Innate immune sensing of influenza A virus (IAV) induces activation of various immune effector mechanisms including the NLRP3 inflammasome and programmed cell death pathways. Although type I IFNs are identified as key mediators of inflammatory and cell death responses during IAV infection, the involvement of various IFN-regulated effectors in facilitating these responses are less studied. Here, we demonstrate the role of interferon regulatory factor 1 (IRF1) in promoting NLRP3 inflammasome activation and cell death during IAV infection. IRF1 functions as a transcriptional regulator of Z-DNA binding protein 1 (ZBP1, also called as DLM1/DAI), a key molecule mediating IAV-induced inflammatory and cell death responses. Therefore, our study identified IRF1 as an upstream regulator of NLRP3 inflammasome and cell death during IAV infection and further highlights the complex and multilayered regulation of key molecules controlling inflammatory response and cell fate decisions during infections.
IRF1 Is a Transcriptional Regulator of ZBP1 Promoting NLRP3 Inflammasome Activation and Cell Death during Influenza Virus Infection.
Specimen part
View SamplesLysosomal cathepsins regulate an exquisite range of biological functions, and their deregulation is associated with inflammatory, metabolic and degenerative disease in humans. Here, we identified a key cell-intrinsic role for cathepsin B as a negative feedback regulator of lysosomal biogenesis and autophagy. Mice and macrophages lacking cathepsin B activity had increased resistance to the cytosolic bacterial pathogen Francisella novicida. Genetic deletion or pharmacological inhibition of cathepsin B downregulated mTOR activity and prevented cleavage of the lysosomal calcium channel TRPML1. These events drove transcription of lysosomal and autophagy genes via the transcription factor TFEB, which increased lysosomal biogenesis and activation of autophagy-initiation kinase ULK1 for clearance of the bacteria. Our results identified a fundamental biological function of cathepsin B in providing a checkpoint for homeostatic maintenance of lysosome population and basic recycling functions in the cell.
Cathepsin B modulates lysosomal biogenesis and host defense against Francisella novicida infection.
Specimen part
View SamplesInflammasome activation is critical for host defense against various microbial infections. Activation of the NLRC4 inflammasome requires detection of flagellin or type III secretion system (T3SS) components by NLR family apoptosis inhibitory proteins (NAIPs); yet how this pathway is regulated is unknown. Here we found that interferon regulatory factor 8 (IRF8) is required for optimal activation of the NLRC4 inflammasome in bone marrow-derived macrophages infected with Salmonella Typhimurium, Burkholderia thailandensis, or Pseudomonas aeruginosa but is dispensable for activation of the canonical and non-canonical NLRP3, AIM2, and Pyrin inflammasomes. IRF8 governs the transcription of Naips to allow detection of flagellin or T3SS proteins to mediate NLRC4 inflammasome activation. Furthermore, we found that IRF8 confers protection against bacterial infection in vivo, owing to its role in inflammasome-dependent cytokine production and pyroptosis. Altogether, our findings suggest that IRF8 is a critical regulator of NAIPs and NLRC4 inflammasome activation for defense against bacterial infection.
IRF8 Regulates Transcription of Naips for NLRC4 Inflammasome Activation.
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View SamplesRegulatory T (Treg) cell activation and expansion during neonatal life and in response to inflammation are critical for immunosuppression, yet the mechanisms governing these events are incompletely understood. We report that the oncogene and transcriptional regulator c-Myc (Myc) controls immune homeostasis through regulation of Treg cell accumulation and functional activation. Myc activity is enriched in Treg cells generated during neonatal life and responding to inflammation. Myc-deficient Treg cells show cell-intrinsic defects in overall accumulation and ability to transition to an activated state during early life or acute inflammation. Consequently, loss of Myc in Treg cells results in a rapid, early-onset autoimmune disorder accompanied by uncontrolled effector CD4+ and CD8+ T cell responses. We also provide evidence that Myc regulates mitochondrial oxidative metabolism but is dispensable for fatty acid oxidation (FAO). Indeed, Treg cell-specific deletion of Cox10, which is required for oxidative phosphorylation, but not Cpt1a, the rate-limiting enzyme for FAO, results in impaired Treg cell function and maturation. Thus, Myc coordinates Treg cell accumulation, transitional activation and metabolic programming to orchestrate immune homeostasis.
Homeostasis and transitional activation of regulatory T cells require c-Myc.
Specimen part
View SamplesEwings sarcoma is highly malignant bone tumor that involves childhood and adolescent, and its nature has not been well understood. To clarify its cellular origin and the mechanisms of tumorigenesis, we used ex vivo approach to create a murine model for Ewings sarcoma. The osteochondrogenic progenitors derived from the embryonic superficial zone (eSZ, designated as FZ in the data set) of murine long bones at late gestation were purified by microdissection, introduced with EWS-FLI1 or EWS-ERG retroviruses and transplanted into nude mice. Ewings sarcoma-like small round cell sarcoma developed at 100% penetrance, whereas tumor induction was less effective when growth place (GP)-derived cells were used. The different response of gene expression to EWS-FLI1 between eSZ and GP cells suggests importance of the specific cellular context for EWS-FLI1 to induce Ewings sarcoma. The Wnt/-catenin pathway was involved in close relationship to the cellular context, with Dkk2 and Wipf1 as important downstream modulators. Furthermore, gene expression profiling revealed similarity between our models and human Ewings sarcoma. These results indicate that Ewings sarcoma originates from the embryonic osteochondrogenic progenitor.
Ewing's sarcoma precursors are highly enriched in embryonic osteochondrogenic progenitors.
Specimen part, Time
View SamplesEwings sarcoma is highly malignant bone tumor that involves childhood and adolescent, and its nature has not been well understood. To clarify its cellular origin and the mechanisms of tumorigenesis, we used ex vivo approach to create a murine model for Ewings sarcoma. The osteochondrogenic progenitors derived from the facial zone (FZ) of murine long bones at late gestation were purified by microdissection, introduced with EWS-FLI1 or EWS-ERG retroviruses and transplanted into nude mice. Ewings sarcoma-like small round cell sarcoma developed at 100% penetrance, whereas tumor induction was less effective when growth place (GP)-derived cells were used. The different response of gene expression to EWS-FLI1 between FZ and GP cells suggests importance of the specific cellular context for EWS-FLI1 to induce Ewings sarcoma. The Wnt/-catenin pathway was involved in close relationship to the cellular context, with Dkk2 and Wipf1 as important downstream modulators. Furthermore, gene expression profiling revealed similarity between our models and human Ewings sarcoma. These results indicate that Ewings sarcoma originates from the embryonic osteochondrogenic progenitor.
Ewing's sarcoma precursors are highly enriched in embryonic osteochondrogenic progenitors.
Specimen part
View SamplesThe in-vitro analysis of the hypomethylation of the imprinting control region 1 (ICR1) within the IGF2/H19 locus is challenged by the mosaic distribution of the epimutation in tissues from children with Silver-Russell syndrome (SRS).
Decreased expression of cell proliferation-related genes in clonally derived skin fibroblasts from children with Silver-Russell syndrome is independent of the degree of 11p15 ICR1 hypomethylation.
Specimen part, Disease
View SamplesIschemia/reperfusion injuries is a known complication to hepatic surgery. Ischemic pre- (IPC) and postconditioning (IPO) protects the liver against ischemia/reperfusion-injuries. Expression profiling were performed on liver biopsies seeking to identify molecular mediators of the protective properties.
Ischemic pre- and postconditioning has pronounced effects on gene expression profiles in the rat liver after ischemia/reperfusion.
Sex
View SamplesPhosphatidylcholine transfer protein (PC-TP, a.k.a StarD2) is abundantly expressed in liver and is regulated by PPAR. When fed the synthetic PPAR ligand fenofibrate, Pctp-/- mice exhibited altered lipid and glucose homeostasis. Microarray profiling of liver from fenofibrate fed wild type and Pctp-/- mice revealed differential expression of a broad array of metabolic genes, as well as their regulatory transcription factors. Because its expression controlled the transcriptional activities of both PPAR and HNF4 in cell culture, the broader impact of PC-TP on nutrient metabolism is most likely secondary to its role in fatty acid metabolism.
Regulatory role for phosphatidylcholine transfer protein/StarD2 in the metabolic response to peroxisome proliferator activated receptor alpha (PPARalpha).
Sex, Age, Specimen part
View SamplesThis SuperSeries is composed of the SubSeries listed below.
NALP3 inflammasome upregulation and CASP1 cleavage of the glucocorticoid receptor cause glucocorticoid resistance in leukemia cells.
Disease, Cell line, Treatment
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