unsupervised clustering analysis, four, three, three, and four subTMEs were revealed in breast, colorectal, esophageal, and pancreatic cancer, respectively. Among the subTMEs, the immune-suppressive subTME (subTME-IS) and matrix remodeling with malignant cells subTME (subTME-MRM) were highly enriched in tumors, whereas the immune cell infiltration subTME (subTME-ICI) and precancerous state of epithelial cells subTME (subTME-PSE) were less in tumors, compared with paracancerous tissues. We detected and compared genes encoding cytokines, chemokines, cytotoxic mediators, PD1, and PD-L1. The results showed that these genes were specifically overexpressed in different cell types, and, compared with normal tissues, they were upregulated in tumor-derived cells. In addition, compared with other subTMEs, the expression levels of PDCD1 and TGFB1 were higher in subTME-IS. The Cox proportional risk regression model was further constructed to identify possible prognostic markers in each subTME across four cancer types. Cell-cell interaction analysis revealed the distinguishing features in molecular pairs among different subTMEs. Notably, ligand-receptor gene pairs, including COL1A1-SDC1, COL6A2-SDC1, COL6A3-SDC1, and COL4A1-ITGA2 between stromal and tumor cells, associated with tumor invasion phenotypes, poor patient prognoses, and tumor advanced progression, were revealed in subTME-MRM. C5AR1-RPS19, LGALS9-HAVCR2, and SPP1-PTGER4 between macrophages and CD8+ T cells, associated with CD8+ T-cell dysfunction, immunosuppressive status, and tumor advanced progression, were revealed in subTME-IS. The spatial co-location information of cellular and molecular interactions was further verified by spatial transcriptome data from colorectal cancer clinical samples. Overall, our study revealed the heterogeneity within the TME, highlighting the potential pro-invasion and pro-immunosuppressive functions and cellular infiltration characteristics of specific subTMEs, and also identified the key cellular and molecular interactions that might be associated with the survival, invasion, immune escape, and classification of cancer patients across four cancer types.

The diversity and dynamics of tumor-associated macrophages in recurrent glioblastoma

Despite tremendous efforts to exploit effective therapeutic strategies, most glioblastoma (GBM) inevitably relapse and become resistant to therapies, including radiotherapy and immunotherapy. The tumor microenvironment (TME) of recurrent GBM (rGBM) is highly immunosuppressive, dominated by tumor-associated macrophages (TAMs). TAMs consist of tissue-resident microglia and monocyte-derived macrophages (MDMs), which are essential for favoring tumor growth, invasion, angiogenesis, immune suppression, and therapeutic resistance; however, restricted by the absence of potent methods, the heterogeneity and plasticity of TAMs in rGBM remain incompletely investigated. Recent application of single-cell technologies, such as single-cell RNA-sequencing has enabled us to decipher the unforeseen diversity and dynamics of TAMs and to identify new subsets of TAMs which regulate anti-tumor immunity. Here, we first review hallmarks of the TME, progress and challenges of immunotherapy, and the biology of TAMs in the context of rGBM, including their origins, categories, and functions. Next, from a single-cell perspective, we highlight recent findings regarding the distinctions between tissue-resident microglia and MDMs, the identification and characterization of specific TAM subsets, and the dynamic alterations of TAMs during tumor progression and treatment. Last, we briefly discuss the potential of TAM-targeted strategies for combination immunotherapy in rGBM. We anticipate the comprehensive understanding of the diversity and dynamics of TAMs in rGBM will shed light on further improvement of immunotherapeutic efficacy in rGBM.

Roles of the Siglec family in bone and bone homeostasis

Tremendous progress has been seen in the study of the role of sialic acid binding im-munoglobulin type lectins (Siglecs) in osteoimmunology in the past two decades. Interest in Siglecs as immune checkpoints has grown from the recognition that Siglecs have relevance to human disease. Siglecs play important roles in inflammation and cancer, and play key roles in immune cell signaling. By recognizing common sialic acid containing glycans on glycoproteins and glycolipids as regulatory receptors for immune cell signals, Siglecs are expressed on most immune cells and play important roles in normal homeostasis and self-tolerance. In this review, we describe the role that the siglec family plays in bone and bone homeostasis, including the regulation of osteoclast differentiation as well as recent advances in inflammation, cancer and osteoporosis. Particular emphasis is placed on the relevant functions of Siglecs in self-tolerance and as pattern recognition receptors in immune responses, thereby potentially providing emerging strategies for the treatment of bone related diseases.

Breast cancer associated CD169+ macrophages possess broad immunosuppressive functions but enhance antibody secretion by activated B cells

CD169⁺ resident macrophages in lymph nodes of breast cancer patients are for unknown reasons associated with a beneficial prognosis. This contrasts CD169⁺ macrophages present in primary breast tumors (CD169⁺ TAMs), that correlate with a worse prognosis. We recently showed that these CD169⁺ TAMs were associated with tertiary lymphoid structures (TLSs) and T_regs in breast cancer. Here, we show that CD169⁺ TAMs can be monocyte-derived and express a unique mediator profile characterized by type I IFNs, CXCL10, PGE₂ and inhibitory co-receptor expression pattern. The CD169⁺ monocyte-derived macrophages (CD169⁺ Mo-M) possessed an immunosuppressive function in vitro inhibiting NK, T and B cell proliferation, but enhanced antibody and IL6 secretion in activated B cells. Our findings indicate that CD169⁺ Mo-M in the primary breast tumor microenvironment are linked to both immunosuppression and TLS functions, with implications for future targeted Mo-M therapy.

Harnessing type I interferon-mediated immunity to target malignant brain tumors

Type I interferons have long been appreciated as a cytokine family that regulates antiviral immunity. Recently, their role in eliciting antitumor immune responses has gained increasing attention. Within the immunosuppressive tumor microenvironment (TME), interferons stimulate tumor-infiltrating lymphocytes to promote immune clearance and essentially reshape a "cold" TME into an immune-activating "hot" TME. In this review, we focus on gliomas, with an emphasis on malignant glioblastoma, as these brain tumors possess a highly invasive and heterogenous brain TME. We address how type I interferons regulate antitumor immune responses against malignant gliomas and reshape the overall immune landscape of the brain TME. Furthermore, we discuss how these findings can translate into future immunotherapies targeting brain tumors in general.

Tumor progression is independent of tumor-associated macrophages in cell lineage-based mouse models of glioblastoma

Macrophage targeting therapies have had limited clinical success in glioblastoma (GBM). Further understanding the GBM immune microenvironment is critical for refining immunotherapeutic approaches. Here, we use genetically engineered mouse models and orthotopic transplantation-based GBM models with identical driver mutations and unique cells of origin to examine the role of tumor cell lineage in shaping the immune microenvironment and response to tumor-associated macrophage (TAM) depletion therapy. We show that oligodendrocyte progenitor cell lineage-associated GBMs (Type 2) recruit more immune infiltrates and specifically monocyte-derived macrophages than subventricular zone neural stem cell-associated GBMs (Type 1). We then devise a TAM depletion system that offers a uniquely robust and sustained TAM depletion. We find that extensive TAM depletion in these cell lineage-based GBM models affords no survival benefit. Despite the lack of survival benefit of TAM depletion, we show that Type 1 and Type 2 GBMs have unique molecular responses to TAM depletion. In sum, we demonstrate that GBM cell lineage influences TAM ontogeny and abundance and molecular response to TAM depletion.

Boosting Glioblastoma Therapy with Targeted Pyroptosis Induction

Glioblastoma (GBM) is a highly aggressive cancer that currently lacks effective treatments. Pyroptosis has emerged as a promising therapeutic approach for cancer, but there is still a need for new pyroptosis boosters to target cancer cells. In this study, it is reported that Aloe-emodin (AE), a natural compound derived from plants, can inhibit GBM cells by inducing pyroptosis, making it a potential booster for pyroptosis-mediated GBM therapy. However, administering AE is challenging due to the blood-brain barrier (BBB) and its non-selectivity. To overcome this obstacle, AE@ZIF-8 NPs are developed, a biomineralized nanocarrier that releases AE in response to the tumor's acidic microenvironment (TAM). Further modification of the nanocarrier with transferrin (Tf) and polyethylene glycol-poly (lactic-co-glycolic acid) (PEG-PLGA) improves its penetration through the BBB and tumor targeting, respectively. The results show that AE-NPs (Tf-PEG-PLGA modified AE@ZIF-8 NPs) significantly increase the intracranial distribution and tumor tissue accumulation, enhancing GBM pyroptosis. Additionally, AE-NPs activate antitumor immunity and reduce AE-related toxicity. Overall, this study provides a new approach for GBM therapy and offers a nanocarrier that is capable of penetrating the BBB, targeting tumors, and attenuating toxicity.

The Role of Hypoxia in Brain Tumor Immune Responses

Oxygen is a vital component of living cells. Low levels of oxygen in body tissues, known as hypoxia, can affect multiple cellular functions across a variety of cell types and are a hallmark of brain tumors. In the tumor microenvironment, abnormal vasculature and enhanced oxygen consumption by tumor cells induce broad hypoxia that affects not only tumor cell characteristics but also the antitumor immune system. Although some immune reactions require hypoxia, hypoxia generally negatively affects immunity. Hypoxia induces tumor cell invasion, cellular adaptations to hypoxia, and tumor cell radioresistance. In addition, hypoxia limits the efficacy of immunotherapy and hinders antitumor responses. Therefore, understanding the role of hypoxia in the brain tumor, which usually does not respond to immunotherapy alone is important for the development of effective anti-tumor therapies. In this review, we discuss recent evidence supporting the role of hypoxia in the context of brain tumors.