M2 Macrophages Research Articles

Sex-dependent modulation of caerulein-induced acute pancreatitis in C57BL/6J mice.

Acute pancreatitis (AP) is a life-threatening condition, with a higher mortality rate in men than women and in which estrogens might play a protective role. This study aimed to investigate sex-dependent differences in a mouse model of caerulein-induced AP. Thirty-six C57BL/6J mice (19 females and 17 males) were treated intraperitoneally with phosphate-buffered saline or caerulein, and sacrificed 12 hours, 2 days, or 7 days after the last injection. Blood was collected for amylase, lipase, and glucose determination. Severity and extent of inflammation, apoptosis, and acinar to ductal metaplasia (ADM) in pancreatic tissue were scored histologically and total macrophages, major histocompatibility complex (MHC)-II+ cells, M2 macrophages, T and B cells, neutrophils, apoptosis, and ADM were marked immunohistochemically and quantified by digital image analysis. Serum amylase had a peak at 12 hours, without differences between the sexes. In females, pancreatitis reached a peak at 12 hours with a fast recovery while, in males, the peak was delayed to day 2 with residual apoptosis still present. Macrophages were the main inflammatory cell population, followed by T cells, B cells and neutrophils, without differences between sexes. In males, CD206+ cells and apoptosis were higher at both days 2 and 7, and cytokeratin-19+ (CK19+) ADM was higher at day 7 compared with females. The results of this study revealed a faster onset and resolution of caerulein-induced AP in female mice compared with male mice, supporting a sex-dependent modulation of acute pancreatitis.

Programmed cell death-related gene IL20RA facilitates tumor progression and remodels tumor microenvironment in thyroid cancer

Programmed cell death (PCD) is a vital biological process that is essential for regulating cell progression and tumor microenvironment. This study aimed to explore the relationship between PCD-related genes expression and prognosis in thyroid cancer (THCA), especially IL20RA, as a potential prognostic marker for THCA. Data from The Cancer Genome Atlas (TCGA) database was utilized to develop a PCD-related risk prediction model based on LASSO regression along with univariate Cox regression. The correlation between PCD-related genes and immune cell infiltration was also assessed. The prognostic value of the key PCD-related gene for THCA was investigated by immunohistochemistry. The immune regulatory function and biological function of the key PCD related molecules were detected by cellular experiments. We identified four PCD-related genes (NPC2, E2F1, IL20RA, and TREM2) and constructed a risk model that exhibited excellent accuracy in predicting the prognosis of THCA. Moreover, we confirmed that high expression of IL20RA related to the poor prognosis of THCA. IL20RA promoted cell proliferation and IL20RA knockdown increased apoptosis and ferroptosis. Analysis of the immune microenvironment and detection of macrophages polarization showed that IL20RA promoted the polarization of M2 macrophages while reducing the polarization of M1. We constructed a prognostic prediction model and identified several PCD-related genes. The function of IL20RA which could potentially provide a foundation for additional investigations into diagnostic markers and treatment targets for THCA.

Naltriben promotes tumor growth by activating the TRPM7-mediated development of the anti-inflammatory M2 phenotype

Macrophage plasticity is critical for maintaining immune function and developing solid tumors; however, the macrophage polarization mechanism remains incompletely understood. Our findings reveal that Mg2+ entry through distinct plasma membrane channels is critical to macrophage plasticity. Naïve macrophages displayed a previously unidentified Mg2+ dependent current, and TRPM7-like activity, which modulates its survival. Significantly, in M1 macrophages, Mg2+ entry is facilitated by a novel Mg²-dependent current that relies on extracellular Mg2+, which was crucial for activating iNOS/NFκB pathways and cellular bioenergetics, which drives pro-inflammatory cytokines. Conversely, in M2 macrophages, Mg2+ entry occurs primarily through TRPM7 channels, pivotal for IL-4 and IL-10-mediated anti-inflammatory cytokine secretion. Notably, the Mg2+ deficient diet or addition of TRPM7 agonist Naltriben suppresses the M1 phenotype while promoting angiogenic factors and fostering tumor growth. These findings suggest that Mg2+ flux via specific channels is indispensable for macrophage polarization, with its dysregulation playing a pivotal role in tumor progression.

Fabrication of Hypoxia-Mimicking Supramolecular Hydrogels for Cartilage Repair.

Despite advancements in chronic arthritis treatment, there remains a significant demand for advanced nanotechnologies capable of efficiently delivering a wide range of therapeutic agents to provide symptomatic relief and facilitate the healing of inflamed cartilage tissue. Considering the significant impact of hypoxia on the development and maintenance of chondral tissue, replicating its effects on stem cells could be a potential approach for the treatment of osteoarthritis (OA). Cobalt is a prominent hypoxia-inducing agent, owing to its ability to activate the hypoxia-inducible factor (HIF) pathway regardless of cellular oxygen levels. The intra-articular (IA) injection of dexamethasone (Dex) is often used to alleviate inflammation and pain associated with OA. Nevertheless, several obstacles impede the drug's efficacy, including its short duration of action and rapid elimination from the joint space. Considering these research problems, the study brings an advanced strategy for the development of a three-dimensional (3D) bioprintable hypoxia-mimicking supramolecular hydrogel (HMSG) through the self-assembly of Dex-loaded poly(ethylene glycol) diacrylate (PEGDA) guest polymers with acryloyl β-cyclodextrin (AβCD) host monomers, in combination with cobalt nanowires (Co NWs). Through the process of photo-cross-linking, HMSG can generate multivalent host-guest nanoclusters, making it an excellent candidate for 3D bioprinting, showcasing remarkable mechanical properties. By effectively delivering Dex and Co2+ in a sustained manner, the HMSG affords a suitable microenvironment for the encapsulated umbilical cord-derived mesenchymal stem cells (UMSCs), thereby promoting the synthesis of matrix components and decreasing the release of catabolic factors. Moreover, the HMSG ameliorates OA severity by increasing the M2 macrophage polarization, which can ultimately contribute to immunomodulatory effects. In conclusion, the results propose potential approaches for utilizing HMSG as efficient carriers to transport various therapeutic molecules to the injury site, thereby assimilating into nearby tissues and promoting successful tissue repair without the need for external growth factors.

Investigating the role of intratumoral Streptococcus mitis in gastric cancer progression: insights into tumor microenvironment

Growing evidence implicates that intratumoral microbiota are closely linked to cancer progression; however, research on the role of these microbiota in the development of gastric cancer remains limited. Here, using 16 S rRNA sequencing, tumor tissue proteomics and serum cytokines analysis, we identified enrichment of specific microbial communities within tumors of gastric cancer patients, possibly affecting the tumor microenvironment by immune modulation, metabolic processes, and inflammatory responses. Based on the results of in vivo experiments and intratumoral microbiota analysis, we found that Streptococcus mitis can inhibit gastric cancer progression via suppressing M2 macrophage polarization and infiltration, as well as altering the intratumoral microbial community. In summary, our findings suggest that the intratumoral microbiota, exemplified by Streptococcus mites, may be involved in regulating the progression of gastric cancer, thereby emerging as potential therapeutic targets for this disease.

Polyoxometalate-based injectable coacervate inhibits HCC metastasis after incomplete radiofrequency ablation via scavenging ROS

BackgroundIncomplete radiofrequency ablation (iRFA) stimulates residual hepatocellular carcinoma (HCC) metastasis, leading to a poor prognosis for patients. Therefore, it is imperative to develop an effective therapeutic strategy to prevent iRFA-induced HCC metastasis.ResultsOur study revealed that iRFA induced an abnormal increase in ROS levels within residual HCC, which enhanced tumor cell invasiveness and promoted macrophage M2 polarization, ultimately facilitating HCC metastasis. Molybdenum-based polyoxometalate (POM) is an excellent ROS-scavenging nanocluster, but its size is too small to be easily cleared by the kidneys, limiting its effectiveness in scavenging iRFA-induced ROS. To overcome this limitation, we synthesized an injectable POM-loaded coacervate delivery system named POM@Coa, which can sustainably scavenge iRFA-induced ROS by slowly releasing POM. POM@Coa markedly reduced HCC invasiveness, reversed macrophage polarization from M2 to M1, and promoted the infiltration and activation of CD8+ T cells, ultimately inhibiting HCC metastasis. Importantly, POM@Coa showed superior therapeutic efficacy to free POM in the absence of systemic toxicity.ConclusionsPOM@Coa exhibits the potential to decrease HCC invasiveness and activate anti-tumor immunity, opening up new avenues for the safe and effective treatment and prevention of HCC metastasis when combined with RFA.

Ablation of the deubiquitinating enzyme cylindromatosis (CYLD) augments STAT1-mediated M1 macrophage polarization and fosters Staphylococcus aureus control

Ablation of the deubiquitinating enzyme cylindromatosis (CYLD) augments STAT1-mediated M1 macrophage polarization and fosters Staphylococcus aureus control

APD-L1-facilitated theranostic and tumor microenvironment remodeling of pancreatic cancer via docetaxel-loaded phase-transformation nanoparticles triggered by low-intensity pulsed ultrasound

Early diagnosis of pancreatic ductal adenocarcinoma (PDAC) is challenging because of its depth, which often leads to misdiagnosis during ultrasound examinations. The unique PDAC tumor microenvironment (TME) is characterized by significant fibrous tissue growth, and high interstitial pressure hinders drug penetration into tumors. Additionally, hypoxia and immune suppression within the tumor contribute to poor responses to radiotherapy and chemotherapy, ultimately leading to an unfavorable prognosis. In this study, aPD-L1-modified docetaxel and perfluoropentane-loaded liquid‒vapor phase-transformation lipid nanoparticles (aPDL1-DTX/PFP@Lipid) were synthesized and had an average diameter of 61.63 nm with 84.3% antibody modification. We demonstrated that the nanoparticles (NPs) exhibited excellent PDAC-targeting capabilities both in vitro and in vivo. Upon exposure to low-intensity pulsed ultrasound (LIPUS) stimulation, the NPs underwent a phase transformation to form microbubbles with substantial molecular ultrasound diagnostic effects, and combined treatment resulted in a tumor growth inhibition rate of 88.91%. This treatment strategy also led to the infiltration of CD8+ T cells, the downregulation of Treg cells, the promotion of M1 macrophage polarization, the inhibition of fibrosis to reduce tumor stromal pressure, and the facilitation of perfluoropentane (PFP) gasification to release O2 and improve tumor hypoxia. In conclusion, aPD-L1-modified liquid‒vapor phase-transformation nanoparticles loaded with docetaxel (DTX) and PFP were successfully combined with ultrasound for the molecular diagnosis and targeted treatment of PDAC. aPDL1-DTX/PFP@Lipid could reshape the PDAC TME, offering a new approach for ultrasound-mediated diagnosis and treatment with promising clinical applications.Graphical

Understanding the Dual Role of Macrophages in Tumor Growth and Therapy: A Mechanistic Review.

Macrophages are heterogeneous cells that are the mediators of tissue homeostasis. These immune cells originated from monocytes and are classified into two basic categories, M1 and M2 macrophages. M1 macrophages exhibit anti-tumorous inflammatory reactions due to the behavior of phagocytosis. M2 macrophages or tumor-associated macrophages (TAMs) are the most abundant immune cells in the tumor microenvironment (TME) and have a basic role in tumor progression by interacting with other immune cells in TME. By the expression of various cytokines, chemokines, and growth factors, TAMs lead to strengthening tumor cell proliferation, angiogenesis, and suppression of the immune system which further support invasion and metastasis. This review discusses recent and updated mechanisms regarding tumor progression by M2 macrophages. Moreover, the current therapeutic approaches targeting TAMs, their advantages, and limitations are also summarized, and further treatment approaches are outlined along with an elaboration of the tumor regression role of macrophages. This comprehensive review article possibly helps to understand the mechanisms underlying the tumor progression and regression role of macrophages in a comparative way from a basic level to the advanced one.

Identification of ubiquitination-related key biomarkers and immune infiltration in Crohn’s disease by bioinformatics analysis and machine learning

Crohn’s disease (CD) is a chronic inflammatory bowel disease with an unknown etiology. Ubiquitination plays a significant role in the pathogenesis of CD. This study aimed to explore the functional roles of ubiquitination-related genes in CD. Differentially expressed ubiquitination-related genes were identified by intersecting differentially expressed genes (DEGs) from the GSE95095 dataset in the Gene Expression Omnibus (GEO) database with a set of ubiquitination-related genes. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses were performed. Key genes were selected by combining hub genes from the protein-protein interaction (PPI) network with feature genes identified by Lasso and Random Forest (RF) algorithms. Additionally, the correlation between key genes and immune infiltration was assessed, and Gene Set Enrichment Analysis (GSEA) of key genes was conducted. The efficacy of key genes was validated using ROC curves in an external dataset, and their expression was confirmed in LPS-induced Caco-2 cells through RT-qPCR. A total of 32 ubiquitination-related DEGs were identified, and two key genes (UBE2R2, NEDD4L) were selected. The infiltration of M2 macrophages was reduced in CD patients, with UBE2R2 expression negatively correlated and NEDD4L expression positively correlated with M2 macrophage infiltration. GSEA indicated that UBE2R2 was enriched in terpenoid backbone biosynthesis, regulation of autophagy, and limonene and pinene degradation, while NEDD4L was enriched in lysosome, Wnt signaling, and calcium signaling pathways. ROC curves demonstrated superior efficacy for NEDD4L. In LPS-induced Caco-2 cells, UBE2R2 expression increased, while NEDD4L expression decreased. A comprehensive analysis of the functional relationship between ubiquitination-related genes and CD can enhance understanding of CD pathogenesis and suggest potential therapeutic targets.

HMOX1 as a potential drug target for upper and lower airway diseases: insights from multi-omics analysis

Background Oxidative stress is key in inflammatory airway diseases. Heme oxygenase 1 (HMOX1) regulates oxidative stress, but its role in airway diseases needs exploration.MethodsDifferentially expressed genes (DEGs) between healthy nasal mucosa and chronic rhinosinusitis with nasal polyps (CRSwNP) were identified from Gene Expression Omnibus (GEO). Candidate genes were further screened using Gene Set Enrichment Analysis (GSEA) and Random Forest (RF) algorithms. Causal inference between candidate genes and upper and lower airway diseases (CRSwNP, allergic rhinitis (AR), and asthma (AS)) was conducted using bidirectional two-sample Mendelian randomization (TwoSampleMR) analysis. Single-cell RNA sequencing (scRNA-seq) data were used to determine the cellular localization and intercellular interactions of candidate genes. Molecular docking was used to identify potential therapeutic agents.ResultsHMOX1 expression was significantly elevated in CRSwNP. TwoSampleMR analysis indicated a negative causal relationship between HMOX1 exposure and the occurrence of upper and lower airway diseases (CRSwNP [(odds ratio (OR)/95% confidence interval (CI): 0.945/(0.893–0.999), P = 0.044], AR [OR/95% CI: 0.997/(0.994–0.999), P = 0.007], and AS [OR/95% CI: 0.935/(0.895–0.977), P = 0.003]). scRNA-seq data revealed HMOX1 localization in M2 macrophages. Molecular docking identified 15 antioxidants, including Acetylcysteine and Quercetin, that can upregulate HMOX1 expression.ConclusionHMOX1 may have a protective role in the pathogenesis of upper and lower airway diseases (CRSwNP, AR, and AS) by modulating oxidative stress. Antioxidants that increase HMOX1 expression could offer new therapeutic avenues for these diseases.Clinical trialNot applicable.

Boswellia Extract Promotes Healing and Resolving Inflammation in Oral Ulcers of Rat.

Recurrent aphthous ulcers significantly impact patients' quality of life due to their painful and recurrent nature, necessitating more effective treatments. This study explores the therapeutic potential of Boswellia to treat recurrent aphthous ulcers by its anti-inflammatory and healing promotion effect in a rat oral ulcer model. Network pharmacology techniques were employed to elucidate Boswellia's active components and potential targets. Intersecting targets of Boswellia and oral ulcer-related genes were screened for protein-protein interaction network analysis and functional enrichment. An oral ulcer model in rats was used and rats were treated with Boswellia extract. The healing process was monitored by measuring the ulcer area and body weight changes. Histological analysis was performed, and the role of Boswellia in macrophage polarization was investigated through gene expression analysis and protein array tests. The underlying mechanism involving PPARγ activation was also explored. Network pharmacology analysis revealed Boswellia's interaction with key genes and pathways associated with inflammation and lipid metabolism, such as MAPK3, PPARG, and PTGS2. Boswellia extract significantly accelerated oral ulcer healing and recovered weight loss in rats. Histological examinations revealed reduced tissue swelling and inflammatory cell infiltration in treated groups. Furthermore, Boswellia extract decreased infiltration of M1 macrophage presence while increasing M2 macrophage, indicating an inflammation-resolving effect. Invitro studies showed that Boswellia extract enhanced M2-related gene expression and decreased pro-inflammatory cytokines, which is PPARγ dependent. Boswellia extract promotes oral ulcer healing and resolves inflammation, primarily through the modulation of macrophage polarization via PPARγ activation.

Tumor-associated-fibrosis and active collagen-CD44 axis characterize a poor-prognosis subtype of gastric cancer and contribute to tumor immunosuppression

BackgroundTumor-associated fibrosis modifies the tumor microenvironment (TME), hinders the infiltration and activity of cytotoxic immune cells, and is a critical pathological process leading to the ineffectiveness of tumor immunotherapy in gastric cancer (GC). However, the specific mechanisms and interventions are yet to be fully explored.MethodsOur study included 375 gastric cancer samples from TCGA, 1 single-cell RNA sequencing (scRNA-seq) dataset comprising of 15 gastric cancer samples from GEO, 19 cohorts of immunotherapy and 2 GWAS datasets. Consensus clustering identified a gastric cancer subtype characterized primarily by fibrosis, and various methods such as pseudotime analysis, CellChat analysis and Colocalization analysis were used to explore its mechanisms.ResultsA subtype of gastric cancer was identified with poor prognosis, characterized by higher malignancy, drug resistance, and poor immune infiltration, associated with elevated expression of genes related with Extracellular matrix (ECM). Single-cell transcriptome analysis showed active Collagen-CD44 signaling axis between cancer-associated fibroblasts (CAFs) and immune cells in gastric cancer, with ECM-related genes upregulated during tumor progression. The expression of CD44 was significantly elevated in the subtype, associated with poor prognosis and tumor immune suppression in gastric cancer, potentially involved in the recruitment of immunosuppressive cells such as M2 macrophages and regulatory T cells (Tregs) and the upregulation of multiple immune checkpoints including PD-1/PD-L1.ConclusionOur study identified a new subtype of gastric cancer, revealing that fibrosis is a critical mechanism driving immune suppression in gastric cancer and emphasizing the central role of the Collagen-CD44 signaling axis. The Collagen-CD44 signaling axis has the potential to serve as a novel therapeutic target for gastric cancer by enhancing immune cell-mediated tumor suppression. By combining it with immune checkpoint inhibitors (ICIs), it may improve the efficacy of immunotherapy for gastric cancer and offer new hope for treatment.

A detoxified TLR4 agonist inhibits tumour growth and lung metastasis of osteosarcoma by promoting CD8+ cytotoxic lymphocyte infiltration

BackgroundOsteosarcoma is the most common malignant bone tumour with limited treatment options and poor outcomes in advanced metastatic cases. Current immunotherapies show limited efficacy, highlighting the need for novel therapeutic approaches. Systemic immune activation by Toll-like receptor 4 (TLR4) immunostimulants has shown great promise; however, current TLR4 agonists’ toxicity hinders this systemic approach in patients with osteosarcoma.MethodsWe compared the antitumour effect of lipopolysaccharides (LPS) with that of an innovative chemically detoxified TLR4 agonist (Lipo-MP-LPS) in a syngeneic metastatic osteosarcoma mouse model. Lipo-MP-LPS exhibited an optimal safety and solubility profile for systemic administration at an effective dose. We evaluated tumour growth, lung metastases, and immune cell infiltration in wild-type and TLR4-mutant mice and performed selective immunodepletion.ResultsLipo-MP-LPS exhibited antitumour effects against localised osteosarcoma tumours and lung metastases, like those of natural LPS. Lipo-MP-LPS promoted CD8+ T cells and M1 macrophages infiltration in primary tumours and CD8+ T cells in metastases, with an M1-phenotype macrophage shift. The Lipo-MP-LPS antitumour effects were found to depend on TLR4 and CD8+ T cells, but not on macrophages.ConclusionLipo-MP-LPS inhibited tumour growth and lung metastasis of osteosarcoma by promoting CD8 + T cell infiltration, indicating its therapeutic potential for advanced osteosarcoma.

Effectiveness of gua sha with Masanggoubang oil in rats with chronic soft tissue injury.

Chronic soft tissue injury is characterized by sterile inflammation and pain. Gua sha with Masanggoubang oil (GSMO) treatment has been found to possess anti-inflammatory and analgesic effects. To explore the mechanism of GSMO in chronic soft tissue injuries. Fifty male rats were randomly divided into 5 groups (n = 10): 1) control group; 2) chronic soft tissue injury model group; 3) GSMO group; 4) inunction with Masanggoubang oil (IMO) group; and 5) ua sha with tea oil (GSTO) group. The control group and model group received no treatment, while the GSTO group and GSMO group received gua sha therapy with tea oil or Masanggoubang oil on the injured sites. The rats in the IMO group were treated with Masanggoubang oil inunction on the injured sites once every other day, 4 times in total. All animals were sacrificed 48 h after the last treatment. Muscle tissue sections from the injured sites of the rats were stained with hematoxylin & eosin (H&E) staining to observe pathological changes. The protein levels of tumor necrosis factor alpha (TNF-α), interleukin 1β (IL-1β), interleukin 6 (IL-6), inducible nitric oxide synthase (iNOS), and β-endorphin (β-EP) in the rats' skin, serum, and muscle were determined using enzyme-linked immunosorbent assay (ELISA). Gua sha with Masanggoubang oil treatment alleviated necrosis and the denaturation of muscle fibers at the injured sites, reduced connective tissue proliferation and scar tissue generation, downregulated the levels of TNF-α, IL-6 and iNOS in the skin and TNF-α, IL-1β, IL-6, and iNOS in the muscle and serum, and upregulated β-EP levels in the muscle. Gua sha with Masanggoubang oil treatment significantly improved the inflammatory response in rats with chronic soft tissue injury, which may be associated with a reduction of M1 macrophage polarization in the peripheral blood and local tissues. Additionally, the combination of gua sha therapy and Masanggoubang oil may have a synergistic effect in treating chronic soft tissue injuries.

Expression of PCED1A in Hepatocellular Carcinoma and Colorectal Cancer and Its Relationship with Immune Infiltration: Potential as a Diagnostic Marker.

Hepatocellular carcinoma (HCC) and colorectal cancer (CRC) pose a significant threat to human health worldwide, characterized by intricate pathogenesis. A PC-esterase domain containing 1A (PCED1A) is a critical number of the GDSL/SGNH superfamily. The aim of this study is to explore the diagnostic value of PCED1A in HCC and CRC and its relationship with immune infiltration. The Cancer Genome Atlas (TCGA) database, Gene Expression Omnibus (GEO) database, the Cancer Cell Line Encyclopedia database (CCLE), and the Human Protein Atlas (HPA) were used to detect the expression of PCED1A in tissues and cells. Cibersoft, Timer, and Xcell were used to analyze the effect of PCED1A on immune cell infiltration. The relationship between PCED1A and the immune checkpoint was analyzed. The coexpression analysis of PCED1A was conducted using the LinkedOmics database. PCED1A was increased in HCC and CRC with poor prognosis. Immunohistochemistry demonstrated that PCED1A was highly expressed in HCC and CRC compared to corresponding normal tissues. PCED1A expression was related to poor overall survival (OS) and progression-free survival (PFS). High PCED1A expression was strongly associated with M2 macrophages, impacting HCC progression. Conversely, low PCED1A expression was closely related to Th2 cells in CRC. In addition, the checkpoint named PDCD1 showed a good correlation with PCED1A high expression group in HCC and CRC. Lastly, the PCED1A and ZNF family showed a complex and intertwined relationship through coexpression analysis on the LinkedOmics database. PCED1A, related to tumor immune infiltration, is a promising diagnostic biomarker and a valuable therapeutic target for HCC and CRC.

PFKFB3 decreases α-ketoglutarate production while partial PFKFB3 knockdown in macrophages ameliorates arthritis in tumor necrosis factor-transgenic mice.

Aberrant 6-phosphofructo-2kinase/fructose-2,6-bisphoshatase 3 (PFKFB3) expression is tightly correlated with multiple steps of tumorigenesis; however, the pathological significance of PFKFB3 in macrophages in patients with rheumatoid arthritis (RA) remains obscure. In this study, we examined whether PFKFB3 modulates macrophage activation and promotes RA development. Peripheral blood mononuclear cells (PBMCs) from patients with RA, THP-1 cells, and bone marrow-derived macrophages from conditional PFKFB3-knockout mice were used to investigate the mechanism underlying PFKFB3-induced macrophage regulation of RA. We demonstrated that patients with RA have higher PFKFB3 levels than healthy volunteers. PFKFB3 silencing suppressed M1 macrophage polarization and downregulated IL-1β, CD80, IFIT1, CCL8, and CXCL10 in macrophages of patients with RA. PFKFB3 overexpression markedly upregulated IRF5, HIF1α, IL-1β, CD80, IFI27, IFI44, IFIT1, IFIT3, CCL2, CCL8, CXCL10, CXCL11, and MMP13 in phorbol 12-myristate 13-acetate-induced THP-1 cells, although these changes were partially reversed by PFK15, an inhibitor of PFKFB3 enzyme activity. Co-immunoprecipitation assays revealed that PFKFB3 interacted with GLUD1 and decreased glutamate dehydrogenase (GDH) activity and α-ketoglutarate production. PFKFB3, TNFα, IL-6, IFNγ, CXCL9, CXCL10, CXCL11, MMP13, and MMP19 were downregulated in bone marrow-derived macrophages of conditional PFKFB3-knockout mice relative to those of wild-type mice. Partial PFKFB3 knockdown in macrophages ameliorated the clinical signs of arthritis and bone destruction, inhibited proinflammatory factor expression, and promoted GDH activity and α-ketoglutarate production in tumor necrosis factor-transgenic mice. Single-cell sequencing revealed that macrophages were the most abundant cells in the ankles of arthritic mice, and partial PFKFB3 knockdown promoted M2-like polarization and was correlated with TREM2, SPP1, APOE, and C1Q expression. PFKFB3 is upregulated in macrophages in patients with RA. PFKFB3 aggravates arthritis by modulating macrophage activity, which may be related to decreased α-ketoglutarate production.

Inhibition of Kv1.3 channel restrains macrophage M2 polarization and ameliorates renal fibrosis via regulating STAT6 phosphorylation.

Macrophages play crucial roles in regulating both homeostatic and inflammatory responses, with classical activated (M1) and alternatively activated (M2) subsets defined by the surrounding micro-environment. Renal fibrosis, developed from persistent inflammation, is worsened by M2 macrophages, yet the precise mechanisms underlying macrophage M2 polarization remain unclear. In this study, we investigated the role of Kv1.3, one of the primary potassium channels which is expressed in both innate and adaptive immunity, on macrophage M2 polarization and renal fibrosis. Our findings demonstrated that genetic or pharmacological inhibition of Kv1.3 significantly suppressed the expression of M2 markers and STAT6 phosphorylation. Furthermore, pharmacological inhibition of Kv1.3 by PAP-1 attenuated renal inflammation and fibrosis with decreased infiltration of macrophage infiltration and M2 polarization by employing the unilateral ureteral obstruction (UUO) renal fibrosis model. Mechanistically, we revealed that Kv1.3 was required for STAT6 phosphorylation in a mitochondria membrane potential dependent manner. Collectively, this study suggests that Kv1.3 is essential for macrophage M2 polarization and highlights the potential of Kv1.3 blockers as therapeutic agents for renal fibrosis and other M2 polarization-related diseases.

SLAMF8 Disrupts Epithelial Barrier in Chronic Rhinosinusitis with Nasal Polyps via M1 Macrophage Polarization.

Recent studies show that M1 macrophages accumulate predominantly in non-eosinophilic chronic rhinosinusitis with nasal polyps (neCRSwNP). However, the precise mechanisms regulating M1 macrophages and their impact on the epithelial barrier remain unclear. We aim to investigate the expression and regulatory role of SLAMF8, a molecule exclusively expressed in myeloid cells, in M1 macrophage polarization and its potential contribution to neCRSwNP development. We evaluated SLAMF8 expression and its correlation with clinical variables using real-time quantitative polymerase chain reaction and Western blot in sinonasal mucosa samples from CRSwNP and control subjects. Immunofluorescence staining confirmed the co-expression of SLAMF8 with macrophages. After SLAMF8 knockdown, we explored the influence on macrophage M1 polarization and the effect on epithelial-mesenchymal transition (EMT) process and tight junction integrity in epithelial cells through an indirect co-culture system of M1 macrophages with human nasal epithelial cells. SLAMF8 was highly expressed on M1 macrophages in polyp tissues, notably in neCRSwNP, and correlated with disease severity indices only in neCRSwNP. SLAMF8 knockdown in THP-1 cells reduced M1 macrophage markers (CD86, iNOS, and NLRP3) and decreased secretion of inflammatory cytokines (IL-1β, IL-6, and TNF-α). Co-culture with M1 macrophage supernatant after SLAMF8 knockdown enhanced epithelial viability, reduced EMT and apoptosis, and upregulated tight junction markers Occludin and Claudin-4 in nasal epithelial cells. SLAMF8 elevation correlates with the EMT, epithelial tight junction and disease severity in neCRSwNP. The SLAMF8 upregulation promotes M1 macrophage polarization, by which facilitates EMT and impairs nasal epithelial barrier function. SLAMF8 may represent a novel therapeutic target for neCRSwNP.

Polymerized Type I Collagen Downregulates STAT-1 Phosphorylation Through Engagement with LAIR-1 in Circulating Monocytes, Avoiding Long COVID

The intramuscular administration of polymerized type I collagen (PTIC) for adult symptomatic COVID-19 outpatients downregulated hyperinflammation and improved symptoms. We inferred that LAIR1 is a potential receptor for PTIC. Thus, a binding assay and surface plasmon resonance binding assay were performed to estimate the affinity of the interaction between LAIR1 and PTIC. M1 macrophages derived from THP-1 cells were cultured with 2–10% PTIC for 24 h. Lysates from PTIC-treated THP-1 cells, macrophage-like cells (MLCs), M1, M1 + IFN-γ, and M1 + LPS were analyzed by Western blot for NF-κB (p65), p38, STAT1, and pSTAT1 (tyrosine701). Serum cytokine levels and monocyte LAIR1 expressions (Mo1 and Mo2) were analyzed by luminometry and flow cytometry in symptomatic COVID-19 outpatients on PTIC treatment. PTIC-bound LAIR1 had a similar affinity to collagen in M1 macrophages. It downregulated pSTAT1 in IFN-γ-induced M1. COVID-19 patients under PTIC treatment showed a significant decrease in Mo1 percentages and cytokines (IP-10/MIF/eotaxin/IL-8/IL-1RA/M-CSF) associated with STAT1 and an increase in the Mo2 subset. The inflammatory mediators and Mo1 downregulation were related to better oxygen saturation and decreased dyspnea, chest pain, cough, and chronic fatigue syndrome in the acute and long-term phase of infection. PTIC is an agonist of LAIR1 and downregulates STAT-1 phosphorylation. PTIC could be relevant for treating STAT1-mediated inflammatory diseases, including COVID-19 and long COVID.