Project description:Specific gut microbiota is critically involved in metabolic diseases, including obesity. Through analysis of gut microbiota in diabetic patients and animal models, it was found that Romboutsia ilealis is closely associated with obesity. Here, our findings show that oral administration of Romboutsia ilealis significantly alleviates diet-induced obesity and metabolic dysfunction. Interestingly, this effect occurs not through modulation of food intake or energy expenditure, but by regulating lipid absorption and metabolism in the gut. Additionally, metabolomics analysis identified 2-oxindole-3-acetic acid (OAA) as the key metabolite involved in the regulation of obesity by Romboutsia ilealis. Its regulatory effect on intestinal lipid absorption was further validated both in vitro and in vivo. Mechanistically, using biotin-labeled OAA combined with proteomic analysis, we found that OAA directly interacts with the deubiquitin enzyme PSMD3, increasing the ubiquitination level of m6A binding protein YTHDF2 and reducing its protein stability, thereby enhancing intestinal lipid absorption. Furtherly, through m6A-seq, we discovered that YTHDF2 negatively regulates the expression of RXRB by recognizing the m6A sites on its mRNA, which in turn downregulates the expression of lipid absorption and transport proteins CD36 and FABP2, ultimately inhibiting intestinal lipid absorption. In summary, our findings reveal that Romboutsia ilealis and OAA regulate obesity-associated lipid accumulation through PSMD3-mediated deubiquitination of YTHDF2, suggesting that they represent novel prebiotics and probiotics with potential as therapeutic agents against obesity.
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: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.
Project description:Obesity is a chronic inflammatory disease that weakens macrophage innate immune response to infections. Since M1 polarization is crucial during acute infectious diseases, we hypothesized that diet-induced obesity inhibits M1 polarization of macrophages in the response to bacterial infection. Using a computational approach in conjunction with microarray data, we identified switching genes that may differentially control the behavior of response pathways in macrophages from lean and obese mice.
Project description:Obesity is a chronic inflammatory disease that weakens macrophage innate immune response to infections. Since M1 polarization is crucial during acute infectious diseases, we hypothesized that diet-induced obesity inhibits M1 polarization of macrophages in the response to bacterial infection. Using a computational approach in conjunction with microarray data, we identified switching genes that may differentially control the behavior of response pathways in macrophages from lean and obese mice. Bone marrow macrophages (BMMM-NM-&) from lean and obese mice were exposed to live Porphyromonas gingivalis (P. gingivalis) for three incubation times (1 h, 4 h and 24 h). cDNA from BMMM-NM-& of lean and obese mice were hybridized on Affymetrix Mouse Genome 430 2.0 Arrays. Hybridization was performed on three replicates at each time point (18 arrays total).
Project description:Macrophage polarization followed by acute myocardial infarction (MI) is essential for the regulation of inflammation and scar formation. Tripartite motif-containing protein 21 (TRIM21), a member of E3 ubiquitin ligases, is a crucial mediator in the process of inflammation and heart failure. However, the potential roles of TRIM21 in modulating post-MI inflammation and macrophage polarization remain elusive. We detected that the levels of TRIM21 were significantly reduced in macrophages of WT mice after MI. In contrast, MI was ameliorated in TRIM21 knockout (TRIM21-/-) mice with improved cardiac remodeling, characterized by a marked decrease in mortality, increased wall thickness, and improved cardiac function in comparison with wild-type (WT) MI mice. Importantly, TRIM21 deficiency decreased the post-MI apoptosis and DNA damage in the hearts of mice, and the accumulation of M1 phenotype macrophages in infarcted hearts significantly decreased in TRIM21-/- mice compared with WT controls. Mechanistically, depletion of TRIM21 orchestrated the process of M1 macrophage polarization via a PI3K/Akt signaling pathway. Overall, these data reveal that TRIM21 drives the inflammatory response and cardiac remodeling after MI via stimulating M1 macrophage polarization through a PI3K/Akt signaling pathway.
Project description:Pulmonary fibrosis (PF) is a terminal lung disease characterized by fibroblast proliferation, accumulation of extracellular matrix accumulation, inflammatory damage, and tissue structure destruction. The pathogenesis of this disease, especiallyparticularly idiopathic pulmonary fibrosis (IPF), is still remains unknown. Macrophages play a significant rolemajor roles in organ fibrosis diseases, including pulmonary fibrosis. The phenotype and polarization of macrophages are closely associated with the process of pulmonary fibrosis. A new direction in drug research on for antipulmonary fibrosis is focuseds on developing drugs that maintain the stability of the pulmonary microenvironment. Here, tThrough bioinformatics analysis and experiments involving bleomycininduced pulmonary fibrosis in mice, we confirmed the importance of macrophage polarization in IPF. The analysis revealed that macrophage polarization in IPF involves a change in the phenotypice spectrum. Furthermore, the experiments demonstrated showed high expression of M2-type macrophage-related-associated biomarkers and inducible nitric oxide synthase, thus indicating an imbalance in M1/M2 polarization of pulmonary macrophages in mice with pulmonary fibrosis. Our investigation revealed that the ethyl acetate extract (HG2) obtained from the roots of Prismatomeris connataPrismatomeris connata Y. Z. Ruan exhibits therapeutic efficacy against bleomycin-induced pulmonary fibrosis. HG2 demonstrates the ability to modulates macrophage polarization, alterations in the TGF‐β/Smads pSmad pathway, and downstream protein expression in the context of pulmonary fibrosis. Drawing upon On the basis of our findings, we believe that HG2 exhibits has potential as a novel component of traditional Chinese medicine component for treating pulmonary fibrosis.
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:In response to microenvironmental signals macrophages undergo different activation, indicated as classic/M1 and alternative/M2 polarization. C-Myc transcription factor could be an essential player in M2 polarization. Functional relevance of c-Myc in M2 macrophage biology is investigated by evaluating the effect of 100-58F4, on the transcriptional profile induced on human macrophages by IL-4. Human monocytes were obtained from normal donor buffy coats by two-step gradient centrifugation using Ficoll (Biochrom) and Percoll (Amersham). Non-adherent cells were discarded, and the purified monocytes were incubated for 7 days in RPMI 1640 (Biochom) supplemented with 10% FCS (HyClone) and 100 ng/mL M-CSF to obtain resting macrophages. Macrophage polarization was obtained by removing the culture medium and culturing cells in RPMI 1640 supplemented with 10% FCS and 100 ng/mL LPS plus 20 ng/mL IFN-gamma (M1 polarization) or 20 ng/mL IL-4 (M2 polarization) for 24 h. When needed, chemical inhibitors were added with IL-4.