scholarly journals Adipocyte-Derived Exosomes Carrying Sonic Hedgehog Mediate M1 Macrophage Polarization-Induced Insulin Resistance via Ptch and PI3K Pathways

2018 ◽  
Vol 48 (4) ◽  
pp. 1416-1432 ◽  
Author(s):  
Ming Song ◽  
Lu Han ◽  
Fang-fang Chen ◽  
Di Wang ◽  
Feng Wang ◽  
...  
Keyword(s):  
Insulin Resistance ◽  
Western Blot ◽  
Sonic Hedgehog ◽  
High Glucose ◽  
Insulin Signalling ◽  
Macrophage Polarization ◽  
Raw 264.7 ◽  
Raw 264.7 Macrophages ◽  
M1 Polarization ◽  
M1 Macrophage

Background/Aims: Adipocyte-derived exosomes (ADEs) stimulate the activation of macrophages and contribute to the development of insulin resistance. Sonic Hedgehog (Shh) is an exosome-carrying protein and stimulates macrophages to secrete inflammatory cytokines. However, the impact of ADEs carrying Shh on the pro-inflammatory activation of macrophages and consequently, adipocyte insulin resistance is unclear. Methods: 3T3-L1 adipocytes were cultured with high glucose and insulin to imitate the pathogeny of insulin resistance. ADEs were isolated from conditioned media of 3T3-L1 adipocytes via differential ultracentrifugation. We explored the role of ADEs carrying Shh in the polarization of macrophages by flow cytometry. Western blot and electrophoretic mobility shift assay (EMSA) were performed to determine the activation of Shh-mediated signalling pathways. The effects of ADE-treated macrophages on adipocyte insulin signalling were studied by Western blot. Results: We found that circulating Shh-positive exosomes were increased in type 2 diabetes patients. High glucose and insulin increased the secretion of Shh-positive ADEs. The ADEs carrying Shh induced pro-inflammatory or M1 polarization of bone marrow-derived macrophages (BMDM) and RAW 264.7 macrophages. Inhibitors of Ptch and PI3K blocked the M1 polarization induced by ADEs, which suggests that ADEs carrying Shh mediated M1 macrophage polarization through the Ptch/PI3K signalling pathway. ADE-treated RAW 264.7 macrophages were subsequently used to assess the effect on insulin signalling in adipocytes. Using a co-culture assay, we showed that both ADE-treated macrophages and exosomes from these macrophages could decrease the expression of insulin-resistant substrate-1 (IRS-1) and hormone-sensitive lipase (HSL) in adipocytes. Inhibitors of Ptch and PI3K blocked the down-regulation of IRS-1 and HSL induced by ADE-treated macrophages. Conclusion: Together, these data indicate that ADEs carrying Shh induce the M1 polarization of macrophages, which contributes to insulin resistance in adipocytes through the Ptch/PI3K pathway.

scholarly journals Acid Dentin Lysate Modulates Macrophage Polarization and Osteoclastogenesis In Vitro

Materials ◽  
2021 ◽  
Vol 14 (22) ◽  
pp. 6920
Author(s):  
Jila Nasirzade ◽  
Zahra Kargarpour ◽  
Layla Panahipour ◽  
Reinhard Gruber
Keyword(s):  
Bone Marrow ◽  
Macrophage Polarization ◽  
Hematopoietic Cells ◽  
Tartrate Resistant Acid Phosphatase ◽  
Raw 264.7 ◽  
Raw 264.7 Macrophages ◽  
Polycytidylic Acid ◽  
M1 Macrophage ◽  
Bone Marrow Cultures ◽  
Marrow Cultures

Dentin prepared from extracted teeth is used as autograft for alveolar bone augmentation. Graft consolidation involves the acid lysis of dentin thereby generating a characteristic paracrine environment. Acid lysate of dentin is mimicking this environment. Acid dentin lysate (ADL) potentially targets hematopoietic cells thereby affecting their differentiation towards macrophages and osteoclasts; however, the question remains if ADL controls macrophage polarization and osteoclastogenesis. Here, we show that ADL reduced lipopolysaccharide (LPS)-induced macrophage polarization of the pro-inflammatory (M1) phenotype, indicated by attenuated Interleukin 1 (IL1), Interleukine 6 (IL6)and cyclooxygenase 2 (COX2) expression. This decrease in M1 macrophages was confirmed by the reduced phosphorylation and nuclear translocation of p65 in the LPS-exposed RAW 264.7 macrophages. Similarly, when RAW 264.7 macrophages were incubated with other agonists of Toll-like receptor (TLR) signaling e.g., FSL1, Polyinosinic-polycytidylic acid High Molecular Weight (Poly (1:C) HMW), Pam3CSK4, and imiquimod, ADL reduced the IL6 expression. We further show herein that ADL decreased osteoclastogenesis indicated by the reduced formation of multinucleated cell expressing cathepsin K and tartrate-resistant acid phosphatase in murine bone marrow cultures. Overall, our results suggest that acid dentin lysate can affect the differentiation of hematopoietic cells to M1 macrophage polarization and a decrease in osteoclastogenesis in bone marrow cultures.

Kaempferol Alleviates Corneal Transplantation Rejection by Inhibiting NLRP3 Inflammasome Activation and Macrophage M1 Polarization via Promoting Autophagy

2021 ◽  
Author(s):  
Huiwen Tian ◽  
Shumei Lin ◽  
Jing Wu ◽  
Ming Ma ◽  
Jian Yu ◽  
...  
Keyword(s):  
Nlrp3 Inflammasome ◽  
Macrophage Polarization ◽  
Corneal Transplantation ◽  
Inflammasome Activation ◽  
M1 Polarization ◽  
Nlrp3 Inflammasome Activation ◽  
M1 Macrophage ◽  
Transplantation Rejection

Abstract Corneal transplantation rejection remains a major threat to the success rate in high-risk patients. Given the many side effects presented by traditional immunosuppressants, there is an urgency to clarify the mechanism of corneal transplantation rejection and to identify new therapeutic targets. Kaempferol is a natural flavonoid that has been proven in various studies to possess anti-inflammatory, antioxidant, anticancer, and neuroprotective properties. However, the relationship between kaempferol and corneal transplantation remains largely unexplored. To address this, both in vivo and in vitro, we established a model of corneal allograft transplantation in Wistar rats and an LPS-induced inflammatory model in THP-1 derived human macrophages. In the transplantation experiments, we observed an enhancement in the NLRP3 / IL-1 β axis and in M1 macrophage polarization post-operation. In groups to which kaempferol intraperitoneal injections were administered, this response was effectively reduced. However, the effect of kaempferol was reversed after the application of autophagy inhibitors. Similarly, in the inflammatory model, we found that different concentrations of kaempferol can reduce the LPS-induced M1 polarization and NLRP3 inflammasome activation. Moreover, we confirmed that kaempferol induced autophagy and that autophagy inhibitors reversed the effect in macrophages. In conclusion, we found that kaempferol can inhibit the activation of the NLRP3 inflammasomes by inducing autophagy, thus inhibiting macrophage polarization, and ultimately alleviating corneal transplantation rejection. Thus, our study suggests that kaempferol could be used as a potential therapeutic agent in the treatment of allograft rejection.

Targeted inhibition of CD74 attenuates adipose COX-2-MIF-mediated M1 macrophage polarization and retards obesity-related adipose tissue inflammation and insulin resistance

2018 ◽  
Vol 132 (14) ◽  
pp. 1581-1596 ◽  
Author(s):  
Pei-Chi Chan ◽  
Ting-Ni Wu ◽  
Ying-Chuan Chen ◽  
Chieh-Hua Lu ◽  
Martin Wabitsch ◽  
...  
Keyword(s):  
Insulin Resistance ◽  
Adipose Tissue ◽  
Inflammatory Responses ◽  
Macrophage Polarization ◽  
Mrna Levels ◽  
Model Assessment ◽  
M1 Macrophage ◽  
Cox 2 ◽  
Highly Correlated ◽  
Targeted Inhibition

Adipose tissue (AT) inflammation is crucial to the development of obesity-associated insulin resistance. Our aim was to investigate the contribution of cyclooxygenase-2 (COX-2)/macrophage migration inhibitory factor (MIF)-mediated cross-talk between hypertrophic adipocytes and macrophages to the etiology of AT inflammation and the involvement of CD74 using human SGBS adipocytes, THP-1 macrophages and mice fed a high-fat (HF) diet. The MIF and CD74 mRNA levels in the adipocytes and stromal vascular cells (SVCs) of white fat were highly correlated with body weight (BW), homeostatic model assessment for insulin resistance (HOMA-IR), and adipose macrophage marker expression levels, especially those in SVCs. COX-2 inhibition suppressed the elevation of MIF production in HF white adipocytes as well as palmitate and hypoxic-treated SGBS adipocytes. Treatment of adipocytes transfected with shCOX-2 and siMIF or subjected to MIF depletion in the medium reversed the pro-inflammatory responses in co-incubated THP-1 cells. Inhibition of NF-κB activation reversed the COX2-dependent MIF secretion from treated adipocytes. The targeted inhibition of macrophage CD74 prevented M1 macrophage polarization in the above co-culture model. The COX-2-dependent increases in CD74 gene expression and MIF release in M1-polarized macrophages facilitated the expression of COX-2 and MIF in co-cultured SGBS adipocytes. CD74 shRNA intravenous injection suppressed HF-induced AT M1 macrophage polarization and inflammation as well as insulin resistance in mice. The present study suggested that COX-2-mediated MIF secretion through NF-κB activation from hypertrophic and hypoxic adipocytes as well as M1 macrophages might substantially contribute to the phenotypic switch of AT macrophages through CD74 in obesity. Inhibition of CD74 could attenuate AT inflammation and insulin resistance in the development of HF diet-induced obesity.

scholarly journals GRP94 regulates M1 macrophage polarization and insulin resistance

2020 ◽  
Vol 318 (6) ◽  
pp. E1004-E1013 ◽  
Author(s):  
Lili Song ◽  
Do-sung Kim ◽  
Wenyu Gou ◽  
Jingjing Wang ◽  
Ping Wang ◽  
...  
Keyword(s):  
Insulin Resistance ◽  
Insulin Sensitivity ◽  
Glucose Tolerance ◽  
Macrophage Polarization ◽  
Conditional Knockout ◽  
Marker Genes ◽  
M2 Macrophage ◽  
Macrophage Marker ◽  
M1 Macrophage ◽  
Lower Expression

Macrophage polarization contributes to obesity-induced insulin resistance. Glucose-regulated protein 94 (GRP94) is an endoplasmic reticulum (ER) chaperone specialized for folding and quality control of secreted and membrane proteins. To determine the role of GRP94 in macrophage polarization and insulin resistance, macrophage-specific GRP94 conditional knockout (KO) mice were challenged with a high-fat diet (HFD). Glucose tolerance, insulin sensitivity, and macrophage composition were compared with control mice. KO mice showed better glucose tolerance and increased insulin sensitivity. Adipose tissues from HFD-KO mice contained lower numbers of M1 macrophages, with lower expression of M1 macrophage markers, than wild-type (WT) mice. In vitro, WT adipocytes cocultured with KO macrophages retained insulin sensitivity, whereas those cultured with WT macrophages did not. In addition, compared with WT bone marrow-derived macrophages (BMDMs), BMDMs from GRP94 KO mice exhibited lower expression of M1 macrophage marker genes following stimulation with LPS or IFN-γ, and exhibited partially increased expression of M2 macrophage marker genes following stimulation with interleukin-4. These findings identify GRP94 as a novel regulator of M1 macrophage polarization and insulin resistance and inflammation.

scholarly journals Phenylmethimazole blocks palmitate-mediated induction of inflammatory cytokine pathways in 3T3L1 adipocytes and RAW 264.7 macrophages

2010 ◽  
Vol 207 (3) ◽  
pp. 343-353 ◽  
Author(s):  
Kelly D McCall ◽  
Dawn Holliday ◽  
Eric Dickerson ◽  
Brian Wallace ◽  
Anthony L Schwartz ◽  
...  
Keyword(s):  
Insulin Resistance ◽  
Vascular System ◽  
Biologically Active ◽  
Portal System ◽  
Target Cells ◽  
Raw 264.7 ◽  
Raw 264.7 Macrophages ◽  
Induce Insulin Resistance ◽  
Fat Liver ◽  
First Time

Visceral adipocytes and associated macrophages produce and release excessive amounts of biologically active inflammatory cytokines via the portal and systemic vascular system, which induce insulin resistance in insulin target tissues such as fat, liver, and muscle. Free fatty acids (FFAs) absorbed via the portal system or released from adipocytes also induce insulin resistance. In this report, we show that phenylmethimazole (C10) blocks basal IL6 and leptin production as well as basal Socs-3 expression in fully differentiated 3T3L1 cells (3T3L1 adipocytes) without affecting insulin-stimulated AKT signaling. In addition, C10 inhibits palmitate-induced IL6 and iNos up-regulation in both 3T3L1 adipocytes and RAW 264.7 macrophages, LPS-induced NF-κB and IFN-β activation in 3T3L1 cells, and LPS-induced iNos, Ifn-β, Il1β, Cxcl10, and Il6 expression in RAW 264.7 macrophages. C10 also blocks palmitate-induced Socs-3 up-regulation and insulin receptor substrate-1 (IRS-1) serine 307 phosphorylation in 3T3L1 adipocytes. Additionally, we show for the first time that although palmitate increases IRS-1 serine 307 phosphorylation in 3T3L1 adipocytes, AKT serine 473 phosphorylation is enhanced, not reduced, by palmitate. These results suggest that through inhibition of FFA-mediated signaling in adipocytes and associated macrophages, as well as possibly other insulin target cells/tissues (i.e. non-immune cells), C10 might be efficacious to prevent or reverse cytokine-induced insulin resistance seen in obesity-related insulin resistance and type 2 diabetes mellitus.

scholarly journals Taurine Antagonizes Macrophages M1 Polarization by Mitophagy-Glycolysis Switch Blockage via Dragging SAM-PP2Ac Transmethylation

2021 ◽  
Vol 12 ◽  
Author(s):  
Ling Meng ◽  
Cailing Lu ◽  
Bin Wu ◽  
Chunhua Lan ◽  
Laiming Mo ◽  
...  
Keyword(s):  
Energy Metabolism ◽  
Inflammatory Diseases ◽  
Macrophage Polarization ◽  
Metabolic Adaptation ◽  
Transcriptional Level ◽  
Low Grade ◽  
Taurine Supplementation ◽  
Polarization Model ◽  
M1 Polarization ◽  
M1 Macrophage

The excessive M1 polarization of macrophages drives the occurrence and development of inflammatory diseases. The reprogramming of macrophages from M1 to M2 can be achieved by targeting metabolic events. Taurine promotes for the balance of energy metabolism and the repair of inflammatory injury, preventing chronic diseases and complications. However, little is known about the mechanisms underlying the action of taurine modulating the macrophage polarization phenotype. In this study, we constructed a low-dose LPS/IFN-γ-induced M1 polarization model to simulate a low-grade pro-inflammatory process. Our results indicate that the taurine transporter TauT/SlC6A6 is upregulated at the transcriptional level during M1 macrophage polarization. The nutrient uptake signal on the membrane supports the high abundance of taurine in macrophages after taurine supplementation, which weakens the status of methionine metabolism, resulting in insufficient S-adenosylmethionine (SAM). The low availability of SAM is directly sensed by LCMT-1 and PME-1, hindering PP2Ac methylation. PP2Ac methylation was found to be necessary for M1 polarization, including the positive regulation of VDAC1 and PINK1. Furthermore, its activation was found to promote the elimination of mitochondria by macrophages via the mitophagy pathway for metabolic adaptation. Mechanistically, taurine inhibits SAM-dependent PP2Ac methylation to block PINK1-mediated mitophagy flux, thereby maintaining a high mitochondrial density, which ultimately hinders the conversion of energy metabolism to glycolysis required for M1. Our findings reveal a novel mechanism of taurine-coupled M1 macrophage energy metabolism, providing novel insights into the occurrence and prevention of low-grade inflammation, and propose that the sensing of taurine and SAM availability may allow communication to inflammatory response in macrophages.

scholarly journals AR Deficiency Inhibits LPS-induced M1 Response in Macrophages by Activating Autophagy

2020 ◽  
Author(s):  
Peng Cheng ◽  
Jianwei Xie ◽  
Zhiyong Liu ◽  
Jian Wang
Keyword(s):  
Nitric Oxide ◽  
Nitric Oxide Synthase ◽  
Inflammatory Responses ◽  
Macrophage Polarization ◽  
Critical Role ◽  
Transcriptional Level ◽  
Mrna Levels ◽  
M1 Polarization ◽  
M1 Macrophage ◽  
Oxide Synthase

Abstract Macrophage M1 polarization mediates inflammatory responses and tissue damage. Recently, aldose reductase (AR) has been shown to play a critical role in of M1 polarization in macrophages. However, the underlying mechanisms are unknown. Here, we demonstrated, for the first time, that AR deficiency repressed the induction of inducible nitric oxide synthase in lipopolysaccharide (LPS)-stimulated macrophages via activation of autophagy. This suppression was related to a defect in the inhibitor of nuclear factor κB (NF-κB) kinase (IKK) complex in the classical NF-κB pathway. However, the mRNA levels of the IKKβ and IKKγ were not reduced in LPS-treated AR knockout (KO) macrophages, indicating that their proteins were downregulated at the post-transcriptional level. We discovered that LPS stimuli induced the recruitment of more beclin1 and increased autophagosome formation in AR-deficient macrophages. Blocking autophagy by 3-methyladenine and ammonium chloride treatment restored IKKβ and IKKγ protein levels and increased nitric oxide synthase production in LPS-stimulated AR-deficient macrophages. More assembled IKKβ and IKKγ undergo ubiquitination and recruit the autophagic adaptor p62 in LPS-induced AR KO macrophages, promoting their delivery to autophagosomes and lysosomes. Collectively, these findings suggest that AR deficiency involves in the regulation of NF-κB signaling, and extends the role of selective autophagy in fine-tuned M1 macrophage polarization.

scholarly journals MiR-19a-3p Suppresses M1 Macrophage Polarization by Inhibiting STAT1/IRF1 Pathway

2021 ◽  
Vol 12 ◽  
Author(s):  
Xiaoxiao Zhu ◽  
Qiang Guo ◽  
Jing Zou ◽  
Bin Wang ◽  
Zhen Zhang ◽  
...  
Keyword(s):  
Macrophage Polarization ◽  
Luciferase Reporter ◽  
Mouse Lung ◽  
Interferon Regulatory Factor 1 ◽  
Macrophages Polarization ◽  
M1 Polarization ◽  
M1 Macrophage ◽  
Activated Macrophage ◽  
Alternatively Activated

Macrophages, an important type of immune cells, are generally polarized to classically activated macrophage (M1) or alternatively activated macrophage (M2) to respond to environmental stimuli. Signal transducer and activator of transcription 1 (STAT1), a very important transcription factor, can promote M1 macrophage polarization. However, the mechanisms of regulating STAT1 in macrophage polarization remain unclear. In the present study, STAT1 was markedly elevated, however, miR-19a-3p was down-regulated in interferon (IFN)-γ and lipopolysaccharide (LPS) treated RAW264.7 cells, and dual-luciferase reporter assay identified that miR-19a-3p directly targeted STAT1 by binding to its 3′UTR. Up-regulated miR-19a-3p inhibited M1 polarization by targeting STAT1/interferon regulatory factor 1 (IRF1) and vice versa in vitro. Consistently, overexpression of miR-19a-3p in LPS treated mice by systemically administering agomiR-19a-3p effectively reduced the inflammation in mouse lung tissues, and inhibited M1 macrophage polarization via suppressing STAT1/IRF1 pathway. In summary, our study confirmed that miR-19a-3p, as a direct regulator of STAT1, inhibited M1 macrophages polarization. The miR-19a-3p/STAT1/IRF1 pathway can potentially be used to design novel immunotherapy for modulating macrophage polarization.

Homocysteine elicits an M1 phenotype in murine macrophages through an EMMPRIN-mediated pathway

2015 ◽  
Vol 93 (7) ◽  
pp. 577-584 ◽  
Author(s):  
Lee J. Winchester ◽  
Sudhakar Veeranki ◽  
Srikanth Givvimani ◽  
Suresh C. Tyagi
Keyword(s):  
Nitric Oxide ◽  
Matrix Metalloproteinase ◽  
Cell Lines ◽  
Inflammatory Diseases ◽  
Raw 264.7 ◽  
Macrophage Phenotype ◽  
Raw 264.7 Macrophages ◽  
M1 Macrophage ◽  
Endothelial Nitric Oxide ◽  
The Impact

Introduction: Hyperhomocysteinemia (HHcy) is associated with inflammatory diseases and is known to increase the production of reactive oxygen species (ROS), matrix metalloproteinase (MMP)-9, and inducible nitric oxide synthase, and to decrease endothelial nitric oxide production. However, the impact of HHcy on macrophage phenotype differentiation is not well-established. It has been documented that macrophages have 2 distinct phenotypes: the “classically activated/destructive” (M1), and the “alternatively activated/constructive” (M2) subtypes. We hypothesize that HHcy increases M1 macrophage differentiation through extracellular matrix metalloproteinase inducer (EMMPRIN), a known inducer of matrix metalloproteinases. Methods: murine J774A.1 and Raw 264.7 macrophages were treated with 100 and 500 μmol/L Hcy, respectively, for 24 h. Samples were analyzed using Western blotting and immunocytochemistry. Results: Homocysteine treatment increased cluster of differentiation 40 (CD40; M1 marker) in J774A.1 and Raw 264.7 macrophages. MMP-9 was induced in both cell lines. EMMPRIN protein expression was also increased in both cell lines. Blocking EMMPRIN function by pre-treating cells with anti-EMMPRIN antibody, with or without Hcy, resulted in significantly lower expression of CD40 in both cell lines by comparison with the controls. A DCFDA assay demonstrated increased ROS production in both cell lines with Hcy treatment when compared with the controls. Conclusion: Our results suggest that HHcy results in an increase of the M1 macrophage phenotype. This effect seems to be at least partially mediated by EMMPRIN induction.

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