Zinc is a common metal in most ambient particulate matter (PM), and has been proposed to be a causative component in PM-induced adverse cardiovascular health effects. Zinc is also an essential metal and has the potential to induce many physiological and nonphysiological changes. Most toxicological studies employ high levels of zinc. We hypothesized that subchronic inhalation of environmentally relevant levels of zinc would cause cardiac changes in healthy rats. To address this question, healthy male WKY rats (12 wks age) were exposed via nose only inhalation to filtered air or 10, 30 or 100 ug/m3 of aerosolized Zn in sulfate form, 5 h/d, 3 d/wk for 16 wks. Necropsies occurred 48 h after the last exposure to ensure effects were due to chronic exposure rather than the last exposure. No significant changes were observed in neutrophil or macrophage count, total lavageable cells, or enzyme activity levels (lactate dehydrogenase, n-acetyl ?-D-glucosaminidase, ?-glutamyl transferase) in bronchoalveolar lavage fluid, indicating minimal pulmonary effect. In the heart, cytosolic glutathione peroxidase activity decreased, while mitochondrial ferritin levels increased and succinate dehydrogenase activity decreased, suggesting a mitochondria-specific effect. Although no cardiac pathology was seen, cardiac gene array analysis indicated changes in genes involved in cell signaling, a pattern concordant with known zinc effects. These data indicate that inhalation of zinc at environmentally relevant levels may induce cardiac effects. While changes are small in healthy rats, these may be especially relevant in individuals with pre-existent cardiovascular disease.
Subchronic inhalation of zinc sulfate induces cardiac changes in healthy rats.
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View SamplesDEP exposure is linked to increases in cardiovascular effects. This effect is enhanced in individuals with pre-existing disease. Animal models of cardiovascular disease are used to study this susceptibility. The heart is rich in mitochondria, which produce high levels of free radicals, leading to inactivation of tricarboxylic acid cycle enzymes. We hypothesized that a 4-wk DEP inhalation would result in strain-related structural impairment of cardiac mitochondria and changes in these enzyme activities in WKY and SHR. Male rats (12-14 wks age) were exposed whole body to air or 0.5 or 2.0 mg/m3 DEP for 6h/d, 5 d/wk for 4 wks. Neutrophilic influx was noted in the bronchoalveolar lavage fluid in both strains. A slightly lower level of baseline cardiac mitochondrial aconitase activity was seen in SHR than WKY. Aconitase activity appeared to be decreased in an exposure related manner in both strains. Significantly higher baseline levels of cardiac cytosolic ferritin and aconitase activity were seen in the SHR than WKY. No exposure-related changes were noted in either of these measures. Mitochondrial succinate and isocitrate dehydrogenase activities were not changed following DEP exposure in either strain. Transmission electron microscopy images of the heart indicated abnormalities in cardiac mitochondria of control SHR but not control WKY. No exposure related ultrastructural changes were induced by DEP in either strain. In conclusion, strain differences in cardiac biomarkers of oxidative stress and structure of mitochondria exist between SHR and WKY. DEP exposure results in small changes in cardiac mitochondrial and cytosolic markers of oxidative stress. (Abstract does not represent USEPA policy.)
One-month diesel exhaust inhalation produces hypertensive gene expression pattern in healthy rats.
Specimen part
View SamplesZinc (Zn) is a major elemental component of respirable ambient particulate matter (PM) detected often at alarming levels in urban air. Exposure to PM has been widely associated with increased cardiovascular morbidity and mortality, however, it is not known what components or sources of PM are causative. We recently demonstrated that long-term episodic inhalation of combustion PM, having similar amount of Zn found in urban PM, caused myocardial lesions in rats. We further demonstrated that a single pulmonary exposure to Zn at high concentration is associated with disturbances in cardiac mitochondrial function, ion channel regulation, calcium homeostasis, and cell signaling. Therefore, in this study we investigated the role of PM-associated Zn in cardiac injury using multiple exposure scenarios. Male Wistar-Kyoto (WKY) rats of 12-14 wks age were intratracheally exposed (once per wk x 8 or16 wks) to either (1) saline (control); (2) PM having no soluble Zn; (3) combustion PM suspension containing 14.5 ug/mg water-soluble Zn at high and (4) low dose levels, (5) the aqueous fraction of this suspension devoid of solid insoluble particulate fraction (14.5 ug/mg soluble Zn), or (6) Zn sulfate. Zn concentrations were identical in groups 3, 5 and 6. Pulmonary toxicity was apparent in all exposure groups when compared to saline as determined by recovery of cells in bronchoalveolar lavage fluid. Long-term exposure to PM with or without soluble Zn, or Zn sulfate caused distinct myocardial lesions characterized by subepicardial and randomly distributed myocardial inflammation, degeneration, and fibrosis. The lesion severity was higher in those groups receiving Zn PM. Because cardiac mitochondria are likely the primary target of inhaled metal or other absorbed PM components, we analyzed mitochondrial DNA damage using QPCR and found that all exposure groups except those exposed to PM without Zn caused variable degree of damage. Aconitase activity, sensitive to inhibition by oxidative stress was inhibited slightly but significantly in rats receiving zinc sulfate. Although modest, microarray (Affymetrix) analysis revealed expression changes in the heart reflective of effects on cell signaling, inflammation/oxidative stress, mitochondrial fatty acid metabolisms and cell cycle regulation in rats exposed to zinc sulfate. However, these changes were minimal following exposure to PM devoid of soluble metals. We demonstrate that episodic subchronic pulmonary exposure to zinc sulfate causes cardiac injury and mitochondrial DNA damage. Thus, water-soluble PM-associated zinc may be one of the PM components responsible for cardiovascular morbidity.
The role of particulate matter-associated zinc in cardiac injury in rats.
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View SamplesAnalysis of umbilical vein endothelial cells (HUVEC) treated with Egr-3 siRNA under the VEGF treatment for 0,1, and 4 h. Egr-3, a member of early growth response family, is immediately and dramatically induced by VEGF in HUVEC, which regulates expression of many genes related to endothelial activation.
Vascular endothelial growth factor activation of endothelial cells is mediated by early growth response-3.
No sample metadata fields
View SamplesAlthough HSF1 is known to play an important role in regulating the cellular response to proteotoxic stressors, little is known about the structure and function of the HSF1 signaling network under both stressed and unstressed conditions. In this study, we used a combination of chromatin immunoprecipitation (ChIP) microarray analysis and time course gene expression microarray analysis with and without siRNA-mediated inhibition of HSF1 comprehensively identify genes directly and indirectly regulated by HSF1 and examine the structure of the extended HSF1 signaling network. Correlation between promoter binding and gene expression was not significant for all genes bound by HSF1 suggesting that HSF1 binding per se is not sufficient for expression. However, the correlation with promoter binding was significant for genes identified as HSF1-regulated following siRNA knockdown allowing the identification of direct transcriptional targets of HSF1. Among promoters bound by HSF1 following heat shock, a gene ontology (GO) analysis showed significant enrichment only in categories related to protein folding. In contrast, analysis of the extended HSF1 signaling network showed enrichment in a variety of categories related to protein folding, anti-apoptosis, RNA splicing, ubiquitination and others, highlighting a complex transcriptional program directly and indirectly regulated by HSF1.
Genome-wide analysis of human HSF1 signaling reveals a transcriptional program linked to cellular adaptation and survival.
No sample metadata fields
View SamplesFezf2 is highly and specifically expressed in mTECs in mouse thymus and Fezf2 deficiency (Fezf2 KO) in the thymus leads to autoimmunity. However, it is unclear how Fezf2 contributes to thymic gene expression.
Fezf2 Orchestrates a Thymic Program of Self-Antigen Expression for Immune Tolerance.
Age, Specimen part
View SamplesGenes regulated by miR-206 were identified by microarray analysis in RD cells transfected with a Negative Control (NC) or miR-206 Mimic
PAX7 is a required target for microRNA-206-induced differentiation of fusion-negative rhabdomyosarcoma.
Specimen part, Cell line, Time
View SamplesTo investigate how the phenotype of macrophages that have engulfed engineered nanoparticles (ENPs) differs from normal macrophages, we conducted Affymetrix microarray studies to identify the gene regulatory pathways affected by the ENPs. To mimic potential occupational exposure scenarios, the experimental design involved pretreatment of mouse primary bone marrow macrophages with the ENPs (25 mg/ml) for 24 hr, followed by removal of residual ENPs and challenging the macrophages with the TLR4 ligand and surrogate bacterial stimulus, lipopolysachharide (LPS) for 4 hr. The 4 hr challenge time was chosen based on preliminary studies which showed many of the proinflammatory gene expression responses peak between 2-6 hr after LPS treatment.
Dysregulation of macrophage activation profiles by engineered nanoparticles.
Specimen part, Treatment
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Genome-wide approaches reveal functional vascular endothelial growth factor (VEGF)-inducible nuclear factor of activated T cells (NFAT) c1 binding to angiogenesis-related genes in the endothelium.
Specimen part, Treatment
View SamplesExperiment design
Glucose-dependent cell size is regulated by a G protein-coupled receptor system in yeast Saccharomyces cerevisiae.
No sample metadata fields
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