TNF-Like Ligand 1 Aberrance Aggravates Nonalcoholic Steatohepatitis via M1 Macrophage Polarization

Nonalcoholic steatohepatitis (NASH) is a progressive, chronic liver disease worldwide which imposes a large economic burden on society. M1/M2 macrophage balance destruction and recruitment of mononuclear immune cells to the liver play critical roles in NASH. Several studies have shown that the expression of TNF-like ligand 1 aberrance (TL1A) increased in macrophages associated with many inflammatory diseases, for example, inflammatory bowel disease, primary biliary cholangitis, and liver fibrosis. One recent research showed that weight, abdominal adipose, and liver leptin, one of the critical fat cytokines, were reduced in TL1A knockout mice. However, the functional and molecular regulatory mechanisms of TL1A on macrophage polarization and recruitment in NASH have yet to be clarified. The authors found that high fructose high fat diet and methionine-choline deficiency diet induced the expression of TL1A in macrophages of liver tissue from murine NASH models. Myeloid-specific TL1A overexpressed mice showed exacerbated steatohepatitis with increased hepatic lipid accumulation, inflammation, liver injury, and apoptosis. M1 macrophages’ infiltration and the production of proinflammatory and chemotactic cytokines increased in liver of NASH mouse models with myeloid-specific TL1A overexpressed. Furthermore, this paper revealed that bone marrow-derived macrophages and Kupffer cells with overexpression of TL1A exacerbated the lipid accumulation and expression of proinflammatory factors in the murine primary hepatocytes after free fatty acid treatment in vitro. In conclusion, TL1A-mediated M1-type macrophage polarization and recruitment into the liver promoted steatohepatitis in murine NASH.

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847 Inflammasome activation in M2 macrophage restrain the immune suppressive function

Journal for ImmunoTherapy of Cancer ◽

10.1136/jitc-2020-sitc2020.0847 ◽

2020 ◽

Vol 8 (Suppl 3) ◽

pp. A900-A900

Author(s):

Ronghua Zhang ◽

Tienan Wang ◽

Qing Lin

Keyword(s):

T Cell ◽

T Cell Activation ◽

Culture System ◽

Cell Activation ◽

Macrophage Polarization ◽

Inflammasome Activation ◽

M2 Macrophage ◽

M1 Macrophage ◽

Suppressive Phenotype

BackgroundMacrophage is an important component in tumor microenvironment (TME) and plays multiple roles in tumor initiation, progression and metastases. In response to various stimuli within TME, macrophage exhibits high level of functional heterogeneity. There are two distinct groups of macrophages: M1 macrophage exhibits pro-inflammatory phenotype with high levels of TNF-a, IL-6, and IL-1ß, while M2 macrophage displays immune suppressive phenotype with high levels of anti-inflammatory cytokines such as IL-10 and TGF-ß. In response to the M2 cytokines, myeloid cells within the TME further acquire higher expression of PD-L1 and thus inactivate T cells. M2 cytokines can also directly inhibit T cell activation. As a result, re-polarizing M2 macrophages becomes a key concept for cancer immunotherapy. The NLRP3 inflammasome is acquired by macrophages to fight against endogenous danger signals. Macrophage NLRP3 activation has been observed in several tumor models, but the function of NLRP3 on macrophage polarity remains controversial. Inflammasome activation with IL-1ß/IL-18 secretion was reported to promote M1 polarization. However, NLRP3 activation was also reported to promote M2 polarity through up-regulation of IL4 in asthma modelMethodsHere, we have established an in vitro human macrophage NLRP3 activation system (figure 1), coupled with M2 macrophage polarization assay, to dissect the role of NLRP3 in macrophage phenotype.ResultsOur results indicate that NLRP3 activation restrained M2 phenotype and further enhanced T cell activation in an M2/T cell co-culture system (figure 2).Abstract 847 Figure 1Inflammasome activation polarize M2 macrophage intUse LPS/ATP to stimulate NLRP3 in M2 macrophage and demonstrate NLRP3 activation could reduce CD163 and increase CD86Abstract 847 Figure 2Inflammasome in M2 rescue T cell activationestablish M2/T co-culture system in vitro to demonstrate M2 could suppress T activation while Inflammatory M2 could partial rescue the suppressive phenotypeConclusionsInflammasome could be the potential target for cancer by modulating T cell activation through macrophage polarization regulation

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Contribution of Thrombospondin-1 and -2 to Lipopolysaccharide-Induced Acute Respiratory Distress Syndrome

Mediators of Inflammation ◽

10.1155/2021/8876484 ◽

2021 ◽

Vol 2021 ◽

pp. 1-22

Author(s):

Qiang Li ◽

Xiaoxiao Fu ◽

Jiang Yuan ◽

Shu Han

Keyword(s):

T Regulatory Cells ◽

Inflammatory Diseases ◽

Macrophage Polarization ◽

Endothelial Permeability ◽

M2 Macrophage ◽

Vascular Endothelial ◽

Macrophage Phenotype ◽

Thrombospondin 1

Thrombospondin (TSP) proteins have been shown to impact T-cell adhesion, migration, differentiation, and apoptosis. Thrombospondin-1 (TSP-1) is specifically upregulated in several inflammatory diseases and can effectively promote lipopolysaccharide- (LPS-) induced inflammation. In contrast, thrombospondin-2 (TSP-2) has been associated with activation of “anti-inflammatory” T-regulatory cells (Tregs). In this study, we investigated the effects of both TSP-1 and TSP-2 overexpression on macrophage polarization and activation in vitro and in vivo. We analyzed the effects of TSP-1 and TSP-2 on inflammation, vascular endothelial permeability, edema, ultrastructural morphology, and apoptosis in lung tissues of an ARDS mouse model and cultured macrophages. Our results demonstrated that TSP-2 overexpression effectively attenuated LPS-induced ARDS in vivo and promoted M2 macrophage phenotype polarization in vitro. Furthermore, TSP-2 played a role in regulating pulmonary vascular barrier leakage by activating the PI3K/Akt pathway. Overall, our findings indicate that TSP-2 can modulate inflammation and could therefore be a potential therapeutic target against LPS-induced ARDS.

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A Benzenediamine Analog FC-99 Drives M2 Macrophage Polarization and Alleviates Lipopolysaccharide- (LPS-) Induced Liver Injury

Mediators of Inflammation ◽

10.1155/2019/7823069 ◽

2019 ◽

Vol 2019 ◽

pp. 1-9 ◽

Cited By ~ 2

Author(s):

Wei Gong ◽

Haiyan Zhu ◽

Li Lu ◽

Yayi Hou ◽

Huan Dou

Keyword(s):

Liver Injury ◽

Macrophage Polarization ◽

M2 Macrophage ◽

M1 Macrophage ◽

M2 Macrophage Polarization ◽

Underlying Mechanisms ◽

Sirna Knockdown ◽

Lower Expression ◽

Alternatively Activated

Macrophages have variable functional phenotypes, high diversity, and plasticity and are involved in the pathogenesis of sepsis-induced liver injury. Alteration of macrophage polarization through activated (M1) macrophage to alternatively activated (M2) macrophage has emerged as a potential therapeutic strategy. This study was designed to explore the effect of a benzenediamine analog FC-99 on macrophage polarization in vitro and lipopolysaccharide- (LPS-) induced liver injury followed by the underlying mechanisms. For in vitro experiments, FC-99 inhibited M1-related macrophage factors and promoted M2-related markers induced by IL-4 in the mouse macrophage cell line RAW264.7. Moreover, FC-99-induced macrophages polarized to M2 phenotype which could be repressed by a PPAR-γ inhibitor but not STAT6 siRNA knockdown, indicating FC-99-induced M2 macrophage polarization through PPAR-γ rather than STAT6 signal. In LPS-induced septic mice, FC-99 pretreated mice displayed lower expression of M1 markers together with the increased M2 marker CD206 and improvement of liver injury. These findings illustrated that FC-99 could promote M2 macrophage polarization via PPAR-γ signaling and seemed to be a potential therapeutic candidate for inflammatory liver injury.

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Anti-Inflammatory Effect of Curcumin on the Mouse Model of Myocardial Infarction through Regulating Macrophage Polarization

Mediators of Inflammation ◽

10.1155/2021/9976912 ◽

2021 ◽

Vol 2021 ◽

pp. 1-19

Author(s):

Shaoxi Yan ◽

Mo Zhou ◽

Xiaoyun Zheng ◽

Yuanyuan Xing ◽

Juan Dong ◽

...

Keyword(s):

Myocardial Infarction ◽

Ventricular Remodeling ◽

Macrophage Polarization ◽

M2 Macrophage ◽

M1 Macrophages ◽

Macrophage Marker ◽

M1 Macrophage ◽

Anti Inflammatory

Inflammation causes tissue damage and promotes ventricular remodeling after myocardial infarction (MI), and the infiltration and polarization of macrophages play an important role in regulating inflammation post-MI. Here, we investigated the anti-inflammatory function of curcumin after MI and studied its relationship with macrophage polarization. In vivo, curcumin not only attenuated ventricular remodeling 3 months after MI but also suppressed inflammation during the first 7 days post-MI. Importantly, the results of qPCR and immunochemistry showed that curcumin decreased M1 (iNOS, CCL2, and CD86) but increased M2 macrophage (Arg1, CD163, and CD206) marker expression in the myocardium of MI mice during the first 7 days post-MI. And flow cytometry analysis indicated that curcumin suppressed M1 (CD45+Gr-1-CD11b+iNOS+ cells) but enhanced M2 macrophage (CD45+Gr-1-CD11b+Arg+ cells) expansion in the myocardium of MI mice during the first 7 days post-MI. In vitro, curcumin decreased LPS/IFNγ-elevated M1 macrophage marker (iNOS and CD86) expression and the proportion of M1 macrophages (iNOS+F4/80+ cells) but increased LPS/IFNγ-suppressed M2 macrophage marker (Arg1 and CD206) expression and the proportion of M2 macrophages (Arg1+F4/80+ cells). In addition, curcumin modulates M1/M2 macrophage polarization partly via AMPK. In conclusion, curcumin suppressed the MI-induced inflammation by modulating macrophage polarization partly via the AMPK pathway.

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The N6-methyladenosine (m6A)-forming enzyme METTL3 facilitates M1 macrophage polarization through the methylation of STAT1 mRNA

AJP Cell Physiology ◽

10.1152/ajpcell.00212.2019 ◽

2019 ◽

Vol 317 (4) ◽

pp. C762-C775 ◽

Cited By ~ 9

Author(s):

Yihan Liu ◽

Zhujiang Liu ◽

Hao Tang ◽

Yicong Shen ◽

Ze Gong ◽

...

Keyword(s):

Epigenetic Modification ◽

Macrophage Polarization ◽

M2 Macrophage ◽

M1 Polarization ◽

M1 Macrophage ◽

Mouse Macrophages ◽

Rna Immunoprecipitation ◽

M2 Macrophage Polarization ◽

Plasmid Transfection

Compelling evidence indicates that epigenetic regulations orchestrate dynamic macrophage polarization. N6-methyladenosine (m6A) methylation is the most abundant epigenetic modification of mammalian mRNA, but its role in macrophage polarization is still completely unknown. Here, we show that the m6A-catalytic enzyme methyltransferase like 3 (METTL3) is specifically upregulated following the M1 polarization of mouse macrophages. Furthermore, METTL3 knockdown through siRNA transfection markedly inhibited M1, but enhanced M2, macrophage polarization. Conversely, its overexpression via plasmid transfection greatly facilitated M1, but attenuated M2, macrophage polarization. Further methylated RNA immunoprecipitation and in vitro m6A methylation assays suggested that METTL3 directly methylates mRNA encoding signal transducer and activator of transcription 1 (STAT1), a master transcription factor controlling M1 macrophage polarization, at its coding sequence and 3′-untranslated regions. In addition, METTL3-mediated STAT1 mRNA methylation significantly increased mRNA stability and subsequently upregulated STAT1 expression. In conclusion, METTL3 drives M1 macrophage polarization by directly methylating STAT1 mRNA, potentially serving as an anti-inflammatory target.

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Saponin from Periploca forrestii Schltr Mitigates Oxazolone-Induced Atopic Dermatitis via Modulating Macrophage Activation

Mediators of Inflammation ◽

10.1155/2020/4346367 ◽

2020 ◽

Vol 2020 ◽

pp. 1-13

Author(s):

Luting Zeng ◽

Yingqin Liu ◽

Congcong Xing ◽

Yijie Huang ◽

Xin Sun ◽

...

Keyword(s):

Atopic Dermatitis ◽

Macrophage Activation ◽

Skin Diseases ◽

Nuclear Translocation ◽

Macrophage Polarization ◽

M2 Macrophage ◽

Mouse Bone Marrow ◽

Inflammatory Skin Diseases ◽

M1 Macrophage

Atopic dermatitis (AD) is a relapsing, acute, and chronic skin disease featured by intractable itching, eczematous skin. Conventional therapies based on immunosuppression such as corticosteroids are associated with multiple adverse reactions. Periploca forrestii Schltr saponin (PFS) was shown to potently inhibit murine arthritis by protecting bone and cartilage injury and suppressing NF-κB activation. However, its therapeutic effect on oxazolone-induced atopic dermatitis (AD) and the underlying mechanisms on macrophage are still unclear. The AD-like dermatitis was induced by repeated oxazolone challenge to the skin of BALB/c mice in vivo. Blood and ears were biochemically or histologically processed. RT-PCR, western blotting, and ELISA were conducted to evaluate the expression of macrophage factors. Mouse bone marrow-derived macrophages (BMDMs) stimulated with lipopolysaccharide (LPS) were used as a model in vitro. PFS treatment inhibited AD-like dermatitis development. PFS downregulated epidermis thickness and cell infiltration, with histological analysis of the skin lesion. PFS alleviated plasma immunoglobulin (Ig) E, IgG2a, and IgG1 levels. PFS downregulated the expression of M1 macrophage factors, tumor necrosis factor- (TNF-) α, interleukin- (IL-) 6, monocyte chemotactic protein-1 (MCP-1), and nitric oxide synthase2 (NOS2), and M2 macrophage factors, IL-4, arginase1 (Arg1) and CD163 in AD-like skin, which were confirmed by western blot and ELISA analysis. In addition, PFS inhibited LPS-induced macrophage polarization via the inhibition of the phosphorylation of signal transducer and activator of transcription 3 (STAT3) and nuclear translocation of NF-κB p65. These results suggest that PFS exerted an antidermatitis effect against oxazolone by modulating macrophage activation. PFS administration might be useful in the treatment of AD and inflammatory skin diseases.

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Ubiquitylation of MFHAS1 by the ubiquitin ligase praja2 promotes M1 macrophage polarization by activating JNK and p38 pathways

Cell Death and Disease ◽

10.1038/cddis.2017.102 ◽

2017 ◽

Vol 8 (5) ◽

pp. e2763-e2763 ◽

Cited By ~ 16

Author(s):

Jing Zhong ◽

Huihui Wang ◽

Wankun Chen ◽

Zhirong Sun ◽

Jiawei Chen ◽

...

Keyword(s):

Ubiquitin Ligase ◽

Macrophage Polarization ◽

M2 Macrophage ◽

Toll Like Receptor ◽

M1 Macrophage ◽

M2 Macrophage Polarization ◽

P38 Pathway

Abstract Sepsis is a systemic inflammation caused by infection. The balance between M1–M2 macrophage polarization has an essential role in the pathogenesis of sepsis. However, the exact mechanism underlying macrophage polarization is unclear. We previously showed that levels of malignant fibrous histiocytoma amplified sequence 1 (MFHAS1) were significantly elevated in septic patients compared with those in nonseptic patients, and involved in the activation of Toll-like receptor (TLR) 2/c-Jun N-terminal kinase (JNK)/nuclear factor (NF)-κB pathway. In the present study, we explored whether MFHAS1 was involved in macrophage polarization and determined the effect of MFHAS1 on inflammation. We performed in vitro pulldown assays and in vivo co-immunoprecipitation assays and found that E3 ubiquitin ligase praja2 could directly bind to MFHAS1. In situ immunostaining analysis confirmed the colocalization of endogenous praja2 with MFHAS1. We first reported that praja2 promotes the accumulation of ubiquitylated MFHAS1 but does not degrade it. Moreover, our results indicate that MFHAS1 ubiquitylation by praja2 positively regulates TLR2-mediated JNK/p38 pathway and promotes M1 macrophage polarization, M2 to M1 macrophage transformation and inflammation.

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Weak UVB Irradiation Promotes Macrophage M2 Polarization and Stabilizes Atherosclerosis

Journal of Cardiovascular Translational Research ◽

10.1007/s12265-021-10189-7 ◽

2021 ◽

Author(s):

Xin-Yun Li ◽

Tao Qin ◽

Peng-Fei Zhang ◽

Wen-jiang Yan ◽

Ling-Li Lei ◽

...

Keyword(s):

Nitric Oxide ◽

Macrophage Polarization ◽

Atherosclerotic Lesion ◽

Ultraviolet B ◽

M2 Macrophage ◽

Uvb Irradiation ◽

Plaque Stability ◽

M1 Macrophage

AbstractAtherosclerosis (AS) is a chronic cardiovascular disease endangering human health and is one of the most common causes of myocardial infarction and stroke. Macrophage polarization plays a vital role in regulating plaque stability. As an important component of sunlight, ultraviolet B (UVB) has been proven to promote vitamin D and nitric oxide synthesis. This research used an AS model in ApoE−/− mice to study the effects of UVB on macrophage polarization and atherosclerotic plaque stability. In vitro, UVB irradiation increased arginase-I (Arg-I, M2 macrophage) and macrophage mannose receptor (CD206) expression, while the expression of inducible nitric oxide synthase (iNOS) (M1 macrophage) and CD86 was decreased. UVB promoted Akt phosphorylation in vitro. In vivo, UVB irradiation promoted the stabilization of atherosclerotic lesion plaques, while the phenotype of M2 macrophages increased. Our research provides new evidence for UVB in preventing and treating atherosclerosis.

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NFATc3 deficiency reduces the classical activation of adipose tissue macrophages

Journal of Molecular Endocrinology ◽

10.1530/jme-18-0070 ◽

2018 ◽

Vol 61 (3) ◽

pp. 79-89 ◽

Cited By ~ 9

Author(s):

Li Hu ◽

Fengli He ◽

Meifeng Huang ◽

Meihua Peng ◽

Zhiguang Zhou ◽

...

Keyword(s):

Insulin Resistance ◽

Adipose Tissue ◽

Transcriptional Activation ◽

Macrophage Polarization ◽

Liver Fat ◽

M2 Macrophage ◽

Activated T Cells ◽

M1 Macrophage ◽

Proinflammatory Factors

Nuclear factors of activated T cells (NFAT) c3 have a prominent role in the regulation of proinflammatory factors in immune cells. The classically activated M1 macrophages are key players in the initiation and maintenance of adipose tissue (AT) inflammation. The role of NFATc3 in obesity and AT inflammation is unknown. We set out to determine how deficiency of NFATc3 effected macrophage polarization, inflammation and insulin resistance in visceral AT of high-fat diet (HFD)-fed mice. Nfatc3−/− and WT mice were fed a HFD for 8–17 weeks. Epididymal white AT (eWAT) F4/80(+) cells were characterized by fluorescence-activated cell sorting and quantitative RT-PCR. Results showed that Nfatc3−/− mice developed HFD-induced obesity similar to WT mice, but insulin sensitivity and glucose tolerance were improved, and liver fat accumulation was reduced in Nfatc3−/− mice compared to WT control mice. Moreover, M1 macrophage content and proinflammatory factors were reduced, whereas the alternatively activated M2 macrophage content was increased in eWAT of HFD-fed Nfatc3−/− mice compared to that of WT mice. In addition, eWAT insulin signaling was improved in HFD-fed Nfatc3−/− mice. Importantly, after bone-marrow-derived macrophages had been isolated from Nfatc3−/− mice and cultured in vitro, treatment of these cells with interferon-γ and lipopolysaccharide resulted in reduction of M1 inflammatory markers, suggesting that NFATc3 promoted M1 polarization by a cell-autonomous mechanism. The results demonstrated that NFATc3 played an important role in M1 macrophage polarization, AT inflammation and insulin resistance in response to obesity through transcriptional activation of proinflammatory genes.

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Neutrophils Facilitate Prolonged Inflammasome Response in the DAMP-Rich Inflammatory Milieu

Frontiers in Immunology ◽

10.3389/fimmu.2021.746032 ◽

2021 ◽

Vol 12 ◽

Author(s):

Seunghwan Son ◽

Sung-Hyun Yoon ◽

Byeong Jun Chae ◽

Inhwa Hwang ◽

Do-Wan Shim ◽

...

Keyword(s):

Molecular Mechanisms ◽

Inflammatory Diseases ◽

Macrophage Polarization ◽

Interleukin 1Β ◽

Inflammasome Activation ◽

M2 Macrophage ◽

Mitochondrial Depolarization ◽

Activated Neutrophils

Aberrant inflammasome activation contributes to various chronic inflammatory diseases; however, pyroptosis of inflammasome-active cells promptly terminates local inflammasome response. Molecular mechanisms underlying prolonged inflammasome signaling thus require further elucidation. Here, we report that neutrophil-specific resistance to pyroptosis and NLRP3 desensitization can facilitate sustained inflammasome response and interleukin-1β secretion. Unlike macrophages, inflammasome-activated neutrophils did not undergo pyroptosis, indicated by using in vitro cell-based assay and in vivo mouse model. Intriguingly, danger-associated molecular patterns (DAMP)-rich milieu in the inflammatory region significantly abrogated NLRP3-activating potential of macrophages, but not of neutrophils. This macrophage-specific NLRP3 desensitization was associated with DAMP-induced mitochondrial depolarization that was not observed in neutrophils due to a lack of SARM1 expression. Indeed, valinomycin-induced compulsory mitochondrial depolarization in neutrophils restored inflammasome-dependent cell death and ATP-induced NLRP3 desensitization in neutrophils. Alongside prolonged inflammasome-activating potential, neutrophils predominantly secreted interleukin-1β rather than other proinflammatory cytokines upon NLRP3 stimulation. Furthermore, inflammasome-activated neutrophils did not trigger efferocytosis-mediated M2 macrophage polarization essential for the initiation of inflammation resolution. Taken together, our results indicate that neutrophils can prolong inflammasome response via mitochondria-dependent resistance to NLRP3 desensitization and function as major interleukin-1β-secreting cells in DAMP-rich inflammatory region.

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