Project description:The capability to detect target organ toxicity as well as to determine the molecular mechanisms underlying such toxicity by employing surrogate biospecimens that can be obtained by a non-invasive or minimally invasive procedure has significant advantage in occupational toxicology. Pulmonary toxicity and global gene expression profile in the lungs, peripheral blood and bronchoalveolar lavage (BAL) cells were determined in rats at 44-weeks following pulmonary exposure to crystalline silica (15 mg/m3, 6-hours/day, 5 days). A significant elevation in lactate dehydrogenase activity and albumin content observed in the BAL fluid suggested the induction of pulmonary toxicity in the silica exposed rats. Similarly, the observation of histological alterations, mainly type II pneumocyte hyperplasia and fibrosis, in the lungs further confirmed silica-induced pulmonary toxicity in the rats. A significant increase in the number of neutrophils and elevated monocyte chemotactic protein 1 level in the BAL fluids suggested silica-induced pulmonary inflammation in the rats. Determination of global gene expression profile in the lungs, BAL cells, and peripheral blood of the silica exposed rats identified 144, 236, and 51 significantly differentially expressed genes (SDEGs), respectively, compared with the corresponding control samples. Bioinformatics analysis of the SDEGs demonstrated a remarkable similarity in the biological functions, molecular networks and canonical pathways that were significantly affected by silica exposure in the lungs, BAL cells and blood of the rats. Induction of inflammation was identified, based on the bioinformatics analysis of the significantly differentially expressed genes in the lungs, blood and BAL cells, as the major molecular mechanism underlying the silica-induced pulmonary toxicity. The findings of our study demonstrated the potential application of global gene expression profiling of peripheral blood and BAL cells as a valuable minimally invasive approach to study silica-induced pulmonary toxicity in rats.

Project description:Murine Pulmonary Responses to Ambient Baltimore Particulate Matter: Genomic Analysis and Contribution to Airway Hyperresponsiveness; Asthma is a complex disease characterized by airway hyperresponsiveness (AHR) and chronic airway inflammation. Environmental factors such as ambient particulate matter (PM), a major air pollutant, has been demonstrated in epidemiological studies to contribute to asthma exacerbation and increased asthma prevalence. OBJECTIVE: We investigated the genomic and pathophysiological effects of Baltimore PM (median diameter 1.78 Âµm) in a murine model of asthma to identify potential biomarkers. METHODS: A/J mice with ovalbumin (OVA) âinduced AHR were exposed to PM (20 mg/kg, intratracheal), and both AHR and bronchoalveolar lavage (BAL) were assayed on days 1, 4, and 7 post exposure. Lung gene expression profiling (Affymetrix Mouse430_ 2.0) by PM (20 mg/kg, intratracheal) were assayed on OVA- and / or PM--challenged mice. RESULTS: Significant increases of airway responsiveness in OVA-treated mice were observed, indicating an asthmatic phenotype. Ambient PM exposure induced significant changes in AHR in both naive mice and OVA-induced asthmatic mice. In both naive and OVA challenged asthmatic mice, PM induced eosinophil and neutrophil infiltration into airways, elevated BAL protein content, and stimulated secretion of TH1 cytokines (IFN-g, IL-6, and TNF-a) and TH2 cytokines (IL-4, IL-5, and eotaxin) into BAL. Consistent with these results, PM induced expression of genes of innate immune response, chemotaxis and complementary system. CONCLUSION: These studies, consistent with epidemiological data, indicate that PM increases AHR and lung inflammation in naÃ¯ve mice and exacerbates the asthma phenotype of increased AHR and gene expression pattern changes correlated with acute lung inflammation and airway damage. We used microarrays to detail the global programme of gene expression induced by rhPBEF treatment and VALI. Experiment Overall Design: animals were treated by PBS, Oval albumin, PM, or both OVA/PM

Project description:Acute lung inflammation can alter the pulmonary function of susceptible individuals and exacerbate the pathogenesis of chronic inflammatory lung diseases including chronic obstructive pulmonary disease (COPD), cystic fibrosis and asthma. Exposure to lipopolysaccharide (LPS) or endotoxin, a constituent of outer cell membrane of gram negative bacteria, induces airway inflammation that is primarily characterized by increased polymorphonuclear neutrophils (PMNs) at early time points. Because LPS is present in variety of occupational and home environments and is an active constituent of cigarette smoke it is a risk factor for increasing prevalence and severity of non-occupational COPD, for adult onset of asthma and for wheezing in children. In airway epithelial cells, LPS stimulation increases mucin gene expression and mucous production. Hypersecretion of mucus overwhelms the ciliary clearance and obstructs airways, causing morbidity and mortality in chronic inflammatory respiratory lung diseases. In addition, acute bacterial infection contributes to the exacerbation of chronic airway diseases, specifically in advanced COPD and CF subjects, leading to increased healthcare burden and higher mortality. Bcl-2, a prosurvival protein that inhibits cell death plays a key role in normal cellular homeostasis and regulates the integrity of the mitochondrial and endoplasmic reticulum membranes. Gain- and loss-of-function studies showed that Bcl-2 expression sustains hyperplastic epithelial cells, and Bcl-2 expression is elevated in airway epithelial cells of subjects with cystic fibrosis and asthma. The present study investigated which inflammatory mediators induce mucous cell metaplasia and Bcl-2 expression following LPS exposure. Microarray analyses of mRNA from airway epithelial cells captured by laser microdissection from rat lungs snap-frozen at day 0 and 2 post LPS exposure were analyzed. Microarray analysis of mRNA from airway epithelial cells captured by laser microdissection from rat lungs snap-frozen at day 0 and day 2 post LPS exposure was performed to identify inflammatory mediators modulated by LPS exposure.

Project description:Pulmonary exposure to high doses of nanoparticles (NP) leads to well characterized lung toxicity in addition to long-term NP retention. However, pulmonary NP accumulation and toxicity following low dose exposures are not well described. In the present study we sought to: (1) investigate particle retention in mouse lungs following intratracheal instillation of varying doses of nano-sized titanium dioxide (nano-TiO2) and (2) determine the effects of long-term particle accumulation on pulmonary systems. Female C57BL/6 mice were exposed to rutile nano-TiO2 (primary size of 20.6 nm and surface area of 107.7 m2/g) via single intratracheal instillations of 18, 54 and 162 M-BM-5g/mouse and sampled 1, 3 and 28 days post-exposure. The deposition of nano-TiO2 in the lungs was assessed using Nanoscale Hyperspectral Microscope. DNA microarrays, pathway-specific real-time RT-PCR (qPCR) and gene-specific qPCR arrays, and tissue protein analyses were employed to characterize pulmonary responses. Hyperspectral mapping showed dose-dependent retention of nano-TiO2 in the lungs up to 28 days post-exposure time. Retention did not correlate with the extent of inflammatory neutrophil influx into the lungs. DNA microarray analysis showed altered expression of approximately 3000 genes across all treatment groups (M-BM-11.3 fold; p<0.1). Several inflammatory mediators changed in a dose- and time-dependent manner at both the mRNA and protein levels. Although the low dose exposure failed to induce observable inflammation, significant changes in the expression of genes and proteins associated with inflammation were observed. Moreover, diminished (or absent) neutrophil influx in the low and medium dose groups was correlated with negative regulation of genes associated with ion homeostasis and muscle regulation. Gene expression changes for several inflammatory mediators have previously been noted in mice exposed to the same nano-TiO2 via inhalation. Our results suggest that retention of nano-TiO2 in the absence of inflammation and effective clearance can perturb calcium and ion homeostasis, and affect smooth muscle activities over time. This experiment consists of three different dosages of TiO2, e.g., low (18 ug), medium (54 ug) and high (162 ug), and one control. There are 3 time points for each treatment and control group, e.g., day 1, day 3 and day 28. Each dose or time point has 5-6 biological replicates. There are total 65 samples (arrays)

Project description:Acute lung inflammation can alter the pulmonary function of susceptible individuals and exacerbate the pathogenesis of chronic inflammatory lung diseases including chronic obstructive pulmonary disease (COPD), cystic fibrosis and asthma. Exposure to lipopolysaccharide (LPS) or endotoxin, a constituent of outer cell membrane of gram negative bacteria, induces airway inflammation that is primarily characterized by increased polymorphonuclear neutrophils (PMNs) at early time points. Because LPS is present in variety of occupational and home environments and is an active constituent of cigarette smoke it is a risk factor for increasing prevalence and severity of non-occupational COPD, for adult onset of asthma and for wheezing in children. In airway epithelial cells, LPS stimulation increases mucin gene expression and mucous production. Hypersecretion of mucus overwhelms the ciliary clearance and obstructs airways, causing morbidity and mortality in chronic inflammatory respiratory lung diseases. In addition, acute bacterial infection contributes to the exacerbation of chronic airway diseases, specifically in advanced COPD and CF subjects, leading to increased healthcare burden and higher mortality. Bcl-2, a prosurvival protein that inhibits cell death plays a key role in normal cellular homeostasis and regulates the integrity of the mitochondrial and endoplasmic reticulum membranes. Gain- and loss-of-function studies showed that Bcl-2 expression sustains hyperplastic epithelial cells, and Bcl-2 expression is elevated in airway epithelial cells of subjects with cystic fibrosis and asthma. The present study investigated which inflammatory mediators induce mucous cell metaplasia and Bcl-2 expression following LPS exposure. Microarray analyses of mRNA from airway epithelial cells captured by laser microdissection from rat lungs snap-frozen at day 0 and 2 post LPS exposure were analyzed. Microarray analysis of mRNA from airway epithelial cells captured by laser microdissection from rat lungs snap-frozen at day 0 and day 2 post LPS exposure was performed to identify inflammatory mediators modulated by LPS exposure. Specific pathogen-free F344/NCrR male rats of 8–10 wk of age (from NCI, Frederick, MD) were exposed to LPS (1000 ug in 0.5 ML Saline) and rats were sacrificed on day 0 and day 2 of LPS exposure. Right lungs were snap-frozen in OCT and airway epithelial cells were captured by laser-dissection microsopy to extract RNA. Gene expression data from nonexposed rats (0d) was used a control.

Project description:Murine Pulmonary Responses to Ambient Baltimore Particulate Matter: Genomic Analysis and Contribution to Airway Hyperresponsiveness Asthma is a complex disease characterized by airway hyperresponsiveness (AHR) and chronic airway inflammation. Environmental factors such as ambient particulate matter (PM), a major air pollutant, has been demonstrated in epidemiological studies to contribute to asthma exacerbation and increased asthma prevalence. OBJECTIVE: We investigated the genomic and pathophysiological effects of Baltimore PM (median diameter 1.78 µm) in a murine model of asthma to identify potential biomarkers. METHODS: A/J mice with ovalbumin (OVA) –induced AHR were exposed to PM (20 mg/kg, intratracheal), and both AHR and bronchoalveolar lavage (BAL) were assayed on days 1, 4, and 7 post exposure. Lung gene expression profiling (Affymetrix Mouse430_ 2.0) by PM (20 mg/kg, intratracheal) were assayed on OVA- and / or PM--challenged mice. RESULTS: Significant increases of airway responsiveness in OVA-treated mice were observed, indicating an asthmatic phenotype. Ambient PM exposure induced significant changes in AHR in both naive mice and OVA-induced asthmatic mice. In both naive and OVA challenged asthmatic mice, PM induced eosinophil and neutrophil infiltration into airways, elevated BAL protein content, and stimulated secretion of TH1 cytokines (IFN-g, IL-6, and TNF-a) and TH2 cytokines (IL-4, IL-5, and eotaxin) into BAL. Consistent with these results, PM induced expression of genes of innate immune response, chemotaxis and complementary system. CONCLUSION: These studies, consistent with epidemiological data, indicate that PM increases AHR and lung inflammation in naïve mice and exacerbates the asthma phenotype of increased AHR and gene expression pattern changes correlated with acute lung inflammation and airway damage. We used microarrays to detail the global programme of gene expression induced by rhPBEF treatment and VALI. Keywords: gene expression

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Carbon black nanoparticles induce biphasic inflammatory responses in the lungs of C56BL/6 mice following single intratracheal instillation

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