Lung Tissue Gene Expression Profiles in Mice Exposed to Multi-walled Carbon Nanotubes.
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ABSTRACT: Pulmonary exposure to multi-walled carbon nanotubes (MWCNT) is established to cause local acute and chronic inflammation, fibroproliferative responses, immunotoxicity, and systemic responses in rodent studies. However, the search for representative biomarkers of exposure is an ongoing endeavor. Whole blood gene expression profiling is a promising new approach for the identification of novel disease biomarkers over more invasive methods. We asked if the whole blood transcriptome reflects pathology-specific changes in lung gene expression caused by aspiration of MWCNT. To answer this question, we performed mRNA sequencing analysis of the whole blood and lung tissue in a murine model of MWCNT bolus pharyngeal aspiration.
Project description:Pulmonary exposure to multi-walled carbon nanotubes (MWCNT) is established to cause local acute and chronic inflammation, fibroproliferative responses, immunotoxicity, and systemic responses in rodent studies. However, the search for representative biomarkers of exposure is an ongoing endeavor. Whole blood gene expression profiling is a promising new approach for the identification of novel disease biomarkers over more invasive methods. We asked if the whole blood transcriptome reflects pathology-specific changes in lung gene expression caused by aspiration of MWCNT. To answer this question, we performed mRNA sequencing analysis of the whole blood and lung tissue in a murine model of MWCNT bolus pharyngeal aspiration.
Project description:As the application of carbon nanotubes (CNT) in consumer products continues to rise, studies have expanded to determine the associated risks of exposure on human and environmental health. In particular, several lines of evidence indicate that exposure to multi-walled carbon nanotubes (MWCNT) could pose a carcinogenic risk similar to asbestos fibers. However, to date the potential markers of MWCNT exposure are not yet explored in humans. Global mRNA and lncRNA expression profiles in the whole blood of exposed workers, having direct contact with MWCNT aerosols for atleast 6 months (n=8), were compared with expression profiles of non-exposed (n=7) workers (e.g., proffessional and/or technical staff) from the same manufacturing facility.
Project description:This study compared global multi-walled carbon nanotube (MWCNT)-induced miRNA expression from human lung epithelial and microvascular endothelial cells in monoculture and coculture with miRNA expression from mouse lungs exposed to MWCNT. The concordant miRNA in human cell lines, mouse lung tissues and blood will be potential biomarkers for occupational and medical surveillance.
Project description:The projected increase in the production and use of nanomaterials is expected to result in a corresponding increase in human exposure, potentially resulting in significant morbidity and mortality. Currently, the lung toxicity of multi-walled carbon nanotubes (MWCNT), a prototype nanomaterial, was investigated in a rat model. The rats were exposed by whole-body inhalation to air (controls) or MWCNT (6 hours/day, 3 days) to result in cumulative doses of 180, 90, 45, 22.5, or 11.25 mg/m3. Lung toxicity and gene expression profiles were determined in the lungs of the control and MWCNT exposed rats one day following termination of the exposures. Moderate lung histological changes, indicative of toxicity, were detected in rats exposed to MWCNT at doses > 45 mg/m3. Changes in toxicity parameters including, lactate dehydrogenase (LDH) activity, oxidant production, cell counts of phagocytes, and cytokine levels were detected in the bronchoalveolar lavage of rats exposed to > 22.5 mg/m3 MWCNT, compared with the air controls. Lung gene expression profiling detected differences in transcript levels (fold change >1.5 and FDR p<0.05) of several genes in the rats exposed to >22.5 mg/m3 MWCNT, compared with the controls. The changes in lung toxicity and gene expression profiles exhibited a dose-response to the MWCNT administered in the rats.
Project description:As the application of carbon nanotubes (CNT) in consumer products continues to rise, studies have expanded to determine the associated risks of exposure on human and environmental health. In particular, several lines of evidence indicate that exposure to multi-walled carbon nanotubes (MWCNT) could pose a carcinogenic risk similar to asbestos fibers. However, to date the potential markers of MWCNT exposure are not yet explored in humans.
Project description:Adverse lung effects in rodents following pulmonary exposure to multi-walled carbon nanotubes (MWCNT) are well documented. However, systemic effects are less understood. Prospective epidemiological studies have shown increased cardiovascular disease risk after pulmonary exposure to airborne particles, which has led to concerns that inhalation exposure to MWCNT might pose similar risks. We used high-content genomics tools to compare hepatic responses after exposure to a short, entangled MWCNT to the hepatic responses after exposure to a long, stiffer MWCNT at the global transcriptomic level. Female C57BL/6 mice were exposed by single intratracheal instillation to 162 M-BM-5g/mouse of a short MWCNT (NRCWE-26 (NC-7000), 847M-BM-1102 nm in length) or long MWCNT (NM-401 (CP-0006-SG), 4048M-BM-1366 nm in length). Liver tissues were harvested 24 h, 3 d and 28 d after exposure. This experiment examined the pulmonary transcriptional response of female C57BL/6 mice exposed to NRCWE-26, a short multi-walled carbon nanotube, and NM-401, a long multi-walled carbon nanotube, at three doses: D1 (18 M-NM-<g), D2 (54 M-NM-<g), D3 (162 M-NM-<g), and vehicle control. Each dose group was examined 1, 3 or 28 days post-exposure. Each dose group had 6 biological replicates. There were a total of 72 samples included in the final analysis using a two-color reference design.
Project description:There is a current interest in reducing the in vivo toxicity testing of nanomaterials in animals by increasing toxicity testing using in vitro cellular assays; however, toxicological results are seldom concordant between in vivo and in vitro models. This study compared global multi-walled carbon nanotube (MWCNT)-induced gene expression from human lung epithelial and microvascular endothelial cells in monoculture and coculture with gene expression from mouse lungs exposed to MWCNT. Using a cutoff of 10% false discovery rate and 1.5 fold change, we determined that there were more concordant genes (gene expression both up- or downregulated in vivo and in vitro) expressed in both cell types in coculture than in monoculture. When reduced to only those genes involved in inflammation and fibrosis, known outcomes of in vivo MWCNT exposure, there were more disease-related concordant genes expressed in coculture than monoculture. Additionally, different cellular signaling pathways are activated in response to MWCNT dependent upon culturing conditions. As coculture gene expression better correlated with in vivo gene expression, we suggest that cellular cocultures may offer enhanced in vitro models for nanoparticle risk assessment and the reduction of in vivo toxicological testing.
Project description:Adverse lung effects in rodents following pulmonary exposure to multi-walled carbon nanotubes (MWCNT) are well documented. However, systemic effects are less understood. Prospective epidemiological studies have shown increased cardiovascular disease risk after pulmonary exposure to airborne particles, which has led to concerns that inhalation exposure to MWCNT might pose similar risks. We used high-content genomics tools to compare hepatic responses after exposure to a short, entangled MWCNT to the hepatic responses after exposure to a long, stiffer MWCNT at the global transcriptomic level. Female C57BL/6 mice were exposed by single intratracheal instillation to 162 µg/mouse of a short MWCNT (NRCWE-26 (NC-7000), 847±102 nm in length) or long MWCNT (NM-401 (CP-0006-SG), 4048±366 nm in length). Liver tissues were harvested 24 h, 3 d and 28 d after exposure.
Project description:The immunomodulatory effects seen with exposure to multiwalled carbon nanotubes (MWCNTs) are key events in the progression to pathological outcomes. Therefore, the study of MWCNT induced immunotoxicity is crucial in determining risks posed to human health. MWCNT exposure most commonly occurs via airways, where macrophages are first line responders. Here we exploit an in vitro assay, measuring dose-dependent secretion of a wide panel of cytokines secreted from THP-1 macrophages, as a measure of immunotoxicity following the non-lethal, multi-dose exposure (IC5, IC10 and IC20) to 7 MWCNTs with different intrinsic properties. We find that an underlying tangled structure, and small aspect ratio are key properties predicting MWCNT induced immunotoxicity, mediated predominantly by IL1β cytokine secretion. To assess the mechanism of action giving rise to MWCNT immunotoxicity, a transcriptomics analysis was linked to cytokine secretion in a multilayer model established through correlation across exposure concentrations and time points. This reinforced the finding that tangled MWCNTs have greater immunomodulatory potency, displaying enrichment of immune system, signal transduction and pattern recognition associated pathways. Together our results further elucidate how structure, length and aspect ratio; critical intrinsic properties of MWCNTs, are tied to immunotoxicity.
Project description:Pulmonary exposure to multiwalled carbon nanotubes (MWCNT) induces an inflammatory and rapid fibrotic response, although the long-term signaling mechanisms are unknown. The aim of this study was to examine the effects of 1, 10, 40, or 80 μg MWCNT administered by pharyngeal aspiration on bronchoalveolar lavage (BAL) fluid for polymorphonuclear cell (PMN) infiltration, lactate dehydrogenase (LDH) activity, and lung histopathology for inflammatory and fibrotic responses in mouse lungs 1 mo, 6 mo, and 1 yr postexposure. Further, a 120-μg crocidolite asbestos group was incorporated as a positive control for comparative purposes. Results showed that MWCNT increased BAL fluid LDH activity and PMN infiltration in a dose-dependent manner at all three postexposure times. Asbestos exposure elevated LDH activity at all 3 postexposure times and PMN infiltration at 1 mo and 6 mo postexposure. Pathological changes in the lung, the presence of MWCNT or asbestos, and fibrosis were noted at 40 and 80 μg MWCNT and in asbestos-exposed mice at 1 yr postexposure. To identify non-invasive miRNA biomarkers, miRNA profiling was performed in blood samples collected from MWCNT exposed mice.