scholarly journals LSD1 Facilitates Pro-Inflammatory Polarization of Macrophages by Repressing Catalase

Cells ◽  
2021 ◽  
Vol 10 (9) ◽  
pp. 2465
Author(s):  
Maciej Sobczak ◽  
Magdalena Strachowska ◽  
Karolina Gronkowska ◽  
Iwona Karwaciak ◽  
Łukasz Pułaski ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Chromatin Remodeling ◽  
Macrophage Activation ◽  
Gene Promoter ◽  
Immunosuppressive Drugs ◽  
Acetylation Status ◽  
M1 Polarization ◽  
Inflammatory Phenotype ◽  
Catalase Deficiency ◽  
Pro Inflammatory Cytokines

The increased level of hydrogen peroxide accompanies some modes of macrophage specification and is linked to ROS-based antimicrobial activity of these phagocytes. In this study, we show that activation of toll-like receptors with bacterial components such as LPS is accompanied by the decline in transcription of hydrogen peroxide decomposing enzyme-catalase, suppression of which facilitates the polarization of human macrophages towards the pro-inflammatory phenotype. The chromatin remodeling at the CAT promoter involves LSD1 and HDAC1, but activity of the first enzyme defines abundance of the two proteins on chromatin, histone acetylation status and the CAT transcription. LSD1 inhibition prior to macrophage activation with LPS prevents CAT repression by enhancing the LSD1 and interfering with the HDAC1 recruitment to the gene promoter. The maintenance of catalase level with LSD1 inhibitors during M1 polarization considerably limits LPS-triggered expression of some pro-inflammatory cytokines and markers such as IL1β, TNFα, COX2, CD14, TLR2, and IFNAR, but the effect of LSD1 inhibitors is lost upon catalase deficiency. Summarizing, activity of LSD1 allows for the CAT repression in LPS stimulated macrophages, which negatively controls expression of some key pro-inflammatory markers. LSD1 inhibitors can be considered as possible immunosuppressive drugs capable of limiting macrophage M1 specialization.

scholarly journals Evaluation of the role of CD47 in sickle cell disease

2021 ◽  
Author(s):  
Basmah Eldakhakhny ◽  
Hadeel Al Sadoun ◽  
Nehal Bin Taleb ◽  
Dunya Ahmed Nori ◽  
Nawal Helmi ◽  
...  
Keyword(s):  
Inflammatory Cytokines ◽  
Annexin V ◽  
Cell Disease ◽  
Phagocytic Cells ◽  
Surface Marker Expression ◽  
Inflammatory Phenotype ◽  
Healthy Control ◽  
Cell Surface Marker Expression ◽  
Pro Inflammatory Cytokines

AbstractCD47 is a self-marker expressed on the surface of RBCs and work to prevent the process of phagocytosis. SIRPα is the ligand of CD47 that is expressed on the surface of phagocytic cells, such as macrophages, to control the removal of dead/diseased cells. This study aimed to examine the expression of CD47 on RBCs and SIRPα on PBMC cells in SCD patients and the apoptosis of SCD RBCs. We also measured the levels of pro-inflammatory cytokines in SCD patients and correlated it with the cell surface marker expression of CD47 and SIRPα to determine whether CD47 and/or SIRPα played a role in promoting the pro-inflammatory phenotype in SCD. Whole blood samples were drawn from SCD patients, and healthy control and PBMC were isolated and stained with SIRPα. Change in CD47, apoptosis by annexin V marker, and pro-inflammatory cytokines were measured and correlation among these variants was determined. The expression of CD47 was significantly decreased and the apoptosis was increased in RBCs of SCD patients. A higher level of pro-inflammatory cytokines, IL-6 and IL-1β, was found in SCD patients and IL-1β was found to be inversely correlated with SIRPα expression. Our data showed that CD47 of erythrocytes of SCD samples is reduced and that the apoptosis is increased in those patients. Based on the role of CD47, we suggest that increased apoptosis in SCD would be impacted by the reduced level of CD47. An inverse relationship was found between SIRPα marker on PBMC and the increased production of pro-inflammatory cytokines in SCD.

scholarly journals Inhibition of PAR1 attenuates meningeal macrophage activation and vascular inflammation in a rat model of thrombin-induced hydrocephalus

2019 ◽  
Author(s):  
Xiaodi Hao ◽  
Xianghua Ye ◽  
Dan Shen ◽  
Chensheng Le ◽  
Lusha Tong ◽  
...  
Keyword(s):  
Subarachnoid Space ◽  
Vascular Inflammation ◽  
Intercellular Adhesion Molecule ◽  
Intraventricular Injection ◽  
Thrombin Injection ◽  
Intercellular Adhesion Molecule 1 ◽  
Neuron Loss ◽  
Meningeal Inflammation ◽  
M1 Polarization ◽  
Pro Inflammatory Cytokines

Abstract Background and Purpose— Our previous studies demonstrated that intraventricular injection of thrombin could induce hydrocephalus. The inflammation of subarachnoid space plays a key role in hydrocephalus. As thrombin, inducing coagulation, could contribute to inflammation, its effects on subarachnoid space have not been well studied. Macrophagic dysfunction may contribute to this course. However, the mechanisms that how thrombin affects macrophage in subarachnoid space have not been illustrated. Our aim was to explore the possible role that macrophage played in thrombin-induced meningeal inflammation, and to furtherly understand its contribution during thrombin-induced hydrocephalus. Methods— There were two parts in this study. Firstly, rats had an intraventricular injection of saline or thrombin. Secondly, rats received thrombin injection with vehicle or PAR1 antagonist treatment. Immunofluorescence staining was applied to observe the activation of meningeal macrophage and the expression of NeuN in the cortex. Meanwhile, the expression of intercellular adhesion molecule 1 (ICAM1) in meningeal vessels were tested to detect the vascular inflammation. Western blot was applied to measure the secretion of pro-inflammatory cytokines (IL-1β and IFNγ). Results— Our results demonstrated that intraventricular injection of thrombin caused significant activation of meningeal macrophages, vascular inflammation, and neuron loss. Inhibition of PAR1 pathway attenuated the M1 polarization of meningeal macrophage, reduced the inflammatory infiltrations and prevented the neuron loss, as well as hydrocephalus after thrombin injection. Conclusions— Clinically available PAR1 antagonists may offer a novel therapeutic approach candidate for the prevention or the management of inflammation in hemorrhage-induced hydrocephalus.

Abstract 178: Cholesterol Limits Macrophage Activation in Response to Intracerebral Hemorrhage-Relevant Signals

Stroke ◽  
2020 ◽  
Vol 51 (Suppl_1) ◽  
Author(s):  
Jonathan H DeLong ◽  
Sofia Velazquez ◽  
Margaret J Landreneau ◽  
Lauren H Sansing
Keyword(s):  
Intracerebral Hemorrhage ◽  
Macrophage Activation ◽  
Cholesterol Content ◽  
Brain Parenchyma ◽  
Activation Markers ◽  
Multiple Systems ◽  
Murine Bone Marrow ◽  
Inflammatory Phenotype ◽  
Injury Models ◽  
The Brain

Introduction: In response to intracerebral hemorrhage (ICH), monocytes are recruited to the brain parenchyma, where they differentiate into macrophages and contribute to a pathological inflammatory response. However, by day 3 after ICH, brain macrophages have adopted a more reparative phenotype and are important for clearance of apoptotic cells and recovery. The signals that control this inflammatory to reparative differentiation are incompletely understood, but cholesterol has been found to limit macrophage activation in multiple systems. The brain has the highest cholesterol content of any organ and we hypothesized that cholesterol uptake by macrophages limits inflammation and promotes the development of reparative macrophages following ICH. Methods and Results: Murine bone marrow-derived macrophages were stimulated with a cocktail of thrombin, S100A8, and IL-1b in order to mimic the Danger-Associated Molecular Patterns present in the brain after ICH (ICH-DAMP), LPS, or vehicle for 14-18 hours. Cytokine production was quantified by cytometric bead array and activation markers by flow cytometry. ICH-DAMP was found to upregulate CCL2, IL-6 and TNF, recapitulating the inflammatory phenotype seen in the first days after ICH. However, when cells were stimulated in the presence of cholesterol, production of CCL2, IL-6, and TNF were limited. Dectin-1 has inhibitory properties in some sterile injury models. ICH-DAMP was found to limit expression of dectin-1, and cholesterol reversed this inhibition. Exposure to exogenous cholesterol also upregulated the cholesterol transporter ABCA1, allowing cells to efflux excess cholesterol. The drug Valspodar was therefore used to block cholesterol efflux and was found to further limit ICH-DAMP-mediated upregulation of CCL2. Conclusion: These results suggest that the cholesterol in the brain may limit macrophage activation in response to the stimuli present during intracerebral hemorrhage.

scholarly journals Cholangiocyte-Derived Exosomal lncRNA H19 Promotes Macrophage Activation and Hepatic Inflammation under Cholestatic Conditions

Cells ◽  
2020 ◽  
Vol 9 (1) ◽  
pp. 190 ◽  
Author(s):  
Xiaojiaoyang Li ◽  
Runping Liu ◽  
Yanyan Wang ◽  
Weiwei Zhu ◽  
Derrick Zhao ◽  
...  
Keyword(s):  
Kupffer Cells ◽  
Noncoding Rna ◽  
Macrophage Activation ◽  
Critical Role ◽  
Vital Role ◽  
Primary Biliary Cholangitis ◽  
M1 Polarization ◽  
Hepatic Macrophages ◽  
Duct Ligation ◽  
Almost All

Activation of hepatic macrophages represents the critical driving force to promote cholestatic liver injury. Exosomes, as important small extracellular vesicles released by almost all types of cells, contribute to intercellular communication. We previously reported that cholangiocyte-derived exosomal long noncoding RNA (lncRNA) H19 plays a vital role in disrupting bile acid homeostasis in hepatocytes and promoting the activation of hepatic stellate cells (HSCs). Exosomal H19 derived from cholangiocytes was rapidly taken up by Kupffer cells. However, the mechanistic links between exosomal lncRNA H19 and macrophage-driven inflammation in cholestasis remain unclear. Here, we reported that the hepatic H19 level was closely correlated with macrophage activation and hepatic fibrosis in both Mdr2-/- and bile duct ligation (BDL) cholestatic mouse models, as well as in human primary sclerosing cholangitis (PSC) and primary biliary cholangitis (PBC) patients. Exosomal H19 significantly induced the expression and secretion of chemokine (C–C motif) ligand 2 (CCL-2) and interleukin 6 (IL-6) in Kupffer cells. H19-enriched exosomes enhanced the activation M1 polarization of Kupffer cells and promoted the recruitment and differentiation of bone marrow-derived macrophages, which were inhibited by a CCL-2 pharmacological inhibitor. In conclusion, Cholangiocyte-derived exosomal H19 played a critical role in macrophage activation, differentiation, and chemotaxis through CCL-2/CCR-2 signaling pathways, which represent a therapeutic target for cholestatic liver diseases.

scholarly journals Polarization of M2 macrophages requires Lamtor1 that integrates cytokine and amino-acid signals

2016 ◽  
Vol 7 (1) ◽  
Author(s):  
Tetsuya Kimura ◽  
Shigeyuki Nada ◽  
Noriko Takegahara ◽  
Tatsusada Okuno ◽  
Satoshi Nojima ◽  
...  
Keyword(s):  
Amino Acid ◽  
Macrophage Activation ◽  
Adaptor Protein ◽  
M2 Macrophages ◽  
Downstream Target ◽  
Mechanistic Target Of Rapamycin ◽  
M2 Polarization ◽  
M1 Polarization ◽  
Amino Acid Sensing ◽  
M1 And M2 Macrophages

Abstract Macrophages play crucial roles in host defence and tissue homoeostasis, processes in which both environmental stimuli and intracellularly generated metabolites influence activation of macrophages. Activated macrophages are classified into M1 and M2 macrophages. It remains unclear how intracellular nutrition sufficiency, especially for amino acid, influences on macrophage activation. Here we show that a lysosomal adaptor protein Lamtor1, which forms an amino-acid sensing complex with lysosomal vacuolar-type H+-ATPase (v-ATPase), and is the scaffold for amino acid-activated mTORC1 (mechanistic target of rapamycin complex 1), is critically required for M2 polarization. Lamtor1 deficiency, amino-acid starvation, or inhibition of v-ATPase and mTOR result in defective M2 polarization and enhanced M1 polarization. Furthermore, we identified liver X receptor (LXR) as the downstream target of Lamtor1 and mTORC1. Production of 25-hydroxycholesterol is dependent on Lamtor1 and mTORC1. Our findings demonstrate that Lamtor1 plays an essential role in M2 polarization, coupling immunity and metabolism.

scholarly journals Comparison between Peritoneal Macrophage Activation by Bougainvillea xbuttiana Extract and LPS and/or Interleukins

2017 ◽  
Vol 2017 ◽  
pp. 1-11 ◽  
Author(s):  
Lluvia Arteaga Figueroa ◽  
Rodolfo Abarca-Vargas ◽  
Claudia García Alanis ◽  
Vera L. Petricevich
Keyword(s):  
Hydrogen Peroxide ◽  
Cytotoxic Effect ◽  
Macrophage Activation ◽  
Peritoneal Macrophages ◽  
Immunomodulatory Activity ◽  
Hydrogen Peroxide Production ◽  
Griess Reagent ◽  
Violet Crystal ◽  
Low Cytotoxicity

Activation of macrophages may be one of the possible approaches in modulating inflammation. We previously reported that Bougainvillea xbuttiana extract showed an immunomodulatory activity. Here we compare the activation of macrophages exposed to B. xbuttiana extract and compare it with the other treatments such as LPS, IL-4, and IL-10. The cytotoxic effect of extract on peritoneal macrophages was determined by the technique of violet crystal staining. To verify the activation of macrophages we used the tests of vacuolization, hydrogen peroxide production, and percentages of cellular expansion and phagocytosis. The levels of interleukins secreted by macrophages treated with the extract, LPS, and cytokines were determined by the biological assay for the determination of TNF levels and by ELISA for all other interleukins. NO levels were evaluated by colorimetric reactions using Griess reagent. Our results showed that B. xbuttiana extract induced (a) low cytotoxicity percentages, (b) increased vacuolization, hydrogen peroxide production and cell expansion and phagocytosis percentages, and (c) decreased production of TNF-α, IFN-γ, IL-1β, and IL-6 and potentiated production of IL-4, IL-10 and TGF-β. These results suggest that B. xbuttiana extract was able to activate the murine macrophages in a manner similar to those macrophages exposed to IL-4 and IL-10.

scholarly journals Attenuation of Inflammation and Leptin Resistance by Pyrogallol-Phloroglucinol-6,6-Bieckol on in the Brain of Obese Animal Models

Nutrients ◽  
2019 ◽  
Vol 11 (11) ◽  
pp. 2773 ◽  
Author(s):  
Myeongjoo Son ◽  
Seyeon Oh ◽  
Junwon Choi ◽  
Ji Tae Jang ◽  
Chang Hu Choi ◽  
...  
Keyword(s):  
Adipose Tissue ◽  
Inflammatory Cytokines ◽  
Brain Inflammation ◽  
Leptin Resistance ◽  
Diet Induced Obesity ◽  
Leptin Sensitivity ◽  
M1 Polarization ◽  
Activated Macrophage ◽  
The Brain ◽  
Pro Inflammatory Cytokines

Obesity induces inflammation both in the adipose tissue and the brain. Activated macrophage infiltration, polarization of macrophages to a more inflammatory type (M1), and increased levels of pro-inflammatory cytokines are related to brain inflammation, which induces leptin resistance in the brain. Pyrogallol-phloroglucinol-6,6-bieckol (PPB), a compound from Ecklonia cava, has anti-inflammatory effects. In this study, we evaluated the effects of PPB effect M1 polarization and inflammation and its ability to restore the effects of leptin, such as a decrease in appetite and body weight. We administered PPB to diet-induced obesity (DIO) and leptin-deficient (ob/ob) mice, evaluated macrophage activation, polarization, and changes of inflammatory cytokine level in adipose tissue and brain, and determined the effect of PPB on leptin resistance or leptin sensitivity in the brain. The levels of activated macrophage marker, M1/M2, and pro-inflammatory cytokines were increased in the adipose tissue and brain of DIO and ob/ob mice than control. TLR4 expression, endoplasmic reticulum (ER) stress, and NF-κB expression in the brain of DIO and ob/ob mice were also increased; this increase was related to the upregulation of SOCS3 and decreased phosphorylated STAT3, which decreased leptin sensitivity in the brain. PPB decreased inflammation in the brain, restored leptin sensitivity, and decreased food intake and weight gain in both DIO and ob/ob mice.

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