M2b macrophage polarization and its roles in diseases

Emerging advances in nano-biomaterial assisted amyloid beta chimeric antigen receptor macrophages (CAR-M) therapy: reducing plaque burden in Alzheimer's disease

Alzheimer's disease is the most common form, accounting for 60-70% of 55 million dementia cases. Even though the precise pathophysiology of AD is not completely understood, clinical trials focused on antibodies targeting aggregated forms of β amyloid (Aβ) have demonstrated that reducing amyloid plaques can arrest cognitive decline in patients in the early stages of AD. In this study, we provide an overview of current research and innovations for controlled release from nano-biomaterial-assisted chimeric antigen receptor macrophage (CAR-M) therapeutic strategies targeted at AD. Nano-bio materials, such as iron-oxide nanoparticles (IONPs), can be made selectively (Hp-Hb/mannose) to bind and take up Aβ plaques like CAR-M cells. By using nano-bio materials, both the delivery and stability of CAR-M cells in brain tissue can be improved to overcome the barriers of the BBB and enhance therapeutic effects. By enhancing the targeting capabilities and stability of CAR-M cells, mRNA-loaded nano-biomaterials can significantly improve the efficacy of immunotherapy for plaque reduction in AD. This novel strategy holds promise for translating preclinical successes into clinical applications, potentially revolutionising the management of AD.

The role of macrophage polarization in ulcerative colitis and its treatment

Macrophages have great plasticity. Typically, there are two of activated macrophages: M1 macrophages and M2 macrophages. Of them, M1 macrophages play a major role in responses that are pro-inflammatory, while M2 macrophages play an important part in responses that are anti-inflammatory. Ulcerative colitis (UC) is a chronic, non-specific inflammatory disease of the intestine. The pathophysiology and course of UC are significantly influenced by the inflammatory response triggered by macrophage activation. M1 is a possible cause of increased inflammation in UC whereas M2 has a significant function in the healing of inflammation. The polarization imbalance of intestinal M1/M2 macrophages is closely linked to UC. Thus, by suppressing M1 polarization, encouraging M2 polarization, and reestablishing macrophage polarization balance, the treatment of UC based on macrophage polarization is beneficial for UC. Not only chemical drugs, but also traditional Chinese medicine compounds and herbal extracts have been shown to restore the balance of macrophage polarization, providing a new idea in the treatment of UC.

Kupffer cells, the limelight in the liver regeneration

Kupffer cells are pivotal in initiating hepatocyte proliferation and establishing connections between different cell types during liver regeneration following partial hepatectomy. As resident macrophages within the liver, Kupffer cells collaborate with hepatocytes and non-parenchymal cells to release various inflammatory mediators that promote hepatocyte proliferation through induction signals like STAT3 phosphorylation. Additionally, the regeneration and replenishment of Kupffer cells themselves are integral components of liver regeneration. The supplementation of the Kupffer cell pool primarily occurs through two pathways: one involves local proliferation of Kupffer cells in their original location, while the other entails infiltration of circulating monocytes into the liver, followed by acquiring Kupffer cell phenotypes under the combined influence of multiple inducing factors. Extensive research has focused on intercellular crosstalk among various types of liver cells during liver regeneration, highlighting the crucial role played by Kupffer cells. This article aims to introduce Kupffer cells and their involvement in liver regeneration, as well as discuss the steady-state balance of Kupffer cell pools during this process.

Tumor microenvironment noise-induced polarization: the main challenge in macrophages' immunotherapy for cancer

Disturbance of epigenetic processes can lead to altered gene function and malignant cellular transformation. In particular, changes in the epigenetic landscape are a central topic in cancer biology. The initiation and progression of cancer are now recognized to involve both epigenetic and genetic alterations. In this paper, we study the epigenetic mechanism (related to the tumor microenvironment) responsible for increasing tumor-associated macrophages that promote the occurrence and metastasis of tumor cells, support tumor angiogenesis, inhibit T-cell-mediated anti-tumor immune response, and lead to tumor progression. We show that the tumor benefits from the macrophages' high degree of plasticity and larger epigenetic basins corresponding to phenotypes that favor cancer development through a process that we call noise-induced polarization. Moreover, we propose a mechanism to promote the appropriate epigenetic stability for immunotherapies involving macrophages, which includes p53 and APR-246 (eprenetapopt). Our results show that a combination therapy may be necessary to ensure the proper epigenetic stability of macrophages, which otherwise will contribute to cancer progression. On the other hand, we conclude that macrophages may remain in the anti-tumoral state in types of cancer that exhibit less TP53 mutation, like colorectal cancer; in these cases, macrophages' immunotherapy may be more suitable. We finally mention the relevance of the epigenetic potential (Waddington's landscape) as the backbone for our study, which encapsulates the biological information of the system.

Luteolin modulates macrophage phenotypic switching via the AMPK-PPARγ pathway to alleviate ulcerative colitis in mice

ETHNOPHARMACOLOGICAL RELEVANCE

Lonicerae japonicae flos (LJF), the dried flower bud or newly bloomed flower of Lonicera japonica Thunb., is widely used in Traditional Chinese medicine (TCM), exhibiting anti-inflammatory and immune-enhancing properties. Luteolin (Lut) is a major bioactive component of LJF, demonstrating a regulatory role in immune disorders. However, the specific role of Lut in regulating macrophage-mediated intestinal inflammation and its underlying molecular mechanisms have not yet been fully explored.

AIM OF THE STUDY

This study was designed to explore whether Lut alleviates Ulcerative colitis (UC) in mice and to elucidate its underlying mechanism in intestinal inflammation.

MATERIALS AND METHODS

Mice were administered Dextran sodium sulfate (DSS) for 7 d to establish a UC model, followed by oral administration of Lut (12.5, 25, and 50 mg/kg body weight). RNA-sequencing (RNA-Seq) was used to screen signaling pathways. RAW264.7 cells were cultured and treated with Lut (6.25, 12.5, and 25 μM) and lipopolysaccharide (LPS, 1 μg/mL) for 24 h. To examine the role of the AMP-activated protein kinase (AMPK)/Peroxisome proliferator-activated receptor γ (PPARγ) signaling pathway, the cells were treated with compound C (an AMPK inhibitor) and GW9662 (a PPARγ antagonist).

RESULTS

Lut suppressed the inflammation of DSS-induced colitis in vivo, attenuated DSS-induced clinical man-ifestations, reversed colon length reduction, and reduced histological injury. Lut induced a shift in the macrophage phenotype from classical (M1) to alternative (M2) by suppressing M1 marker gene expression and enhancing M2 marker gene expression following DSS or LPS induction. RNA-seq revealed that PPARγ was involved in the regulation of macrophages by Lut. Furthermore, the polarization effect of Lut on macrophages was shown to be mediated through the AMPK-PPARγ signaling pathway.

CONCLUSION

These findings indicate that Lut effectively ameliorates UC in mice through the activation of the AMPK-PPARγ signaling pathway, leading to the inhibition of macrophage M1 polarization and promotion of M2 polarization. This study provides insight into future research on the utilization of Lut-rich TCM dietary supplements as a prophylactic treatment strategy in the prevention of UC.

Clinical-grade extracellular vesicles derived from umbilical cord mesenchymal stromal cells: preclinical development and first-in-human intra-articular validation as therapeutics for knee osteoarthritis

Osteoarthritis (OA) is a joint disease characterized by articular cartilage degradation. Persistent low-grade inflammation defines OA pathogenesis, with crucial involvement of pro-inflammatory M1-like macrophages. While mesenchymal stromal cells (MSC) and their small extracellular vesicles (sEV) hold promise for OA treatment, achieving consistent clinical-grade sEV products remains a significant challenge. This study aims to develop fully characterized, reproducible, clinical-grade batches of sEV derived from umbilical cord (UC)-MSC for the treatment of OA while assessing its efficacy and safety. Initially, a standardized, research-grade manufacturing protocol was established to ensure consistent sEV production. UC-MSC-sEV characterization under non-cGMP conditions showed consistent miRNA and protein profiles, suggesting their potential for standardized manufacturing. In vitro studies evaluated the efficacy, safety, and potency of sEV; animal studies confirmed their effectiveness and safety. In vitro, UC-MSC-sEV polarized macrophages to an anti-inflammatory M2b-like phenotype, through STAT1 modulation, indicating their potential to create an anti-inflammatory environment in the affected joints. In silico studies confirmed sEV's immunosuppressive signature through miRNA and proteome analysis. In an OA mouse model, sEV injected intra-articularly (IA) induced hyaline cartilage regeneration, validated by histological and μCT analyses. The unique detection of sEV signals within the knee joint over time highlights its safety profile by confirming the retention of sEV in the joint. The product development of UC-MSC-sEV involved refining, standardizing, and validating processes in compliance with GMP standards. The initial assessment of the safety of the clinical-grade product via IA administration in a first-in-human study showed no adverse effects after a 12 month follow-up period. These results support the progress of this sEV-based therapy in an early-phase clinical trial, the details of which are presented and discussed in this work. This study provides data on using UC-MSC-sEV as local therapy for OA, highlighting their regenerative and anti-inflammatory properties and safety in preclinical and a proof-of-principle clinical application.

Macrophage polarization in sepsis: Emerging role and clinical application prospect

Sepsis is a severe, potentially fatal condition defined by organ dysfunction due to excessive inflammation. Its complex pathogenesis and poor therapeutic outcomes pose significant challenges in treatment. Macrophages, with their high heterogeneity and plasticity, play crucial roles in both the innate and adaptive immune systems. They can polarize into M1-like macrophages, which promote pro-inflammatory responses, or M2-like macrophages, which mediate anti-inflammatory responses, positioning them as critical mediators in the immune response during sepsis.Macrophages are the main regulators of inflammatory responses, and their polarization is also regulated by inflammatory signaling pathways. This review highlights recent advances in the inflammatory signaling pathways involved in sepsis, mechanism of macrophage polarization mediated by inflammation-related signaling pathways in sepsis, and the role of signaling pathway mediated macrophage polarization in organ dysfunction involved in sepsis. We also explore the therapeutic potential of targeting macrophage polarization for immunotherapy, offering new perspectives on macrophage-targeted treatments for sepsis.

Emerging regulatory mechanisms and functions of biomolecular condensates: implications for therapeutic targets

Cells orchestrate their processes through complex interactions, precisely organizing biomolecules in space and time. Recent discoveries have highlighted the crucial role of biomolecular condensates-membrane-less assemblies formed through the condensation of proteins, nucleic acids, and other molecules-in driving efficient and dynamic cellular processes. These condensates are integral to various physiological functions, such as gene expression and intracellular signal transduction, enabling rapid and finely tuned cellular responses. Their ability to regulate cellular signaling pathways is particularly significant, as it requires a careful balance between flexibility and precision. Disruption of this balance can lead to pathological conditions, including neurodegenerative diseases, cancer, and viral infections. Consequently, biomolecular condensates have emerged as promising therapeutic targets, with the potential to offer novel approaches to disease treatment. In this review, we present the recent insights into the regulatory mechanisms by which biomolecular condensates influence intracellular signaling pathways, their roles in health and disease, and potential strategies for modulating condensate dynamics as a therapeutic approach. Understanding these emerging principles may provide valuable directions for developing effective treatments targeting the aberrant behavior of biomolecular condensates in various diseases.

Metabolic and epigenetic regulation of macrophage polarization in atherosclerosis: Molecular mechanisms and targeted therapies

Atherosclerosis, a multifactorial progressive inflammatory disease, is the common pathology underlying cardiovascular and cerebrovascular diseases. The macrophage plasticity is involved in the pathogenesis of atherosclerosis. With the advance of metabolomics and epigenetics, metabolites/metabolic and epigenetic modification such as DNA methylation, histone modification and noncoding RNA, play a crucial role in macrophage polarization and the progression of atherosclerosis. Herein, we provide a comprehensive review of the essential role of metabolic and epigenetic regulation, as well as the crosstalk between the two in regulating macrophage polarization in atherosclerosis. We also highlight the potential therapeutic strategies of regulating macrophage polarization via epigenetic and metabolic modifications for atherosclerosis, and offer recommendations to advance our knowledge of the roles of metabolic-epigenetic crosstalk in macrophage polarization in the context of atherosclerosis. Fundamental studies that elucidate the mechanisms by which metabolic and epigenetic regulation of macrophage polarization influence atherosclerosis will pave the way for novel therapeutic approaches.

Epigenetic regulatory mechanism of macrophage polarization in diabetic wound healing (Review)

Diabetic wounds represent a significant complication of diabetes and present a substantial challenge to global public health. Macrophages are crucial effector cells that play a pivotal role in the pathogenesis of diabetic wounds, through their polarization into distinct functional phenotypes. The field of epigenetics has emerged as a rapidly advancing research area, as this phenomenon has the potential to markedly affect gene expression, cellular differentiation, tissue development and susceptibility to disease. Understanding epigenetic mechanisms is crucial to further exploring disease pathogenesis. A growing body of scientific evidence has highlighted the pivotal role of epigenetics in the regulation of macrophage phenotypes. Various epigenetic mechanisms, such as DNA methylation, histone modification and non‑coding RNAs, are involved in the modulation of macrophage phenotype differentiation in response to the various environmental stimuli present in diabetic wounds. The present review provided an overview of the various changes that take place in macrophage phenotypes and functions within diabetic wounds and discussed the emerging role of epigenetic modifications in terms of regulating macrophage plasticity in diabetic wounds. It is hoped that this synthesis of information will facilitate the elucidation of diabetic wound pathogenesis and the identification of potential therapeutic targets.

S100A8/A9 drives monocytes towards M2-like macrophage differentiation and associates with M2-like macrophages in osteoarthritic synovium

OBJECTIVES

Macrophages are key orchestrators of the osteoarthritis (OA)-associated inflammatory response. Macrophage phenotype is dependent on environmental cues like the inflammatory factor S100A8/A9. Here, we investigated how S100A9 exposure during monocyte-to-macrophage differentiation affects macrophage phenotype and function.

METHODS

OA synovium cellular composition was determined using flow cytometry and multiplex immunohistochemistry. Healthy donor monocytes were differentiated towards M1- and M2-like macrophages in the presence of S100A9. Macrophage markers were measured using flow cytometry, and phagocytic activity was determined using pHrodo Red Zymosan A BioParticles. Gene expression was determined using qPCR. Protein secretion was measured using Luminex multianalyte analysis and ELISA.

RESULTS

Macrophages were the dominant leucocyte subpopulation in OA synovium. They mainly presented with an M2-like phenotype, although the majority also expressed M1-like macrophage markers. Long-term exposure to S100A9 during monocyte-to-macrophage differentiation increased M2-like macrophage markers CD163 and CD206 in M1-like and M2-like differentiated cells. In addition, M1-like macrophage markers were increased in M1-like, but decreased in M2-like differentiated macrophages. In agreement with this mixed phenotype, S100A9 stimulation modestly increased expression and secretion of pro-inflammatory markers and catabolic enzymes, but also increased expression and secretion of anti-inflammatory/anabolic markers. In accordance with the upregulation of M2-like macrophage markers, S100A9 increased phagocytic activity. Finally, we indeed observed a strong association between S100A8 and S100A9 expression and the M2-like/M1-like macrophage ratio in end-stage OA synovium.

CONCLUSION

Chronic S100A8/A9 exposure during monocyte-to-macrophage differentiation favours differentiation towards an M2-like macrophage phenotype. The properties of these cells could help explain the catabolic/anabolic dualism in established OA joints with low-grade inflammation.

Key role of macrophages in the progression of hepatic fibrosis

Liver fibrosis is a pathological change characterized by excessive deposition of extracellular matrix caused by chronic liver injury, and the mechanisms underlying its development are associated with endothelial cell injury, inflammatory immune cell activation, and HSC activation. Furthermore, hepatic macrophages exhibit remarkable heterogeneity and hold central functions in the evolution of liver fibrosis, with different subgroups exerting dual effects of promotion and regression. Currently, targeted macrophage therapy for reversing hepatic fibrosis has been extensively studied and has shown promising prospects. In this review, we will discuss the dual role of macrophages in liver fibrosis and provide new insights into reversing liver fibrosis based on macrophages.

The multiple roles of macrophages in peritoneal adhesion

Peritoneal adhesion (PA) refers to the abnormal adhesion of the peritoneum either with the peritoneum itself or with tissues and organs that is caused by abdominopelvic surgery, abdominal infection or peritoneal inflammation. PA is associated with various clinical complications, such as abdominal pain and distension, intestinal obstruction, gastrointestinal disorders and female infertility, and adversely affects the quality of life of patients. Macrophages are essential for PA formation and can undergo polarization into classically activated macrophages (M1) and alternatively activated macrophages (M2), which are influenced by the peritoneal microenvironment. By releasing proinflammatory cytokines and reactive oxygen species, M1 macrophages promote peritoneal inflammatory reactions and the resultant formation of adhesion. In contrast, M2 macrophages secrete anti-inflammatory cytokines and growth factors to inhibit PA formation and to promote repair and healing of peritoneal tissues, and thereby play a significant anti-inflammatory role. This review comprehensively explores the function and mechanism of macrophages and their subtypes in PA formation to gain insight into the prevention and treatment of PA based on the modulation of macrophages.

Leukemia inhibitory factor drives transcriptional programs that promote lipid accumulation and M2 polarization in macrophages

Leukemia inhibitory factor, a member of the interleukin-6 cytokine family, plays a central role in homeostasis and disease. Interestingly, some of the pleiotropic effects of leukemia inhibitory factor have been attributed to the modulation of macrophage functions although the molecular underpinnings have not been explored at a genome-wide scale. Herein, we investigated leukemia inhibitory factor-driven transcriptional changes in murine bone marrow-derived macrophages by RNA sequencing. In silico analyses revealed a selective and time-dependent remodeling of macrophage gene expression programs associated with lipid metabolism and cell activation. Accordingly, a subset of leukemia inhibitory factor-upregulated transcripts related to cholesterol metabolism and lipid internalization was validated by real-time quantitative polymerase chain reaction. This was accompanied by a leukemia inhibitory factor-enhanced capacity for lipid accumulation in macrophages upon incubation with oxidized low-density lipoprotein. Mechanistically, leukemia inhibitory factor triggered the phosphorylation (Y705 and S727) and nuclear translocation of the transcription factor STAT3 in bone marrow-derived macrophages. Consistent with this, ingenuity pathway analysis identified STAT3 as an upstream regulator of a subset of transcripts, including Il4ra, in leukemia inhibitory factor-treated macrophages. Notably, leukemia inhibitory factor priming enhanced bone marrow-derived macrophage responses to interleukin-4-mediated M2 polarization (i.e. increased arginase activity and accumulation of transcripts encoding for M2 markers). Conversely, leukemia inhibitory factor stimulation had no significant effect in bone marrow-derived macrophage responses to M1-polarizing stimuli (interferon-γ and lipopolysaccharide). Thus, our study provides insight into the transcriptional landscape of leukemia inhibitory factor-treated macrophages, shedding light on its role in lipid metabolism and M2 polarization responses. A better understanding of the regulatory mechanisms governing leukemia inhibitory factor-driven changes might help informing novel therapeutic approaches aiming to reprogram macrophage phenotypes in diseased states (e.g. cancer, atherosclerosis, and infection).

New Posttranslational Modification Lactylation Brings New Inspiration for the Treatment of Rheumatoid Arthritis

Lactic acid (LA) is an essential glycolytic metabolite and energy source in the body, which is present in high levels in the synovial fluid of patients with rheumatoid arthritis (RA) and is a reliable indicator for identifying inflammatory arthritis. LA not only acts as an inflammatory amplifier in RA, recent studies have found that novel posttranslational modification (PTM) lactylation mediated by LA may also play a key role in RA. Single-cell sequencing showed that the RA lactylation score of patients with RA was significantly increased, and core lactylation-promoting genes, including NDUFB3, NGLY1, and other genes, were found to be potential biomarkers of RA. More studies have shown that lactylation can regulate genes in various cells, such as fibroblast-like synoviocytes (FLSs) and macrophages, thus playing a special role in the development and occurrence of autoimmune diseases, neurological diseases, and cancer diseases. In this paper, we review the research on lactylation in RA-related cells and mechanisms and bring new insights into the pathogenesis, diagnosis, and treatment of RA.

Modulation of Tumor-Associated Macrophages to Overcome Immune Suppression in the Hepatocellular Carcinoma Microenvironment

Hepatocellular carcinoma (HCC) is a major global health issue characterized by poor prognosis and complex tumor biology. One of the critical components of the HCC tumor microenvironment (TME) is tumor-associated macrophages (TAMs), which play a pivotal role in modulating tumor growth, immune evasion, and metastasis. Macrophages are divided into two major subtypes: pro-inflammatory M1 and anti-inflammatory M2, both of which may exist in TME with altered function and proportion. The anti-inflammatory M2 macrophages are further subdivided into four distinct immune suppressive subsets. TAMs are generally counted as M2-like macrophages with altered immune suppressive functions that exert a significant influence on both cancer progression and the ability of tumors to escape immune surveillance. Their involvement in modulating immune responses via different mechanisms at the local and systemic levels has made them a key target for therapeutic interventions seeking to enhance treatment outcomes. How TAMs' depletion influences immune responses in cancer is the primary interest in cancer immunotherapies. The purpose of this review is to delve into the recent progress made in TAM-targeting therapies. We will explore the current theories, benefits, and challenges associated with TAMs' depletion or inhibition. The manuscript concludes with future directions and potential implications for clinical practice.

Tumor-derived IL-6 promotes chordoma invasion by stimulating tumor-associated macrophages M2 polarization and TNFα secretion

AIMS

Chordoma is a rare and aggressive bone tumor with high-recurrence and lack of effective treatment methods. Tumor associated macrophages (TAMs) are abundant in tumor microenvironment (TME) and polarize toward M2 in chordoma. It has been observed that the high proportion of M2 cells is associated with chordoma rapid progression. However, the mechanism of TAMs polarization and promotion to tumor progression in chordoma is still unclear. The is an urgent need for further research.

MATERIALS AND METHODS

Flow cytometry and immunohistochemical staining was used to detect the degree of macrophages infiltration in chordoma. A co-culture model of chordoma cells and macrophages was established in vitro to investigate the effects of their interaction on cell function, cytokine secretion, and RNA transcriptome expression.

KEY FINDINGS

In this study, we found M2 macrophage was predominantly abundant immune cell population in chordoma, and its proportion was associated with the degree of bone destruction. We demonstrated that interleukin 6 (IL-6) derived from chordoma cells could induce TAMs polarization by activating STAT3 phosphorylation, and TAMs could enhance chordoma cells migration and invasion through TNFα/NF-κB pathway. The interaction of chordoma cells and TAMs could promote the bone destruction-related factor Cathepsin B (CTSB) and inhibitory immune checkpoints expression. We also confirmed blocking IL-6/STAT3 pathway could significantly attenuate the M2 polarization of TAMs and decrease the secretion of TNFα.

SIGNIFICANCE

This study illustrates the dynamics between chordoma cells and TAMs in promoting chordoma invasion and suggests that IL-6/STAT3 pathway is a potential therapeutic target to reduce TAM-induced chordoma invasion.

Natural and Semisynthetic Immunomodulatory Luakuliide Labdane Diterpenoids

Spectroscopy-guided isolation of extracts of the Tongan marine sponge Hyattella cf. intestinalis (Lamarck, 1814) has resulted in the reisolation of the labdane diterpenoid luakuliide A (1) and one new congener, luakulialactam A (2). In addition to establishing the absolute configuration of 1, synthetic modifications to the luakuliide framework at key positions has created a set of six derivatives (3-8) which were used to interrogate a structure-activity relationship relating to the immunomodulatory effects of luakuliide A. This revealed that compounds 4, 5, and 6, bearing substituted furan motifs, show potent activity in primary macrophages by inhibiting pro-inflammatory cytokine production, while upregulating cellular metabolism and anti-inflammatory IL-10 production at nanomolar concentrations. This is an activity profile consistent with macrophages modulated toward an anti-inflammatory phenotype associated with wound-healing and resolution of inflammation.

Screening and regulatory mechanism exploration of M1 macrophage polarization and efferocytosis-related biomarkers in coronary heart disease

Background

Macrophage polarization and efferocytosis have been implicated in CHD. However, the underlying mechanisms remain elusive. This study aimed to identify CHD-associated biomarkers using transcriptomic data.

Methods

This study examined 74 efferocytosis-related genes (ERGs) and 17 M1 macrophage polarization-related genes (MRGs) across two CHD-relevant datasets, GSE113079 and GSE42148. Differential expression analysis was performed separately on each dataset to identify differentially expressed genes (DEGs1 and DEGs2). The intersection of upregulated and downregulated genes from both sets was then used to define the final DEGs. Subsequently, MRG and ERG scores were calculated within the GSE113079 dataset, followed by weighted gene co-expression network analysis (WGCNA) to identify key module genes. The overlap between these module genes and the DEGs yielded candidate biomarkers, which were further evaluated through machine learning, receiver operating characteristic (ROC) curve analysis, and expression profiling. These biomarkers were subsequently leveraged to explore immune infiltration patterns and to construct a molecular regulatory network. To further validate their expression, quantitative reverse transcriptase PCR (qRT-PCR) was performed on clinical CHD samples, confirming the relevance and expression patterns of these biomarkers in the disease.

Results

A total of 93 DEGs were identified by intersecting the upregulated and downregulated genes from DEGs1 and DEGs2. WGCNA of the MRG and ERG scores identified 15,936 key module genes in the GSE113079 dataset. Machine learning and ROC analysis highlighted four biomarkers: C5orf58, CTAG1A, ZNF180, and IL13RA1. Among these, C5orf58, and ZNF180 were downregulated in CHD cases, while CTAG1A and IL13RA1 was upregulated. qRT-PCR results validated these findings for C5orf58, CTAG1A, ZNF180, and IL13RA1 showed inconsistent expression trends. Immune infiltration analysis indicated IL13RA1 all had a positive correlation with M0 macrophage, while had a negative correlation with. NK cells activated. The molecular regulatory network displayed that GATA2 and YY1 could regulate CTAG1A and ZNF180.

Conclusions

These results suggest that C5orf58, CTAG1A, ZNF180, and IL13RA1 serve as biomarkers linking M1 macrophage polarization and efferocytosis to CHD, providing valuable insights for CHD diagnosis and therapeutic strategies.

Long-term expanded hepatic progenitor cells ameliorate D-GalN/LPS-induced acute liver failure through repolarizing M1 macrophage to M2-Like phenotype via activation of the IL-10/JAK2/STAT3 signaling pathway

Acute liver failure (ALF) is a devastating liver disease characterized by the rapid deterioration of hepatocytes, which causes a series of clinical complications, including hepatic dysfunction, coagulopathy, encephalopathy, and multiorgan failure. Cell-based therapy is a promising alternative as it can bridge patients until their livers regenerate, releasing immunomodulatory molecules to suppress inflammation. This study reports an iPSCs-derived long-term expanded hepatic progenitor cell (LTHepPCs), which can differentiate into hepatocyte-like cells (HLCs) in vivo. When introduced into drug-induced ALF models, LTHepPCs mitigate liver damage by modulating the local immune microenvironment. This is achieved by shifting macrophages/Kupffer cells towards an anti-inflammatory state, resulting in a decrease in the expression of inflammatory cytokines such as TNF-a, IL-1β, and IL-8, and an increase in the expression of anti-inflammatory cytokines such as IL-10 and ARG-1. In vitro co-culturing of THP-1 or mBMDMs with LTHepPCs suggested that LTHepPCs could activate the anti-inflammatory state of macrophages/Kupffer cells via the IL-10/JAK2/STAT3 signaling pathway. Therefore, LTHepPC transplantation is a promising therapy for ALF patients.

Insight into the role of macrophages in periodontitis restoration and development

Periodontitis is one of the chronic diseases that have the greatest impact on human health, and it is associated with several other chronic diseases. Tissue damage associated with periodontitis is often connected with immune response. Immune cells are a crucial component of the human immune system and are directly involved in periodontitis during the inflammatory phase of the disease. Macrophages, as a key component of the immune system, are responsible for defence, antigen presentation and phagocytosis in healthy tissue. They are also closely linked to the development and resolution of periodontitis, through mechanisms such as macrophage polarization, pattern recognition receptors recognition, efferocytosis, and Specialized Pro-resolving Mediators (SPMs) production. Additionally, apoptosis and autophagy are also known to play a role in the recovery of periodontitis. This review aims to investigate the aforementioned mechanisms in more detail and identify novel therapeutic approaches for periodontitis.

Voluntary exercise suppresses inflammation and improves insulin resistance in the arcuate nucleus and ventral tegmental area in mice on a high-fat diet

A high-fat diet (HFD) causes inflammation with an increase in microglial activity in the hypothalamic arcuate nucleus (ARC) and ventral tegmental area (VTA), resulting in insulin resistance in both regions. This leads to a deterioration in glucose and energy metabolism. The effect of voluntary exercise on HFD-induced inflammation in the central nervous system (CNS) remains unclear. To clarify the effects of voluntary exercise on the CNS, 8-week-old male C57BL6 mice were fed a chow diet (CHD) or HFD for 4 weeks; each group was further divided into running exercise (EX+) on a wheel and no exercise (EX-) groups. The expression of the inflammatory cytokine, tumor necrosis factor alpha (TNFα), in the ARC and VTA was significantly increased in the HFD/EX- group, with an increase of microglial activity noted, compared to the CHD/EX- group. The expression of TNFα was significantly suppressed, with a decrease of microglial activity, in the HFD/EX+ compared to HFD/EX- group. Insulin resistance in the ARC and VTA was improved with the suppression of TNFα expression. The HFD/EX- group showed significant weight gain and impaired glucose metabolism compared to the CHD/EX- group. The HFD/EX+ group showed an improvement in glucose and energy metabolism compared to the HFD/EX- group. In addition, voluntary wheel running suppressed HFD-induced inflammation in the ARC, with a decrease in microglial activity observed independently of weight changes. Our data suggest that voluntary exercise prevents obesity and improves glucose metabolism by suppressing inflammation in the ARC and VTA under HFD conditions.

Macrophage Polarization: A Novel Target and Strategy for Pathological Scarring

BACKGROUND

Abnormal scarring imposes considerable challenges and burdens on the lives of patients and healthcare system. Macrophages at the wound site are found to be of great concern to overall wound healing. There have been many studies indicating an inextricably link between dysfunctional macrophages and fibrotic scars. Macrophages are not only related to pathogen destruction and phagocytosis of apoptotic cells, but also involved in angiogenesis, keratinization and collagen deposition. These abundant cell functions are attributed to specific heterogeneity and plasticity of macrophages, which also add an extra layer of complexity to correlational researches.

METHODS

This article summarizes current understanding of macrophage polarization in scar formation and several prevention and treatment strategies on pathological scarring related to regulation of macrophage behaviors by utilizing databases such as PubMed, Google Scholar and so on.

RESULTS

There are many studies proving that macrophages participate in the course of wound healing by converting their predominant phenotype. The potential of macrophages in managing hypertrophic scars and keloid lesions have been underscored.

CONCLUSION

Macrophage polarization offers new prevention strategies for pathological scarring. Learning about and targeting at macrophages may be helpful in achieving optimum wound healing.

Contribution of macrophage polarization in bone metabolism: A literature review

Macrophage polarization divides macrophages into two main cell subpopulations, classically and alternatively activated macrophages (M1 and M2, respectively). M1 polarization promotes osteoclastogenesis, while M2 polarization promotes osteogenesis. The physiological homeostasis of bone metabolism involves a high dynamic balance between osteoclastic-mediated bone resorption and formation. Reportedly, M1/M2 imbalance causes the onset and persistence of inflammation-related bone diseases. Therefore, understanding the research advances in functions and roles of macrophages in such diseases will provide substantial guidance for improved treatment of bone diseases. In this review, we underscore and summarize the research advances in macrophage polarization, and bone-related diseases, such as rheumatoid arthritis, osteoarthritis, and osteoporosis, over the last 5 years. Our findings showed that targeting macrophages and balancing macrophage polarization can effectively reduce inflammation and decrease bone destruction while promoting bone formation and vascular repair. These results indicate that regulating macrophage and macrophage polarization to restore homeostasis is a prospective approach for curing bone-related diseases.

Macrophage polarization in human periapical lesions in relation to histopathological diagnosis, clinical features and lesion volume: An ex vivo study

AIM

To evaluate M1 and M2 macrophage polarization in radicular cysts and periapical granulomas through an immunohistochemical analysis and the correlation between macrophage polarization and histopathological diagnosis, clinical characteristics and lesion volume using cone-beam computed tomography.

METHODOLOGY

Periapical biopsies diagnosed as radicular cysts (n = 52) and periapical granulomas (n = 51) were analysed by immunohistochemical method. Teeth with periapical lesion with no history of root canal treatment (primary lesion) and lesions persistent to root canal treatment (persistent lesions) were included. Pathological diagnosis, patients' age, gender and clinical characteristics were obtained from treatment records. A cone-beam computed tomographic periapical volume index (CBCTPAVI) score was assigned to each periapical lesion based on the volume of the lesion. Immuno-expressions of CD68 and CD163 were quantified. The CD68/CD163 ratio was adopted to represent M1 or M2 macrophage polarization. Mann-Whitney U test was used to determine the different CD68/CD163 ratio between groups of radicular cyst and periapical granuloma. Spearman's correlation test was performed to assess the correlation between the CD68/CD163 ratio and lesion volume and CBCTPAVI score.

RESULTS

Radicular cysts and periapical granulomas had CD68/CD163 median of 2.05 (IQR = 1.33) and 1.26 (IQR = 0.81), respectively. A significantly higher CD68/CD163 ratio was observed in radicular cysts (p < .001). In contrast, periapical granulomas had significantly lower median of CD68/CD163 ratio. Larger lesions had a higher median of CD68/CD163 ratio, while smaller lesions had lower median of CD68/CD163 ratio (p = .007, rs = .262). CD68/CD163 ratio was significantly correlated with the CBCTPAVI score in the overall periapical lesions (p = .002, rs = .306). The higher CD68/CD163 ratio in larger lesions indicated a higher degree of M1 polarization compared to smaller lesions. Regarding the pathological diagnosis, there was a significant positive correlation between CBCTPAVI score and CD68/CD163 ratio in periapical granulomas (p < .001, rs = .453), whereas the negative correlation was observed for radicular cysts (p < .001, rs = -.471).

CONCLUSIONS

Periapical granulomas are characterized by a M2-dominant macrophage polarization, while radicular cysts have significantly higher M1 macrophages. The higher degree of M1 macrophage polarization was significantly correlated with larger volume and higher CBCTPAVI scores of overall periapical lesion and periapical granuloma.

Association of the atherogenic index of plasma and modified triglyceride-glucose indices with digestive diseases among middle-aged and older population in China

BACKGROUND

Previous studies have shown that metabolic imbalances contribute to digestive diseases. This study aimed to investigate the relationship of the atherogenic index of plasma (AIP) and modified triglyceride-glucose (TyG) indices with digestive diseases.

METHODS

We recruited participants aged 45 years or older from the China Health and Retirement Longitudinal Study (CHARLS, 2011 - 2020). The indices assessed included AIP, TyG, triacylglycerol glucose-waist circumference (TyG-WC), the triacylglycerol glucose-waist-to-height ratio (TyG-WHtR), and the triacylglycerol glucose-body mass index (TyG-BMI). We used logistic regression and restricted cubic spline (RCS) analyses to examine the associations between these indices and the incidence of digestive diseases.

RESULTS

A total of 4,453 participants were included in our analysis, 53.3% of whom were female, with an average age of 60 years. The incidence of digestive diseases in middle-aged and older adults was 6.18%. Compared with those in the lowest tertile group, the odds ratios (ORs) with 95% confidence intervals (CIs) for digestive diseases in the highest tertile for AIP, TyG, TyG-WC, TyG-WHtR, and TyG-BMI were 1.452 (1.07-1.972), 1.193 (0.873-1.631), 1.349 (1.044-1.743), 1.5 (1.089-2.068), and 1.312 (0.956-1.799), respectively. Sensitivity analyses confirmed the robustness of the correlations between these indices and digestive diseases.

CONCLUSION

Our study revealed that the AIP, TyG-WC, and TyG-WHtR were independently associated with the incidence of digestive diseases. These findings highlight the importance of considering and optimizing metabolic factors in management strategies for digestive diseases.

Pathogenesis and Key Cells in Allergic Rhinitis

BACKGROUND

Allergic rhinitis (AR) is one of the most common chronic diseases worldwide, with prevalence rates as high as 50% in high-income countries. Patients with AR often have symptoms such as runny nose, itchy nose, nasal congestion, sneezing, and signs of edema and pallor of the nasal mucosa, and these pathologies have a major impact on the patient's learning, sleep, and quality of life, often resulting in significant pain and a huge economic burden for the patient.

SUMMARY

Among the current treatments for AR, immunotherapy is able to achieve satisfactory clinical outcomes. This shows the importance of immune cells in AR. However, current therapies do not provide a complete cure for AR. The reason for this is that current research on AR focuses on the mechanism of Th1 and Th2 immune cells in AR, ignoring the role of other key cells in AR.

KEY MESSAGES

Group 2 innate lymphoid cells, B cells, T cells, and macrophages can play a role in the pathogenesis of AR by producing appropriate cytokines and mediating the inflammatory response. M2 macrophages can promote Th2 cells and eosinophils in AR to enhance the type 2 inflammatory response and further promote AR.

Extracellular Vesicles in Viral Liver Diseases

Extracellular vesicles (EVs) are bilayer vesicles released by cells in the microenvironment of the liver including parenchymal and non-parenchymal cells. They are the third important mechanism in the communications between cells, besides the secretion of cytokines and chemokines and the direct cell-to-cell contact. The aim of this review is to discuss the important role of EVs in viral liver disease, as there is increasing evidence that the transportation of viral proteins, all types of RNA, and viral particles including complete virions is implicated in the pathogenesis of both viral cirrhosis and viral-related hepatocellular carcinoma. The biogenesis of EVs is discussed and their role in the pathogenesis of viral liver diseases is presented. Their use as diagnostic and prognostic biomarkers is also analyzed. Most importantly, the significance of possible novel treatment strategies for liver fibrosis and hepatocellular carcinoma is presented, although available data are based on experimental evidence and clinical trials have not been reported.

Roles of macrophages in lupus nephritis

LN is a serious complication of systemic lupus erythematosus (SLE), affecting up to 60% of patients with SLE and may lead to end-stage renal disease (ESRD). Macrophages play multifaceted roles in the pathogenesis of LN, including clearance of immune complexes, antigen presentation, regulation of inflammation, and tissue repair. Macrophages are abundant in the glomeruli and tubulointerstitium of LN patients and are positively correlated with serum creatinine levels and the severity of renal pathology. It has been shown that the infiltration of macrophages is closely associated with several clinical indicators, such as serum creatinine and complement C3 levels, anti-dsDNA antibody titers, Austin score, interstitial fibrosis and renal tubular atrophy. Moreover, cytokines expressed by macrophages were upregulated at LN onset and downregulated after remission, suggesting that macrophages may serve as markers of LN pathogenesis and remission. Therapies targeting macrophages have been shown to alleviate LN. There are two main types of macrophages in the kidney: kidney-resident macrophages (KRMs) and monocyte-derived macrophages (MDMs). KRMs and MDMs play different pathological roles in LN, with KRMs promoting leukocyte recruitment at sites of inflammation by expressing monocyte chemokines, while MDMs may exacerbate autoimmune responses by presenting immune complex antigens. Macrophages exhibit high plasticity and can differentiate into various phenotypes in response to distinct environmental stimuli. M1 (proinflammatory) macrophages are linked to the progression of active SLE, whereas the M2 (anti-inflammatory) phenotype is observed during the remission phase of LN. The polarization of macrophages in LN can be manipulated through multiple pathways, such as the modulation of signaling cascades including TLR 2/1, S1P, ERS, metabolic reprogramming, and HMGB1. This paper provides a comprehensive overview of the role of macrophages in the progression of lupus nephritis (LN), and elucidates how these cells and their secretory products function as indicators and therapeutic targets for the disease in the context of diagnosis and treatment of LN.

Microneedle patches incorporating zinc-doped mesoporous silica nanoparticles loaded with betamethasone dipropionate for psoriasis treatment

Treating psoriasis presents a major clinical challenge because of the limitations associated with traditional topical glucocorticoid therapy. This study introduced a drug delivery system utilizing zinc-doped mesoporous silica nanoparticle (Zn-MSN) and microneedle (MN), designed to enhance drug utilization for prolonged anti-inflammatory and anti-itch effects. The MN system facilitated the transdermal delivery of betamethasone dipropionate (BD), allowing its slow release. The BD@Zn-MSN-MN system promoted the polarization of macrophages towards the anti-inflammatory M2 phenotype, achieving superior anti-inflammatory effects compared to the clinically used BD cream. Additionally, this study demonstrated that BD@Zn-MSN-MN could further alleviate itching in psoriasis-afflicted mice by decreasing the excitability of the transient receptor potential vanilloid V1 (TRPV1) ion channel positive neurons and reducing the release of calcitonin gene-related peptide (CGRP) in the dorsal root ganglion (DRG). These findings offer new insights and effective therapeutic options for the future design of transdermal drug delivery for psoriasis.

Tumor-associated macrophages in bladder cancer: roles and targeted therapeutic strategies

Bladder cancer (BC) is the ninth most common and "expensive" cancer in the world. Despite the availability of various treatment modalities such as chemotherapy, immunotherapy and surgery, the overall survival rate of patients with advanced bladder cancer remains low. As one of the most abundant infiltrating immune cells in bladder cancer, tumor-associated macrophages (TAMs) play an important role in the development of BC and in the standard regimen of intravesical BCG therapy. Targeting TAMs have achieved excellent results in clinical trials for a variety of other cancers, but few studies have been conducted for bladder cancer. Further exploration is still needed to develop TAM-related therapeutic strategies for BC treatment, which are expected to improve the therapeutic efficacy and life quality of patients. This review summarizes the relationship between TAMs in bladder cancer and disease staging, evolution, patient prognosis, and treatment outcome. Several potential TAM targets in BC are also pointed, which may help to inhibit tumor-promoting TAMs and provide new therapeutic approaches for advanced BC.

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.

Mechanisms and treatment of atherosclerosis: focus on macrophages

Macrophages are the basic mediators and coordinators of various types of chronic inflammation and play a crucial role in the formation and development of atherosclerosis (AS). In the complex microenvironment of atherosclerotic plaques, macrophages of different sources are exposed to different signal stimuli and thus polarized into various subpopulations. Various types of macrophages with predominantly M1 and M2 phenotypes also play different regulatory roles in the initiation and progression of AS. Lipid-lowering drugs, mainly statins, are widely used in clinical practice, but the adverse reactions are obvious and there is a lack of personalized treatment. Emerging targeted macrophage and Traditional Chinese medicine (TCM)-related therapies can regulate the cellular microenvironment, inhibit the polarization of M1 macrophages, and promote the activation of M2 macrophages, providing new ideas for the prevention and treatment of AS.

Targeting Macrophage Phenotype for Treating Heart Failure: A New Approach

Heart failure (HF) is a disease with high morbidity and mortality rates worldwide and significantly affects human health. Currently, the treatment options for HF are limited, and there is an urgent need to discover new therapeutic targets and strategies. Macrophages are innate immune cells involved in the development of HF. They play a crucial role in maintaining cardiac homeostasis and regulating cardiac stress. Recently, macrophages have received increasing attention as potential targets for treating HF. With the improvement of technological means, the study of macrophages in HF has made great progress. This article discusses the biological functions of macrophage phagocytosis, immune response, and tissue repair. The polarization, pyroptosis, autophagy, and apoptosis are of macrophages, deeply involved in the pathogenesis of HF. Modulation of the phenotypic changes of macrophages can improve immune-inflammation, myocardial fibrosis, energy metabolism, apoptosis, and angiogenesis in HF.

Mitochondrial metabolism regulated macrophage phenotype in myocardial infarction

Cardiovascular disease (CVD) remains the leading cause of death worldwide, with myocardial infarction (MI) being the primary contributor to mortality and disability associated with CVD. Reperfusion therapies are widely recognized as effective strategies for treating MI. However, while intended to restore blood flow, the reperfusion processes paradoxically initiate a series of pathophysiological events that worsen myocardial injury, resulting in ischemia-reperfusion (I/R) injury. Therefore, there is a pressing need for new treatment strategies to reduce the size of MI and enhance cardiac function post-infarction. Macrophages are crucial for maintaining homeostasis and mitigating undesirable remodeling following MI. Extensive research has established a strong link between cellular metabolism and macrophage function. In the context of MI, macrophages undergo adaptive metabolic reprogramming to mount an immune response. Moreover, mitochondrial metabolism in macrophages is evident, leading to significant changes in their metabolism. Therefore, we need to delve deeper into summarizing and understanding the relationship and role between mitochondrial metabolism and macrophage phenotype, and summarize existing treatment methods. In this review, we explore the role of mitochondria in shaping the macrophage phenotype and function. Additionally, we summarize current therapeutic strategies aimed at modulating mitochondrial metabolism of macrophages, which may offer new insights treating of MI.

Transforming growth factor-β micro-environment mediated immune cell functions in cervical cancer

Propensity to develop cervical cancer (CC) in human papilloma virus (HPV) infected individual could potentially involve the impaired immune functioning. Several stages of HPV surveillance by immune cells in tumor micro-environment (TME) is regulated mainly by transforming growth factor-beta (TGF-β) and is crucial for the establishment of CC. The role of TGF-β in the initiation and progression of CC is very complex and involve different suppressor of mothers against decapentaplegic homolog (SMAD) dependent and SMAD independent signaling mechanism(s). This review summarizes the handling of HPV by immune cells such as T lymphocytes, B lymphocytes, natural killer cells (NK), dendritic cells (DC), monocytes, macrophages, myeloid derived suppressor cells (MDSC) and their regulation by TGF-β. The hijack mechanisms adapted by HPV to evade this surveillance process is discussed. Biomarkers indicating the stages of CC and immune checkpoints that can be targeted for improved outcome are included for immune-based theragnostics. This review also addresses the direct actions of TGF-β on CC cells and tumor/immune cell interactions. Therapies focused on targeting TGF-β using small molecule inhibitors, monoclonal antibodies and TGF-β chimeric antigen receptor (CAR)T cells are collated to understand the current strategies related to TGF-β in the management of CC.

Periostin+ myeloid cells improved long bone regeneration in a mechanosensitive manner

Myeloid cells are pivotal in the inflammatory and remodeling phases of fracture repair. Here, we investigate the effect of periostin expressed by myeloid cells on bone regeneration in a monocortical tibial defect (MTD) model. In this study, we show that periostin is expressed by periosteal myeloid cells, primarily the M2 macrophages during bone regeneration. Knockout of periostin in myeloid cells reduces cortical bone thickness, disrupts trabecular bone connectivity, impairs repair impairment, and hinders M2 macrophage polarization. Mechanical stimulation is a regulator of periostin in macrophages. By activating transforming growth factor-β (TGF-β), it increases periostin expression in macrophages and induces M2 polarization. This mechanosensitive effect also reverses the delayed bone repair induced by periostin deficiency in myeloid cells by strengthening the angiogenesis-osteogenesis coupling. In addition, transplantation of mechanically conditioned macrophages into the periosteum over a bone defect results in substantially enhanced repair, confirming the critical role of macrophage-secreted periostin in bone repair. In summary, our findings suggest that mechanical stimulation regulates periostin expression and promotes M2 macrophage polarization, highlighting the potential of mechanically conditioned macrophages as a therapeutic strategy for enhancing bone repair.

Mechanism of macrophages in gout: Recent progress and perspective

Gout represents an autoinflammatory disorder instigated by monosodium urate crystals. Its primary manifestation involves the recruitment of diverse immune cell populations, including neutrophils and macrophages. Macrophages assume a pivotal role in the initiation of acute gouty inflammation and subsequent inflammatory cascades. However, recent investigations have revealed that the impact of macrophages on gout is nuanced, extending beyond a solely detrimental influence. Macrophages, characterized by different subtypes, exhibit distinct functionalities that either contribute to the progression or regression of gout. A strategy aimed at modulating macrophage polarization, rather than merely inhibiting inflammation, holds promise for enhancing the efficacy of acute gout treatment. This review centres on elucidating potential mechanisms underlying macrophage polarization in the onset and resolution of gouty inflammation, offering novel insights into the immune equilibrium of macrophages in the context of gout.

Macrophages as Potential Therapeutic Targets in Acute Myeloid Leukemia

Acute myeloid leukemia (AML) is a heterogenous malignant hemopathy, and although new drugs have emerged recently, current treatment options still show limited efficacy. Therapy resistance remains a major concern due to its contribution to treatment failure, disease relapse, and increased mortality among patients. The underlying mechanisms of resistance to therapy are not fully understood, and it is crucial to address this challenge to improve therapy. Macrophages are immune cells found within the bone marrow microenvironment (BMME), of critical importance for leukemia development and progression. One defining feature of macrophages is their plasticity, which allows them to adapt to the variations in the microenvironment. While this adaptability is advantageous during wound healing, it can also be exploited in cancer scenarios. Thus, clinical and preclinical investigations that target macrophages as a therapeutic strategy appear promising. Existing research indicates that targeting macrophages could enhance the effectiveness of current AML treatments. This review addresses the importance of macrophages as therapeutic targets including relevant drugs investigated in clinical trials such as pexidartinib, magrolimab or bexmarilimab, but also provides new insights into lesser-known therapies, like macrophage receptor with a collagenous structure (MACRO) inhibitors and Toll-like receptor (TLR) agonists.

Metabolic regulation of the immune system in health and diseases: mechanisms and interventions

Metabolism, including glycolysis, oxidative phosphorylation, fatty acid oxidation, and other metabolic pathways, impacts the phenotypes and functions of immune cells. The metabolic regulation of the immune system is important in the pathogenesis and progression of numerous diseases, such as cancers, autoimmune diseases and metabolic diseases. The concept of immunometabolism was introduced over a decade ago to elucidate the intricate interplay between metabolism and immunity. The definition of immunometabolism has expanded from chronic low-grade inflammation in metabolic diseases to metabolic reprogramming of immune cells in various diseases. With immunometabolism being proposed and developed, the metabolic regulation of the immune system can be gradually summarized and becomes more and more clearer. In the context of many diseases including cancer, autoimmune diseases, metabolic diseases, and many other disease, metabolic reprogramming occurs in immune cells inducing proinflammatory or anti-inflammatory effects. The phenotypic and functional changes of immune cells caused by metabolic regulation further affect and development of diseases. Based on experimental results, targeting cellular metabolism of immune cells becomes a promising therapy. In this review, we focus on immune cells to introduce their metabolic pathways and metabolic reprogramming, and summarize how these metabolic pathways affect immune effects in the context of diseases. We thoroughly explore targets and treatments based on immunometabolism in existing studies. The challenges of translating experimental results into clinical applications in the field of immunometabolism are also summarized. We believe that a better understanding of immune regulation in health and diseases will improve the management of most diseases.

Mannose and Lactobionic Acid in Nasal Vaccination: Enhancing Antigen Delivery via C-Type Lectin Receptors

BACKGROUND/OBJECTIVES

Nasal vaccines are a promising strategy for enhancing mucosal immune responses and preventing diseases at mucosal sites by stimulating the secretion of secretory IgA, which is crucial for early pathogen neutralization. However, designing effective nasal vaccines is challenging due to the complex immunological mechanisms in the nasal mucosa, which must balance protection and tolerance against constant exposure to inhaled pathogens. The nasal route also presents unique formulation and delivery hurdles, such as the mucous layer hindering antigen penetration and immune cell access.

METHODS

This review focuses on cutting-edge approaches to enhance nasal vaccine delivery, particularly those targeting C-type lectin receptors (CLRs) like the mannose receptor and macrophage galactose-type lectin (MGL) receptor. It elucidates the roles of these receptors in antigen recognition and uptake by antigen-presenting cells (APCs), providing insights into optimizing vaccine delivery.

RESULTS

While a comprehensive examination of targeted glycoconjugate vaccine development is outside the scope of this study, we provide key examples of glycan-based ligands, such as lactobionic acid and mannose, which can selectively target CLRs in the nasal mucosa.

CONCLUSIONS

With the rise of new viral infections, this review aims to facilitate the design of innovative vaccines and equip researchers, clinicians, and vaccine developers with the knowledge to enhance immune defenses against respiratory pathogens, ultimately protecting public health.

In vitro immunomodulatory effects of Caryocar villosum oil on murine macrophages

Macrophages undergo activation in response to multiple stimuli, including pathogens, growth factors and natural products. The inflammatory response and oxidative stress play critical roles in such macrophage activation. Some natural products reportedly promote immunoregulatory effects and the control of macrophage activation. Caryocar villosum (Cv), a native amazon plant, contains compounds that are an important source of molecules capable of macrophage activation. Herein, we demonstrate the immunomodulatory effects of oil obtained from Caryocar villosum (CvO) on macrophages. Macrophages were treated with varying concentrations of CvO, and resulting cellular morphological and functional changes were evaluated, including the production of nitric oxide (NO), reactive oxygen species (ROS), cytokines and phagocytic activity. Treatment of cells with 50 and 100 μg/mL CvO induced morphological and physiological alterations in the macrophages, such as increased cell surface and phagocytic activity. Additionally, treatment increased the productions of inflammatory cytokines (INF-γ, TNF-α, IL-6) and anti-inflammatory cytokines (IL-17 and IL-10) by macrophages, and significantly decreased ROS levels. In conclusion, these data suggest that, due to molecular diversity, CvO promoted an immunomodulatory effect on macrophages, mediated by an increased production of cytokines, and inhibition of ROS generation and phagocytic activity. Thus, CvO presents potential as a therapeutic agent for the treatment of inflammatory and non-inflammatory diseases.

Macrophages in the inflammatory response to endotoxic shock

BACKGROUND

Endotoxic shock, particularly prevalent in intensive care units, represents a significant medical challenge. Endotoxin, upon invading the host, triggers intricate interactions with the innate immune system, particularly macrophages. This activation leads to the production of inflammatory mediators such as tumor necrosis factor-alpha, interleukin-6, and interleukin-1-beta, as well as aberrant activation of the nuclear factor-kappa-B and mitogen-activated protein kinase signaling pathways.

OBJECTIVE

This review delves into the intricate inflammatory cascades underpinning endotoxic shock, with a particular focus on the pivotal role of macrophages. It aims to elucidate the clinical implications of these processes and offer insights into potential therapeutic strategies.

RESULTS

Macrophages, central to immune regulation, manifest in two distinct subsets: M1 (classically activated subtype) macrophages and M2 (alternatively activated subtype) macrophages. The former exhibit an inflammatory phenotype, while the latter adopt an anti-inflammatory role. By modulating the inflammatory response in patients with endotoxic shock, these macrophages play a crucial role in restoring immune balance and facilitating recovery.

CONCLUSION

Macrophages undergo dynamic changes within the immune system, orchestrating essential processes for maintaining tissue homeostasis. A deeper comprehension of the mechanisms governing macrophage-mediated inflammation lays the groundwork for an anti-inflammatory, targeted approach to treating endotoxic shock. This understanding can significantly contribute to the development of more effective therapeutic interventions.

Macrophage polarization regulation shed lights on immunotherapy for CaOx kidney stone disease

Kidney stone disease (KSD) is a major public health concern associated with high morbidity and recurrence, places a significant burden on the health care system worldwide. Calcium oxalate (CaOx) alone or a mixture of CaOx and calcium phosphate stones accounting for more than 80 % of cases. However, beyond surgical removal, the prevention and reduction of recurrence of CaOx kidney stones have always been a challenge. Given that macrophages are traditional innate immune cells that play critical roles in the clearance of pathogens and the maintenance of tissue homeostasis, which have gained more and more interests in nephrolithiasis. Several studies recently clearly demonstrated that M2-macrophage could reduce the renal calcium oxalate (CaOx) crystal acumination, and provide premise insights and therapeutic options for KSD by modulating the macrophage phenotypes. However, the mechanism of macrophage-polarization regulation and that effects on kidney stone prevention and treatments are far from clear. Here, we comprehensively reviewed the literatures related to cytokines, epigenetic modifications and metabolic reprograming of macrophage in CaOx kidney stone disease, aimed to provide better understandings on macrophage polarization regulation as well as its potential clinical applications in CaOx kidney stone disease treatments and prevention.

Utilising an in silico model to predict outcomes in senescence-driven acute liver injury

Currently liver transplantation is the only treatment option for liver disease, but organ availability cannot meet patient demand. Alternative regenerative therapies, including cell transplantation, aim to modulate the injured microenvironment from inflammation and scarring towards regeneration. The complexity of the liver injury response makes it challenging to identify suitable therapeutic targets when relying on experimental approaches alone. Therefore, we adopted a combined in vivo-in silico approach and developed an ordinary differential equation model of acute liver disease able to predict the host response to injury and potential interventions. The Mdm2fl/fl mouse model of senescence-driven liver injury was used to generate a quantitative dynamic characterisation of the key cellular players (macrophages, endothelial cells, myofibroblasts) and extra cellular matrix involved in liver injury. This was qualitatively captured by the mathematical model. The mathematical model was then used to predict injury outcomes in response to milder and more severe levels of senescence-induced liver injury and validated with experimental in vivo data. In silico experiments using the validated model were then performed to interrogate potential approaches to enhance regeneration. These predicted that increasing the rate of macrophage phenotypic switch or increasing the number of pro-regenerative macrophages in the system will accelerate the rate of senescent cell clearance and resolution. These results showcase the potential benefits of mechanistic mathematical modelling for capturing the dynamics of complex biological systems and identifying therapeutic interventions that may enhance our understanding of injury-repair mechanisms and reduce translational bottlenecks.

Integrated metabolic-transcriptomic network identifies immunometabolic modulations in human macrophages

Macrophages exhibit diverse phenotypes and respond flexibly to environmental cues through metabolic remodeling. In this study, we present a comprehensive multi-omics dataset integrating intra- and extracellular metabolomes with transcriptomic data to investigate the metabolic impact on human macrophage function. Our analysis establishes a metabolite-gene correlation network that characterizes macrophage activation. We find that the concurrent inhibition of tryptophan catabolism by IDO1 and IL4I1 inhibitors suppresses the macrophage pro-inflammatory response, whereas single inhibition leads to pro-inflammatory activation. We find that a subset of anti-inflammatory macrophages activated by Fc receptor signaling promotes glycolysis, challenging the conventional concept of reduced glycolysis preference in anti-inflammatory macrophages. We demonstrate that cholesterol accumulation suppresses macrophage IFN-γ responses. Our integrated network enables the discovery of immunometabolic features, provides insights into macrophage functional metabolic reprogramming, and offers valuable resources for researchers exploring macrophage immunometabolic characteristics and potential therapeutic targets for immune-related disorders.

The Systemic Effect of Ischemia Training and Its Impact on Bone Marrow-Derived Monocytes

OBJECTIVE

Monocytes are innate immune cells that play a central role in inflammation, an essential component during neovascularization. Our recent publication demonstrated that ischemia training by 24 h unilateral occlusion of the femoral artery (FA) can modify bone marrow-derived monocytes (BM-Mono), allowing them to improve collateral remodeling in a mouse model of hindlimb ischemia. Here, we expand on our previous findings, investigating a potential systemic effect of ischemia training and how this training can impact BM-Mono.

METHODS AND RESULTS

BM-Mono from mice exposed to ischemia training (24 h) or Sham (same surgical procedure without femoral artery occlusion-ischemia training) procedures were used as donors in adoptive transfer experiments where recipients were subjected to hindlimb ischemia. Donor cells were divided corresponding to the limb from which they were isolated (left-limb previously subjected to 24 h ischemia and right-contralateral limb). Recipients who received 24 h ischemic-trained monocytes isolated from either limb had remarkable blood flow recovery compared to recipients with Sham monocytes (monocytes isolated from Sham group-no ischemia training). Since these data suggested a systemic effect of ischemic training, circulating extracellular vesicles (EVs) were investigated as potential players. EVs were isolated from both groups, 24 h-trained and Sham, and the former showed increased expression of histone deacetylase 1 (HDAC1), which is known to downregulate 24-dehydrocholesterol reductase (Dhcr24) gene expression. Since we previously revealed that ischemia training downregulates Dhcr24 in BM-Mono, we incubated EVs from 24 h-trained and Sham groups with wild-type (WT) BM-Mono and demonstrated that WT BM-Mono incubated with 24 h-trained EVs had lower gene expression of Dhcr24 and an HDAC1 inhibitor blunted this effect. Next, we repeated the adoptive transfer experiment using Dhcr24 KO mice as donors of BM-Mono for WT mice subjected to hindlimb ischemia. Recipients who received Dhcr24 KO BM-Mono had greater limb perfusion than those who received WT BM-Mono. Further, we focused on the 24 h-trained monocytes (which previously showed downregulation of Dhcr24 gene expression and higher desmosterol) to test the expression of a few genes downstream of the desmosterol pathway, confirm the Dhcr24 protein level and assess its differentiation in M2-like macrophage phenotype. We found that 24 h-trained BM-Mono had greater expression of key genes in the desmosterol pathway, such as liver X receptors (LXRs) and ATP-binding cassette transporter (ABCA1), and we confirmed low protein expression of Dhcr24. Further, we demonstrated that ischemic-trained BM-Mono polarized towards an anti-inflammatory M2 macrophage phenotype. Finally, we demonstrated that 24 h-trained monocytes adhere less to endothelial cells, and the same pattern was shown by WT BM-Mono treated with Dhcr24 inhibitor.

CONCLUSIONS

Ischemia training leads to a systemic effect that, at least in part, involves circulating EVs and potential epigenetic modification in BM-Mono. These ischemic-trained BM-Mono demonstrated an anti-inflammatory phenotype towards M2 macrophage differentiation and less ability to adhere to endothelial cells, which is associated with the downregulation of Dhcr24 in those cells. These data together suggest that Dhcr24 might be an important target within monocytes to improve the outcomes of hindlimb ischemia.

The Contribution of Macrophage Plasticity to Inflammatory Arthritis and Their Potential as Therapeutic Targets

Inflammatory arthritis are common chronic inflammatory autoimmune diseases characterised by progressive, destructive inflammation of the joints leading to a loss of function and significant comorbidities; importantly, there are no cures and only 20% of patients achieve drug-free remission for over 2 years. Macrophages play a vital role in maintaining homeostasis, however, under the wrong environmental cues, become drivers of chronic synovial inflammation. Based on the current "dogma", M1 macrophages secrete pro-inflammatory cytokines and chemokines, promoting tissue degradation and joint and bone erosion which over time lead to accelerated disease progression. On the other hand, M2 macrophages secrete anti-inflammatory mediators associated with wound healing, tissue remodelling and the resolution of inflammation. Currently, four subtypes of M2 macrophages have been identified, namely M2a, M2b, M2c and M2d. However, more subtypes may exist due to macrophage plasticity and the ability for repolarisation. Macrophages are highly plastic, and polarisation exists as a continuum with diverse intermediate phenotypes. This plasticity is achieved by a highly amenable epigenome in response to environmental stimuli and shifts in metabolism. Initiating treatment during the early stages of disease is important for improved prognosis and patient outcomes. Currently, no treatment targeting macrophages specifically is available. Such therapeutics are being investigated in ongoing clinical trials. The repolarisation of pro-inflammatory macrophages towards the anti-inflammatory phenotype has been proposed as an effective approach in targeting the M1/M2 imbalance, and in turn is a potential therapeutic strategy for IA diseases. Therefore, elucidating the mechanisms that govern macrophage plasticity is fundamental for the success of novel macrophage targeting therapeutics.

Macrophage fate: to kill or not to kill?

Macrophages are dynamic innate immune cells that either reside in tissue, serving as sentinels, or recruited as monocytes from bone marrow into inflamed and infected tissue. In response to cues in the tissue microenvironment (TME), macrophages polarize on a continuum toward M1 or M2 with diverse roles in progression and resolution of disease. M1-like macrophages exhibit proinflammatory functions with antimicrobial and anti-tumorigenic activities, while M2-like macrophages have anti-inflammatory functions that generally resolve inflammatory responses and orchestrate a tissue healing process. Given these opposite phenotypes, proper spatiotemporal coordination of macrophage polarization in response to cues within the TME is critical to effectively resolve infectious disease and regulate wound healing. However, if this spatiotemporal coordination becomes disrupted due to persistent infection or dysregulated coagulation, macrophages' inappropriate response to these cues will result in the development of diseases with clinically unfavorable outcomes. Since plasticity and heterogeneity are hallmarks of macrophages, they are attractive targets for therapies to reprogram toward specific phenotypes that could resolve disease and favor clinical prognosis. In this review, we discuss how basic science studies have elucidated macrophage polarization mechanisms in TMEs during infections and inflammation, particularly coagulation. Therefore, understanding the dynamics of macrophage polarization within TMEs in diseases is important in further development of targeted therapies.

Chronic NOD2 stimulation by MDP confers protection against parthanatos through M2b macrophage polarization in RAW264.7 cells

Innate immune cells show enhanced responsiveness to secondary challenges after an initial non-related stimulation (Trained Innate Immunity, TII). Acute NOD2 activation by Muramyl-Dipeptide (MDP) promotes TII inducing the secretion of pro-inflammatory mediators, while a sustained MDP-stimulation down-regulates the inflammatory response, restoring tolerance. Here we characterized in-vitro the response of murine macrophages to lipopolysaccharide (LPS) challenge under NOD2-chronic stimulation. RAW264.7 cells were trained with MDP (1 μg/ml, 48 h) and challenged with LPS (5 μg/ml, 24 h). Trained cells formed multinucleated giant cells with increased phagocytosis rates compared to untrained/challenged cells. They showed a reduced mitochondrial activity and a switch to aerobic glycolysis. TNF-α, ROS and NO were upregulated in both trained and untrained cultures (MDP+, MDP- cells, p > 0.05); while IL-10, IL-6 IL-12 and MHCII were upregulated only in trained cells after LPS challenge (MDP + LPS+, p < 0.05). A slight upregulation in the expression of B7.2 was also observed in this group, although differences were not statistically significant. MDP-training induced resistance to LPS challenge (p < 0.01). The relative expression of PARP-1 was downregulated after the LPS challenge, which may contribute to the regulatory milieu and to the innate memory mechanisms exhibited by MDP-trained cells. Our results demonstrate that a sustained MDP-training polarizes murine macrophages towards a M2b profile, inhibiting parthanatos. These results may impact on the development of strategies to immunomodulate processes in which inflammation should be controlled.