Project description:Hydrogen sulfide (H2S) is a naturally occurring gas that is also associated with several industries. The potential for widespread human inhalation exposure to this toxic gas is recognized as a public health concern. The nasal epithelium is particularly susceptible to H2S-induced pathology. Injury to and regeneration of the nasal respiratory mucosa occurred in animals with ongoing H2S exposure suggesting that the regenerated respiratory epithelium undergoes an adaptive response and becomes resistant to further H2S induced toxicity. To better understand this adaptive response, twenty-four naive 10-week old male Sprague-Dawley rats were exposed to air or 200 ppm H2S in a nose-only exposure system for 3h/d for 1 or 5 consecutive days. Nasal respiratory epithelial cells at the site of injury and regeneration were laser capture microdissected and gene expression profiles were generated at time 3h, 6h, 24h, and 144h post initial exposure using the Affymetrix Rat Genome 430 2.0 microarray. Gene ontology enrichment analysis identified early gene changes in such functional categories as signal transduction, inflammatory/defense response, cell cycle, and response to oxidative stress. Later gene changes occurred in categories involved in cell cycle, DNA repair, transport, and micro-tubule-based movement. These data contribute to our understanding of the nasal epithelial cells? response to inhaled environmental toxicants. A better understanding of the H2S cytotoxicity mechanism will improve human risk assessment. Experiment Overall Design: Twenty-four naive 10-week old male Sprague-Dawley rats were exposed to air or 200 ppm H2S in a nose-only exposure system for 3h/d for 1 or 5 consecutive days. Nasal respiratory epithelial cells at the site of injury and regeneration were laser capture microdissected and gene expression profiles were generated at time 3h, 6h, 24h, and 144h post initial exposure using the Affymetrix Rat Genome 430 2.0 microarray.
Project description:Hydrogen sulfide (H2S) is a naturally occurring gas that is also associated with several industries. The potential for widespread human inhalation exposure to this toxic gas is recognized as a public health concern. The nasal epithelium is particularly susceptible to H2S-induced pathology. Injury to and regeneration of the nasal respiratory mucosa occurred in animals with ongoing H2S exposure suggesting that the regenerated respiratory epithelium undergoes an adaptive response and becomes resistant to further H2S induced toxicity. To better understand this adaptive response, twenty-four naive 10-week old male Sprague-Dawley rats were exposed to air or 200 ppm H2S in a nose-only exposure system for 3h/d for 1 or 5 consecutive days. Nasal respiratory epithelial cells at the site of injury and regeneration were laser capture microdissected and gene expression profiles were generated at time 3h, 6h, 24h, and 144h post initial exposure using the Affymetrix Rat Genome 430 2.0 microarray. Gene ontology enrichment analysis identified early gene changes in such functional categories as signal transduction, inflammatory/defense response, cell cycle, and response to oxidative stress. Later gene changes occurred in categories involved in cell cycle, DNA repair, transport, and micro-tubule-based movement. These data contribute to our understanding of the nasal epithelial cells? response to inhaled environmental toxicants. A better understanding of the H2S cytotoxicity mechanism will improve human risk assessment. Keywords: Time course
Project description:The nasal epithelium is an important target site for chemically-induced toxicity and carcinogenicity. Human epidemiological investigations and experimental laboratory animal studies show that the nasal olfactory epithelium is selectively damaged by inhalation exposure to several chemicals, including vinyl acetate and hydrogen sulfide. The reason for the relative sensitivity of the nasal olfactory epithelium is not known. To better understand and predict the response of the nasal epithelium to inhaled xenobiotics, gene expression profiles from naÑve male and female Sprague-Dawley rats were constructed. Epithelial cells were manually collected from the nasal septum, naso- and maxillo-turbinates, and ethmoid turbinates of 9 male and 9 female rats. Gene expression analysis was performed using the Affymetrix Rat Genome 430 2.0 microarray. Gene ontology enrichment analysis identified several functional categories including xenobiotic metabolism, cell cycle, apoptosis, and ion channel/transport with significantly different expression between tissue types. Surprisingly, there were few gender differences in gene expression. This baseline data will contribute to our understanding of the normal physiology and selectivity of the nasal epithelial cellsâ response to inhaled environmental toxicants. Experiment Overall Design: To better understand and predict the response of the nasal epithelium to inhaled xenobiotics, gene expression profiles from naÑve male and female Sprague-Dawley rats were constructed. Epithelial cells were manually collected from the nasal septum, naso- and maxillo-turbinates, and ethmoid turbinates of 9 male and 9 female rats. Gene expression analysis was performed using the Affymetrix Rat Genome 430 2.0 microarray.
Project description:The nasal epithelium is an important target site for chemically-induced toxicity and carcinogenicity. Human epidemiological investigations and experimental laboratory animal studies show that the nasal olfactory epithelium is selectively damaged by inhalation exposure to several chemicals, including vinyl acetate and hydrogen sulfide. The reason for the relative sensitivity of the nasal olfactory epithelium is not known. To better understand and predict the response of the nasal epithelium to inhaled xenobiotics, gene expression profiles from naїve male and female Sprague-Dawley rats were constructed. Epithelial cells were manually collected from the nasal septum, naso- and maxillo-turbinates, and ethmoid turbinates of 9 male and 9 female rats. Gene expression analysis was performed using the Affymetrix Rat Genome 430 2.0 microarray. Gene ontology enrichment analysis identified several functional categories including xenobiotic metabolism, cell cycle, apoptosis, and ion channel/transport with significantly different expression between tissue types. Surprisingly, there were few gender differences in gene expression. This baseline data will contribute to our understanding of the normal physiology and selectivity of the nasal epithelial cells’ response to inhaled environmental toxicants. Keywords: Comparative
Project description:Formaldehyde, an important industrial chemical, is used for multiple commercial purposes throughout the industrialized world. This simple, one carbon aldehyde is a natural metabolite formed in cells throughput the body. However, it is also a rodent nasal carcinogen, when inhaled by rats every day for two-years at irritant concentrations. High tumor incidences occur at concentration of 10 ppm and above; no tumors are observed at concentrations below 6.0 ppm. The US Environmental Protection Agency (US EPA) is now (2007) conducting a risk assessment to try to evaluate possible cancer risks for much lower levels of human exposure. Sensitive methods are needed to evaluate tissue responses below those concentrations that are clearly irritant or carcinogenic. This microarray study was undertaken to evaluate the mode of action for nasal responses to inhaled formaldehyde in Fisher 344 rats over a range of exposure concentrations. The range of concentrations used spanned those at which virtually no tissue responses were observed (0.7 ppm) to those that represent the highest concentration in the cancer studies (15 ppm) that produced nasal tumors in half the exposed group of rats. The study identified doses at which there were no statistically significant changes in gene expression; intermediate doses with changes in a small number of genes not easily grouped by function; and then concentrations where changes were consistent with irritation and cell stress responses. Experiment Overall Design: Eight week old male F344/NCrl rats were exposed to formaldehyde through either instillation or inhalation. For animals exposed via instillation, 40 ul per nostril of 400 mM formaldehyde was instilled intranasally. Vehicle control animals were instilled with 40 ul per nostril of distilled water. All animals exposed via instillation were sacrificed 6 hours post-exposure. For animals exposed via inhalation, whole-body exposures were performed at doses of 0, 0.7, 2, 6, and 15 ppm (6 hours per day, 5 days per week). Inhalation animals were sacrified at 6 hours, 24 hours, 5 days, and 19 days following initiation of exposure except for the 15 ppm concentration which was sacrificed at only the 6 hour time point. Following sacrifice, tissue from the Level II region of the nose was dissected and digested with a mixture of proteases to remove the epithelial cells. The epithelial cells scquired from this section of the nose consisted primarily of transitional epithelium with some respiratory epithelium. Microarray analysis was performed on the epithelial cells.
Project description:In addition to gaining knowledge on in vivo miRNA responses to formaldehyde, we set out to relate these miRNA responses to transcriptional profiles modified by formaldehyde. Rats were exposed by inhalation to either 0 or 2 ppm formaldehyde (6 hours/day) for 28 days. Genome-wide transcriptional profiles and associated signaling pathways were assessed within the nasal respiratory mucosa and circulating mononuclear white blood cells (WBC). Male Fischer rats received nose-only inhalation exposures of 2 ppm formaldehyde for 7 days or 28 days (6 hours/day). Control (unexposed) rats were placed in nose-only exposure tubes containing room air for the same duration. After the last exposure period, animals were euthanized. RNA were assessed from sampes collected from the nasal epithelium and circulating white blood cells. Genome-wide mRNA expression profiles were evaluated using microarrays.
Project description:The aim of this experiment was to determine how exposure of Hydrogen sulfide impacts gene expression in Mycobacterium tuberculosis. RNA was isolated from actively growing mycobacterial cells (0.6-0.8 OD600) using Trizol according to established protocols (27). Briefly, cells were exposed to 25 µM GYY4137 for 1 hr under carefully controlled conditions (n=3/group) and RNA isolated. Unexposed cells received spent GYY4137 (without any capacity to produce Hydrogen sulfide).
Project description:RNAseq analysis of laser capture microdissected ileal epithelial cells from stopFlox(control) and stopdIEC (epithelium-specific vitamin A signaling knockdown) mice