M2 Macrophage Polarization Research Articles

IDH2 regulates macrophage polarization and tumorigenesis by modulating mitochondrial metabolism in macrophages

BackgroundTargeting the tumor microenvironment represents an emerging therapeutic strategy for cancer. Macrophages are an essential part of the tumor microenvironment. Macrophage polarization is modulated by mitochondrial metabolism, including oxidative phosphorylation (OXPHOS), the tricarboxylic acid (TCA) cycle, and reactive oxygen species content. Isocitrate dehydrogenase 2 (IDH2), an enzyme involved in the TCA cycle, reportedly promotes cancer progression. However, the mechanisms through which IDH2 influences macrophage polarization and modulates tumor growth remain unknown.MethodsIn this study, IDH2-deficient knockout (KO) mice and primary cultured bone marrow-derived macrophages (BMDMs) were used. Both in vivo subcutaneous tumor experiments and in vitro co-culture experiments were performed, and samples were collected for analysis. Western blotting, RNA quantitative analysis, immunohistochemistry, and flow cytometry were employed to confirm changes in mitochondrial function and the resulting polarization of macrophages exposed to the tumor microenvironment. To analyze the effect on tumor cells, subcutaneous tumor size was measured, and growth and metastasis markers were identified.ResultsIDH2-deficient macrophages co-cultured with cancer cells were found to possess increased mitochondrial dysfunction and fission than wild-type BMDM. Additionally, the levels of M2-associated markers decreased, whereas M1-associated factor levels increased in IDH2-deficient macrophages. IDH2-deficient macrophages were predominantly M1. Tumor sizes in the IDH2-deficient mouse group were significantly smaller than in the wild-type mouse group. IDH2 deficiency in macrophages was associated with inhibited tumor growth and epithelial–mesenchymal transition.ConclusionsOur findings suggest that IDH2 deficiency inhibits M2 macrophage polarization and suppresses tumorigenesis. This study underlines the potential contribution of IDH2 expression in macrophages and tumor microenvironment remodeling, which could be useful in clinical cancer research.

Inhibition of STAT3 by 2-Methoxyestradiol suppresses M2 polarization and protumoral functions of macrophages in breast cancer

BackgroundBreast cancer metastasis remains the leading cause of cancer-related deaths in women worldwide. Infiltration of tumor-associated macrophages (TAMs) in the tumor stroma is known to be correlated with reduced overall survival. The inhibitors of TAMs are sought after for reprogramming the tumor microenvironment. Signal transducer and activator of transcription 3 (STAT3) is well known to contribute in pro-tumoral properties of TAMs. 2-Methoxyestradiol (2ME2), a potent anticancer and antiangiogenic agent, has been in clinical trials for treatment of breast cancer. Here, we investigated the potential of 2ME2 in modulating the pro-tumoral effects of TAMs in breast cancer.MethodsTHP-1-derived macrophages were polarized to macrophages with or without 2ME2. The effect of 2ME2 on macrophage surface markers and anti-inflammatory genes was determined by Western blotting, flow cytometry, immunofluorescence, qRT‒PCR. The concentration of cytokines secreted by cells was monitored by ELISA. The effect of M2 macrophages on malignant properties of breast cancer cells was determined using colony formation, wound healing, transwell, and gelatin zymography assays. An orthotopic model of breast cancer was used to determine the effect of 2ME2 on macrophage polarization and metastasis in vivo.ResultsFirst, our study found that polarization of monocytes to alternatively activated M2 macrophages is associated with the reorganization of the microtubule cytoskeleton. At lower concentrations, 2ME2 treatment depolymerized microtubules and reduced the expression of CD206 and CD163, suggesting that it inhibits the polarization of macrophages to M2 phenotype. However, the M1 polarization was not significantly affected at these concentrations. Importantly, 2ME2 inhibited the expression of several anti-inflammatory cytokines and growth factors, including CCL18, TGF-β, IL-10, FNT, arginase, CXCL12, MMP9, and VEGF-A, and hindered the metastasis-promoting effects of M2 macrophages. Concurrently, 2ME2 treatment reduced the expression of CD163 in tumors and inhibited lung metastasis in the orthotopic breast cancer model. Mechanistically, 2ME2 treatment reduced the phosphorylation and nuclear translocation of STAT3, an effect which was abrogated by colivelin.ConclusionsOur study presents novel findings on mechanism of 2ME2 from the perspective of its effects on the polarization of the TAMs via the STAT3 signaling in breast cancer. Altogether, the data supports further clinical investigation of 2ME2 and its derivatives as therapeutic agents to modulate the tumor microenvironment and immune response in breast carcinoma.

Wnt7B enhances the osteogenic differentiation of lipopolysaccharide-stimulated human periodontal ligament stem cells and inhibits the M1 polarization of macrophages by binding FZD4

Wnt7B enhances the osteogenic differentiation of lipopolysaccharide-stimulated human periodontal ligament stem cells and inhibits the M1 polarization of macrophages by binding FZD4

Canine mesenchymal stem cell-derived exosomes attenuate renal ischemia-reperfusion injury through miR-146a-regulated macrophage polarization.

The most common factor leading to renal failure or death is renal IR (ischemia-reperfusion). Studies have shown that mesenchymal stem cells (MSCs) and their exosomes have potential therapeutic effects for IR injury by inhibiting M1 macrophage polarization and inflammation. In this study, the protective effect and anti-inflammatory mechanism of adipose-derived mesenchymal stem cell-derived exosomes (ADMSC-Exos) after renal IR were investigated. Initially, ADMSC-Exos were intravenously injected into IR experimental beagles, and the subsequent assessment focused on inflammatory damage and macrophage phenotype. Furthermore, an in vitro inflammatory model was established by inducing DH82 cells with LPS. The impact on inflammation and macrophage phenotype was then evaluated using ADMSC and regulatory miR-146a. Following the administration of ADMSC-Exos in IR canines, a shift from M1 to M2 macrophage polarization was observed. Similarly, in vitro experiments demonstrated that ADMSC-Exos enhanced the transformation of LPS-induced macrophages from M1 to M2 type. Notably, the promotion of macrophage polarization by ADMSC-Exos was found to be attenuated upon the inhibition of miR-146a in ADMSC-Exos. These findings suggest that miR-146a plays a significant role in facilitating the transition of LPS-induced macrophages from M1 to M2 phenotype. As a result, the modulation of macrophage polarization by ADMSC-Exos is achieved via the encapsulation and conveyance of miR-146a, leading to diminished infiltration of inflammatory cells in renal tissue and mitigation of the inflammatory reaction following canine renal IR.

The Immunosuppressive Receptor CD32b Regulation of Macrophage Polarization and Its Implications in Tumor Progression.

Macrophages, pivotal components of the immune system, orchestrate host defense mechanisms in humans and mammals. Their polarization into classically activated macrophages (CAMs or M1) and alternatively activated macrophages (AAMs or M2) dictates distinct functional roles in immunity and tissue homeostasis. While the negative regulatory role of CD32b within the FC gamma receptor (FCγR) family is recognized across various immune cell types, its influence on macrophage polarization remains elusive. This study aimed to elucidate the regulatory role of CD32b in macrophage polarization and discern the differential expression markers between the M1 and M2 phenotypes following CD32b siRNA transfection. The results revealed a decrease in the CD32b levels in lipopolysaccharide (LPS)-treated M1 and an increase in interleukin-4 (IL-4)-treated M2 macrophages, as observed in macrophage Raw264.7 cells. Furthermore, CD32b siRNA transfection significantly downregulated the M2 markers (IL-10, VEGF, Arg-1, and STAT6), while upregulating the M1 markers (IL-6, NF-κB, NOS2, and STAT1) in the Raw264.7 cells. Similar findings were recapitulated in macrophage-rich adherent cells isolated from mouse spleens. Additionally, the cytopathological analysis of pleural effusions and ascitic fluids from patients with cancer revealed a positive correlation between advanced tumor stages, metastasis, and elevated CD32b levels. In conclusion, this study highlights the regulatory influence of CD32b in suppressing M1 expression and promoting M2 polarization. Moreover, heightened M2 activation and CD32b levels appear to correlate with tumor progression. A targeted CD32b blockade may serve as a novel therapeutic strategy to inhibit M2 macrophage polarization and is promising for anti-tumor intervention.

QSOX1 exerts anti-inflammatory effects in sepsis-induced acute lung injury: Regulation involving EGFR phosphorylation mediated M1 polarization of macrophages

Sepsis is a systemic inflammatory response caused by an infection, which can easily lead to acute lung injury. Quiescin Q6 sulfhydryl oxidase 1 (QSOX1) is a sulfhydryl oxidase involved in oxidative stress and the inflammatory response. However, there are few reports on the role of QSOX1 in sepsis-induced acute lung injury (SALI). In this study, mice model of SALI was constructed by intraperitoneal injection with lipopolysaccharide (LPS). The increased inflammatory response and lactate dehydrogenase activity in bronchoalveolar lavage fluid (BALF) indicated successful modeling. Increased QSOX1 expression was both observed in lung tissues and lung macrophages of sepsis mice accompanied by increased polarization of M1-type macrophages. To explore the role of QSOX1 in the SALI, lentivirus containing QSOX1-specific overexpression or knockdown vectors were used to change QSOX1 expression in LPS-treated RAW264.7 cells. QSOX1 suppressed LPS-induced M1 polarization and further inhibited inflammatory response in RAW264.7 cells. Interestingly, the phosphorylation of epidermal growth factor receptor (EGFR), the promoter of M1 polarization in macrophages, was found to be downregulated upon QSOX1 overexpression in RAW264.7 cells. Mechanically, the binding of QSOX1 to EGFR protein promoted EGFR ubiquitination and degradation, thereby down-regulating EGFR phosphorylation. Moreover, inhibiting EGFR expression or its phosphorylation restored the impact of QSOX1 silencing on M1 polarization and inflammation in the LPS-treated RAW264.7 cells. In summary, QSOX1 may exert anti-inflammatory effects in SALI by inhibiting EGFR phosphorylation-mediated M1 macrophage polarization. This presented a potential target for the treatment and prevention of SALI.

The role of apoptosis, immunogenic cell death, and macrophage polarization in carbon ion radiotherapy for keloids: Targeting the TGF-β1/SMADs signaling pathway

Keloids, characterized by excessive extracellular matrix (ECM) deposition and aberrant fibrous tissue proliferation, present significant therapeutic challenges due to their recalcitrant and recurrent nature. This study explores the efficacy of Carbon Ion Radiotherapy (CIRT) as a novel therapeutic approach for keloids, focusing on its impact on fibroblast proliferation, apoptosis induction, immunogenic cell death (ICD), macrophage polarization, and the TGF-β/SMAD signaling pathway. Utilizing a murine model of keloid formed by subcutaneous injection of zeocin in C57BL/6 mice, we demonstrated that CIRT effectively reduces collagenous fiber synthesis and collagen production in keloid tissues. Further, CIRT was shown to inhibit keloid fibroblast proliferation and to induce apoptosis, as evidenced by increased expression of apoptosis-related proteins and confirmed through flow cytometry and TUNEL assay. Notably, CIRT induced mitochondrial stress, leading to enhanced immunogenicity of cell death, characterized by increased expression of ICD markers and secretion of interferon-γ. Additionally, CIRT promoted a shift from M2 to M1 macrophage polarization, potentially reducing TGF-β release and mitigating ECM deposition. Our findings suggest that CIRT mediates its therapeutic effects through the inhibition of the TGF-β/SMAD signaling pathway, thereby attenuating ECM formation and offering a promising avenue for keloid treatment. This study underscores the potential of CIRT as an innovative strategy for managing keloids, highlighting its multifaceted impact on key cellular processes involved in keloid pathogenesis.

Phosphorylated NPY1R regulates phenotypic transition of vascular smooth muscle cells, inflammatory response and macrophage infiltration to promote intracranial aneurysm progression

BackgroundRupture of intracranial aneurysm (IA) could give rise to spontaneous subarachnoid hemorrhage, leading to a high disability rate and even death. NPY1R expression was upregulated in aneurysm tissues of IA patients. However, the role and underlying mechanism of NPY1R remains unknown. MethodsThe IA model of mice was established using inducing systemic hypertension and injecting elastase. The expression of genes and proteins was detected by RT-qPCR and western blot. The number of T cells, macrophages, and neutrophils in IA mice was detected using flow cytometry and IF assay. The levels of inflammatory factors were measured using ELISA. Patho-morphology and inflammatory cells in aneurysm tissues were evaluated by HE staining. The interaction between TK and NPY1R was validated using Co-IP. ResultsNPY1R expression was greatly elevated in aneurysm tissues in IA patients and mice, which were positively related to macrophage infiltration. Besides, exogenous overexpression of NPY1R resulted in the promotion of contractile phenotype to the synthetic phenotype of vascular smooth muscle cells (VSMCs), inflammatory response and M1 macrophage polarization. In terms of the underlying mechanism, NPY1R protein could be modified by TK-mediated phosphorylation and TKI could decrease IA formation and suppresse contractile phenotype to synthetic phenotype of VSMCs, inflammatory response and M1 macrophage polarization in IA mice. Furthermore, ablating mouse macrophages abolished NPY1R overexpression-mediated promotion of IA formation and rupture in mice. ConclusionPhosphorylated NPY1R contributed to IA progression through promoting contractile phenotype to synthetic phenotype of VSMCs, inflammatory response and M1 macrophage polarization in IA.

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.

LncRNA-MM2P regulates retinal neovascularization through M2 macrophage polarization

The study aims to investigate the effects and potential mechanisms of lncRNA-MM2P on retinal neovascularization in a mouse model of oxygen-induced retinopathy (OIR). The OIR model was established in C57BL/6J mice. RAW264.7 cell line and bone marrow-derived macrophages (BMDMs) from mice were used for in vitro studies. RT-qPCR was used to analyze the expressions of lncRNA and mRNAs. The protein expression levels were determined by western blotting. The size of avascular areas and neovascular tufts were assessed based on isolectin B4 immunofluorescence staining images. The human retinal endothelial cells (HRECs) were used to evaluate the proliferation, migration, and tube formation of endothelial cells. The expression of lncRNA-MM2P was significantly upregulated from P17 to P25 in OIR retinas. Knockdown of lncRNA-MM2P levels in vivo led to a significant reduction in the neovascular tufts and avascular areas in the retinas of OIR mice. Knockdown of lncRNA-MM2P levels in vitro suppressed the expression of M2 markers in macrophages. Moreover, we found a significant inhibition of avascular areas and neovascular tufts in OIR mice injected intravitreally with M2 macrophages treated by shRNA-MM2P. The cellular functions of proliferation, migration, and tube formation were significantly attenuated in HRECs cultured with a supernatant of shRNA-MM2P-treated M2 macrophages. Our results indicate that lncRNA-MM2P regulates retinal neovascularization by inducing M2 polarization of macrophages in OIR mice. Therefore, lncRNA-MM2P may be a potential molecular target for immunoregulation of retinal neovascularization.

Abstract B053: Tumor-associated macrophages diminishes IL1RAP-targeting CAR-T cell therapy efficacy in Ewing sarcoma

Abstract Ewing sarcoma (EwS) is a pediatric malignancy of soft tissue and bone with a poor prognosis, especially in its metastatic stages. We have previously identified IL1RAP as a promising target for immunotherapies like chimeric antigen receptor (CAR) T cell therapy against EwS. However, CAR-T cells, despite their success in hematological cancers, often show limited efficacy against solid tumors. In orthotopic xenograft models of Ewing sarcoma (EwS) we have observed that CD11b+ CD206+ macrophages, known as tumor-associated macrophages (TAMs), surround the primary tumor. Treatment with IL1RAP-targeting CAR-T cells specific to EwS results in T cells localizing with these macrophages and failing to infiltrate the primary tumor. This study aims to characterize the impact of TAMs on CAR-T cell efficacy in EwS. We hypothesized that TAMs, polarized by Ewing sarcoma cells, suppress IL1RAP CAR-T cell activity. To model these interactions, we co-cultured EwS cells, macrophages, and CAR-T cells, performing luciferin-based in vitro cytotoxicity assays. THP-1 monocytes were differentiated into macrophages and polarized into M1 or M2 states using cytokines (LPS + IFN-y, IL-4 + IL-13), or differentiated into TAMs by co-culture with EwS cell lines. In vitro cytotoxicity assays were conducted using luciferase-expressing EwS target cells, polarized THP-1 macrophages, and IL1RAP CAR-T effector cells, with luminescence indicating EwS cell survival. We found that M1 macrophages did not affect CAR-T cell targeting of EwS cells, whereas M2 macrophages and TAMs significantly decreased specific lysis (p < 0.001). Conditioned media from polarized macrophages had no effect on CAR-T cell performance against EwS, suggesting that physical proximity or direct contact with TAMs is necessary to suppress CAR-T cell function. Western blot analysis of polarized THP-1 macrophages revealed that M2-polarized macrophages upregulated IL1RAP expression compared to M1 macrophages. Ongoing experiments aim to determine whether elevated IL1RAP expression in M2 macrophages redirects IL1RAP CAR-T cells away from EwS cells or if M2 macrophages mediate general suppression of CAR-T cell activity. Additionally, we are investigating whether THP-1-derived TAMs and primary macrophages also upregulate IL1RAP expression when polarized and how this affects syngeneic CAR-T cell performance. Our findings indicate that TAMs can influence the efficacy of IL1RAP-targeting CAR-T cells against EwS. Further investigation into the specific mechanisms responsible for this suppressive effect could enhance CAR-T therapy for Ewing sarcoma and potentially other solid tumors. Citation Format: Yue Zhou (Joe) Huang, Melanie Rouleu, Poul Sorensen. Tumor-associated macrophages diminishes IL1RAP-targeting CAR-T cell therapy efficacy in Ewing sarcoma [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Advances in Pediatric Cancer Research; 2024 Sep 5-8; Toronto, Ontario, Canada. Philadelphia (PA): AACR; Cancer Res 2024;84(17 Suppl):Abstract nr B053.

Sacubitril/valsartan alleviates myocardial infarction-induced inflammation in mice by promoting M2 macrophage polarisation via regulation of PI3K/Akt pathway

Background Macrophage polarisation-mediated inflammation plays a critical role in ventricular remodelling after myocardial infarction (MI). Sacubitril/Valsartan (Sac/Val) is an angiotensin receptor-neprilysin inhibitor that has shown beneficial effects on MI and heart failure. This study aims to further explore the mechanisms by which Sac/Val exerts its protective effects against MI. Methods A mouse MI model was induced by ligating the left anterior descending coronary artery, followed by Sac/Val administration. TTC staining and Masson trichrome staining were employed for estimating myocardial infarct size and fibrosis, respectively. The expression levels of proinflammatory factors were determined by ELISA and RT-qPCR. Flow cytometry and immunofluorescence staining were implemented to detect CD206-positive cell infiltration in mouse hearts. Western blotting was conducted to assess protein levels of Arg1, pro-fibrotic factors, and PI3K/Akt signalling-related markers. Results Sac/Val treatment reduced myocardial infarct size and fibrosis in mice after MI. Sac/Val administration decreased proinflammatory cytokine production and facilitated M2 macrophage polarisation in MI mouse cardiac tissues. Sac/Val activated PI3K/Akt signalling in MI mouse hearts. Blocking PI3K/Akt signalling counteracted Sac/Val-mediated protective effects in MI mice. Conclusion Sac/Val ameliorates MI-induced inflammation by facilitating M2 macrophage polarisation and activating PI3K/Akt signalling.

A carbon dot nanozyme hydrogel enhances pulp regeneration activity by regulating oxidative stress in dental pulpitis

Preserving pulp viability and promoting pulp regeneration in pulpitis have attracted widespread attention. Restricted by the oxidative stress microenvironment of dental pulpitis, excessive reactive oxygen and nitrogen species (RONS) trigger uncontrolled inflammation and exacerbate pulp tissue destruction. However, modulating redox homeostasis in inflamed pulp tissue to promote pulp regeneration remains a great challenge. Herein, this work proposes an effective antioxidative system (C-NZ/GelMA) consisting of carbon dot nanozymes (C-NZ) with gelatin methacryloyl (GelMA) to modulate the pulpitis microenvironment for dental pulp regeneration by utilizing the antioxidant properties of C-NZ and the mechanical support of an injectable GelMA hydrogel. This system effectively scavenges RONS to normalize intracellular redox homeostasis, relieving oxidative stress damage. Impressively, it can dramatically enhance the polarization of regenerative M2 macrophages. This study revealed that the C-NZ/GelMA hydrogel promoted pulp regeneration and dentin repair through its outstanding antioxidant, antiapoptotic, and anti-inflammatory effects, suggesting that the C-NZ/GelMA hydrogel is highly valuable for pulpitis treatment.

Perinatal exposure to PBEB aggravates liver injury via macrophage-derived TWEAK in male adult offspring mice under western diet

Liver injury and inflammation are the most commonly observed adverse outcomes following exposure to penta-brominated flame retardants (penta-BFRs). However, the role of inflammation in the development of liver injury in their alternatives has not yet been explored. Our study aimed to investigate the effects and the underlying mechanism of perinatal exposure to pentabromoethylbenzene (PBEB), a penta-BDE alternative, on liver injury in adult offspring mice under both chow and western diet in later life. Results showed that perinatal exposure to PBEB at 0.2 mg/kg or above led to liver injury in male offspring upon challenge with a western diet, but not in females. Utilizing the Olink immunology panel, our study specifically revealed an upregulation of tumor necrosis factor-related weak inducer of apoptosis (TWEAK) within the livers of male mice. This cytokine was further demonstrated to derive from the secretion by infiltrating macrophages in livers both in vivo and in vitro, which facilitated a shift towards M1 macrophage polarization. TWEAK further activated the hepatic NF-κB and NLRP3 inflammasome pathways, subsequently leading to hepatic pyroptosis in male mice of maternal PBEB exposure. Inhibition of TWEAK signaling mitigated macrophage polarization and inflammasome induction in a co-culture system of macrophages and liver cells. Our findings revealed that perinatal exposure to PBEB precipitated liver injury, partially through an inflammatory pathway mediated by macrophage-derived TWEAK, in male mice offspring under western diet.

Targeting SRSF10 might inhibit M2 macrophage polarization and potentiate anti-PD-1 therapy in hepatocellular carcinoma.

The efficacy of immune checkpoint blockade therapy in patients with hepatocellular carcinoma (HCC) remains poor. Although serine- and arginine-rich splicing factor (SRSF) family members play crucial roles in tumors, their impact on tumor immunology remains unclear. This study aimed to elucidate the role of SRSF10 in HCC immunotherapy. To identify the key genes associated with immunotherapy resistance, we conducted single-nuclear RNA sequencing, multiplex immunofluorescence, and The Cancer Genome Atlas and Gene Expression Omnibus database analyses. We investigated the biological functions of SRSF10 in immune evasion using in vitro co-culture systems, flow cytometry, various tumor-bearing mouse models, and patient-derived organotypic tumor spheroids. SRSF10 was upregulated in various tumors and associated with poor prognosis. Moreover, SRSF10 positively regulated lactate production, and SRSF10/glycolysis/ histone H3 lysine 18 lactylation (H3K18la) formed a positive feedback loop in tumor cells. Increased lactate levels promoted M2 macrophage polarization, thereby inhibiting CD8+ T cell activity. Mechanistically, SRSF10 interacted with the 3'-untranslated region of MYB, enhancing MYB RNA stability, and subsequently upregulating key glycolysis-related enzymes including glucose transporter 1 (GLUT1), hexokinase 1 (HK1), lactate dehydrogenase A (LDHA), resulting in elevated intracellular and extracellular lactate levels. Lactate accumulation induced histone lactylation, which further upregulated SRSF10 expression. Additionally, lactate produced by tumors induced lactylation of the histone H3K18la site upon transport into macrophages, thereby activating transcription and enhancing pro-tumor macrophage activity. M2 macrophages, in turn, inhibited the enrichment of CD8+ T cells and the proportion of interferon-γ+CD8+ T cells in the tumor microenvironment (TME), thus creating an immunosuppressive TME. Clinically, SRSF10 could serve as a biomarker for assessing immunotherapy resistance in various solid tumors. Pharmacological targeting of SRSF10 with a selective inhibitor 1C8 enhanced the efficacy of programmed cell death 1 (PD-1) monoclonal antibodies (mAbs) in both murine and human preclinical models. The SRSF10/MYB/glycolysis/lactate axis is critical for triggering immune evasion and anti-PD-1 resistance. Inhibiting SRSF10 by 1C8 may overcome anti-PD-1 tolerance in HCC.

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

To evaluate M1 and M2 macrophage polarization in radicular cysts and periapical granulomas through an immunohistochemical analysis and the correlation between macrophage polarization and histopathological diagnosis, clinical characteristics and lesion volume using cone-beam computed tomography. Periapical biopsies diagnosed as radicular cysts (n = 52) and periapical granulomas (n = 51) were analysed by immunohistochemical method. Teeth with periapical lesion with no history of root canal treatment (primary lesion) and lesions persistent to root canal treatment (persistent lesions) were included. Pathological diagnosis, patients' age, gender and clinical characteristics were obtained from treatment records. A cone-beam computed tomographic periapical volume index (CBCTPAVI) score was assigned to each periapical lesion based on the volume of the lesion. Immuno-expressions of CD68 and CD163 were quantified. The CD68/CD163 ratio was adopted to represent M1 or M2 macrophage polarization. Mann-Whitney U test was used to determine the different CD68/CD163 ratio between groups of radicular cyst and periapical granuloma. Spearman's correlation test was performed to assess the correlation between the CD68/CD163 ratio and lesion volume and CBCTPAVI score. Radicular cysts and periapical granulomas had CD68/CD163 median of 2.05 (IQR = 1.33) and 1.26 (IQR = 0.81), respectively. A significantly higher CD68/CD163 ratio was observed in radicular cysts (p < .001). In contrast, periapical granulomas had significantly lower median of CD68/CD163 ratio. Larger lesions had a higher median of CD68/CD163 ratio, while smaller lesions had lower median of CD68/CD163 ratio (p = .007, rs = .262). CD68/CD163 ratio was significantly correlated with the CBCTPAVI score in the overall periapical lesions (p = .002, rs = .306). The higher CD68/CD163 ratio in larger lesions indicated a higher degree of M1 polarization compared to smaller lesions. Regarding the pathological diagnosis, there was a significant positive correlation between CBCTPAVI score and CD68/CD163 ratio in periapical granulomas (p < .001, rs = .453), whereas the negative correlation was observed for radicular cysts (p < .001, rs = -.471). Periapical granulomas are characterized by a M2-dominant macrophage polarization, while radicular cysts have significantly higher M1 macrophages. The higher degree of M1 macrophage polarization was significantly correlated with larger volume and higher CBCTPAVI scores of overall periapical lesion and periapical granuloma.

Sequential Targeted Enzyme-Instructed Self-Assembly Supramolecular Nanofibers to Attenuate Intervertebral Disc Degeneration.

As an age-related disease, intervertebral disc degeneration is closely related to inflammation and aging. Inflammatory cytokines and cellular senescence collectively contribute to the degradation of intervertebral disc. Blocking this synergy reduces disc extracellular matrix damage caused by inflammation and aging. In this study, drug-loaded nanofibers with sequential targeting functions are constructed through intelligent response, hydrophilicity, and in situ self-assembly empowerment of flurbiprofen. The peptide precursor responds to the cleavage of overexpressed MMP-2 in the degenerative intervertebral disc microenvironment (intracellular and extracellular), resulting in the formation of self-assembled nanofibers that enable the on-demand release of flurbiprofen and COX-2 response. In vitro, Comp. 1 (Flurbiprofen-GFFYPLGLAGEEEERGD) reduces the expression of inflammation-related genes and proteins and the polarization of M1 macrophages by competitively inhibiting COX-2 and increases the expression of extracellular matrix proteins COL-2 and aggrecan. Additionally, it can reduce the expression of Senescence-Associated Secretory Phenotype and DNA damage in aged nucleus pulposus cells and promote the recovery of proliferation and cell cycle. In vivo, drug-loaded nanofibers delay intervertebral disc degeneration by inhibiting inflammation and preventing the accumulation of senescent cells. Therefore, the sequentially targeted self-assembled drug-loaded nanofibers can delay intervertebral disc degeneration by blocking the synergistic effect of inflammatory cytokines and cellular senescence.

Biomimetic Surface Nanoengineering of Biodegradable Zn‐Based Orthopedic Implants for Enhanced Biocompatibility and Immunomodulation

AbstractZinc (Zn) is gaining increased recognition as a biodegradable metal in biomedical applications but clinical translation is limited due to its poor biocompatibility. This study addresses these issues through an innovative biomimetic strategy, introducing an efficient surface nanoengineering approach that creates nano‐geometric features and chemical compositions by modulating the exposure time to a biological medium – Dulbecco's Modified Eagle Medium(DMEM). These nanoengineered Zn implants exhibited tunable degradation rates. The nanostructures enhanced human osteoblast attachment, proliferation, and differentiation following direct contact, and improved macrophage function by promoting pseudopod formation and transitioning from a pro‐inflammatory M1 to a pro‐reparative M2 phenotype. In vivo studies show that the surface‐engineered implants effectively promoted tissue integration via M2 macrophage polarization, resulting in a favorable immunomodulatory environment, and increased collagen deposition. Proteomic analyses show that the tissues in the vicinity of the surface‐engineered Zn implants are enriched with proteins related to key wound healing biological mechanisms such as cell adhesion, cytoskeletal structural arrangement, and immune response. This study highlights the improved biocompatibility and anti‐inflammatory effects of surface‐engineered Zn, with important implications for the clinical translation of biodegradable Zn‐based orthopedic implants.

CRGD-platelet@MnO/MSN@PPARα/LXRα Nanoparticles Improve Atherosclerosis in Rats by Inhibiting Inflammation and Reducing Blood Lipid.

Atherosclerosis (AS) is an inflammatory disease of arterial intima driven by lipids. Liver X receptor alpha (LXRα) and peroxisome proliferator-activated receptor alpha (PPARα) agonists are limited in the treatment of AS due to their off-target effects and serious side effects. Therefore, this study was designed to construct a novel nanoparticle (NP) and evaluate its mechanism of action on inflammation inhibition and lipid reduction in AS. We synthesized cRGD-platelet@MnO/MSN@PPARα/LXRα NPs (cRGD-platelet- NPs) and confirmed their size, safety, and targeting ability through various tests, including dynamic light scattering and immunofluorescence. In vivo and in vitro experiments assessed cell proliferation, apoptosis, inflammation, and plaque formation. Finally, the NF-κB signaling pathway expression in rat aorta was determined using a western blot. The synthesis of cRGD-platelet-NPs was successful; the particle size was approximately 150 nm, and the PDI was below 0.3. They could be successfully absorbed by cells, exhibiting high safety in vivo and in vitro. The cRGD-platelet-NPs successfully reduced plaque formation, improved lipid profiles by lowering LDL-cholesterol, total cholesterol, and triglycerides, and raised HDL-cholesterol levels. Additionally, they decreased inflammatory markers in the serum and aortic tissue, suggesting reduced inflammation. Immunohistochemistry and western blot analyses indicated that these NPs could not only promote M2 macrophage polarization but also suppress the NF-κB signaling pathway. The newly developed cRGD-platelet-NPs with high safety are a promising approach to AS treatment, which can regulate ABCA1, reduce the formation of AS plaques, and enhance cholesterol efflux. The mechanism may involve the suppression of the NF-κB signaling pathway.

FOSL2-mediated transcription of ISG20 induces M2 polarization of macrophages and enhances tumorigenic ability of glioblastoma cells.

Interferon stimulated exonuclease gene 20 (ISG20) has been reported to be correlated with macrophage infiltration in glioblastoma (GBM) in previous bioinformatics-based studies. This study explores the exact effect of ISG20 on macrophage polarization in GBM. ISG20 expression in GBM tissues and cells was determined by RT-qPCR and/or immunohistochemistry. GBM cells were co-cultured with M0 macrophages (PMA-stimulated THP-1 cells) in vitro, followed by flow cytometry and ELISA to analyze the M2 polarization of macrophages. Fluorescence-contained GBM cells were intracranially injected into nude mice along with M0 macrophages to generate orthotopic xenograft tumor models. Upstream regulator of ISG20 was predicted using bioinformatics. Loss- or gain-of-function assays of Fos like 2 (FOSL2) and ISG20 were performed in GBM cells. DNA methylation level of FOSL2 was analyzed by bisulfite sequencing analysis. ISG20 was found highly expressed in GBM tissues and cells. ISG20 silencing in GBM cells decreased CD206 and CD163 levels in the co-cultured macrophages and reduced secretion of IL-10 and TGF-β. It also enhanced survival of nude mice bearing xenograft tumors, blocked tumor growth, and suppressed M2 polarization of macrophages in vivo. FOSL2, highly expressed in GBM, bound to the ISG20 promoter to activate its transcription. FOSL2 silencing similarly blocked M2 polarization of macrophages, which was negated by ISG20 overexpression. The high FOSL2 expression in GBM was attributed to DNA hypomethylation. This study demonstrates that FOSL2 is highly expressed in GBM due to DNA hypomethylation. It activates transcription of ISG20, thus promoting M2 polarization of macrophages and GBM development.