Project description:Metabolic reprogramming during macrophage polarization supports the effector functions of these cells in health and disease. Although the importance of glycolytic and oxidative metabolism in M1 and M2 macrophages, respectively, is well established, our knowledge of metabolic checkpoints controlling these effector states is limited. Here we demonstrate that pyruvate dehydrogenase kinase (PDK), which inhibits the conversion of cytosolic pyruvate to mitochondrial acetyl-CoA by pyruvate dehydrogenase, functions as a metabolic checkpoint in M1 macrophages. Genetic deletion or pharmacological inhibition of PDK2/4 prevents polarization of macrophages to the M1 phenotype in response to inflammatory stimuli (lipopolysaccharide plus IFN-γ). The therapeutic potential of attenuation of pro-inflammatory responses by PDK inhibition was tested, both genetically and pharmacologically, in obesity-induced insulin resistance, a disease process in which M1 macrophages contribute to adipose tissue inflammation and insulin resistance. Taken together, these studies identify PDK2/4 as a metabolic checkpoint for M1 phenotype polarization of macrophages.
Project description:Macrophages are key inflammatory immune cells in Behcet’s disease (BD) and BD serum may contribute to macrophages’ hyperactivation in BD. To further investigate the role of BD serum on the phenotypes and functions of macrophages, we performed next generation sequencing-based genome-wide transcriptional profiling on BD serum or healthy control (HC) serum treated macropahges.
Project description:Macrophages are effector cells of the innate immune system and undergo phenotypical changes in response to organ injury and repair. They are most often classified as proinflammatory M1 and anti-inflammatory M2 macrophages. Protein arginine deiminase (PAD) enzymes, that catalyze the conversion of protein-bound arginine into citrulline, an irreversible posttranslational modification, are expressed in macrophages. However, the substrate scope of the PADs and their role in the immune cells remain not well defined. This study aims to investigate the role of PADs in the THP-1 macrophage polarization to M1 and M2 phenotype and identify the citrullinated proteins, and the modified Arg that are associated with this biological switch using mass spectrometry. Our study showed that PAD2, and to a lesser extent PAD1 and PAD4 were dominantly expressed in M1 macrophages. We showed that inhibiting PADs by BB-Cl-amidine decreased the macrophage’s polarization to M1 and increased to M2 phenotype. The process was mediated by the downregulation of proteins involved in NF-kβ pathway. Silencing of PAD2 confirmed activation to M2 macrophages through upregulation of the antiviral innate immune response and interferon signaling. 192 novel citrullination sites that belong to inflammation, cell death and DNA/RNA processing pathways were identified in M1 and M2 macrophages.
Project description:Obesity-associated insulin resistance is characterized by a state of chronic, low-grade inflammation that is associated with the accumulation of M1 proinflammatory macrophages in adipose tissue. Although different evidence explains the mechanisms linking the expansion of adipose tissue and adipose tissue macrophage (ATM) polarization, in the current study we investigated the concept of lipid-induced toxicity as the pathogenic link that could explain the trigger of this response. We addressed this question using isolated ATMs and adipocytes from genetic and diet-induced murine models of obesity. Through transcriptomic and lipidomic analysis, we created a model integrating transcript and lipid species networks simultaneously occurring in adipocytes and ATMs and their reversibility by thiazolidinedione treatment. We show that polarization of ATMs is associated with lipid accumulation and the consequent formation of foam cell–like cells in adipose tissue. Our study reveals that early stages of adipose tissue expansion are characterized by M2-polarized ATMs and that progressive lipid accumulation within ATMs heralds the M1 polarization, a macrophage phenotype associated with severe obesity and insulin resistance. Furthermore, rosiglitazone treatment, which promotes redistribution of lipids toward adipocytes and extends the M2 ATM polarization state, prevents the lipid alterations associated with M1 ATM polarization. Our data indicate that the M1 ATM polarization in obesity might be a macrophage-specific manifestation of a more general lipotoxic pathogenic mechanism. This indicates that strategies to optimize fat deposition and repartitioning toward adipocytes might improve insulin sensitivity by preventing ATM lipotoxicity and M1 polarization. 15 samples; 2 genotypes and 2 time points
Project description:Classically (M1) and alternatively activated (M2) macrophages play distinct roles in various physiological and disease processes. Understanding the gene transcription programs that contribute to macrophage polarization along the M1/M2 spectrum may lead to new tools to detect and therapeutically manipulate macrophage phenotype. Here, we define the M1 and M2 macrophage signature through mRNA microarray. The M1 macrophage signature was defined by 629 up-regulated and 732 down-regulated genes while the M2 macrophage signature was formed by 388 up-regulated and 425 down-regulated genes. While a subset of probes was common to both M1 and M2 cells, others were exclusive to each macrophage subset. The common M1/M2 pathways were characterized by changes in various transcriptional regulators and signaling partners, including increases in Kruppel-like Factor (Klf) 4, but decreases in Klf2. To identify M1 and M2 biomarkers that help discriminate these populations, we selected genes that were increased during M1 or M2 differentiation but decreased in the opposite population. Among top novel M1-distinct genes, we identified CD38, G-protein coupled receptor 18 (Gpr18) and Formyl peptide receptor 2 (Fpr2). Among top M2 genes, we found early growth response protein 2 (Egr2) and Myc. We validated these genes by Real-Time PCR and developed a CD38/Egr2-based flow cytometry assay that discriminates between M1 and M2 macrophages. Overall, this work defines the M1 and M2 signature and identifies several novel M1 and M2 genes that may be used to distinguish and manipulate M1 and M2 macrophages. Total RNA was prepared from bone marrow-derived macrophages of wild-type mice (n=2-3 independent mice) treated in M0, M1 or M2 conditions (n=2-3 replicates per condition originating from different mice)
Project description:The proteasome is a central regulatory hub for intracellular signaling by degrading numerous signaling mediators. Immunoproteasomes are specialized types of proteasomes known to be involved in shaping adaptive immune responses, but their role for innate immune signaling is elusive. Here, we analyzed immunoproteasome function for polarization of alveolar macrophages which are highly specialized tissue macrophages of the alveolar surface of the lung. Classical activation (M1 polarization) of primary alveolar macrophages by LPS/IFNγ transcriptionally induced all three immunoproteasome subunits LMP2, LMP7, and MECL-1. In contrast, IL-4 triggered alternative (M2) activation was accompanied by posttranscriptional upregulation of LMP2 and LMP7. Accordingly, immunoproteasome activity increased in M1 cells, and to some extent under M2 conditions. Analyzing the polarization capability from LMP7 deficient mice revealed no effect on the LPS/IFNγ triggered M1 profile, but uncovered a distorted M2 profile for IL-4 stimulated LMP7-/- alveolar macrophages as characterized by increased M2 marker gene expression and CCL17 cytokine release. This shift in immunoproteasome-dependent M2 polarization was accompanied by amplified AKT/STAT6 activation and IRF4 expression in LMP7-/- alveolar macrophages. IL-13 stimulation of LMP7 deficient cells induced a similar M2 skewed profile and IL4Rα protein expression was generally elevated in LMP7-/- alveolar macrophages, indicating that amplified IL4R signaling in immunoproteasome defective cells may contribute to augmented M2 polarization. Importantly, treatment with an LMP7-specific proteasome inhibitor recapitulated the findings of genetic LMP7 inactivation. Our results thus suggest a novel role of immunoproteasome function for regulating innate immune function of macrophages by limiting IL4R expression and signaling. Expression data of M0 and M2 macrophages derived from Lmp7 k.o. and control animals
Project description:Chronic obstructive pulmonary disease (COPD) stands as the prevailing chronic airway ailment, characterized by chronic bronchitis and emphysema. Current medications fall short in treatment of these diseases, underscoring the urgent need for effective therapy. Prior research indicated immunoproteasome inhibition can alleviate various inflammatory diseases by modulating immune cell functions. However, its therapeutic potential in COPD remains largely unexplored. Here, we observed elevated expression of immunoproteasome subunits LMP2 and LMP7 in bronchoalveolar lavage (BAL) macrophages collected from mouse with LPS/elastase-induced emphysema and M1 polarized macrophages in vitro. Subsequently, intranasal administration of the immunoproteasome-specific inhibitor ONX-0914 significantly mitigated emphysema-associated airway inflammation and improved lung function in mice, by suppressing M1 macrophage polarization. Mechanistically, ONX-0914 activated autophagy, and endoplasmic reticulum (ER) stress was not necessary for ONX- 0914-induced M1 suppression. Intriguingly, ONX-0914 upregulated the autophagy receptor p62/SQSTM1, which proved vital for the inhibitory effect of ONX-0914 on M1 polarization. Additionally, our research identified that the nuclear factor erythroid 2-related factor-2 (NRF2), but not NRF1, was responsible for the induction of p62. Finally, silencing both NRF1 and NRF2 partially counteracted ONX-0914-mediated M1 polarization inhibition. In summary, our findings suggest that targeting the immunoproteasome in macrophages holds promise as a therapeutic strategy for emphysema.
Project description:To study the effect of iodide ions on the M1 polarization of macrophages, we chose the RAW264.7 cell line. We then performed gene expression profiling analysis using data obtained from RNA-seq of 3 different groups.
Project description:Chronic obstructive pulmonary disease (COPD) stands as the prevailing chronic airway ailment, characterized by chronic bronchitis and emphysema. Current medications fall short in treatment of these diseases, underscoring the urgent need for effective therapy. Prior research indicated immunoproteasome inhibition can alleviate various inflammatory diseases by modulating immune cell functions. However, its therapeutic potential in COPD remains largely unexplored. Here, we observed elevated expression of immunoproteasome subunits LMP2 and LMP7 in bronchoalveolar lavage (BAL) macrophages collected from mouse with LPS/elastase-induced emphysema and M1 polarized macrophages in vitro. Subsequently, intranasal administration of the immunoproteasome-specific inhibitor ONX-0914 significantly mitigated emphysema-associated airway inflammation and improved lung function in mice, by suppressing M1 macrophage polarization. Mechanistically, ONX-0914 activated autophagy, and endoplasmic reticulum (ER) stress was not necessary for ONX- 0914-induced M1 suppression. Intriguingly, ONX-0914 upregulated the autophagy receptor p62/SQSTM1, which proved vital for the inhibitory effect of ONX-0914 on M1 polarization. Additionally, our research identified that the nuclear factor erythroid 2-related factor-2 (NRF2), but not NRF1, was responsible for the induction of p62. Finally, silencing both NRF1 and NRF2 partially counteracted ONX-0914-mediated M1 polarization inhibition. In summary, our findings suggest that targeting the immunoproteasome in macrophages holds promise as a therapeutic strategy for emphysema.
Project description:Chronic obstructive pulmonary disease (COPD) stands as the prevailing chronic airway ailment, characterized by chronic bronchitis and emphysema. Current medications fall short in treatment of these diseases, underscoring the urgent need for effective therapy. Prior research indicated immunoproteasome inhibition can alleviate various inflammatory diseases by modulating immune cell functions. However, its therapeutic potential in COPD remains largely unexplored. Here, we observed elevated expression of immunoproteasome subunits LMP2 and LMP7 in bronchoalveolar lavage (BAL) macrophages collected from mouse with LPS/elastase-induced emphysema and M1 polarized macrophages in vitro. Subsequently, intranasal administration of the immunoproteasome-specific inhibitor ONX-0914 significantly mitigated emphysema-associated airway inflammation and improved lung function in mice, by suppressing M1 macrophage polarization. Mechanistically, ONX-0914 activated autophagy, and endoplasmic reticulum (ER) stress was not necessary for ONX- 0914-induced M1 suppression. Intriguingly, ONX-0914 upregulated the autophagy receptor p62/SQSTM1, which proved vital for the inhibitory effect of ONX-0914 on M1 polarization. Additionally, our research identified that the nuclear factor erythroid 2-related factor-2 (NRF2), but not NRF1, was responsible for the induction of p62. Finally, silencing both NRF1 and NRF2 partially counteracted ONX-0914-mediated M1 polarization inhibition. In summary, our findings suggest that targeting the immunoproteasome in macrophages holds promise as a therapeutic strategy for emphysema.