Project description:The use of glucocorticoids (GCs), which bind and activate the glucocorticoid receptor (GR), in systemic inflammatory response syndromes (SIRS) is disputed. Mice with a poor transcriptional response of dimer-dependent GR target genes were studied in a model of TNF-induced SIRS. These GR dim/dim mice display a significant increase in TNF sensitivity and a lack of protection by the GC dexamethasone (DEX). Unchallenged GR dim/dim mice have a strong interferon-stimulated gene (ISG) signature at the transcriptional level and this ISG signature is gut specific. Here, we used shotgun proteomics to study the regulation of ISG proteins in the ileum of GR dim/dim mice. Our data showed that unchallenged GR dim/dim mice have a strong interferon-stimulated gene (ISG) signature, along with STAT1 upregulation. Taken together, we show that GR dim/dim mice poorly control ISG expression resulting in excessive necroptosis induction by TNF. Our findings support a critical interplay between gut microbiota, interferons, necroptosis and GR in both the basal response to acute inflammatory challenges and in the pharmacological intervention by GCs.
Project description:Under conditions of erythrolytic stress, which accompanies many disease states, macrophages play key roles in phagocytosing damaged RBCs and preventing the toxic effects of cell-free hemoglobin and heme to maintain homeostasis. Using a genetic mouse model of spherocytosis and single-cell RNA sequencing, we show that erythrolytic stress promotes expansion of a specific macrophage population in the liver (which we named “erythrophagocytes”) expressing high levels of Marco and Hmox1 and low levels of MHC class II related genes with an anti-inflammatory gene expression signature. We confirmed the strong anti-inflammatory function of erythrophagocytes in two models of sterile inflammatory liver disease: anti-CD40 antibody-induced systemic inflammation syndrome with necrotizing hepatitis and diet-induced nonalcoholic fatty liver disease (NAFLD). The unique anti-inflammatory phenotype and function of erythrophagocytes was reproduced in vitro by heme-exposure of mouse macrophages, yielding a transcriptional profile that segregated heme-polarized from classical M1- and M2-polarized cells. Mapping transposase-accessible chromatin in single cells using sequencing (scATAC-seq) suggested NFE2L2/NRF2 as a critical driver of anti-inflammatory erythrophagocytes in the livers of hemolytic mice and heme-suppression of the inflammatory response was abolished in macrophages from Nfe2l2/Nrf2-deficient animals. Our findings point to a novel pathway that regulates macrophage functions to link RBC homeostasis and heme metabolism with innate immunity.
Project description:<p>Hepatoblastoma (HB) is the most common pediatric liver tumor, affecting mostly children under 3 years of age. This rare tumor represents 1% of all pediatric cancers. Genetic studies have shown that HB is characterized by high frequency mutations of the CTNNB1 gene encoding beta-catenin (around 75%) and relative genomic stability. Here we have analyzed the transcriptional profile of 21 HBs compared to matched non-tumor livers by Cap Analysis of Gene Expression (CAGE), which provides accurate and quantitative profiling of all transcripts. CAGE analysis revealed strong upregulation of known Wnt target coding genes in most tumors analyzed, consistent with previous transcriptomic studies. To better define the Wnt-dependent transcriptional landscape of HB, we integrated CAGE data with TCF4 ChIP-seq data from a CTNNB1-mutated cancer cell line and with the FANTOM5 genomic coordinates of TCF/LEF binding motifs. Both TCF/LEF binding motifs and ChIP-seq peaks were strongly enriched in the immediate upstream region, not only for protein-coding genes, but also for non-coding transcripts. Among the selected 112 top Wnt target genes at FDR<1.0E-6 and fold change>8, we found clear over-representation (66%) of distant transcription start sites (TSSs) representing lncRNAs and enhancer RNAs, which raises the question of their role in HB pathogenesis. Analysis of the 112 promoters using CAGEd-oPOSSUM confirmed the predominant involvement of Tcf/Lef transcription factors, together with HNF4G, GATA2, Sox3 and Ets-related genes. Finally, the 112 Wnt target signature defined 3 tumor subclasses, T1, T2 and T3, characterized by progressive alteration of the non-coding part of the transcriptome and significant differences in clinical behavior.</p>
Project description:Under conditions of erythrolytic stress, which accompanies many disease states, macrophages play key roles in phagocytosing damaged RBCs and preventing the toxic effects of cell-free hemoglobin and heme to maintain homeostasis. Using a genetic mouse model of spherocytosis and single-cell RNA sequencing, we show that erythrolytic stress promotes expansion of a specific macrophage population in the liver (which we named “erythrophagocytes”) expressing high levels of Marco and Hmox1 and low levels of MHC class II related genes with an anti-inflammatory gene expression signature. We confirmed the strong anti-inflammatory function of erythrophagocytes in two models of sterile inflammatory liver disease: anti-CD40 antibody-induced systemic inflammation syndrome with necrotizing hepatitis and diet-induced nonalcoholic fatty liver disease (NAFLD). The unique anti-inflammatory phenotype and function of erythrophagocytes was reproduced in vitro by heme-exposure of mouse macrophages, yielding a transcriptional profile that segregated heme-polarized from classical M1- and M2-polarized cells. The phenotype of anti-inflammatory erythrophagocytes coincided with NFE2L2/NRF2 driven gene expression and was abolished in Nfe2l2/Nrf2-deficient macrophages. Our findings point to a novel pathway that regulates macrophage functions to link RBC homeostasis and heme metabolism with innate immunity.
Project description:Under conditions of erythrolytic stress, which accompanies many disease states, macrophages play key roles in phagocytosing damaged RBCs and preventing the toxic effects of cell-free hemoglobin and heme to maintain homeostasis. Using a genetic mouse model of spherocytosis and single-cell RNA sequencing, we show that erythrolytic stress promotes expansion of a specific macrophage population in the liver (which we named “erythrophagocytes”) expressing high levels of Marco and Hmox1 and low levels of MHC class II related genes with an anti-inflammatory gene expression signature. We confirmed the strong anti-inflammatory function of erythrophagocytes in two models of sterile inflammatory liver disease: anti-CD40 antibody-induced systemic inflammation syndrome with necrotizing hepatitis and diet-induced nonalcoholic fatty liver disease (NAFLD). The unique anti-inflammatory phenotype and function of erythrophagocytes was reproduced in vitro by heme-exposure of mouse macrophages, yielding a transcriptional profile that segregated heme-polarized from classical M1- and M2-polarized cells. The phenotype of anti-inflammatory erythrophagocytes coincided with NFE2L2/NRF2 driven gene expression and was abolished in Nfe2l2/Nrf2-deficient macrophages. Our findings point to a novel pathway that regulates macrophage functions to link RBC homeostasis and heme metabolism with innate immunity.
Project description:Under conditions of erythrolytic stress, which accompanies many disease states, macrophages play key roles in phagocytosing damaged RBCs and preventing the toxic effects of cell-free hemoglobin and heme to maintain homeostasis. Using a genetic mouse model of spherocytosis and single-cell RNA sequencing, we show that erythrolytic stress promotes expansion of a specific macrophage population in the liver (which we named “erythrophagocytes”) expressing high levels of Marco and Hmox1 and low levels of MHC class II related genes with an anti-inflammatory gene expression signature. We confirmed the strong anti-inflammatory function of erythrophagocytes in two models of sterile inflammatory liver disease: anti-CD40 antibody-induced systemic inflammation syndrome with necrotizing hepatitis and diet-induced nonalcoholic fatty liver disease (NAFLD). The unique anti-inflammatory phenotype and function of erythrophagocytes was reproduced in vitro by heme-exposure of mouse macrophages, yielding a transcriptional profile that segregated heme-polarized from classical M1- and M2-polarized cells. The phenotype of anti-inflammatory erythrophagocytes coincided with NFE2L2/NRF2 driven gene expression and was abolished in Nfe2l2/Nrf2-deficient macrophages. Our findings point to a novel pathway that regulates macrophage functions to link RBC homeostasis and heme metabolism with innate immunity.
Project description:Under conditions of erythrolytic stress, which accompanies many disease states, macrophages play key roles in phagocytosing damaged RBCs and preventing the toxic effects of cell-free hemoglobin and heme to maintain homeostasis. Using a genetic mouse model of spherocytosis and single-cell RNA sequencing, we show that erythrolytic stress promotes expansion of a specific macrophage population in the liver (which we named “erythrophagocytes”) expressing high levels of Marco and Hmox1 and low levels of MHC class II related genes with an anti-inflammatory gene expression signature. We confirmed the strong anti-inflammatory function of erythrophagocytes in two models of sterile inflammatory liver disease: anti-CD40 antibody-induced systemic inflammation syndrome with necrotizing hepatitis and diet-induced nonalcoholic fatty liver disease (NAFLD). The unique anti-inflammatory phenotype and function of erythrophagocytes was reproduced in vitro by heme-exposure of mouse macrophages, yielding a transcriptional profile that segregated heme-polarized from classical M1- and M2-polarized cells. The phenotype of anti-inflammatory erythrophagocytes coincided with NFE2L2/NRF2 driven gene expression and was abolished in Nfe2l2/Nrf2-deficient macrophages. Our findings point to a novel pathway that regulates macrophage functions to link RBC homeostasis and heme metabolism with innate immunity.
Project description:Aging is characterized by a chronic low-grade inflammation in multiple tissues, also termed as “inflammaging”, which represents a significant risk factor for many aging-related chronic diseases. However, the mechanisms and regulatory networks behind inflammaging across different tissues have not been fully elucidated. Here, by profiling transcriptomes and epigenomes of the kidney and liver from young and aged mice, we found that activation of inflammatory response was the conserved signature across tissues. Through integrative analysis, we revealed links between transcriptome change and chromatin dynamics, and identified AP-1 and ETS family transcription factors (TFs) were potential regulators of inflammaging. Further in-situ validation showed AP-1 was mainly activated in aged hepatic and renal cells, while enhanced ETS was almost caused by elevated infiltration of macrophages, indicating these TFs had different mechanisms in inflammaging. Functional data showed genetic knockdown of Fos, a major member of AP-1, significantly attenuated inflammatory response in aged kidneys and livers. Taken together, our analysis revealed conserved signatures and regulatory TFs of inflammaging in the kidney and liver, providing novel targets for the development of anti-aging interventions.
Project description:Diclofenac (DCL) is a non-steroidal anti-inflammatory drug. Its use can be associated with serious adverse drug reactions most notable myocardial infarction and drug-induced liver injury (DILI). The molecular causes leading to DILI remains unclear and it seems to be multifactorial. The aims of this study is to identify the molecular mechanisms involving immune mediated inflammatory reactions and its link to DILI through whole genome gene expression profiling. Diclofenac was given to mice at 30 mg/kg for 1, 3 and 14 days. Microarray experiments were performed with RNA extracts from liver samples. The performed gene expression studies showed >600 significantly regulated genes after single and repeated dosing for 3 and 14 days. The functional annotation revealed several genes were regulated in common coding for inflammatory, immune, stress and acute-phase responses. Immunohistochemistry, qRT-PCR as well as Western blotting were performed to evidence the regulation of key molecules in affected livers. In conclusion, the present study provides evidence for a mechanism of diclofenac induced liver injury that involves pro-inflammatory cytokine and acute phase responses. C57BL6- mice (males, 8 weeks old) (n=5) were administered daily by intraperitoneal injection of 30 mg/kg diclofenac sodium for up to 14 days. Control mice (n=5) were treated corresponding quantities of saline. The mice were euthanized at 24h (day 1), 72h (day 3) or 14 days after vehicle or diclofenac administration. The whole genome gene expression profiling studies of liver samples were performed to define the molecular mechanism of diclofenac induced immune mediated liver injury.
Project description:Treating samples with anti-CD40, and antibiotics to establish what transcriptional impact antibiotics is having. Anti-CD40 was found to induce a strong inflammatory signature. Antibiotics in combination with anti-CD40 attenuated this resulting in a much improved phenotype. However the detectable transcriptional differences were somewhat modest.