M2-like Macrophage Polarization Research Articles

SHARPIN contributes to sevoflurane-induced neonatal neurotoxicity through up-regulating HMGB1 to repress M2 like-macrophage polarization.

Sevoflurane exposure can result in neurotoxicity especially among children, which remains an important complication after surgery. However, its related mechanisms remain unclear. Here, we investigated the biological roles of SHARPIN in sevoflurane-induced neurotoxicity. As detected by qPCR, Western blotting and immunohistochemical staining, SHARPIN and HMGB1 expression was elevated in sevoflurane-stimulated mice as compared with the control mice. SHARPIN depletion attenuated hippocampus injury, repressed the expression of HMGB1 and M1-like macrophage markers (iNOS, TNF-α, IL-1β, IL-6), but enhanced the expression of M2-like macrophage markers (ARG-1, IL-10). GST pull-down and Co-IP assays demonstrated that SHARPIN directly interacted with HMGB1 to enhance HMGB1 expression in SH-SY5Y cells. The inhibitory effects of SHARPIN silencing on inflammatory reaction and M1-like macrophages were counteracted by HMGB1 overexpression. Finally, SHARPIN-HMGB1 pathway affected neuroinflammation triggered by sevoflurane via modulating macrophage polarization. Collectively, our data suggested that SHARPIN stimulated sevoflurane-induced neurotoxicity via converting M2-like macrophages to M1-like macrophages by enhancing HMGB1 expression. SHARPIN intervention may be a promising therapeutic method to relieve sevoflurane-induced neurotoxicity.

Decoding the complexity of delayed wound healing following Enterococcus faecalis infection

Wound infections are highly prevalent and can lead to delayed or failed healing, causing significant morbidity and adverse economic impacts. These infections occur in various contexts, including diabetic foot ulcers, burns, and surgical sites. Enterococcus faecalis is often found in persistent non-healing wounds, but its contribution to chronic wounds remains understudied. To address this, we employed single-cell RNA sequencing (scRNA-seq) on infected wounds in comparison to uninfected wounds in a mouse model. Examining over 23,000 cells, we created a comprehensive single-cell atlas that captures the cellular and transcriptomic landscape of these wounds. Our analysis revealed unique transcriptional and metabolic alterations in infected wounds, elucidating the distinct molecular changes associated with bacterial infection compared to the normal wound healing process. We identified dysregulated keratinocyte and fibroblast transcriptomes in response to infection, jointly contributing to an anti-inflammatory environment. Notably, E. faecalis infection prompted a premature, incomplete epithelial-mesenchymal transition in keratinocytes. Additionally, E. faecalis infection modulated M2-like macrophage polarization by inhibiting pro-inflammatory resolution in vitro, in vivo, and in our scRNA-seq atlas. Furthermore, we discovered macrophage crosstalk with neutrophils, which regulates chemokine signaling pathways, while promoting anti-inflammatory interactions with endothelial cells. Overall, our findings offer new insights into the immunosuppressive role of E. faecalis in wound infections.

Decoding the complexity of delayed wound healing following Enterococcus faecalis infection.

Wound infections are highly prevalent and can lead to delayed or failed healing, causing significant morbidity and adverse economic impacts. These infections occur in various contexts, including diabetic foot ulcers, burns, and surgical sites. Enterococcus faecalis is often found in persistent non-healing wounds, but its contribution to chronic wounds remains understudied. To address this, we employed single-cell RNA sequencing (scRNA-seq) on infected wounds in comparison to uninfected wounds in a mouse model. Examining over 23,000 cells, we created a comprehensive single-cell atlas that captures the cellular and transcriptomic landscape of these wounds. Our analysis revealed unique transcriptional and metabolic alterations in infected wounds, elucidating the distinct molecular changes associated with bacterial infection compared to the normal wound healing process. We identified dysregulated keratinocyte and fibroblast transcriptomes in response to infection, jointly contributing to an anti-inflammatory environment. Notably, E. faecalis infection prompted a premature, incomplete epithelial-mesenchymal transition in keratinocytes. Additionally, E. faecalis infection modulated M2-like macrophage polarization by inhibiting pro-inflammatory resolution in vitro, in vivo, and in our scRNA-seq atlas. Furthermore, we discovered macrophage crosstalk with neutrophils, which regulates chemokine signaling pathways, while promoting anti-inflammatory interactions with endothelial cells. Overall, our findings offer new insights into the immunosuppressive role of E. faecalis in wound infections.

Mechanical stretch preconditioned adipose-derived stem cells elicit polarization of anti-inflammatory M2-like macrophages and improve chronic wound healing.

Transplantation of adipose-derived stem cells (ASCs) is a promising option in the field of chronic wounds treatment. However, the effectiveness of ASCs therapies has been hampered by highly inflammatory environment in chronic wound areas. These problems could be partially circumvented using efficient approaches that boost the survival and anti-inflammatory capacity of transplanted ASCs. Here, by application of mechanical stretch (MS), we show that ASCs exhibits increased survival and immunoregulatory properties invitro. MS triggers the secretion of macrophage colony stimulating factor (M-CSF) from ASCs, a chemokine that is linked to anti-inflammatory M2-like macrophages polarization. When the MS-ASCs were transplanted to chronic wounds, the wound area yields significantly faster closure rate and lower inflammatory mediators, largely due to macrophages polarization driven by transplanted MS-ASCs. Thus, our work shows that mechanical stretch can be harnessed to enhance ASCs transplantation efficiency in chronic wounds treatment.

Abstract 5368: Targeting tumor-intrinsic S100A1 augments antitumour immunity and potentiates anti-PD-1 efficacy

Abstract Immune-checkpoint blockade (ICB) has revolutionized cancer treatment. However, only a minority of patients achieve the long-term, durable response to ICB, and the response rates in most advanced tumors is limited to 10%-25%. The unsatisfactory overall response to ICB and the great variation in response among individuals highlight the necessity for developing predictive biomarkers and overcoming ICB resistance. A potential mode of resistance is tumor-mediated immunosuppression leading to inhibition of T cell-mediated infiltration and immunity. Here, combining single-cell and bulk transcriptomic analysis with liquid biopsy of tumor patients, we showed that S100 calcium binding protein A1 (S100A1) was closely related to ICB response, and that detecting plasma S100A1 level could help predicting the response to ICB, implying that tumor-intrinsic S100A1 may contribute to immunosuppressive tumor microenvironment (TME) and resistance to ICB. Importantly, endogenous S100a1 knockdown (S100a1KD) promoted anti-tumor immunity, conferred tumor regression, and sensitized tumors to anti-PD-1 immunotherapy in multiple syngeneic murine models. By characterizing the immune landscape of S100a1KD syngeneic murine tumor models and non-small cell lung cancer (NSCLC) clinical samples, we demonstrated a negative relationship between tumor-intrinsic S100A1 expression and infiltration of M1-like macrophage and CD8+ T cells. Single cell and spatial transcriptomic analyses, together with functional studies, have revealed that ablation of tumor-intrinsic S100A1 exerts profound impacts on the M1-like polarization of macrophages and cytotoxicity of CD8+ T cells. Moreover, the conditioned medium from S100a1KD tumor cells promoted M1 polarization of both bone marrow-derived macrophages (BMDMs) and Raw264.7 cells, which in turn reinvigorated tumor-specific T cell immunity both in vitro and in vivo. Of note, as a secreted protein, introducing recombinant S100A1 into the medium from S100a1KD tumor cells could not reverse the effects on T cells and macrophages, suggesting that these effects were independent of extracelluar S100A1 secretion and that S100A1 may act as an intracellular signaling molecule. Mechanistically, S100A1 affects deubiquitination of NF-κB through interacting with the ubiquitin-like (Ubl) domains of ubiquitin specific protease 7 (USP7), leading to upregulated granulocyte-macrophage colony-stimulating factor (GM-CSF) expression. Collectively, these data identified the S100A1/USP7/p65/GM-CSF inhibitory axis as a critical immune suppressor on M1-like macrophage polarization and T cell immunity for the promotion of tumor progression and resistance to ICB. Our findings demonstrated the potential of plasma S100A1 expression in predicting the response to ICB, and provide a rationale for combining GM-CSF and anti-PD-1 immunotherapy in tumors with high S100A1 expression. Citation Format: Yufeng Guo, Hua Bai, Jie Wang. Targeting tumor-intrinsic S100A1 augments antitumour immunity and potentiates anti-PD-1 efficacy [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 5368.

Abstract 3843: Role of CD4/CD8 double positive T cells in modulating response to anti-PD-1 treatment in renal cell carcinoma

Abstract Presence of CD4+CD8+ Double Positive T (DPT) cells in the tumor microenvironment has been correlated with good prognosis1. Renal cell carcinoma (RCC) is reported to have relatively much higher DPT cell sub-populations as compared to other cancer types1,2. DPT cells in RCC were reported to express high programmed cell death protein-1(PD-1) and therefore is considered a potential target for checkpoint based immunotherapy2. However, the clinical relevance of these DPT cells in determining response to anti-PD-1 has not yet been studied. Using the near native FarcastTM TruTumor RCC histoculture platform, we attempted to elucidate the role of DPT in anti-PD1 response modulation. Fresh surgically resected RCC samples (n=18) along with matched blood were collected from consented patients. Explants were generated and distributed into arms. These arms were treated in culture with nivolumab (anti-PD1:132µg/ml) for 72 hours. The response was evaluated using histopathology and flow cytometry read-outs. DPT cells were gated and expressed as percentage of CD3 using flowcytometry. We observed a significantly higher proportion of DPT cells in RCC (Mean±SEM: 8.2±2.8) compared to head and neck squamous cell carcinoma (Mean±SEM: 1.2±0.4) and ovarian cancer (Mean±SEM: 0.7±0.1). DPT cell population was found to be well preserved on the TruTumor RCC platform post-culture. We stratified samples as high and low DPT cell sub cohorts based on 5% cut-off. Out of 18, 6 samples (33%) showed high DPT cells (with a range of 7-41%). Eighty-three percent (5 out of 6) of high DPT samples elicited a tumor cytotoxicity on treatment with Nivolumab treatment as compared to only 50% (6 out of 12) in low DPT samples. A significant decrease (p<0.05) in DPT cells was observed in the high DPT sub cohort upon Nivolumab treatment, with a concomitant increase in activated (Granzyme B+) DPT and cytotoxic T cells (CD8+) sub-populations was observed upon nivolumab treatment. However, total CD8+ proportions remained unchanged. In addition, an increase in effector (CD4+ FoxP3-) and decrease in Treg (CD4+FoxP3+) population was also observed. Only one out of six high DPT samples exhibited no cytotoxicity in response to nivolumab treatment. Interestingly in this non-responder sample there was a 3.1-fold increase in M2-like (CD68+CD206+) macrophages, as compared to a M1-like macrophage polarization observed in the remaining high DPT samples. In summary, our data suggests that presence of high percentage of DPT cells could favour better response to anti-PD1 therapy in RCC patients. The FarcastTM TruTumor platform thus provides powerful insights into the role of various immune cell sub-populations in modulating response to treatment with immune-oncology therapies.

Unveiling CXCR2 as a promising therapeutic target in renal cell carcinoma: exploring the immunotherapeutic paradigm shift through its inhibition by RCT001

BackgroundIn clear cell renal cell carcinoma (ccRCC), first-line treatment combines nivolumab (anti-PD-1) and ipilimumab (anti-CTLA4), yielding long-term remissions but with only a 40% success rate. Our study explored the potential of enhancing ccRCC treatment by concurrently using CXCR2 inhibitors alongside immunotherapies.MethodsWe analyzed ELR + CXCL levels and their correlation with patient survival during immunotherapy. RCT001, a unique CXCR2 inhibitor, was examined for its mechanism of action, particularly its effects on human primary macrophages. We tested the synergistic impact of RCT001 in combination with immunotherapies in both mouse models of ccRCC and human ccRCC in the presence of human PBMC.ResutsElevated ELR + CXCL cytokine levels were found to correlate with reduced overall survival during immunotherapy. RCT001, our optimized compound, acted as an inverse agonist, effectively inhibiting angiogenesis and reducing viability of primary ccRCC cells. It redirected M2-like macrophages without affecting M1-like macrophage polarization directed against the tumor. In mouse models, RCT001 enhanced the efficacy of anti-CTLA4 + anti-PD1 by inhibiting tumor-associated M2 macrophages and tumor-associated neutrophils. It also impacted the activation of CD4 T lymphocytes, reducing immune-tolerant lymphocytes while increasing activated natural killer and dendritic cells. Similar effectiveness was observed in human RCC tumors when RCT001 was combined with anti-PD-1 treatment.ConclusionsRCT001, by inhibiting CXCR2 through its unique mechanism, effectively suppresses ccRCC cell proliferation, angiogenesis, and M2 macrophage polarization. This optimization potentiates the efficacy of immunotherapy and holds promise for significantly improving the survival prospects of metastatic ccRCC patients.

LncRNAs act as modulators of macrophages within the tumor microenvironment.

Long non-coding RNAs (lncRNAs) have been established as pivotal players in various cellular processes, encompassing the regulation of transcription, translation, post-translational modulation of proteins, thereby influencing cellular functions. Notably, lncRNAs exert a regulatory influence on diverse biological processes, particularly in the context of tumor development. Tumor-associated macrophages (TAMs) exhibit the M2 phenotype, exerting significant impact on crucial processes such as tumor initiation, angiogenesis, metastasis, and immune evasion. Elevated infiltration of TAMs into the tumor microenvironment (TME) is closely associated with a poor prognosis in various cancers. LncRNAs within TAMs play a direct role in regulating cellular processes. Functioning as integral components of tumor-derived exosomes, lncRNAs prompt the M2-like polarization of macrophages. Concurrently, reports indicate that lncRNAs in tumor cells contribute to the expression and release of molecules that modulate TAMs within the TME. These actions of lncRNAs induce the recruitment, infiltration, and M2 polarization of TAMs, thereby providing critical support for tumor development. In this review, we survey recent studies elucidating the impact of lncRNAs on macrophage recruitment, polarization, and function across different types of cancers.

Abstract A081: Chromobox 2 (CBX2) drives an immunosuppressive tumor microenvironment in high grade serous carcinoma (HGSC)

Abstract Introduction: Epigenetic reader and component of Polycomb Repressor Complex 1 (PRC1), Chromobox 2 (CBX2) is expressed in greater than 75% of high-grade serous carcinoma (HGSC) tumors. Increased CBX2 expression conveys a poorer disease-free and overall survival. CBX2 knockdown leads to increased chemotherapy sensitivity and attenuates stem-like properties, while CBX2 overexpression is sufficient to promote chemoresistance. In an HGSC immune competent murine model, knockdown of CBX2 decreased tumor progression. We sought to explore the impact of modulation of CBX2 on the tumor immune microenvironment (TIME), understanding that TIME plays a critical role in disease progression and development of therapy resistance. Methods: We performed an exploration of existing data sets, including The Cancer Genome Atlas (TCGA), TIMERv2, and Carcinoma EcoTyper. We used HGSC cell lines (OVCAR4 and PEO1) with knockdown of CBX2 and RNA-sequencing. KEGG pathway analysis performed. A syngeneic ID8 mouse model was completed with shCBX2 compared to shControl. Nanostring Immuno-Oncology Panel and Multispectral Immunohistochemistry (mIHC) were completed to evaluate the TIME. Cell lines with genetic CBX2 modulation were utilized to create spheroids to recapitulate HGSC growth and confocal microscopy was employed to evaluate macrophage recruitment. Monocyte recruitment and macrophage polarization were evaluated using flow cytometry. Results: We found that existing data sets demonstrate a shift in TIME dependent on up or downregulation of CBX2. For instance, high CBX2 is associated with decreased CD8+ T cells (14.69% vs. 4.89%, p=0.0032) and increased undifferentiated macrophages (14.77 vs. 29.93%, p=0.006). Also, CBX2 is a defining feature of the Cell State Type 6 Carcinoma EcoType, which is associated with poor prognosis. RNA sequencing identified an association between CBX2 and CCL2, a cytokine known to recruit immunosuppressive macrophages. Pathway analysis of differentially expressed genes demonstrates an enrichment of several immune signatures. CBX2 knockdown in the ID8 syngeneic mouse model led to decreased tumor progression compared to control (11.50 mg. vs 51.63 mg, p=0.0001). NanoString analysis of the specimens suggest a shift in immune cell composition, with an increase in macrophages. mIHC defined the spatial relationships in this composition and confirmed increase in macrophage infiltration (28.64% vs. 34.60%, p=0.0231). Confocal microscopy and co-culture experiments to explore monocyte recruitment, found that both knockdown and overexpression of CBX2 lead to increased recruitment and infiltration of macrophages. Flow cytometry of macrophages cultured with CBX2 overexpressing cells showed an increase in M2-like (CD206+) macrophages and decreased phagocytosis activity. Conclusion: Increased CBX2 expression leads to increased recruitment and polarization of M2-like macrophages leading to an immunosuppressive TIME. Targeting of CBX2 may serve to modulate the TIME to enhance the efficacy of immune therapies. Citation Format: Lindsay W. Brubaker, Ritsuko Iwanaga, Tomomi M Yamamoto, Elizabeth R. Woodruff, Nicole Marjon, Siddhartha Mitra, Benjamin G. Bitler. Chromobox 2 (CBX2) drives an immunosuppressive tumor microenvironment in high grade serous carcinoma (HGSC) [abstract]. In: Proceedings of the AACR Special Conference on Ovarian Cancer; 2023 Oct 5-7; Boston, Massachusetts. Philadelphia (PA): AACR; Cancer Res 2024;84(5 Suppl_2):Abstract nr A081.

An NFAT1-C3a-C3aR Positive Feedback Loop in Tumor-Associated Macrophages Promotes a Glioma Stem Cell Malignant Phenotype.

Extensive infiltration by tumor-associated macrophages (TAM) in combination with myeloid-derived suppressor cells constitute the immunosuppressive microenvironment and promote the malignant phenotype of gliomas. The aggressive mesenchymal (MES)-subtype glioma stem cells (GSC) are prominent in the immunosuppressive microenvironment of gliomas. However, the underlying immune-suppressive mechanisms are still unknown. The current study showed that the antitumor immune microenvironment was activated in glioma in Nfat1-/- mice, suggesting induction of the immune-suppressive microenvironment by nuclear factor of activated T cells-1 (NFAT1). In TAMs, NFAT1 could upregulate the transcriptional activity of complement 3 (C3) and increase the secretion of C3a, which could then bind to C3aR and promote M2-like macrophage polarization by activating TIM-3. Simultaneously, C3a/C3aR activated the Ca2+-NFAT1 pathway, forming a positive feedback loop for the M2-like polarization of TAMs, which further promoted the MES transition of GSCs. Finally, disruption of this feedback loop using a C3aR inhibitor significantly inhibited glioma growth both in vitro and in vivo. The current study demonstrated that a NFAT1-C3a-C3aR positive feedback loop induces M2-like TAMs and further promotes the malignant phenotype of GSCs, which might be the potential therapeutic target for glioma.

LncRNA MEG3 Reduces the Ratio of M2/M1 Macrophages Through the HuR/CCL5 Axis in Hepatocellular Carcinoma.

Tumor-associated macrophages play a crucial role in the development of hepatocellular carcinoma (HCC). Our study aimed to investigate the relationship between long coding RNA (lncRNA) maternally expressed gene 3 (MEG3), RNA-binding protein human antigen R (HuR), and messenger RNA C-C motif chemokine 5 (CCL5) in the modulation of M1 and M2 macrophage polarization in HCC. To induce M1 or M2 polarization, LPS/IFNγ- or IL4/IL13 were used to treat bone marrow derived macrophages (BMDMs). The localization of MEG3 in M1 and M2 macrophages was assessed using fluorescence in situ hybridization assay. Expression levels of MEG3, HuR, CCL5, M1, and M2 markers were measured by RT-qPCR or immunofluorescence staining. Flow cytometry was performed to determine the proportion of F4/80+CD206+ and F4/80+CD68+ cells. RNA pulldown assay was performed to detect the binding of lncRNA MEG3 and HuR. The impacts of HuR on CCL5 stability and activity of CCL5 promoter were evaluated using actinomycin D treatment and luciferase reporter assay. Cell migration, invasiveness, and angiogenesis were assessed using transwell migration and invasion assays and a tube formation assay. A mixture of Huh-7 cells and macrophages were injected into nude mice to explore the effect of MEG3 on tumorigenesis. MEG3 promoted M1-like polarization while dampening M2-like polarization of BMDMs. MEG3 bound to HuR in M1 and M2 macrophages. HuR downregulated CCL5 by inhibiting CCL5 transcription in macrophages. In addition, overexpression of MEG3 suppressed cell metastasis, invasion, and angiogenesis by obstructing macrophage M2 polarization. MEG3 inhibited tumorigenesis in HCC via promotion of M1-like polarization and inhibition of M2-like polarization. Rescue experiments showed that depletion of CCL5 in M2 macrophages reversed MEG3-induced suppressive effect on cell migration, invasion, and tube formation. MEG3 suppresses HCC progression by promoting M1-like while inhibiting M2-like macrophage polarization via binding to HuR and thus upregulating CCL5.

Inactivation of pentraxin 3 suppresses M2-like macrophage activity and immunosuppression in colon cancer

BackgroundThe tumor microenvironment is characterized by inflammation-like and immunosuppression situations. Although cancer-associated fibroblasts (CAFs) are among the major stromal cell types in various solid cancers, including colon cancer, the interactions between CAFs and immune cells remains largely uncharacterized. Pentraxin 3 (PTX3) is responsive to proinflammatory cytokines and modulates immunity and tissue remodeling, but its involvement in tumor progression appears to be context-dependent and is unclear.MethodsOpen-access databases were utilized to examine the association of PTX3 expression and the fibroblast signature in colon cancer. Loss-of-function assays, including studies in tamoxifen-induced Ptx3 knockout mice and treatment with an anti-PTX3 neutralizing antibody (WHC-001), were conducted to assess the involvement of PTX3 in colon cancer progression as well as its immunosuppressive effect. Finally, bioinformatic analyses and in vitro assays were performed to reveal the downstream effectors and decipher the involvement of the CREB1/CEBPB axis in response to PTX3 and PTX3-induced promotion of M2 macrophage polarization.ResultsClinically, higher PTX3 expression was positively correlated with fibroblasts and inflammatory response signatures and associated with a poor survival outcome in colon cancer patients. Blockade of PTX3 significantly reduced stromal cell-mediated tumor development. The decrease of the M2 macrophage population and an increase of the cytotoxic CD8+ T-cell population were observed following PTX3 inactivation in allografted colon tumors. We further revealed that activation of cyclic AMP-responsive element-binding protein 1 (CREB1) mediated the PTX3-induced promotion of M2 macrophage polarization.ConclusionsPTX3 contributes to stromal cell-mediated protumor immunity by increasing M2-like macrophage polarization, and inhibition of PTX3 with WHC-001 is a potential therapeutic strategy for colon cancer.

IL4I1 in M2-like macrophage promotes glioma progression and is a promising target for immunotherapy.

Glioma is the prevailing malignant intracranial tumor, characterized by an abundance of macrophages. Specifically, the infiltrating macrophages often display the M2 subtype and are known as tumor-associated macrophages (TAMs). They have a critical role in promoting the oncogenic properties of tumor cells. Interleukin-4-induced-1 (IL4I1) functions as an L-phenylalanine oxidase, playing a key part in regulating immune responses and the progression of various tumors. However, there is limited understanding of the IL4I1-mediated cross-talk function between TAMs and glioma cell in the glioma microenvironment. TCGA, GTEx, and HPA databases were applied to assess the IL4I1 expression, clinical characteristics, and prognostic value of pan-cancer. The link between IL4I1 levels and the prognosis, methylation, and immune checkpoints (ICs) in gliomas were explored through Kaplan-Meier curve, Cox regression, and Spearman correlation analyses. The IL4I1 levels and their distribution were investigated by single-cell analysis and the TIMER 2 database. Additionally, validation of IL4I1 expression was performed by WB, RT-qPCR, IHC, and IF. Co-culture models between glioma cells and M2-like macrophages were used to explore the IL4I1-mediated effects on tumor growth, invasion, and migration of glioma cells. Moreover, the function of IL4I1 on macrophage polarization was evaluated by ELISA, RT-qPCR, WB, and siRNA transfection. Both transcriptome and protein levels of IL4I1 were increased obviously in various tumor types, and correlated with a dismal prognosis. Specifically, IL4I1 was implicated in aggressive progression and a dismal prognosis for patients with glioma. A negative association was noticed between the glioma grade and DNA promoter methylation of IL4I1. Enrichment analyses in glioma patients suggested that IL4I1 was linked to cytokine and immune responses, and was positively correlated with ICs. Single-cell analysis, molecular experiments, and in vitro assays showed that IL4I1 was significantly expressed in TAMs. Importantly, co-culture models proved that IL4I1 significantly promoted the invasion and migration of glioma cells, and induced the polarization of M2-like macrophages. IL4I1 could be a promising immunotherapy target for selective modulation of TAMs and stands as a novel macrophage-related prognostic biomarker in glioma.

Exploring the Therapeutic Potential of Ampelopsis grossedentata Leaf Extract as an Anti-Inflammatory and Antioxidant Agent in Human Immune Cells.

Inflammation is a vital protective response to threats, but it can turn harmful if chronic and uncontrolled. Key elements involve pro-inflammatory cells and signaling pathways, including the secretion of pro-inflammatory cytokines, NF-κB, reactive oxygen species (ROS) production, and the activation of the NLRP3 inflammasome. Ampelopsis grossedentata, or vine tea, contains dihydromyricetin (DHM) and myricetin, which are known for their various health benefits, including anti-inflammatory properties. Therefore, the aim of this study is to assess the impact of an extract of A. grossedentata leaves (50 µg/mL) on inflammation factors such as inflammasome, pro-inflammatory pathways, and macrophage polarization, as well as its antioxidant properties, with a view to combating the development of low-grade inflammation. Ampelopsis grossedentata extract (APG) significantly decreased ROS production and the secretion of pro-inflammatory cytokines (IFNγ, IL-12, IL-2, and IL-17a) in human leukocytes. In addition, APG reduced LPS/IFNγ -induced M1-like macrophage polarization, resulting in a significant decrease in the expression of the pro-inflammatory cytokines TNF-α and IL-6, along with a decrease in the percentage of M1 macrophages and an increase in M0 macrophages. Simultaneously, a significant decrease in NF-κB p65 phosphorylation and in the expression of inflammasome genes (NLRP3, IL-1β and Caspase 1) was observed. The results suggest that Ampelopsis grossedentata could be a promising option for managing inflammation-related chronic diseases. Further research is needed to optimize dosage and administration methods.

A novel AluYb8 insertion-associated non-coding RNA, lncMUTYH, impairs mitochondrial function and dampens the M2-like polarization of macrophages

An inverted AluYb8 insertion in the MUTYH intron 15 (AluYb8MUTYH variant) has been reported to be associated with reduced MUTYH1 expression and mitochondrial dysfunction with age. However, the underlying mechanism remains unknown. In this study, we identified a novel transcript associated with the AluYb8MUTYH variant, which revealed that this transcript is about 780 nucleotides in length with a poly-A tail, lacks protein-coding potential, referred to as lncMUTYH. The results from the reporter gene system confirmed that the lncMUTYH down-regulates MUTYH1 expression at the translational level. Site-directed mutagenesis on the 5′-terminal exon sequences of α-MUTYH and lncMUTYH constructs revealed that lncMUTYH can act as a trans-regulator that depends on the partial base pairing between its exonized AluYb8 sequence and the 5′UTR of α-MUTYH to impede MUTYH 1 expression. Furthermore, we have demonstrated a correlation between decreased mitochondrion-localized MUTYH1 caused by lncMUTYH and lowered levels of mitochondrial biological function indicators, such as mtDNA content, mitochondrial regulatory gene expression, oxygen consumption rate, ATP product, and mitochondrial respiratory capacity. Notably, we found that lncMUTYH inhibited the M2-like polarization of macrophages, and CD68/CD206-positive cell fractions were significantly lower in lncMUTYH ectopically expressing cells. The results confirmed that the AluYb8MUTYH-associated lncMUTYH, derived from an AluYb8 insertion mutation, acts as a trans-regulatory factor that inhibits the MUTYH1 protein expression, leading to a progressive mitochondrial dysfunction that may disrupt macrophage differentiation. In summary, lncMUTYH can contribute to AluYb8MUTYH-associated mitochondrial dysfunction with age and hamper the macrophage polarization process, potentially increasing the risk of developing age-related diseases.

GABA induced by sleep deprivation promotes the proliferation and migration of colon tumors through miR-223-3p endogenous pathway and exosome pathway

BackgroundResearch has indicated that long-term sleep deprivation can lead to immune dysfunction and participate in the occurance and progression of tumors. However, the relationship between sleep deprivation and colon cancer remains unclear. This study explored the specific mechanism through which sleep deprivation promotes the proliferation and migration of colon cancer, with a focus on the neurotransmitter GABA.MethodsChronic sleep deprivation mice model were used to investigate the effect of sleep disorder on tumors. We detected neurotransmitter levels in the peripheral blood of mice using ELISA. CCK-8 assay, colony formation assay, wound healing assay, and transwell assay were performed to investigate the effect of GABA on colon cancer cells, while immunofluorescence showed the distribution of macrophages in lung metastatic tissues. We isolated exosomes from a GABA-induced culture medium to explore the effects of GABA-induced colon cancer cells on macrophages. Gain- and loss-of-function experiments, luciferase report analysis, immunohistochemistry, and cytokine detection were performed to reveal the crosstalk between colon cancer cells and macrophages.ResultsSleep deprivation promote peripheral blood GABA level and colon cancer cell proliferation and migration. Immunofluorescence analysis revealed that GABA-induced colon cancer metastasis is associated with enhanced recruitment of macrophages in the lungs. The co-culture results showed that GABA intensified M2 polarization of macrophage induced by colon cancer cells. This effect is due to the activation of the macrophage MAPK pathway by tumor-derived exosomal miR-223-3p. Furthermore, M2-like macrophages promote tumor proliferation and migration by secreting IL-17. We also identified an endogenous miR-223-3p downregulation of the E3 ligase CBLB, which enhances the stability of cMYC protein and augments colon cancer cells proliferation and migration ability. Notably, cMYC acts as a transcription factor and can also regulate the expression of miR-223-3p.ConclusionOur results suggest that sleep deprivation can promote the expression of miR-223-3p in colon cancer cells through GABA, leading to downregulation of the E3 ligase CBLB and inhibition of cMYC ubiquitination. Simultaneously, extracellular miR-223-3p promotes M2-like macrophage polarization, which leads to the secretion of IL-17, further enhancing the proliferation and migration of colon cancer cells.

Fever-Range Hyperthermia Promotes Macrophage Polarization towards Regulatory Phenotype M2b.

Fever-range hyperthermia (FRH) is utilized in chronic disease treatment and serves as a model for fever's thermal component investigation. Macrophages, highly susceptible to heat, play a pivotal role in various functions determined by their polarization state. However, it is not well recognized whether this process can be modulated by FRH. To address this, we used two different macrophage cell lines that were treated with FRH. Next, to define macrophage phenotype, we examined their functional surface markers CD80 and CD163, intracellular markers such as inducible nitric oxide synthase (iNOS), arginase-1 (Arg-1), and the expression of interleukin-10 (IL-10) and tumor necrosis factor α (TNF-α). Additionally, in FRH-treated cells, we analyzed an expression of Toll-like receptor 4 (TLR-4) and its role in macrophage polarization. We also checked whether FRH can switch the polarization of macrophages in pro-inflammatory condition triggered by lipopolysaccharide (LPS). FRH induced M2-like polarization, evident in increased CD163, IL-10, and Arg-1 expression. Notably, elevated COX-2, TNF-α, and TLR-4 indicated potential pro-inflammatory properties, suggesting polarization towards the M2b phenotype. Additionally, FRH shifted lipopolysaccharide (LPS)-induced M1 polarization to an M2-like phenotype, reducing antimicrobial molecules (ROS and NO). In summary, FRH emerged as a modulator favoring M2-like macrophage polarization, even under pro-inflammatory conditions, showcasing its potential therapeutic relevance.

Local Spinal Cord Injury Treatment Using a Dental Pulp Stem Cell Encapsulated H2S Releasing Multifunctional Injectable Hydrogel.

Spinal cord injury (SCI) commonly induces nerve damage and nerve cell degeneration. In this work, a novel dental pulp stem cells (DPSCs) encapsulated thermoresponsive injectable hydrogel with sustained hydrogen sulfide (H2S) delivery is demonstrated for SCI repair. For controlled and sustained H2S gas therapy, a clinically tested H2S donor (JK) loaded octysilane functionalized mesoporous silica nanoparticles (OMSNs) are incorporated into the thermosensitive hydrogel made from Pluronic F127 (PF-127). The JK-loaded functionalized MSNs (OMSF@JK) promote preferential M2-like polarization of macrophages and neuronal differentiation of DPSCs in vitro. OMSF@JK incorporated PF-127 injectable hydrogel (PF-OMSF@JK) has a soft consistency similar to that of the human spinal cord and thus, shows a high cytocompatibility with DPSCs. The cross-sectional micromorphology of the hydrogel shows a continuous porous structure. Last, the PF-OMSF@JK composite hydrogel considerably improves the in vivo SCI regeneration in Sprague-Dawley rats through a reduction in inflammation and neuronal differentiation of the incorporated stem cells as confirmed using western blotting and immunohistochemistry. The highly encouraging in vivo results prove that this novel design on hydrogel is a promising therapy for SCI regeneration with the potential for clinical translation.

SNHG17 alters anaerobic glycolysis by resetting phosphorylation modification of PGK1 to foster pro-tumor macrophage formation in pancreatic ductal adenocarcinoma

BackgroundWithin the tumor immune microenvironment (TME), tumor-associated macrophages (TAMs) are crucial in modulating polarization states to influence cancer development through metabolic reprogramming. While long non-coding RNAs (lncRNAs) have been shown to play a pivotal role in the progression of various cancers, the underlying mechanisms by which lncRNAs alter M2 polarization through macrophage metabolism remodeling remain unelucidated.MethodsRNA sequencing was used to screen for differentially expressed lncRNAs in TAMs and normal tissue-resident macrophages (NTRMs) isolated from pancreatic ductal adenocarcinoma (PDAC) tissues, whilst RT-qPCR and FISH were employed to detect the expression level of SNHG17. Moreover, a series of in vivo and in vitro experiments were conducted to assess the functions of SNHG17 from TAMs in the polarization and glycolysis of M2-like macrophages and in the proliferation and metastasis of pancreatic cancer cells (PCs). Furthermore, Western blotting, RNA pull-down, mass spectrometry, RIP, and dual-luciferase assays were utilized to explore the underlying mechanism through which SNHG17 induces pro-tumor macrophage formation.ResultsSNHG17 was substantially enriched in TAMs and was positively correlated with a worse prognosis in PDAC. Meanwhile, functional assays determined that SNHG17 promoted the malignant progression of PCs by enhancing M2 macrophage polarization and anaerobic glycolysis. Mechanistically, SNHG17 could sponge miR-628-5p to release PGK1 mRNA and concurrently interact with the PGK1 protein, activating the pro-tumorigenic function of PGK1 by enhancing phosphorylation at the T168A site of PGK1 through ERK1/2 recruitment. Lastly, SNHG17 knockdown could reverse the polarization status of macrophages in PDAC.ConclusionsThe present study illustrated the essential role of SNHG17 and its molecular mechanism in TAMs derived from PDAC, indicating that SNHG17 might be a viable target for PDAC immunotherapy.

CD133-containing microvesicles promote cancer progression by inducing M2-like tumor-associated macrophage polarization in the tumor microenvironment of colorectal cancer.

Tumor-associated macrophages (TAMs) are among the most abundant cell types in the tumor microenvironment (TME). The immunosuppressive TME formed by TAMs is an essential prerequisite for cancer progression. Tumor-derived microvesicles (MVs), a subtype of extracellular vesicle shed directly from the plasma membrane, are important regulators of intercellular communication and TME modulation during tumorigenesis. However, the exact mechanism by which tumor-derived MVs induce the generation of the immunosuppressive TME and polarization of TAMs remains unclear. Here, we investigated the role of CD133-containing MVs derived from colorectal cancer (CRC) cells in macrophage polarization and cancer progression. CD133-containing MVs from CRC cells were incorporated into macrophages, and M0 macrophages were morphologically transformed into M2-like TAMs. CD133-containing MVs were found to increase the mRNA expression of M2 macrophage markers. Additionally, cytokine array analysis revealed that M2-like TAMs induced by CD133-containing MVs increased the secretion of interleukin 6, which activated the STAT3 pathway in CRC cells. Furthermore, the conditioned medium of M2-like TAMs promoted cell motility, epithelial-mesenchymal transition, and cell proliferation. However, MVs from CD133-knockdown cells had little effect on TAM polarization and CRC progression. These results demonstrate that CD133-containing MVs induce M2-like TAM polarization and contribute to cancer progression by mediating crosstalk between tumor cells and TAMs in the TME of CRC.