NS1 proteins from avian influenza viruses like the 1918 pandemic NS1 are capable of inhibiting the key signaling integrator c-Abl (Abl1), resulting in massive cytopathic cell alterations. In the current study, we addressed the consequences of NS1-mediated alteration of c-Abl on acute lung injury and pathogenicity. Comparing isogenic strains that differ only in their ability to inhibit c-Abl, we observed elevated pathogenicity for the c-Abl-inhibiting virus. NS1-mediated block of c-Abl resulted in severe lung pathology and massive edema formation and facilitated secondary bacterial pneumonia. This phenotype was independent of differences in replication and immune responses, defining it as an NS1 virulence mechanism distinct from its canonical functions. Microarray analysis revealed extensive down-regulation of genes involved in cell integrity and vascular endothelial regulation. In conclusion, NS1 protein-mediated blockade of c-Abl signaling drives acute lung injury and primes for bacterial co-infections revealing potential insights into the pathogenicity of the 1918 pandemic virus.
Nonstructural protein 1 (NS1)-mediated inhibition of c-Abl results in acute lung injury and priming for bacterial co-infections: insights into 1918 H1N1 pandemic?
Specimen part, Time
View SamplesInfection is a major complication and cause of mortality and morbidity after acute stroke however the mechanisms are poorly understood. After experimental stroke the microarchitecture and cellular composition of the spleen are extensively disrupted resulting in deficits to immune function.
Experimental Stroke Differentially Affects Discrete Subpopulations of Splenic Macrophages.
Specimen part, Treatment
View SamplesWe have performed conditional inactivation of mef2c in the anterior heart field (AHF) of mice and observed a phenotypic spectrum of outflow tract anomalies in the conditional mutant hearts. In an effort to identify misregulated genes in the outflow tracts of the mutants, we have performed RNA-Seq on outflow tract samples dissected from E10.5 mutant and wild-type embryos. Overall design: There are four wild-type samples and four mutant samples.
MEF2C regulates outflow tract alignment and transcriptional control of Tdgf1.
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View SamplesTwo critical events that are required for normal transition from fetal to extrauterine life are development of the alveoli that allow for efficient gas exchange in the lung and relaxation of the pulmonary vascular smooth muscle. Patients with congenital diaphragmatic hernia (CDH) have abnormal lung and pulmonary vascular development that results in a lethal combination of lung hypoplasia and pulmonary hypertension. To better understand the mechanisms responsible for abnormal lung and pulmonary vascular development and function we generated Pbx1/2 conditional knockout mice that lack Pbx1 and Pbx2 expression in the lung mesenchyme. Pbx1 has previously been shown to be required for normal diaphragm development, however its role in alveologenesis, and the mechanisms responsible for pulmonary hypertension, has not been studied. We found that Pbx1/2 CKO mice have failure of alveologenesis and die of severe pulmonary hypertension by 2 to 3 weeks of age. In order to better understand the downstream genetic mis-regulation caused by deletion of Pbx1/2, and identify their potential transcriptional targets, we carried out transcriptional profiling of Pbx1/2 CKO and control mice starting at postnatal day 3 (P3), when a histological phenotype first becomes apparent, and then working back to the time of birth (P0), and embryonic day 14 (E14) when the pulmonary vascular smooth muscle is developing.
PBX transcription factors drive pulmonary vascular adaptation to birth.
Specimen part
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Divergent transcriptomic responses to aryl hydrocarbon receptor agonists between rat and human primary hepatocytes.
Sex, Age, Specimen part
View Samples(Abstract) Toxicogenomics has great potential for enhancing our understanding of environmental chemical toxicity, hopefully leading to better-informed human health risk assessments. This study employed toxicogenomic technology to reveal species differences in response to two prototypical aryl hydrocarbon receptor (AHR) agonists, 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) and the polychlorinated biphenyl (PCB) congener PCB 126. Dose responses of primary cultures of rat and human hepatocytes were determined using species-specific microarrays sharing over 4,000 gene orthologs. Forty-seven human and 79 rat genes satisfied dose response criteria for both chemicals and were subjected to further analysis including the calculation of EC50 and the relative potency (REP) of PCB 126 for each gene. Only 5 responsive orthologous genes were shared between the two species, yet the geometric mean of the REPs for all rat and human modeled responsive genes were 0.06 (95% Confidence Interval (CI); 0.03-0.1) and 0.002 (95% CI; 0.001-0.005), respectively, suggesting broad species differences in the initial events that follow AHR activation but precede toxicity. This indicates that there are species differences in both the specific genes that responded and the agonist potency and relative potency for those genes. This observed insensitivity of human cells to PCB 126 is consistent with more traditional measurements of AHR activation (i.e., CYP1A1 enzyme activity) and suggests that the species difference in PCB 126 sensitivity is likely due to certain aspects of AHR function. That a species divergence also exists in this expanded AHR-regulated gene repertoire is a novel finding and should help when extrapolating animal data to humans.
Divergent transcriptomic responses to aryl hydrocarbon receptor agonists between rat and human primary hepatocytes.
Sex, Age, Specimen part
View SamplesChronic exposure of Sprague-Dawley (SD) rats to either 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) or Aroclor 1254 results in female-selective induction of hepatic tumors. The relative potency of dioxins and PCB mixtures, such as Aroclor 1254, is often estimated using the internationally endorsed toxic equivalency (TEQ) approach. Comparing the genome wide changes in gene expression in both genders following exposure to toxic equivalent doses of these chemicals should identify critical sets of early response genes while further defining the concept of the TEQ of halogenated aromatic hydrocarbons. Aroclor 1254 at 0.6, 6.0 and 60 mg/kg body weight and TEQ doses of TCDD (0.3 and 3.0 g/kg), calculated to match the top two Aroclor 1254 doses, were orally administered to SD rats for three consecutive days. Day 4 gene expression in hepatic tissue was determined using microarrays. A linear mixed-effects statistical model was developed to analyze the data in relation to treatment, gender, and gender*treatment (G*T) interactions. The genes most changed included 54 genes with and 51 genes without a significant model G*T term. The known aryl hydrocarbon receptor (AHR) battery genes (Cyp1a1, Cyp1a2, Cyp1b1, Aldh3a1), and novel genes, responded in a TEQ dose-dependent manner in both genders. However, an important observation was the apparent disruption of sexually dimorphic basal gene expression, particularly for female rats. Since many of these genes are involved in steroid metabolism, exposure to either TCDD or Aroclor 1254 could disrupt proliferative signals more in female rats as a possible consequence of altered estrogen metabolism. This study extends the findings of previous rodent bioassays by identifying groups of genes, other than the well-characterized AHR response genes, whose disruption may be important in the tumorigenic mechanism in this rat strain.
Toxicogenomic analysis of gender, chemical, and dose effects in livers of TCDD- or aroclor 1254-exposed rats using a multifactor linear model.
Sex
View SamplesSV7tert AML cells were obtained from ATCC and cultured in Dulbecco's modified essential medium (DMEM), glutamine (4mmol) and 10% foetal bovine serum (FBS). Two million SV7tertAML cells were subcutaneously injected into nude mice either with or without subcutaneous oestrogen pellets (n=4 per group); oestrogen was added using 0.36mg 60 day release oestrogen pellets implanted sub-cutaneously. Mice were housed in pathoflex isolators at 26C, on 12 hour light / dark cycles. Irradiated RB2 diet and autoclaved water provided ad libertum.
Analysis of the oestrogen response in an angiomyolipoma derived xenograft model.
Specimen part
View SamplesThe Murphy Roth Large (MRL) mouse, a strain capable of regenerating right ventricular myocardium, has a high post-myocardial infarction (MI) survival rate compared with C57BL6/J (C57) mice. The biological processes responsible for this survival advantage are unknown.
Early postmyocardial infarction survival in Murphy Roths Large mice is mediated by attenuated apoptosis and inflammation but depends on genetic background.
Sex, Specimen part
View SamplesCell migration is central to many biological processes including embryonic development, wound healing, and cancer progression. Cell migration is sensitive to environmental stiffness, and many cell types exhibit a stiffness optimum at which migration is maximal. Here we present a cell migration simulator that predicts a stiffness optimum that can be shifted by altering the number of active molecular motors and clutches. This prediction is verified experimentally by comparing cell traction and F-actin retrograde flow for two cell types with differing amounts of active motors and clutches: embryonic chick forebrain neurons (ECFNs; optimum ~1 kPa) and U251 glioma cells (optimum ~100 kPa). In addition, the model predicts, and experiments confirm, that the stiffness optimum of U251 glioma cell migration, morphology, and F-actin retrograde flow rate can be shifted to lower stiffness by simultaneous drug inhibition of myosin II motors and integrin-mediated adhesions.
Shifting the optimal stiffness for cell migration.
Sex, Cell line
View Samples