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Background: Epidemiological studies associate an increase in breast cancer risk, particularly triple-negative breast cancer (TNBC), with lack of breastfeeding. This is more prevalent in African American women, with significantly lower rate of breastfeeding compared to Caucasian women. Prolonged breastfeeding leads to gradual involution (GI), whereas short-term or lack of breastfeeding leads to abrupt involution (AI) of the breast. Our previous study utilizing a murine model demonstrated precancerous changes, specifically hyperplasia, a non-obligate precursor of breast cancer in the mammary glands of AI mice. Here we investigated mechanisms during early events of AI that prompts precancerous changes in mouse mammary glands. Methods: Uniparous FVB/N mice were randomized to AI and GI on postpartum day 7 when all pups were removed from AI dams. GI dams were allowed to nurse the pups till day 31. Cell death kinetics and gene expression were assessed by TUNEL assay and qPCR respectively. Immune cell changes were investigated by flow cytometry, cytokine array and multiplex immunofluorescence. 3D-organoid cultures were used for in vitro assay of luminal progenitor cells. Results: AI results in rapid cell death, DNA repair response, and immunosuppressive myeloid cells infiltration, leading to a chronically inflamed microenvironment. GI elicits a more controlled immune response and extended cell death. At the peak of cell death, AI glands harbored more immunosuppressive myeloid-derived suppressor cells (MDSCs) and CD206 + M2-like macrophages, known to promote oncogenic events, compared to GI glands. AI glands exhibit an enrichment of CCL9-producing MDSCs and CD206 + M2-like macrophages that promote expansion of ELF5 + /ERα- luminal cells, both in vitro and in vivo. Multiplex imaging of AI glands demonstrated an increase in ELF5 + /WNT5a + luminal cells alongside a reduction in the ELF5 + /ERα + population when involution appeared histologically complete. A significantly higher number of CD206 + cells in post involution AI gland attests to a chronically inflamed state induced by AI. Conclusions: Our findings reveal significant disparities between AI and GI gland dynamics at the early phase of involution. CCL9, secreted by immune cells at the peak of cell death promotes expansion of Elf5 + /ERα- luminal progenitor cells, the putative precursors of TNBC connecting early events of AI with increased breast cancer risk. [ABSTRACT FROM AUTHOR]

Abstract Background Epidemiological studies associate an increase in breast cancer risk, particularly triple-negative breast cancer (TNBC), with lack of breastfeeding. This is more prevalent in African American women, with significantly lower rate of breastfeeding compared to Caucasian women. Prolonged breastfeeding leads to gradual involution (GI), whereas short-term or lack of breastfeeding leads to abrupt involution (AI) of the breast. Our previous study utilizing a murine model demonstrated precancerous changes, specifically hyperplasia, a non-obligate precursor of breast cancer in the mammary glands of AI mice. Here we investigated mechanisms during early events of AI that prompts precancerous changes in mouse mammary glands. Methods Uniparous FVB/N mice were randomized to AI and GI on postpartum day 7 when all pups were removed from AI dams. GI dams were allowed to nurse the pups till day 31. Cell death kinetics and gene expression were assessed by TUNEL assay and qPCR respectively. Immune cell changes were investigated by flow cytometry, cytokine array and multiplex immunofluorescence. 3D-organoid cultures were used for in vitro assay of luminal progenitor cells. Results AI results in rapid cell death, DNA repair response, and immunosuppressive myeloid cells infiltration, leading to a chronically inflamed microenvironment. GI elicits a more controlled immune response and extended cell death. At the peak of cell death, AI glands harbored more immunosuppressive myeloid-derived suppressor cells (MDSCs) and CD206 + M2-like macrophages, known to promote oncogenic events, compared to GI glands. AI glands exhibit an enrichment of CCL9-producing MDSCs and CD206 + M2-like macrophages that promote expansion of ELF5 + /ERα- luminal cells, both in vitro and in vivo. Multiplex imaging of AI glands demonstrated an increase in ELF5 + /WNT5a + luminal cells alongside a reduction in the ELF5 + /ERα + population when involution appeared histologically complete. A significantly higher number of CD206 + cells in post involution AI gland attests to a chronically inflamed state induced by AI. Conclusions Our findings reveal significant disparities between AI and GI gland dynamics at the early phase of involution. CCL9, secreted by immune cells at the peak of cell death promotes expansion of Elf5 + /ERα- luminal progenitor cells, the putative precursors of TNBC connecting early events of AI with increased breast cancer risk.

Abstract Background Rheumatoid arthritis (RA) is a chronic autoimmune disease characterized by joint inflammation, tissue damage, and fibrosis, significantly affecting the quality of life. While there are currently some effective treatments available, they often come with side effects. There is an urgent need to find new treatments that can further improve therapeutic outcomes and reduce side effects. Methods Our study investigates the role of Mesenchymal Stem Cell exosomes (MSC-exo) combined with Ginsenoside Rh2 (Rh2) in the treatment of RA. We specifically focus on how this combined strategy influences macrophage polarization and pyroptosis. This research utilized a collagen-induced rat arthritis model. Results The study findings reveal that the combination of MSC-exo combined with Rh2 can inhibit the polarization of M1 macrophages, increase the proportion of M2-like macrophages, and suppress M1-like macrophage pyroptosis via the NLRP3/Caspase11/GSDMD-N pathway. In the rat arthritis model, the combination of MSC-exo and Rh2 showed synergistic therapeutic effects. Conclusion This research contributes to a deeper understanding of RA’s pathogenesis and presents new potential targeted therapeutic interventions. The combined application of MSC-exo and Rh2 offers promising insights for future innovative strategies in RA treatment, paving the way for more effective management of this autoimmune disease.

Abstract Pazopanib (PAZ), an oral multi-tyrosine kinase inhibitor, demonstrates promising cytostatic activities against various human cancers. However, its clinical utility is limited by substantial side effects and therapeutic resistance. We developed a nanoplatform capable of delivering PAZ for enhanced anti-breast cancer therapy. Nanometer-sized PAZ@Fe-MOF, compared to free PAZ, demonstrated increased anti-tumor therapeutic activities in both syngeneic murine 4T1 and xenograft human MDA-MB-231 breast cancer models. High-throughput single-cell RNA sequencing (scRNAseq) revealed that PAZ@Fe-MOF significantly reduced pro-tumorigenic M2-like macrophage populations at tumor sites and suppressed M2-type signaling pathways, such as ATF6-TGFBR1-SMAD3, as well as chemokines including CCL17, CCL22, and CCL24. PAZ@Fe-MOF reprogramed the inhibitory immune microenvironment and curbed tumorigenicity by blocking the polarization of M2 phenotype macrophages. This platform offers a promising and new strategy for improving the cytotoxicity of PAZ against breast cancers. It provides a method to evaluate the immunological response of tumor cells to PAZ-mediated treatment.

Pazopanib (PAZ), an oral multi-tyrosine kinase inhibitor, demonstrates promising cytostatic activities against various human cancers. However, its clinical utility is limited by substantial side effects and therapeutic resistance. We developed a nanoplatform capable of delivering PAZ for enhanced anti-breast cancer therapy. Nanometer-sized PAZ@Fe-MOF, compared to free PAZ, demonstrated increased anti-tumor therapeutic activities in both syngeneic murine 4T1 and xenograft human MDA-MB-231 breast cancer models. High-throughput single-cell RNA sequencing (scRNAseq) revealed that PAZ@Fe-MOF significantly reduced pro-tumorigenic M2-like macrophage populations at tumor sites and suppressed M2-type signaling pathways, such as ATF6-TGFBR1-SMAD3, as well as chemokines including CCL17, CCL22, and CCL24. PAZ@Fe-MOF reprogramed the inhibitory immune microenvironment and curbed tumorigenicity by blocking the polarization of M2 phenotype macrophages. This platform offers a promising and new strategy for improving the cytotoxicity of PAZ against breast cancers. It provides a method to evaluate the immunological response of tumor cells to PAZ-mediated treatment. [ABSTRACT FROM AUTHOR]

Neuroblastoma (NB) is the most common and deadliest extracranial solid tumor in children. Targeting tumor-associated macrophages (TAMs) is a strategy for attenuating tumor-promoting states. The crosstalk between cancer cells and TAMs plays a pivotal role in mediating tumor progression in NB. The overexpression of Hexokinase-3 (HK3), a pivotal enzyme in glucose metabolism, has been associated with poor prognosis in NB patients. Furthermore, it correlates with the infiltration of M2-like macrophages within NB tumors, indicating its significant involvement in tumor progression. Therefore, HK3 not only directly regulates the malignant biological behaviors of tumor cells, such as proliferation, migration, and invasion, but also recruits and polarizes M2-like macrophages through the PI3K/AKT-CXCL14 axis in neuroblastoma. The secretion of lactate and histone lactylation alterations within tumor cells accompanies this interaction. Additionally, elevated expression of HK3 in M2-TAMs was found at the same time. Modulating HK3 within M2-TAMs alters the biological behavior of tumor cells, as demonstrated by our in vitro studies. This study highlights the pivotal role of HK3 in the progression of NB malignancy and its intricate regulatory network with M2-TAMs. It establishes HK3 as a promising dual-functional biomarker and therapeutic target in combating neuroblastoma. [ABSTRACT FROM AUTHOR]

Objective: Rheumatoid arthritis is an autoimmune disease characterized by synovial inflammation-driven cartilage and bone destruction, a process mainly mediated by osteoclasts. In recent years M2-like macrophages have been found to play an important role in the pathological process of RA by mediating pro-inflammatory effects, but their roles in the bone destruction of autoimmune arthritis have not been reported. Methods and Results: In this study we identified that an abundant cell population of CD45+CD11b+Gr-1-F4/80+CD206+ cells, which were normally classified as M2-like macrophages, was present in synovium of collagen-induced arthritis (CIA) mice, and these cells had the potential to differentiate into osteoclasts. These M2-like macrophages sorted from CIA synovium highly expressed RANK and could be activated by RANKL and M-CSF to acquire osteoclast markers and bone resorption function both in vitro and in vivo. Furthermore, in vitro differentiated M2 macrophages from both CIA mouse bone marrow and RA patient peripheral blood mononuclear cells were also able to differentiate into osteoclasts, confirming the general osteoclastogenesis capability of M2 subtype macrophages. Conclusion: All these results suggest that synovial F4/80+CD206+ M2-like macrophages in RA may be novel osteoclast precursors and contribute significantly to bone erosive changes seen in RA. Our studies provided new directions and targets for the diagnosis and treatment of rheumatoid arthritis. [ABSTRACT FROM AUTHOR]

Cancer patients face a high risk of tumor recurrence and metastasis after surgery. Surgical stress has been reported to be an important trigger for cancer recurrence and metastasis. Energy-based surgical devices have become the most commonly used surgical tool in recent years. However, there is a lack of studies investigating whether using energy-based surgical devices promotes the development of residual tumors. This study aimed to examine the impact of energy-based surgery on tumor growth in comparison to conventional surgery. Results indicated that energy-based surgery is more likely to promote tumor growth than conventional surgery. Further investigation revealed that the carbonized particles produced by energy-based surgical devices during tissue combustion are robust inducers, strongly inducing the polarization of M2-like macrophages in vivo and in vitro. Additionally, carbonized particles induced an immunosuppressive tumor microenvironment in vivo, promoting tumor growth similarly to energy-based surgery. These findings suggested that the production of carbonized particles during energy-based surgery contributed to the development of residual tumor cells. Therefore, it is advisable to implement measures to either eliminate or prevent the production of carbonized particles during energy-based surgery procedures. [Display omitted] • Energy-based surgery promotes peritoneal tumor growth by changing the TME compared to conventional surgery. • Carbonized particles generated by energy-based surgery induce M2 macrophage polarization and release of TGF-β and IL-10. • Carbonized particles promote residual tumor growth; avoiding their production in energy-based surgery is recommended. [ABSTRACT FROM AUTHOR]

Abstract Aims The alternatively activated macrophages have shown a cardioprotective effect in heart failure. However, the effect of M2 adoptive transfer in non-ischemic heart failure is unknown. In this study, we evaluated the efficacy of M-CSF plus IL-4 induced M2-like macrophages transplantation in doxorubicin-induced cardiotoxicity. Methods Bone marrow mononuclear cells were polarized as CCR2+CD206+ M2-like macrophages by a combination of M-CSF plus IL-4 treatment. C57BL/6 mice received a single intraperitoneal injection of doxorubicin (15 mg/kg). The treatment group were treated with M2-like macrophages (1 × 10^6 cells per mouse; i.v.) once a week for 2 weeks. After 3 weeks, we examined the percentage of resident cells and cardiac function. Furthermore, we evaluated cardiac fibrosis, cardiomyocyte apoptosis and circulating inflammatory factors. Finally, we investigated the mitochondria transfer in vitro in a direct and indirect co-culture conditions. Results Cardiac function was significantly improved in doxorubicin-induced heart failure by adoptive transfer of M2-like macrophages. Besides, M2-like macrophages treatment attenuated cardiac fibrosis and cardiomyocyte apoptosis, as well as increased the level of circulating IL-4 and Th2 response. In vitro, M2-like macrophages could transfer mitochondria to injured cardiomyocytes in a direct and indirect way. Conclusions In our study, adoptive transfer of M2-like macrophages could protect against the doxorubicin-induced cardiotoxicity, which may be partly attributed to mitochondria transfer. And M2-like macrophages transplantation could become a treatment for non-ischemic heart failure in the clinical practice. Graphical Abstract

Tumour-associated macrophages (TAMs) often promote cancer progression through immunosuppression in the tumour microenvironment (TME). However, the signalling pathways crosstalk responsible for this mechanism remain unclear. The aim of our study was to investigate whether the interaction between TAMs and colorectal cancer cells could be down-regulated by nanoparticles (NPs) loaded with retinoic acid (RA) and coated with cholesterol (CHO), in combination with an anti-PD-L1 immune checkpoint inhibitor. Tumours were evaluated by qRT-PCR and immunohistochemistry from allographic tumour growth model. In addition, human tumours were evaluated by Tissue Microarray (TMA) and immunohistochemistry. Complementary analysis of epithelial-mesenchymal transition, cell migration, and macrophage polarisation were evaluated in vitro. We showed that the IL-10R/IL-10 axis is involved in overstimulation of the STAT3 pathway as well as downregulation of the NF-κB signalling pathway, which supports a loop of immunosuppressive cytokines that induces the M2-TAM phenotype. Furthermore, our combined findings suggest that the upregulation of STAT3/NF-κB pathways crosstalk mediated by immunosuppressive cytokines, such as IL-10/PD-L1/TGF-β, via M2-TAMs in the TME, leads to immunosuppression and epithelial-mesenchymal-transition of the colorectal cancer for stimulating Vimentin, CXCL12 and CD163 in the primary tumours. Importantly, NPs holding RA and coated with CHO in combination with anti-PD-L1 were more efficient in blocking this signalling pathway. These results contribute to our understanding of the immunological mechanisms, especially the re-educating of TAMs, and provide a novel management strategy for aggressive colorectal cancers using anti-PD-L1-conjugated nanocarriers.

Objective: Rheumatoid arthritis is an autoimmune disease characterized by synovial inflammation-driven cartilage and bone destruction, a process mainly mediated by osteoclasts. In recent years M2-like macrophages have been found to play an important role in the pathological process of RA by mediating pro-inflammatory effects, but their roles in the bone destruction of autoimmune arthritis have not been reported. Methods and Results: In this study we identified that an abundant cell population of CD45+CD11b+Gr-1-F4/80+CD206+ cells, which were normally classified as M2-like macrophages, was present in synovium of collagen-induced arthritis (CIA) mice, and these cells had the potential to differentiate into osteoclasts. These M2-like macrophages sorted from CIA synovium highly expressed RANK and could be activated by RANKL and M-CSF to acquire osteoclast markers and bone resorption function both in vitro and in vivo. Furthermore, in vitro differentiated M2 macrophages from both CIA mouse bone marrow and RA patient peripheral blood mononuclear cells were also able to differentiate into osteoclasts, confirming the general osteoclastogenesis capability of M2 subtype macrophages. Conclusion: All these results suggest that synovial F4/80+CD206+ M2-like macrophages in RA may be novel osteoclast precursors and contribute significantly to bone erosive changes seen in RA. Our studies provided new directions and targets for the diagnosis and treatment of rheumatoid arthritis. [ABSTRACT FROM AUTHOR]

Yunqiang Liu,1,* Mengjun Tu,2,3,* Lingling Wang4,5 1School of Medical College, Guangdong Medical University, Zhanjiang, Guang Dong Province, 524023, People’s Republic of China; 2Eye Hospital and School of Ophthalmology and Optometry, Wenzhou Medical University, Wenzhou, Zhejiang Province, 325027, People’s Republic of China; 3National Clinical Research Center for Ocular Diseases, Wenzhou, Zhejiang Province, 325027, People’s Republic of China; 4Department of Clinical Laboratory Center of the Second Affiliated Hospital & Yu Ying Children’s Hospital of Wenzhou Medical University, Wenzhou, Zhejiang Province, 325027, People’s Republic of China; 5School of Laboratory Medicine and Life Sciences, Wenzhou Medical University, Wenzhou, Zhejiang Province, 325035, People’s Republic of China*These authors contributed equally to this workCorrespondence: Lingling Wang, Department of Clinical Laboratory Center of The Second Affiliated Hospital & Yu Ying Children’s Hospital of Wenzhou Medical University, Wenzhou, Zhejiang Province, 325027, People’s Republic of China, Tel +8618867786629, Email ll77sky@163.comPurpose: Only a few studies have reported the role of FOXS1, a transcriptional factor, in the tumor development process. In this article, we investigate the function of FOXS1 in distinct neoplastic development and the tumor immune microenvironment (TIME).Patients and Methods: The latent roles of FOXS1 in various tumors were prospected based on TCGA, GTEx, CCLE, GEPIA2, cBioPortal, TIMER, ImmuCellAI databases, GSVA datasets, GSEA datasets, and R packages. The expression difference, gene alteration, clinical characteristics, prognostic values, biological mechanism, potential pathways, tumor microenvironment, and immune cell infiltration related to FOXS1 were appraised.Results: FOXS1 was strongly expressed in pan-cancer, and this gene was associated with low survival rates. FOXS1 was linked to many pathways that are cancer-promoting and immune-related. The expression of this transcriptional factor in cancers was positively related to immune cell infiltration, especially M2-like macrophages and Treg cells. In addition to that, FOXS1 demonstrated a positive relationship with many immune-suppression genes, such as TGFB1 and ARORA2A.Conclusion: Our study identified an oncogenic effect of FOXS1, which may play a vital role as a prognosticative biological marker in pan-cancer. Exorbitant expression of FOXS1 is associated with high TAMs and Treg cells infiltration. These cells have an immunosuppressive function and promote the development of the immunosuppressive tumor microenvironment. The research of FOXS1 provided a potential drug target for tumor immunotherapy.Keywords: FOXS1, pan-cancer, biological marker, M2-like macrophages, Treg cells, immunosuppressive microenvironment

Background: Tumor-associated macrophages (TAMs) are one of the most abundant immune cells in the pancreatic cancer stroma and are related to the poor prognosis of pancreatic ductal adenocarcinoma (PDAC) patients. Therefore, targeting tumor-associated macrophages is a possible strategy for the treatment of pancreatic cancer. Purpose: We would like to investigate the role of sphingomyelin synthase 2 (SMS2) and the effect of the synthase 2 selective inhibitor YE2 in TAMs and the pancreatic tumor microenvironment. In addition, we also would like to investigate the mechanism by which YE2 attenuates macrophage M2 polarization. Methods: YE2 was utilized to treat macrophages (in vitro) and mice (in vivo). Western blotting and real-time PCR were used to detect the protein levels and mRNA levels of macrophage M2 polarization markers and their downstream signaling pathways. Sphingomyelin synthase 2 gene knockout (KO) mice and their controls were used to establish a PANC-02 orthotopic pancreatic cancer model, and immune cell infiltration in the tumor tissue was analyzed by immunohistochemistry (IHC).Results: We found that sphingomyelin synthase 2 mRNA expression is positively correlated with tumor-associated macrophages, the immunosuppressive microenvironment, and poor prognosis in pancreatic ductal adenocarcinoma patients. Sphingomyelin synthase 2 deficiency was confirmed to have an inhibitory effect on the growth of orthotopic PANC-02 tumors in vivo. The deficiency not only reduced the infiltration of tumor-associated macrophages but also regulated other immune components in the tumor microenvironment. In tissue culture, YE2 inhibited M2 polarization in both bone marrow-derived macrophages (BMDMs) and THP-1 macrophages and eliminated the protumor effect of M2 macrophages. In the mouse model, YE2 treatment reduced the infiltration of TAMs and regulated other immune components in the tumor microenvironment, slowing the progression of PANC-02 tumors. In terms of mechanism, we found that the inhibition of sphingomyelin synthase 2 could downregulate the expression of IL4Rα and CSF1R, thereby attenuating M2 polarization. Conclusion: The sphingomyelin synthase 2 inhibitor YE2 or sphingomyelin synthase 2 deficiency can prevent macrophage M2 polarization in pancreatic cancer, and sphingomyelin synthase 2 could be a new potential target for the treatment of pancreatic cancer. [ABSTRACT FROM AUTHOR]

Tumor‐infiltrating monocytes can mature into Macrophages that support tumor survival or that display antitumor properties. To explore mechanisms steering Macrophage maturation, we assessed the effects of supernatants from squamous cell carcinoma cell lines (FaDu and SCC) on monocyte‐derived Macrophage maturation. Purified monocytes were incubated in medium or medium supplemented with supernatants from FaDu and SCC9 or the leukemia monocytic cell line, THP‐1. Macrophages were examined for markers of maturation (CD14, CD68), activation (HLA‐DR, CD86, IL15R), scavenger receptor (CD36), toll‐like receptor (TLR4), M2 marker (CD206), immune checkpoint (PD‐L1), and intracellular chemokine expression (IP‐10). Compared to other conditions, cells incubated with FaDu or SCC9 supernatants displayed enhanced survival, down‐regulation of cell surface HLA‐DR, CD86, IL‐15R, CD36, and intracellular IP‐10 expression, and increased cell surface PD‐L1, CD14, and CD206 expression. Despite expressing TLR4 and CD14, Macrophages matured in tumor supernatants failed to respond to stimulation with the canonical TLR4 agonist, LPS. These changes were accompanied by a decrease in intracellular phospho‐p38 expression in tumor supernatant conditioned Macrophages. Depletion of fatty acids from tumor supernatants or treatment of cell cultures with an inhibitor of fatty acid oxidation, Etomoxir, reversed a number of these phenotypic changes induced by tumor supernatants. Additionally, Macrophages incubated with either palmitic acid or oleic acid developed similar phenotypes as cells incubated in tumor supernatants. Together, these data suggest that fatty acids derived from tumor cells can mediate the maturation of Macrophages into a cell type with limited pro‐inflammatory characteristics. [ABSTRACT FROM AUTHOR]

Osteosarcoma is the most prevalent bone cancer, and chemotherapy is still an indispensable treatment in its clinical practice. Cisplatin (CDDP) has become the most commonly used agent for osteosarcoma, although the outcomes of CDDP chemotherapy remain unsatisfactory because of frequent resistance. Here, we report on a promising combination therapy where curcumol, a bioactive sesquiterpenoid, enhanced CDDP-induced apoptosis to eradicate osteosarcoma cells, and revealed that M2-like macrophages might be the underlying associated mechanisms. First, we observed that curcumol enhanced the CDDP-mediated inhibition of cell proliferation and augmented the apoptosis in osteosarcoma cell lines. Curcumol contributed to preventing the migration of osteosarcoma cells when combined with CDDP. Moreover, this drug combination showed more potent tumor-growth suppression in the orthotopic transplantation of osteosarcoma K7M2 WT cells. We then estimated chemotherapy-associated drug-resistant genes, including ABCB1, ABCC1 and ABCG2, and found that curcumol significantly reversed the mRNA levels of CDDP-induced ABCB1, ABCC1 and ABCG2 genes in the tumor tissue. Moreover, M2-like macrophages were enriched in osteosarcoma tissues, and were largely decreased after curcumol and CDDP treatment. Taken together, these findings suggest that curcumol inhibits the polarization of M2-like macrophages and could be a promising combination strategy to synergize with CDDP in the osteosarcoma. [ABSTRACT FROM AUTHOR]

One of the problems of modern medical science is cardiovascular pathology caused by atherosclerotic vascular lesions in patients with autoimmune rheumatic diseases (ARDs). The similarity between the mechanisms of the immunopathogenesis of ARD and chronic low-grade inflammation in atherosclerosis draws attention. According to modern concepts, chronic inflammation associated with uncontrolled activation of both innate and acquired immunity plays a fundamental role in all stages of ARDs and atherosclerotic processes. Macrophage monocytes play an important role among the numerous immune cells and mediators involved in the immunopathogenesis of both ARDs and atherosclerosis. An imbalance between M1-like and M2-like macrophages is considered one of the causes of ARDs. The study of a key pathogenetic factor in the development of autoimmune and atherosclerotic inflammation-activated monocyte/macrophages will deepen the knowledge of chronic inflammation pathogenesis. [ABSTRACT FROM AUTHOR]

The host immunologic response to a specific material is a critical aspect when considering it for clinical implementation. Collagen and gelatin extracted from marine sources have been proposed as biomaterials for tissue engineering applications, but there is a lack of information in the literature about their immunogenicity. In this work, we evaluated the immune response to collagen and/or gelatin from blue shark and codfish, previously extracted and characterized. After endotoxin evaluation, bone marrow-derived macrophages were exposed to the materials and a panel of pro- and anti-inflammatory cytokines were evaluated both for protein quantification and gene expression. Then, the impact of those materials in the host was evaluated through peritoneal injection in C57BL/6 mice. The results suggested shark collagen as the less immunogenic material, inducing low expression of pro-inflammatory cytokines as well as inducible nitric oxide synthase (encoded by Nos2) and high expression of Arginase 1 (encoded by Arg1). Although shark gelatin appeared to be the material with higher pro-inflammatory expression, it also presents a high expression of IL-10 (anti-inflammatory cytokine) and Arginase (both markers for M2-like macrophages). When injected in the peritoneal cavity of mice, our materials demonstrated a transient recruitment of neutrophil, being almost non-existent after 24 hours of injection. Based on these findings, the studied collagenous materials can be considered interesting biomaterial candidates for regenerative medicine as they may induce an activation of the M2-like macrophage population, which is involved in suppressing the inflammatory processes promoting tissue remodeling. Marine-origin biomaterials are emerging in the biomedical arena, namely the ones based in marine-derived collagen/gelatin proposed as cell templates for tissue regeneration. Nevertheless, although the major cause of implant rejection in clinical practice is the host's negative immune response, there is a lack of information in the literature about the immunological impact of these marine collagenous materials. This work aims to contribute with knowledge about the immunologic response to collagen/gelatin extracted from blue shark and codfish skins. The results demonstrated that despite some differences observed, all the materials can induce a macrophage phenotype related with anti-inflammation resolution and then act as immuno-modulators and anti-inflammatory inducible materials. [Display omitted] [ABSTRACT FROM AUTHOR]

Systemic sclerosis (SSc) is a challenging autoimmune disease characterized by progressive fibrosis affecting the skin and internal organs. Despite the known infiltration of macrophages and neutrophils, their precise contributions to SSc pathogenesis remain elusive. In this study, we elucidated that CD206 hi MHCII lo M2-like macrophages constitute the predominant pathogenic immune cell population in the fibrotic skin of a bleomycin-induced SSc mouse model. These cells emerged as pivotal contributors to the profibrotic response by orchestrating the production of TGF-β1 through a MerTK signaling-dependent manner. Notably, we observed that neutrophil infiltration was a prerequisite for accumulation of M2-like macrophages. Strategies such as neutrophil depletion or inhibition of CXCR1/2 were proven effective in reducing M2-like macrophages, subsequently mitigating SSc progression. Detailed investigations revealed that in fibrotic skin, neutrophil-released neutrophil extracellular traps were responsible for the differentiation of M2-like macrophages. Our findings illuminate the significant involvement of the neutrophil-macrophage-fibrosis axis in SSc pathogenesis, offering critical information for the development of potential therapeutic strategies., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

IntroductionWe previously reported a specific defect of rheumatoid arthritis (RA) monocyte polarization to anti-inflammatory M2-like macrophages related to increased miR-155 expression in all RA patients except those receiving adalimumab (ADA). In this longitudinal study, we examined whether different tumor necrosis factor inhibitors were able to restore monocyte polarization to M2-like macrophages and their effect on the transcriptomic signature.MethodsM2-like polarization induced by human serum AB was studied in 7 healthy donors and 20 RA patients included in the ABIRA cohort before and 3 months after starting ADA or etanercept (ETA). The differential gene expression of M2- and M1-related transcripts was studied in macrophage-derived monocytes after differentiation.ResultsAt baseline, RA monocytes showed a defect of polarization to M2-like macrophages as compared with healthy donor monocytes, which was negatively correlated with disease activity. M2-like polarization from circulating monocytes was restored only with ADA and not ETA treatment. The transcriptomic signature demonstrated downregulation of M2-related transcripts and upregulation of M1-related transcripts in active RA. In patients receiving ADA, the transcriptomic signature of M2-related transcripts was restored.ConclusionThis longitudinal study demonstrates that ADA but not ETA is able to restore the M2-like polarization of monocytes that is defective in RA.

Introduction: We previously reported a specific defect of rheumatoid arthritis (RA) monocyte polarization to anti-inflammatory M2-like macrophages related to increased miR-155 expression in all RA patients except those receiving adalimumab (ADA). In this longitudinal study, we examined whether different tumor necrosis factor inhibitors were able to restore monocyte polarization to M2-like macrophages and their effect on the transcriptomic signature. Methods: M2-like polarization induced by human serum AB was studied in 7 healthy donors and 20 RA patients included in the ABIRA cohort before and 3 months after starting ADA or etanercept (ETA). The differential gene expression of M2- and M1-related transcripts was studied in macrophage-derived monocytes after differentiation. Results: At baseline, RA monocytes showed a defect of polarization to M2-like macrophages as compared with healthy donor monocytes, which was negatively correlated with disease activity. M2-like polarization from circulating monocytes was restored only with ADA and not ETA treatment. The transcriptomic signature demonstrated downregulation of M2-related transcripts and upregulation of M1-related transcripts in active RA. In patients receiving ADA, the transcriptomic signature of M2-related transcripts was restored. Conclusion: This longitudinal study demonstrates that ADA but not ETA is able to restore the M2-like polarization of monocytes that is defective in RA. [ABSTRACT FROM AUTHOR]

Abstract Adipose tissue (AT) is composed not only of adipocytes, but also of macrophages, endothelial cells and preadipocytes. Macrophages are an important component of AT, and are involved in tissue homeostasis, tissue repair and fibrosis. AT‐resident macrophages are categorized into two subtypes, the M1‐like and M2‐like macrophages. M2‐like macrophages are reported to play anti‐inflammatory roles, and to be involved in clearing and removal of dying/dead adipocytes, and recruiting adipocyte progenitors (APs). M2‐like macrophages are also reported to be involved in the promotion of fibrosis in a transforming growth factor‐β‐dependent manner. However, the precise roles of M2‐like macrophages in the AT have not yet been clearly delineated. Recently, we generated genetically engineered transgenic mice in which CD206+ M2‐like macrophages can be conditionally depleted. Unexpectedly, we found that the depletion of CD206+ M2‐like macrophages resulted in the enhanced generation of smaller adipocytes, improved insulin sensitivity and proliferation of APs. We further clarified that the CD206+ M2‐like macrophages directly interact with the APs to regulate their growth/differentiation and adipogenesis, thereby controlling adiposity and systemic insulin sensitivity. In the present review, we discuss how CD206+ M2‐like macrophages provide a niche for APs and maintain glucose homeostasis.

Acute Myeloid Leukaemia (AML) is a commonly occurring severe haematological malignancy, with most patients exhibiting sub-optimal clinical outcomes. Therapy resistance significantly contributes towards failure of traditional and targeted treatments, disease relapse and mortality in AML patients. The mechanisms driving therapy resistance in AML are not fully understood, and approaches to overcome therapy resistance are important for curative therapies. To date, most studies have focused on therapy resistant mechanisms inherent to leukaemic cells (e.g., TP53 mutations), overlooking to some extent, acquired mechanisms of resistance through extrinsic processes. In the bone marrow microenvironment (BMME), leukaemic cells interact with the surrounding bone resident cells, driving acquired therapy resistance in AML. Growing evidence suggests that macrophages, highly plastic immune cells present in the BMME, play a role in the pathophysiology of AML. Leukaemia-supporting macrophage subsets (CD163+CD206+) are elevated in preclinical in vivo models of AML and AML patients. However, the relationship between macrophages and therapy resistance in AML warrants further investigation. In this review, we correlate the potential links between macrophages, the development of therapy resistance, and patient outcomes in AML. We specifically focus on macrophage reprogramming by AML cells, macrophage-driven activation of anti-cell death pathways in AML cells, and the association between macrophage phenotypes and clinical outcomes in AML, including their potential prognostic value. Lastly, we discuss therapeutic targeting of macrophages, as a strategy to circumvent therapy resistance in AML, and discuss how emerging genomic and proteomic-based approaches can be utilised to address existing challenges in this research field.

Background and Purpose: Inflammation associated with the tumour microenvironment (TME) is critical for cancer development, and immunotherapeutic strategies modulating the immune response in cancer have been crucial. In this study, a methotrexate-loaded (MTX) poly(lactic-co-glycolic acid)-based (PLGA) drug nanocarrier covered with polyethyleneimine (Pei) and hyaluronic acid (HA) was developed and combined with an PD-L1 antibody to investigate anti-cancer and immunomodulatory effects in breast cancer TME.Experimental Approach: Naked or HA-coated PeiPLGA-MTX nanoparticles (NPs) were assessed on 4T1 breast cancer cells grown in culture and in a mouse model of orthotopic tumour growth. Tumours were evaluated by qRT-PCR and immunohistochemistry. The cell death profile and cell migration were analysed in vitro in 4T1 cells. Polarization of murine macrophages (RAW cells) was also carried out.Key Results: Naked or HA-coated PeiPLGA-MTX NPs used alone or combined with PD-L1 antibody modified the tumourigenic course by TME immunomodulation, leading to reduction of primary tumour size and metastases. STAT3 and NF-κB were the major genes downregulated by NPs. In tumor-associated macrophages (TAM) such regulation switched M2 phenotype (CD163) towards M1 (CD68) and reduced levels of IL-10, TGF-β and CCL22. Moreover, malignant cells showed overexpression of FADD, APAF-1, caspase-3 and E-cadherin, and decreased expression of Bcl-2, MDR-1, survivin, vimentin, CXCR4 and PD-L1 after treatment with NPs.Conclusion and Implications: NPs-mediated STAT3/NF-κB signalling axis suppression disrupted crosstalk between immune and malignant cells, reducing immunosuppression and critical pro-tumour events. These findings provide a promising therapeutic approach capable of guiding the immune TME to suppress the development of breast cancer. [ABSTRACT FROM AUTHOR]

Abstract Background Although impaired myeloid-derived suppressor cells (MDSCs) recently have been studied in immune thrombocytopenia (ITP), another myeloid-derived cell population signified as M2 macrophages has not been investigated properly in ITP patients. In the present study, we intended to determine the features of circulating M2-like macrophages, to examine its relationship with MDSCs, and to explore their prognostic values in ITP. Methods Peripheral blood mononuclear cells from healthy controls and primary ITP patients were isolated to test the circulating M2-like macrophages and MDSCs. The circulating M2-like macrophage population defined as CD68+CD163+ and circulating MDSC population as CD11b+CD33+HLA-DR− were determined by flow cytometry. Plasma inflammatory cytokines were measured by multiplex ELISA. Results The percentages of MDSCs were found to be expanded in newly diagnosed patients of ITP, especially among those of the complete response (CR) group (p

Peripheral nerve injury typically leads to chronic inflammation through recruitment of immune cells, which may induce neuropathic pain. We previously reported that M1-like macrophages at sites of peripheral nerve injury induced neuropathic pain; however, the involvement of other immune cells (e.g. M2-like macrophages) in the progression of neuropathic pain remains unclear. In addition, the immune responses that occur at sites of nerve injury have not been well characterized. In this study, we show that M2-like macrophages accumulate in injured nerves to participate in the clearance of dead or dying cells (i.e., efferocytosis). Because MerTK (a receptor of dead or dying cells) levels on the surface of macrophages are limited, it seems to induce the insufficient of efferocytosis, such that the levels of dead or dying cells cannot be controlled in injured nerves. Given that efferocytosis is pivotal for resolution of inflammation, our data suggest that insufficient efferocytosis is a contributing factor in the development of chronic inflammation in injured nerves. • M2-like macrophages accumulate at sites of peripheral nerve injury. • M2-like macrophages participate in clearance of dead or dying cells in injured nerves. • MerTK levels on the macrophage surface are limited due to post-transcriptional regulation. • Dead or dying cells increase in number, implying the insufficient clearance from injured nerves. [ABSTRACT FROM AUTHOR]

• The diabetes-induced oxidative stress affects interstitial cells of Cajal (ICC), nitrergic neurons and M2-like macrophages. • Quercetin-loaded microcapsules (100 mg kg−1) aggravated the diabetic condition with toxic activities to the healthy animals. • Quercetin-loaded microcapsules (10 mg kg−1) displayed desirable and protective effects on diabetic and healthy rats. Given the well-known antioxidant and neuroprotective properties of quercetin, the aim of this work was to evaluate the effects of quercetin stabilized by microencapsulation at two doses (10 mg kg−1 and 100 mg kg−1) on the oxidative/antioxidant status, number and morphological features of ICC, nitrergic neurons and M2-like macrophages in jejunum of diabetic rats. The rats were randomly distributed into six groups: normoglycemic control (N), diabetic control (D) and either normoglycemic or diabetic groups treated with quercetin-loaded microcapsules at a dose of 10 mg kg−1 (NQ10 and DQ10, respectively) or 100 mg kg−1 (NQ100 and DQ100, respectively). After 60 days, the jejunum was collected. Whole mounts were immunostained for Ano1, nNOS and CD206, and oxidative stress levels and total antioxidant capacity of the jejunum were measured. Diabetes led to a loss of ICC and nitrergic neurons, but increased numbers of M2-like macrophages and elevated levels of oxidative stress were seen in diabetic animals. High-dose administration of quercetin (100 mg kg−1) further aggravated the diabetic condition (DQ100) but this treatment resulted in harmful effects on healthy rats (NQ100), pointing to a pro-oxidant activity. However, low-dose administration of quercetin (10 mg kg−1) gave rise to antioxidant and protective effects on ICC, nNOS, macrophages and oxidative/antioxidant status in DQ100, but NQ100 displayed infrequent negative outcomes in normoglycemic animals. Microencapsulation of the quercetin may become promising alternatives to reduce diabetes-induced oxidative stress but antioxidant therapies should be careful used under healthy status to avoid toxic effects. [ABSTRACT FROM AUTHOR]

Triple-negative breast cancer (TNBC) is the most aggressive subtype of breast cancers and is not eligible for hormone and anti-HER2 therapies. Identifying therapeutic targets and associated biomarkers in TNBC is a clinical challenge to improve patients’ outcome and management. High infiltration of CD206+ M2-like macrophages in the tumor microenvironment (TME) indicates poor prognosis and survival in TNBC patients. As we previously showed that membrane expression of GRP94, an endoplasmic reticulum chaperone, was associated with the anti-inflammatory profile of human PBMC-derived M2 macrophages, we hypothesized that intra-tumoral CD206+ M2 macrophages expressing GRP94 may represent innovative targets in TNBC for theranostic purposes. We demonstrate in a preclinical model of 4T1 breast tumor-bearing BALB/c mice that (i) CD206-expressing M2-like macrophages in the TME of TNBC can be specifically detected and quantified using in vivo SPECT imaging with 99mTc-Tilmanocept, and (ii) the inhibition of GRP94 with the chemical inhibitor PU-WS13 induces a decrease in CD206-expressing M2-like macrophages in TME. This result correlated with reduced tumor growth and collagen content, as well as an increase in CD8+ cells in the TME. 99mTc-Tilmanocept SPECT imaging might represent an innovative non-invasive strategy to quantify CD206+ tumor-associated macrophages as a biomarker of anti-GRP94 therapy efficacy and TNBC tumor aggressiveness.

Adipose tissue (AT) is composed not only of adipocytes, but also of macrophages, endothelial cells and preadipocytes. Macrophages are an important component of AT, and are involved in tissue homeostasis, tissue repair and fibrosis. AT‐resident macrophages are categorized into two subtypes, the M1‐like and M2‐like macrophages. M2‐like macrophages are reported to play anti‐inflammatory roles, and to be involved in clearing and removal of dying/dead adipocytes, and recruiting adipocyte progenitors (APs). M2‐like macrophages are also reported to be involved in the promotion of fibrosis in a transforming growth factor‐β‐dependent manner. However, the precise roles of M2‐like macrophages in the AT have not yet been clearly delineated. Recently, we generated genetically engineered transgenic mice in which CD206+ M2‐like macrophages can be conditionally depleted. Unexpectedly, we found that the depletion of CD206+ M2‐like macrophages resulted in the enhanced generation of smaller adipocytes, improved insulin sensitivity and proliferation of APs. We further clarified that the CD206+ M2‐like macrophages directly interact with the APs to regulate their growth/differentiation and adipogenesis, thereby controlling adiposity and systemic insulin sensitivity. In the present review, we discuss how CD206+ M2‐like macrophages provide a niche for APs and maintain glucose homeostasis. [ABSTRACT FROM AUTHOR]

The safety and effectiveness of in vitro generated M2-like macrophages for treatment of patients with ischemic and hemorrhagic brain stroke in reparative and residual periods has been evaluated. A single endolumbar administration of autologous M2-like macrophages in the mean dose of 17,9 х 106 cells was conducted in 13 patients with ischemic (n = 10) and hemorrhagic (n = 3) brain stroke. At 6 months after cells administration all the patients had clinical Improvement. NIHS score decreased from 8,6 ± 1,06 to 4,4 ± 0.55 (p = 0,0008), several patients showed the decrease of sensitiveness impairments, improvement of cognitive functions and enhanced quality of life. Thus, we demonstrated an ability of generation M2-like macrophages from patients with brain stroke. Endolumbar administration of these cells was safe andi didn't cause severe adverse effects and complications andi — in preliminary data — improvedi motional and cognitive functions.

[Display omitted] • silibinin-phospholipid remarkably alleviated the acute hepatic damage. • SPC inhibits necroptosis-S100A9-necroinflammation through activating M2-like macrophages. • SPC up-regulates miR-223-3p and further promotes M2-like activation of macrophages. Silibinin-phospholipid complex (SPC) has been utilized to treat acute liver injury clinically. Nevertheless, the hepatoprotective mechanism of SPC remains to be further dissected in response to new insights into the pathogenesis of acute liver injury. Very recently, we have documented, for the first time, that M2-like macrophages exert the hepatoprotection against acute insult through inhibiting necroptosis-S100A9-necroinflammation. In the present work, we integrated this new finding into the mechanism of action of SPC, and attempted to dissect the hepatoprotective mechanism of SPC from this new perspective. SPC and corresponding controls were administered intragastrically into control mice subjected to d -GalN/LPS challenge. The hepatic damage was assessed, and the expression of necroptosis-S100A9-necroinflammation signaling molecules was detected. The correlation between SPC and macrophage activation was investigated. The expression of miR-223-3p and its regulation on macrophage activation were analyzed. The targeted inhibitory effects of miR-223-3p on necroptosis and necroinflammation signaling molecules were confirmed. SPC alleviated remarkably the hepatic damage triggered by d -GalN/LPS. The administration of SPC inhibited the expression of necroptosis-S100A9-necroinflammation signaling molecules. The levels of M2-like macrophage markers were increased significantly in SPC-treated mice or macrophages. miR-223-3p expression was enhanced in SPC-treated mice. miR-223-3p transfer led to up-regulated expression of M2-like macrophage markers. miR-223-3p directly targeted 3′ UTR of RIPK3 and NLRP3, and the expression of necroptosis and necroinflammation signaling molecules was inhibited in miR-223-3p-transferred hepatocytes and macrophages. SPC alleviates acute liver injury through up-regulating the expression of miR-223-3p. MiR-223-3p further promotes M2-like macrophage activation and the targeted inhibition of necroptosis and necroinflammation. Our findings provide novel insight into the hepatoprotective mechanism of SPC against acute liver injury. [ABSTRACT FROM AUTHOR]

Triple-negative breast cancer (TNBC) is the most aggressive subtype of breast cancers and is not eligible for hormone and anti-HER2 therapies. Identifying therapeutic targets and associated biomarkers in TNBC is a clinical challenge to improve patients' outcome and management. High infiltration of CD206+ M2-like macrophages in the tumor microenvironment (TME) indicates poor prognosis and survival in TNBC patients. As we previously showed that membrane expression of GRP94, an endoplasmic reticulum chaperone, was associated with the anti-inflammatory profile of human PBMC-derived M2 macrophages, we hypothesized that intra-tumoral CD206+ M2 macrophages expressing GRP94 may represent innovative targets in TNBC for theranostic purposes. We demonstrate in a preclinical model of 4T1 breast tumor-bearing BALB/c mice that (i) CD206-expressing M2-like macrophages in the TME of TNBC can be specifically detected and quantified using in vivo SPECT imaging with 99mTc-Tilmanocept, and (ii) the inhibition of GRP94 with the chemical inhibitor PU-WS13 induces a decrease in CD206-expressing M2-like macrophages in TME. This result correlated with reduced tumor growth and collagen content, as well as an increase in CD8+ cells in the TME. 99mTc-Tilmanocept SPECT imaging might represent an innovative non-invasive strategy to quantify CD206+ tumor-associated macrophages as a biomarker of anti-GRP94 therapy efficacy and TNBC tumor aggressiveness. [ABSTRACT FROM AUTHOR]

In this study, we noninvasively assessed whether M2-like macrophages accelerate the progression of ovarian cancer by performing molecular imaging of ovarian cancer cells expressing enhanced firefly luciferase (Effluc) in living mice. First, murine ovarian cancer ID8 cells expressing Effluc (ID8/Effluc cells) were established by retroviral infection. Subsequently, macrophages were isolated from the peritoneal exudate of mice injected with thioglycollate medium and differentiated into M2-like macrophages by adding interleukin 4. To characterize these M2-like macrophages, F4/80 and cluster of differentiation 206 expression levels were determined. Then, the M2-like macrophages were co-cultured with the ID8/Effluc cells and bioluminescence imaging (BLI) of signals from the ID8/Effluc cells was completed. Additionally, migration and wound healing were assessed to evaluate the effects of conditioned medium (CM) from M2-like macrophages on ID8/Effluc cell motility. In the in vivo study, mice were first given either liposome–phosphate-buffered saline or liposome-clodronate (lipo-clodronate). After 24 h, ID8/Effluc cells were intraperitoneally injected into the mice and BLI was completed at the designed time points. Next, histological analysis was conducted to characterize the infiltrated tumor. Flow cytometric analysis revealed high levels of CD206 expression in the differentiated M2-like macrophages. Meanwhile, ID8/Effluc cells co-cultured with these M2-like macrophages proliferated rapidly in an M2-like macrophage, number-dependent manner. The migration of the ID8/Effluc cells was also increased by the application of CM from M2-like macrophages. In vivo BLI revealed that the growth rate of intraperitoneally injected ovarian cancer cells was inhibited following macrophage depletion by treatment with lipo-clodronate. M2-like macrophages accelerated the progression of ovarian cancer, suggesting they are a new therapeutic target for ovarian cancer and that ovarian cancer could be managed by altering the nature of communication between ovarian cancer and macrophages. [ABSTRACT FROM AUTHOR]

The antitumor efficacy of tumor vaccines is often limited by weak T cell responses and poor activated T cells infiltration. Herein, we reported a novel synergistic strategy to simultaneously overcome these two obstacles to realize enhanced tumor elimination. To induce the robust T cell responses, we designed a minimalist tumor nanovaccine based on stepwise electrostatic interactions. The dual-functional delivery system PEI/CaCO 3 (polyethylenimine coated CaCO 3), could not only act as a vaccine carrier that absorbed antigen ovalbumin (OVA) and adjuvant unmethylated cytosine-phosphate-guanine (CpG) with high efficiency, but also work as an underlying adjuvant to activate bone marrow-derived dendritic cells (BMDCs). Therefore, the formed PEI/CaCO 3 /OVA/CpG vaccines (NVs) realized the significant enhancement of both the BMDCs activation and the specific responses of T cells in vivo. In addition, to enhance the infiltration of activated T cells in the tumor sites, the Spam1 gene, which could express hyaluronidase (HAase), was explored using PEI as the gene carrier shielded with aldehyde modified polyethylene glycol (CHO-PEG-CHO) through pH responsive Schiff base bonds. PEG/PEI/ p Spam1 (p Spam1@NPs) could achieve a high HAase expression in the tumor sites to further degrade the tumor extracellular matrix, thus promoting the infiltration of immune cells. Besides, the degradation of extracellular matrix increased blood perfusion and relieved the tumor hypoxia to modulate the immune-suppressive microenvironment. Highly enhanced antitumor efficiency and tumor re-challenge prevention were achieved by combined NVs with p Spam1@NPs in B16-OVA bearing mice. The facile synergistic strategy we presented here is expected to be further used for personalized immunotherapy in the future. [ABSTRACT FROM AUTHOR]

Copper is one of the essential micronutrients, and copper-containing enzymes contribute to crucial functions in the body. Lysyl oxidase is a copper-containing enzyme that remodels the extracellular matrix by cross-linking collagen and elastin. The overexpression of lysyl oxidase was recently shown to promote tumor metastasis. M2-like macrophages were also found to significantly accumulate in the tumor microenvironment, and correlated with a poor patient's outcome. We speculate that M2-like macrophages promote tumor progression via lysyl oxidase expression. Epigenetics, a mitotically heritable change in gene expression without any change in DNA sequencing, is also associated with tumor progression. However, the relationship between lysyl oxidase expression in M2-like macrophages and epigenetics remains unclear. Lysyl oxidase expression was significantly induced in human leukemic THP-1 cell-derived M2-like macrophages. Furthermore, the level of histone H3 tri-methylation at lysine 27 was decreased, and a pre-treatment with a H3K27 demethylase inhibitor notably suppressed lysyl oxidase expression in M2-like macrophages. Lysyl oxidase derived from M2-like macrophages also enhanced breast cancer cell migration, and this was suppressed by a H3K27 demethylase inhibitor. The present results suggest the mechanism of lysyl oxidase expression in M2-like macrophages as an aspect of epigenetics, particularly histone methylation., Competing Interests: No potential conflicts of interest were disclosed., (Copyright © 2020 JCBNCopyright © 2020 JCBN.)

Background: Although impaired myeloid-derived suppressor cells (MDSCs) recently have been studied in immune thrombocytopenia (ITP), another myeloid-derived cell population signified as M2 macrophages has not been investigated properly in ITP patients. In the present study, we intended to determine the features of circulating M2-like macrophages, to examine its relationship with MDSCs, and to explore their prognostic values in ITP.Methods: Peripheral blood mononuclear cells from healthy controls and primary ITP patients were isolated to test the circulating M2-like macrophages and MDSCs. The circulating M2-like macrophage population defined as CD68+CD163+ and circulating MDSC population as CD11b+CD33+HLA-DR- were determined by flow cytometry. Plasma inflammatory cytokines were measured by multiplex ELISA.Results: The percentages of MDSCs were found to be expanded in newly diagnosed patients of ITP, especially among those of the complete response (CR) group (p < 0.0001). Positive linear correlation was verified between percentages of M2-like macrophages and MDSCs. The same correlation was also determined in the CR group. After treatment, the percentages of M2-like macrophages and MDSCs were both increased significantly in CR group, while those patients among the PR + NR group manifested a significant numeric decrease of MDSCs but only a moderate decrease in M2-like macrophages. MIP-1α/CCL3 was negatively correlated with M2-like macrophages while MCP-1 possessed a positive correlation with M2-like macrophages, eotaxin-1/CCL11 was negatively correlated with MDSCs and interleukin-1β (IL-1β) was found to be negatively correlated with both M2-like macrophages and MDSCs.Conclusions: The present findings indicated critical roles of both circulating M2-like macrophages and MDSCs in ITP. The positive correlation between them might be related to inflammatory factors-mediated bidirectional interactions or partially due to their similar background patterns during differentiation. MIP-1α/CCL3, MCP-1, eotaxin-1/CCL11 and IL-1β might play a critical role in the expansion of both M2 macrophages and MDSCs population in ITP patients, which deserves further investigation. [ABSTRACT FROM AUTHOR]

Myeloid cells play a central role in the context of viral eradication, yet precisely how these cells differentiate throughout the course of acute infections is poorly understood. In this study, we have developed a novel quantitative temporal in vivo proteomics (QTiPs) platform to capture proteomic signatures of temporally transitioning virus-driven myeloid cells directly in situ, thus taking into consideration host-virus interactions throughout the course of an infection. QTiPs, in combination with phenotypic, functional, and metabolic analyses, elucidated a pivotal role for inflammatory CD11b + , Ly6G - , Ly6C high-low cells in antiviral immune response and viral clearance. Most importantly, the time-resolved QTiPs data set showed the transition of CD11b + , Ly6G - , Ly6C high-low cells into M2-like macrophages, which displayed increased antigen-presentation capacities and bioenergetic demands late in infection. We elucidated the pivotal role of myeloid cells in virus clearance and show how these cells phenotypically, functionally, and metabolically undergo a timely transition from inflammatory to M2-like macrophages in vivo. With respect to the growing appreciation for in vivo examination of viral-host interactions and for the role of myeloid cells, this study elucidates the use of quantitative proteomics to reveal the role and response of distinct immune cell populations throughout the course of virus infection.

Unlabelled: In atherosclerotic plaques, the risk of rupture is increased at sites of macrophage accumulation. Activated macrophages express folate receptor-β (FR-β), which can be targeted by folate coupled to radioactive ligands to visualize vulnerability. The aim of this study was to explore the presence of activated macrophages in human atherosclerotic plaques by (99m)Tc-folate imaging and to evaluate whether this technique can discriminate between an M1-like and M2-like macrophage phenotype., Methods: Carotid endarterectomy specimens of 20 patients were incubated with (99m)Tc-folate, imaged using micro-SPECT, and divided into 3-mm slices. The mean accumulation was calculated per slice, and the distribution of M1-like and M2-like macrophages per slice was quantified by immunohistochemical staining for CD86 as well as inducible nitric oxide synthase (iNOS) for M1 and CD163 and FR-β for M2 macrophages. Monocytes from healthy donors were differentiated toward M1-like or M2-like phenotype by in vitro culturing. Messenger RNA levels of specific M1 and M2 markers were measured by reverse-transcription polymerase chain reaction and expression of FR-β, CD86, and CD163 by flow cytometry., Results: There was a heterogeneous accumulation of (99m)Tc-folate in plaques (median, 2.45 [0.77-6.40] MBq/g). Slices with the highest (99m)Tc-folate accumulation of each plaque showed significantly more expression of FR-β and CD163, compared with slices with the lowest (99m)Tc-folate accumulation, which showed significantly more expression of iNOS. In in vitro polarized macrophages, messenger RNA expression of FR-β, mannose receptor, IL-10, and matrix metalloproteinase-9 was significantly increased in M2-like macrophages, compared with M1-like macrophages. On a receptor level, CD86 was shown to be overexpressed on M1-like macrophages whereas FR-β and CD163 were overexpressed on M2-like macrophages measured by flow cytometry., Conclusion: Higher numbers of M2-like macrophages were present in areas of high (99m)Tc-folate accumulation than areas with low accumulation. It is anticipated that (99m)Tc-folate imaging using SPECT as a marker for M2-like macrophages in atherosclerosis might be a good indicator for plaque vulnerability., (© 2014 by the Society of Nuclear Medicine and Molecular Imaging, Inc.)