Exosomes derived from vMIP-II-Lamp2b gene-modified M2 cells provide neuroprotection by targeting the injured spinal cord, inhibiting chemokine signals and modulating microglia/macrophage polarization in mice

Inflammation is one of the key injury factors for spinal cord injury (SCI). Exosomes (Exos) derived from M2 macrophages have been shown to inhibit inflammation and be beneficial in SCI animal models. However, lacking targetability restricts their application prospects. Considering that chemokine receptors increase dramatically after SCI, viral macrophage inflammatory protein II (vMIP-II) is a broad-spectrum chemokine receptor binding peptide, and lysosomal associated membrane protein 2b (Lamp2b) is the key membrane component of Exos, we speculated that vMIP-II-Lamp2b gene-modified M2 macrophage-derived Exos (vMIP-II-Lamp2b-M2-Exo) not only have anti-inflammatory properties, but also can target the injured area by vMIP-II. In this study, using a murine contusive SCI model, we revealed that vMIP-II-Lamp2b-M2-Exo could target the chemokine receptors which highly expressed in the injured spinal cords, inhibit some key chemokine receptor signaling pathways (such as MAPK and Akt), further inhibit proinflammatory factors (such as IL-1β, IL-6, IL-17, IL-18, TNF-α, and iNOS), and promote anti-inflammatory factors (such as IL-4 and Arg1) productions, and the transformation of microglia/macrophages from M1 into M2. Moreover, the improved histological and functional recoveries were also found. Collectively, our results suggest that vMIP-II-Lamp2b-M2-Exo may provide neuroprotection by targeting the injured spinal cord, inhibiting some chemokine signals, reducing proinflammatory factor production and modulating microglia/macrophage polarization.

Rejuvenating fecal microbiota transplant enhances peripheral nerve repair in aged mice by modulating endoneurial inflammation

Peripheral nerve injury (PNI) resulting from trauma or neuropathies can cause significant disability, and its prognosis deteriorates with age. Emerging evidence suggests that gut dysbiosis and reduced fecal short-chain fatty acids (SCFAs) contribute to an age-related systemic hyperinflammation (inflammaging), which hinders nerve recovery after injury. This study thus aimed to evaluate the pro-regenerative effects of a rejuvenating fecal microbiota transplant (FMT) in a preclinical PNI model using aged mice. Aged C57BL/6 mice underwent bilateral crush injuries to their sciatic nerves. Subsequently, they either received FMT from young donors at three and four days after the injury or retained their aged gut microbiota. We analyzed gut microbiome composition and SCFA concentrations in fecal samples. The integrity of the ileac mucosal barrier was assessed by immunofluorescence staining of Claudin-1. Flow cytometry was utilized to examine immune cells and cytokine production in the ileum, spleen, and sciatic nerve. Various assessments, including behavioural tests, electrophysiological studies, and morphometrical analyses, were conducted to evaluate peripheral nerve function and repair following injury. Rejuvenating FMT reversed age-related gut dysbiosis by increasing Actinobacteria, especially Bifidobacteriales genera. This intervention also led to an elevation of gut SCFA levels and mitigated age-related ileac mucosal leakiness in aged recipients. Additionally, it augmented the number of T-helper 2 (Th2) and regulatory T (Treg) cells in the ileum and spleen, with the majority being positive for anti-inflammatory interleukin-10 (IL-10). In sciatic nerves, rejuvenating FMT resulted in increased M2 macrophage counts and a higher IL-10 production by IL-10+TNF-α- M2 macrophage subsets. Ultimately, restoring a youthful gut microbiome in aged mice led to improved nerve repair and enhanced functional recovery after PNI. Considering that FMT is already a clinically available technique, exploring novel translational strategies targeting the gut microbiome to enhance nerve repair in the elderly seems promising and warrants further evaluation.

Paediatric sepsis survivors are resistant to sepsis-induced long-term immune dysfunction

BACKGROUND AND PURPOSE

Sepsis-surviving adult individuals commonly develop immunosuppression and increased susceptibility to secondary infections, an outcome mediated by the axis IL-33/ILC2s/M2 macrophages/Tregs. Nonetheless, the long-term immune consequences of paediatric sepsis are indeterminate. We sought to investigate the role of age in the genesis of immunosuppression following sepsis.

EXPERIMENTAL APPROACH

Here, we compared the frequency of Tregs, the activation of the IL-33/ILC2s axis in M2 macrophages and the DNA methylation of epithelial lung cells from post-septic infant and adult mice. Likewise, sepsis-surviving mice were inoculated intranasally with Pseudomonas aeruginosa or by subcutaneous inoculation of the B16 melanoma cell line. Finally, blood samples from sepsis-surviving patients were collected and the concentration of IL-33 and Tregs frequency were assessed.

KEY RESULTS

In contrast to 6-week-old mice, 2-week-old mice were resistant to secondary infection and did not show impairment in tumour controls upon melanoma challenge. Mechanistically, increased IL-33 levels, Tregs expansion, and activation of ILC2s and M2-macrophages were observed in 6-week-old but not 2-week-old post-septic mice. Moreover, impaired IL-33 production in 2-week-old post-septic mice was associated with increased DNA methylation in lung epithelial cells. Notably, IL-33 treatment boosted the expansion of Tregs and induced immunosuppression in 2-week-old mice. Clinically, adults but not paediatric post-septic patients exhibited higher counts of Tregs and seral IL-33 levels.

CONCLUSION AND IMPLICATIONS

These findings demonstrate a crucial and age-dependent role for IL-33 in post-sepsis immunosuppression. Thus, a better understanding of this process may lead to differential treatments for adult and paediatric sepsis.

Unveiling the Role of Endoplasmic Reticulum Stress Pathways in Canine Demodicosis

Canine demodicosis is a prevalent skin disease caused by overpopulation of a commensal species of Demodex mite, yet its precise cause remains unknown. Research suggests that T-cell exhaustion, increased immunosuppressive cytokines, induction of regulatory T cells and increased expression of immune checkpoint inhibitors may contribute to its pathogenesis. This study aimed to gain a deeper understanding of the molecular changes occurring in canine demodicosis using mass spectrometry and pathway enrichment analysis. The results indicate that endoplasmic reticulum stress promotes canine demodicosis through regulation of three linked signalling pathways: eIF2, mTOR, and eIF4 and p70S6K. These pathways are involved in the modulation of Toll-like receptors, most notably TLR2, and have been shown to play a role in the pathogenesis of skin diseases in both dogs and humans. Moreover, these pathways are also implicated in the promotion of immunosuppressive M2 phenotype macrophages. Immunohistochemical analysis, utilising common markers of dendritic cells and macrophages, verified the presence of M2 macrophages in canine demodicosis. The proteomic analysis also identified immunological disease, organismal injury and abnormalities and inflammatory response as the most significant underlying diseases and disorders associated with canine demodicosis. This study demonstrates that Demodex mites, through ER stress, unfolded protein response and M2 macrophages contribute to an immunosuppressive microenvironment, thereby assisting in their proliferation.

M2 macrophage‑derived exosomes alleviate KCa3.1 channel expression in rapidly paced HL‑1 myocytes via the NF‑κB (p65)/STAT3 signaling pathway

The present study was designed to explore the role of M2 macrophage‑derived exosomes (M2‑exos) on the KCa3.1 channel in a cellular atrial fibrillation (AF) model using rapidly paced HL‑1 myocytes. M2 macrophages and M2‑exos were isolated and identified. MicroRNA (miR)‑146a‑5p levels in M2 macrophages and M2‑exos were quantified using reverse transcription‑quantitative PCR (RT‑qPCR). HL‑1 myocytes were randomly divided into six groups: Control group, pacing group, pacing + coculture group (pacing HL‑1 cells cocultured with M2‑exos), pacing + mimic‑miR‑146a‑5p group, pacing + NC‑miR‑146a‑5p group and pacing + pyrrolidine dithiocarbamate (PDTC; a special blocker of the NF‑κB signaling pathway) group. Transmission electron microscopy, nanoparticle tracking analysis, western blotting, RT‑qPCR and immunohistochemistry were performed in the present study. A whole‑cell clamp was also applied to record the current density of KCa3.1 and action potential duration (APD) in each group. The results revealed that miR‑146a‑5p was highly expressed in both M2 macrophages and M2‑exos. Pacing HL‑1 cells led to a shorter APD, an increased KCa3.1 current density and higher protein levels of KCa3.1, phosphorylated (p‑)NF‑κB p65, p‑STAT3 and IL‑1β compared with the control group. M2‑exos, miR‑146a‑5p‑mimic and PDTC both reduced the protein expression of KCa3.1, p‑NF‑κB p65, p‑STAT3 and IL‑1β and the current density of KCa3.1, resulting in a longer APD in the pacing HL‑1 cells. In conclusion, M2‑exos and their cargo, which comprised miR‑146a‑5p, decreased KCa3.1 expression and IL‑1β secretion in pacing HL‑1 cells via the NF‑κB/STAT3 signaling pathway, limiting the shorter APD caused by rapid pacing.

Therapeutic potential of ADSC-EV-derived lncRNA DLEU2: A novel molecular pathway in alleviating sepsis-induced lung injury via the miR-106a-5p/LXN axis

This study investigates the molecular mechanisms by which extracellular vesicles (EVs) derived from adipose-derived mesenchymal stem cells (ADSCs) promote M2 polarization of macrophages and thus reduce lung injury caused by sepsis. High-throughput sequencing was used to identify differentially expressed genes related to long non-coding RNA (lncRNA) in ADSC-derived EVs (ADSC-EVs) in sepsis lung tissue. Weighted gene co-expression network analysis (WGCNA) was employed to predict the downstream target genes of the lncRNA DLEU2. The RNAInter database predicted miRNAs that interact with DLEU2 and LXN. Functional and pathway enrichment analyses were performed using GO and KEGG analysis. A mouse model of sepsis was established, and treatment with a placebo or ADSC-EVs was administered, followed by RT-qPCR analysis. ADSC-EVs were isolated and identified. In vitro cell experiments were conducted using the mouse lung epithelial cell line MLE-12, mouse macrophage cell line RAW264.7, and mouse lung epithelial cell line (LEPC). ADSC-EVs were co-cultured with RAW264.7 and MLE-12/LEPC cells to study the regulatory mechanism of the lncRNA DLEU2. Cell viability, proliferation, and apoptosis of lung injury cells were assessed using CCK-8, EdU, and flow cytometry. ELISA was used to measure the levels of inflammatory cytokines in the sepsis mouse model, flow cytometry was performed to determine the number of M1 and M2 macrophages, lung tissue pathology was evaluated by H&E staining, and immunohistochemistry was conducted to examine the expression of proliferation- and apoptosis-related proteins. High-throughput sequencing and bioinformatics analysis revealed enrichment of the lncRNA DLEU2 in ADSC-EVs in sepsis lung tissue. Animal and in vitro cell experiments showed increased expression of the lncRNA DLEU2 in sepsis lung tissue after treatment with ADSC-EVs. Furthermore, ADSC-EVs were found to transfer the lncRNA DLEU2 to macrophages, promoting M2 polarization, reducing inflammation response in lung injury cells, and enhancing their viability, proliferation, and apoptosis inhibition. Further functional experiments indicated that lncRNA DLEU2 promotes M2 polarization of macrophages by regulating miR-106a-5p/LXN, thereby enhancing the viability and proliferation of lung injury cells and inhibiting apoptosis. Overexpression of miR-106a-5p could reverse the biological effects of ADSC-EVs-DLEU2 on MLE-12 and LEPC in vitro cell models. Lastly, in vivo animal experiments confirmed that ADSC-EVs-DLEU2 promotes high expression of LXN by inhibiting the expression of miR-106a-5p, further facilitating M2 macrophage polarization and reducing lung edema, thus alleviating sepsis-induced lung injury. lncRNA DLEU2 in ADSC-EVs may promote M2 polarization of macrophages and enhance the viability and proliferation of lung injury cells while inhibiting inflammation and apoptosis reactions, thus ameliorating sepsis-induced lung injury in a mechanism involving the regulation of the miR-106a-5p/LXN axis.

Single-cell sequencing analysis of chronic subdural hematoma cell subpopulations and their potential therapeutic mechanisms

BACKGROUND

Chronic subdural hematoma (CSDH) is a prevalent form of intracranial haemorrhage encountered in neurosurgical practice, and its incidence has notably risen in recent years. Currently, there is a lack of studies that have comprehensively classified the cells present in hematomas removed during surgery, and their correlation with CSDH recurrence remains elusive. This study aims to analyse the subcellular populations and occupancy levels within peripheral blood.

METHODS

This study analyses the subcellular populations and occupancy levels within peripheral blood and postoperatively removed hematomas by single-cell sequencing and attempts to analyse the effect of different cell occupancies within peripheral blood and intraoperatively removed hematomas on CSDH.

RESULTS

The single-cell sequencing results showed that the cells were classified into 25 clusters by differential gene and UMAP dimensionality reduction clustering analyses and further classified into 17 significant cell populations by cell markers: pDCs, CD8 T cells, CD4 T cells, MigDCs, cDC2s, cDC1s, plasma cells, neutrophils, naive B cells, NK cells, memory B cells, M2 macrophages, CD8 Teffs, CD8 MAIT cells, CD4 Tregs, CD19 B cells, and monocytes. Further research showed that the presence of more cDC2 and M2 macrophages recruited at the focal site in patients with CSDH and the upregulation of the level of T-cell occupancy may be a red flag for further brain damage. ROS, a marker of oxidative stress, was significantly upregulated in cDC2 cells and may mediate the functioning of transcription proteins of inflammatory factors, such as NFκB, which induced T cells' activation. Moreover, cDC2 may regulate M2 macrophage immune infiltration and anti-inflammatory activity by secreting IL1β and binding to M2 macrophage IL1R protein.

CONCLUSION

The detailed classification of cells in the peripheral blood and hematoma site of CSDH patients helps us to understand the mechanism of CSDH generation and the reduction in the probability of recurrence by regulating the ratio of cell subpopulations.

Nephroblastoma-specific dysregulated gene SNHG15 with prognostic significance: scRNA-Seq with bulk RNA-Seq data and experimental validation

Wilms tumor (WT) is the most common malignancy of the genitourinary system in children. Currently, the Integration of single-cell RNA sequencing (scRNA-Seq) and Bulk RNA sequencing (RNA-Seq) analysis of heterogeneity between different cell types in pediatric WT tissues could more accurately find prognostic markers, but this is lacking. RNA-Seq and clinical data related to WT were downloaded from the Therapeutically Applicable Research to Generate Effective Treatments (TARGET) database. Small nucleolar RNA host gene 15 (SNHG15) was identified as a risk signature from the TARGET dataset by using weighted gene co-expression network analysis, differentially expressed analysis and univariate Cox analysis. After that, the functional mechanisms, immunological and molecular characterization of SNHG15 were investigated at the scRNA-seq, pan-cancer, and RNA-seq levels using Gene ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG), ESTIMATE, and CIBERSORT. Based on scRNA-seq data, we identified 20 clusters in WT and annotated 10 cell types. Integration of single-cell and spatial data mapped ligand-receptor networks to specific cell types, revealing M2 macrophages as hubs for intercellular communication. In addition, in vitro cellular experiments showed that siRNAs interfering with SNHG15 significantly inhibited the proliferation and migration of G401 cells and promoted the apoptosis of G401 cells compared with the control group. The effect of siRNAs interfering with SNHG15 on EMT-related protein expression was verified by Western blotting assay. Thus, our findings will improve our current understanding of the pathogenesis of WT, and they are potentially valuable in providing novel prognosis markers for the treatment of WT.

Mammary tissue-derived extracellular matrix hydrogels reveal the role of irradiation in driving a pro-tumor and immunosuppressive microenvironment

Radiation therapy (RT) is essential for triple negative breast cancer (TNBC) treatment. However, patients with TNBC continue to experience recurrence after RT. The role of the extracellular matrix (ECM) of irradiated breast tissue in tumor recurrence is still unknown. In this study, we evaluated the structure, molecular composition, and mechanical properties of irradiated murine mammary fat pads (MFPs) and developed ECM hydrogels from decellularized tissues (dECM) to assess the effects of RT-induced ECM changes on breast cancer cell behavior. Irradiated MFPs were characterized by increased ECM deposition and fiber density compared to unirradiated controls, which may provide a platform for cell invasion and proliferation. ECM component changes in collagens I, IV, and VI, and fibronectin were observed following irradiation in both MFPs and dECM hydrogels. Encapsulated TNBC cell proliferation and invasive capacity was enhanced in irradiated dECM hydrogels. In addition, TNBC cells co-cultured with macrophages in irradiated dECM hydrogels induced M2 macrophage polarization and exhibited further increases in proliferation. Our study establishes that the ECM in radiation-damaged sites promotes TNBC invasion and proliferation as well as an immunosuppressive microenvironment. This work represents an important step toward elucidating how changes in the ECM after RT contribute to breast cancer recurrence.

Identification of Transcriptomic Signatures of Pancreatic Ductal Adenocarcinoma-Derived Exosomes That Promote Macrophage M2 Polarization and Predict Prognosis: S100A9 Reveals Tumor Progression

Background

Exosomes play a role in intercellular communication and participate in the interaction between pancreatic ductal adenocarcinoma (PDAC) cells and immune cells. Macrophages can receive tumor cell-derived exosomes to polarize into M2-type macrophages, which can enhance the invasion and metastasis of pancreatic cancer, leading to poor prognosis. However, the mechanism by which pancreatic cancer cell-derived exosomes promote M2-type macrophages is still unclear.

Methods

M2 macrophage-associated exosome-derived key module genes were identified by differentially expressed genes (DEGs) and weighted gene co-expression network analysis (WGCNA) analysis using exoRbase 2.0, The Cancer Genome Atlas (TCGA), and The International Cancer Genome Consortium (ICGC) databases. Multivariate Cox regression analysis was used to identify key prognostic genes and obtain regression coefficients to establish prognostic signature. Immune infiltration, tumor mutations, and GSEA among different risk groups were compared. exoRbase 2.0, Gene Expression Profiling Interactive Analysis 2 (GEPIA2), HPA, and TISCH2 databases were used to further analyze the expression pattern of S100A9 in pancreatic cancer. In vitro experiments, cell-derived exosome isolation, quantitative polymerase chain reaction (qPCR), western blot, flow cytometry analysis, cell transfection, transwell assay, and CCK-8 assay were applied to investigate the roles of S100A9 in macrophage M2 polarization and tumor progression.

Results

The key genes of PDAC-derived exosomes promoting M2-type macrophage polarization were identified, and a risk score model was established. The risk score is related to the expression of common immune checkpoints, immune score, and stromal score, and the tumor mutational burden and biological function of high- and low-risk groups were also different. S100A9 was positively correlated with M2-type macrophage marker. In addition, scRNA-seq data from the TISCH2 database revealed that S100A9 is predominantly expressed in pancreatic cancer cells and mono/macrophage cells, suggesting that S100A9 in pancreatic cancer cells could be received by macrophages, thereby inducing macrophage polarization. In vitro, we used exosomes from BxPC-3 cell lines to coculture macrophages and found that macrophages were mainly polarized toward M2 type, which further promoted the proliferation and metastasis of PDAC.

Conclusions

Our study established a reliable risk score model for PDAC-derived exosomes and M2 macrophages, identified the important role of S100A9 in macrophage M2 polarization, which provides a new strategy for the diagnosis and treatment of PDAC, and strengthened the understanding of the mechanism of tumor development and metastasis.

RSK4 promotes the macrophage recruitment and M2 polarization in esophageal squamous cell carcinoma

High infiltration of tumor-associated macrophages (TAMs) participates in host immunity and tumor progression in patients with esophageal squamous cell carcinoma (ESCC). Ribosomal s6 kinase 4 (RSK4) has been shown to be aberrantly overexpressed in ESCC. The role of RSK4 in cytokine secretion and its impact on macrophage recruitment and M2 polarization remains unclear. Therefore, a thorough understanding of RSK4 is needed to expand our knowledge of its therapeutic potential. Herein, RSK4 expression in human ESCC tissues and a xenograft mouse model was positively correlated with high infiltration of M0 and M2 macrophages which is positively associated with unfavorable overall survival outcomes and treatment resistance in patients with ESCC. In vitro experiments revealed that RSK4 derived from ESCC cells promoted macrophage recruitment and M2 polarization by enhancingsoluble intercellular adhesion molecule-1 (sICAM-1) secretion via direct and indirect STAT3 phosphorylation. Furthermore, RSK4-induced macrophages enhanced tumor proliferation, migration, and invasion by secreting C-C motif chemokine ligand 22 (CCL22). We further showed that patients with elevated CD68 and CD206 expression had unfavorable overall survival. Collectively, these results demonstrate that RSK4 promotes the macrophage recruitment and M2 polarization by regulating the STAT3/ICAM-1 axis in ESCC, influencing tumor progression primarily in a CCL22-dependent manner. These data also offer valuable insights for developing novel agents for the treatment of ESCC.

Cucurbitacin B modulates M2 macrophage differentiation and attenuates osteosarcoma progression via PI3K/AKT pathway

Osteosarcoma is a common malignant bone tumour characterised by an aggressive metastatic potential. The tumour microenvironment, particularly the M2-polarised macrophages, is crucial for tumour progression. Cucurbitacin B (CuB), a triterpenoid derivative, is recognised for its anti-inflammatory and antitumour properties. This study investigates CuB and its effect on M2 macrophage differentiation and osteosarcoma progression, aiming to contribute to new treatment strategies. In vitro, THP-1 monocytes were stimulated with PMA, IL-13 and IL-4 to induce differentiation into M2 macrophages. Additionally, the influence of CuB on the proliferation, migration and invasion of osteosarcoma cells in the context of M2 macrophages was scrutinised. Crucial signalling pathways, especially the PI3K/AKT pathway, affected by CuB were identified and validated. In vivo, the osteosarcoma model was employed to gauge the effects of CuB on tumour weight, lung metastasis, angiogenesis, cell proliferation and M2 macrophage markers. The results showed that CuB inhibited M2 macrophage differentiation, leading to reduced proliferation, migration and invasion of osteosarcoma cells. CuB manifested an inhibitory effect on the PI3K/AKT pathway during the differentiation of M2 macrophages. In mouse models, CuB markedly reduced the tumour weight and the number of lung metastases. It also reduced the expression of angiogenesis and cell proliferation markers in tumour tissues, decreased the quantity of M2 macrophages and their associated markers and pathway proteins. In conclusion, CuB impedes osteosarcoma progression by inhibiting M2 macrophage differentiation via the PI3K/AKT pathway, presenting the potential for therapeutic advancements in osteosarcoma treatment.

Multifunctional Exosomes Derived from M2 Macrophages with Enhanced Odontogenesis, Neurogenesis and Angiogenesis for Regenerative Endodontic Therapy: An In Vitro and In Vivo Investigation

INTRODUCTION

Exosomes derived from M2 macrophages (M2-Exos) exhibit tremendous potential for inducing tissue repair and regeneration. Herein, this study was designed to elucidate the biological roles of M2-Exos in regenerative endodontic therapy (RET) compared with exosomes from M1 macrophages (M1-Exos).

METHODS

The internalization of M1-Exos and M2-Exos by dental pulp stem cells (DPSCs) and human umbilical vein endothelial cells (HUVECs) was detected by uptake assay. The effects of M1-Exos and M2-Exos on DPSC and HUVEC behaviors, including migration, proliferation, odonto/osteogenesis, neurogenesis, and angiogenesis were determined in vitro. Then, Matrigel plugs incorporating M2-Exos were transplanted subcutaneously into nude mice. Immunostaining for vascular endothelial growth factor (VEGF) and CD31 was performed to validate capillary-like networks.

RESULTS

M1-Exos and M2-Exos were effectively absorbed by DPSCs and HUVECs. Compared with M1-Exos, M2-Exos considerably facilitated the proliferation and migration of DPSCs and HUVECs. Furthermore, M2-Exos robustly promoted ALP activity, mineral nodule deposition, and the odonto/osteogenic marker expression of DPSCs, indicating the powerful odonto/osteogenic potential of M2-Exos. In sharp contrast with M1-Exos, which inhibited the neurogenic capacity of DPSCs, M2-Exos contributed to a significantly augmented expression of neurogenic genes and the stronger immunostaining of Nestin. Consistent with remarkably enhanced angiogenic markers and tubular structure formation in DPSCs and HUVECs in vitro, the employment of M2-Exos gave rise to more abundant vascular networks, dramatically higher VEGF expression, and widely spread CD31+ tubular lumens in vivo, supporting the enormous pro-angiogenic capability of M2-Exos.

CONCLUSIONS

The multifaceted roles of M2-Exos in ameliorating DPSC and HUVEC functions potentially contribute to complete functional pulp-dentin complex regeneration.

Exosomes from ectopic endometrial stromal cells promote M2 macrophage polarization by delivering miR-146a-5p

BACKGROUND

Ectopic endometrial stromal cells (ESCs) and M2 macrophages co-exist in the lesions of endometriosis and participate in the occurrence and progression of endometriosis. However, the interaction between ectopic ESCs and M2-type macrophage polarization is poorly understood. This study aims to investigate the effect of exosomes released from ectopic ESCs on M2 macrophage polarization and the potential mechanism.

METHODS

Human THP-1 monocytic cells induced macrophage differentiation (M0) and M2 polarization. Ectopic ESCs and their exosomes were used to stimulate M2 macrophages. M2 macrophage polarization was examined by detecting CD163 and ARG1 expression. Exosomal microRNAs were analyzed by small-RNA sequencing.

RESULTS

Our in vitro results suggest that exosomes of ectopic ESCs promoted M2 macrophage polarization. Meanwhile, The miR-146a-5p level was highly increased in ectopic ESCs and their exosomes and promoted the role of exosomes in M2 macrophage polarization. As a target, TRAF6 overexpression inhibits the function of miR-146a-5p mimic on M2 macrophage polarization. In the rat model, exosomes from ectopic ESCs contribute to the development of endometriosis.

CONCLUSIONS

It was suggested that exosomes derived from ectopic ESCs promote the M2 macrophage polarization by delivering miR-146a-5p targeting TRAF6 in the pathological process of endometriosis.

Lianhua Qingwen protects LPS-induced acute lung injury by promoting M2 macrophage infiltration

ETHNOPHARMACOLOGICAL RELEVANCE

Traditional Chinese medicine Lianhua Qingwen (LHQW) was used to treat regular seasonal influenza. In recent years, LHQW exerts significant therapeutic effects in treating influenza and Coronavirus Disease 2019 (COVID-19). However, the potential mechanisms are not yet understood and need further study.

AIM OF STUDY

This study aims to look into the influence of LHQW on lung inflammation and macrophage phenotype, and to clarify the connection between macrophage plasticity and LHQW.

METHODS

The cell viability, marker expression, response to LPS stimulation, and phagocytosis of Raw264.7 were detected after LHQW treatment. In an LPS-induced acute lung injury (ALI) mouse model, the alleviating effect of LHQW on lung injury was investigated. The total macrophages and M2 macrophages in mice lungs and the peripheral blood monocytes after LHQW treatment were detected. The cell viability and polarization of peripheral blood macrophages treated with LHQW were detected.

RESULTS

Here, we demonstrate that LHQW protects LPS-induced ALI by promoting M2 macrophage infiltration. LHQW treatment inhibited the inflammatory response and pro-inflammatory phenotype of Raw264.7 macrophages. High concentrations of LHQW promoted the phagocytic capacity of Raw264.7 macrophages. In an ALI mouse model, LHQW alleviated lung injury and no significant hepatotoxicity was observed. By Immunohistochemistry (IHC) analysis, LHQW increased the infiltration of macrophages, mainly M2 macrophages. Consistent with Raw264.7, LHQW also decreased the expression of M1 markers in peripheral blood macrophages. In addition, LHQW blood plasma promoted the M2-type polarization of peripheral blood macrophages.

CONCLUSIONS

Taken together, our data demonstrate that LHQW reduces the inflammatory response and ameliorates acute lung injury by promoting anti-inflammatory polarization of macrophages.

Magnetic resonance imaging-based radiomics was used to evaluate the level of prognosis-related immune cell infiltration in breast cancer tumor microenvironment

PURPOSE

The tumor immune microenvironment is a valuable source of information for predicting prognosis in breast cancer (BRCA) patients. To identify immune cells associated with BRCA patient prognosis from the Cancer Genetic Atlas (TCGA), we established an MRI-based radiomics model for evaluating the degree of immune cell infiltration in breast cancer patients.

METHODS

CIBERSORT was utilized to evaluate the degree of infiltration of 22 immune cell types in breast cancer patients from the TCGA database, and both univariate and multivariate Cox regressions were employed to determine the prognostic significance of immune cell infiltration levels in BRCA patients. We identified independent prognostic factors for BRCA patients. Additionally, we obtained imaging features from the Cancer Imaging Archive (TCIA) database for 73 patients who underwent preoperative MRI procedures, and used the Least Absolute Shrinkage and Selection Operator (LASSO) to select the best imaging features for constructing an MRI-based radiomics model for evaluating immune cell infiltration levels in breast cancer patients.

RESULTS

According to the results of Cox regression analysis, M2 macrophages were identified as an independent prognostic factor for BRCA patients (HR = 32.288, 95% CI: 3.100-357.478). A total of nine significant features were selected to calculate the radiomics-based score. We established an intratumoral model with AUCs (95% CI) of 0.662 (0.495-0.802) and 0.678 (0.438-0.901) in the training and testing cohorts, respectively. Additionally, a peritumoral model was created with AUCs (95% CI) of 0.826 (0.710-0.924) and 0.752 (0.525-0.957), and a combined model was established with AUCs (95% CI) of 0.843 (0.723-0.938) and 0.744 (0.491-0.965). The peritumoral model demonstrated the highest diagnostic efficacy, with an accuracy, sensitivity, and specificity of 0.773, 0.727, and 0.818, respectively, in its testing cohort.

CONCLUSION

The MRI-based radiomics model has the potential to evaluate the degree of immune cell infiltration in breast cancer patients, offering a non-invasive imaging biomarker for assessing the tumor microenvironment in this disease.

A novel polysaccharide isolated from Coriolus versicolor polarizes M2 macrophages into an M1 phenotype and reversesits immunosuppressive effect on tumor microenvironment

Converting M2 macrophages into an M1 phenotype in the tumor microenvironment, provides a new direction for tumor treatment. Here, we further report CVPW-1, a new polysaccharide of 1.03 × 106 Da that was isolated from Coriolus versicolor. Its monosaccharide was composed of mannose, glucose, and galactose at a ratio of 1.00:8.73:1.68. The backbone of CVPW-1 was composed of (1 → 3)-linked α-D-Glcp residues and (1 → 3,6)-linked α-D-Glcp residues that branched at O-6. The branch consisted of (1 → 6)-linked α-D-Glcp residues and (1 → 4)-linked α-D-Glap, and some branches were terminated with (1→)-linked β-D-Manp residues according to the results of HPLC, FT-IR, GC-MS, 1D and 2D NMR. Meanwhile, CVPW-1 could polarize M2 macrophages to M1 phenotypein vitro by binding to TLR4 and inducing the activation of Akt, JNK and NF-κB. This process involved reversing the functional inhibition of CD8+ T lymphocytes by inhibiting the expression of TREM2 in M2 macrophages. The in vivo experiments showed that oral administration of CVPW-1 could inhibit the growth of tumor in mice and polarize TAMs to M1 phenotype. Thus, the novel polysaccharide CVPW-1 from Coriolus versicolor might activate a variety of immune cells and then play an anti-tumor role. These results demonstrated that CVPW-1 could be developed as a potential immuno-oncology treatment reagent.

The biointegration profile of fiber-reinforced plates following tibial implantation in sheep

Biointegrative, mineral fiber-reinforced bone fixation implants recently introduced in orthopedic surgery have expanded available treatment options for fractures and bone deformities. This new technology aims to address the disadvantages of permanent metallic implants while overcoming inherent concerns of adverse inflammatory reactions when using polymer-based orthopedic implants. The purpose of this double-arm preclinical study was to evaluate the safety, biocompatibility, and biointegration of fiber-reinforced plates, following implantation on the tibias of eight sheep. Left tibias underwent periosteal elevation, allowing for implant attachment directly onto the cortical surface; right tibia plates were implanted over intact periosteum. Microcomputed tomography and histopathology were performed at 13, 26, 52, 78, 104, and 134 weeks postimplantation. All animals were evaluated clinically at each time point, with no evidence of local adverse reactions. Histopathology demonstrated anti-inflammatory M2-like macrophages and multinucleated giant cells corresponding to implant bioabsorption, similar for both groups at each time point, and indicating expected implant biocompatibility. Inflammatory cells (i.e., eosinophils, lymphophyctes, plasma cells, and M1-like macrophages) were absent throughout the study. The bioabsorption process had started at 13 W, with the highest rate at 52-78 W. At 104 W, only residual polymer material was left (∼5% of implant area). Low amounts of mineral fibers were evident at 78 W and were absent (fully remodeled) by 104 W. At 134 W, implants at both sites were fully bioabsorbed. In conclusion, these new fiber-reinforced implants demonstrated bone remodeling and complete biointegration, with no adverse tissue response. Clinical significance: In this double-arm, 2.5-year study, a biointegrative, fiber-reinforced plate implanted on the tibias of sheep was fully absorbed within 134 weeks, with no adverse tissue reaction. Bioabsorption was similar, with or without periosteal elevation, mimicking conditions like those observed in traumatic injuries disrupting the periosteum, open reduction and internal fixation, or minimally invasive surgeries. These results demonstrate the feasibility, versatility, and safety of this new class of biointegrative bone implants. This newly developed technology avoids the complications of the removal of metal implants.

Regulator of G protein signaling-1 regulates immune infiltration and macrophage polarization in clear cell renal cell carcinoma

OBJECTIVE

To better understand how to clear cell renal cell cancer (ccRCC) is affected by the regulator of G protein signaling-1 (RGS1), its effect on immune infiltration, macrophage polarization, tumor proliferation migration, and to explore whether RGS1 may serve as a marker and therapeutic target for ccRCC.

PATIENTS AND METHODS

In this study, a total of 20 surgical specimens of patients with pathological diagnosis of ccRCC admitted to the Department of Urology of the Second Affiliated Hospital of Anhui Medical University from November 2021 to June 2022 were selected for pathological and protein testing, while the expression of RGS1 in tumors, immune infiltration, and macrophage polarization, particularly M2 macrophage linked to the development of tumor microenvironment (TME), were combined with TGCA database and GO analysis. We also further explored and studied the expression and function of RGS1 in TME, investigated how RGS1 affected tumor growth, migration, apoptosis, and other traits, and initially explored the signaling pathways and mechanisms that RGS1 may affect.

RESULTS

RGS1 was found to be expressed at higher quantities in ccRCC than in normal cells or tissues, according to bioinformatics analysis and preliminary experimental data from this work. Using the TCGA database and GO analysis to describe the expression of RGS1 in a range of tumors, it was found that ccRCC had a much higher level of RGS1 expression than other tumor types. The results of gene enrichment analysis indicated that overexpression of RGS1 may be associated with immune infiltration. The outcomes of in vitro tests revealed that RGS1 overexpression in ccRCC did not significantly alter the proliferation and migration ability of ccRCC, but RGS1 overexpression promoted apoptosis in ccRCC. By in vitro co-culture experiments, RGS1 overexpression inhibited M2 macrophage polarization and also suppressed the Jagged-1/Notch signaling pathway.

CONCLUSIONS

RGS1 is highly expressed in ccRCC, while overexpression of RGS1 may increase immune infiltration in the TME and reduce the polarization of M2 macrophages while promoting apoptosis in ccRCC.

The Importance of Th2 Immune Responses in Mediating the Progression of Gastritis-Associated Metaplasia to Gastric Cancer

Gastric cancer is one of the leading causes of cancer deaths worldwide, with chronic gastritis representing the main predisposing factor initiating the cascade of events leading to metaplasia and eventually progressing to cancer. A widely accepted classification distinguishes between autoimmune and environmental atrophic gastritis, mediated, respectively, by T cells promoting the destruction of the oxyntic mucosa, and chronic H. pylori infection, which has also been identified as the major risk factor for gastric cancer. The original dogma posits Th1 immunity as a main causal factor for developing gastritis and metaplasia. Recently, however, it has become evident that Th2 immune responses play a major role in the events causing chronic inflammation leading to tumorigenesis, and in this context, many different cell types and cytokines are involved. In particular, the activity of cytokines, such as IL-33 and IL-13, and cell types, such as mast cells, M2 macrophages and eosinophils, are intertwined in the process, promoting chronic gastritis-dependent and more diffuse metaplasia. Herein, we provide an overview of the critical events driving the pathology of this disease, focusing on the most recent findings regarding the importance of Th2 immunity in gastritis and gastric metaplasia.

CD206 modulates the role of M2 macrophages in the origin of metastatic tumors

Tumor metastasis is a key factor affecting the life of patients with malignant tumors. For the past hundred years, scientists have focused on how to kill cancer cells and inhibit their metastasis in vivo, but few breakthroughs have been made. Here we hypothesized a novel mode for cancer metastasis. We show that the phagocytosis of apoptotic tumor cells by macrophages leads to their polarization into the M2 phenotype, and that the expression of stem cell related as well as drug resistance related genes was induced. Therefore, it appears that M2 macrophages have "defected" and have been transformed into the initial "metastatic cancer cells", and thus are the source, at least in part, of the distal tissue tumor metastasis. This assumption is supported by the presence of fused cells with characteristics of both macrophage and tumor cell observed in the peripheral blood and ascites of patients with ovarian cancer. By eliminating the expression of CD206 in M2 macrophages using siRNA, we show that the growth and metastasis of tumors was suppressed using both in vitro cell line and with experimental in vivo mouse models. In summary, we show that M2 macrophages in the blood circulation underwent a "change of loyalty" to become "cancer cells" that transformed into distal tissue metastasis, which could be suppressed by the knockdown of CD206 expression.

Traversing through the Mechanistic Event Analysis in IL-6 and IL-17 Signaling for a New Therapeutic Paradigm in NSCLC

IL-6 and IL-17 are paradoxical cytokines that progress inflammatory states in chronic diseases, including cancer. In lung cancer, their role has been elucidated to favor cancer development by modulating signaling mechanisms critical to cellular growth. The intrinsic ability of these cytokines to influence macroautophagy is yet another reason to facilitate lung cancer. Here, we employed a systems immunology approach to discover the mechanistic role of these cytokines in cancer development. In a biological system, at later stages, the activation of NFkB stimulates immunosuppressive phenotypes to achieve tolerating effects in a transformed cell. We found that the upregulation of cytokines signaled M2 macrophages to modulate tumor responses through the activation of autophagic intermediates and inflammasome mediators. This caused immune perturbations in the tumor microenvironment, which were associated with cancer inflammation. To address these inflammatory states, we performed triggered event analysis to examine whether overexpressing immune effectors or downregulating immune suppressors may have an effect on cancer reversal. Interestingly, the inhibition of immune regulators opposed the model outcome to an increased immune response. Therefore, IL6-IL17-mediated regulation of lung cancer may address tumor malignancy and potentiate the development of newer therapeutics for NSCLC.

M2 macrophages-derived exosomes regulate osteoclast differentiation by the CSF2/TNF-α axis

BACKGROUND

Osteoclast-mediated bone resorption cause bone loss in several bone diseases. Exosomes have been reported to regulate osteoclast differentiation. M2-polarized macrophages exhibit anti-inflammatory activity. This study aimed to explore the effect of exosomes from M2 polarized macrophages (M2-exos) on osteoclastogenesis and molecular mechanisms.

METHODS

M2-exos were isolated from IL-4-induced Raw264.7 cells (M2 macrophages) and used to treat osteoclasts (RANKL-induced Raw264.7 cells). Osteoclast differentiation was visualized using tartrate resistant acid phosphatase staining. Quantitative real-time PCR (qPCR) was conducted to measure the levels of osteoclastogenesis-related genes. The underlying mechanisms of M2-exos were evaluated using qPCR and western blotting.

RESULTS

M2-exos suppressed osteoclast differentiation induced by RANKL. Additionally, CSF2 was highly expressed in M2 macrophages, and knockdown of CSF2 further enhanced the effects of M2-exos on osteoclast differentiation. Moreover, CSF2 positively regulated TNF-α signaling, which inhibition promoted differentiation of M2-exo-treated osteoclasts.

CONCLUSION

M2-exos inhibited RANKL-induced osteoclast differentiation by downregulating the CSF2 expression through inactivating the TNF-α signaling, suggesting the potential application of exosomes in bone disease therapy.

Water extracts of Tibetan medicine Wuweiganlu attenuates experimental arthritis via inducing macrophage polarization towards the M2 type

ETHNOPHARMACOLOGICAL RELEVANCE

Wuweiganlu (WGL) is a well-known formulation described in the "Four Medical Scriptures of Tibetan medicine", which is mainly used for the treatment of Rheumatoid Arthritis (RA) and other chronic ailments prescribed by Tibetan medicine. Nonetheless, the active constituents present in the water extracts of Wuweiganlu (WGLWE) specifically targeting arthritis treatment are largely unknown.

AIM OF THE STUDY

The aim of this study is to explore the effects and underlying mechanisms of the active components in WGLWE on RA.

MATERIALS AND METHODS

We utilized ultra-performance liquid chromatography coupled with Q-TOF mass spectrometry (UPLC-Q-TOF-MS) to identify the main chemical compositions of WGLWE. The polarization effect of WGLWE on bone marrow-derived macrophages (BMDM) was determined. A rat model of collagen-induced arthritis (CIA) was established by injecting an emulsion of bovine type II collagen mixed with an equal volume of incomplete Freund's adjuvant into the tail, paw and back of rats. A WGLWE-based ointment was topically applied to the legs and paws of the rats for 30 days. The rats' ankles were photographed to measure the degree of swelling. Micro-CT was used to image the knee joint and paw of rats, and the bone mineral density (BMD) and bone volume fraction (BV/TV) of knee joint in rats were analyzed. High-frequency ultrasound imaging of the rat knee joint was performed to observe knee joint effusion. Further, the serum levels of tumor necrosis factor (TNF-α), interleukin-6 (IL-6), IL-10, and arginine (Arg-1) in CIA rats were detected by enzyme-linked immunosorbent assay (ELISA). Immunohistochemistry (IHC) and immunofluorescence (IF) co-staining were employed to detect the expression levels of inflammatory factors in synovium.

RESULTS

A total of 28 main components were identified in WGLWE, and these compounds can directly bind to the inflammatory pathway proteins such as JAK2, NFκB and STAT3. In vitro experiments demonstrated that WGLWE promoted the transformation of M1 macrophages into M2 macrophages and suppressed the release of proinflammatory cytokines TNF-α and IL-6. In vivo studies showed that WGLWE effectively reduced ankle swelling, alleviated knee joint effusion, and improved BV/TV while also reducing synovial inflammation levels. Furthermore, WGLWE compounds induced the transition of M1-type macrophages to M2-type macrophages in synovial tissue, resulting in decreased secretion of inflammatory factors TNF-α, WGLWE improved the synovial inflammatory state.

CONCLUSION

Our results indicated that WGLWE alleviated joint inflammation in CIA rats and the underlying mechanism may be related to inducing the transformation of bone marrow-derived M1 macrophages to M2 macrophages, leading to an increase in the secretion of anti-inflammatory factors and a decrease in pro-inflammatory factors. Therefore, WGLWE may be used as a potential herbal preparation for the treatment of RA.

MFG-E8 facilitates heart repair through M1/M2 polarization after myocardial infarction by inhibiting CaMKII

BACKGROUND

M1/M2 macrophage polarization affects patient outcomes after myocardial infarction (MI). The relationship between milk fat globule-epidermal growth factor 8 (MFG-E8) and Ca2+/calmodulin-dependent protein kinase II (CaMKII) on macrophage polarization after MI is unknown. To investigate the functional role of MFG-E8 in modulating cardiac M1/M2 macrophage polarization after MI, especially its influence on CaMKII signaling.

METHODS

Human ventricular tissue and blood were obtained from patients with MI and controls. MFG-E8-KO mice were constructed (C57BL/6). The mice were randomized to WT-sham, sham-MFG-E8-KO, WT-PBS, rmMFG-E8 (WT injected with rmMFG-E8 10 min after MI), and MFG-E8-KO. The mouse macrophage cell line RAW264.7 was obtained. CaMKII, p-CaMKII, Akt, and NF-κB p65 were determined by qRT-PCR, western blot, and immunofluorescence.

RESULTS

The MFG-E8 levels were significantly enhanced after MI in the hearts and plasma of patients with MI compared with controls. The MFG-E8 levels were significantly increased in the hearts and plasma of mice after MI. MFG-E8 was derived from cardiac fibroblasts. The administration of rmMFG-E8 improved ventricular remodeling and cardiac function after MI. rmMFG-E8 did not suppress infiltrating monocyte/macrophages into the peri-infarct area. rmMFG-E8 suppressed the polarization of macrophages to the M1 phenotype and promoted the polarization of macrophages to the M2 phenotype. rmMFG-E8 suppressed CaMKII-dependent signaling in macrophages.

CONCLUSIONS

MFG-E8 and CaMKII appear to collaboratively regulate myocardial remodeling and M1/M2 macrophage polarization after MI. These observations suggest new roles for MFG-E8 in inhibiting M1 but promoting M2 macrophage polarization.

Tumor-associated macrophages and PD-L1 in prostate cancer: a possible key to unlocking immunotherapy efficacy

PURPOSE

Prostate cancer (PCa) is often considered as a "cold" tumor with low responsiveness to immunotherapy. Recent evidence suggests the activation of specific immune cells, such as tumor-associated macrophages (TAMs), could potentially influence the efficacy of immunotherapy in PCa. However, the relationship between TAMs and PD-L1, a significant regulator in immunotherapy, within PCa remains unexplored.

METHODS

In this study, we assessed TAM infiltration and PD-L1 expression levels in a local cohort of 95 PCa tissue samples and two publicly available PCa datasets. We employed a combination of bioinformatics and experimental techniques, including gene set enrichment analysis, CIBERSORTx, tissue microarray, immunohistochemistry staining, and analysis of single-cell sequencing datasets, to provide a comprehensive understanding of the association between PD-L1 and TAMs in the PCa microenvironment.

RESULTS

The study showed that CD68+ TAMs and CD163+ TAMs (M2-TAMs) were more abundant in the tumor microenvironment than in non-cancerous surrounding tissues. The infiltration of CD163+ TAMs was significantly associated with the Gleason score and risk stratification of PCa. Importantly, elevated PD-L1 expression correlated significantly with high infiltration of CD163+ TAMs. Furthermore, patients displaying high levels of CD163+ TAMs and PD-L1 expression exhibited shorter times to biochemical recurrence-free survival.

CONCLUSION

Our study suggests that CD163+ TAMs are closely associated with PD-L1 expression and can act as a valuable prognostic indicator for PCa. The high infiltration of M2-TAMs, coupled with the overexpression of PD-L1, may contribute to immune escape mechanisms in PCa, thereby influencing disease prognosis.

[Role of macrophage polarization in pulmonary diseases and intervention of traditional Chinese medicines]

As important immune cells, macrophages are a key factor involved in maintaining the homeostasis of the pulmonary microenvironment. Under different conditions, macrophages with high plasticity can be polarized into classically activated(M1) and selectively activated(M2) macrophages, which have pro-inflammatory and anti-inflammatory effects, respectively. M1/M2 phenotype is associated with the occurrence and development of pulmonary diseases. A variety of information molecules and cytokines involved in the polarization of macrophages play a role in regulating phenotypes in pulmonary diseases, and the phenotype transformation varies significantly in different diseases. This paper introduces the biological characteristics of macrophage polarization and expounds the roles of macrophage polarization in bronchial asthma, chronic obstructive pulmonary disease, acute lung injury, and pulmonary fibrosis. Moreover, the research progress in the regulation of macrophage polarization by the active components in traditional Chinese medicine(TCM) and the TCM compound prescriptions in the treatment of pulmonary diseases was reviewed. This review aims to explore the potential of macrophage polarization in regulating pulmonary inflammation and provide new ideas for related clinical research.

Effects of glass-ceramic produced by the sol-gel route in macrophages recruitment and polarization into bone tissue regeneration

Effective bone substitute biomaterials remain an important challenge in patients with large bone defects. Glass ceramics produced by different synthesis routes may result in changes in the material physicochemical properties and consequently affect the success or failure of the bone healing response. To investigate the differences in the orchestration of the inflammatory and healing process in bone grafting and repair using different glass-ceramic routes production. Thirty male Wistar rats underwent surgical unilateral parietal defects filled with silicate glass-ceramic produced by distinct routes: BS - particulate glass-ceramic produced via the fusion/solidification route, and BG - particulate glass-ceramic produced via the sol-gel route. After 7, 14, and 21 days from biomaterial grafting, parietal bones were removed to be analyzed under H&E and Massons' Trichome staining, and immunohistochemistry for CD206, iNOS, and TGF-β. Our findings demonstrated that the density of lymphocytes and plasma cells was significantly higher in the BS group at 45, and 7 days compared to the BG group, respectively. Furthermore, a significant increase of foreign body giant cells (FBGCs) in the BG group at day 7, compared to BS was found, demonstrating early efficient recruitment of FBGCs against sol-gel-derived glass-ceramic particulate (BS group). According to macrophage profiles, CD206+ macrophages enhanced at the final periods of both groups, being significantly higher at 45 days of BS compared to the BG group. On the other hand, the density of transformation growth factor beta (TGF-β) positive cells on 21 days were the highest in BG, and the lowest in the BS group, demonstrating a differential synergy among groups. Noteworthy, TGF-β+ cells were significantly higher at 21 days of BG compared to the BS group. Glass-ceramic biomaterials can act differently in the biological process of bone remodeling due to their route production, being the sol-gel route more efficient to activate M2 macrophages and specific FBGCs compared to the traditional route. Altogether, these features lead to a better understanding of the effectiveness of inflammatory response for biomaterial degradation and provide new insights for further preclinical and clinical studies involved in bone healing.

Inhibition of cGAS-STING pathway by stress granules after activation of M2 macrophages by human mesenchymal stem cells against drug induced liver injury

OBJECTIVE

Cells can produce stress granules (SGs) to protect itself from damage under stress. The cGAS-STING pathway is one of the important pattern recognition pathways in the natural immune system. This study was investigated whether human mesenchymal stem cells (hMSCs) could protect the liver by inducing M2 macrophages to produce SGs during acute drug induced liver injury (DILI) induced by acetaminophen (APAP).

METHODS

After intragastric administration of APAP in vivo to induce DILI mice model, hMSCs were injected into the tail vein. The co-culture system of hMSCs and M2 macrophages was established in vitro. It was further use SGs inhibitor anisomicin to intervene M2 macrophages. The liver histopathology, liver function, reactive oxygen species (ROS) level, apoptosis pathway, endoplasmic reticulum stress (ERS) level, SGs markers (G3BP1/TIA-1), cGAS-STING pathway, TNF-α, IL-6, IL-1β mRNA levels in liver tissue and M2 macrophages were observed.

RESULTS

In vivo experiments, it showed that hMSCs could alleviate liver injury, inhibite the level of ROS, apoptosis and ERS, protect liver function in DILI mice. The mount of M2 was increased in the liver. hMSCs could also induce the production of SGs, inhibit the cGAS-STING pathway and reduce TNF-α, IL-6, IL-1β mRNA expression. The results in vitro showed that hMSCs could induce the production of SGs in macrophages, inhibit the cGAS-STING pathway, promote the secretion of IL-4 and IL-13, and reduce TNF-α, IL-6, IL-1β mRNA level in cells. In the process of IL-4 inducing M2 macrophage activation, anisomycin could inhibit the production of SGs, activate the cGAS-STING pathway, and promote the inflammatory factor TNF-α, IL-6, IL-1β mRNA expression in cells.

CONCLUSIONS

HMSCs had a protective effect on acute DILI in mice induced by APAP. Its mechanism might involve in activating M2 type macrophages, promoting the production of SGs, inhibiting the cGAS-STING pathway, and reducing the expression of pro-inflammatory factors in macrophages, to reduce hepatocytes damage.

Targeting crosstalk of STAT3 between tumor-associated M2 macrophages and Tregs in colorectal cancer

A comprehensive analysis of the molecular mechanism underlying colorectal tumor evaluated the development of colorectal cancer (CRC) and proposed targeting small molecular inhibitors. Nonetheless, the adoptive resistance of these therapies remains a challenge with respect to achieving an effective clinical response. Thus, identifying the molecular mechanisms guiding CRC growth is essential. The results of The Cancer Genome Atlas (TCGA) dataset analysis demonstrated a critical role of signal transducer and activator of transcription 3 (STAT3) pathway in tumor immune suppression via modulation of the recruitment of Treg cells and M2 type tumor-associated macrophages. The in vivo experiments elucidate that targeting STAT3 pathways markedly reduce the proportions of TAMs and Tregs by inhibiting tumor progression. These findings revealed crosstalk between Treg cells and M2 macrophages, proving a potential therapeutic strategy for CRC therapy. Combinatorial treatment with STAT3 inhibitor and programmed death 1 (PD-1) antibody therapy effectively prevents CRC tumor growth in a mouse model with high anti-tumor immunity. In summary, targeting STAT3 disrupts the interaction between Treg cells and M2 macrophages and improves the anti-tumor response in CRC, thereby offering a promising strategy to treat patients with CRC.

Fecal Supernatants from Patients with Crohn's Disease Induce Inflammatory Alterations in M2 Macrophages and Fibroblasts

Intestinal macrophages and fibroblasts act as microenvironmental sentinels mediating inflammation and disease progression in Crohn's disease (CD). We aimed to establish the effects of fecal supernatants (FSs) from patients with CD on macrophage and fibroblast phenotype and function. FS were obtained by ultracentrifugation, and the metabolites were analyzed. Monocyte-derived M2 macrophages and fibroblasts were conditioned with FS, and secreted proteins, surface proteins and gene expression were analyzed. M2 macrophage efferocytosis was evaluated. Patients with CD (n = 15) had a skewed fecal metabolite profile compared to healthy subjects (HS, n = 10). FS from CD patients (CD-FS) induced an anti-inflammatory response in M2 macrophages with higher expression of IL-10, IL1RA and CD206 as compared to healthy FS (HS-FS) while the efferocytotic capacity was unaltered. CD-FS did not affect extracellular matrix production from fibroblasts, but increased expression of the pro-inflammatory proteins IL-6 and MCP-1. Conditioned media from M2 macrophages treated with CD-FS modulated gene expression in fibroblasts for TGFβ superfamily members and reduced IL-4 expression compared to HS-FS. We show that M2 macrophages and fibroblasts react abnormally to the fecal microenvironment of CD patients, resulting in altered protein expression related to inflammation but not fibrosis. This implies that the gut microbiota and its metabolites have an important role in the generation and/or perpetuation of inflammation in CD.

Treponema pallidum Promotes the Polarization of M2 Subtype Macrophages to M1 Subtype Mediating the Apoptosis and Inhibiting the Angiogenesis of Human Umbilical Vein Endothelial Cells

M2 macrophages were related to local immune homeostasis and maternal-fetal tolerance in normal pregnancy; whether M2 macrophages can respond to the stimulation of Treponema pallidum to mediate placental vascular inflammation injury is unclear. In this study, M2 macrophages were constructed to investigate the impact of T. pallidum on macrophage polarization and the underlying signaling pathway involved in this process, and the influence of macrophage polarization triggered by T. pallidum on the apoptosis and angiogenesis of human umbilical vein endothelial cells (HUVEC) was also explored. The results showed that M2 macrophage markers (CD206 and PPARγ) and anti-inflammatory factors (TGFβ and CCL18) were decreased, while M1 macrophage marker CD80 and inflammatory cytokines (IL1β and TNFα) were increased when M2 macrophages were treated with T. pallidum, indicating that T. pallidum promoted the polarization of M2 subtype macrophages to the M1 subtype. Moreover, T. pallidum-induced M1 macrophage polarization was found to be significantly correlated with the activation of Janus kinase 1 (JAK1) and signal transducer and activator of transcription 1 (STAT1). In addition, T. pallidum-induced M1 macrophages were found to promote apoptosis and inhibit the angiogenesis of HUVECs, and JAK1 or STAT1 inhibitors could weaken the apoptosis rate and promote the angiogenesis of HUVECs. These findings revealed that T. pallidum promoted the polarization of M2 macrophages to the M1 subtype through the JAK1-STAT1 signal pathway mediating the apoptosis and inhibiting angiogenesis of HUVECs, which may provide a possible mechanism for T. pallidum-induced adverse pregnancy outcomes.

Progress in Understanding the Role and Therapeutic Targets of Polarized Subtypes of Macrophages in Pulmonary Fibrosis

Pulmonary fibrosis represents the advanced phase of diverse pulmonary ailments, and at present, a definitive cure for these ailments is lacking. Furthermore, underlying mechanisms causative of these ailments remain elusive. Macrophages are immune cells that resist external stimuli in the early stages after birth. These cells can polarize into the classically (M1) and alternatively (M2) activated macrophages. When stimulated owing to the presence of toxic factors, M1 macrophages produce several pro-inflammatory factors, which mediate the inflammatory injury response of the alveolar tissue. The secretion of diverse growth factors by M2 macrophages contributes to the pathogenesis of aberrant alveolar structural fibrosis and remodeling. The abnormal activity of M2 macrophages is considered a critical factor in the formation of pulmonary fibrosis. In this mini-review, to highlight the clinical implications of research studies, we summarize the role and therapeutic targets of polarized subtypes of macrophages in pulmonary fibrosis and the role of targeting macrophages for the treatment of pulmonary fibrosis.

Inhibition of inflammation and infiltration of M2 macrophages in NSCLC through the ATF3/CSF1 axis: Role of miR-27a-3p

Non-small cell lung cancer (NSCLC) imposes a significant economic burden on patients and society due to its low overall cure and survival rates. Tumour-associated macrophages (TAM) affect tumour development and may be a novel therapeutic target for cancer. We collected NSCLC and tumour-adjacent tissue samples. Compared with the tumour-adjacent tissues, the Activation Transcription Factor 3 (ATF3) and Colony Stimulating Factor 1 (CSF-1) were increased in NSCLC tissues. Levels of ATF3 and CSF-1 were identified in different cell lines (HBE, A549, SPC-A-1, NCI-H1299 and NCI-H1795). Overexpression of ATF3 in A549 cells increased the expression of CD68, CD206 and CSF-1. Moreover, levels of CD206, CD163, IL-10 and TGF-β increased when A549 cells were co-cultured with M0 macrophages under the stimulation of CSF-1. Using the starbase online software prediction and dual-luciferase assays, we identified the targeting between miR-27a-3p and ATF3. Levels of ATF3, CSF-1, CD206, CD163, IL-10 and TGF-β decreased in the miR-27a mimics, and the tumour growth was slowed in the miR-27a mimics compared with the mimics NC group. Overall, the study suggested that miR-27a-3p might inhibit the ATF3/CFS1 axis, regulate the M2 polarization of macrophages and ultimately hinder the progress of NSCLC. This research might provide a new therapeutic strategy for NSCLC.

Qijia rougan formula ameliorates ECM deposition in hepatic fibrosis by regulating the JAK1/STAT6-microRNA-23a feedback loop in macrophage M2 polarization

Hepatic fibrosis is the critical pathological stage in the progression of chronic liver disease to cirrhosis and hepatocellular carcinoma (HCC). However, no approved anti-hepatic fibrosis drugs are available currently. Qijia Rougan Formula (QRF) is a traditional Chinese medicine (TCM) with significant clinical efficacy on hepatic fibrosis. It was derived from Sanjiasan, a famous decoction documented in the Book of Treatise on the Pestilence in the Ming Dynasty of China. However, the underlying regulatory mechanisms remain elusive. This study further confirmed the therapeutic effects of QRF on hepatic fibrosis and dissected its underlying molecular mechanisms from the perspective of macrophage M2 polarization, one of the critical events in hepatic fibrosis. Experimentally, QRF significantly improved extracellular matrix (ECM) deposition and fibrosis in the liver of model rats. QRF diminished the proportion of M2 macrophages, decreased the levels of TGF-β, PDGFB and IL-10, and regulated the expression of p-JAK1, p-STAT6, JAK1 and microRNA-23a both in vitro and in vivo. Collectively, it was confirmed that QRF effectively improves liver function and hepatocyte damage, and reduces ECM deposition. QRF ameliorates hepatic fibrosis by regulating JAK1/STAT6-microRNA-23a negative feedback loop to inhibit macrophage M2 polarization and thus reduce ECM deposition. Our study illustrates the potential of QRF for hepatic fibrosis therapy, suggesting that QRF is a promising anti-hepatic fibrosis drug candidate.

Human Bone Marrow Mesenchymal Stem Cells Promote the M2 Phenotype in Macrophages Derived from STEMI Patients

Acute ST-elevation myocardial infarction (STEMI) leads to myocardial injury or necrosis, and M1 macrophages play an important role in the inflammatory response. Bone marrow mesenchymal stem/stromal cells (BM-MSCs) are capable of modulating macrophage plasticity, principally due to their immunoregulatory capacity. In the present study, we analyzed the capacity of MSCs to modulate macrophages derived from monocytes from patients with STEMI. We analyzed the circulating levels of cytokines associated with M1 and M2 macrophages in patients with STEMI, and the levels of cytokines associated with M1 macrophages were significantly higher in patients with STEMI than in controls. BM-MSCs facilitate the generation of M1 and M2 macrophages. M1 macrophages cocultured with MSCs did not have decreased M1 marker expression, but these macrophages had an increased expression of markers of the M2 macrophage phenotype (CD14, CD163 and CD206) and IL-10 and IL-1Ra signaling-induced regulatory T cells (Tregs). M2 macrophages from patients with STEMI had an increased expression of M2 phenotypic markers in coculture with BM-MSCs, as well as an increased secretion of anti-inflammatory cytokines and an increased generation of Tregs. The findings in this study indicate that BM-MSCs have the ability to modulate the M1 macrophage response, which could improve cardiac tissue damage in patients with STEMI.

Key role of exosomes derived from M2 macrophages in maintaining cancer cell stemness (Review)

Cancer stem cells (CSCs) constitute a specific subset of cells found within tumors that are responsible for initiating, advancing and resisting traditional cancer treatments. M2 macrophages, also known as alternatively activated macrophages, contribute to the development and progression of cancer through their involvement in promoting angiogenesis, suppressing the immune system, supporting tumor growth and facilitating metastasis. Exosomes, tiny vesicles released by cells, play a crucial role in intercellular communications and have been shown to be associated with cancer development and progression by influencing the immune response; thus, they may serve as markers for diagnosis and prognosis. Currently, investigating the impact of exosomes derived from M2 macrophages on the maintenance of CSCs is a crucial area of research with the aim of developing novel therapeutic strategies to target this process and improve outcomes for individuals with cancer. Understanding the biological functions of exosomes derived from M2 macrophages and their involvement in cancer may lead to the formulation of novel diagnostic tools and treatments for this disease. By targeting M2 macrophages and the exosomes they secrete, promising prospects emerge for cancer treatment, given their substantial contribution to cancer development and progression. Further research is required to fully grasp the intricate interactions between CSCs, M2 macrophages and exosomes in cancer, and to identify fresh targets for cancer therapy. The present review explores the pivotal roles played by exosomes derived from M2 cells in maintaining the stem‑like properties of cancer cells.

IGF2BP3 drives gallbladder cancer progression by m6A-modified CLDN4 and inducing macrophage immunosuppressive polarization

INTRODUCTION

N6-methyladenosine (m6A) is an emerging epigenetic modification, which plays a crucial role in the development of cancer. Nevertheless, the underlying mechanism of m6A-associated proteins and m6A modification in gallbladder cancer remains largely unknown.

MATERIALS AND METHODS

The Gene Expression Omnibus database and tissue microarray were used to identify the key m6A-related gene in gallbladder cancer. The function and mechanism of IGF2BP3 were further investigated by knockdown and overexpression techniques in vitro and in vivo.

RESULTS

We found that IGF2BP3 was elevated and correlated with poor prognosis in gallbladder cancer, which can be used as an independent prognostic factor for gallbladder cancer. IGF2BP3 accelerated the proliferation, invasion and migration of gallbladder cancer cells in vitro and in vivo. Mechanistically, IGF2BP3 interacted with and augmented the stability of CLDN4 mRNA by m6A modification. Enhancement of CLDN4 reversed the inhibitory effect of IGF2BP3 deficiency on gallbladder cancer. Furthermore, we demonstrated that IGF2BP3 promotes the activation of NF-κB signaling pathway by up-regulation of CLDN4. Overexpression of IGF2BP3 in gallbladder cancer cells obviously promoted the polarization of immunosuppressive phenotype in macrophages. Besides, Gallbladder cancer cells-derived IGF2BP3 up-regulated the levels of STAT3 in M2 macrophages, and promoted M2 polarization.

CONCLUSIONS

We manifested IGF2BP3 promotes the aggressive phenotype of gallbladder cancer by stabilizing CLDN4 mRNA in an m6A-dependent manner and induces macrophage immunosuppressive polarization, which might offer a new theoretical basis for against gallbladder cancer.

Mechanism of M2 type macrophage-derived extracellular vesicles regulating PD-L1 expression via the MISP/IQGAP1 axis in hepatocellular carcinoma immunotherapy resistance

BACKGROUND

Hepatocellular carcinoma (HCC) is a prevailing cancer affecting human health. M2 macrophages are essential in mediating immune responses in tumors. This study investigated the action of M2 macrophages in immune escape of HCC.

METHODS

Mitotic spindle positioning (MISP), IQ motif containing GTPase activating protein 1 (IQGAP1) and programmed cell death-1 (PD-L1) levels in primary HCC/tumor-adjacent tissues were determined by Western blot, followed by correlation analysis. M2 macrophage and CD3+CD8+T cell percentages were estimated by flow cytometry. Hep3B and HepG2 cells were treated with M2 macrophage conditioned medium (M2-CM) and M2 macrophage-derived extracellular vesicles (M2-EVs) and/or co-cultured with CD8+T cells, followed by assessment of cell viability and apoptosis. TNF-α and INF-γ levels were measured by ELISA. MISP and IQGAP1 overexpression plasmids were transfected into HCC cells to explore their role in immune escape. The interactions among MISP, IQGAP1, STAT3, and PD-L1 were analyzed by co-immunoprecipitation. The mechanism of M2-EVs in HCC immune escape was verified in nude mice.

RESULTS

MISP/IQGAP1/PD-L1 were upregulated in HCC tissues. MISP negatively-correlated with IQGAP1/PD-L1 and IQGAP1 positively-correlated with PD-L1. M2 macrophages were reduced but CD8+T cells were increased in HCC tissues with high MISP expression. M2-CM or M2-EVs inhibited the killing ability of CD8+T cells, increased HCC cell viability, impeded HCC cell apoptosis, induced CD8+T cell apoptosis, downregulated TNF-α and INF-γ, and upregulated PD-L1. M2-EVs facilitated HCC cell immune escape by potentiating IQGAP1 nuclear translocation and activating STAT3 phosphorylation through MISP downregulation. In vivo experiments further verified the action of M2-EVs through MISP.

CONCLUSION

M2-EVs promote HCC cell immune escape by upregulating PD-L1 through the MISP/IQGAP1/STAT3 axis.

Identifying Immune Cell Infiltration and Hub Genes Related to M2 Macrophages in Endometriosis by Bioinformatics Analysis

Endometriosis (EM) is a chronic, estrogen-dependent inflammatory disease. Presently, the pathophysiology of EM is still unclear, and numerous studies have established that the immune system plays a major role in the pathophysiology of EM. Six microarray datasets were downloaded from the GEO public database. A total of 151 endometrial samples (72 ectopic endometria and 79 controls) were included in this study. CIBERSORT and ssGSEA were applied to calculate the immune infiltration of EM and control samples. Moreover, we validated four different correlation analyses to explore immune microenvironment of EM and finally identified M2 macrophage-related hub genes and further conducted the specific immunologic signaling pathway analysis by GSEA. The logistic regression model was investigated by ROC and further validated by two external datasets. From the results of the two immune infiltration assays, we concluded that M2 macrophages, regulatory T cells (Tregs), M1 macrophages, activated B cells, T follicular helper cells, activated dendritic cells, and resting NK cells have a significant difference between control and EM tissues. Through multidimensional correlation analysis, we found that macrophages play an important central role in cell-to-cell interactions, especially M2 macrophages. Four immune-related hub genes, namely FN1, CCL2, ESR1, and OCLN, are closely related to M2 macrophages and play a crucial role in the occurrence and immune microenvironment of endometriosis. The combined AUC of ROC prediction model in test and validation sets were 0.9815 and 0.8206, respectively. We conclude that M2 macrophages play a central role in the immune-infiltrating microenvironment of EM.

24-Norursodeoxycholic acid ameliorates experimental alcohol-related liver disease and activates hepatic PPARγ

Background & Aims

Alcohol-related liver disease (ALD) is a global healthcare challenge with limited treatment options. 24-Norursodeoxycholic acid (NorUDCA) is a synthetic bile acid with anti-inflammatory properties in experimental and human cholestatic liver diseases. In the present study, we explored the efficacy of norUDCA in experimental ALD.

Methods

NorUDCA was tested in a preventive and therapeutic setting in an experimental ALD model (Lieber-DeCarli diet enriched with ethanol). Liver disease was phenotypically evaluated using histology and biochemical methods, and anti-inflammatory properties and peroxisome proliferator-activated receptor gamma activation by norUDCA were evaluated in cellular model systems.

Results

NorUDCA administration ameliorated ethanol-induced liver injury, reduced hepatocyte death, and reduced the expression of hepatic pro-inflammatory cytokines including tumour necrosis factor (Tnf), Il-1β, Il-6, and Il-10. NorUDCA shifted hepatic macrophages towards an anti-inflammatory M2 phenotype. Further, norUDCA administration altered the composition of the intestinal microbiota, specifically increasing the abundance of Roseburia, Enterobacteriaceae, and Clostridum spp. In a therapeutic model, norUDCA also ameliorated ethanol-induced liver injury. Moreover, norUDCA suppressed lipopolysaccharide-induced IL-6 expression in human peripheral blood mononuclear cells and evoked peroxisome proliferator-activated receptor gamma activation.

Conclusions

NorUDCA ameliorated experimental ALD, protected against hepatic inflammation, and affected gut microbial commensalism. NorUDCA could serve as a novel therapeutic agent in the future management of patients with ALD.

Impact and implications

Alcohol-related liver disease is a global healthcare concern with limited treatment options. 24-Norursodeoxycholic acid (NorUDCA) is a modified bile acid, which was proven to be effective in human cholestatic liver diseases. In the present study, we found a protective effect of norUDCA in experimental alcoholic liver disease. For patients with ALD, norUDCA could be a potential new treatment option.

Reduced angiogenesis and delayed endochondral ossification in CD163-/- mice highlights a role of M2 macrophages during bone fracture repair

While recent studies showed that macrophages are critical for bone fracture healing, and lack of M2 macrophages have been implicated in models of delayed union, functional roles for specific M2 receptors have yet to be defined. Moreover, the M2 scavenger receptor CD163 has been identified as a target to inhibit sepsis following implant-associated osteomyelitis, but potential adverse effects on bone healing during blockage therapy have yet to be explored. Thus, we investigated fracture healing in C57BL/6 versus CD163-/- mice using a well-established closed, stabilized, mid-diaphyseal femur fracture model. While gross fracture healing in CD163-/- mice was similar to that of C57BL/6, plain radiographs revealed persistent fracture gaps in the mutant mice on Day 14, which resolved by Day 21. Consistently, 3D vascular micro-CT demonstrated delayed union on Day 21, with reduced bone volume (74%, 61%, and 49%) and vasculature (40%, 40%, and 18%) compared to C57BL/6 on Days 10, 14, and 21 postfracture, respectively (p < 0.01). Histology confirmed large amounts of persistent cartilage in CD163-/- versus C57BL/6 fracture callus on Days 7 and 10 that resolves over time, and immunohistochemistry demonstrated deficiencies in CD206+ M2 macrophages. Torsion testing of the fractures confirmed the delayed early union in CD163-/- femurs, which display decreased yield torque on Day 21, and a decreased rigidity with a commensurate increase in rotation at yield on Day 28 (p < 0.01). Collectively, these results demonstrate that CD163 is required for normal angiogenesis, callus formation, and bone remodeling during fracture healing, and raise potential concerns about CD163 blockade therapy.

M2 macrophage-secreted exosomes promote metastasis and increase vascular permeability in hepatocellular carcinoma

BACKGROUND

Metastasis is a key feature of malignant tumors and significantly contributes to their high mortality, particularly in hepatocellular carcinoma (HCC). Therefore, it is imperative to explore the mechanism of tumor metastasis. Recently, tumor-associated macrophages (TAMs) have been demonstrated to promote tumor progression, while TAM-derived molecules involved in HCC metastasis warrant further investigation.

METHODS

THP-1 was treated with IL-4 (Interleukin-4) and IL-13 (Interleukin-13) for M2 polarized macrophages. Exosomes derived from M2 macrophages were characterized. Then, HCC cells or human umbilical vein endothelial cells (HUVECs) were co-cultured with M2 macrophages or treated with M2 macrophage-secreted exosomes. Next, Transwell®, Scratch assay, tube formation, and endothelial permeability assays were performed. Moreover, RT-PCR, western blotting, immunofluorescence, and ELISA were used to assess mRNA and protein expression levels. Finally, the miRNA expression profiles of exosomes derived from M2 and M0 macrophages were analyzed.

RESULTS

M2 macrophage infiltration was correlated with metastasis and a poor prognosis in HCC patients. M2-derived exosomes were absorbed by HCC and HUVEC cells and promoted the epithelial-mesenchymal transition (EMT), vascular permeability, and angiogenesis. Notably, MiR-23a-3p levels were significantly higher in M2-derived exosomes and hnRNPA1 mediated miR-23a-3p packaging into exosomes. Phosphatase and tensin homolog (PTEN) and tight junction protein 1 (TJP1) were the targets of miR-23a-3p, as confirmed by luciferase reporter assays. Lastly, HCC cells co-cultured with M2-derived exosomes secreted more GM-CSF, VEGF, G-CSF, MCP-1, and IL-4, which in turn further recruited M2 macrophages.

CONCLUSIONS

Our findings suggest that M2 macrophage-derived miR-23a-3p enhances HCC metastasis by promoting EMT and angiogenesis, as well as increasing vascular permeability. Video Abstract.

CXCL13 promotes thermogenesis in mice via recruitment of M2 macrophage and inhibition of inflammation in brown adipose tissue

Introduction

Brown adipose tissue (BAT) is mainly responsible for mammalian non-shivering thermogenesis and promotes energy expenditure. Meanwhile, similar to white adipose tissue (WAT), BAT also secretes a variety of adipokines to regulate metabolism through paracrine, autocrine, or endocrine ways. The chemokine C-X-C motif chemokine ligand-13 (CXCL13), a canonical B cell chemokine, functions in inflammation and tumor-related diseases. However, the role of CXCL13 in the adipose tissues is unclear.

Methods

The expression of CXCL13 in BAT and subcutaneous white adipose tissue (SWAT) of mice under cold stimulation were detected. Local injection of CXCL13 into BAT of normal-diet and high-fat-diet induced obese mice was used to detect thermogenesis and determine cold tolerance. The brown adipocytes were treated with CXCL13 alone or in the presence of macrophages to determine the effects of CXCL13 on thermogenic and inflammation related genes expression in vitro.

Results

In this study, we discovered that the expression of CXCL13 in the stromal cells of brown adipose tissue significantly elevated under cold stimulation. Overexpression of CXCL13 in the BAT via local injection could increase energy expenditure and promote thermogenesis in obese mice. Mechanically, CXCL13 could promote thermogenesis via recruiting M2 macrophages in the BAT and, in the meantime, inhibiting pro-inflammatory factor TNFα level.

Discussion

This study revealed the novel role of adipose chemokine CXCL13 in the regulation of BAT activity and thermogenesis.

GPR37 expression as a prognostic marker in gliomas: a bioinformatics-based analysis

BACKGROUND

Gliomas are the most frequently diagnosed primary brain tumors, and are associated with multiple molecular aberrations during their development and progression. GPR37 is an orphan G protein-coupled receptor (GPCR) that is implicated in different physiological pathways in the brain, and has been linked to various malignancies. The aim of this study was to explore the relationship between GPR37 gene expression and the clinicopathological factors, patient prognosis, tumor-infiltrating immune cell signature GSEA and methylation levels in glioma.

METHODS

We explored the diagnostic value, clinical relevance, and molecular function of GPR37 in glioma using TCGA, STRING, cBioPortal, Tumor Immunity Estimation Resource (TIMER) database and MethSurv databases. Besides, the "ssGSEA" algorithm was conducted to estimate immune cells infiltration abundance, with 'ggplot2' package visualizing the results. Immunohistochemical staining of clinical samples were used to verify the speculations of bioinformatics analysis.

RESULTS

GPR37 expression was significantly higher in the glioma tissues compared to the normal brain tissues, and was linked to poor prognosis. Functional annotation of GPR37 showed enrichment of ether lipid metabolism, fat digestion and absorption, and histidine metabolism. In addition, GSEA showed that GPR37 was positively correlated to the positive regulation of macrophage derived foam cell differentiation, negative regulation of T cell receptor signaling pathway, neuroactive ligand receptor interaction, calcium signaling pathway, and negatively associated with immunoglobulin complex, immunoglobulin complex circulating, ribosome and spliceosome mediated by circulating immunoglobulin etc. TIMER2.0 and ssGSEA showed that GPR37 expression was significantly associated with the infiltration of T cells, CD8 T cell, eosinophils, macrophages, neutrophils, NK CD56dim cells, NK cells, plasmacytoid DCs (pDCs), T helper cells and T effector memory (Tem) cells. In addition, high GPR37 expression was positively correlated with increased infiltration of M2 macrophages, which in turn was associated with poor prognosis. Furthermore, GPR37 was positively correlated with various immune checkpoints (ICPs). Finally, hypomethylation of the GPR37 promoter was associated with its high expression levels and poor prognosis in glioma.

CONCLUSION

GPR37 had diagnostic and prognostic value in glioma. The possible biological mechanisms of GPR37 provide novel insights into the clinical diagnosis and treatment of glioma.

βhCG mediates immune suppression through upregulation of CD11b+ Gr1+ myeloid derived suppressor cells, CD206+ M2 macrophages, and CD4+ FOXP3+ regulatory T-cells in BRCA1 deficient breast cancers

BRCA1 mutation is reported in about 70% of all triple negative breast cancers (TNBC), while BRCA1 defect due to promoter hypermethylation is seen in about 30%-60% of sporadic breast cancers. Although PARP inhibitors and platinum-based chemotherapy are used to treat these cancers, more efficient therapeutic approaches are required to overcome the resistance to treatment. Our previous findings have reported elevated βhCG expression but not αhCG in BRCA1 deficient breast cancers. As βhCG causes immune suppression in pregnancy, this study explored the immunomodulatory effect of βhCG in BRCA1mutated/deficient TNBC. We observed that Th1, Th2, and Th17 cytokines are upregulated in the presence of βhCG in BRCA1 defective cancers. In NOD-SCID and syngeneic mouse models, βhCG increases the frequency of Myeloid-derived suppressor cells in tumour tissues and contributes to macrophage reprogramming from antitumor M1 to pro-tumour M2 phenotype. βhCG reduces the CD4+ T-cell infiltration while increasing the density of CD4+ CD25+ FOXP3+ regulatory T-cell in BRCA1 deficient tumour tissues. In contrast, xenograft tumours with βhCG knocked down TNBC cells did not show these immune suppressive effects. We have also shown that βhCG upregulates pro-tumorigenic markers arginase1(Arg1), inducible nitric oxide synthase, PD-L1/PD-1, and NFκB in BRCA1 defective tumours. Thus, for the first time, this study proves that βhCG suppresses the host antitumor immune response and contributes to tumour progression in BRCA1 deficient tumours. This study will help develop new immunotherapeutic approaches for treating BRCA1 defective TNBC by regulating βhCG.

Exosomal PD-L1 derived from head and neck squamous cell carcinoma promotes immune evasion by activating the positive feedback loop of activated regulatory T cell-M2 macrophage

The positive feedback loop of activated regulatory T cells (aTregs) and M2 macrophages (M2) play a vital role in promoting the tumor immunosuppressive microenvironment of head and neck squamous cell carcinoma (HNSCC). However, the key factors regulating the positive feedback loop remain unclear. Herein, we investigated the effect of PD-L1 carried on exosomes derived from tumor cells (TEXs) on the aTreg-M2 positive feedback loop, as well as their role in mediating immunosuppression. In our study, TEXs with or without PD-L1 (TEX-PD-L1 or TEX-PD-L1KO) were treated with CD4+CD25- T cells and M0 macrophages, and the effect on the differentiation of aTregs, M2 and the aTreg-M2 positive feedback loop was assessed. TEXs carried more PD-L1 than tumor cells and not only promoted the differentiation of aTregs and M2, but also, most importantly, enhanced the positive feedback loop of aTreg-M2, which inhibited the proliferation of CD4+CD25- T cells and in turn led to tumor immune escape. Moreover, in vivo study showed that TEX-PD-L1KO could inhibit tumor growth and significantly improve the antitumor efficacy in both the peripheral and tumor microenvironments. Collectively this study revealed the role and mechanism of TEX-PD-L1 in negative immune regulation, and targeting TEX-PD-L1 may be a new idea and strategy for immunotherapy of HNSCC.

Critical contributions of protein cargos to the functions of macrophage-derived extracellular vesicles

BACKGROUND

Macrophages are highly plastic innate immune cells that play key roles in host defense, tissue repair, and homeostasis maintenance. In response to divergent stimuli, macrophages rapidly alter their functions and manifest a wide polarization spectrum with two extremes: M1 or classical activation and M2 or alternative activation. Extracellular vesicles (EVs) secreted from differentially activated macrophages have been shown to have diverse functions, which are primarily attributed to their microRNA cargos. The role of protein cargos in these EVs remains largely unexplored. Therefore, in this study, we focused on the protein cargos in macrophage-derived EVs.

RESULTS

Naïve murine bone marrow-derived macrophages were treated with lipopolysaccharide or interlukin-4 to induce M1 or M2 macrophages, respectively. The proteins of EVs and their parental macrophages were subjected to quantitative proteomics analyses, followed by bioinformatic analyses. The enriched proteins of M1-EVs were involved in proinflammatory pathways and those of M2-EVs were associated with immunomodulation and tissue remodeling. The signature proteins of EVs shared a limited subset of the proteins of their respective progenitor macrophages, but they covered many of the typical pathways and functions of their parental cells, suggesting their respective M1-like and M2-like phenotypes and functions. Experimental examination validated that protein cargos in M1- or M2-EVs induced M1 or M2 polarization, respectively. More importantly, proteins in M1-EVs promoted viability, proliferation, and activation of T lymphocytes, whereas proteins in M2-EVs potently protected the tight junction structure and barrier integrity of epithelial cells from disruption. Intravenous administration of M2-EVs in colitis mice led to their accumulation in the colon, alleviation of colonic inflammation, promotion of M2 macrophage polarization, and improvement of gut barrier functions. Protein cargos in M2-EVs played a key role in their protective function in colitis.

CONCLUSION

This study has yielded a comprehensive unbiased dataset of protein cargos in macrophage-derived EVs, provided a systemic view of their potential functions, and highlighted the important engagement of protein cargos in the pathophysiological functions of these EVs.

The Role of M1 and M2 Myocardial Macrophages in Promoting Proliferation and Healing via Activating Epithelial-to-Mesenchymal Transition

(1) Background: The activation of sequential processes for the formation of permanent fibrotic tissue following myocardial infarction (MI) is pivotal for optimal healing of heart tissue. M1 and M2 macrophages are known to play essential roles in wound healing by the activation of cardiac fibroblasts after an episode of MI. However, the molecular and cellular mechanisms mediated by these macrophages in cellular proliferation, fibrosis, and wound healing remain unclear. (2) Methods: In the present study, we aimed to explore the mechanisms by which M1 and M2 macrophages contribute to cellular proliferation, fibrosis, and wound healing. Using both in vivo and cellular models, we examined the remodeling effects of M1 and M2 macrophages on infarcted cardiac fibroblasts and their role in promoting cardiac healing post-MI. (3) Results: Our findings indicate that M1 macrophages induce a proliferative effect on infarcted cardiac fibroblasts by exerting an anti-apoptotic effect, thereby preventing cell death. Moreover, M1 macrophages were found to activate the mechanism of epithelial-to-mesenchymal transition (EMT), resulting in wound healing and inducing the fibrotic process. The present findings suggest that M1 macrophages play a crucial role in promoting cardiac remodeling post-MI, as they activate the EMT pathway and contribute to increased collagen production and fibrotic changes. (4) Conclusions: The present study provides insights into molecular and cellular mechanisms mediated by M1 and M2 macrophages in cellular proliferation, fibrosis, and wound healing post-MI. Our findings highlight the critical role of M1 macrophages in promoting cardiac remodeling by activating the EMT pathway. Understanding these mechanisms can potentially result in the development of targeted therapies aimed at enhancing the healing process and improving outcomes following MI.

Colon-Accumulated Gold Nanoclusters Alleviate Intestinal Inflammation and Prevent Secondary Colorectal Carcinogenesis via Nrf2-Dependent Macrophage Reprogramming

Inflammatory bowel disease (IBD) is one of the main factors leading to colitis-associated colorectal cancer (CAC). Therefore, it is critical to develop an effective treatment for IBD to prevent secondary colorectal carcinogenesis. M2 macrophages play crucial roles in the resolution phase of intestinal inflammation. However, traditional drugs rarely target intestinal M2 macrophages, and they are not easily cleared. Gold nanoclusters are known for their in vivo safety and intrinsic biomedical activities. In this study, a glutathione-protected gold nanocluster is synthesized and evaluated, namely, GA. Interestingly, GA specifically accumulates in the colon during IBD. Furthermore, GA not only promotes M2 differentiation of IL-4-treated peritoneal macrophages but also reprograms macrophage polarization from M1 to M2 in a pro-inflammatory environment. Mechanistically, this regulatory effect is exerted through activating the antioxidant Nrf2 signaling pathway, but not traditional STAT6. When applied in IBD mice, we found that GA elevates M2 macrophages and alleviates IBD in an Nrf2-dependent manner, evidenced by the abolished therapeutic effect upon Nrf2 inhibitor treatment. Most importantly, GA administration significantly suppresses AOM/DSS-induced CAC, without causing obvious tissue damage, providing critical evidence for the potential application of gold nanoclusters as nanomedicine for the treatment of IBD and CAC.