Induced M2 Macrophage Research Articles

Activated hepatic stellate cell-derived small extracellular vesicles facilitate M2 macrophage polarization and hepatoma progression via miR-27a-3p

The progression of hepatoma is heavily influenced by the microenvironment. Tumor-associated macrophages (TAMs) are considered to play a critical role in the tumor microenvironment (TME) and increase the aggressiveness of hepatoma. The activation of hepatic stellate cells (HSCs) is involved in hepatoma progression, and accumulating evidence demonstrates a change in microRNA (miRNA) expression during HSC activation. Therefore, the potential roles of HSCs-related miRNAs in macrophage differentiation and hepatoma progression deserve to be explored. The present study aimed to investigate the effects of miRNAs carried by small extracellular vesicles (sEVs) released by activated HSCs on hepatoma progression. The results indicated that miR-27a-3p was significantly upregulated in cells and corresponding sEVs during the activation of primary rat HSCs and human HSC line-LX2 cells. Furthermore, miR-27a-3p contributed to the proliferation and migration of hepatoma cells and promoted M2 polarization of macrophage. HSC-sEVs overexpressing miR-27a-3p can directly facilitate tumor progression and modulate macrophage polarization, indirectly contributing to hepatoma progression. Finally, Sprouty2 (SPRY2) was verified to be the target gene of miR-27a-3p. In conclusion, activated HSC-derived sEVs with high levels of miR-27a-3p might induce M2 macrophage polarization and promote hepatoma progression, providing new insights into the mechanism of hepatoma progression.

Locally Injectable, ROS-Scavenging, and ROS-/pH-Responsive Polymeric-Micelles-Embedded Hydrogels for Precise Minimally Invasive and Long-Lasting Rheumatoid Therapy.

Rheumatoid arthritis (RA) is a chronic autoimmune disease characterized by synovitis, bone-erosion, and joint-destruction. Here, we developed a locally injectable, ROS-scavenging, and ROS-/pH-responsive drug-delivery platform (HC@PTM) by bio-compositing of aldolizing hyaluronic acid (HA) crosslinked with chitosan (CS), and ROS-triggered/eliminated micelles (PTM) coupled with the drug methotrexate(MTX). The PTM efficiently eradicate excessive ROS in RA-joints, precisely triggering drug-release within inflamed arthritic-sites and further confer exceptional antioxidant origins to HC@PTM. HC@PTM with outstanding shape-adaptability and self-repairing properties effectively conformed to irregular articular cartilage while resisting joint-induced deformations. Further, the platform's pH-responsive nature enables on-demand drug-release within acidic inflamed synovium, serving as a drug-reservoir for precise and sustained therapeutic effects. Extensive in vitro and in vivo investigations confirm HC@PTM's ability to induce M2 macrophage polarization, downregulate inflammatory factor expression, and ameliorate the RA-microenvironment, ultimately achieving synergistic therapeutic outcomes. This study represents significant advancements in precise and long-term RA-treatment through a minimally invasive approach, offering potential strategies for novel precision medicine.

Bone marrow mesenchymal stem cell-derived exosomal miR-181a-5p promotes M2 macrophage polarization to alleviate acute pancreatitis through ZEB2-mediated RACK1 ubiquitination.

As a common digestive disease, acute pancreatitis (AP) often threatens the life of patients. Bone marrow mesenchymal stem cells (BMSCs) derived exosomes have exhibited some benefits for AP. However, the mechanism remains unclear and deserves to be further investigated. The characteristics of BMSCs-exosomes (BMSCs-Exos) were identified. The abundance of genes and proteins was evaluated using quantitative real-time PCR (RT-qPCR), western blot, enzyme-linked immunosorbent assay (ELISA) and IF assay. Cell apoptosis and CD206-positive cells were measured by flow cytometry. The interactions among miR-181a-5p, Zinc finger E-box binding homeobox2 (ZEB2) and Receptor for Activated C Kinase 1 (RACK1) were verified using dual luciferase reporter assay, RNA immunoprecipitation (RIP), coimmunoprecipitation (Co-IP). BMSCs-Exos effectively improved AP injury through restraining AR42J cell apoptosis and promoting M2 macrophage polarization, which was realized due to BMSCs-Exos harboring an abundance of miR-181a-5p. Further experiments validated miR-181a-5p silenced ZEB2 and ZEB2 reduced RACK1 expression through mediating RACK1 ubiquitination. ZEB2 knockdown decreased AR42J cell apoptosis and induced M2 macrophage polarization to alleviate AP injury, whereas RACK1 downregulation abolished these phenomena. BMSCs-Exos harboring miR-181a-5p suppressed AR42J cell apoptosis and promoted M2 macrophage polarization to delay AP progression through ZEB2-mediated RACK1 ubiquitination.

Transglutaminase 2 inhibition ameliorates cardiac fibrosis in myocardial infarction by inducing M2 macrophage polarization in vitro and in vivo

Objective: Macrophages perform vital functions in cardiac remodeling after myocardial infarction (MI). Transglutaminase 2 (TG2) participates in fibrosis. Nevertheless, the role of TG2 in MI and mechanisms underlying macrophage polarization are unclear. This study aimed to discover the functions and possible mechanisms of TG2 in MI. Material and Methods: C57BL/6 mice were classified into three groups (six mice per group): Sham, MI, and MI+GK921 groups. GK921 acts as a TG2 inhibitor. Cardiac function, myocardial cell apoptosis, fibrosis, and macrophage phenotype in mouse experiments were detected through echocardiography, terminal deoxynucleotidyl transferase dUTP nick end labeling, Masson staining, immunofluorescence, and flow cytometry, respectively. The in vitro study involved the treatment of mouse cardiac fibroblasts isolated from mice with transforming growth factor β1 (TGF-β1) and evaluation of fibrosis through the detection of the expressions of fibrosis-associated proteins using Western blot. Bone marrow-derived macrophages (BMDMs) obtained from mice were triggered by interleukin (IL)-4, and the type of macrophages was determined through flow cytometry. Results: In in vivo experiments, GK921 substantially improved cardiac injury and fibrosis, induced M2 macrophage polarization, and suppressed the TGF-β1/small mother against decapentaplegic 3 (Smad3) pathway in MI mice. Moreover, TG2 knockdown considerably decreased the expressions of fibrosis-associated proteins in TGF-β1-triggered mouse cardiac fibroblasts, which indicates the repressive effect of TG2 knockdown on fibrosis. In addition, the inhibition effect of TG2 downregulation on the TGF-β1/Smad3 pathway was proven in TGF-β1-treated mouse cardiac fibroblasts in vitro. Moreover, TG2 inhibition remarkably increased M2 macrophage polarization in IL-4-induced BMDMs. Conclusion: TG2 inhibition facilitated M2 macrophage polarization to provide protection against MI-caused cardiac fibrosis in mice, and these effects may be attained through modulation of the TGF-β1/Smad3 pathway.

Norepinephrine stimulates M2 macrophage polarization via β2-adrenergic receptor-mediated IL-6 production in breast cancer cells

Previous studies have demonstrated that norepinephrine (NE) released during chronic stress promotes breast cancer (BC) metastasis via adrenergic receptors (ARs). However, the effect of NE on tumor-associated macrophage polarization and the underlying mechanisms remain largely unknown. In this study, we aimed to investigate the influence of NE on M2 macrophage polarization, with a particular focus on the crosstalk between macrophages and BC cells. Our results demonstrated that, although NE alone did not directly induce the expression of M2 macrophage markers, conditioned medium from NE-treated MDA-MB-231 human BC cells (NE CM) significantly promoted M2 macrophage polarization in THP-1 macrophages. We found that NE stimulated IL-6 production in MDA-MB-231 cells via β2-AR/NF-κB pathway, which activated STAT3 in THP-1 cells to induce M2 macrophage polarization. NE failed to induce IL-6 production and NF-κB activation when ADRB2 was knocked down in MDA-MB-231 cells. Furthermore, ADRB2 knockdown in cancer cells suppressed NE CM-induced M2 macrophage polarization, as well as M2 macrophage-induced cancer cell migration. Taken together, our results suggest that NE stimulates M2 macrophage polarization by inducing IL-6 secretion from BC cells through a β2-AR-dependent mechanism, which subsequently promotes cancer cell migration. Targeting β2-AR may represent a promising strategy to prevent chronic stress-induced BC metastasis.

In situ licensing of mesenchymal stem cell immunomodulatory function via BMP-2 induced developmental process

The immunomodulatory function of mesenchymal stem cells (MSCs) is plastic and susceptible to resident microenvironment in vivo or inflammatory factors in vitro. We propose a unique method to enhance the immunoregulatory functions of mesenchymal stem cells (MSCs) through an artificially controllable in vivo inflammatory microenvironment generated by biomaterials loaded with BMP-2 that induce bone development. MSCs activated through this method effectively induce M1 macrophage polarization toward the M2 phenotype, promote differentiation of naïve T cells into regulatory T cells, and inhibit the proliferation of activated T cells via prostaglandin E2 (PGE2) secretion. This in vivo licensing not only preserves the immunogenicity of MSCs but also alters DNA methylation patterns, enabling MSCs to exhibit immunoregulatory effects with epigenetic memory. Validation in a mouse colitis model demonstrated their therapeutic efficacy and long-term viability. Furthermore, we found that the material composition influences the inflammatory response during development, with polysaccharide-based biomaterials proving advantageous over protein-based materials in establishing an inflammatory niche conducive to MSC activity. These findings underscore the potential of tissue engineering to create in vivo environments that license MSCs, offering a strategic avenue to enhance MSC-based therapies for addressing significant immune disorders.

Polyamine-Enriched Exosomes from Leishmania donovani Drive Host Macrophage Polarization via Immunometabolism Reprogramming.

Leishmania donovani (Ld) promastigotes secrete exosomes that are crucial in host-pathogen interactions and intercellular communication by carrying parasite-specific molecules. Although the composition of cargos in Leishmania exosomes is known, the effects of the unique metabolic repertoire on immunometabolism rewiring of macrophage polarization are poorly understood. Interestingly, we found the enrichment of polyamines (PAs) such as spermidine and putrescine in the Ld-exosomes. Herein, we investigate the critical polycationic molecules and their crucial role in parasite survival. Our study shows that PA inhibition or depletion significantly impairs parasite growth and fitness, particularly in drug-resistant strains. Furthermore, we aimed to elucidate the impact of PAs-enriched Ld-exosomes on host macrophages. The data demonstrated that macrophages efficiently internalized these exosomes, leading to heightened phagocytic activity and infectivity. In addition, internalized Ld-exosomes induced M2 macrophage polarization characterized by elevated Arginase-1 expression and activity. The increased expression of the solute carrier gene (SLC3A2) and elevated intracellular spermidine levels suggest that Ld-exosomes contribute to the host PAs pool and create an anti-inflammatory milieu. These findings highlight the essential role of PAs-enriched Ld-exosomes in parasite survival and establishing a pro-parasitic environment in the host macrophage.

Low molecular weight fucoidan induces M2 macrophage polarization to attenuate inflammation through activation of the AMPK/mTOR autophagy pathway

Fucoidan, a sulfated polysaccharide with a complex structure, has gradually become the focus of biomedical research due to its remarkable biological activity and low toxicity. In this research, it was noted that low molecular weight fucoidan (LMWF) exhibited significant antimicrobial effects on Methicillin-resistant Staphylococcus aureus (MRSA) and promoted polarization towards M2 macrophages, leading to a substantial reduction in inflammatory responses within the lipopolysaccharide (LPS)-activated macrophages. We further explored the mechanism underlying the anti-inflammation activity. Our findings indicated that LMWF significantly enhanced the phosphorylation level of AMP-activated protein kinase (AMPK), inhibited the phosphorylation of the mammalian target of rapamycin (mTOR), and enhanced the expression of LC3II. Meanwhile, Compound C (CC) substantially reversed the anti-inflammation effect of LMWF, indicating that the AMPK pathway plays a pivotal role in this effect. In in vivo research, LMWF revealed impressive anti-inflammatory potential. LMWF treatment significantly eliminated MRSA and ameliorated inflammatory symptoms in mice's MRSA-infected skin wound model. Further analysis using Western Blot (WB) indicated significant AMPK/mTOR signaling pathway activation in mice treated with LMWF, which led to accelerated polarization of macrophages from the M1 to the M2 phenotype. In summary, we systematically explored the mechanism by which LMWF exerts anti-inflammatory effects through in vitro and in vivo experiments. It was confirmed that LMWF effectively induced the conversion of macrophages to an anti-inflammatory M2 phenotype by activating the AMPK/mTOR pathway. Simultaneously, LMWF effectively eradicated MRSA and accelerated wound healing in mice. This finding provides an important theoretical basis for further research on fucoidan.

Subcutaneously transplanted xenogeneic protein recruits treg cells and M2 macrophages to induce browning of inguinal white adipose tissue.

To study whether subcutaneously embedding xenogeneic protein threads or synthetic polymer absorbable threads can improve obesity phenotypes and metabolic conditions, and to further explore its underlying mechanism. Thirty-six 8-week-old ob/ob mice were randomly allocated to three groups, respectively, receiving catgut embedding, PGA thread embedding or sham treatment bilaterally to the groin. Individual parameters including weight, food intake, and core temperature are recorded and metabolism assessment, energy expenditure analysis, and PET/CT scanning are also performed at fixed timepoints. After surgical incision, the inguinal white adipose tissue was histologically examined and its expression profile was tested and compared among groups 4 weeks and 12 weeks after operation. Catgut embedding reduced weight gain and improved metabolic status in ob/ob mice. Browning of bilateral inguinal WAT (white adipose tissue) was induced after catgut embedding, with massive infiltration of Treg cells and M2 macrophages in the tissue slices of fat pads. IL-10 and TGF-β released by Treg cells targeted macrophages and the induced M2 macrophages increased the expression of thermogenic and anti-inflammatory genes in fat. The secretion of catecholamines by polarized M2 macrophages led to the activation of β3-AR-related pathways in adipocytes and the browning of adipose tissue. Abdominal subcutaneous catgut embedding has the potential to combat obesity through the induction of WAT browning mediated by infiltrated Treg cells and macrophages.

Paricalcitol ameliorates diabetic nephropathy by promoting EETs and M2 macrophage polarization and inhibiting inflammation by regulating VDR/CYP2J2 axis.

Previous studies have shown that paricalcitol (PA) has a protective effect on the kidneys. However, the exact molecular mechanism by which PA affects diabetic nephropathy (DN) progression remains uncertain. PBMCs of patients with DN were isolated, and CYP2J2 and VDR levels were detected by qPCR. Pearson correlation analysis was utilized to detect the relationship between uACR and CYP2J2 and VDR and between CYP2J2 and VDR. The protective effects of PA on DN have been examined by TUNEL, HE staining, ELISA, and Flow cytometry assays in STZ-induced mice. Moreover, THP-1 cells were stimulated with HG/LPS for invitro studies. ELISA, qPCR, western blot, and Flow cytometry assays were utilized to assess the effects of PA on DN progression by regulating CYP2J2. The interaction between CYP2J2 and VDR was analyzed by CHIP-qPCR and luciferase experiments. CYP2J2 and VDR levels were downregulated and uACR level was upregulated in DN patients. CYP2J2 and VDR were positively correlated in PBMCs. Both CYP2J2 and VDR are inversely correlated with uACR. Moreover, after PA treatment, 11, 12-EET levels increased, inflammatory factor levels decreased, and M2 macrophage polarization was promoted in STZ-induced mice and HG/LPS-triggered THP-1 cells. Depletion of CYP2J2 and VDR decreased 11, 12-EET level, enhanced inflammatory factor levels, and inhibited M2 macrophage polarization, which were reversed by CYP2J2 overexpression in HG/LPS-treated cells. Furthermore, VDR bound to the CYP2J2 promoter and promoted CYP2J2 transcriptional expression. The present work pointed out a new use for PA to inhibit DN progression by increasing EET level, inhibiting inflammatory response, and inducing M2 macrophage polarization via regulating the VDR/CYP2J2 axis.

Zinc-based Polyoxometalate Nanozyme Functionalized Hydrogels for optimizing the Hyperglycemic-Immune Microenvironment to Promote Diabetic Wound Regeneration.

In diabetic wounds, hyperglycemia-induced cytotoxicity and impaired immune microenvironment plasticity directly hinder the wound healing process. Regulation of the hyperglycemic microenvironment and remodeling of the immune microenvironment are crucial. Here, we developed a nanozymatic functionalized regenerative microenvironmental regulator (AHAMA/CS-GOx@Zn-POM) for the effective repair of diabetic wounds. This novel construct integrated an aldehyde and methacrylic anhydride-modified hyaluronic acid hydrogel (AHAMA) and chitosan nanoparticles (CS NPs) encapsulating zinc-based polymetallic oxonate nanozyme (Zn-POM) and glucose oxidase (GOx), facilitating a sustained release of release of both enzymes. The GOx catalyzed glucose to gluconic acid and (H₂O₂), thereby alleviating the effects of the hyperglycemic microenvironment on wound healing. Zn-POM exhibited catalase and superoxide dismutase activities to scavenge reactive oxygen species and H₂O₂, a by-product of glucose degradation. Additionally, Zn-POM induced M1 macrophage reprogramming to the M2 phenotype by inhibiting the MAPK/IL-17 signaling diminishing pro-inflammatory cytokines, and upregulating the expression of anti-inflammatory mediators, thus remodeling the immune microenvironment and enhancing angiogenesis and collagen regeneration within wounds. In a rat diabetic wound model, the application of AHAMA/CS-GOx@Zn-POM enhanced neovascularization and collagen deposition, accelerating the wound healing process. Therefore, the regenerative microenvironment regulator AHAMA/CS-GOx@Zn-POM can achieve the effective conversion of a pathological microenvironment to regenerative microenvironment through integrated control of the hyperglycemic-immune microenvironment, offering a novel strategy for the treatment of diabetic wounds.

S100A9 regulates M1 macrophage polarization and exacerbates steatotic liver ischemia-reperfusion injury

ObjectiveSteatotic livers exhibit higher susceptibility to ischemia reperfusion (IR) injury, which increase the risk of primary graft non-function following liver transplantation. S100A9 is identified as a pivotal innate immune sensor that regulates the progression of liver diseases. However, its significance in steatotic liver IR injury remains under-investigated. MethodsIn mice model, we generated S100A9 knockout (S100A9 KO) mice to investigate the role of S100A9 in IR-stimulated steatotic livers. In vitro, primary bone marrow-derived macrophages were utilized to explore the effect of S100A9 in regulating macrophage polarization and inflammation. ResultsS100A9 expression was markedly increased in steatotic livers of mice subjected to IR insult. S100A9 deletion significantly attenuated liver inflammatory injury, as evidenced by the diminished infiltration of both monocytes/macrophages and neutrophils (p < 0.05). The expression of proinflammatory factors was reduced (p < 0.05) at the same time. Additionally, S100A9-deficient livers demonstrated M1 polarization decrease and Toll-like receptor 4 (TLR4) suppression (p < 0.05). In vitro, genetic TLR4 inhibition led to nuclear factor kappa B (NF-κB) inactivation and subsequent M1 polarization decrease (p < 0.05) in macrophages treated with recombinant S100A9. ConclusionIn this study, we highlight the pivotal role of TLR4/NF-κB as a critical mediator of S100A9 in inducing M1 macrophage polorization- dependent inflammation in steatotic livers IR injury.

Immune-response gene 1 deficiency aggravates inflammation-triggered cardiac dysfunction by inducing M1 macrophage polarization and aggravating Ly6Chigh monocyte recruitment

The immune response gene 1 (IRG1) and its metabolite itaconate are implicated in modulating inflammation and oxidative stress, with potential relevance to sepsis-induced myocardial dysfunction (SIMD). This study investigates their roles in SIMD using both in vivo and in vitro models. Mice were subjected to lipopolysaccharide (LPS)-induced sepsis, and cardiac function was assessed in IRG1 knockout (IRG1-/-) and wild-type mice. Exogenous 4-octyl itaconate (4-OI) supplementation was also examined for its protective effects. In vitro, bone marrow-derived macrophages and RAW264.7 cells were treated with 4-OI following Nuclear factor, erythroid 2 like 2 (NRF2)–small interfering RNA administration to elucidate the underlying mechanisms. Our results indicate that IRG1 deficiency exacerbates myocardial injury during sepsis, while 4-OI administration preserves cardiac function and reduces inflammation. Mechanistic insights reveal that 4-OI activates the NRF2/HO-1 pathway, promoting macrophage polarization and attenuating inflammation. These findings underscore the protective role of the IRG1/itaconate axis in SIMD and suggest a therapeutic potential for 4-OI in modulating macrophage responses.

The magnesium-doped CSH/BCP promotes alveolar bone regeneration by mediating M2 macrophage polarization via miR-21–5p/Smad2 axis

The repair of alveolar bone defects is a complex biological process that involves the interplay between implant materials, bone marrow mesenchymal stem cells (BMSCs), and the immune cells present in the surrounding area. Moreover, the polarization of macrophages induced by implant materials has been shown to play a crucial role in regulating bone regeneration. Recent studies have discovered that M2 macrophages promote the osteogenic differentiation of BMSCs by activating the TGF-β/BMP signaling pathway. However, the molecular mechanisms underlying the regulation of bone regeneration in BMSCs by macrophages remain unclear. Our in vivo study demonstrated that a 10 % magnesium (Mg2+)-doped calcium sulfate hemihydrate -biphasic calcium phosphate (CSH/BCP) composite ceramic material was effective in repairing alveolar bone defects in rabbits. In our in vitro study, we observed that this ceramic material could induce M2 macrophage polarization and reduce inflammation. Moreover, the conditioned media obtained from M2 macrophages promoted the osteogenic differentiation of BMSCs. Additionally, our research showed that overexpression of miR-21–5p inhibited M2 macrophage polarization and reduced the osteogenic differentiation capacity of BMSCs. Co-overexpression of miR-21–5p and Smad2 in macrophages partially reversed the effects of miR-21–5p on the osteogenic differentiation of BMSCs and macrophage polarization. These findings suggested that Mg2+-doped CSH/BCP composite ceramic materials could enhance M2 macrophage polarization through the miR-21–5p/Smad2 axis, and the microenvironment of M2 macrophages could further promote the osteogenic differentiation of BMSCs. The findings presented in this work offer valuable insights into the molecular mechanisms that regulate bone regeneration in BMSCs and the role of macrophages in this process.

Anti-inflammatory effects of MerTK by inducing M2 macrophage polarization via PI3K/Akt/GSK-3β pathway in gout

Mer tyrosine kinase (MerTK) has been found to regulate the secretion of inflammatory factors and exert immunosuppressive effects, but its role in gout remains unclear. In this study, we aimed to clarify the immnue effects of MerTK in gout. MerTK in synovium or serum of gout patients was determined by immunohistochemistry, enzyme-linked immunosorbent assay (ELISA), and real-time quantitative polymerase chain reaction (RT-qPCR). In monosodium urate (MSU)-induced gout mice, the effect of MerTK inhibitor (UNC2250) on inflammation and polarization was also assessed. After inhibition, knockdown or overexpression of MerTK, inflammatory response and polarization level in THP1-derived macrophages were evaluated by RT-qPCR and flow cytometry. Regulation of MerTK inhibitors on mitochondrial function and downstream pathway in THP1-derived macrophages were detected. MerTK in synovium and serum of gout patients were increased. MerTK inhibitor stimulated the inflammation and M1 polarization in MSU-induced gout mice. MerTK inhibition, knock-down, or overexpression affected inflammatory response, polarization and mitochondrial function in vitro in gout model. The PI3K/Akt/GSK-3β pathway was identified to reduce after MerTK inhibition and the relevant results were as expected, validated by knock-down or overexpressing MerTK. In conclusion, MerTK was detected to increase in both gout patients and model. MerTK influenced inflammatory response and polarization markers through PI3K/Akt/GSK-3β pathway. Interfering MerTK/PI3K/Akt/GSK-3β axis may provide a new therapeutic target for gout.

The Nf1-Q181X point mutation induces M2 macrophage polarization via the AKT/STAT pathway to promote smooth muscle cell proliferation and migration.

Increased case reports have shown that patients with NF1 have an increased risk of extensive vascular vasculopathy. Previous studies demonstrated the presence of macrophages and smooth muscle cells in the neoplastic intima of carotid arteries after injury in Nf1+/- mice. However, whether NF1 gene mutations affect macrophage polarization and macrophage-smooth muscle cell interactions remains to be elucidated. Scratch assay and transwell assay were utilized to detect cell migration ability. The dye 2',7'dichlorofluorescin diacetate and neutral red stain were used to assess intracellular ROS production and cell phagocytosis function, respectively. Proteins and mRNA expression were determined by western blot, RT-qPCR, and immunofluorescence. Finally, the macrophage (MAC) and vascular smooth muscle cell (VSMC) co-culture system was used to detect cellular crosstalk. Cell function assays confirmed that the Nf1-Q181X point mutation attenuated the phagocytosis of bone marrow-derived macrophages (BMDMs) and promoted the migration and ROS production of BMDMs. Moreover, we found that the Nf1-Q181X point mutation inhibited M1 but promoted M2 macrophage polarization by down-regulating p38, ERK, and JNK and up-regulating the Akt/STAT3 signaling pathway, respectively. Furthermore, in the MAC-VSMC co-culture system, we demonstrated that Nf1-Q181X point mutation-activated M2 BMDMs promoted proliferation and migration of VSMCs and induced the transformation of VSMCs from contractile phenotype to synthetic phenotype. The findings suggest that the Nf1-Q181X point mutation can mediate macrophage polarization and promote smooth muscle cell proliferation and migration, providing clinical clues for the treatment of NF1-complicated vasculopathy.

Exosomal LINC00958 maintains ovarian cancer cell stemness and induces M2 macrophage polarization via Hedgehog signaling pathway and GLI1 protein

Long non-coding RNA (lncRNA) LINC00958 has been reported to promote many gynecological cancers, but its detailed function in OC remains unclear. Cancer stem cells (CSCs) and tumor-associated macrophages (TAMs) have been reported to participate in the occurrence and metastasis of cancers. We want to explore the effects of exosomal LINC00958 on cell stemness and macrophage polarization in OC. LINC00958 expression was first verified in OC cells and its function on cell stemness was verified by subcellular fractionation analysis, sphere formation assay and so on. Exosomal LINC00958 was secreted from OC cells and the model of M2 macrophage polarization was established to further verify the impact of exosomal LINC00958 on the cell stemness and macrophage polarization of OC cells using several mechanism experiments including flow cytometry, RNA pulldown, luciferase reporter assays and so on. LINC00958 was up-regulated in OC cells and exosomal LINC00958 enhanced the stem cell-like properties of OC cells and M2 macrophage polarization. Furthermore, LINC00958 combined with glioma-associated oncogene homolog 1 (GLI1) to activate Hedgehog pathway, thereby promoting M2 polarization. Exosomal LINC00958 maintained OC cell stemness and induced M2 polarization via the Hedgehog signaling pathway.

Areca nut-induced metabolic reprogramming and M2 differentiation promote OPMD malignant transformation

BackgroundBetel quid and its major ingredient, areca nut, are recognized by IARC as major risk factors in oral cancer development. Areca nut extract (ANE) exposure has been linked to OPMD progression and malignant transformation to OSCC. However, the detailed mechanism through which ANE acts on other cell types in the oral microenvironment to promote oral carcinogenesis remains elusive.MethodsImmunoprofiling of macrophages associated with OPMD and OSCC was carried out by immunohistochemical and immunofluorescence staining. Phosphokinase and cytokine arrays and western blotting were performed to determine the underlying mechanisms. Transwell assays were used to evaluate the migration-promoting effect of ANE. Hamster model was finally applied to confirm the in vivo effect of ANE.ResultsWe reported that M2 macrophages positively correlated with oral cancer progression. ANE induced M2 macrophage differentiation, CREB phosphorylation and VCAM-1 secretion and increased mitochondrial metabolism. Conditioned medium and VCAM-1 from ANE-treated macrophages promoted migration and mesenchymal phenotypes in oral precancer cells. In vivo studies showed that ANE enhanced M2 polarization and related signaling pathways in the oral buccal tissues of hamsters.ConclusionOur study provides novel mechanisms for areca nut-induced oral carcinogenesis, demonstrating that areca nut promotes M2 macrophage differentiation and secretion of oncogenic cytokines that critically activate malignant transformation of oral premalignant cells.

β,β-Dimethylacrylalkannin, a Natural Naphthoquinone, Inhibits the Growth of Hepatocellular Carcinoma Cells by Modulating Tumor-Associated Macrophages.

Tumor-associated macrophages (TAMs) are pivotal in the tumor microenvironment (TME) of hepatocellular carcinoma (HCC), influencing various stages from initiation to metastasis. Understanding the role of TAMs in HCC is crucial for developing novel therapeutic strategies. Macrophages exhibit plasticity, resulting in M1 and M2 phenotypes, with M1 macrophages displaying antitumor properties and M2 macrophages promoting tumor progression. Targeting TAMs to alter their polarization could offer new avenues for HCC treatment. β,β-dimethylacrylalkannin (DMAKN), a natural naphthoquinone, has gained attention for its antitumor properties. However, its impact on TAMs modulation remains unclear. This study investigates DMAKN's modulation of TAMs and its anti-HCC activity. Using an in vitro model with THP-1 cells, we induced M1 macrophages with LPS/IFN-γ and M2 macrophages with IL-4/IL-13, confirming polarization with specific markers. Co-culturing these macrophages with HCC cells showed that M1 cells inhibited HCC growth, while M2 cells promoted it. Screening for non-toxic DMAKN concentrations revealed its ability to induce M1 polarization and enhance LPS/IFN-γ-induced M1 macrophages, both showing anti-HCC effects. Conversely, DMAKN suppressed IL-4/IL-13-induced M2 polarization, inhibiting M2 macrophages' promotion of HCC cell viability. In summary, DMAKN induces and enhances M1 polarization while inhibiting M2 polarization of macrophages, thereby inhibiting HCC cell growth. These findings suggest that DMAKN has the potential to regulate TAMs in HCC, offering promise for future therapeutic development.

Sciatic nerve stimulation alleviates neuropathic pain and associated neuroinflammation in the dorsal root ganglia in a rodent model

BackgroundSatellite glial cells (SGCs) in the dorsal root ganglia (DRG) play a pivotal role in the formation of neuropathic pain (NP). Sciatic nerve stimulation (SNS) neuromodulation was reported to alleviate NP and reduce neuroinflammation. However, the mechanisms underlying SNS in the DRG remain unclear. This study aimed to elucidate the mechanism of electric stimulation in reducing NP, focusing on the DRG.MethodsL5 nerve root ligation (NRL) NP rat model was studied. Ipsilateral SNS performed 1 day after NRL. Behavioral tests were performed to assess pain phenotypes. NanoString Ncounter technology was used to explore the differentially expressed genes and cellular pathways. Activated SGCs were characterized in vivo and in vitro. The histochemical alterations of SGCs, macrophages, and neurons in DRG were examined in vivo on post-injury day 8.ResultsNRL induced NP behaviors including decreased pain threshold and latency on von Frey and Hargreaves tests. We found that following nerve injury, SGCs were hyperactivated, neurotoxic and had increased expression of NP-related ion channels including TRPA1, Cx43, and SGC-neuron gap junctions. Mechanistically, nerve injury induced reciprocal activation of SGCs and M1 macrophages via cytokines including IL-6, CCL3, and TNF-α mediated by the HIF-1α-NF-κB pathways. SNS suppressed SGC hyperactivation, reduced the expression of NP-related ion channels, and induced M2 macrophage polarization, thereby alleviating NP and associated neuroinflammation in the DRG.ConclusionsNRL induced hyperactivation of SGCs, which had increased expression of NP-related ion channels. Reciprocal activation of SGCs and M1 macrophages surrounding the primary sensory neurons was mediated by the HIF-1α and NF-κB pathways. SNS suppressed SGC hyperactivation and skewed M1 macrophage towards M2. Our findings establish SGC activation as a crucial pathomechanism in the gliopathic alterations in NP, which can be modulated by SNS neuromodulation.