This study demonstrates simulated microgravity effects on E. coli K 12 MG1655 when grown on LB medium supplemented with glycerol. The results imply that E. coli readily reprograms itself to combat the multiple stresses imposed due to microgravity. Under these conditions it survives by upregulating oxidative stress protecting genes and simultaneously down regulating the membrane transporters and synthases to maintain cell homeostasis.
Effect of simulated microgravity on E. coli K12 MG1655 growth and gene expression.
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View SamplesDrug-induced kidney injury, largely caused by proximal tubular intoxicants, limits development and clinical use of new and approved drugs. Assessing preclinical nephrotoxicity relies on animal models that are frequently insensitive, and thus, novel techniques, including human microphysiological systems, or “organs on chips,” are proposed to accelerate drug development and predict safety. Polymyxins are potent antibiotics against multidrug-resistant microorganisms; yet clinical use remains restricted because of high risk of nephrotoxicity and limited understanding of toxicological mechanisms. To mitigate risks, structural analogs of polymyxins (NAB739 and NAB741) are currently in clinical development. Using a microphysiological system to model human kidney proximal tubule, we exposed cells to polymyxin B (PMB) and observed significant increases of injury signals, including kidney injury molecule-1 KIM-1and a panel of injury-associated miRNAs (each P < 0.001). Surprisingly, transcriptional profiling identified cholesterol biosynthesis as the primary cellular pathway induced by PMB (P = 1.2 ×10–16), and effluent cholesterol concentrations were significantly increased after exposure (P < 0.01). Additionally, we observed no upregulation of the nuclear factor (erythroid derived-2)–like 2 pathway despite this being a common pathway upregulated in response to proximal tubule toxicants. In contrast with PMB exposure, minimal changes in gene expression, injury biomarkers, and cholesterol concentrations were observed in response to NAB739 and NAB741. Our findings demonstrate the preclinical safety of NAB739 and NAB741 and reveal cholesterol biosynthesis as the novel (to our knowledge) pathway for PMB- induced injury. To our knowledge, this is the first demonstration of a human-on-chip platform used for simultaneous safety testing of new chemical entities and defining unique toxicological pathway responses of an FDA-approved molecule. Overall design: Cells from six donors were seeded into a total of 74 kidney chips, and effluents of kidney MPS were exposed for 48 hours of treatments
Human kidney on a chip assessment of polymyxin antibiotic nephrotoxicity.
Specimen part, Treatment, Subject
View SamplesKCL-22 is a chronic myeloid leukemia (CML) cell line derived from a patient in blast crisis phase and harbors the BCR-ABL translocation. The catalytic (ATP-competitive) BCR-ABL inhibitors imatinib and nilotinib have dramatically improved CML patient outcome, but the development of resistance remains a clinical challenge. The recent identification of allosteric BCR-ABL inhibitors, such as GNF-2, which target the enzyme by binding to the myristoyl pocket rather than catalytic site of ABL1, may provide a strategy to broadly overcome resistance to the class of ABL1 ATP competitive inhibitors. We therefore wanted to use the ClonTracer barcoding system to compare the clonal responses of KCL-22 to imatinib, nilotinib and GNF-2. RNA-seq was employed to characterize genetic alterations and gene expression signatures in the pooled cell populations resistant to BCR-ABL inhibitors as well as single clones showing differential response to the three inhibitors. Overall design: mRNA profiling of the subpopulations and single clones of human CML cell line KCL-22 that contribute to BCR-ABL inhibitor resistance
Studying clonal dynamics in response to cancer therapy using high-complexity barcoding.
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View SamplesThe non-small cell lung cancer (NSCLC) cell line HCC827 harbors an activating EGFR mutation (exon 19 deletion) that confers sensitivity to the FDA-approved EGFR inhibitor erlotinib. By applying the ClonTracer barcoding system, we were able to show the presence of pre-existing sub-populations in HCC827 that contribute to erlotinib resistance. Prior studies implicated that MET amplification confers resistance to erlotinib in this cell line. Therefore we examined the effects of the c-Met inhibitor crizotinib on the barcoded HCC827 population when treated either sequentially or simultaneously with both inhibitors. Despite the significant reduction in barcode complexity, the erlotinib/crizotinib combination treatment failed to eradicate all of the resistant clones implying the presence of an erlotinib/crizotinib dual resistant subpopulation. We performed transcriptome profiling (RNA-seq) to elucidate the potential resistance mechanisms of the dual resistant subpopulation in comparison to vehicle-treated or single agent erlotinib-resistant HCC827 cell populations as controls. Overall design: mRNA profiling of the subpopulations of human NSCLC cell line HCC827 that contribute to EGFR inhibitor erlotinib and MET inhibitor crizotinib resistance
Studying clonal dynamics in response to cancer therapy using high-complexity barcoding.
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View SamplesTo examine irreversible changes in the developing brain following seizures, juvenile inbred mice were intraperitoneally injected with kainate and nicotine.
Increased expression of the lysosomal protease cathepsin S in hippocampal microglia following kainate-induced seizures.
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View SamplesAsthma is a chronic inflammatory respiratory disease affecting over 300 million people around the world. Some asthma patients remain poorly controlled by conventional therapies and experience more life-threatening exacerbations. While patients with severe, refractory disease represent a heterogeneous group, a feature shared by most includes glucocorticoid insensitivity. We sought to characterize differences in the airway smooth muscle transcriptome response to glucocorticoids in fatal asthma vs. non-asthma donors. RNA-Seq was used to measure airway smooth muscle transcript expression differences between 9 donors with fatal asthma and 8 non-asthma donors. Cells from each donor were treated with budesonide or with vehicle control. Poly(A)-selected RNA-Seq libraries were prepared with the Illumina TruSeq method. An Illumina HiSeq 2500 instrument was used to generate 125 base pair paired-end reads. Overall design: Transcriptome profiles obtained via RNA-Seq for airway smooth muscle cells from 9 fatal asthma and 8 non-asthma donors treated with budesonide (100nM for 24h) or vehicle control were compared
Airway Smooth Muscle-Specific Transcriptomic Signatures of Glucocorticoid Exposure.
Specimen part, Disease, Disease stage, Treatment, Subject
View Samples-chloroprene (2-chloro-1,3-butadiene), a monomer used in the production of neoprene elastomers, is of regulatory interest due to the production of multi-organ tumors in mouse and rat cancer bioassays. A significant increase in female mouse lung tumors was observed at the lowest exposure concentration of 12.8 ppm while a small, but not statistically significant, increase was observed in female rats only at the highest exposure concentration of 80 ppm. The metabolism of chloroprene results in the generation of reactive epoxides and the rate of overall chloroprene metabolism is highly species dependent. To identify potential key events in the mode-of-action of chloroprene lung tumorigenesis, dose response and time course gene expression microarray measurements were made in the lungs of female mice and female rats. The gene expression changes were analyzed using both a traditional analysis of variance approach followed by pathway enrichment analysis and a pathway-based benchmark dose (BMD) analysis approach. Pathways related to glutathione biosynthesis and metabolism were the primary pathways consistent with cross-species differences in tumor incidence and transcriptional BMD values for the pathway were more similar to differences in tumor response than were estimated target tissue dose surrogates based on the total amount of chloroprene metabolized per unit mass of lung tissue per day. The closer correspondence of the transcriptional changes with the tumor response are likely due to their reflection of the overall balance between metabolic activation and detoxication reactions whereas the current tissue dose surrogate reflects only oxidative metabolism.
Cross-species transcriptomic analysis of mouse and rat lung exposed to chloroprene.
Sex, Age, Specimen part, Subject
View SamplesOur previous studies have revealed that treatment of pregnant rats with 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD, 1 g/kg) at gestational day (GD) 15 reduces the pituitary synthesis of luteinizing hormone (LH) during late fetal and early postnatal period, leading to imprinting of defects in sexual behaviors at adulthood. However, it remains obscure how the attenuation of pituitary LH links to sexual immaturity. To address this issue, we firstly performed a DNA microarray analysis to identify the gene(s) responsible for dioxin-induced sexual immaturity, using the pituitary and hypothalamus of male pups, at the age of postnatal day (PND)70, born from TCDD-treated dams. Among the reduced genes, we focused on gonadotropin-releasing hormone (GnRH) in the hypothalamus, because of its role in sexual behaviors suggested so far. The present study strongly suggests that maternal exposure to TCDD fixes the status of the lowered expression of GnRH in the offspring by reducing steroidogenesis at perinatal stage, and this is the mechanism for the imprinting of defects in sexual behaviors at adulthood.
Maternal exposure to dioxin imprints sexual immaturity of the pups through fixing the status of the reduced expression of hypothalamic gonadotropin-releasing hormone.
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View SamplesWe hypothesized that gene expression in lungs of Fra-1+/+ and Fra-1-/- mice are divergent thus contributing fibrosis. More specifically, Fra-1-/- mice are increased susceptible to fibrosis. In order to test these hypotheses at the gene expression level, we utilized microarray analysis to examine transcriptional differences between Fra-1+/+ and Fra-1-/- mice at early time point.
Expression profiling of genes regulated by Fra-1/AP-1 transcription factor during bleomycin-induced pulmonary fibrosis.
Sex, Age, Specimen part
View SamplesRATIONALE: Mechanical ventilation (MV) is an indispensable therapy for critically ill patients with acute lung injury and the adult respiratory distress syndrome. However, the mechanisms by which conventional MV induces lung injury remain unclear. OBJECTIVES: We hypothesized that disruption of the gene encoding Nrf2, a transcription factor which regulates the induction of several antioxidant enzymes, enhances susceptibility to ventilator-induced lung injury (VILI), while antioxidant supplementation attenuates such effect. METHODS: To test our hypothesis and to examine the relevance of oxidative stress in VILI, here we have assessed lung injury and inflammatory responses in Nrf2-deficient (Nrf2(-/-)) mice and wildtype (Nrf2(+/+)) animals following acute (2 h) injurious model of MV with or without administration of antioxidant. MEASUREMENTS AND MAIN RESULTS: Nrf2(-/-) mice displayed greater levels of lung alveolar and vascular permeability and inflammatory responses to MV as compared to Nrf2(+/+) mice. Nrf2-deficieny enhances the levels of several pro-inflammatory cytokines implicated in the pathogenesis of VILI. We found diminished levels of critical antioxidant enzymes and redox imbalance by MV in the lungs of Nrf2(-/-) mice; however antioxidant supplementation to Nrf2(-/-) mice remarkably attenuated VILI. When subjected to clinically relevant prolong period of MV, Nrf2(-/-) mice displayed greater levels of VILI than Nrf2(+/+) mice. Expression profiling revealed lack of induction of several VILI genes, stress response and solute carrier proteins and phosphatases in Nrf2(-/-) mice. CONCLUSIONS: Collectively, our data demonstrate for the first time a critical role for Nrf2 in VILI, which confers protection against cellular responses induced by MV by modulating oxidative stress.
Genetic and pharmacologic evidence links oxidative stress to ventilator-induced lung injury in mice.
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