Regulation of Human Macrophage M1-M2 Polarization Balance by Hypoxia and the Triggering Receptor Expressed on Myeloid Cells-1

Polarized macrophages modulate cardiac structure and contractility under hypoxia in novel immuno-heart on a chip

Cardiac adaptation to hypoxic injury is regulated by dynamic interactions between cardiomyocytes and macrophages, yet the impacts of immune phenotypes on cardiac structure and contractility remain poorly understood. To address this, we developed the immuno-heart on a chip, a novel in vitro platform to investigate cardiomyocyte-macrophage interactions under normoxic and hypoxic conditions. By integrating neonatal rat ventricular myocytes (NRVMs) and bone marrow-derived macrophages-polarized to pro-inflammatory (M1) or pro-healing (M2/M2*) phenotypes-we elucidated the dual protective and detrimental roles macrophages play in modulating cardiomyocyte cytoskeletal architecture and contractility. Pro-inflammatory stimulation reduced cardiomyocyte structural metrics (z-line length, fraction, and integrity) in normoxic co-cultures. Under hypoxia, M1-stimulated NRVM monocultures exhibited declines in cytoskeletal organization-quantified by actin and z-line orientational order parameters. Relative to monocultures, M1-stimulated co-cultures attenuated hypoxia-induced active stress declines but produced weaker normoxic stresses. In contrast, pro-healing stimulation improved normoxic z-line metrics and preserved post-hypoxia cytoskeletal organization but reduced normoxic contractility. Notably, M2-stimulated macrophages restored normoxic contractility and preserved post-hypoxia systolic stress, albeit with increased diastolic stress. RNAseq analysis of M2-stimulated co-cultures identified upregulated structural and immune pathways driving these hypoxia-induced changes. Cytokine profiles revealed stimulation-specific and density-dependent tumor necrosis factor-alpha and interleukin-10 secretion patterns. Together, these findings quantitatively link clinically relevant macrophage phenotypes and cytokines to distinct changes in cardiac structure and contractility, offering mechanistic insights into immune modulation of hypoxia-induced dysfunction. Moreover, the immuno-heart on a chip represents an innovative framework to guide the development of future therapies that integrate immune and cardiac targets to enhance patient outcomes.

Microenvironment-responsive coating for vascular stents to regulate coagulation-inflammation interaction and promote vascular recovery

Early coagulation-inflammation interaction and late in-stent restenosis undermine the efficacy of vascular stents after implantation. Targeting the interplay between inflammation and coagulation, and smooth muscle cell (SMC) proliferation, we presented a microenvironment-responsive coating designed to regulate tissue responses and vascular regeneration throughout the remodeling process. Coagulation was inhibited by incorporating anticoagulant tirofiban into the coating. MMP9-responsive nanoparticles embedded in the coating released salvianolic acid A to modulate inflammatory cell behavior and inhibit SMC dysfunction. By effectively interfering with clotting and inflammation, the coating suppressed platelet-fibrin interaction and formation of platelet-monocyte aggregates, thereby mitigating adverse effects on reendothelialization. Its ability to influence SMC proliferation and migration resulted in reduced intimal hyperplasia. Coated stents were shown to significantly regulate tissue regeneration, improve the vascular environment and even reduced the lipid content in the narrowed atherosclerotic vessels in vivo. This direct approach enhanced the vascular tissue regeneration after stent implantation, and offered promising insights for optimizing vascular stent design.

Estrogen induces the alternative activation of macrophages through binding to estrogen receptor-alpha

Age-related impaired wounds represent a major health burden resulting in considerable morbidity and mortality in the elderly. When injury occurs, monocytes migrate to the damaged site and undergo differentiation into tissue-resident macrophages, which are crucial for wound repair. For proper resolution of the inflammatory response, macrophages differentiate into two distinct phenotypes classified as classically-activatedpro-inflammatory and alternatively-activatedanti-inflammatory macrophages. Pro-inflammatory macrophages are commonly linked with pro-inflammatory events, while anti-inflammatory macrophages are known to be pro-regenerative. The age-related delay in wound repair is often attributed to the age-related decrease in local and systemic estrogen levels in both genders. However, despite its well-documented anti-inflammatory effect in wound healing, the role of estrogen and involvement of Estrogen Receptors (ERs) in macrophage polarization has gained little attention to date. To investigate the impact of estrogen and ERs on the polarization of macrophages, monocyte-derived macrophages were pre-treated with estrogen, ER-alpha agonist/antagonist or ER-beta agonist/antagonist prior to stimulation with LPS/IFN-γ or IL-4/IL-13 to produce pro-inflammatory or anti-inflammatory macrophages. Our findings confirm that estrogen promotes the alternative activation of macrophages via possible ER-α signalling. Selective targeting of ER-α with agents like PPT could potentially lead to the development of novel therapies to treat excessive inflammation in impaired wounds.

Polarized Macrophages Show Diverse Pro-Angiogenic Characteristics Under Normo- and Hyperglycemic Conditions

Angiogenesis plays a crucial role in solid tumor growth. Ischemia and inflammation induce various angiogenic mediators, and patient metabolic conditions importantly influence this process. Macrophages closely interact with the vascular system and regulate angiogenesis through pro/anti-angiogenic factors. Traditionally, pro-angiogenic activity has been attributed to M2-like macrophages. We question this, as recent evidence suggests that also M1-like macrophages can be pro-angiogenic. Therefore, the aim is to identify the pro/anti-angiogenic gene expression profiles of human polarized macrophages unbiasedly. We also examine the effect of hyperglycemia on angiogenic gene expression, reflecting its role in diabetes and other metabolic conditions. Bioinformatic analysis was performed on the angiogenesis-related gene expression profiles of CD14+ monocyte-derived M1(IFN-γ)- and M2(IL-4)-polarized macrophages. The top differentially expressed genes were selected for validation. Macrophages were generated in vitro and polarized to M1(IFN-γ) and M2(IL-4/IL-6) cells under standard/hyperglycemic conditions. After immunophenotypic confirmation, selected gene expression was quantified using qPCR. IL-4 and IL-6 induce distinct M2-like phenotypes with mixed pro/anti-angiogenic gene expression. Remarkably, IFN-γ stimulation also increases several pro-angiogenic genes. Hyperglycemia affects the angiogenic expression profile in both M1- and M2-like macrophages, although distinctive identities remain intact. The pro-angiogenic phenotype is not limited to M2-polarized macrophages. Both M1- and M2-like macrophages express complex pro/anti-angiogenic gene profiles, which are only mildly influenced by hyperglycemia.

Construction of a stromal cell-related prognostic signature based on a 101-combination machine learning framework for predicting prognosis and immunotherapy response in triple-negative breast cancer

Background

Triple-negative breast cancer (TNBC) is a highly aggressive subtype with limited therapeutic targets and poor immunotherapy outcomes. The tumor microenvironment (TME) plays a key role in cancer progression. Advances in single-cell transcriptomics have highlighted the impact of stromal cells on tumor progression, immune suppression, and immunotherapy. This study aims to identify stromal cell marker genes and develop a prognostic signature for predicting TNBC survival outcomes and immunotherapy response.

Methods

Single-cell RNA sequencing (scRNA-seq) datasets were retrieved from the Gene Expression Omnibus (GEO) database and annotated using known marker genes. Cell types preferentially distributed in TNBC were identified using odds ratios (OR). Bulk transcriptome data were analyzed using Weighted correlation network analysis (WGCNA) to identify myCAF-, VSMC-, and Pericyte-related genes (MVPRGs). A consensus MVP cell-related signature (MVPRS) was developed using 10 machine learning algorithms and 101 model combinations and validated in training and validation cohorts. Immune infiltration and immunotherapy response were assessed using CIBERSORT, ssGSEA, TIDE, IPS scores, and an independent cohort (GSE91061). FN1, a key gene in the model, was validated through qRT-PCR, immunohistochemistry, RNA interference, CCK-8 assay, apoptosis assay and wound-healing assay.

Results

In TNBC, three stromal cell subpopulations-myofibroblastic cancer-associated fibroblasts (myCAF), vascular smooth muscle cells (VSMCs), and pericytes-were enriched, exhibiting high interaction frequencies and strong associations with poor prognosis. A nine-gene prognostic model (MVPRS), developed from 23 prognostically significant genes among the 259 MVPRGs, demonstrated excellent predictive performance and was validated as an independent prognostic factor. A nomogram integrating MVPRS, age, stage, and tumor grade offered clinical utility. High-risk group showed reduced immune infiltration and increased activity in tumor-related pathways like ANGIOGENESIS and HYPOXIA, while low-risk groups responded better to immunotherapy based on TIDE and IPS scores. FN1, identified as a key oncogene, was highly expressed in TNBC tissues and cell lines, promoting proliferation and migration while inhibiting apoptosis.

Conclusion

This study reveals TNBC microenvironment heterogeneity and introduces a prognostic signature based on myCAF, VSMC, and Pericyte marker genes. MVPRS effectively predicts TNBC prognosis and immunotherapy response, providing guidance for personalized treatment. FN1 was validated as a key oncogene impacting TNBC progression and malignant phenotype, with potential as a therapeutic target.

Metabolic Reprogramming in Human Cancer Patients and Patient-Derived Models

Stable isotope-resolved metabolomics delineates reprogrammed intersecting metabolic networks in human cancers. Knowledge gained from in vivo patient studies provides the "benchmark" for cancer models to recapitulate. It is particularly difficult to model patients' tumor microenvironment (TME) with its complex cell-cell/cell-matrix interactions, which shapes metabolic reprogramming crucial to cancer development/drug resistance. Patient-derived organotypic tissue cultures (PD-OTCs) represent a unique model that retains an individual patient's TME. PD-OTCs of non-small-cell lung cancer better recapitulated the in vivo metabolic reprogramming of patient tumors than the patient-derived tumor xenograft (PDTX), while enabling interrogation of immunometabolic response to modulators and TME-dependent resistance development. Patient-derived organoids (PDOs) are also good models for reconstituting TME-dependent metabolic reprogramming and for evaluating therapeutic responses. Single-cell based 'omics on combinations of PD-OTC and PDO models will afford an unprecedented understanding on TME dependence of human cancer metabolic reprogramming, which should translate into the identification of novel metabolic targets for regulating TME interactions and drug resistance.

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.

Unraveling the triad of hypoxia, cancer cell stemness, and drug resistance

In the domain of addressing cancer resistance, challenges such as limited effectiveness and treatment resistance remain persistent. Hypoxia is a key feature of solid tumors and is strongly associated with poor prognosis in cancer patients. Another significant portion of the development of acquired drug resistance is attributed to tumor stemness. Cancer stem cells (CSCs), a small tumor cell subset with self-renewal and proliferative abilities, are crucial for tumor initiation, metastasis, and intra-tumoral heterogeneity. Studies have shown a significant association between hypoxia and CSCs in the context of tumor resistance. Recent studies reveal a strong link between hypoxia and tumor stemness, which together promote tumor survival and progression during treatment. This review elucidates the interplay between hypoxia and CSCs, as well as their correlation with resistance to therapeutic drugs. Targeting pivotal genes associated with hypoxia and stemness holds promise for the development of novel therapeutics to combat tumor resistance.

Acute hypoxia modulate macrophage phenotype accompanied with transcriptome re-programming and metabolic re-modeling

Introduction

Macrophages, which tend to aggregate in the hypoxic regions of tissues, have a significant impact on disease progression and outcome because of their plastic responsiveness to hypoxia, particularly in the early stages. Understanding macrophages'participation in hypoxia-related disorders requires demonstrating the impact of acute hypoxia on their survival, phenotype, and function.

Methods

Here we conducted a systematic evaluation of macrophage responses to hypoxia over 24 and 48 h including cell growth and activity, inflamatory response, macrophage polarization and transcriptional and metabolic changes.

Results

We found that acute hypoxia suppresses macrophage proliferation and phagocytosis function with a parallel change of transcriptome re-programming and metabolic re-modeling. Although macrophages accumulate transcriptome heterogeneity based on oxygen concentration and culture period, genes involved in hypoxia response, chemotaxis, and glycolytic process were commonly altered during acute hypoxia. Furthermore, the pro-inflammatory response of macrophages was activated during acute hypoxia concomitantly with an enhanced anti-inflammatory regulatory mechanism characterized by increased M2 macrophage population and anti-inflammatory metabolite itaconic acid. Aside from increased glycolysis, the key intermediates in the pentose phosphate pathway significantly increased, such as fructose 1,6-bisphosphate (fold change: 7.8), 6-phosphogluconate (fold change: 6.1), and ribose 5-phosphate (fold change: 3.9), which indicated that the pentose phosphate pathway was an important compensatory metabolic regulation that rules for the response of macrophages to acute hypoxia.

Discussion

These findings highlight that acute hypoxia suppresses macrophage viability and phagocytosis, while acute hypoxia modifies the transcriptome and metabolome in specific inflammatory responses and metabolic pathways to facilitate the adaptation of macrophage in hypoxic conditions.

Single-cell transcriptomics of bronchoalveolar lavage during PRRSV infection with different virulence

Porcine reproductive and respiratory syndrome virus (PRRSV) causes significant economic losses in the global swine industry due to its high genetic diversity and different virulence levels, which complicate disease management and vaccine development. This study evaluated longitudinal changes in the immune cell composition of bronchoalveolar lavage fluid and the clinical outcomes across PRRSV strains with varying virulence, using techniques including single-cell transcriptomics. In highly virulent infection, faster viral replication results in an earlier peak lung-damage time point, marked by significant interstitial pneumonia, a significant decrease in macrophages, and an influx of lymphocytes. Viral tracking reveals less than 5% of macrophages are directly infected, and further analysis indicates bystander cell death, likely regulated by exosomal microRNAs as a significant factor. In contrast, the peak intermediate infection shows a delayed lung-damage time point with fewer cell population modifications. Furthermore, anti-inflammatory M2-like macrophages (SPP1-CXCL14high) are identified and their counts increase during the peak lung-damage time point, likely contributing to local defense and lung recovery, which is not observed in high virulent infection. These findings provide a comprehensive description of the immune cellular landscape and differential PRRSV virulence mechanisms, which will help build new hypotheses to understand PRRSV pathogenesis and other respiratory infections.

Immunotherapy resistance in solid tumors: mechanisms and potential solutions

While the emergence of immunotherapies has fundamentally altered the management of solid tumors, cancers exploit many complex biological mechanisms that result in resistance to these agents. These encompass a broad range of cellular activities - from modification of traditional paradigms of immunity via antigen presentation and immunoregulation to metabolic modifications and manipulation of the tumor microenvironment. Intervening on these intricate processes may provide clinical benefit in patients with solid tumors by overcoming resistance to immunotherapies, which is why it has become an area of tremendous research interest with practice-changing implications. This review details the major ways cancers avoid both natural immunity and immunotherapies through primary (innate) and secondary (acquired) mechanisms of resistance, and it considers available and emerging therapeutic approaches to overcoming immunotherapy resistance.

Inosine Prevents Colorectal Cancer Progression by Inducing M1 Phenotypic Polarization of Macrophages

Inosine (IS) is a naturally occurring metabolite of adenosine with potent immunomodulatory effects. This study investigates the immunomodulatory effects of inosine, particularly its ability to inhibit the development of colorectal cancer (CRC) cells CT26 through modulation of macrophage phenotypes. Aside from the already reported effects of inosine on T cells, in this study, in vitro experiments revealed that inosine could modulate macrophage phenotype. The effects of inosine on the M1/M2 macrophage polarization were investigated at the cellular level. Its role in regulating CRC proliferation and migration was further examined. In addition, a CT26 tumor mouse model was established to assess the mechanism of action of inosine by tumor weight measurement, immunohistochemistry, and immunofluorescence. Inosine significantly increased M1 macrophage markers CD86 and iNOS and enhanced the anti-tumor activity of M1 macrophages, effectively inhibiting CRC progression and metastasis potential. In vivo, inosine had significant tumor inhibitory activity. It also significantly reduced the expression of Ki-67 and promoted the polarization of M1 macrophages.

Disrupting Notch signaling related HES1 in myeloid cells reinvigorates antitumor T cell responses

BACKGROUND

Tumor-associated macrophages (TAMs) are immunosuppressive cells within the tumor microenvironment (TME) that hinder anti-tumor immunity. Notch signaling is a pathway crucial for TAM differentiation and function. Here, we investigate the role of HES1, a downstream target of Notch signaling, in TAM-mediated immunosuppression and explore its potential as a target for cancer immunotherapy.

METHODS

In this work, we constructed conditional Hes1 knockout mice to selectively delete Hes1 in TAMs. We further analyzed the TME composition, T cell infiltration and activation, and anti-tumor effects in these mice, both alone and in combination with PD-1 checkpoint blockade.

RESULTS

Our study showed that expression levels of Notch target Hes1 were increase in TAMs and mice with conditional knockout of Hes1 gene in TAMs exhibited decreased tumor growth, with increased infiltration and activation of cytotoxic T cells in tumors. Expression of tumor promoting factors was critically altered in Hes1-conditional KO TAMs, leading to the improved tumor microenvironment. Notably, arginase-1 expression was decreased in Hes1-conditional KO mice. Arg1 is known to deplete arginine and deactivate T cells in the TME. Administration of anti-PD-1 monoclonal antibody inhibited tumor growth to a greater extent in Hes1-conditional KO mice than in WT mice.

CONCLUSIONS

We identified a pivotal role for the Notch signaling pathway in shaping TAM function, suggesting that T-cell dysfunction in the TME is caused when the Notch target, HES1, in TAMs is upregulated by tumor-associated factors (TAFs), which, in turn, increases the expression of arginase-1. Targeting HES1 in TAMs appears to be a promising strategy for cancer immunotherapy.

Xianglian pill alleviates ulcerative colitis by inhibiting M1 macrophage polarization via modulation of energy metabolite itaconate

BACKGROUND

Xianglian pill (XLP) is a traditional Chinese medicine (TCM) that is widely used to treat ulcerative colitis (UC). However, its mechanism of action in UC is unclear.

PURPOSE

This study aimed to investigate the mechanism of action of XLP in treating UC and role of M1 macrophage polarization in this process.

STUDY DESIGN

In vivo experiments were performed using UC mice while in vitro experiments were conducted using RAW264.7 cells.

METHODS

Mice were administered 3 % dextran sulfate to induce UC model and then treated with XLP. Changes in histopathology and pro-inflammatory cytokines were evaluated. The levels of M1 macrophages in mesenteric lymph nodes were detected by flow cytometry. Colon metabolite levels were analyzed using an energy metabolomic assay. To assess itaconate's impact, both in vivo (mice) and in vitro (RAW264.7 cells) models were employed. Immunofluorescence staining was used to measure the expression levels of TNF-α, IL-6, and iNOS, while qRT-PCR was utilized to quantify the mRNA levels of TET2, STAT1, and Nfkbiz.

RESULTS

XLP alleviated ulcerative damage and reduced TNF-α and IL-6 levels in colon, and also downregulated the levels of M1 macrophages and modulated the state of energy metabolism. Specifically, XLP significantly increased ITA level in colonic tissue and this increase was significantly associated with decreased levels of M1 macrophages and alleviation of UC following XLP treatment. Moreover, ITA directly suppressed the polarization of macrophage from M0 to M1 phenotype, accompanied by the decrease of TNF-α, IL-6, and iNOS levels. Further, ITA decreased inflammatory responses in M1 macrophage by inhibiting the TET2/STAT1 and TET2/NF-κB signaling pathways.

CONCLUSION

XLP can treat UC by suppressing M1 macrophage polarization via increasing the level of energy metabolite ITA.

How to Use Macrophages Against Cancer

Numerous studies have demonstrated the significant influence of immune cells on cancer development and treatment. This study specifically examines tumor-associated macrophages (TAMs), detailing their characteristics and roles in tumorigenesis and analyzing the impact of the ratio of TAM subtypes on patient survival and prognosis. It is established that TAMs interact with immunotherapy, radiotherapy, and chemotherapy, thereby influencing the efficacy of these treatments. Emerging therapies are explored, such as the use of nanoparticles (NPs) for drug delivery to target TAMs and modify the tumor microenvironment (TME). Additionally, novel anticancer strategies like the use of chimeric antigen receptor macrophages (CAR-Ms) show promising results. Investigations into the training of macrophages using magnetic fields, plasma stimulation, and electroporation are also discussed. Finally, this study presents prospects for the combination of TAM-based therapies for enhanced cancer treatment outcomes.

Taraxerone inhibits M1 polarization and alleviates sepsis-induced acute lung injury by activating SIRT1

BACKGROUND

Acute lung injury (ALI) is the most lethal disease associated with sepsis, and there is a lack of effective drug treatment. As the major cells of sepsis-induced ALI, macrophages polarize toward the proinflammatory M1 phenotype and secrete multiple inflammatory cytokines to accelerate the disease process through nuclear factor kappa-B (NF-κB) and NLR family pyrin domain containing 3 (NLRP3) inflammasome signaling pathways. Taraxerone, the main component of the Chinese medicinal Sedum, possesses numerous biological activities. However, uncertainty remains regarding the potential of taraxerone to protect against sepsis-induced ALI. This study aimed to investigate the effects and mechanisms of taraxerone against ALI.

METHODS

An animal model for ALI was established by cecal ligation and puncture and treated with taraxerone via intraperitoneal administration. The protective effect of taraxerone on the lungs was analyzed using H&E staining, dihydroethidium staining, ELISA kits, cell counting, myeloperoxidase kit, malondialdehyde kit, glutathione kit, superoxide dismutase kit and flow cytometry. Western blotting, RT-PCR, flow cytometry, co-immunoprecipitation, and immunofluorescence were used to investigate the regulatory of taraxerone on SIRT1.

RESULTS

Our study demonstrates for the first time that taraxerone can activate SIRT1 in macrophages, promoting SIRT1 activity. This activation inhibited the NF-κB signaling pathway primarily through the dephosphorylation and deacetylation of p65. Simultaneously, taraxerone disrupted the NLRP3 inflammasome signaling pathway, thereby alleviating M1 polarization of macrophages and mitigating sepsis-induced pulmonary inflammation and oxidative stress. In vivo, EX527 was used to validate the anti-inflammatory and anti-oxidative stress effects of taraxerone mediated by SIRT1.

CONCLUSION

SIRT1-mediated anti-inflammatory and anti-oxidative stress effects may be important targets for taraxerone in treating ALI.

Reprogramming of breast tumor-associated macrophages with modulation of arginine metabolism

HER2+ breast tumors have abundant immune-suppressive cells, including M2-type tumor-associated macrophages (TAMs). Although TAMs consist of the immune-stimulatory M1 type and immune-suppressive M2 type, the M1/M2-TAM ratio is reduced in immune-suppressive tumors, contributing to their immunotherapy refractoriness. M1- versus M2-TAM formation depends on differential arginine metabolism, where M1-TAMs convert arginine to nitric oxide (NO) and M2-TAMs convert arginine to polyamines (PAs). We hypothesize that such distinct arginine metabolism in M1- versus M2-TAMs is attributed to different availability of BH4 (NO synthase cofactor) and that its replenishment would reprogram M2-TAMs to M1-TAMs. Recently, we reported that sepiapterin (SEP), the endogenous BH4 precursor, elevates the expression of M1-TAM markers within HER2+ tumors. Here, we show that SEP restores BH4 levels in M2-like macrophages, which then redirects arginine metabolism to NO synthesis and converts M2 type to M1 type. The reprogrammed macrophages exhibit full-fledged capabilities of antigen presentation and induction of effector T cells to trigger immunogenic cell death of HER2+ cancer cells. This study substantiates the utility of SEP in the metabolic shift of the HER2+ breast tumor microenvironment as a novel immunotherapeutic strategy.

The potential of targeting TREM-1 in IBD

Innate immune dysfunction is a hallmark of the pathogenesis of Inflammatory Bowel Disease, both in Crohn's disease and ulcerative colitis. Despite considerable efforts in research to better understand the pathophysiology of IBD and for the development of new therapeutic modalities for IBD patients, there is no therapy specifically targeting the dysregulations of the innate immune response available today in that field. TREM-1 is exclusively expressed by innate immune cells and is an immune amplifier. Its engagement following the primary activation of Pattern Recognition Receptors, including Toll-Like Receptors, triggers the development of a dysregulated and sustained innate immune response, promoting the perpetuation of the inflammatory response in the mucosa of IBD patients, microscopic mucosal tissue alterations, impaired autophagy, impaired epithelial barrier integrity and function, ulcerations, and mucosal damages. In patients, TREM-1 activation is associated with the active status of the disease as well as with severity. Blocking TREM-1 in experimental colitis attenuates the dysregulated innate immune response leading to improved clinical signs. Anti-TREM-1 approaches have the potential of controlling the pathogenic dysregulation of the immune response in IBD by targeting an upstream amplification loop of the activation of innate immunity.

Inorganic Nanoparticle Functionalization Strategies in Immunotherapeutic Applications

Nanotechnology has been increasingly utilized in anticancer treatment owing to its ability of engineering functional nanocarriers that enhance therapeutic effectiveness while minimizing adverse effects. Inorganic nanoparticles (INPs) are prevalent nanocarriers to be customized for a wide range of anticancer applications, including theranostics, imaging, targeted drug delivery, and therapeutics, because they are advantageous for their superior biocompatibility, unique optical properties, and capacity of being modified via versatile surface functionalization strategies. In the past decades, the high adaptation of INPs in this emerging immunotherapeutic field makes them good carrier options for tumor immunotherapy and combination immunotherapy. Tumor immunotherapy requires targeted delivery of immunomodulating therapeutics to tumor locations or immunological organs to provoke immune cells and induce tumor-specific immune response while regulating immune homeostasis, particularly switching the tumor immunosuppressive microenvironment. This review explores various INP designs and formulations, and their employment in tumor immunotherapy and combination immunotherapy. We also introduce detailed demonstrations of utilizing surface engineering tactics to create multifunctional INPs. The generated INPs demonstrate the abilities of stimulating and enhancing the immune response, specific targeting, and regulating cancer cells, immune cells, and their resident microenvironment, sometimes along with imaging and tracking capabilities, implying their potential in multitasking immunotherapy. Furthermore, we discuss the promises of INP-based combination immunotherapy in tumor treatments.

Protocol to study the immune profile of syngeneic mouse tumor models

Flow cytometry, single-cell RNA sequencing, and other analyses enable us to capture immune profiles of the tumor microenvironment. Here, we present a protocol to characterize the immune profile of tumor-bearing mice. We describe steps for establishing mouse models and preparing single-cell suspensions from tumor tissue and other immune-related organs, which can be further analyzed by flow cytometry and other omics assays. We then detail procedures for staining, flow cytometry analysis, and phenotyping of the immune cell populations. For complete details on the use and execution of this protocol, please refer to Miyauchi et al.1.

Neu1 deficiency and fibrotic lymph node microenvironment lead to imbalance in M1/M2 macrophage polarization

Macrophages play a pivotal role in tissue homeostasis, pathogen defense, and inflammation resolution. M1 and M2 macrophage phenotypes represent two faces in a spectrum of responses to microenvironmental changes, crucial in both physiological and pathological conditions. Neuraminidase 1 (Neu1), a lysosomal and cell surface sialidase responsible for removing terminal sialic acid residues from glycoconjugates, modulates several macrophage functions, including phagocytosis and Toll-like receptor (TLR) signaling. Current evidence suggests that Neu1 expression influences M1/M2 macrophage phenotype alterations in the context of cardiovascular diseases, indicating a potential role for Neu1 in macrophage polarization. For this reason, we investigated the impact of Neu1 deficiency on macrophage polarization in vitro and in vivo. Using bone marrow-derived macrophages (BMDMs) and peritoneal macrophages from Neu1 knockout (Neu1-/- ) mice and wild-type (WT) littermate controls, we demonstrated that Neu1-deficient macrophages exhibit an aberrant M2-like phenotype, characterized by elevated macrophage mannose receptor 1 (MMR/CD206) expression and reduced responsiveness to M1 stimuli. This M2-like phenotype was also observed in vivo in peritoneal and splenic macrophages. However, lymph node (LN) macrophages from Neu1-/- mice exhibited phenotypic alterations with reduced CD206 expression. Further analysis revealed that peripheral LNs from Neu1-/- mice were highly fibrotic, with overexpression of transforming growth factor-beta 1 (TGF-β1) and hyperactivated TGF-β signaling in LN macrophages. Consistently, TGF-β1 was found to alter M1/M2 macrophage polarization in vitro. Our findings showed that Neu1 deficiency prompts macrophages towards an M2 phenotype and that microenvironmental changes, particularly increased TGF-β1 in fibrotic tissues such as peripheral LNs in Neu1-/- mice, further influence M1/M2 macrophage polarization, highlighting its sensitivity to the local microenvironment. Therapeutic interventions targeting Neu1 or TGF-β signaling pathways may offer the potential to regulate macrophage behavior across different diseases.

Does Eosinophil Heterogeneity Translate into Functional Diversity? A Review of the Evolving Paradigm of Eosinophil Heterogeneity in Asthma

This review provides an overview of evidence supporting the existence of distinct homeostatic and inflammatory eosinophil subpopulations in health and disease. Particular emphasis is placed on describing the phenotypic and functional roles of these eosinophil subtypes in asthma, as well as the phenotypic changes induced by clinical therapy with the anti-IL-5 biologic agent, mepolizumab. Improved understanding of distinct eosinophil phenotypes may enable targeting of select subpopulations in the treatment of patients with type 2 inflammatory diseases such as asthma.

Mechanistic study of inhibitory peptides with SHP-1 in hypertonic environment for infection model

Cutaneous Leishmaniasis, an infectious disease is globally the most prevalent form of leishmaniasis accounting for approximately 1 million cases every year as per world health organization. Infected individuals develop skin lesion which has been reported to be infiltrated by immune cells and parasite with high sodium accumulation creating hypertonic environment. In our work, we tried to mimic the hypertonic environment in virtual environment to study dynamicity of SHP-1 and NFAT5 along with their interactions through molecular dynamics simulation. We validated the SHP-1 and NFAT5 dynamics in infection and HSD conditions to study the impact of hypertonicity derived NFAT5 mediated response to L.major infection. We also evaluated our therapeutic peptides for their binding to SHP-1 and to form stable complex. Membrane stability with the peptides was analyzed to understand their ability to sustain mammalian membrane. We identified PepA to be a potential candidate to interact with SHP-1. Inhibition of SHP-1 through PepA to discern IL-10 and IL-12 reciprocity may be assessed in future and furnish us with a potential therapeutic molecule. HSD mice exhibited high pro-inflammatory response to L.major infection which resulted in reduced lesion size. Contrary to observations in HSD mice, infection model exhibited low pro-inflammatory response and increased lesion size with high parasite load. Thus, increase in NFAT5 expression and reduced SHP-1 expression may result in disease resolving effect which can be further studied through incorporation of synthetic circuit using PepA to modulate IL-10 and IL-12 reciprocity.

Deficiency and dysfunctional roles of natural killer T cells in patients with ARDS

Objective

Acute respiratory distress syndrome (ARDS) presents a global health challenge, characterized by significant morbidity and mortality. However, the role of natural killer T (NKT) cells in human ARDS remains poorly understood. Therefore, this study explored the numerical and functional status of NKT cells in patients with ARDS, examining their clinical relevance and interactions with macrophages and fibroblasts during various stages of the syndrome.

Methods

Peripheral blood from 40 ARDS patients and 30 healthy controls was analyzed, with paired samples of peripheral blood and bronchoalveolar lavage fluid (BALF) from seven ARDS patients. We measured levels of NKT cells, cytokines, CD69, programmed death-1 (PD-1), and annexin-V using flow cytometry, and extracellular matrix (ECM) protein expression using real-time PCR.

Results

ARDS patients exhibited decreased circulating NKT cells with elevated CD69 expression and enhanced IL-17 production. The reduction in NKT cells correlated with PaO2/FiO2 ratio, albumin, and C-reactive protein levels. Proliferative responses to α-galactosylceramide (α-GalCer) were impaired, and co-culturing NKT cells with monocytes or T cells from ARDS patients resulted in a reduced α-GalCer response. Increased and activated NKT cells in BALF induced proinflammatory cytokine release by macrophages and ECM protein expression in fibroblasts.

Conclusion

ARDS is associated with a numerical deficiency but functional activation of circulating NKT cells, showing impaired responses to α-GalCer and altered interactions with immune cells. The increase in NKT cells within BALF suggests their role in inducing inflammation and remodeling/fibrosis, highlighting the potential of targeting NKT cells as a therapeutic approach for ARDS.

Using Functional Genomic Data in Monocytes/Macrophages and Genotyping to Nominate Disease-Driving Single Nucleotide Polymorphisms and Target Genes in Juvenile Idiopathic Arthritis

Introduction

GWAS have identified multiple regions that confer risk for juvenile idiopathic arthritis (JIA). However, identifying the single nucleotide polymorphisms (SNPs) that drive disease risk is impeded by the SNPs' that identify risk loci being in linkage disequilibrium (LD) with hundreds of other SNPs. Since the causal SNPs remain unknown, it is difficult to identify target genes and use genetic information to inform patient care. We used genotyping and functional data in primary human monocytes/macrophages to nominate disease-driving SNPs on JIA risk haplotypes and identify their likely target genes.

Methods

We identified JIA risk haplotypes using Immunochip data from Hinks et al (Nature Gen 2013) and the meta-analysis from McIntosh et al (Arthritis Rheum 2017). We used genotyping data from 3,939 children with JIA and 14,412 healthy controls to identify SNPs that: (1) were situated within open chromatin in multiple immune cell types and (2) were more common in children with JIA than the controls (p< 0.05). We intersected the chosen SNPs (n=846) with regions of bi-directional transcription initiation characteristic of non-coding regulatory regions detected using dREG to analyze GRO-seq data. Finally, we used MicroC data to identify gene promoters interacting with the regulatory regions harboring the candidate causal SNPs.

Results

We identified 190 SNPs that overlap with dREG peaks in monocytes and126 SNPs that overlap with dREG peaks in macrophages. Of these SNPs, 101 were situated within dREG peaks in both monocytes and macrophages, suggesting that these SNPs exert their effects independent of the cellular activation state. MicroC data in monocytes identified 20 genes/transcripts whose promoters interact with the enhancers harboring the SNPs of interest.

Conclusion

SNPs in JIA risk regions that are candidate causal variants can be further screened using functional data such as GRO-seq. This process identifies a finite number of candidate causal SNPs, the majority of which are likely to exert their biological effects independent of cellular activation state in monocytes. Three-dimensional chromatin data generated with MicroC identifies genes likely to be influenced by these SNPs. These studies demonstrate the importance of investigations into the role of innate immunity in JIA.

Microphysiological Models of Lung Epithelium-Alveolar Macrophage Co-Cultures to Study Chronic Lung Disease

The interactions between immune cells and epithelial cells influence the progression of many respiratory diseases, such as chronic obstructive pulmonary disease (COPD). In vitro models allow for the examination of cells in controlled environments. However, these models lack the complex 3D architecture and vast multicellular interactions between the lung resident cells and infiltrating immune cells that can mediate cellular response to insults. In this study, three complementary microphysiological systems are presented to delineate the effects of cigarette smoke and respiratory disease on the lung epithelium. First, the Transwell system allows the co-culture of pulmonary immune and epithelial cells to evaluate cellular and monolayer phenotypic changes in response to cigarette smoke exposure. Next, the human and mouse precision-cut lung slices system provides a physiologically relevant model to study the effects of chronic insults like cigarette smoke with the dissection of specific interaction of immune cell subtypes within the structurally complex tissue environment. Finally, the lung-on-a-chip model provides an adaptable system for live imaging of polarized epithelial tissues that mimic the in vivo environment of the airways. Using a combination of these models, a complementary approach is provided to better address the intricate mechanisms of lung disease.

Tumor-infiltrating T lymphocytes: A promising immunotherapeutic target for preventing immune escape in cholangiocarcinoma

Cholangiocarcinoma (CCA) is becoming more common and deadly worldwide. Tumor-infiltrating T cell subtypes make distinct contributions to the immune system; collectively, they constitute a significant portion of the tumor microenvironment (TME) in CCA. By secreting cytokines and other chemicals, regulatory T cells (Tregs) decrease activated T cell responses, acting as immunosuppressors. Reduced CD8+ T cell activation results in stimulating programmed death-1 (PD-1), which undermines the immunological homeostasis of T lymphocytes. On the other hand, cancer cells are eliminated by activated cytotoxic T lymphocyte (CTL) through the perforin-granzyme or Fas-FasL pathways. Th1 and CTL immune cell infiltration into the malignant tumor is also facilitated by γδ T cells. A higher prognosis is typically implied by CD8+ T cell infiltration, and survival is inversely associated with Treg cell density. Immune checkpoint inhibitors, either singly or in combination, provide novel therapeutic strategies for CCA immunotherapy. Furthermore, it is anticipated that immunotherapeutic strategies-such as the identification of new immune targets, combination treatments involving several immune checkpoint inhibitors, and chimeric antigen receptor-T therapies (CAR-T)-will optimize the effectiveness of anti-CCA treatments while reducing adverse effects.

Hypoxia and inflammation induce synergistic transcriptome turnover in macrophages

Macrophages are effector immune cells that experience substantial changes to oxygenation when transiting through tissues, especially when entering tumors or infected wounds. How hypoxia alters gene expression and macrophage effector function at the post-transcriptional level remains poorly understood. Here, we use TimeLapse-seq to measure how inflammatory activation modifies the hypoxic response in primary macrophages. Nucleoside recoding sequencing allows the derivation of steady-state transcript levels, degradation rates, and transcriptional synthesis rates from the same dataset. We find that hypoxia produces distinct responses from resting and inflammatory macrophages. Hypoxia induces destabilization of mRNA transcripts, though inflammatory macrophages substantially increase mRNA degradation compared to resting macrophages. Increased RNA turnover results in the upregulation of ribosomal protein genes and downregulation of extracellular matrix components in inflammatory macrophages. Pathways regulated by mRNA decay in vitro are differentially regulated in tumor-associated macrophages implying that mixed stimuli could induce post-transcriptional regulation of macrophage function in solid tumors.

High Glucose Increases Lactate and Induces the Transforming Growth Factor Beta-Smad 1/5 Atherogenic Pathway in Primary Human Macrophages

Hundreds of millions of people worldwide are expected to suffer from diabetes mellitus. Diabetes is characterized as a dynamic and heterogeneous disease that requires deeper understanding of the pathophysiology, genetics, and metabolic shaping of this disease and its macro/microvascular complications. Macrophages play an essential role in regulating local immune responses, tissue homeostasis, and disease pathogenesis. Here, we have analyzed transforming growth factor beta 1 (TGFβ1)/Smad signaling in primary human macrophages grown in normal (NG) and high-glucose (HG; +25 mM glucose) conditions. Cell culture lactate concentration and cellular phosphofructokinase (PFK) activity were increased in HG concentrations. High glucose levels in the growth media led to increased macrophage mRNA expression of TGFβ1, and TGFβ-regulated HAMP and PLAUR mRNA levels, while the expression of TGFβ receptor II remained unchanged. Stimulation of cells with TGFβ1 protein lead to Smad2 phosphorylation in both NG and HG conditions, while the phosphorylation of Smad1/5 was detected only in response to TGFβ1 stimulation in HG conditions. The use of the specific Alk1/2 inhibitor dorsomorphin and the Alk5 inhibitor SB431542, respectively, revealed that HG conditions led TGFβ1 to activation of Smad1/5 signaling and its downstream target genes. Thus, high-glucose activates TGFβ1 signaling to the Smad1/5 pathway in primary human macrophages, which may contribute to cellular homeostasis in a harmful manner, priming the tissues for diabetic complications.

Combined regenerative rehabilitation improves recovery following volumetric muscle loss injury in a rat model

Volumetric muscle loss (VML) injury causes irreversible deficits in muscle mass and function, often resulting in permanent disability. The current standard of care is physical therapy, but it is limited in mitigating functional deficits. We have previously optimized a rehabilitation technique using electrically stimulated eccentric contraction training (EST) that improved muscle mass, strength, and size in VML-injured rats. A biosponge scaffold composed of extracellular matrix proteins has previously enhanced muscle function postVML. This study aimed to determine whether combining a regenerative therapy (i.e., biosponge) with a novel rehabilitation technique (i.e., EST) could enhance recovery in a rat model of VML. A VML defect was created by removing ~20% of muscle mass from the tibialis anterior muscle in adult male Lewis rats. Experimental groups included VML-injured rats treated with biosponge with EST or biosponge alone (n = 6/group). EST was implemented 2 weeks postinjury at 150 Hz and was continued for 4 weeks. A linear increase in eccentric torque over 4 weeks showed the adaptability of the VML-injured muscle to EST. Combining biosponge with EST improved peak isometric torque by ~52% compared with biosponge treatment alone at 6 weeks postinjury. Application of EST increased MyoD gene expression and the percentage of large (>2000 μm2) type 2B myofibers but reduced fibrotic tissue deposition in VML-injured muscles. Together, these changes may provide the basis for improved torque production. This study demonstrates the potential for combined regenerative and rehabilitative therapy to improve muscle recovery following VML.

Inflammatory and hypoxic stress-induced islet exosomes released during isolation are associated with poor transplant outcomes in islet autotransplantation

Islets experience enormous stress during the isolation process, leading to suboptimal endocrine function after total pancreatectomy with islet autotransplantation (TPIAT). Our investigation focused on inducing isolation stress in islets ex vivo, where proinflammatory cytokines and hypoxia prompted the release of stress exosomes (exoS) sized between 50 and 200 nm. Mass spectrometry analysis revealed 3 distinct subgroups of immunogenic proteins within these exoS: damage-associated molecular patterns (DAMPs), chaperones, and autoantigens. The involvement of endosomal-sorting complex required for transport proteins including ras-associated binding proteins7A, ras-associated binding protein GGTA, vacuolar protein sorting associated protein 45, vacuolar protein sorting associated protein 26B, and the tetraspanins CD9 and CD63, in exoS biogenesis was confirmed through immunoblotting. Next, we isolated similar exoS from the islet infusion bags of TPIAT recipients (N = 20). The exosomes from infusion bags exhibited higher DAMP (heat shock protein family A [Hsp70] member 1B and histone H2B) levels, particularly in the insulin-dependent TPIAT group. Additionally, elevated DAMP protein levels in islet infusion bag exosomes correlated with increased insulin requirements (P = .010) and higher hemoglobin A1c levels 1-year posttransplant. A deeper exploration into exoS functionality revealed their potential to activate monocytes via the toll-like receptor 3/7: DAMP axis. This stimulation resulted in the induction of inflammatory phenotypes marked by increased levels of CD68, CD80, inducible nitric oxide synthase, and cyclooxygenase-2. This activation mechanism may impact the successful engraftment of transplanted islets.

Hypoxia-induced TREM1 promotes mesenchymal-like states of glioma stem cells via alternatively activating tumor-associated macrophages

The mesenchymal subtype of glioblastoma (GBM) cells characterized by aggressive invasion and therapeutic resistance is thought to be dependent on cell-intrinsic alteration and extrinsic cellular crosstalk. Tumor-associated macrophages (TAMs) are pivotal in tumor progression, chemo-resistance, angiogenesis, and stemness maintenance. However, the impact of TAMs on the shifts in glioma stem cells (GSCs) states remains largely uncovered. Herein, we showed that the triggering receptor expressed on myeloid cells-1 (TREM1) preferentially expressed by M2-like TAMs and induced GSCs into mesenchymal-like states by modulating the secretion of TGFβ2, which activated the TGFβR/SMAD2/3 signaling in GSCs. Furthermore, we demonstrated that TREM1 was transcriptionally regulated by HIF1a under the hypoxic environment and thus promoted an immunosuppressive type of TAMs via activating the TLR2/AKT/mTOR/c-MYC axis. Collectively, this study reveals that cellular communication between TAMs and GSCs through the TREM1-mediated TGFβ2/TGFβR axis is involved in the mesenchymal-like transitions of GSCs. Our study provides valuable insights into the regulatory mechanisms between the tumor immune microenvironment and the malignant characteristics of GBM, which can lead to potential novel strategies targeting TAMs for tumor control.

The role of tumor-associated macrophages in tumor immune evasion

BACKGROUND

Tumor growth is closely linked to the activities of various cells in the tumor microenvironment (TME), particularly immune cells. During tumor progression, circulating monocytes and macrophages are recruited, altering the TME and accelerating growth. These macrophages adjust their functions in response to signals from tumor and stromal cells. Tumor-associated macrophages (TAMs), similar to M2 macrophages, are key regulators in the TME.

METHODS

We review the origins, characteristics, and functions of TAMs within the TME. This analysis includes the mechanisms through which TAMs facilitate immune evasion and promote tumor metastasis. Additionally, we explore potential therapeutic strategies that target TAMs.

RESULTS

TAMs are instrumental in mediating tumor immune evasion and malignant behaviors. They release cytokines that inhibit effector immune cells and attract additional immunosuppressive cells to the TME. TAMs primarily target effector T cells, inducing exhaustion directly, influencing activity indirectly through cellular interactions, or suppressing through immune checkpoints. Additionally, TAMs are directly involved in tumor proliferation, angiogenesis, invasion, and metastasis. Developing innovative tumor-targeted therapies and immunotherapeutic strategies is currently a promising focus in oncology. Given the pivotal role of TAMs in immune evasion, several therapeutic approaches have been devised to target them. These include leveraging epigenetics, metabolic reprogramming, and cellular engineering to repolarize TAMs, inhibiting their recruitment and activity, and using TAMs as drug delivery vehicles. Although some of these strategies remain distant from clinical application, we believe that future therapies targeting TAMs will offer significant benefits to cancer patients.

Using Macrophage Polarization in Human Platelet Lysate to Test the Immunomodulatory Potential of Cells for Clinical Use

Macrophage-based co-cultures are used to test the immunomodulatory function of candidate cells for clinical use. This study aimed to characterize a macrophage polarization model using human platelet lysate (hPL) as a GMP-compliant alternative to Fetal Bovine Serum (FBS). Primary human monocytes were differentiated into unpolarized (M0) or polarized (M1, M2a, and M2c) macrophages in an hPL- or FBS-based medium. The protein secretion profiles and expression of phenotypic markers (CD80 for M1, CD206 for M2a, and CD163 for M2c) were analyzed. Subsequently, chondrocytes were tested in an hPL-based co-culture model to assess their immunomodulatory function in view of their possible use in patients with osteoarthritis. The results showed similar marker regulation between hPL and FBS cultures, but lower basal levels of CD206 and CD163 in hPL-cultured macrophages. Functional co-culture experiments with chondrocytes revealed increased CD206 expression both in hPL and in FBS, indicating an interaction between macrophages and chondrocytes. While markers in FBS-cultured macrophages were confirmed in hPL-cultured cells, the interpretation of marker modulation in immunomodulatory assays with hPL-based cultures should be carried out cautiously due to the observed differences in the basal marker levels for CD206 and CD163. This research underscores the utility of hPL as a GMP-compliant alternative to FBS for macrophage-based co-cultures and highlights the importance of understanding marker expressions in different culture conditions.

M1 macrophages polarized by crude polysaccharides isolated from Auricularia polytricha exhibit anti-tumor effect on human breast cancer cells

Breast cancer has been reported to correlate with the infiltration of tumor-associated macrophages (TAMs) or M2-like macrophages in tumor microenvironment (TME) that could promote breast cancer progression. In contrast, M1-like macrophages displayed anti-tumor activity toward cancer. This study was focused on Auricularia polytricha (AP), a cloud ear mushroom, which has been reported for anti-tumor activity and immunomodulation. AP extracts were screened on differentiated THP-1 macrophages (M0). Results demonstrated that water extract (APW) and crude polysaccharides (APW-CP) could upregulate M1-related genes and cytokines production (IL-6, IL-1 β and TNF-α) significantly. Moreover, APW and APW-CP showed a high expression of CD86 (M1 marker) compared to M0. The NF-κB signaling pathway is crucial for pro-inflammatory gene regulation. The APW and APW-CP treatment showed the induction of the NF-κB pathway in a dose-dependent manner, which related to the β-glucan content in the extracts. Furthermore, APW-CP polarized macrophages were investigated for anti-tumor activity on human breast cancer cells (MCF-7 and MDA-MB-231). Results showed that APW-CP could inhibit the invasion of breast cancer cells and induce apoptosis. Therefore, M1 macrophages polarized by APW-CP showed anti-tumor activity against the breast cancer cells and β-glucan may be the potential M1-phenotype inducer.

The role of bile acid receptor TGR5 in regulating inflammatory signalling

Takeda G protein-coupled receptor 5 (TGR5) is a bile acid receptor, and its role in regulating metabolism after binding with bile acids has been established. Since the immune response depends on metabolism to provide biomolecules and energy to cope with challenging conditions, emerging evidence reveals the regulatory effects of TGR5 on the immune response. An in-depth understanding of the effect of TGR5 on immune regulation can help us disentangle the interaction of metabolism and immune response, accelerating the development of TGR5 as a therapeutic target. Herein, we reviewed more than 200 articles published in the last 20 years in PubMed, to discuss the roles of TGR5 in regulating inflammatory response, the molecular mechanism, as well as existing problems. Particularly, its anti-inflammation effect is emphasized.

The dance of macrophage death: the interplay between the inevitable and the microenvironment

Macrophages are highly plastic cells ubiquitous in various tissues, where they perform diverse functions. They participate in the response to pathogen invasion and inflammation resolution following the immune response, as well as the maintenance of homeostasis and proper tissue functions. Macrophages are generally considered long-lived cells with relatively strong resistance to numerous cytotoxic factors. On the other hand, their death seems to be one of the principal mechanisms by which macrophages perform their physiological functions or can contribute to the development of certain diseases. In this review, we scrutinize three distinct pro-inflammatory programmed cell death pathways - pyroptosis, necroptosis, and ferroptosis - occurring in macrophages under specific circumstances, and explain how these cells appear to undergo dynamic yet not always final changes before ultimately dying. We achieve that by examining the interconnectivity of these cell death types, which in macrophages seem to create a coordinated and flexible system responding to the microenvironment. Finally, we discuss the complexity and consequences of pyroptotic, necroptotic, and ferroptotic pathway induction in macrophages under two pathological conditions - atherosclerosis and cancer. We summarize damage-associated molecular patterns (DAMPs) along with other microenvironmental factors, macrophage polarization states, associated mechanisms as well as general outcomes, as such a comprehensive look at these correlations may point out the proper methodologies and potential therapeutic approaches.

Tolerogenic probiotics Lactobacillus delbrueckii and Lactobacillus rhamnosus promote anti-inflammatory profile of macrophages-derived monocytes of newly diagnosed patients with systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is known as an autoimmune disorder that is characterized by the breakdown of self-tolerance, resulting in disease onset and progression. Macrophages have been implicated as a factor in the development of SLE through faulty phagocytosis of dead cells or an imbalanced M1/M2 ratio. The study aimed to investigate the immunomodulatory effects of Lactobacillus delbrueckii and Lactobacillus rhamnosus on M1 and M2 macrophages in new case lupus patients. For this purpose, blood monocytes were collected from lupus patients and healthy people and were cultured for 5 days to produce macrophages. For 48 h, the macrophages were then cocultured with either probiotics or lipopolysaccharides (LPS). Flow cytometry and real-time polymerase chain reaction were then used to analyze the expression of cluster of differentiation (CD) 14, CD80, and human leukocyte antigen - DR (HLADR) markers, as well as cytokine expression (interleukin [IL]1-β, IL-12, tumor necrosis factor α [TNF-α], IL-10, and transforming growth factor beta [TGF-β]). The results indicated three distinct macrophage populations, M0, M1, and M2. In both control and patient-derived macrophage-derived monocytes (MDMs), the probiotic groups showed a decrease in CD14, CD80, and HLADR expression compared to the LPS group. This decrease was particularly evident in M0 and M2 macrophages from lupus patients and M1 macrophages from healthy subjects. In addition, the probiotic groups showed increased levels of IL-10 and TGF-β and decreased levels of IL-12, IL1-β, and TNF-α in MDMs from both healthy and lupus subjects compared to the LPS groups. Although there was a higher expression of pro-inflammatory cytokines in lupus patients, there was a higher expression of anti-inflammatory cytokines in healthy subjects. In general, L. delbrueckii and L. rhamnosus could induce anti-inflammatory effects on MDMs from both healthy and lupus subjects.

Targeting YAP1-regulated Glycolysis in Fibroblast-Like Synoviocytes Impairs Macrophage Infiltration to Ameliorate Diabetic Osteoarthritis Progression

The interplay between immune cells/macrophages and fibroblast-like synoviocytes (FLSs) plays a pivotal role in initiating synovitis; however, their involvement in metabolic disorders, including diabetic osteoarthritis (DOA), is largely unknown. In this study, single-cell RNA sequencing (scRNA-seq) is employed to investigate the synovial cell composition of DOA. A significant enrichment of activated macrophages within eight distinct synovial cell clusters is found in DOA synovium. Moreover, it is demonstrated that increased glycolysis in FLSs is a key driver for DOA patients' synovial macrophage infiltration and polarization. In addition, the yes-associated protein 1 (YAP1)/thioredoxin-interacting protein (TXNIP) signaling axis is demonstrated to play a crucial role in regulating glucose transporter 1 (GLUT1)-dependent glycolysis in FLSs, thereby controlling the expression of a series of adhesion molecules such as intercellular adhesion molecule-1 (ICAM-1) which may subsequently fine-tune the infiltration of M1-polarized synovial macrophages in DOA patients and db/db diabetic OA mice. For treatment, M1 macrophage membrane-camouflaged Verteporfin (Vt)-loaded PLGA nanoparticles (MVPs) are developed to ameliorate DOA progression by regulating the YAP1/TXNIP signaling axis, thus suppressing the synovial glycolysis and the infiltration of M1-polarized macrophages. The results provide several novel insights into the pathogenesis of DOA and offer a promising treatment approach for DOA.

Targeting Keap1 with Inulae Herba activated the Nrf2 receptor to alleviate LPS-mediated acute lung injury

ETHNOPHARMACOLOGICAL RELEVANCE

Inulae Herba (IH) is known as Jinfeicao recorded in Chinese Pharmacopoeia with effects of lowering qi and eliminating phlegm, and used for the treatment of pulmonary diseases. However, its protective mechanism on pulmonary diseases, especially acute lung injury (ALI), is still undefined.

AIM OF THE STUDY

This study aimed to explore anti-inflammatory and anti-oxidation effects of IH and its underlying mechanism for treating ALI.

MATERIALS AND METHODS

We constructed a lipopolysaccharide (LPS)-ALI mouse model to reveal the therapeutical effect of IH. Western blot, real-time quantitative PCR, flow cytometry, small RNA interference, immunohistochemical staining, and the dual-luciferase experiment were performed to study the mechanism of IH for treating ALI.

RESULTS

IH attenuated LPS-mediated pathological changes (e.g. pneumonedema and pulmonary congestion) through inactivation of macrophages in an ALI mouse model. The result of flow cytometry demonstrated that IH regulated the homeostasis of M1 (CD80+CD206-) and M2 (CD80+CD206+) phenotype macrophages. Furthermore, IH suppressed mRNA expressions of M1 phenotype markers, such as iNOS and IL-6, whereas promoted mRNA expressions of M2 phenotype markers, such as ARG1 and RETNLA in LPS-mediated mice. Notably, IH targeted Keap1 to activate the Nrf2 receptor, exerting its anti-inflammatory and anti-oxidation effects proved by using immunohistochemical staining, dual-luciferase, and Keap1 knockdown technologies.

CONCLUSION

These findings suggested that targeting Keap1 with IH alleviated LPS-mediated ALI, and it could serve as a herbal agent for developing anti-ALI drugs.

Unraveling the potential of CD8, CD68, and VISTA as diagnostic and prognostic markers in patients with pancreatic ductal adenocarcinoma

Introduction

Pancreatic cancer is a truculent disease with limited treatment options and a grim prognosis. Immunotherapy has shown promise in treating various types of cancer, but its effectiveness in pancreatic cancer has been lacking. As a result, it is crucial to identify markers associated with immunological pathways in order to improve the treatment outcomes for this deadly cancer. The purpose of this study was to investigate the diagnostic and prognostic significance of three markers, CD8, CD68, and VISTA, in pancreatic ductal adenocarcinoma (PDAC), the most common subtype of pancreatic cancer.

Methods

We analyzed gene expression data from Gene Expression Omnibus (GEO) database using bioinformatics tools. We also utilized the STRING online tool and Funrich software to study the protein-protein interactions and transcription factors associated with CD8, CD68, and VISTA. In addition, tissue microarray (TMA) and immunohistochemistry (IHC) staining were performed on 228 samples of PDAC tissue and 10 samples of normal pancreatic tissue to assess the expression levels of the markers. We then correlated these expression levels with the clinicopathological characteristics of the patients and evaluated their survival rates.

Results

The analysis of the GEO data revealed slightly elevated levels of VISTA in PDAC samples compared to normal tissues. However, there was a significant increase in CD68 expression and a notable reduction in CD8A expression in pancreatic cancer. Further investigation identified potential protein-protein interactions and transcription factors associated with these markers. The IHC staining of PDAC tissue samples showed an increased expression of VISTA, CD68, and CD8A in pancreatic cancer tissues. Moreover, we found correlations between the expression levels of these markers and certain clinicopathological features of the patients. Additionally, the survival analysis revealed that high expression of CD8 was associated with better disease-specific survival and progression-free survival in PDAC patients.

Conclusion

These findings highlight the potential of CD8, CD68, and VISTA as diagnostic and prognostic indicators in PDAC.

Characterizing ligand-receptor interactions and unveiling the pro-tumorigenic role of CCL16-CCR1 axis in the microenvironment of hepatocellular carcinoma

Background

The heterogeneity of the tumor microenvironment significantly influences the prognosis of hepatocellular carcinoma (HCC) patients, with cell communication through ligand-receptor complexes playing a central role.

Methods

We conducted single-cell transcriptomic analysis on ten HCC tissues to identify ligand-receptor genes involved in malignant HCC cell communication using CellChat. Leveraging RNA-Seq data from the TCGA Liver Cancer (TCGA-LIHC) and Liver Cancer - RIKEN, JP (LIRI-JP) cohorts, we employed Cox regression analysis to screen for prognosis-related genes. Prognostic risk models were constructed through unsupervised clustering and differential gene expression analysis. Subsequently, a co-culture system involving tumor cells and macrophages was established. A series of experiments, including Transwell assays, immunofluorescence staining, immunoprecipitation, flow cytometry, and immunohistochemistry, were conducted to elucidate the mechanism through which HCC cells recruit macrophages via the CCL16-CCR1 axis.

Results

Single-cell analysis unveiled significant interactions between malignant HCC cells and macrophages, identifying 76 related ligand-receptor genes. Patients were classified into three subtypes based on the expression patterns of eight prognosis-related ligand-receptor genes. The subtype with the worst prognosis exhibited reduced infiltration of T cell-related immune cells, downregulation of immune checkpoint genes, and increased M2-like tumor-associated macrophage scores. In vitro experiments confirmed the pivotal role of the CCL16-CCR1 axis in the recruitment and M2 polarization of tumor-associated macrophages. Clinical samples demonstrated a significant association between CCL16 protein expression levels and advanced stage, lymph node metastasis, and distant metastasis. Immunohistochemistry and immunofluorescence staining further confirmed the correlation between CCL16 and CCR1, CD68, and CD206, as well as CD68+CCR1+ macrophage infiltration.

Conclusions

Our study identified molecular subtypes, a prognostic model, and immune microenvironment features based on ligand-receptor interactions in malignant HCC cell communication. Moreover, we revealed the pro-tumorigenic role of HCC cells in recruiting M2-like tumor-associated macrophages through the CCL16-CCR1 axis.

Engagement of CD300c by a novel monoclonal antibody induces the differentiation of monocytes to M1 macrophages

Human CD300c is expressed on various immune or cancer cells and is a novel B7 family member, functioning as an activity modulator on immune cells. To elucidate the function of CD300c, we developed CL7, a human CD300c-specific monoclonal antibody, and assessed its biological activity. The specific binding of CL7 monoclonal antibody against recombinant CD300c antigen was confirmed using enzyme-linked immunosorbent assay and surface plasmon resonance analysis. The binding affinity of CL7 was strong at the sub-nanomolar level. Furthermore, CL7 effectively bound to exogenously expressed CD300c on 293T cells. CL7 antibody differentiated monocytes to M1 macrophages, as evidenced by the upregulated expression of M1-specific cell surface markers and increased secretion of M1-specific cytokines in vitro in THP-1 cells and primary macrophages, as well as the increased population size of M1 macrophages in tumors grafted into mice. Additionally, CL7 treatment upregulated PD-L1 expression on THP-1 cells. We confirmed that the mechanism of M1 macrophage differentiation was through the mitogen-activated protein kinase and NF-κB signaling pathways. CD300c expression on various immune and cancer cells was similar to that of the well-known immune checkpoint PD-L1, suggesting the possibility of CD300c as a novel tumor biomarker. We also confirmed that the tumor size was substantially reduced by CL7 antibody treatment in the CT26 mouse model. Our study supports that CD300c is a potential therapeutic target in immuno-oncology. Overall, the CD300c-specific monoclonal antibody, CL7, is a promising immunotherapeutic agent, and it induces enhanced differentiation of M1 macrophages and/or their infiltration into the tumor microenvironment.

Regulatory macrophages in solid organ xenotransplantation

Due to a critical organ shortage, pig organs are being explored for use in transplantation. Differences between species, particularly in cell surface glycans, can trigger elevated immune responses in xenotransplantation. To mitigate the risk of hyperacute rejection, genetically modified pigs have been developed that lack certain glycans and express human complement inhibitors. Nevertheless, organs from these pigs may still provoke stronger inflammatory and innate immune reactions than allotransplants. Dysregulation of coagulation and persistent inflammation remain obstacles in the transplantation of pig organs into primates. Regulatory macrophages (Mregs), known for their anti-inflammatory properties, could offer a potential solution. Mregs secrete interleukin 10 and transforming growth factor beta, thereby suppressing immune responses and promoting the development of regulatory T cells. These Mregs are typically induced via the stimulation of monocytes or macrophages with macrophage colony-stimulating factor and interferon gamma, and they conspicuously express the stable marker dehydrogenase/reductase 9. Consequently, understanding the precise mechanisms governing Mreg generation, stability, and immunomodulation could pave the way for the therapeutic use of Mregs generated in vitro. This approach has the potential to reduce the required dosages and durations of anti-inflammatory and immunosuppressive medications in preclinical and clinical settings.

Radiogenomic landscape: Assessment of specific phagocytosis regulators in lower-grade gliomas

Genome-wide CRISPR-Cas9 knockout screens have emerged as a powerful method for identifying key genes driving tumor growth. The aim of this study was to explore the phagocytosis regulators (PRs) specifically associated with lower-grade glioma (LGG) using the CRISPR-Cas9 screening database. Identifying these core PRs could lead to novel therapeutic targets and pave the way for a non-invasive radiogenomics approach to assess LGG patients' prognosis and treatment response. We selected 24 PRs that were overexpressed and lethal in LGG for analysis. The identified PR subtypes (PRsClusters, geneClusters, and PRs-score models) effectively predicted clinical outcomes in LGG patients. Immune response markers, such as CTLA4, were found to be significantly associated with PR-score. Nine radiogenomics models using various machine learning classifiers were constructed to uncover survival risk. The area under the curve (AUC) values for these models in the test and training datasets were 0.686 and 0.868, respectively. The CRISPR-Cas9 screen identified novel prognostic radiogenomics biomarkers that correlated well with the expression status of specific PR-related genes in LGG patients. These biomarkers successfully stratified patient survival outcomes and treatment response using The Cancer Genome Atlas (TCGA) database. This study has important implications for the development of precise clinical treatment strategies and holds promise for more accurate therapeutic approaches for LGG patients in the future.

PAK in Pancreatic Cancer-Associated Vasculature: Implications for Therapeutic Response

Angiogenesis has been associated with numbers of solid tumours. Anti-angiogenesis drugs starve tumours of nutrients and oxygen but also make it difficult for a chemo reagent to distribute into a tumour, leading to aggressive tumour growth. Anti-angiogenesis drugs do not appear to improve the overall survival rate of pancreatic cancer. Vessel normalisation is merging as one of the new approaches for halting tumour progression by facilitating the tumour infiltration of immune cells and the delivery of chemo reagents. Targeting p21-activated kinases (PAKs) in cancer has been shown to inhibit cancer cell growth and improve the efficacy of chemotherapy. Inhibition of PAK enhances anti-tumour immunity and stimulates the efficacy of immune checkpoint blockades. Inhibition of PAK also improves Car-T immunotherapy by reprogramming the vascular microenvironment. This review summarizes current research on PAK's role in tumour vasculature and therapeutical response, with a focus on pancreatic cancer.

The common H232 STING allele shows impaired activities in DNA sensing, susceptibility to viral infection, and in monocyte cell function, while the HAQ variant possesses wild-type properties

Different innate immune pathways converge to Stimulator of interferon genes (STING) and trigger type I interferon responses after recognition of abnormal nucleic acids in the cells. This non-redundant function renders STING a major player in immunosurveillance, and an emerging target for cancer and infectious diseases therapeutics. Beyond somatic mutations that often occur in cancer, the human gene encoding STING protein, TMEM173 (STING1), holds great genetic heterogeneity; R232, HAQ (R71H-G230A-R293Q) and H232 are the most common alleles. Although some of these alleles are likely to be hypomorphic, their function is still debated, due to the available functional assessments, which have been performed in biased biological systems. Here, by using genetic background-matched models, we report on the functional evaluation of R232, HAQ and H232 variants on STING function, and on how these genotypes affect the susceptibility to clinically relevant viruses, thus supporting a potential contributing cause to differences in inter-individual responses to infections. Our findings also demonstrate a novel toll-like receptor-independent role of STING in modulating monocytic cell function and differentiation into macrophages. We further supported the interplay of STING1 variants and human biology by demonstrating how monocytes bearing the H232 allele were impaired in M1/M2 differentiation, interferon response and antigen presentation. Finally, we assessed the response to PD-1 inhibitor in a small cohort of melanoma patients stratified according to STING genotype. Given the contribution of the STING protein in sensing DNA viruses, bacterial pathogens and misplaced cancer DNA, these data may support the development of novel therapeutic options for infectious diseases and cancer.

Characterization of polarization states of canine monocyte derived macrophages

Macrophages can reversibly polarize into multiple functional subsets depending on their micro-environment. Identification and understanding the functionality of these subsets is relevant for the study of immune‑related diseases. However, knowledge about canine macrophage polarization is still in its infancy. In this study, we polarized canine monocytes using GM-CSF/IFN- γ and LPS towards M1 macrophages or M-CSF and IL-4 towards M2 macrophages and compared them to undifferentiated monocytes (M0). Polarized M1 and M2 macrophages were thoroughly characterized for morphology, surface marker features, gene profiles and functional properties. Our results showed that canine M1-polarized macrophages obtained a characteristic large, roundish, or amoeboid shape, while M2-polarized macrophages were smaller and adopted an elongated spindle-like morphology. Phenotypically, all macrophage subsets expressed the pan-macrophage markers CD14 and CD11b. M1-polarized macrophages expressed increased levels of CD40, CD80 CD86 and MHC II, while a significant increase in the expression levels of CD206, CD209, and CD163 was observed in M2-polarized macrophages. RNAseq of the three macrophage subsets showed distinct gene expression profiles, which are closely associated with immune responsiveness, cell differentiation and phagocytosis. However, the complexity of the gene expression patterns makes it difficult to assign clear new polarization markers. Functionally, undifferentiated -monocytes, and M1- and M2- like subsets of canine macrophages can all phagocytose latex beads. M2-polarized macrophages exhibited the strongest phagocytic capacity compared to undifferentiated monocytes- and M1-polarized cells. Taken together, this study showed that canine M1 and M2-like macrophages have distinct features largely in parallel to those of well-studied species, such as human, mouse and pig. These findings enable future use of monocyte derived polarized macrophages particularly in studies of immune related diseases in dogs.

Umbilical cord mesenchymal stromal cell-derived extracellular vesicles lack the potency to immunomodulate human monocyte-derived macrophages in vitro

Mesenchymal stromal cells (MSCs) have been reported to display efficacy in a variety of preclinical models, but without long-term engraftment, suggesting a role for secreted factors, such as MSC-derived extracellular vesicles (EVs). MSCs are known to elicit immunomodulatory effects, an important aspect of which is their ability to affect macrophage phenotype. However, it is not clear if these effects are mediated by MSC-derived EVs, or other factors secreted by the MSCs. Here, we use flow cytometry to assess the effects of human umbilical cord (hUC) MSC-derived EVs on the expression of pro-inflammatory (CD80) and anti-inflammatory (CD163) surface markers in human monocyte-derived macrophages (hMDMs). hUC-MSC-derived EVs did not change the surface marker expression of the hMDMs. In contrast, when hMDMs were co-incubated with hUC-MSCs in indirect co-cultures, changes were observed in the expression of CD14, CD80 and CD163, particularly in M1 macrophages, suggesting that soluble factors are necessary to elicit a shift in phenotype. However, even though EVs did not alter the surface marker expression of macrophages, they promoted angiogenesis and phagocytic capacity increased proportionally to increases in EV concentration. Taken together, these results suggest that hUC-MSC-derived EVs are not sufficient to alter macrophage phenotype and that additional MSC-derived factors are needed.

Defining the proteomic landscape of cultured macrophages and their polarization continuum

Macrophages have previously been characterized based on phenotypical and functional differences into suggested simplified subtypes of MØ, M1, M2a and M2c. These macrophage subtypes can be generated in a well-established primary monocyte culture model that produces cells expressing accepted subtype surface markers. To determine how these subtypes retain functional similarities and better understand their formation, we generated all four subtypes from the same donors. Comparative whole-cell proteomics confirmed that four distinct macrophage subtypes could be induced from the same donor material, with > 50% of 5435 identified proteins being significantly altered in abundance between subtypes. Functional assessment highlighted that these distinct protein expression profiles are primed to enable specific cell functions, indicating that this shifting proteome is predictive of meaningful changes in cell characteristics. Importantly, the 2552 proteins remained consistent in abundance across all macrophage subtypes examined, demonstrating maintenance of a stable core proteome that likely enables swift polarity changes. We next explored the cross-polarization capabilities of preactivated M1 macrophages treated with dexamethasone. Importantly, these treated cells undergo a partial repolarization toward the M2c surface markers but still retain the M1 functional phenotype. Our investigation of polarized macrophage subtypes therefore provides evidence of a sliding scale of macrophage functionality, with these data sets providing a valuable benchmark resource for further studies of macrophage polarity, with relevance for cell therapy development and drug discovery.