Type 1 interferon and pattern recognition receptor signaling following particulate matter inhalation
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ABSTRACT: This study utilized microarray technology as an exploratory search for mechanisms of systemic effects after welding fume inhalation. In addition, the applicability of this methodological approach for determining specific exposure-induced responses was examined. C57Bl/6J mice were exposed to gas metal arc-stainless steel (GMA-SS) welding fume by inhalation for 10 days (3 hours/day) at 40 mg/m3. Microarray analysis was done on lung, blood and aorta from n=4 mice exposed to welding fume or air (control).
Project description:This study utilized microarray technology as an exploratory search for mechanisms of systemic effects after welding fume inhalation. In addition, the applicability of this methodological approach for determining specific exposure-induced responses was examined.
Project description:Exposure to welding fume consists of a mixed exposure of metal-rich particulate matter with gases (ozone, carbon monoxide) and/or vapors (VOCs). Data suggests that welders are immune compromised. Given the inability of pulmonary leukocytes to properly respond to a secondary infection, the question arose concerning how far upstream the dysfunction persisted. Our aim was to evaluate circulating leukocyte functionality after welding fume exposure. The results showed that welding fume exposure has rapid effects on the circulating leukocyte population as identified by relative mRNA expression changes. Instillation of MMA-SS reduced inflammatory protein production of circulating leukocytes when challenged with the secondary stimulus LPS. The effects were not related to transcription, but were observed in conjunction with oxidative stress. Rats were intratracheally instilled (ITI) with phosphate buffered saline or 2 mg of welding fume collected from a manual metal arc-stainles steel weld. Rats were sacrificed 4 and 24 h post-exposure and whole blood was collected. Whole blood was used for cellular differential counts, RNA isolation with subsequent microarray and Ingenuity Pathway Analysis, and secondary stimulation with lipopolysaccharide utilizing TruCulture technology from Myriad/Rules Based Medicine. Also, mononuclear cells were isolated 24 h post-exposure to measure oxidative stress by flow cytometry and confocal microscopy. Whole blood collected 4 and 24 h post-exposure was challenged (a paired non-stimulant (null) and stimulant (LPS) tube) for 24 h using Truculture technology from Myriad/ RBM. After the challenge, cells were recovered using RNA later for subsequent RNA isolation and microarray.
Project description:We examined the impact of chronic lung inflammation on the pulmonary transcriptional response to inhaled urban particles. Transcript levels were measured using high density microarrays in total RNA isolated from whole lungs of wildtype and TNF-α overexpressing mice exposed by inhalation to particulate matter and euthanized immediately or 24 h post-exposure. Keywords: Toxicology, disease state analysis, stress response
Project description:We examined the impact of chronic lung inflammation on the pulmonary transcriptional response to inhaled urban particles. Transcript levels were measured using high density microarrays in total RNA isolated from whole lungs of wildtype and TNF-α overexpressing mice exposed by inhalation to particulate matter and euthanized immediately or 24 h post-exposure. Experiment Overall Design: Transgenic SP-C/TNF-α mice and their wildtype littermates were exposed by inhalation to particulate matter (0, 42 mg/m3 EHC-93) for 4 h and euthanized immediately or 24 h post-exposure (n=5 per treatment per time point, 40 animals total). Agilent 22K oligonucleotide microarrays were used to examine transcript levels in whole lung RNA. Stratagene Universal Mouse RNA was used as a reference.
Project description:Open tenotomy of the Achilles tendon of 6 rats was performed. The animals were divided into two groups according to exposure of PM2.5 (particulate matter less than 2.5 µm): control group (Non-PM group) or PM exposure group (PM group). After 6 weeks of PM exposure, the tendon RNA was extracted and anlyzed.
Project description:Open tenotomy of the Achilles tendon of 6 rats was performed. The animals were divided into two groups according to exposure of PM2.5 (particulate matter less than 2.5 µm): control group (Non-PM group) or PM exposure group (PM group). After 6 weeks of PM exposure, the tendon DNA was extracted and anlyzed. Genome-wide DNA methylation profiles were determinen. DNA amplicons were prepared using Differential Methylation Hybridization (DMH) method, subsequently hybridized on to the Customized Agilent Rat CpG island Microarray. The goal was to unravel the DNA methylation patterns in different subgropus of tendon tissue according to partciulate matter exposure.
Project description:Occupational exposure to crystalline silica results in serious health effects, most notably, silicosis and cancer. A proper understanding of the mechanism(s) underlying the initiation and progression of silica-induced pulmonary toxicity is critical for the intervention and/or prevention of the adverse health effects associated with crystalline silica exposure. Rats were exposed to crystalline silica by inhalation at a concentration of 15 mg/m3, 6 hours/day, 5 days/week for 3, 6 or 12 weeks. At the end of each exposure time point, toxicity and global gene expression changes were determined in the lungs. In general, silica exposure resulted in pulmonary toxicity that was dependent on the duration of silica exposure. A significant and silica exposure time-dependent increase in lactate dehydrogenase activity and accumulation of alveolar macrophages and infiltrating neutrophils in the bronchoalveolar lavage fluid suggested crystalline silica-induced pulmonary toxicity in the rats. Histological changes indicative of pulmonary toxicity were detectable only in the lungs of rats that were exposed to silica for 6- or 12-weeks. Minimal, sub-acute pulmonary inflammation consisting mainly of macrophage accumulation and infiltration of neutrophils was seen in 2 out of 8 rats in the 6-week silica exposure group. Chronic active inflammation, type II pneumocyte hyperplasia, and fibrosis were detected following 12-weeks of silica exposure in all rat lungs. In addition, crystalline silica was visible in the lungs of the rats belonging to the 12-week exposure group. A significant increase in the number of neutrophils seen in the blood indicated silica-induced systemic inflammation in the rats. Microarray analysis of the global gene expression profiles of the rat lungs detected significant differential expression (FDR p <0.05 and fold change >1.5) of 38, 77 and 99 genes in the rats exposed to silica for 3-, 6- and 12-weeks, respectively, compared to the time-matched controls. Bioinformatics analysis of the differentially expressed genes identified significant enrichment of functions, networks and pathways related to inflammation, cancer, oxidative stress, fibrosis and tissue remodeling in the lungs of the silica exposed rats. Collectively, the results of our study provided insights into the molecular mechanisms underlying pulmonary toxicity following sub-chronic exposure to silica in rats. 36 samples were analyzed in this experiment. 6 rats were exposed to crystalline silica by inhalation 15 mg/m3, 6 hours/day, 5 days, 3 weeks. 6 rats were exposed to crystalline silica by inhalation 15 mg/m3, 6 hours/day, 5 days, 6 weeks. 6 rats were exposed to crystalline silica by inhalation 15 mg/m3, 6 hours/day, 5 days, 12 weeks. 18 rats served as controls (6 for each 3 week, 6 week, and 12 week exposure) and were exposed to air during treatment times. Lung gene expression profiling was performed using RNA isolated from rat lung samples.