M2 Phenotype Research Articles

Ultrasound-responsive nanocarriers with siRNA and Fe3O4 regulate macrophage polarization and phagocytosis for augmented non-small cell lung cancer immunotherapy

The immunosuppressive tumor microenvironment (TME) significantly inhibits the effective anti-tumor immune response, greatly affecting the efficacy of immunotherapy. Most tumor-associated macrophages (TAMs) belong to the M2 phenotype, which contributes significantly to the immunosuppressive effects in non-small cell lung cancer (NSCLC) TME. The interaction between signal regulatory protein α (SIRPα) expressed on macrophages and CD47, a transmembrane protein overexpressed on cancer cells, activates the "eat-me-not" signaling pathway, inhibiting phagocytosis. In this study, a folic acid (FA)-modified ultrasound responsive gene/drugs delivery system, named FA@ PFP @ Fe3O4 @LNB-SIRPα siRNA (FA-PFNB-SIRPα siRNA), was developed using 1,2-dioleoacyl-3-trimethylammonium-propane (DOTAP), FA-1,2-distearoyl-sn-glycero-3-phosphoethanolamine-N- [amino (polyethylene glycol)2000] (DSPE-PEG2000-FA), cholesterol, and perfluoropentane (PFP), for the delivery of siRNA encoding SIRPα mRNA and immune adjuvant Fe3O4 nanoparticles. Under ultrasound conditions, the nanobubbles effectively transfected macrophages, inhibiting SIRPα mRNA and protein expression, promoting the phagocytosis of TAMs, and synergistically reversing M2 polarization. This system promotes the infiltration of T cells, enhances the proliferation and activation of cytotoxic T cells, and inhibits the infiltration of immunosuppressive cells in tumor tissues. Administration of FA-PFNB-SIRPα siRNA combined with ultrasound significantly inhibits NSCLC progression. The study highlights the potential of ultrasound nanotechnology-enabled delivery of SIRPα siRNA and Fe3O4 as an effective strategy for macrophage-based immunotherapy to reshape the immunosuppressive TME for cancer therapy.Graphical

Engineered microparticles modulate arginine metabolism to repolarize tumor-associated macrophages for refractory colorectal cancer treatment

BackgroundArginase is abundantly expressed in colorectal cancer and disrupts arginine metabolism, promoting the formation of an immunosuppressive tumor microenvironment. This significant factor contributes to the insensitivity of colorectal cancer to immunotherapy. Tumor-associated macrophages (TAMs) are major immune cells in this environment, and aberrant arginine metabolism in tumor tissues induces TAM polarization toward M2-like macrophages. The natural compound piceatannol 3ʹ-O-glucoside inhibits arginase activity and activates nitric oxide synthase, thereby reducing M2-like macrophages while promoting M1-like macrophage polarization.MethodsThe natural compounds piceatannol 3ʹ-O-glucoside and indocyanine green were encapsulated within microparticles derived from tumor cells, termed PG/ICG@MPs. The enhanced cancer therapeutic effect of PG/ICG@MP was assessed both in vitro and in vivo.ResultsPG/ICG@MP precisely targets the tumor site, with piceatannol 3ʹ-O-glucoside concurrently inhibiting arginase activity and activating nitric oxide synthase. This process promotes increased endogenous nitric oxide production through arginine metabolism. The combined actions of nitric oxide and piceatannol 3ʹ-O-glucoside facilitate the repolarization of tumor-associated macrophages toward the M1 phenotype. Furthermore, the increase in endogenous nitric oxide levels, in conjunction with the photodynamic effect induced by indocyanine green, increases the quantity of reactive oxygen species. This dual effect not only enhances tumor immunity but also exerts remarkable inhibitory effects on tumors.ConclusionOur research results demonstrate the excellent tumor-targeting effect of PG/ICG@MPs. By modulating arginine metabolism to improve the tumor immune microenvironment, we provide an effective approach with clinical translational significance for combined cancer therapy.

The Thyroid Hormone Analog GC-1 Mitigates Acute Lung Injury by Inhibiting M1 Macrophage Polarization.

Acute lung injury (ALI)/acute respiratory distress syndrome (ARDS) is a life-threatening condition with a high mortality rate of ≈40%. Thyroid hormones (THs) play crucial roles in maintaining homeostasis of the cellular microenvironment under stress. The previous studies confirmed that the clinical-stage TH analog GC-1 significantly alleviates pulmonary fibrosis by improving the function of mitochondria in epithelial cells. However, the effects of GC-1 on macrophages in lung injury and the related mechanisms remain unclear. This study evaluated the therapeutic effects of GC-1 in two murine models of lipopolysaccharide (LPS)- or hydrochloric acid (HCl)-induced ALI. Additionally, mouse alveolar macrophages (AMs) and human THP-1-derived macrophages are utilized to investigate the impact of GC-1 on macrophage polarization. GC-1 effectively reduces the inflammatory response and lung injury in ALI mice, as evidenced by neutrophil infiltration, cytokine levels, alveolar fluid clearance, and pulmonary pathology. Notably, GC-1 selectively inhibits M1 macrophage polarization, which may be achieved by impeding NF-κB signaling activation through the DNMT3b-PPARγ-NF-κB pathway in a TH receptor β1 (TRβ1)-dependent manner, consequently suppressing the polarization of macrophages toward the M1 phenotype and overproduction of inflammatory cytokines. Overall, these findings highlight the immunomodulatory property of GC-1 as an anti-inflammatory strategy for ALI/ARDS and inflammation-related diseases.

Intranasal Delivery of Pure Nanodrug Loaded Liposomes for Alzheimer's Disease Treatment by Efficiently Regulating Microglial Polarization.

The activated M1-like microglia induced neuroinflammation is the critical pathogenic event in Alzheimer's disease (AD). Microglial polarization from pro-inflammatory M1 toward anti-inflammatory M2 phenotype is a promising strategy. To efficiently accomplish this, amyloid-β (Aβ) aggregates as the culprit of M1 microglia activation should be uprooted. Interestingly, this study finds out that the self-reassembly of curcumin molecules into carrier-free curcumin nanoparticles (CNPs) exhibits multivalent binding with Aβ to achieve higher inhibitory effect on Aβ aggregation, compared to free curcumin with monovalent effect. Based on this, the CNPs loaded cardiolipin liposomes are developed for efficient microglial polarization. After intranasal administration, the liposomes decompose to release CNPs and cardiolipin in response to AD oxidative microenvironment. The CNPs inhibit Aβ aggregation and promote Aβ phagocytosis/clearance in microglia, removing roadblock to microglial polarization. Subsequently, CNPs are endocytosed by microglia and inhibit TLR4/NF-κB pathway for microglia polarization (M1→M2). Meanwhile, cardiolipin is identified as signaling molecule to normalize microglial dysfunction to prevent pro-inflammatory factors release. In AD transgenic mice, neuroinflammation, Aβ burden, and memory deficits are relieved after treatment. Through combined attack by extracellularly eradicating roadblock of Aβ aggregation and intracellularly inhibiting inflammation-related pathways, this nanotechnology assisted delivery system polarizes microglia efficiently, providing a reliable strategy in AD treatment.

Intelligent Hydrogel with Physiologically Dependent Capacities of Photothermal Conversion and Nanocatalytic Medicine to Integratively Inhibit Bacteria and Inflammation for On-Demand Treatment of Infected Wound.

Although chemodynamic therapy (CDT) and photothermal therapy (PTT) based on a variety of nanoparticles have been developed to achieve effective anti-bacterial therapy, the limited therapeutic efficiency of CDT alone, as well as the undifferentiated damage of PTT to both bacteria and surrounding healthy tissue are still challenges for their clinical application of infected wounds treatments. In addition, during the CDT and PTT-mediated antimicrobial processes, the endogenous macrophages would be easily converted to pro-inflammatory macrophages (M1 phenotype) under local ROS and hyperthermia to promote inflammation, resulting in unexpected suppression of tissue regeneration and possible wound deterioration. To address these problems, a biodegradable sodium alginate/hyaluronic acid hydrogel loaded with functional CeO2-Au nano-alloy (AO@ACP) is fabricated to not only achieve precise and efficient antibacterial activity through infection-environment dependent photothermal-chemodynamic therapy but also rapidly eliminate the excess reactive oxygens (ROS) in the M1 type macrophage at the infected area to induce their polarization to M2 type for significant inhibition of inflammation and remarkable enhancement of tissue regeneration, hopefully developing an effective strategy to treat infected wound.

12407 Assessing Human Monocyte Migration And Co-culture With Adrenocortical Cancer Cells

Abstract Disclosure: C. Hong: None. S. Feely: None. R. Challapalli: None. N. Mullen: None. A. Sorushanova: None. C. Hantel: None. M.D. Griffin: None. M.C. Dennedy: None. Adrenocortical carcinoma (ACC) is a lipid, typically steroidogenic cancer which carries a 5-year prognosis of <10%. Therapeutic options are limited including surgery and mitotane – a poorly tolerated and efficacious insecticide. Recent data have demonstrated that the immune environment of adrenocortical carcinoma is deficient in lymphocytes while demonstrating a relative rich monocyte/macrophage population in the tumour microenvironment. We have investigated the gradient for migration of circulating peripheral monocytes to ACC. ACC cells were seeded in the bottom chamber of the transwell system. Monocytes were isolated from human peripheral blood, by negative selection using magnetic beads with high purity (>95%) and quality. Migration of monocytes at 24/48h was evaluated by identifying those remaining in the top chamber, the floating fraction in the bottom chamber and those adherent to ACC cells in the bottom chamber. Analysis of monocyte/macrophages was undertaken by flow cytometry using the following markers: Sytox Blue, CD45, CD14, CD16 and HLA-DR. At 24h, when compared to control conditions, more monocytes had migrated to the ACC cells seeded lower chamber and attached to the bottom. Similar results were observed in migration at 48h. Predominantly Classical monocytes (CD14++CD16-HLA-DR+) migrated to metastatic cancer cells (MUC1), and Non-Classical monocytes (CD14+CD16+HLA-DR+) migrated to primary cancer cells (H295R/ HAC15) at 48h. We then investigated the polarization cytokine profile of migrated monocytes with or without ACC cells at 72 h by multiplex bead-based assay. Migrated monocytes indicated a significant shift toward the M2 phenotype in the presence of H295R or HAC15. The production of the pro-inflammatory factors of IL-6, TNF-alpha, etc. decreased and immunosuppressive factors of IL-10, TARC, etc. increased. MUC1 didn’t increase M2 or M1 cytokine secretion. Moreover, surface markers of migrated monocytes were evaluated at 72h by flow cytometry. When compared to the control group, all 3 ACC cell lines switched monocytes/ macrophages into M2 phenotype, as evidenced by the decrease in the expression of the M1 marker CD86 and the increase in the expression of the M2 markers CD163 and CD206. We demonstrate monocytes migrate and associate with ACC cells: (i) subpopulations differ in transmigration properties in response to ACC cells (ii) monocytes/macrophages exhibit M2 polarization phenotype. Presentation: 6/2/2024

Revolutionizing pressure ulcer regeneration: Unleashing the potential of extracellular matrix-derived temperature-sensitive injectable antioxidant hydrogel for superior stem cell therapy

Pressure ulcers are a common issue in elderly and medically compromised individuals, posing significant challenges in healthcare. Human umbilical cord mesenchymal stem cells (HUMSCs) offer therapeutic benefits like inflammation modulation and tissue regeneration, yet challenges in cell survival, retention, and implantation rates limit their clinical application. Hydrogels in three-dimensional (3D) stem cell culture mimic the microenvironment, improving cell survival and therapeutic efficacy. A thermosensitive injectable hydrogel (adEHG) combining gallic acid-modified hydroxybutyl chitosan (HBC-GA) with soluble extracellular matrix (adECM) has been developed to address these challenges. The hybrid hydrogel, with favorable physical and chemical properties, shields stem cells from oxidative stress and boosts their therapeutic potential by clearing ROS. The adEHG hydrogel promotes angiogenesis, cell proliferation, and collagen deposition, further enhancing inflammation modulation and wound healing through the sustained release of therapeutic factors and cells. Additionally, the adEHG@HUMSC composite induces macrophage polarization towards an M2 phenotype, which is crucial for wound inflammation inhibition and successful healing. Our research significantly propels the field of stem cell-based therapies for pressure ulcer treatment and underscores the potential of the adEHG hydrogel as a valuable tool in advancing regenerative medicine.

Polymeric nanocarrier via metabolism regulation mediates immunogenic cell death with spatiotemporal orchestration for cancer immunotherapy

The limited efficacy of cancer immunotherapy occurs due to the lack of spatiotemporal orchestration of adaptive immune response stimulation and immunosuppressive tumor microenvironment modulation. Herein, we report a nanoplatform fabricated using a pH-sensitive triblock copolymer synthesized by reversible addition-fragmentation chain transfer polymerization enabling in situ tumor vaccination and tumor-associated macrophages (TAMs) polarization. The nanocarrier itself can induce melanoma immunogenic cell death (ICD) via tertiary amines and thioethers concentrating on mitochondria to regulate metabolism in triggering endoplasmic reticulum stress and upregulating gasdermin D for pyroptosis as well as some features of ferroptosis and apoptosis. After the addition of ligand cyclic arginine-glycine-aspartic acid (cRGD) and mannose, the mixed nanocarrier with immune adjuvant resiquimod encapsulation can target B16F10 cells for in situ tumor vaccination and TAMs for M1 phenotype polarization. In vivo studies indicate that the mixed targeting nanoplatform elicits tumor ICD, dendritic cell maturation, TAM polarization, and cytotoxic T lymphocyte infiltration and inhibits melanoma volume growth. In combination with immune checkpoint blockade, the survival time of mice is markedly prolonged. This study provides a strategy for utilizing immunoactive materials in the innate and adaptive immune responses to augment cancer therapy.

Impact of the tumor microenvironment of breast cancer on prognosis and treatment

According to world Health Organization, breast cancer (BC) ranks first among cancer diseases in women in many developed countries of the world and in the Russian Federation. Over the past 20 years, the incidence of breast cancer in the world has increased and continues to increase. This phenomenon dictates the need for a more in-depth molecular biological, genetic and immunological study of the mechanisms of development and progression of this heterogeneous malignant tumor.Recently, there has been increasing interest in the world not on lyin the direct causes of tumor development, but also in factors contributing to its progression, such as the cellular microenvironment of the tumor, the composition of which has a great influence on cancer development, treatment and prognosis. In the cellular microenvironment of the tumor, mononuclear cells are assessed, the proportion of which determines the severity and direction of the immuneresponse. Their importance for choosing the priority type of drug therapy and assessing its effectiveness is shown. The article provide scurrent data on subpopulations of T cells (CD8+, CD4+), B cells (CD20+), and natural killer. Their role in the development and progression of breast cancer is discussed depending on their phenotype. Modern research pays attention to a minor subpopulation of T lymphocytes – TCR-Vδ1+ cells. This subpopulation is represented predominantly in tumor tissue and has an immunosuppressive effect on T-effectors. At the present stage, inflammatory cells – macrophages and neutrophils – are of no less interest. Their role in tumor progression is widely debated. It is known that the differentiation of macrophages into M1 or M2 phenotypes is determined by the tumor microenvironment. The predominance of macrophages with protumor activity promotes tumor progression and cancer metastasis. Additionally, macrophages can stimulate the migration of neutrophils, which, in turn, support the metastasis of breast cancer through the production of matrix metalloproteinases. Matrix metalloproteinase 9 has been reported to promote the formation of vascular endothelial growth factor, which explains the protumor properties of neutrophils. In the context of growing tumor immunotherapy, assessment of tumor microenvironmental factors is promising both in relation to monitoring the effectiveness of breast cancer therapy and in relation to the search for potential therapeutic targets. The review systematizes and summarizes information on this issue to date.

Mechanical Force on Hydrogel Implication on Enhanced Drug Release, Antibacterial, and M2 Macrophage Polarization: New Insights Alleviate Diabetic Wound Healing.

Diabetic foot ulcers/chronic wounds are difficult to treat because of dysfunctional macrophage response and decreased phenotype transition from the M1 to M2 status. This causes severe inflammation, less angiogenesis, microbial infections, and small deformation in wound beds, affecting the healing process. The commercial wound dressing material has limited efficacy, poor mechanical strength, extra pain, and new granulated tissue formed in a mesh of gauze. It is desired to create tough, skin-adhesive, antifouling, sustainable M2 phenotype-enabling, and mechanoresponsive drug-releasing hydrogel. To resolve this, zwitterionic poly(sulfobetaine methacrylate) (SB) incorporated with keratin-exfoliated MoS2 and bee-wax nanoparticles were developed to deliver phenytoin upon application of mechanical forces. Human hair keratin was used for exfoliation of MoS2, and bee-wax nanoparticles loaded with phenytoin were used as cross-linkers of SB hydrogel. The cross-linked SB-MO15-B hydrogel has high mechanical properties, with more tensile strength and strain of 118 kPa and 1485%. Under external mechanical force, hydrogel deformed to release phenytoin of 38% (tensile) and 24% (compressive), which was higher compared to static condition (12%). The penetration of phenytoin into skin tissue was also improved by the mechanical force applied to the hydrogel. SB-MO15-B hydrogel effectively activates the polarization of macrophages toward the M2 phenotype, promotes cell proliferation, and also shows superior antibacterial properties. In vivo results demonstrate that hydrogel rapidly promotes diabetic wound repair through fast antiinflammation and M2 macrophage polarization. Therefore, a robust mechanoresponsive hydrogel would provide a new strategy to deliver the drug and also tune the M2 macrophage polarization for chronic wound healing.

Sporidiobolus pararoseus polysaccharides relieve rheumatoid arthritis by regulating arachidonic acid metabolism and bone remodeling signaling pathway

Rheumatoid arthritis (RA) is an autoimmune-mediated disease with the highest disability rate. Sporidiobolus pararoseus polysaccharides (SPP) have been demonstrated to have anti-rheumatoid and microbiota-modulatory effects; however, the underlying mechanisms remain unclear. This study employed collagen-induced arthritis (CIA) mice to explore the metabolic and genetic pathways. The results revealed SPP intervention significantly reduced the serum levels of rheumatoid and pro-inflammatory complement factors. SPP promoted the transition of macrophages of CIA mice toward the M2 phenotype (F4/80+/CD206+) from an inflammatory phenotype (F4/80+/CD86+) using flow cytometry analysis. A total of 44 metabolites were upregulated, and 110 metabolites were significantly downregulated by SPP compared to those in RA group. The decreased metabolites, 12(S)-HPETE, prostaglandin H2, 15-HETE, hepoxilin B3, and 15-keto-prostaglandin F2a, were mostly enriched in arachidonic acid metabolism (enrichment = 11.4 %), which was highly correlated with the anti-rheumatic activity of SPP. Gene expression analysis revealed that SPP significantly regulated OPG/RANKL/TRAF6 signaling pathway, stimulating osteogenic remodeling. Furthermore, arachidonic acid metabolism was identified as the critical metabolic driver of RA phenotypes and osteoclast differentiation, potentially associated with SPP-reshaped intestinal microbiota (i.e., Rikenellaceae_RC9_gut_group, Bacteroides, and Parabacteroides). Collectively, this study utilized an integrated approach of metabolomics and gene expression analysis to investigate the regulatory role of SPP in RA progression.

Preconditioning of Mesenchymal Stem Cells Enhances the Neuroprotective Effects of Their Conditioned Medium in an Alzheimer's Disease In Vitro Model.

Alzheimer's disease (AD) develops as a result of oxidative damage to neurons and chronic inflammation of microglia. These processes can be influenced by the use of a conditioned medium (CM) derived from mesenchymal stem cells (MSCs). The CM contains a wide range of factors that have neurotrophic, antioxidant, and anti-inflammatory effects. In addition, the therapeutic potential of the CM can be further enhanced by pretreating the MSCs to increase their paracrine activity. The current study aimed to investigate the neuroprotective effects of CM derived from MSCs, which were either activated by a TLR3 ligand or exposed to CoCl2, a hypoxia mimetic (pCM or hCM, respectively), in an in vitro model of AD. We have developed a novel in vitro model of AD that allows us to investigate the neuroprotective and anti-inflammatory effects of MSCs on induced neurodegeneration in the PC12 cell line and the activation of microglia using THP-1 cells. This study demonstrates for the first time that pCM and hCM exhibit more pronounced immunosuppressive effects on proinflammatory M1 macrophages compared to CM derived from untreated MSCs (cCM). This may help prevent the development of neuroinflammation by balancing the M1 and M2 microglial phenotypes via the decreased secretion of proinflammatory cytokines (IL-1β, IL-6, and TNF-α) and increased secretion of IL-4, as well as the expression of IL-10 and TGF-β by macrophages. Moreover, a previously unknown increase in the neurotrophic properties of hCM was discovered, which led to an increase in the viability of neuron-like PC12 cells under H2O2-induced oxidative-stress conditions. These results are likely associated with an increase in the production of growth factors, including vascular endothelial growth factor (VEGF). In addition, the neuroprotective effects of CM from preconditioned MSCs are also mediated by the activation of the Nrf2/ARE pathway in PC12 cells. TLR3 activation in MSCs leads to more potent immunosuppressive effects of the CM against pro-inflammatory M1 macrophages, while the use of hCM led to increased neurotrophic effects after H2O2-induced damage to neuronal cells. These results are of interest for the potential treatment of AD with CM from preactivated MSCs.

Macrophage corpses for immunoregulation and targeted drug delivery in treatment of collagen-induced arthritis mice

The role of pro-inflammatory macrophages (M1) in rheumatoid arthritis (RA) is significant, as they produce excessive cytokines. Targeting efferocytosis is a potential manner to repolarize M1 macrophages into pro-resolving M2 phenotype, which restores immune homeostasis by releasing anti-inflammatory mediators. In this study, liquid nitrogen-treated dead macrophages (DM) are employed to act as a dead cell-derived active targeted drug carrier for shikonin (SHK) and induce efferocytosis in M1 macrophages with the enhancement of SHK as an AMP-activated protein kinase (AMPK)-activator. The synergistic activation of AMPK leads to uncoupled protein 2 (UCP2) upregulation and reprograms M1 macrophages into M2 phenotypes by promoting oxidative phosphorylation. In the mouse model of collagen-induced arthritis, the intravenous administration of DM/SHK leads to a consistent transformation of M1 macrophages into the M2 phenotype within the infiltrative synovium. This transformation of macrophages results in the restoration of immune homeostasis in the synovium through an increase in the production of pro-resolving mediators. Additionally, it inhibits synovial proliferation and infiltration and provides protection against erosion of cartilage and bone. In summary, LNT-based DM serves as an active targeting drug carrier to M1 macrophages and also acts synergistically with SHK to target immunometabolism.

GSP1-111 Modulates the Microglial M1/M2 Phenotype by Inhibition of Toll-like Receptor 2: A Potential Therapeutic Strategy for Depression.

Neuroinflammation plays a vital role in neurodegenerative diseases and neuropsychiatric disorders, and microglia and astrocytes chiefly modulate inflammatory responses in the central nervous system (CNS). Toll-like receptors (TLRs), which are expressed in neurons, astrocytes, and microglia in the CNS, are critical for innate immune responses; microglial TLRs can regulate the activity of these cells, inducing protective or harmful effects on the surrounding cells, including neurons. Therefore, regulating TLRs in microglia may be a potential therapeutic strategy for neurological disorders. We examined the protective effects of GSP1-111, a novel synthetic peptide for inhibiting TLR signaling, on neuroinflammation and depression-like behavior. GSP1-111 decreased TLR2 expression and remarkably reduced the mRNA expression of inflammatory M1-phenotype markers, including tumor necrosis factor (TNF)α, interleukin (IL)-1β, and IL-6, while elevating that of the M2 phenotype markers, Arg-1 and IL-10. In vivo, GSP1-111 administration significantly decreased the depression-like behavior induced by lipopolysaccharide (LPS) in a forced swim test and significantly reduced the brain levels of M1-specific inflammatory cytokines (TNFα, IL-1β, and IL-6). GSP1-111 prevented the LPS-induced microglial activation and TLR2 expression in the brain. Accordingly, GSP1-111 prevented inflammatory responses and induced microglial switching of the inflammatory M1 phenotype to the protective M2 phenotype. Thus, GSP1-111 could prevent depression-like behavior by inhibiting TLR2. Taken together, our results suggest that the TLR2 pathway is a promising therapeutic target for depression, and GSP1-111 could be a novel therapeutic candidate for various neurological disorders.

The involvement of endogenous melatonin in LPS-induced M1-like macrophages and its underlying synthesis mechanism regulated by IRF3

Melatonin (MLT) has been shown to induce polarization of macrophages towards M2-like phenotype and inhibit polarization of macrophages towards M1-like phenotype through exogenous administration, which affects the development of many macrophage polarization-related diseases, such as infectious diseases, cardiovascular diseases, bone diseases, and tumors. However, whether endogenous melatonin has similar influences on macrophage polarization as exogenous melatonin is still under investigation. This study revealed that the process of lipopolysaccharide (LPS) inducing macrophages to polarize towards M1-like phenotype was accompanied by an increase in endogenous MLT secretion. To explore the role of increased endogenous MLT in the polarization process of macrophages, whether similar to the function of exogenous MLT in inhibiting polarization of macrophages towards M1-like phenotype, we established LPS-induced MLT deficiency models in vitro to investigate the effects of endogenous MLT on the secretion of cytokines, co-stimulatory molecules, ROS, and phagocytic function in LPS-induced M1-like macrophages. Additionally, we aimed to elucidate the mechanism by which LPS affects the secretion of endogenous MLT by macrophages. Our results confirm that LPS induces transcription of Aanat through the TLR4/TRIF pathway, consequently facilitating the secretion of MLT by macrophages. In this way, IRF3 is the main transcription factor that regulates Aanat transcription. Endogenous MLT plays a role in inhibiting the polarization of macrophages towards M1 phenotype and delaying cell apoptosis during LPS-induced polarization towards M1 phenotype. This phenomenon may be a form of self-protection that occurs when macrophages engulf pathogens while avoiding oxidative stress and apoptosis caused by LPS. This conclusion clarifies the role of endogenous MLT in the clearance of pathogens by macrophages, providing a theoretical basis for understanding its role in innate immunity.

Modeling tumor-immune interactions using hybrid spheroids and microfluidic platforms for studying tumor-associated macrophage polarization in melanoma

Tumor-associated macrophages (TAMs), as key components of tumor microenvironment (TME), exhibit phenotypic plasticity in response to environmental cues, causing polarization into either pro-inflammatory M1 phenotypes or immunosuppressive M2 phenotypes. Although TAM has been widely studied for its crucial involvement in the initiation, progression, metastasis, and immune regulation of cancer cells, there have been limited attempts to understand how the metastatic potentials of cancer cells influence TAM polarization within TME. Here, we developed a miniaturized TME model using a 3D hybrid system composed of murine melanoma cells and macrophages, aiming to investigate interactions between cancer cells exhibiting various metastatic potentials and macrophages within TME. The increase in spheroid size within this model was associated with a reduction in cancer cell viability. Examining macrophage surface marker expression and cytokine secretion indicated the development of diverse TMEs influenced by both spheroid size and the metastatic potential of cancer cells. Furthermore, a high-throughput microfluidic platform equipped with trapping systems and hybrid spheroids was employed to simulate the tumor-immune system of complex TMEs and for comparative analysis with traditional 3D culture models. This study provides insight into TAM polarization in melanoma with different heterogeneities by modeling cancer-immune systems, which can be potentially employed for immune-oncology research, drug screening, and personalized therapy. Statement of significanceThis study presents the development of a 3D hybrid spheroid system designed to model tumor-immune interactions, providing a detailed analysis of how melanoma cell metastatic potential influences tumor-associated macrophage (TAM) polarization. By utilizing a microfluidic platform, we are able to replicate and investigate the complex tumor-immune system of the tumor microenvironments (TMEs) under continuous flow conditions. Our model holds significant potential for high-throughput drug screening and personalized medicine applications, offering a versatile tool for advancing cancer research and treatment strategies.

Nanozyme-enhanced injectable hyaluronic acid-based hydrogel for the treatment of osteoarthritis

The progression of osteoarthritis (OA) is dramatically accelerated by excessive reactive oxygen species (ROS)-induced apoptosis of chondrocytes and the inflammatory response of synovial macrophages. In this study, we developed an injectable hydrogel with a catalase-mimicking nanozyme activity as a therapeutic agent for OA. In vitro experiments confirmed that the HA and peroxide-mimetic nanoenzyme-enhanced hydrogel, containing ε-polylysine/Mn1.8Co1.2O4 (ε-PLE/MnCoO) nanoparticles, continuously eliminated ROS and inflammatory cytokines while promoting the polarization of inflammatory macrophages (M1 phenotype) towards anti-inflammatory macrophages (M2 phenotype) in dysfunctional microenvironments. When used for intraarticular injections in OA models, the nanoenzyme-enhanced hydrogel effectively reduced oxidative stress by scavenging ROS and regulating the immune microenvironment. It resulted in a subsequent reduction in the expression of inflammatory factors, including MMP-13, TNF-α, IL-1β, and iNOS in both the synovium and joint fluid. Moreover, cartilage repair was enhanced by the promotion of COL-2 and SOX-9 expression in the cartilage tissue, whereas osteophyte formation in OA was reduced. This study introduced an innovative treatment strategy for the clinical management of OA, demonstrating its significant potential for application in treating OA.

Curcumin Alleviates Airway Inflammation in Cough-Variant Asthmatic Rats by Modulating M1/M2 Macrophage Polarization.

With the increase of environmental pollution and atypical pathogen infections, the incidence of cough variant asthma (CVA) has been increasing annually, making it a pressing issue of the medical community. This study aims to observe the ameliorative effect of curcumin on a rat model of cough variant asthma. A rat model of cough variant asthma was induced by sensitization with ovalbumin combined with aluminum hydroxide (Al(OH)3), followed by repeated excitations. The drug was administered on the day of the initial nebulized attack, and gavage was administered for 14 d. Pathological changes in the lung tissues were observed, along with the assessment of cough susceptibility and airway resistance. The number of inflammatory cell eosinophils and leukocytes were determined in alveolar lavage fluid. Additionally, serum inflammatory factors and lung tissues Matrix Metalloproteinase-9 (MMP-9) protein were assessed. The level of M1/M2 macrophages was also detected. Following the administration of curcumin, there was reduced inflammatory infiltration, less disordered arrangement of the lung tissue, and decreased abnormal proliferation of lung tissues in cough variant asthma rats compared to the model group. Curcumin treatment led toa notable reduction in cough frequency, a significant decrease in pro-inflammatory factor concentration levels in serum and inflammatory cell counts in the alveolar lavage fluid, and a marked increase in anti-inflammatory factor levels (p < 0.05). Additionally, curcumin administration led to a significant increase in M2-type macrophage levels, while simultaneously decreasing the levels of M1-type macrophages (p < 0.05). The administration of curcumin effectively ameliorates ovalbumin-induced airway inflammation in cough-variant asthma rats. This effect is attributed to modulating macrophage polarization towards the anti-inflammatory M2 phenotype, thereby reducing airway inflammation, airway hyperresponsiveness, and lung tissue injury.

Promotion of mandibular distraction osteogenesis by parathyroid hormone via macrophage polarization induced through iNOS downregulation

ObjectiveTo investigate whether Parathyroid hormone (PTH) can promote mandibular distraction osteogenesis by regulating macrophage polarization and the underlying mechanisms of this phenomenon. MethodsForty-eight Rabbits were used to establish the mandibular distraction osteogenesis experimental model, randomly divided into 2 groups. Intermittent post-operative injections of 20 μg/kg PTH and normal saline were administered to the experimental and control groups, respectively. Regenerated new bone was examined using HE staining, osteoclast numbers were determined through tartrate-resistant acid phosphatase (TRAP) staining, and macrophage polarization markers arginase 1 (Arg1) and inducible nitric oxide synthase (iNOS) expressions were elucidated using immunohistochemistry (IHC), the mRNA expression of CD206, CD11C, Arg1 and iNOS were detected using qPCR. ResultsThe bone trabeculae in the experimental group were thicker, with a more homogeneous structure and more new osteoid than in the control group. In the area of distraction osteogenesis, the osteoclast count in the experimental group was higher than in the control group (P < 0.05). IHC results indicated differential expressions of Arg1 and iNOS in the experimental group compared to the control group (P < 0.05). Relative mRNA expressions of CD11c and iNOS were lower in the experimental group than in the control group (P < 0.05), whereas the expressions of CD206 and Arg1 mRNA were higher in the experimental group compared to the control group (P < 0.05). ConclusionIntermittent PTH injections increased macrophage quantity in the mandible generated by distraction osteogenesis, downregulated iNOS, upregulated Arg1, and promoted macrophage polarization from M1 to M2 phenotype, thereby promoting mandibular distraction osteogenesis.

Europium-Containing Nanospheres for Treating Ovariectomy-Induced Osteoporosis: Targeted Bone Remodeling and Macrophage Polarization Modulation.

Osteoporosis, characterized by reduced bone mass and structural deterioration, poses a significant healthcare challenge. Traditional treatments, while effective in reducing fracture risks, are often limited by side effects. This study introduces a novel nanocomplex, europium (Eu) ions-doped superparamagnetic iron oxide (SPIO) nanocrystals encapsulated in poly(lactic-co-glycolic acid) (PLGA) nanospheres, abbreviated as SPIO:Eu@PLGA nanospheres, as a potential therapeutic agent for osteoporosis by modulating macrophage polarization, enhancing osteoblast differentiation and inhibiting osteoclastogenesis. SPIO and SPIO:Eu nanocrystals were synthesized through pyrolysis and encapsulated in PLGA using an emulsification method. To evaluate the impact of SPIO:Eu@PLGA nanospheres on macrophage reprogramming and reactive oxygen species (ROS) production, flow cytometry analysis was conducted. Furthermore, an ovariectomized (OVX) rat model was employed to assess the therapeutic efficacy of SPIO:Eu@PLGA nanospheres in preventing the deterioration of osteoporosis. In vitro, SPIO:Eu@PLGA nanospheres significantly attenuated M1 macrophage activation induced by lipopolysaccharides, promoting a shift towards the M2 phenotype. This action is linked to the modulation of ROS and the NF-κB pathway. Unlike free Eu ions, which do not achieve similar results when not incorporated into the SPIO nanocrystals. SPIO:Eu@PLGA nanospheres enhanced osteoblast differentiation and matrix mineralization while inhibiting RANKL-induced osteoclastogenesis. In vivo studies demonstrated that SPIO:Eu@PLGA nanospheres effectively targeted trabecular bone surfaces in OVX rats under magnetic guidance, preserving their structure and repairing trabecular bone loss by modulating macrophage polarization, thus restoring bone remodeling homeostasis. The study underscores the critical role of Eu doping in boosting the anti-osteoporotic effects of SPIO:Eu@PLGA nanospheres, evident at both cellular and tissue levels in vitro and in vivo. The inclusion of Eu into SPIO matrix suggests a novel approach for developing more effective osteoporosis treatments, particularly for conditions induced by OVX. This research provides essential insights into SPIO:Eu@PLGA nanospheres as an innovative osteoporosis treatment, addressing the limitations of conventional therapies through targeted delivery and macrophage polarization modulation.