Project description:Data reveal that smokers exhibit distinct gene expression profiles relative to non-smokers and moist snuff consumers. Moist snuff consumer gene expression largely resembles that of non-tobacco consumers. Gene expression profiles were used to identify the effects of combustible (smoking) and non-combustible tobacco (moist snuff) products use.
Project description:Alternations in gene methylation and other epigenetic changes regulate normal development as well as drive disease progression. Chronic cigarette smoking causes hyper- and hypo-methylation of genes that could contribute to smoking-related diseases. It is unclear whether consumers of non-combustible tobacco, such as moist snuff, also exhibit such perturbations in their methylome. Here, we present global methylation changes relative to non-tobacco consumers in buccal cells collected from smokers (SMK) and moist snuff consumers (MSC). Generally healthy adult male study subjects were recruited into SMK, MSC and Non-Tobacco Consumer (NTC) cohorts (40 subjects/cohort). Global methylation profiling was performed on the Illumina 450K methylation array using buccal cell DNA. A total of 1,252 loci were found to be significantly differentially methylated in tobacco consumers relative to non-tobacco consumers. Overall, the SMK cohort exhibited larger qualitative and quantitative changes relative to MSC. Approximately half of the total number of gene loci, classified as Combustible Tobacco-Related signatures, and a third of the changes, termed Tobacco-Related signatures, were commonly detected in the tobacco consumers. Very few differences were detected between MSC and NTC, and hierarchical clustering of the top 50 significant gene loci suggested that MSC and NTC co-cluster. Consistent with physiological functions of AhR, combustible tobacco drives profound changes in buccal cell methylation status, principally impacting cell development and immune response pathways. These results aid in placing combustible and non-combustible tobacco products along a risk continuum and provide additional insights into the effects of tobacco consumption.
Project description:Cigarette smoking exerts diverse physiological effects including immune suppression. Existing US epidemiological data show that consumption of smokeless tobacco products, such as moist snuff, is less harmful relative to cigarette smoking. In efforts to understand the molecular changes due to consumption of different tobacco product classes, we have shown recently that smokers exhibit distinct peripheral blood mononuclear cells (PBMCs) gene expression patterns relative to moist snuff users and non-tobacco consumers (NTCs). To better characterize the biological effects exerted from the use of different tobacco products, a genome-wide gene expression study, using a cultured PBMC model, was performed. Global gene expression profiling results showed that 5,421 genes (2,809 upregulated and 2,612 downregulated) were dose-dependently changed by WSCM (pFDR < 0.01). Some gene expression changes detected in the cultured system were also observed in clinical studies. For example, FEZ1 and SLAMF7 were suppressed by WSCM while CCR2 and HHEX genes were upregulated by WSCM commonly in the cultured experiment and clinical studies. WSCM exposures, but not STE, uniquely affected genes involved in immune cell development and inflammatory response. Ingenuity Pathway Analysis identified upstream regulators, such as TNF, IL1β, and NFκB to be likely responsible for the observed gene expression changes and that these cascading signals were generally suppressed by WSCM, but not STE. Collectively, these findings sµggested that combustible and non-combustible tobacco products produce distinct biological effects which could explain the observed chronic immune suppression in smokers.
Project description:Cigarette smoking exerts diverse physiological effects including immune suppression. Existing US epidemiological data show that consumption of smokeless tobacco products, such as moist snuff, is less harmful relative to cigarette smoking. In efforts to understand the molecular changes due to consumption of different tobacco product classes, we have shown recently that smokers exhibit distinct peripheral blood mononuclear cells (PBMCs) gene expression patterns relative to moist snuff users and non-tobacco consumers (NTCs). To better characterize the biological effects exerted from the use of different tobacco products, a genome-wide gene expression study, using a cultured PBMC model, was performed. Gene expression profiles from PBMCs treated with low equi-nicotine units (0.3 µg/ml) of WS-CM and a single high dose of STE (100 µg/ml) were similar to those from untreated controls. Cells treated with medium and high equi-nicotine unit doses of WS-CM (1.0 and 3.0 µg/ml) exhibited significantly different gene expression profiles compared to the low equi-nicotine WS-CM dose and STE. Pre-treatment with higher doses of WS-CM inhibited the expression of several pro-inflammatory genes that regulate immune responses, including IFNγ, TNFα, and IL-2. Gene expression changes of these genes and other cytokine signaling genes were confirmed by qRT-PCR. Moreover, secretion of IFNγ, TNFα and IL-2 proteins was abolished by WS-CM pre-treatment even after 24 hours of toll like receptor stimulation. Additionally, pathway analyses revealed that higher doses of WS-CM inhibited NF-ĸβ signaling and a wide range of signaling pathways associated with immune cell differentiation and inflammatory responses, and increased expression of genes involved in apoptosis. Collectively, our results show that pre-treatment of PBMCs with higher doses of WS-CM inhibits immune activation and effector cytokine expression and secretion, resulting in a reduced immune response, whereas STE had minimal effect.
2019-09-25 | GSE127977 | GEO
Project description:U.S. Domestic Moist Snuff Microbial And Chemistry Survey
Project description:A tissue like buccal mucosa (from cheek swabs) would be an ideal sample material for rapid, easy collection for testing of biomarkers as an alternative to blood. A limited number of studies, primarily in the smoker/oral cancer literature, address this tissue's efficacy for quantitative PCR or microarray gene expression analysis. In this study both qPCR and microarray analyses were used to evaluate gene expression in buccal cells. An initial study comparing blood and buccal cells from the same individuals looked at relative amounts of four genes. The RNA isolated from buccal cells was degraded but was of sufficient quality to be used with RT-qPCR to detect expression of specific genes. Second, buccal cell RNA was used for microarray-based differential gene expression studies by comparing gene expression between smokers and nonsmokers. The isolation and amplification protocol allowed use of 150-fold less buccal cell RNA than had been reported previously with human microarrays. We report here the finding of a small number of significant gene expression differences between smokers and nonsmokers, using buccal cells as target material. Additionally, Gene Set Enrichment Analysis confirmed that these genes were changing expression in the same pattern as seen in an earlier buccal cell study performed by another group. Our results suggest that in spite of a high degree of RNA degradation, buccal cells from cheek mucosa could be used to detect differential gene expression between smokers and nonsmokers. However the RNA degradation, increase in sample variability and microarray failure rate show that buccal samples should be used with caution as source material in expression studies.
Project description:Genome wide DNA methylation profiling of smokers and non-smokers in PBMC samples. The Illumina Infinium 450k Human DNA methylation Beadchip v1.1 was used to obtain DNA methylation profiles across 485,577 CpGs in PBMC samples. Samples included 24 smokers and 28 non-smokers.
Project description:Genome wide DNA methylation profiling of smokers and non-smokers in PBMC samples. The Illumina Infinium 450k Human DNA methylation Beadchip v1.1 was used to obtain DNA methylation profiles across 485,577 CpGs in PBMC samples. Samples included 50 smokers and 61 non-smokers.
Project description:A tissue like buccal mucosa (from cheek swabs) would be an ideal sample material for rapid, easy collection for testing of biomarkers as an alternative to blood. A limited number of studies, primarily in the smoker/oral cancer literature, address this tissue's efficacy for quantitative PCR or microarray gene expression analysis. In this study both qPCR and microarray analyses were used to evaluate gene expression in buccal cells. An initial study comparing blood and buccal cells from the same individuals looked at relative amounts of four genes. The RNA isolated from buccal cells was degraded but was of sufficient quality to be used with RT-qPCR to detect expression of specific genes. Second, buccal cell RNA was used for microarray-based differential gene expression studies by comparing gene expression between smokers and nonsmokers. The isolation and amplification protocol allowed use of 150-fold less buccal cell RNA than had been reported previously with human microarrays. We report here the finding of a small number of significant gene expression differences between smokers and nonsmokers, using buccal cells as target material. Additionally, Gene Set Enrichment Analysis confirmed that these genes were changing expression in the same pattern as seen in an earlier buccal cell study performed by another group. Our results suggest that in spite of a high degree of RNA degradation, buccal cells from cheek mucosa could be used to detect differential gene expression between smokers and nonsmokers. However the RNA degradation, increase in sample variability and microarray failure rate show that buccal samples should be used with caution as source material in expression studies. Samples were collected from eight subjects, four smokers (Sm)and four nonsmokers (NS). Each cheek was sampled creating an a and b sample for each subject which is reflected in the array name. All samples were isolated separately for total RNA. Each was hybridzed to microarrays to examine for differential gene expression between smokers and nonsmokers. There are 14 total samples in the main dataset (Set 2). One cheek sample failed in microarray analysis for two individuals, 08BCNS23 a and 08BCSm27 a, and so are not included here. A sample set (Set 1) was created which contains the four samples shown in this file. They represent repeated sampling of both cheeks for two individuals to test for reproducibility. There is a separate RMA file and metadata file (this file) for these data. These included samples 08BC11Sm a and b, a smoker, and 08BC12NSa and b a nonsmoker.